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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>
64 <li><a href="#aggregateconstants">Aggregate Constants</a></li>
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>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]68 </ol>
69 </li>
70 <li><a href="#othervalues">Other Values</a>
71 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]72 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]73 </ol>
74 </li>
75 <li><a href="#instref">Instruction Reference</a>
76 <ol>
77 <li><a href="#terminators">Terminator Instructions</a>
78 <ol>
79 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
80 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
81 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
82 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
83 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
84 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
85 </ol>
86 </li>
87 <li><a href="#binaryops">Binary Operations</a>
88 <ol>
89 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
90 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
91 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
92 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
93 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
94 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
95 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
96 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
97 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
98 </ol>
99 </li>
100 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
101 <ol>
102 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
103 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
104 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
105 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
106 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
107 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
108 </ol>
109 </li>
110 <li><a href="#vectorops">Vector Operations</a>
111 <ol>
112 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
113 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
114 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
115 </ol>
116 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]117 <li><a href="#aggregateops">Aggregate Operations</a>
118 <ol>
119 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
120 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
121 </ol>
122 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]123 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
124 <ol>
125 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
126 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
127 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
128 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
129 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
130 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
131 </ol>
132 </li>
133 <li><a href="#convertops">Conversion Operations</a>
134 <ol>
135 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
136 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
137 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
138 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
139 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
140 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
141 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
142 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
143 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
144 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
145 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
146 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
147 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]148 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]149 <li><a href="#otherops">Other Operations</a>
150 <ol>
151 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
152 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]153 <li><a href="#i_vicmp">'<tt>vicmp</tt>' Instruction</a></li>
154 <li><a href="#i_vfcmp">'<tt>vfcmp</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]155 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
156 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
157 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
158 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
159 </ol>
160 </li>
161 </ol>
162 </li>
163 <li><a href="#intrinsics">Intrinsic Functions</a>
164 <ol>
165 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
166 <ol>
167 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
168 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
169 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
170 </ol>
171 </li>
172 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
173 <ol>
174 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
175 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
176 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
177 </ol>
178 </li>
179 <li><a href="#int_codegen">Code Generator Intrinsics</a>
180 <ol>
181 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
182 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
183 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
184 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
185 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
186 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
187 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
188 </ol>
189 </li>
190 <li><a href="#int_libc">Standard C Library Intrinsics</a>
191 <ol>
192 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
193 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
194 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
195 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
196 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]197 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
198 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
199 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]200 </ol>
201 </li>
202 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
203 <ol>
204 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
205 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
206 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
207 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
208 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
209 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
210 </ol>
211 </li>
212 <li><a href="#int_debugger">Debugger intrinsics</a></li>
213 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]214 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]215 <ol>
216 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]217 </ol>
218 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]219 <li><a href="#int_atomics">Atomic intrinsics</a>
220 <ol>
221 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
222 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
223 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
224 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
225 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
226 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
227 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
228 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
229 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
230 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
231 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
232 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
233 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
234 </ol>
235 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]236 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]237 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]238 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]239 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]240 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]241 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]242 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]243 '<tt>llvm.trap</tt>' Intrinsic</a></li>
244 <li><a href="#int_stackprotector">
245 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]246 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]247 </li>
248 </ol>
249 </li>
250</ol>
251
252<div class="doc_author">
253 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
254 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
255</div>
256
257<!-- *********************************************************************** -->
258<div class="doc_section"> <a name="abstract">Abstract </a></div>
259<!-- *********************************************************************** -->
260
261<div class="doc_text">
262<p>This document is a reference manual for the LLVM assembly language.
Bill Wendlinge7846a52008-08-05 22:29:16 +0000[diff] [blame]263LLVM is a Static Single Assignment (SSA) based representation that provides
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]264type safety, low-level operations, flexibility, and the capability of
265representing 'all' high-level languages cleanly. It is the common code
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]266representation used throughout all phases of the LLVM compilation
267strategy.</p>
268</div>
269
270<!-- *********************************************************************** -->
271<div class="doc_section"> <a name="introduction">Introduction</a> </div>
272<!-- *********************************************************************** -->
273
274<div class="doc_text">
275
276<p>The LLVM code representation is designed to be used in three
277different forms: as an in-memory compiler IR, as an on-disk bitcode
278representation (suitable for fast loading by a Just-In-Time compiler),
279and as a human readable assembly language representation. This allows
280LLVM to provide a powerful intermediate representation for efficient
281compiler transformations and analysis, while providing a natural means
282to debug and visualize the transformations. The three different forms
283of LLVM are all equivalent. This document describes the human readable
284representation and notation.</p>
285
286<p>The LLVM representation aims to be light-weight and low-level
287while being expressive, typed, and extensible at the same time. It
288aims to be a "universal IR" of sorts, by being at a low enough level
289that high-level ideas may be cleanly mapped to it (similar to how
290microprocessors are "universal IR's", allowing many source languages to
291be mapped to them). By providing type information, LLVM can be used as
292the target of optimizations: for example, through pointer analysis, it
293can be proven that a C automatic variable is never accessed outside of
294the current function... allowing it to be promoted to a simple SSA
295value instead of a memory location.</p>
296
297</div>
298
299<!-- _______________________________________________________________________ -->
300<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
301
302<div class="doc_text">
303
304<p>It is important to note that this document describes 'well formed'
305LLVM assembly language. There is a difference between what the parser
306accepts and what is considered 'well formed'. For example, the
307following instruction is syntactically okay, but not well formed:</p>
308
309<div class="doc_code">
310<pre>
311%x = <a href="#i_add">add</a> i32 1, %x
312</pre>
313</div>
314
315<p>...because the definition of <tt>%x</tt> does not dominate all of
316its uses. The LLVM infrastructure provides a verification pass that may
317be used to verify that an LLVM module is well formed. This pass is
318automatically run by the parser after parsing input assembly and by
319the optimizer before it outputs bitcode. The violations pointed out
320by the verifier pass indicate bugs in transformation passes or input to
321the parser.</p>
322</div>
323
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]324<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]325
326<!-- *********************************************************************** -->
327<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
328<!-- *********************************************************************** -->
329
330<div class="doc_text">
331
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]332 <p>LLVM identifiers come in two basic types: global and local. Global
333 identifiers (functions, global variables) begin with the @ character. Local
334 identifiers (register names, types) begin with the % character. Additionally,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]335 there are three different formats for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]336
337<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]338 <li>Named values are represented as a string of characters with their prefix.
339 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
340 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]341 Identifiers which require other characters in their names can be surrounded
Daniel Dunbar73f9a772008-10-14 23:51:43 +0000[diff] [blame]342 with quotes. Special characters may be escaped using "\xx" where xx is the
343 ASCII code for the character in hexadecimal. In this way, any character can
344 be used in a name value, even quotes themselves.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]345
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]346 <li>Unnamed values are represented as an unsigned numeric value with their
347 prefix. For example, %12, @2, %44.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]348
349 <li>Constants, which are described in a <a href="#constants">section about
350 constants</a>, below.</li>
351</ol>
352
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]353<p>LLVM requires that values start with a prefix for two reasons: Compilers
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]354don't need to worry about name clashes with reserved words, and the set of
355reserved words may be expanded in the future without penalty. Additionally,
356unnamed identifiers allow a compiler to quickly come up with a temporary
357variable without having to avoid symbol table conflicts.</p>
358
359<p>Reserved words in LLVM are very similar to reserved words in other
360languages. There are keywords for different opcodes
361('<tt><a href="#i_add">add</a></tt>',
362 '<tt><a href="#i_bitcast">bitcast</a></tt>',
363 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
364href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
365and others. These reserved words cannot conflict with variable names, because
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]366none of them start with a prefix character ('%' or '@').</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]367
368<p>Here is an example of LLVM code to multiply the integer variable
369'<tt>%X</tt>' by 8:</p>
370
371<p>The easy way:</p>
372
373<div class="doc_code">
374<pre>
375%result = <a href="#i_mul">mul</a> i32 %X, 8
376</pre>
377</div>
378
379<p>After strength reduction:</p>
380
381<div class="doc_code">
382<pre>
383%result = <a href="#i_shl">shl</a> i32 %X, i8 3
384</pre>
385</div>
386
387<p>And the hard way:</p>
388
389<div class="doc_code">
390<pre>
391<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
392<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
393%result = <a href="#i_add">add</a> i32 %1, %1
394</pre>
395</div>
396
397<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
398important lexical features of LLVM:</p>
399
400<ol>
401
402 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
403 line.</li>
404
405 <li>Unnamed temporaries are created when the result of a computation is not
406 assigned to a named value.</li>
407
408 <li>Unnamed temporaries are numbered sequentially</li>
409
410</ol>
411
412<p>...and it also shows a convention that we follow in this document. When
413demonstrating instructions, we will follow an instruction with a comment that
414defines the type and name of value produced. Comments are shown in italic
415text.</p>
416
417</div>
418
419<!-- *********************************************************************** -->
420<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
421<!-- *********************************************************************** -->
422
423<!-- ======================================================================= -->
424<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
425</div>
426
427<div class="doc_text">
428
429<p>LLVM programs are composed of "Module"s, each of which is a
430translation unit of the input programs. Each module consists of
431functions, global variables, and symbol table entries. Modules may be
432combined together with the LLVM linker, which merges function (and
433global variable) definitions, resolves forward declarations, and merges
434symbol table entries. Here is an example of the "hello world" module:</p>
435
436<div class="doc_code">
437<pre><i>; Declare the string constant as a global constant...</i>
438<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
439 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
440
441<i>; External declaration of the puts function</i>
442<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
443
444<i>; Definition of main function</i>
445define i32 @main() { <i>; i32()* </i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]446 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]447 %cast210 = <a
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]448 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]449
450 <i>; Call puts function to write out the string to stdout...</i>
451 <a
452 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
453 <a
454 href="#i_ret">ret</a> i32 0<br>}<br>
455</pre>
456</div>
457
458<p>This example is made up of a <a href="#globalvars">global variable</a>
459named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
460function, and a <a href="#functionstructure">function definition</a>
461for "<tt>main</tt>".</p>
462
463<p>In general, a module is made up of a list of global values,
464where both functions and global variables are global values. Global values are
465represented by a pointer to a memory location (in this case, a pointer to an
466array of char, and a pointer to a function), and have one of the following <a
467href="#linkage">linkage types</a>.</p>
468
469</div>
470
471<!-- ======================================================================= -->
472<div class="doc_subsection">
473 <a name="linkage">Linkage Types</a>
474</div>
475
476<div class="doc_text">
477
478<p>
479All Global Variables and Functions have one of the following types of linkage:
480</p>
481
482<dl>
483
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]484 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
485
486 <dd>Global values with private linkage are only directly accessible by
487 objects in the current module. In particular, linking code into a module with
488 an private global value may cause the private to be renamed as necessary to
489 avoid collisions. Because the symbol is private to the module, all
490 references can be updated. This doesn't show up in any symbol table in the
491 object file.
492 </dd>
493
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]494 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]495
Duncan Sandsa75223a2009-01-16 09:29:46 +0000[diff] [blame]496 <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]497 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]498 '<tt>static</tt>' keyword in C.
499 </dd>
500
501 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
502
503 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
504 the same name when linkage occurs. This is typically used to implement
505 inline functions, templates, or other code which must be generated in each
506 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
507 allowed to be discarded.
508 </dd>
509
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]510 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
511
512 <dd>"<tt>common</tt>" linkage is exactly the same as <tt>linkonce</tt>
513 linkage, except that unreferenced <tt>common</tt> globals may not be
514 discarded. This is used for globals that may be emitted in multiple
515 translation units, but that are not guaranteed to be emitted into every
516 translation unit that uses them. One example of this is tentative
517 definitions in C, such as "<tt>int X;</tt>" at global scope.
518 </dd>
519
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]520 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
521
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]522 <dd>"<tt>weak</tt>" linkage is the same as <tt>common</tt> linkage, except
523 that some targets may choose to emit different assembly sequences for them
524 for target-dependent reasons. This is used for globals that are declared
525 "weak" in C source code.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]526 </dd>
527
528 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
529
530 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
531 pointer to array type. When two global variables with appending linkage are
532 linked together, the two global arrays are appended together. This is the
533 LLVM, typesafe, equivalent of having the system linker append together
534 "sections" with identical names when .o files are linked.
535 </dd>
536
537 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]538 <dd>The semantics of this linkage follow the ELF object file model: the
539 symbol is weak until linked, if not linked, the symbol becomes null instead
540 of being an undefined reference.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]541 </dd>
542
543 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
544
545 <dd>If none of the above identifiers are used, the global is externally
546 visible, meaning that it participates in linkage and can be used to resolve
547 external symbol references.
548 </dd>
549</dl>
550
551 <p>
552 The next two types of linkage are targeted for Microsoft Windows platform
553 only. They are designed to support importing (exporting) symbols from (to)
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]554 DLLs (Dynamic Link Libraries).
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]555 </p>
556
557 <dl>
558 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
559
560 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
561 or variable via a global pointer to a pointer that is set up by the DLL
562 exporting the symbol. On Microsoft Windows targets, the pointer name is
Dan Gohman5ec99832009-01-12 21:35:55 +0000[diff] [blame]563 formed by combining <code>__imp_</code> and the function or variable name.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]564 </dd>
565
566 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
567
568 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
569 pointer to a pointer in a DLL, so that it can be referenced with the
570 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
Dan Gohman5ec99832009-01-12 21:35:55 +0000[diff] [blame]571 name is formed by combining <code>__imp_</code> and the function or variable
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]572 name.
573 </dd>
574
575</dl>
576
Dan Gohman4dfac702008-11-24 17:18:39 +0000[diff] [blame]577<p>For example, since the "<tt>.LC0</tt>"
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]578variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
579variable and was linked with this one, one of the two would be renamed,
580preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
581external (i.e., lacking any linkage declarations), they are accessible
582outside of the current module.</p>
583<p>It is illegal for a function <i>declaration</i>
584to have any linkage type other than "externally visible", <tt>dllimport</tt>,
585or <tt>extern_weak</tt>.</p>
586<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]587linkages.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]588</div>
589
590<!-- ======================================================================= -->
591<div class="doc_subsection">
592 <a name="callingconv">Calling Conventions</a>
593</div>
594
595<div class="doc_text">
596
597<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
598and <a href="#i_invoke">invokes</a> can all have an optional calling convention
599specified for the call. The calling convention of any pair of dynamic
600caller/callee must match, or the behavior of the program is undefined. The
601following calling conventions are supported by LLVM, and more may be added in
602the future:</p>
603
604<dl>
605 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
606
607 <dd>This calling convention (the default if no other calling convention is
608 specified) matches the target C calling conventions. This calling convention
609 supports varargs function calls and tolerates some mismatch in the declared
610 prototype and implemented declaration of the function (as does normal C).
611 </dd>
612
613 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
614
615 <dd>This calling convention attempts to make calls as fast as possible
616 (e.g. by passing things in registers). This calling convention allows the
617 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]618 without having to conform to an externally specified ABI (Application Binary
619 Interface). Implementations of this convention should allow arbitrary
Arnold Schwaighofer07444922008-05-14 09:17:12 +0000[diff] [blame]620 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> to be
621 supported. This calling convention does not support varargs and requires the
622 prototype of all callees to exactly match the prototype of the function
623 definition.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]624 </dd>
625
626 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
627
628 <dd>This calling convention attempts to make code in the caller as efficient
629 as possible under the assumption that the call is not commonly executed. As
630 such, these calls often preserve all registers so that the call does not break
631 any live ranges in the caller side. This calling convention does not support
632 varargs and requires the prototype of all callees to exactly match the
633 prototype of the function definition.
634 </dd>
635
636 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
637
638 <dd>Any calling convention may be specified by number, allowing
639 target-specific calling conventions to be used. Target specific calling
640 conventions start at 64.
641 </dd>
642</dl>
643
644<p>More calling conventions can be added/defined on an as-needed basis, to
645support pascal conventions or any other well-known target-independent
646convention.</p>
647
648</div>
649
650<!-- ======================================================================= -->
651<div class="doc_subsection">
652 <a name="visibility">Visibility Styles</a>
653</div>
654
655<div class="doc_text">
656
657<p>
658All Global Variables and Functions have one of the following visibility styles:
659</p>
660
661<dl>
662 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
663
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]664 <dd>On targets that use the ELF object file format, default visibility means
665 that the declaration is visible to other
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]666 modules and, in shared libraries, means that the declared entity may be
667 overridden. On Darwin, default visibility means that the declaration is
668 visible to other modules. Default visibility corresponds to "external
669 linkage" in the language.
670 </dd>
671
672 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
673
674 <dd>Two declarations of an object with hidden visibility refer to the same
675 object if they are in the same shared object. Usually, hidden visibility
676 indicates that the symbol will not be placed into the dynamic symbol table,
677 so no other module (executable or shared library) can reference it
678 directly.
679 </dd>
680
681 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
682
683 <dd>On ELF, protected visibility indicates that the symbol will be placed in
684 the dynamic symbol table, but that references within the defining module will
685 bind to the local symbol. That is, the symbol cannot be overridden by another
686 module.
687 </dd>
688</dl>
689
690</div>
691
692<!-- ======================================================================= -->
693<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]694 <a name="namedtypes">Named Types</a>
695</div>
696
697<div class="doc_text">
698
699<p>LLVM IR allows you to specify name aliases for certain types. This can make
700it easier to read the IR and make the IR more condensed (particularly when
701recursive types are involved). An example of a name specification is:
702</p>
703
704<div class="doc_code">
705<pre>
706%mytype = type { %mytype*, i32 }
707</pre>
708</div>
709
710<p>You may give a name to any <a href="#typesystem">type</a> except "<a
711href="t_void">void</a>". Type name aliases may be used anywhere a type is
712expected with the syntax "%mytype".</p>
713
714<p>Note that type names are aliases for the structural type that they indicate,
715and that you can therefore specify multiple names for the same type. This often
716leads to confusing behavior when dumping out a .ll file. Since LLVM IR uses
717structural typing, the name is not part of the type. When printing out LLVM IR,
718the printer will pick <em>one name</em> to render all types of a particular
719shape. This means that if you have code where two different source types end up
720having the same LLVM type, that the dumper will sometimes print the "wrong" or
721unexpected type. This is an important design point and isn't going to
722change.</p>
723
724</div>
725
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]726<!-- ======================================================================= -->
727<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]728 <a name="globalvars">Global Variables</a>
729</div>
730
731<div class="doc_text">
732
733<p>Global variables define regions of memory allocated at compilation time
734instead of run-time. Global variables may optionally be initialized, may have
735an explicit section to be placed in, and may have an optional explicit alignment
736specified. A variable may be defined as "thread_local", which means that it
737will not be shared by threads (each thread will have a separated copy of the
738variable). A variable may be defined as a global "constant," which indicates
739that the contents of the variable will <b>never</b> be modified (enabling better
740optimization, allowing the global data to be placed in the read-only section of
741an executable, etc). Note that variables that need runtime initialization
742cannot be marked "constant" as there is a store to the variable.</p>
743
744<p>
745LLVM explicitly allows <em>declarations</em> of global variables to be marked
746constant, even if the final definition of the global is not. This capability
747can be used to enable slightly better optimization of the program, but requires
748the language definition to guarantee that optimizations based on the
749'constantness' are valid for the translation units that do not include the
750definition.
751</p>
752
753<p>As SSA values, global variables define pointer values that are in
754scope (i.e. they dominate) all basic blocks in the program. Global
755variables always define a pointer to their "content" type because they
756describe a region of memory, and all memory objects in LLVM are
757accessed through pointers.</p>
758
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]759<p>A global variable may be declared to reside in a target-specifc numbered
760address space. For targets that support them, address spaces may affect how
761optimizations are performed and/or what target instructions are used to access
Christopher Lamb20a39e92007-12-12 08:44:39 +0000[diff] [blame]762the variable. The default address space is zero. The address space qualifier
763must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]764
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]765<p>LLVM allows an explicit section to be specified for globals. If the target
766supports it, it will emit globals to the section specified.</p>
767
768<p>An explicit alignment may be specified for a global. If not present, or if
769the alignment is set to zero, the alignment of the global is set by the target
770to whatever it feels convenient. If an explicit alignment is specified, the
771global is forced to have at least that much alignment. All alignments must be
772a power of 2.</p>
773
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]774<p>For example, the following defines a global in a numbered address space with
775an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]776
777<div class="doc_code">
778<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]779@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]780</pre>
781</div>
782
783</div>
784
785
786<!-- ======================================================================= -->
787<div class="doc_subsection">
788 <a name="functionstructure">Functions</a>
789</div>
790
791<div class="doc_text">
792
793<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
794an optional <a href="#linkage">linkage type</a>, an optional
795<a href="#visibility">visibility style</a>, an optional
796<a href="#callingconv">calling convention</a>, a return type, an optional
797<a href="#paramattrs">parameter attribute</a> for the return type, a function
798name, a (possibly empty) argument list (each with optional
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]799<a href="#paramattrs">parameter attributes</a>), optional
800<a href="#fnattrs">function attributes</a>, an optional section,
801an optional alignment, an optional <a href="#gc">garbage collector name</a>,
Chris Lattneree202542008-10-04 18:10:21 +0000[diff] [blame]802an opening curly brace, a list of basic blocks, and a closing curly brace.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]803
804LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
805optional <a href="#linkage">linkage type</a>, an optional
806<a href="#visibility">visibility style</a>, an optional
807<a href="#callingconv">calling convention</a>, a return type, an optional
808<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]809name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksend606f5b2007-12-10 03:30:21 +0000[diff] [blame]810<a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]811
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]812<p>A function definition contains a list of basic blocks, forming the CFG
813(Control Flow Graph) for
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]814the function. Each basic block may optionally start with a label (giving the
815basic block a symbol table entry), contains a list of instructions, and ends
816with a <a href="#terminators">terminator</a> instruction (such as a branch or
817function return).</p>
818
819<p>The first basic block in a function is special in two ways: it is immediately
820executed on entrance to the function, and it is not allowed to have predecessor
821basic blocks (i.e. there can not be any branches to the entry block of a
822function). Because the block can have no predecessors, it also cannot have any
823<a href="#i_phi">PHI nodes</a>.</p>
824
825<p>LLVM allows an explicit section to be specified for functions. If the target
826supports it, it will emit functions to the section specified.</p>
827
828<p>An explicit alignment may be specified for a function. If not present, or if
829the alignment is set to zero, the alignment of the function is set by the target
830to whatever it feels convenient. If an explicit alignment is specified, the
831function is forced to have at least that much alignment. All alignments must be
832a power of 2.</p>
833
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]834 <h5>Syntax:</h5>
835
836<div class="doc_code">
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]837<tt>
838define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
839 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
840 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
841 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
842 [<a href="#gc">gc</a>] { ... }
843</tt>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]844</div>
845
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]846</div>
847
848
849<!-- ======================================================================= -->
850<div class="doc_subsection">
851 <a name="aliasstructure">Aliases</a>
852</div>
853<div class="doc_text">
854 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikov96822812008-03-22 08:36:14 +0000[diff] [blame]855 function, global variable, another alias or bitcast of global value). Aliases
856 may have an optional <a href="#linkage">linkage type</a>, and an
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]857 optional <a href="#visibility">visibility style</a>.</p>
858
859 <h5>Syntax:</h5>
860
861<div class="doc_code">
862<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]863@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]864</pre>
865</div>
866
867</div>
868
869
870
871<!-- ======================================================================= -->
872<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
873<div class="doc_text">
874 <p>The return type and each parameter of a function type may have a set of
875 <i>parameter attributes</i> associated with them. Parameter attributes are
876 used to communicate additional information about the result or parameters of
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]877 a function. Parameter attributes are considered to be part of the function,
878 not of the function type, so functions with different parameter attributes
879 can have the same function type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]880
881 <p>Parameter attributes are simple keywords that follow the type specified. If
882 multiple parameter attributes are needed, they are space separated. For
883 example:</p>
884
885<div class="doc_code">
886<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]887declare i32 @printf(i8* noalias , ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]888declare i32 @atoi(i8 zeroext)
889declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]890</pre>
891</div>
892
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]893 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
894 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]895
896 <p>Currently, only the following parameter attributes are defined:</p>
897 <dl>
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]898 <dt><tt>zeroext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]899 <dd>This indicates to the code generator that the parameter or return value
900 should be zero-extended to a 32-bit value by the caller (for a parameter)
901 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]902
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]903 <dt><tt>signext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]904 <dd>This indicates to the code generator that the parameter or return value
905 should be sign-extended to a 32-bit value by the caller (for a parameter)
906 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]907
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]908 <dt><tt>inreg</tt></dt>
Dale Johannesenc08a0e22008-09-25 20:47:45 +0000[diff] [blame]909 <dd>This indicates that this parameter or return value should be treated
910 in a special target-dependent fashion during while emitting code for a
911 function call or return (usually, by putting it in a register as opposed
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]912 to memory, though some targets use it to distinguish between two different
913 kinds of registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]914
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]915 <dt><tt><a name="byval">byval</a></tt></dt>
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]916 <dd>This indicates that the pointer parameter should really be passed by
917 value to the function. The attribute implies that a hidden copy of the
918 pointee is made between the caller and the callee, so the callee is unable
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]919 to modify the value in the callee. This attribute is only valid on LLVM
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]920 pointer arguments. It is generally used to pass structs and arrays by
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]921 value, but is also valid on pointers to scalars. The copy is considered to
922 belong to the caller not the callee (for example,
923 <tt><a href="#readonly">readonly</a></tt> functions should not write to
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]924 <tt>byval</tt> parameters). This is not a valid attribute for return
925 values. </dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]926
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]927 <dt><tt>sret</tt></dt>
Duncan Sands616cc032008-02-18 04:19:38 +0000[diff] [blame]928 <dd>This indicates that the pointer parameter specifies the address of a
929 structure that is the return value of the function in the source program.
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]930 This pointer must be guaranteed by the caller to be valid: loads and stores
931 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]932 be applied to the first parameter. This is not a valid attribute for
933 return values. </dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]934
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]935 <dt><tt>noalias</tt></dt>
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]936 <dd>This indicates that the pointer does not alias any global or any other
937 parameter. The caller is responsible for ensuring that this is the
Nick Lewyckya604a942008-11-24 05:00:44 +0000[diff] [blame]938 case. On a function return value, <tt>noalias</tt> additionally indicates
939 that the pointer does not alias any other pointers visible to the
Nick Lewycky40fb6f22008-12-19 06:39:12 +0000[diff] [blame]940 caller. For further details, please see the discussion of the NoAlias
941 response in
942 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
943 analysis</a>.</dd>
944
945 <dt><tt>nocapture</tt></dt>
946 <dd>This indicates that the callee does not make any copies of the pointer
947 that outlive the callee itself. This is not a valid attribute for return
948 values.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]949
Duncan Sands4ee46812007-07-27 19:57:41 +0000[diff] [blame]950 <dt><tt>nest</tt></dt>
Duncan Sandsf1a7d4c2008-07-08 09:27:25 +0000[diff] [blame]951 <dd>This indicates that the pointer parameter can be excised using the
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]952 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
953 attribute for return values.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]954 </dl>
955
956</div>
957
958<!-- ======================================================================= -->
959<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]960 <a name="gc">Garbage Collector Names</a>
961</div>
962
963<div class="doc_text">
964<p>Each function may specify a garbage collector name, which is simply a
965string.</p>
966
967<div class="doc_code"><pre
968>define void @f() gc "name" { ...</pre></div>
969
970<p>The compiler declares the supported values of <i>name</i>. Specifying a
971collector which will cause the compiler to alter its output in order to support
972the named garbage collection algorithm.</p>
973</div>
974
975<!-- ======================================================================= -->
976<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]977 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]978</div>
979
980<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]981
982<p>Function attributes are set to communicate additional information about
983 a function. Function attributes are considered to be part of the function,
984 not of the function type, so functions with different parameter attributes
985 can have the same function type.</p>
986
987 <p>Function attributes are simple keywords that follow the type specified. If
988 multiple attributes are needed, they are space separated. For
989 example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]990
991<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]992<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]993define void @f() noinline { ... }
994define void @f() alwaysinline { ... }
995define void @f() alwaysinline optsize { ... }
996define void @f() optsize
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]997</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]998</div>
999
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1000<dl>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1001<dt><tt>alwaysinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1002<dd>This attribute indicates that the inliner should attempt to inline this
1003function into callers whenever possible, ignoring any active inlining size
1004threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1005
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1006<dt><tt>noinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1007<dd>This attribute indicates that the inliner should never inline this function
Chris Lattner377f3ae2008-10-05 17:14:59 +0000[diff] [blame]1008in any situation. This attribute may not be used together with the
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1009<tt>alwaysinline</tt> attribute.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1010
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1011<dt><tt>optsize</tt></dt>
Devang Patelc29099b2008-09-29 18:34:44 +0000[diff] [blame]1012<dd>This attribute suggests that optimization passes and code generator passes
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1013make choices that keep the code size of this function low, and otherwise do
1014optimizations specifically to reduce code size.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1015
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1016<dt><tt>noreturn</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1017<dd>This function attribute indicates that the function never returns normally.
1018This produces undefined behavior at runtime if the function ever does
1019dynamically return.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1020
1021<dt><tt>nounwind</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1022<dd>This function attribute indicates that the function never returns with an
1023unwind or exceptional control flow. If the function does unwind, its runtime
1024behavior is undefined.</dd>
1025
1026<dt><tt>readnone</tt></dt>
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]1027<dd>This attribute indicates that the function computes its result (or the
1028exception it throws) based strictly on its arguments, without dereferencing any
1029pointer arguments or otherwise accessing any mutable state (e.g. memory, control
1030registers, etc) visible to caller functions. It does not write through any
1031pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments) and
1032never changes any state visible to callers.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1033
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]1034<dt><tt><a name="readonly">readonly</a></tt></dt>
1035<dd>This attribute indicates that the function does not write through any
1036pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments)
1037or otherwise modify any state (e.g. memory, control registers, etc) visible to
1038caller functions. It may dereference pointer arguments and read state that may
1039be set in the caller. A readonly function always returns the same value (or
1040throws the same exception) when called with the same set of arguments and global
1041state.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1042
1043<dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1044<dd>This attribute indicates that the function should emit a stack smashing
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1045protector. It is in the form of a "canary"&mdash;a random value placed on the
1046stack before the local variables that's checked upon return from the function to
1047see if it has been overwritten. A heuristic is used to determine if a function
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1048needs stack protectors or not.
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1049
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1050<p>If a function that has an <tt>ssp</tt> attribute is inlined into a function
1051that doesn't have an <tt>ssp</tt> attribute, then the resulting function will
1052have an <tt>ssp</tt> attribute.</p></dd>
1053
1054<dt><tt>sspreq</tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1055<dd>This attribute indicates that the function should <em>always</em> emit a
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1056stack smashing protector. This overrides the <tt><a href="#ssp">ssp</a></tt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1057function attribute.
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1058
1059<p>If a function that has an <tt>sspreq</tt> attribute is inlined into a
1060function that doesn't have an <tt>sspreq</tt> attribute or which has
1061an <tt>ssp</tt> attribute, then the resulting function will have
1062an <tt>sspreq</tt> attribute.</p></dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1063</dl>
1064
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1065</div>
1066
1067<!-- ======================================================================= -->
1068<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1069 <a name="moduleasm">Module-Level Inline Assembly</a>
1070</div>
1071
1072<div class="doc_text">
1073<p>
1074Modules may contain "module-level inline asm" blocks, which corresponds to the
1075GCC "file scope inline asm" blocks. These blocks are internally concatenated by
1076LLVM and treated as a single unit, but may be separated in the .ll file if
1077desired. The syntax is very simple:
1078</p>
1079
1080<div class="doc_code">
1081<pre>
1082module asm "inline asm code goes here"
1083module asm "more can go here"
1084</pre>
1085</div>
1086
1087<p>The strings can contain any character by escaping non-printable characters.
1088 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
1089 for the number.
1090</p>
1091
1092<p>
1093 The inline asm code is simply printed to the machine code .s file when
1094 assembly code is generated.
1095</p>
1096</div>
1097
1098<!-- ======================================================================= -->
1099<div class="doc_subsection">
1100 <a name="datalayout">Data Layout</a>
1101</div>
1102
1103<div class="doc_text">
1104<p>A module may specify a target specific data layout string that specifies how
1105data is to be laid out in memory. The syntax for the data layout is simply:</p>
1106<pre> target datalayout = "<i>layout specification</i>"</pre>
1107<p>The <i>layout specification</i> consists of a list of specifications
1108separated by the minus sign character ('-'). Each specification starts with a
1109letter and may include other information after the letter to define some
1110aspect of the data layout. The specifications accepted are as follows: </p>
1111<dl>
1112 <dt><tt>E</tt></dt>
1113 <dd>Specifies that the target lays out data in big-endian form. That is, the
1114 bits with the most significance have the lowest address location.</dd>
1115 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1116 <dd>Specifies that the target lays out data in little-endian form. That is,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1117 the bits with the least significance have the lowest address location.</dd>
1118 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1119 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
1120 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
1121 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
1122 too.</dd>
1123 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1124 <dd>This specifies the alignment for an integer type of a given bit
1125 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1126 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1127 <dd>This specifies the alignment for a vector type of a given bit
1128 <i>size</i>.</dd>
1129 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1130 <dd>This specifies the alignment for a floating point type of a given bit
1131 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1132 (double).</dd>
1133 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1134 <dd>This specifies the alignment for an aggregate type of a given bit
1135 <i>size</i>.</dd>
1136</dl>
1137<p>When constructing the data layout for a given target, LLVM starts with a
1138default set of specifications which are then (possibly) overriden by the
1139specifications in the <tt>datalayout</tt> keyword. The default specifications
1140are given in this list:</p>
1141<ul>
1142 <li><tt>E</tt> - big endian</li>
1143 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1144 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1145 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1146 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1147 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1148 <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]1149 alignment of 64-bits</li>
1150 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1151 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1152 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1153 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1154 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
1155</ul>
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]1156<p>When LLVM is determining the alignment for a given type, it uses the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1157following rules:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1158<ol>
1159 <li>If the type sought is an exact match for one of the specifications, that
1160 specification is used.</li>
1161 <li>If no match is found, and the type sought is an integer type, then the
1162 smallest integer type that is larger than the bitwidth of the sought type is
1163 used. If none of the specifications are larger than the bitwidth then the the
1164 largest integer type is used. For example, given the default specifications
1165 above, the i7 type will use the alignment of i8 (next largest) while both
1166 i65 and i256 will use the alignment of i64 (largest specified).</li>
1167 <li>If no match is found, and the type sought is a vector type, then the
1168 largest vector type that is smaller than the sought vector type will be used
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1169 as a fall back. This happens because &lt;128 x double&gt; can be implemented
1170 in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1171</ol>
1172</div>
1173
1174<!-- *********************************************************************** -->
1175<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1176<!-- *********************************************************************** -->
1177
1178<div class="doc_text">
1179
1180<p>The LLVM type system is one of the most important features of the
1181intermediate representation. Being typed enables a number of
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1182optimizations to be performed on the intermediate representation directly,
1183without having to do
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1184extra analyses on the side before the transformation. A strong type
1185system makes it easier to read the generated code and enables novel
1186analyses and transformations that are not feasible to perform on normal
1187three address code representations.</p>
1188
1189</div>
1190
1191<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1192<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1193Classifications</a> </div>
1194<div class="doc_text">
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1195<p>The types fall into a few useful
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1196classifications:</p>
1197
1198<table border="1" cellspacing="0" cellpadding="4">
1199 <tbody>
1200 <tr><th>Classification</th><th>Types</th></tr>
1201 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1202 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1203 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1204 </tr>
1205 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1206 <td><a href="#t_floating">floating point</a></td>
1207 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1208 </tr>
1209 <tr>
1210 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1211 <td><a href="#t_integer">integer</a>,
1212 <a href="#t_floating">floating point</a>,
1213 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1214 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1215 <a href="#t_struct">structure</a>,
1216 <a href="#t_array">array</a>,
Dan Gohmand13951e2008-05-23 22:50:26 +0000[diff] [blame]1217 <a href="#t_label">label</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1218 </td>
1219 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1220 <tr>
1221 <td><a href="#t_primitive">primitive</a></td>
1222 <td><a href="#t_label">label</a>,
1223 <a href="#t_void">void</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1224 <a href="#t_floating">floating point</a>.</td>
1225 </tr>
1226 <tr>
1227 <td><a href="#t_derived">derived</a></td>
1228 <td><a href="#t_integer">integer</a>,
1229 <a href="#t_array">array</a>,
1230 <a href="#t_function">function</a>,
1231 <a href="#t_pointer">pointer</a>,
1232 <a href="#t_struct">structure</a>,
1233 <a href="#t_pstruct">packed structure</a>,
1234 <a href="#t_vector">vector</a>,
1235 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1236 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1237 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1238 </tbody>
1239</table>
1240
1241<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1242most important. Values of these types are the only ones which can be
1243produced by instructions, passed as arguments, or used as operands to
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]1244instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1245</div>
1246
1247<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1248<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1249
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1250<div class="doc_text">
1251<p>The primitive types are the fundamental building blocks of the LLVM
1252system.</p>
1253
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1254</div>
1255
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1256<!-- _______________________________________________________________________ -->
1257<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1258
1259<div class="doc_text">
1260 <table>
1261 <tbody>
1262 <tr><th>Type</th><th>Description</th></tr>
1263 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1264 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1265 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1266 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1267 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1268 </tbody>
1269 </table>
1270</div>
1271
1272<!-- _______________________________________________________________________ -->
1273<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1274
1275<div class="doc_text">
1276<h5>Overview:</h5>
1277<p>The void type does not represent any value and has no size.</p>
1278
1279<h5>Syntax:</h5>
1280
1281<pre>
1282 void
1283</pre>
1284</div>
1285
1286<!-- _______________________________________________________________________ -->
1287<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1288
1289<div class="doc_text">
1290<h5>Overview:</h5>
1291<p>The label type represents code labels.</p>
1292
1293<h5>Syntax:</h5>
1294
1295<pre>
1296 label
1297</pre>
1298</div>
1299
1300
1301<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1302<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1303
1304<div class="doc_text">
1305
1306<p>The real power in LLVM comes from the derived types in the system.
1307This is what allows a programmer to represent arrays, functions,
1308pointers, and other useful types. Note that these derived types may be
1309recursive: For example, it is possible to have a two dimensional array.</p>
1310
1311</div>
1312
1313<!-- _______________________________________________________________________ -->
1314<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1315
1316<div class="doc_text">
1317
1318<h5>Overview:</h5>
1319<p>The integer type is a very simple derived type that simply specifies an
1320arbitrary bit width for the integer type desired. Any bit width from 1 bit to
13212^23-1 (about 8 million) can be specified.</p>
1322
1323<h5>Syntax:</h5>
1324
1325<pre>
1326 iN
1327</pre>
1328
1329<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1330value.</p>
1331
1332<h5>Examples:</h5>
1333<table class="layout">
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1334 <tbody>
1335 <tr>
1336 <td><tt>i1</tt></td>
1337 <td>a single-bit integer.</td>
1338 </tr><tr>
1339 <td><tt>i32</tt></td>
1340 <td>a 32-bit integer.</td>
1341 </tr><tr>
1342 <td><tt>i1942652</tt></td>
1343 <td>a really big integer of over 1 million bits.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1344 </tr>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1345 </tbody>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1346</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1347
1348<p>Note that the code generator does not yet support large integer types
1349to be used as function return types. The specific limit on how large a
1350return type the code generator can currently handle is target-dependent;
1351currently it's often 64 bits for 32-bit targets and 128 bits for 64-bit
1352targets.</p>
1353
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1354</div>
1355
1356<!-- _______________________________________________________________________ -->
1357<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1358
1359<div class="doc_text">
1360
1361<h5>Overview:</h5>
1362
1363<p>The array type is a very simple derived type that arranges elements
1364sequentially in memory. The array type requires a size (number of
1365elements) and an underlying data type.</p>
1366
1367<h5>Syntax:</h5>
1368
1369<pre>
1370 [&lt;# elements&gt; x &lt;elementtype&gt;]
1371</pre>
1372
1373<p>The number of elements is a constant integer value; elementtype may
1374be any type with a size.</p>
1375
1376<h5>Examples:</h5>
1377<table class="layout">
1378 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1379 <td class="left"><tt>[40 x i32]</tt></td>
1380 <td class="left">Array of 40 32-bit integer values.</td>
1381 </tr>
1382 <tr class="layout">
1383 <td class="left"><tt>[41 x i32]</tt></td>
1384 <td class="left">Array of 41 32-bit integer values.</td>
1385 </tr>
1386 <tr class="layout">
1387 <td class="left"><tt>[4 x i8]</tt></td>
1388 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1389 </tr>
1390</table>
1391<p>Here are some examples of multidimensional arrays:</p>
1392<table class="layout">
1393 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1394 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1395 <td class="left">3x4 array of 32-bit integer values.</td>
1396 </tr>
1397 <tr class="layout">
1398 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1399 <td class="left">12x10 array of single precision floating point values.</td>
1400 </tr>
1401 <tr class="layout">
1402 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1403 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1404 </tr>
1405</table>
1406
1407<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1408length array. Normally, accesses past the end of an array are undefined in
1409LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1410As a special case, however, zero length arrays are recognized to be variable
1411length. This allows implementation of 'pascal style arrays' with the LLVM
1412type "{ i32, [0 x float]}", for example.</p>
1413
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1414<p>Note that the code generator does not yet support large aggregate types
1415to be used as function return types. The specific limit on how large an
1416aggregate return type the code generator can currently handle is
1417target-dependent, and also dependent on the aggregate element types.</p>
1418
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1419</div>
1420
1421<!-- _______________________________________________________________________ -->
1422<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
1423<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1424
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1425<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1426
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1427<p>The function type can be thought of as a function signature. It
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1428consists of a return type and a list of formal parameter types. The
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1429return 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]1430If 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]1431class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1432
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1433<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1434
1435<pre>
1436 &lt;returntype list&gt; (&lt;parameter list&gt;)
1437</pre>
1438
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1439<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
1440specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1441which indicates that the function takes a variable number of arguments.
1442Variable argument functions can access their arguments with the <a
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1443 href="#int_varargs">variable argument handling intrinsic</a> functions.
1444'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1445<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1446
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1447<h5>Examples:</h5>
1448<table class="layout">
1449 <tr class="layout">
1450 <td class="left"><tt>i32 (i32)</tt></td>
1451 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1452 </td>
1453 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1454 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1455 </tt></td>
1456 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1457 an <tt>i16</tt> that should be sign extended and a
1458 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1459 <tt>float</tt>.
1460 </td>
1461 </tr><tr class="layout">
1462 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1463 <td class="left">A vararg function that takes at least one
1464 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1465 which returns an integer. This is the signature for <tt>printf</tt> in
1466 LLVM.
1467 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1468 </tr><tr class="layout">
1469 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Misha Brukmanafc88b02008-11-27 06:41:20 +0000[diff] [blame]1470 <td class="left">A function taking an <tt>i32</tt>, returning two
1471 <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1472 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1473 </tr>
1474</table>
1475
1476</div>
1477<!-- _______________________________________________________________________ -->
1478<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
1479<div class="doc_text">
1480<h5>Overview:</h5>
1481<p>The structure type is used to represent a collection of data members
1482together in memory. The packing of the field types is defined to match
1483the ABI of the underlying processor. The elements of a structure may
1484be any type that has a size.</p>
1485<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1486and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1487field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1488instruction.</p>
1489<h5>Syntax:</h5>
1490<pre> { &lt;type list&gt; }<br></pre>
1491<h5>Examples:</h5>
1492<table class="layout">
1493 <tr class="layout">
1494 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1495 <td class="left">A triple of three <tt>i32</tt> values</td>
1496 </tr><tr class="layout">
1497 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1498 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1499 second element is a <a href="#t_pointer">pointer</a> to a
1500 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1501 an <tt>i32</tt>.</td>
1502 </tr>
1503</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1504
1505<p>Note that the code generator does not yet support large aggregate types
1506to be used as function return types. The specific limit on how large an
1507aggregate return type the code generator can currently handle is
1508target-dependent, and also dependent on the aggregate element types.</p>
1509
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1510</div>
1511
1512<!-- _______________________________________________________________________ -->
1513<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1514</div>
1515<div class="doc_text">
1516<h5>Overview:</h5>
1517<p>The packed structure type is used to represent a collection of data members
1518together in memory. There is no padding between fields. Further, the alignment
1519of a packed structure is 1 byte. The elements of a packed structure may
1520be any type that has a size.</p>
1521<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1522and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1523field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1524instruction.</p>
1525<h5>Syntax:</h5>
1526<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1527<h5>Examples:</h5>
1528<table class="layout">
1529 <tr class="layout">
1530 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1531 <td class="left">A triple of three <tt>i32</tt> values</td>
1532 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1533 <td class="left">
1534<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1535 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1536 second element is a <a href="#t_pointer">pointer</a> to a
1537 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1538 an <tt>i32</tt>.</td>
1539 </tr>
1540</table>
1541</div>
1542
1543<!-- _______________________________________________________________________ -->
1544<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
1545<div class="doc_text">
1546<h5>Overview:</h5>
1547<p>As in many languages, the pointer type represents a pointer or
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]1548reference to another object, which must live in memory. Pointer types may have
1549an optional address space attribute defining the target-specific numbered
1550address space where the pointed-to object resides. The default address space is
1551zero.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1552<h5>Syntax:</h5>
1553<pre> &lt;type&gt; *<br></pre>
1554<h5>Examples:</h5>
1555<table class="layout">
1556 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1557 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1558 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1559 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1560 </tr>
1561 <tr class="layout">
1562 <td class="left"><tt>i32 (i32 *) *</tt></td>
1563 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1564 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1565 <tt>i32</tt>.</td>
1566 </tr>
1567 <tr class="layout">
1568 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1569 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1570 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1571 </tr>
1572</table>
1573</div>
1574
1575<!-- _______________________________________________________________________ -->
1576<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
1577<div class="doc_text">
1578
1579<h5>Overview:</h5>
1580
1581<p>A vector type is a simple derived type that represents a vector
1582of elements. Vector types are used when multiple primitive data
1583are operated in parallel using a single instruction (SIMD).
1584A vector type requires a size (number of
1585elements) and an underlying primitive data type. Vectors must have a power
1586of two length (1, 2, 4, 8, 16 ...). Vector types are
1587considered <a href="#t_firstclass">first class</a>.</p>
1588
1589<h5>Syntax:</h5>
1590
1591<pre>
1592 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1593</pre>
1594
1595<p>The number of elements is a constant integer value; elementtype may
1596be any integer or floating point type.</p>
1597
1598<h5>Examples:</h5>
1599
1600<table class="layout">
1601 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1602 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1603 <td class="left">Vector of 4 32-bit integer values.</td>
1604 </tr>
1605 <tr class="layout">
1606 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1607 <td class="left">Vector of 8 32-bit floating-point values.</td>
1608 </tr>
1609 <tr class="layout">
1610 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1611 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1612 </tr>
1613</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1614
1615<p>Note that the code generator does not yet support large vector types
1616to be used as function return types. The specific limit on how large a
1617vector return type codegen can currently handle is target-dependent;
1618currently it's often a few times longer than a hardware vector register.</p>
1619
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1620</div>
1621
1622<!-- _______________________________________________________________________ -->
1623<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1624<div class="doc_text">
1625
1626<h5>Overview:</h5>
1627
1628<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksenda0706e2007-10-14 00:34:53 +0000[diff] [blame]1629corresponds (for example) to the C notion of a forward declared structure type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1630In LLVM, opaque types can eventually be resolved to any type (not just a
1631structure type).</p>
1632
1633<h5>Syntax:</h5>
1634
1635<pre>
1636 opaque
1637</pre>
1638
1639<h5>Examples:</h5>
1640
1641<table class="layout">
1642 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1643 <td class="left"><tt>opaque</tt></td>
1644 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1645 </tr>
1646</table>
1647</div>
1648
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1649<!-- ======================================================================= -->
1650<div class="doc_subsection">
1651 <a name="t_uprefs">Type Up-references</a>
1652</div>
1653
1654<div class="doc_text">
1655<h5>Overview:</h5>
1656<p>
1657An "up reference" allows you to refer to a lexically enclosing type without
1658requiring it to have a name. For instance, a structure declaration may contain a
1659pointer to any of the types it is lexically a member of. Example of up
1660references (with their equivalent as named type declarations) include:</p>
1661
1662<pre>
1663 { \2 * } %x = type { %t* }
1664 { \2 }* %y = type { %y }*
1665 \1* %z = type %z*
1666</pre>
1667
1668<p>
1669An up reference is needed by the asmprinter for printing out cyclic types when
1670there is no declared name for a type in the cycle. Because the asmprinter does
1671not want to print out an infinite type string, it needs a syntax to handle
1672recursive types that have no names (all names are optional in llvm IR).
1673</p>
1674
1675<h5>Syntax:</h5>
1676<pre>
1677 \&lt;level&gt;
1678</pre>
1679
1680<p>
1681The level is the count of the lexical type that is being referred to.
1682</p>
1683
1684<h5>Examples:</h5>
1685
1686<table class="layout">
1687 <tr class="layout">
1688 <td class="left"><tt>\1*</tt></td>
1689 <td class="left">Self-referential pointer.</td>
1690 </tr>
1691 <tr class="layout">
1692 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1693 <td class="left">Recursive structure where the upref refers to the out-most
1694 structure.</td>
1695 </tr>
1696</table>
1697</div>
1698
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1699
1700<!-- *********************************************************************** -->
1701<div class="doc_section"> <a name="constants">Constants</a> </div>
1702<!-- *********************************************************************** -->
1703
1704<div class="doc_text">
1705
1706<p>LLVM has several different basic types of constants. This section describes
1707them all and their syntax.</p>
1708
1709</div>
1710
1711<!-- ======================================================================= -->
1712<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1713
1714<div class="doc_text">
1715
1716<dl>
1717 <dt><b>Boolean constants</b></dt>
1718
1719 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1720 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
1721 </dd>
1722
1723 <dt><b>Integer constants</b></dt>
1724
1725 <dd>Standard integers (such as '4') are constants of the <a
1726 href="#t_integer">integer</a> type. Negative numbers may be used with
1727 integer types.
1728 </dd>
1729
1730 <dt><b>Floating point constants</b></dt>
1731
1732 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1733 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]1734 notation (see below). The assembler requires the exact decimal value of
1735 a floating-point constant. For example, the assembler accepts 1.25 but
1736 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1737 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1738
1739 <dt><b>Null pointer constants</b></dt>
1740
1741 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
1742 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1743
1744</dl>
1745
1746<p>The one non-intuitive notation for constants is the optional hexadecimal form
1747of floating point constants. For example, the form '<tt>double
17480x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
17494.5e+15</tt>'. The only time hexadecimal floating point constants are required
1750(and the only time that they are generated by the disassembler) is when a
1751floating point constant must be emitted but it cannot be represented as a
1752decimal floating point number. For example, NaN's, infinities, and other
1753special values are represented in their IEEE hexadecimal format so that
1754assembly and disassembly do not cause any bits to change in the constants.</p>
1755
1756</div>
1757
1758<!-- ======================================================================= -->
1759<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1760</div>
1761
1762<div class="doc_text">
1763<p>Aggregate constants arise from aggregation of simple constants
1764and smaller aggregate constants.</p>
1765
1766<dl>
1767 <dt><b>Structure constants</b></dt>
1768
1769 <dd>Structure constants are represented with notation similar to structure
1770 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner6c8de962007-12-25 20:34:52 +0000[diff] [blame]1771 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1772 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]1773 must have <a href="#t_struct">structure type</a>, and the number and
1774 types of elements must match those specified by the type.
1775 </dd>
1776
1777 <dt><b>Array constants</b></dt>
1778
1779 <dd>Array constants are represented with notation similar to array type
1780 definitions (a comma separated list of elements, surrounded by square brackets
1781 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
1782 constants must have <a href="#t_array">array type</a>, and the number and
1783 types of elements must match those specified by the type.
1784 </dd>
1785
1786 <dt><b>Vector constants</b></dt>
1787
1788 <dd>Vector constants are represented with notation similar to vector type
1789 definitions (a comma separated list of elements, surrounded by
1790 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1791 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
1792 href="#t_vector">vector type</a>, and the number and types of elements must
1793 match those specified by the type.
1794 </dd>
1795
1796 <dt><b>Zero initialization</b></dt>
1797
1798 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1799 value to zero of <em>any</em> type, including scalar and aggregate types.
1800 This is often used to avoid having to print large zero initializers (e.g. for
1801 large arrays) and is always exactly equivalent to using explicit zero
1802 initializers.
1803 </dd>
1804</dl>
1805
1806</div>
1807
1808<!-- ======================================================================= -->
1809<div class="doc_subsection">
1810 <a name="globalconstants">Global Variable and Function Addresses</a>
1811</div>
1812
1813<div class="doc_text">
1814
1815<p>The addresses of <a href="#globalvars">global variables</a> and <a
1816href="#functionstructure">functions</a> are always implicitly valid (link-time)
1817constants. These constants are explicitly referenced when the <a
1818href="#identifiers">identifier for the global</a> is used and always have <a
1819href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1820file:</p>
1821
1822<div class="doc_code">
1823<pre>
1824@X = global i32 17
1825@Y = global i32 42
1826@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
1827</pre>
1828</div>
1829
1830</div>
1831
1832<!-- ======================================================================= -->
1833<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
1834<div class="doc_text">
1835 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
1836 no specific value. Undefined values may be of any type and be used anywhere
1837 a constant is permitted.</p>
1838
1839 <p>Undefined values indicate to the compiler that the program is well defined
1840 no matter what value is used, giving the compiler more freedom to optimize.
1841 </p>
1842</div>
1843
1844<!-- ======================================================================= -->
1845<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1846</div>
1847
1848<div class="doc_text">
1849
1850<p>Constant expressions are used to allow expressions involving other constants
1851to be used as constants. Constant expressions may be of any <a
1852href="#t_firstclass">first class</a> type and may involve any LLVM operation
1853that does not have side effects (e.g. load and call are not supported). The
1854following is the syntax for constant expressions:</p>
1855
1856<dl>
1857 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1858 <dd>Truncate a constant to another type. The bit size of CST must be larger
1859 than the bit size of TYPE. Both types must be integers.</dd>
1860
1861 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1862 <dd>Zero extend a constant to another type. The bit size of CST must be
1863 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1864
1865 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1866 <dd>Sign extend a constant to another type. The bit size of CST must be
1867 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1868
1869 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1870 <dd>Truncate a floating point constant to another floating point type. The
1871 size of CST must be larger than the size of TYPE. Both types must be
1872 floating point.</dd>
1873
1874 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1875 <dd>Floating point extend a constant to another type. The size of CST must be
1876 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1877
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]1878 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1879 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1880 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1881 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1882 of the same number of elements. If the value won't fit in the integer type,
1883 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1884
1885 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
1886 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1887 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1888 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1889 of the same number of elements. If the value won't fit in the integer type,
1890 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1891
1892 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
1893 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1894 constant. TYPE must be a scalar or vector floating point type. CST must be of
1895 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1896 of the same number of elements. If the value won't fit in the floating point
1897 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1898
1899 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
1900 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1901 constant. TYPE must be a scalar or vector floating point type. CST must be of
1902 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1903 of the same number of elements. If the value won't fit in the floating point
1904 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1905
1906 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1907 <dd>Convert a pointer typed constant to the corresponding integer constant
1908 TYPE must be an integer type. CST must be of pointer type. The CST value is
1909 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1910
1911 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1912 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1913 pointer type. CST must be of integer type. The CST value is zero extended,
1914 truncated, or unchanged to make it fit in a pointer size. This one is
1915 <i>really</i> dangerous!</dd>
1916
1917 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
1918 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1919 identical (same number of bits). The conversion is done as if the CST value
1920 was stored to memory and read back as TYPE. In other words, no bits change
1921 with this operator, just the type. This can be used for conversion of
1922 vector types to any other type, as long as they have the same bit width. For
Dan Gohman7305fa02008-09-08 16:45:59 +0000[diff] [blame]1923 pointers it is only valid to cast to another pointer type. It is not valid
1924 to bitcast to or from an aggregate type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1925 </dd>
1926
1927 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1928
1929 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1930 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1931 instruction, the index list may have zero or more indexes, which are required
1932 to make sense for the type of "CSTPTR".</dd>
1933
1934 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1935
1936 <dd>Perform the <a href="#i_select">select operation</a> on
1937 constants.</dd>
1938
1939 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1940 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1941
1942 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1943 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
1944
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]1945 <dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
1946 <dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
1947
1948 <dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
1949 <dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
1950
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1951 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1952
1953 <dd>Perform the <a href="#i_extractelement">extractelement
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1954 operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1955
1956 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1957
1958 <dd>Perform the <a href="#i_insertelement">insertelement
1959 operation</a> on constants.</dd>
1960
1961
1962 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1963
1964 <dd>Perform the <a href="#i_shufflevector">shufflevector
1965 operation</a> on constants.</dd>
1966
1967 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1968
1969 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1970 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
1971 binary</a> operations. The constraints on operands are the same as those for
1972 the corresponding instruction (e.g. no bitwise operations on floating point
1973 values are allowed).</dd>
1974</dl>
1975</div>
1976
1977<!-- *********************************************************************** -->
1978<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1979<!-- *********************************************************************** -->
1980
1981<!-- ======================================================================= -->
1982<div class="doc_subsection">
1983<a name="inlineasm">Inline Assembler Expressions</a>
1984</div>
1985
1986<div class="doc_text">
1987
1988<p>
1989LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1990Module-Level Inline Assembly</a>) through the use of a special value. This
1991value represents the inline assembler as a string (containing the instructions
1992to emit), a list of operand constraints (stored as a string), and a flag that
1993indicates whether or not the inline asm expression has side effects. An example
1994inline assembler expression is:
1995</p>
1996
1997<div class="doc_code">
1998<pre>
1999i32 (i32) asm "bswap $0", "=r,r"
2000</pre>
2001</div>
2002
2003<p>
2004Inline assembler expressions may <b>only</b> be used as the callee operand of
2005a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
2006</p>
2007
2008<div class="doc_code">
2009<pre>
2010%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2011</pre>
2012</div>
2013
2014<p>
2015Inline asms with side effects not visible in the constraint list must be marked
2016as having side effects. This is done through the use of the
2017'<tt>sideeffect</tt>' keyword, like so:
2018</p>
2019
2020<div class="doc_code">
2021<pre>
2022call void asm sideeffect "eieio", ""()
2023</pre>
2024</div>
2025
2026<p>TODO: The format of the asm and constraints string still need to be
2027documented here. Constraints on what can be done (e.g. duplication, moving, etc
Chris Lattner1cdd64e2008-10-04 18:36:02 +0000[diff] [blame]2028need to be documented). This is probably best done by reference to another
2029document that covers inline asm from a holistic perspective.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2030</p>
2031
2032</div>
2033
2034<!-- *********************************************************************** -->
2035<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2036<!-- *********************************************************************** -->
2037
2038<div class="doc_text">
2039
2040<p>The LLVM instruction set consists of several different
2041classifications of instructions: <a href="#terminators">terminator
2042instructions</a>, <a href="#binaryops">binary instructions</a>,
2043<a href="#bitwiseops">bitwise binary instructions</a>, <a
2044 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
2045instructions</a>.</p>
2046
2047</div>
2048
2049<!-- ======================================================================= -->
2050<div class="doc_subsection"> <a name="terminators">Terminator
2051Instructions</a> </div>
2052
2053<div class="doc_text">
2054
2055<p>As mentioned <a href="#functionstructure">previously</a>, every
2056basic block in a program ends with a "Terminator" instruction, which
2057indicates which block should be executed after the current block is
2058finished. These terminator instructions typically yield a '<tt>void</tt>'
2059value: they produce control flow, not values (the one exception being
2060the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2061<p>There are six different terminator instructions: the '<a
2062 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
2063instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
2064the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
2065 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
2066 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
2067
2068</div>
2069
2070<!-- _______________________________________________________________________ -->
2071<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2072Instruction</a> </div>
2073<div class="doc_text">
2074<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2075<pre>
2076 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]2077 ret void <i>; Return from void function</i>
2078</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2079
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2080<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2081
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2082<p>The '<tt>ret</tt>' instruction is used to return control flow (and
2083optionally a value) from a function back to the caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2084<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2085returns a value and then causes control flow, and one that just causes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2086control flow to occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2087
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2088<h5>Arguments:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2089
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2090<p>The '<tt>ret</tt>' instruction optionally accepts a single argument,
2091the return value. The type of the return value must be a
2092'<a href="#t_firstclass">first class</a>' type.</p>
2093
2094<p>A function is not <a href="#wellformed">well formed</a> if
2095it it has a non-void return type and contains a '<tt>ret</tt>'
2096instruction with no return value or a return value with a type that
2097does not match its type, or if it has a void return type and contains
2098a '<tt>ret</tt>' instruction with a return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2099
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2100<h5>Semantics:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2101
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2102<p>When the '<tt>ret</tt>' instruction is executed, control flow
2103returns back to the calling function's context. If the caller is a "<a
2104 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
2105the instruction after the call. If the caller was an "<a
2106 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
2107at the beginning of the "normal" destination block. If the instruction
2108returns a value, that value shall set the call or invoke instruction's
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2109return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2110
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2111<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2112
2113<pre>
2114 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2115 ret void <i>; Return from a void function</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2116 ret { i32, i8 } { i32 4, i8 2 } <i>; Return an aggregate of values 4 and 2</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2117</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2118
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]2119<p>Note that the code generator does not yet fully support large
2120 return values. The specific sizes that are currently supported are
2121 dependent on the target. For integers, on 32-bit targets the limit
2122 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2123 For aggregate types, the current limits are dependent on the element
2124 types; for example targets are often limited to 2 total integer
2125 elements and 2 total floating-point elements.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2126
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2127</div>
2128<!-- _______________________________________________________________________ -->
2129<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
2130<div class="doc_text">
2131<h5>Syntax:</h5>
2132<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
2133</pre>
2134<h5>Overview:</h5>
2135<p>The '<tt>br</tt>' instruction is used to cause control flow to
2136transfer to a different basic block in the current function. There are
2137two forms of this instruction, corresponding to a conditional branch
2138and an unconditional branch.</p>
2139<h5>Arguments:</h5>
2140<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
2141single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
2142unconditional form of the '<tt>br</tt>' instruction takes a single
2143'<tt>label</tt>' value as a target.</p>
2144<h5>Semantics:</h5>
2145<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
2146argument is evaluated. If the value is <tt>true</tt>, control flows
2147to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2148control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2149<h5>Example:</h5>
2150<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
2151 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
2152</div>
2153<!-- _______________________________________________________________________ -->
2154<div class="doc_subsubsection">
2155 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2156</div>
2157
2158<div class="doc_text">
2159<h5>Syntax:</h5>
2160
2161<pre>
2162 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2163</pre>
2164
2165<h5>Overview:</h5>
2166
2167<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
2168several different places. It is a generalization of the '<tt>br</tt>'
2169instruction, allowing a branch to occur to one of many possible
2170destinations.</p>
2171
2172
2173<h5>Arguments:</h5>
2174
2175<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
2176comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
2177an array of pairs of comparison value constants and '<tt>label</tt>'s. The
2178table is not allowed to contain duplicate constant entries.</p>
2179
2180<h5>Semantics:</h5>
2181
2182<p>The <tt>switch</tt> instruction specifies a table of values and
2183destinations. When the '<tt>switch</tt>' instruction is executed, this
2184table is searched for the given value. If the value is found, control flow is
2185transfered to the corresponding destination; otherwise, control flow is
2186transfered to the default destination.</p>
2187
2188<h5>Implementation:</h5>
2189
2190<p>Depending on properties of the target machine and the particular
2191<tt>switch</tt> instruction, this instruction may be code generated in different
2192ways. For example, it could be generated as a series of chained conditional
2193branches or with a lookup table.</p>
2194
2195<h5>Example:</h5>
2196
2197<pre>
2198 <i>; Emulate a conditional br instruction</i>
2199 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2200 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2201
2202 <i>; Emulate an unconditional br instruction</i>
2203 switch i32 0, label %dest [ ]
2204
2205 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2206 switch i32 %val, label %otherwise [ i32 0, label %onzero
2207 i32 1, label %onone
2208 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2209</pre>
2210</div>
2211
2212<!-- _______________________________________________________________________ -->
2213<div class="doc_subsubsection">
2214 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2215</div>
2216
2217<div class="doc_text">
2218
2219<h5>Syntax:</h5>
2220
2221<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2222 &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]2223 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2224</pre>
2225
2226<h5>Overview:</h5>
2227
2228<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
2229function, with the possibility of control flow transfer to either the
2230'<tt>normal</tt>' label or the
2231'<tt>exception</tt>' label. If the callee function returns with the
2232"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
2233"normal" label. If the callee (or any indirect callees) returns with the "<a
2234href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2235continued at the dynamically nearest "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2236
2237<h5>Arguments:</h5>
2238
2239<p>This instruction requires several arguments:</p>
2240
2241<ol>
2242 <li>
2243 The optional "cconv" marker indicates which <a href="#callingconv">calling
2244 convention</a> the call should use. If none is specified, the call defaults
2245 to using C calling conventions.
2246 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2247
2248 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
2249 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
2250 and '<tt>inreg</tt>' attributes are valid here.</li>
2251
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2252 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
2253 function value being invoked. In most cases, this is a direct function
2254 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
2255 an arbitrary pointer to function value.
2256 </li>
2257
2258 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
2259 function to be invoked. </li>
2260
2261 <li>'<tt>function args</tt>': argument list whose types match the function
2262 signature argument types. If the function signature indicates the function
2263 accepts a variable number of arguments, the extra arguments can be
2264 specified. </li>
2265
2266 <li>'<tt>normal label</tt>': the label reached when the called function
2267 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2268
2269 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2270 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2271
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2272 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2273 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2274 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2275</ol>
2276
2277<h5>Semantics:</h5>
2278
2279<p>This instruction is designed to operate as a standard '<tt><a
2280href="#i_call">call</a></tt>' instruction in most regards. The primary
2281difference is that it establishes an association with a label, which is used by
2282the runtime library to unwind the stack.</p>
2283
2284<p>This instruction is used in languages with destructors to ensure that proper
2285cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2286exception. Additionally, this is important for implementation of
2287'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2288
2289<h5>Example:</h5>
2290<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2291 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2292 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2293 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2294 unwind label %TestCleanup <i>; {i32}:retval set</i>
2295</pre>
2296</div>
2297
2298
2299<!-- _______________________________________________________________________ -->
2300
2301<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2302Instruction</a> </div>
2303
2304<div class="doc_text">
2305
2306<h5>Syntax:</h5>
2307<pre>
2308 unwind
2309</pre>
2310
2311<h5>Overview:</h5>
2312
2313<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2314at the first callee in the dynamic call stack which used an <a
2315href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2316primarily used to implement exception handling.</p>
2317
2318<h5>Semantics:</h5>
2319
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2320<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2321immediately halt. The dynamic call stack is then searched for the first <a
2322href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2323execution continues at the "exceptional" destination block specified by the
2324<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2325dynamic call chain, undefined behavior results.</p>
2326</div>
2327
2328<!-- _______________________________________________________________________ -->
2329
2330<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2331Instruction</a> </div>
2332
2333<div class="doc_text">
2334
2335<h5>Syntax:</h5>
2336<pre>
2337 unreachable
2338</pre>
2339
2340<h5>Overview:</h5>
2341
2342<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2343instruction is used to inform the optimizer that a particular portion of the
2344code is not reachable. This can be used to indicate that the code after a
2345no-return function cannot be reached, and other facts.</p>
2346
2347<h5>Semantics:</h5>
2348
2349<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2350</div>
2351
2352
2353
2354<!-- ======================================================================= -->
2355<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
2356<div class="doc_text">
2357<p>Binary operators are used to do most of the computation in a
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2358program. They require two operands of the same type, execute an operation on them, and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2359produce a single value. The operands might represent
2360multiple 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]2361The result value has the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2362<p>There are several different binary operators:</p>
2363</div>
2364<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2365<div class="doc_subsubsection">
2366 <a name="i_add">'<tt>add</tt>' Instruction</a>
2367</div>
2368
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2369<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2370
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2371<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2372
2373<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2374 &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]2375</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2376
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2377<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2378
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2379<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2380
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2381<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2382
2383<p>The two arguments to the '<tt>add</tt>' instruction must be <a
2384 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
2385 <a href="#t_vector">vector</a> values. Both arguments must have identical
2386 types.</p>
2387
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2388<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2389
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2390<p>The value produced is the integer or floating point sum of the two
2391operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2392
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2393<p>If an integer sum has unsigned overflow, the result returned is the
2394mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2395the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2396
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2397<p>Because LLVM integers use a two's complement representation, this
2398instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2399
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2400<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2401
2402<pre>
2403 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2404</pre>
2405</div>
2406<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2407<div class="doc_subsubsection">
2408 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2409</div>
2410
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2411<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2412
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2413<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2414
2415<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2416 &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]2417</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2418
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2419<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2420
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2421<p>The '<tt>sub</tt>' instruction returns the difference of its two
2422operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2423
2424<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2425'<tt>neg</tt>' instruction present in most other intermediate
2426representations.</p>
2427
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2428<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2429
2430<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
2431 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2432 or <a href="#t_vector">vector</a> values. Both arguments must have identical
2433 types.</p>
2434
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2435<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2436
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2437<p>The value produced is the integer or floating point difference of
2438the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2439
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2440<p>If an integer difference has unsigned overflow, the result returned is the
2441mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2442the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2443
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2444<p>Because LLVM integers use a two's complement representation, this
2445instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2446
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2447<h5>Example:</h5>
2448<pre>
2449 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2450 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2451</pre>
2452</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2453
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2454<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2455<div class="doc_subsubsection">
2456 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2457</div>
2458
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2459<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2460
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2461<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2462<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]2463</pre>
2464<h5>Overview:</h5>
2465<p>The '<tt>mul</tt>' instruction returns the product of its two
2466operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2467
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2468<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2469
2470<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
2471href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2472or <a href="#t_vector">vector</a> values. Both arguments must have identical
2473types.</p>
2474
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2475<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2476
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2477<p>The value produced is the integer or floating point product of the
2478two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2479
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2480<p>If the result of an integer multiplication has unsigned overflow,
2481the result returned is the mathematical result modulo
24822<sup>n</sup>, where n is the bit width of the result.</p>
2483<p>Because LLVM integers use a two's complement representation, and the
2484result is the same width as the operands, this instruction returns the
2485correct result for both signed and unsigned integers. If a full product
2486(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2487should be sign-extended or zero-extended as appropriate to the
2488width of the full product.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2489<h5>Example:</h5>
2490<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
2491</pre>
2492</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2493
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2494<!-- _______________________________________________________________________ -->
2495<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2496</a></div>
2497<div class="doc_text">
2498<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2499<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]2500</pre>
2501<h5>Overview:</h5>
2502<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2503operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2504
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2505<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2506
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2507<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2508<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2509values. Both arguments must have identical types.</p>
2510
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2511<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2512
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2513<p>The value produced is the unsigned integer quotient of the two operands.</p>
2514<p>Note that unsigned integer division and signed integer division are distinct
2515operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2516<p>Division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2517<h5>Example:</h5>
2518<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2519</pre>
2520</div>
2521<!-- _______________________________________________________________________ -->
2522<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2523</a> </div>
2524<div class="doc_text">
2525<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2526<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2527 &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]2528</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2529
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2530<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2531
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2532<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2533operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2534
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2535<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2536
2537<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2538<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2539values. Both arguments must have identical types.</p>
2540
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2541<h5>Semantics:</h5>
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2542<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]2543<p>Note that signed integer division and unsigned integer division are distinct
2544operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2545<p>Division by zero leads to undefined behavior. Overflow also leads to
2546undefined behavior; this is a rare case, but can occur, for example,
2547by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2548<h5>Example:</h5>
2549<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2550</pre>
2551</div>
2552<!-- _______________________________________________________________________ -->
2553<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2554Instruction</a> </div>
2555<div class="doc_text">
2556<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2557<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2558 &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]2559</pre>
2560<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2561
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2562<p>The '<tt>fdiv</tt>' instruction returns the quotient 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
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2567<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2568<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2569of floating point values. Both arguments must have identical types.</p>
2570
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2571<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2572
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2573<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2574
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2575<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2576
2577<pre>
2578 &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]2579</pre>
2580</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2581
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2582<!-- _______________________________________________________________________ -->
2583<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2584</div>
2585<div class="doc_text">
2586<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2587<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]2588</pre>
2589<h5>Overview:</h5>
2590<p>The '<tt>urem</tt>' instruction returns the remainder from the
2591unsigned division of its two arguments.</p>
2592<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2593<p>The two arguments to the '<tt>urem</tt>' instruction must be
2594<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2595values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2596<h5>Semantics:</h5>
2597<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2598This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2599<p>Note that unsigned integer remainder and signed integer remainder are
2600distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2601<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2602<h5>Example:</h5>
2603<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2604</pre>
2605
2606</div>
2607<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2608<div class="doc_subsubsection">
2609 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2610</div>
2611
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2612<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2613
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2614<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2615
2616<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2617 &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]2618</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2619
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2620<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2621
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2622<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman3e3fd8c2007-11-05 23:35:22 +0000[diff] [blame]2623signed division of its two operands. This instruction can also take
2624<a href="#t_vector">vector</a> versions of the values in which case
2625the elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]2626
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2627<h5>Arguments:</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 two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2630<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2631values. Both arguments must have identical types.</p>
2632
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2633<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2634
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2635<p>This instruction returns the <i>remainder</i> of a division (where the result
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2636has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
2637operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2638a value. For more information about the difference, see <a
2639 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2640Math Forum</a>. For a table of how this is implemented in various languages,
2641please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
2642Wikipedia: modulo operation</a>.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2643<p>Note that signed integer remainder and unsigned integer remainder are
2644distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2645<p>Taking the remainder of a division by zero leads to undefined behavior.
2646Overflow also leads to undefined behavior; this is a rare case, but can occur,
2647for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2648(The remainder doesn't actually overflow, but this rule lets srem be
2649implemented using instructions that return both the result of the division
2650and the remainder.)</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2651<h5>Example:</h5>
2652<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2653</pre>
2654
2655</div>
2656<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2657<div class="doc_subsubsection">
2658 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2659
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2660<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2661
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2662<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2663<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]2664</pre>
2665<h5>Overview:</h5>
2666<p>The '<tt>frem</tt>' instruction returns the remainder from the
2667division of its two operands.</p>
2668<h5>Arguments:</h5>
2669<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2670<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2671of floating point values. Both arguments must have identical types.</p>
2672
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2673<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2674
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2675<p>This instruction returns the <i>remainder</i> of a division.
2676The remainder has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2677
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2678<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2679
2680<pre>
2681 &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]2682</pre>
2683</div>
2684
2685<!-- ======================================================================= -->
2686<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2687Operations</a> </div>
2688<div class="doc_text">
2689<p>Bitwise binary operators are used to do various forms of
2690bit-twiddling in a program. They are generally very efficient
2691instructions and can commonly be strength reduced from other
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2692instructions. They require two operands of the same type, execute an operation on them,
2693and 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]2694</div>
2695
2696<!-- _______________________________________________________________________ -->
2697<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2698Instruction</a> </div>
2699<div class="doc_text">
2700<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2701<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]2702</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2703
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2704<h5>Overview:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2705
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2706<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2707the left a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2708
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2709<h5>Arguments:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2710
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2711<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2712 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2713type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2714
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2715<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2716
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2717<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
2718where 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]2719equal to or larger than the number of bits in <tt>op1</tt>, the result is undefined.
2720If the arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2721corresponding shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2722
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2723<h5>Example:</h5><pre>
2724 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2725 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2726 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2727 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2728 &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]2729</pre>
2730</div>
2731<!-- _______________________________________________________________________ -->
2732<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2733Instruction</a> </div>
2734<div class="doc_text">
2735<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2736<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]2737</pre>
2738
2739<h5>Overview:</h5>
2740<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2741operand shifted to the right a specified number of bits with zero fill.</p>
2742
2743<h5>Arguments:</h5>
2744<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2745<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]2746type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2747
2748<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2749
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2750<p>This instruction always performs a logical shift right operation. The most
2751significant bits of the result will be filled with zero bits after the
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2752shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2753the number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
2754vectors, each vector element of <tt>op1</tt> is shifted by the corresponding shift
2755amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2756
2757<h5>Example:</h5>
2758<pre>
2759 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2760 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2761 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2762 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2763 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2764 &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]2765</pre>
2766</div>
2767
2768<!-- _______________________________________________________________________ -->
2769<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2770Instruction</a> </div>
2771<div class="doc_text">
2772
2773<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2774<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]2775</pre>
2776
2777<h5>Overview:</h5>
2778<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2779operand shifted to the right a specified number of bits with sign extension.</p>
2780
2781<h5>Arguments:</h5>
2782<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2783<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]2784type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2785
2786<h5>Semantics:</h5>
2787<p>This instruction always performs an arithmetic shift right operation,
2788The most significant bits of the result will be filled with the sign bit
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2789of <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]2790larger than the number of bits in <tt>op1</tt>, the result is undefined. If the
2791arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2792corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2793
2794<h5>Example:</h5>
2795<pre>
2796 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2797 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2798 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2799 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2800 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2801 &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]2802</pre>
2803</div>
2804
2805<!-- _______________________________________________________________________ -->
2806<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2807Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2808
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2809<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2810
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2811<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2812
2813<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2814 &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]2815</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2816
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2817<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2818
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2819<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2820its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2821
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2822<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2823
2824<p>The two arguments to the '<tt>and</tt>' instruction must be
2825<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2826values. Both arguments must have identical types.</p>
2827
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2828<h5>Semantics:</h5>
2829<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
2830<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2831<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2832<table border="1" cellspacing="0" cellpadding="4">
2833 <tbody>
2834 <tr>
2835 <td>In0</td>
2836 <td>In1</td>
2837 <td>Out</td>
2838 </tr>
2839 <tr>
2840 <td>0</td>
2841 <td>0</td>
2842 <td>0</td>
2843 </tr>
2844 <tr>
2845 <td>0</td>
2846 <td>1</td>
2847 <td>0</td>
2848 </tr>
2849 <tr>
2850 <td>1</td>
2851 <td>0</td>
2852 <td>0</td>
2853 </tr>
2854 <tr>
2855 <td>1</td>
2856 <td>1</td>
2857 <td>1</td>
2858 </tr>
2859 </tbody>
2860</table>
2861</div>
2862<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2863<pre>
2864 &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]2865 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2866 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
2867</pre>
2868</div>
2869<!-- _______________________________________________________________________ -->
2870<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
2871<div class="doc_text">
2872<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2873<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]2874</pre>
2875<h5>Overview:</h5>
2876<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2877or of its two operands.</p>
2878<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2879
2880<p>The two arguments to the '<tt>or</tt>' instruction must be
2881<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2882values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2883<h5>Semantics:</h5>
2884<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
2885<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2886<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2887<table border="1" cellspacing="0" cellpadding="4">
2888 <tbody>
2889 <tr>
2890 <td>In0</td>
2891 <td>In1</td>
2892 <td>Out</td>
2893 </tr>
2894 <tr>
2895 <td>0</td>
2896 <td>0</td>
2897 <td>0</td>
2898 </tr>
2899 <tr>
2900 <td>0</td>
2901 <td>1</td>
2902 <td>1</td>
2903 </tr>
2904 <tr>
2905 <td>1</td>
2906 <td>0</td>
2907 <td>1</td>
2908 </tr>
2909 <tr>
2910 <td>1</td>
2911 <td>1</td>
2912 <td>1</td>
2913 </tr>
2914 </tbody>
2915</table>
2916</div>
2917<h5>Example:</h5>
2918<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2919 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2920 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
2921</pre>
2922</div>
2923<!-- _______________________________________________________________________ -->
2924<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2925Instruction</a> </div>
2926<div class="doc_text">
2927<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2928<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]2929</pre>
2930<h5>Overview:</h5>
2931<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2932or of its two operands. The <tt>xor</tt> is used to implement the
2933"one's complement" operation, which is the "~" operator in C.</p>
2934<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2935<p>The two arguments to the '<tt>xor</tt>' instruction must be
2936<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2937values. Both arguments must have identical types.</p>
2938
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2939<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2940
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2941<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
2942<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2943<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2944<table border="1" cellspacing="0" cellpadding="4">
2945 <tbody>
2946 <tr>
2947 <td>In0</td>
2948 <td>In1</td>
2949 <td>Out</td>
2950 </tr>
2951 <tr>
2952 <td>0</td>
2953 <td>0</td>
2954 <td>0</td>
2955 </tr>
2956 <tr>
2957 <td>0</td>
2958 <td>1</td>
2959 <td>1</td>
2960 </tr>
2961 <tr>
2962 <td>1</td>
2963 <td>0</td>
2964 <td>1</td>
2965 </tr>
2966 <tr>
2967 <td>1</td>
2968 <td>1</td>
2969 <td>0</td>
2970 </tr>
2971 </tbody>
2972</table>
2973</div>
2974<p> </p>
2975<h5>Example:</h5>
2976<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2977 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2978 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2979 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
2980</pre>
2981</div>
2982
2983<!-- ======================================================================= -->
2984<div class="doc_subsection">
2985 <a name="vectorops">Vector Operations</a>
2986</div>
2987
2988<div class="doc_text">
2989
2990<p>LLVM supports several instructions to represent vector operations in a
2991target-independent manner. These instructions cover the element-access and
2992vector-specific operations needed to process vectors effectively. While LLVM
2993does directly support these vector operations, many sophisticated algorithms
2994will want to use target-specific intrinsics to take full advantage of a specific
2995target.</p>
2996
2997</div>
2998
2999<!-- _______________________________________________________________________ -->
3000<div class="doc_subsubsection">
3001 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3002</div>
3003
3004<div class="doc_text">
3005
3006<h5>Syntax:</h5>
3007
3008<pre>
3009 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3010</pre>
3011
3012<h5>Overview:</h5>
3013
3014<p>
3015The '<tt>extractelement</tt>' instruction extracts a single scalar
3016element from a vector at a specified index.
3017</p>
3018
3019
3020<h5>Arguments:</h5>
3021
3022<p>
3023The first operand of an '<tt>extractelement</tt>' instruction is a
3024value of <a href="#t_vector">vector</a> type. The second operand is
3025an index indicating the position from which to extract the element.
3026The index may be a variable.</p>
3027
3028<h5>Semantics:</h5>
3029
3030<p>
3031The result is a scalar of the same type as the element type of
3032<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3033<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3034results are undefined.
3035</p>
3036
3037<h5>Example:</h5>
3038
3039<pre>
3040 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
3041</pre>
3042</div>
3043
3044
3045<!-- _______________________________________________________________________ -->
3046<div class="doc_subsubsection">
3047 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3048</div>
3049
3050<div class="doc_text">
3051
3052<h5>Syntax:</h5>
3053
3054<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3055 &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]3056</pre>
3057
3058<h5>Overview:</h5>
3059
3060<p>
3061The '<tt>insertelement</tt>' instruction inserts a scalar
3062element into a vector at a specified index.
3063</p>
3064
3065
3066<h5>Arguments:</h5>
3067
3068<p>
3069The first operand of an '<tt>insertelement</tt>' instruction is a
3070value of <a href="#t_vector">vector</a> type. The second operand is a
3071scalar value whose type must equal the element type of the first
3072operand. The third operand is an index indicating the position at
3073which to insert the value. The index may be a variable.</p>
3074
3075<h5>Semantics:</h5>
3076
3077<p>
3078The result is a vector of the same type as <tt>val</tt>. Its
3079element values are those of <tt>val</tt> except at position
3080<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
3081exceeds the length of <tt>val</tt>, the results are undefined.
3082</p>
3083
3084<h5>Example:</h5>
3085
3086<pre>
3087 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
3088</pre>
3089</div>
3090
3091<!-- _______________________________________________________________________ -->
3092<div class="doc_subsubsection">
3093 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3094</div>
3095
3096<div class="doc_text">
3097
3098<h5>Syntax:</h5>
3099
3100<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3101 &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]3102</pre>
3103
3104<h5>Overview:</h5>
3105
3106<p>
3107The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3108from two input vectors, returning a vector with the same element type as
3109the input and length that is the same as the shuffle mask.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3110</p>
3111
3112<h5>Arguments:</h5>
3113
3114<p>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3115The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3116with types that match each other. The third argument is a shuffle mask whose
3117element type is always 'i32'. The result of the instruction is a vector whose
3118length is the same as the shuffle mask and whose element type is the same as
3119the element type of the first two operands.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3120</p>
3121
3122<p>
3123The shuffle mask operand is required to be a constant vector with either
3124constant integer or undef values.
3125</p>
3126
3127<h5>Semantics:</h5>
3128
3129<p>
3130The elements of the two input vectors are numbered from left to right across
3131both of the vectors. The shuffle mask operand specifies, for each element of
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3132the result vector, which element of the two input vectors the result element
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3133gets. The element selector may be undef (meaning "don't care") and the second
3134operand may be undef if performing a shuffle from only one vector.
3135</p>
3136
3137<h5>Example:</h5>
3138
3139<pre>
3140 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3141 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3142 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3143 &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]3144 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3145 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3146 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3147 &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]3148</pre>
3149</div>
3150
3151
3152<!-- ======================================================================= -->
3153<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3154 <a name="aggregateops">Aggregate Operations</a>
3155</div>
3156
3157<div class="doc_text">
3158
3159<p>LLVM supports several instructions for working with aggregate values.
3160</p>
3161
3162</div>
3163
3164<!-- _______________________________________________________________________ -->
3165<div class="doc_subsubsection">
3166 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3167</div>
3168
3169<div class="doc_text">
3170
3171<h5>Syntax:</h5>
3172
3173<pre>
3174 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3175</pre>
3176
3177<h5>Overview:</h5>
3178
3179<p>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3180The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3181or array element from an aggregate value.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3182</p>
3183
3184
3185<h5>Arguments:</h5>
3186
3187<p>
3188The first operand of an '<tt>extractvalue</tt>' instruction is a
3189value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3190type. The operands are constant indices to specify which value to extract
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3191in a similar manner as indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3192'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3193</p>
3194
3195<h5>Semantics:</h5>
3196
3197<p>
3198The result is the value at the position in the aggregate specified by
3199the index operands.
3200</p>
3201
3202<h5>Example:</h5>
3203
3204<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3205 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3206</pre>
3207</div>
3208
3209
3210<!-- _______________________________________________________________________ -->
3211<div class="doc_subsubsection">
3212 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3213</div>
3214
3215<div class="doc_text">
3216
3217<h5>Syntax:</h5>
3218
3219<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3220 &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]3221</pre>
3222
3223<h5>Overview:</h5>
3224
3225<p>
3226The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3227into a struct field or array element in an aggregate.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3228</p>
3229
3230
3231<h5>Arguments:</h5>
3232
3233<p>
3234The first operand of an '<tt>insertvalue</tt>' instruction is a
3235value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
3236The second operand is a first-class value to insert.
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]3237The following operands are constant indices
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3238indicating the position at which to insert the value in a similar manner as
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3239indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3240'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3241The value to insert must have the same type as the value identified
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3242by the indices.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3243</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3244
3245<h5>Semantics:</h5>
3246
3247<p>
3248The result is an aggregate of the same type as <tt>val</tt>. Its
3249value is that of <tt>val</tt> except that the value at the position
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3250specified by the indices is that of <tt>elt</tt>.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3251</p>
3252
3253<h5>Example:</h5>
3254
3255<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3256 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3257</pre>
3258</div>
3259
3260
3261<!-- ======================================================================= -->
3262<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3263 <a name="memoryops">Memory Access and Addressing Operations</a>
3264</div>
3265
3266<div class="doc_text">
3267
3268<p>A key design point of an SSA-based representation is how it
3269represents memory. In LLVM, no memory locations are in SSA form, which
3270makes things very simple. This section describes how to read, write,
3271allocate, and free memory in LLVM.</p>
3272
3273</div>
3274
3275<!-- _______________________________________________________________________ -->
3276<div class="doc_subsubsection">
3277 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3278</div>
3279
3280<div class="doc_text">
3281
3282<h5>Syntax:</h5>
3283
3284<pre>
3285 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3286</pre>
3287
3288<h5>Overview:</h5>
3289
3290<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3291heap and returns a pointer to it. The object is always allocated in the generic
3292address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3293
3294<h5>Arguments:</h5>
3295
3296<p>The '<tt>malloc</tt>' instruction allocates
3297<tt>sizeof(&lt;type&gt;)*NumElements</tt>
3298bytes of memory from the operating system and returns a pointer of the
3299appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3300number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3301If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3302be aligned to at least that boundary. If not specified, or if zero, the target can
3303choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3304
3305<p>'<tt>type</tt>' must be a sized type.</p>
3306
3307<h5>Semantics:</h5>
3308
3309<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]3310a pointer is returned. The result of a zero byte allocation is undefined. The
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3311result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3312
3313<h5>Example:</h5>
3314
3315<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3316 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3317
3318 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3319 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3320 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3321 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3322 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3323</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3324
3325<p>Note that the code generator does not yet respect the
3326 alignment value.</p>
3327
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3328</div>
3329
3330<!-- _______________________________________________________________________ -->
3331<div class="doc_subsubsection">
3332 <a name="i_free">'<tt>free</tt>' Instruction</a>
3333</div>
3334
3335<div class="doc_text">
3336
3337<h5>Syntax:</h5>
3338
3339<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3340 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3341</pre>
3342
3343<h5>Overview:</h5>
3344
3345<p>The '<tt>free</tt>' instruction returns memory back to the unused
3346memory heap to be reallocated in the future.</p>
3347
3348<h5>Arguments:</h5>
3349
3350<p>'<tt>value</tt>' shall be a pointer value that points to a value
3351that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3352instruction.</p>
3353
3354<h5>Semantics:</h5>
3355
3356<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner329d6532008-04-19 22:41:32 +0000[diff] [blame]3357after this instruction executes. If the pointer is null, the operation
3358is a noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3359
3360<h5>Example:</h5>
3361
3362<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3363 %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]3364 free [4 x i8]* %array
3365</pre>
3366</div>
3367
3368<!-- _______________________________________________________________________ -->
3369<div class="doc_subsubsection">
3370 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3371</div>
3372
3373<div class="doc_text">
3374
3375<h5>Syntax:</h5>
3376
3377<pre>
3378 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3379</pre>
3380
3381<h5>Overview:</h5>
3382
3383<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3384currently executing function, to be automatically released when this function
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3385returns to its caller. The object is always allocated in the generic address
3386space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3387
3388<h5>Arguments:</h5>
3389
3390<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
3391bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3392appropriate type to the program. If "NumElements" is specified, it is the
3393number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3394If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3395to be aligned to at least that boundary. If not specified, or if zero, the target
3396can choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3397
3398<p>'<tt>type</tt>' may be any sized type.</p>
3399
3400<h5>Semantics:</h5>
3401
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3402<p>Memory is allocated; a pointer is returned. The operation is undefiend if
3403there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3404memory is automatically released when the function returns. The '<tt>alloca</tt>'
3405instruction is commonly used to represent automatic variables that must
3406have an address available. When the function returns (either with the <tt><a
3407 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]3408instructions), the memory is reclaimed. Allocating zero bytes
3409is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3410
3411<h5>Example:</h5>
3412
3413<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3414 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3415 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3416 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3417 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3418</pre>
3419</div>
3420
3421<!-- _______________________________________________________________________ -->
3422<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3423Instruction</a> </div>
3424<div class="doc_text">
3425<h5>Syntax:</h5>
3426<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>
3427<h5>Overview:</h5>
3428<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
3429<h5>Arguments:</h5>
3430<p>The argument to the '<tt>load</tt>' instruction specifies the memory
3431address from which to load. The pointer must point to a <a
3432 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3433marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
3434the number or order of execution of this <tt>load</tt> with other
3435volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3436instructions. </p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3437<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3438The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3439(that is, the alignment of the memory address). A value of 0 or an
3440omitted "align" argument means that the operation has the preferential
3441alignment for the target. It is the responsibility of the code emitter
3442to ensure that the alignment information is correct. Overestimating
3443the alignment results in an undefined behavior. Underestimating the
3444alignment may produce less efficient code. An alignment of 1 is always
3445safe.
3446</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3447<h5>Semantics:</h5>
3448<p>The location of memory pointed to is loaded.</p>
3449<h5>Examples:</h5>
3450<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3451 <a
3452 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3453 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3454</pre>
3455</div>
3456<!-- _______________________________________________________________________ -->
3457<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3458Instruction</a> </div>
3459<div class="doc_text">
3460<h5>Syntax:</h5>
3461<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3462 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3463</pre>
3464<h5>Overview:</h5>
3465<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
3466<h5>Arguments:</h5>
3467<p>There are two arguments to the '<tt>store</tt>' instruction: a value
3468to 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]3469operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3470of the '<tt>&lt;value&gt;</tt>'
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3471operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
3472optimizer is not allowed to modify the number or order of execution of
3473this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3474 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3475<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3476The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3477(that is, the alignment of the memory address). A value of 0 or an
3478omitted "align" argument means that the operation has the preferential
3479alignment for the target. It is the responsibility of the code emitter
3480to ensure that the alignment information is correct. Overestimating
3481the alignment results in an undefined behavior. Underestimating the
3482alignment may produce less efficient code. An alignment of 1 is always
3483safe.
3484</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3485<h5>Semantics:</h5>
3486<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
3487at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
3488<h5>Example:</h5>
3489<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3490 store i32 3, i32* %ptr <i>; yields {void}</i>
3491 %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]3492</pre>
3493</div>
3494
3495<!-- _______________________________________________________________________ -->
3496<div class="doc_subsubsection">
3497 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3498</div>
3499
3500<div class="doc_text">
3501<h5>Syntax:</h5>
3502<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3503 &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]3504</pre>
3505
3506<h5>Overview:</h5>
3507
3508<p>
3509The '<tt>getelementptr</tt>' instruction is used to get the address of a
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3510subelement of an aggregate data structure. It performs address calculation only
3511and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3512
3513<h5>Arguments:</h5>
3514
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3515<p>The first argument is always a pointer, and forms the basis of the
3516calculation. The remaining arguments are indices, that indicate which of the
3517elements of the aggregate object are indexed. The interpretation of each index
3518is dependent on the type being indexed into. The first index always indexes the
3519pointer value given as the first argument, the second index indexes a value of
3520the type pointed to (not necessarily the value directly pointed to, since the
3521first index can be non-zero), etc. The first type indexed into must be a pointer
3522value, subsequent types can be arrays, vectors and structs. Note that subsequent
3523types being indexed into can never be pointers, since that would require loading
3524the pointer before continuing calculation.</p>
3525
3526<p>The type of each index argument depends on the type it is indexing into.
3527When indexing into a (packed) structure, only <tt>i32</tt> integer
3528<b>constants</b> are allowed. When indexing into an array, pointer or vector,
3529only integers of 32 or 64 bits are allowed (also non-constants). 32-bit values
3530will be sign extended to 64-bits if required.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3531
3532<p>For example, let's consider a C code fragment and how it gets
3533compiled to LLVM:</p>
3534
3535<div class="doc_code">
3536<pre>
3537struct RT {
3538 char A;
3539 int B[10][20];
3540 char C;
3541};
3542struct ST {
3543 int X;
3544 double Y;
3545 struct RT Z;
3546};
3547
3548int *foo(struct ST *s) {
3549 return &amp;s[1].Z.B[5][13];
3550}
3551</pre>
3552</div>
3553
3554<p>The LLVM code generated by the GCC frontend is:</p>
3555
3556<div class="doc_code">
3557<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]3558%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
3559%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3560
3561define i32* %foo(%ST* %s) {
3562entry:
3563 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3564 ret i32* %reg
3565}
3566</pre>
3567</div>
3568
3569<h5>Semantics:</h5>
3570
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3571<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
3572type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3573}</tt>' type, a structure. The second index indexes into the third element of
3574the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3575i8 }</tt>' type, another structure. The third index indexes into the second
3576element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3577array. The two dimensions of the array are subscripted into, yielding an
3578'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3579to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
3580
3581<p>Note that it is perfectly legal to index partially through a
3582structure, returning a pointer to an inner element. Because of this,
3583the LLVM code for the given testcase is equivalent to:</p>
3584
3585<pre>
3586 define i32* %foo(%ST* %s) {
3587 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3588 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3589 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3590 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3591 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3592 ret i32* %t5
3593 }
3594</pre>
3595
3596<p>Note that it is undefined to access an array out of bounds: array and
3597pointer indexes must always be within the defined bounds of the array type.
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]3598The one exception for this rule is zero length arrays. These arrays are
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3599defined to be accessible as variable length arrays, which requires access
3600beyond the zero'th element.</p>
3601
3602<p>The getelementptr instruction is often confusing. For some more insight
3603into how it works, see <a href="GetElementPtr.html">the getelementptr
3604FAQ</a>.</p>
3605
3606<h5>Example:</h5>
3607
3608<pre>
3609 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3610 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3611 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3612 %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]3613 <i>; yields i8*:eptr</i>
3614 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3615</pre>
3616</div>
3617
3618<!-- ======================================================================= -->
3619<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3620</div>
3621<div class="doc_text">
3622<p>The instructions in this category are the conversion instructions (casting)
3623which all take a single operand and a type. They perform various bit conversions
3624on the operand.</p>
3625</div>
3626
3627<!-- _______________________________________________________________________ -->
3628<div class="doc_subsubsection">
3629 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3630</div>
3631<div class="doc_text">
3632
3633<h5>Syntax:</h5>
3634<pre>
3635 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3636</pre>
3637
3638<h5>Overview:</h5>
3639<p>
3640The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3641</p>
3642
3643<h5>Arguments:</h5>
3644<p>
3645The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3646be an <a href="#t_integer">integer</a> type, and a type that specifies the size
3647and type of the result, which must be an <a href="#t_integer">integer</a>
3648type. The bit size of <tt>value</tt> must be larger than the bit size of
3649<tt>ty2</tt>. Equal sized types are not allowed.</p>
3650
3651<h5>Semantics:</h5>
3652<p>
3653The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
3654and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3655larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3656It will always truncate bits.</p>
3657
3658<h5>Example:</h5>
3659<pre>
3660 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3661 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3662 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
3663</pre>
3664</div>
3665
3666<!-- _______________________________________________________________________ -->
3667<div class="doc_subsubsection">
3668 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3669</div>
3670<div class="doc_text">
3671
3672<h5>Syntax:</h5>
3673<pre>
3674 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3675</pre>
3676
3677<h5>Overview:</h5>
3678<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3679<tt>ty2</tt>.</p>
3680
3681
3682<h5>Arguments:</h5>
3683<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
3684<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3685also be of <a href="#t_integer">integer</a> type. The bit size of the
3686<tt>value</tt> must be smaller than the bit size of the destination type,
3687<tt>ty2</tt>.</p>
3688
3689<h5>Semantics:</h5>
3690<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
3691bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
3692
3693<p>When zero extending from i1, the result will always be either 0 or 1.</p>
3694
3695<h5>Example:</h5>
3696<pre>
3697 %X = zext i32 257 to i64 <i>; yields i64:257</i>
3698 %Y = zext i1 true to i32 <i>; yields i32:1</i>
3699</pre>
3700</div>
3701
3702<!-- _______________________________________________________________________ -->
3703<div class="doc_subsubsection">
3704 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3705</div>
3706<div class="doc_text">
3707
3708<h5>Syntax:</h5>
3709<pre>
3710 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3711</pre>
3712
3713<h5>Overview:</h5>
3714<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3715
3716<h5>Arguments:</h5>
3717<p>
3718The '<tt>sext</tt>' instruction takes a value to cast, which must be of
3719<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3720also be of <a href="#t_integer">integer</a> type. The bit size of the
3721<tt>value</tt> must be smaller than the bit size of the destination type,
3722<tt>ty2</tt>.</p>
3723
3724<h5>Semantics:</h5>
3725<p>
3726The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3727bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
3728the type <tt>ty2</tt>.</p>
3729
3730<p>When sign extending from i1, the extension always results in -1 or 0.</p>
3731
3732<h5>Example:</h5>
3733<pre>
3734 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
3735 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
3736</pre>
3737</div>
3738
3739<!-- _______________________________________________________________________ -->
3740<div class="doc_subsubsection">
3741 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3742</div>
3743
3744<div class="doc_text">
3745
3746<h5>Syntax:</h5>
3747
3748<pre>
3749 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3750</pre>
3751
3752<h5>Overview:</h5>
3753<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3754<tt>ty2</tt>.</p>
3755
3756
3757<h5>Arguments:</h5>
3758<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3759 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3760cast it to. The size of <tt>value</tt> must be larger than the size of
3761<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3762<i>no-op cast</i>.</p>
3763
3764<h5>Semantics:</h5>
3765<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3766<a href="#t_floating">floating point</a> type to a smaller
3767<a href="#t_floating">floating point</a> type. If the value cannot fit within
3768the destination type, <tt>ty2</tt>, then the results are undefined.</p>
3769
3770<h5>Example:</h5>
3771<pre>
3772 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3773 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3774</pre>
3775</div>
3776
3777<!-- _______________________________________________________________________ -->
3778<div class="doc_subsubsection">
3779 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3780</div>
3781<div class="doc_text">
3782
3783<h5>Syntax:</h5>
3784<pre>
3785 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3786</pre>
3787
3788<h5>Overview:</h5>
3789<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3790floating point value.</p>
3791
3792<h5>Arguments:</h5>
3793<p>The '<tt>fpext</tt>' instruction takes a
3794<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
3795and a <a href="#t_floating">floating point</a> type to cast it to. The source
3796type must be smaller than the destination type.</p>
3797
3798<h5>Semantics:</h5>
3799<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
3800<a href="#t_floating">floating point</a> type to a larger
3801<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
3802used to make a <i>no-op cast</i> because it always changes bits. Use
3803<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
3804
3805<h5>Example:</h5>
3806<pre>
3807 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3808 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3809</pre>
3810</div>
3811
3812<!-- _______________________________________________________________________ -->
3813<div class="doc_subsubsection">
3814 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
3815</div>
3816<div class="doc_text">
3817
3818<h5>Syntax:</h5>
3819<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3820 &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]3821</pre>
3822
3823<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3824<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3825unsigned integer equivalent of type <tt>ty2</tt>.
3826</p>
3827
3828<h5>Arguments:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3829<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]3830scalar or vector <a href="#t_floating">floating point</a> value, and a type
3831to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3832type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3833vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3834
3835<h5>Semantics:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3836<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3837<a href="#t_floating">floating point</a> operand into the nearest (rounding
3838towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3839the results are undefined.</p>
3840
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3841<h5>Example:</h5>
3842<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3843 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3844 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3845 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3846</pre>
3847</div>
3848
3849<!-- _______________________________________________________________________ -->
3850<div class="doc_subsubsection">
3851 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
3852</div>
3853<div class="doc_text">
3854
3855<h5>Syntax:</h5>
3856<pre>
3857 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3858</pre>
3859
3860<h5>Overview:</h5>
3861<p>The '<tt>fptosi</tt>' instruction converts
3862<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
3863</p>
3864
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3865<h5>Arguments:</h5>
3866<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]3867scalar or vector <a href="#t_floating">floating point</a> value, and a type
3868to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3869type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3870vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3871
3872<h5>Semantics:</h5>
3873<p>The '<tt>fptosi</tt>' instruction converts its
3874<a href="#t_floating">floating point</a> operand into the nearest (rounding
3875towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3876the results are undefined.</p>
3877
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3878<h5>Example:</h5>
3879<pre>
3880 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3881 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3882 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
3883</pre>
3884</div>
3885
3886<!-- _______________________________________________________________________ -->
3887<div class="doc_subsubsection">
3888 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
3889</div>
3890<div class="doc_text">
3891
3892<h5>Syntax:</h5>
3893<pre>
3894 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3895</pre>
3896
3897<h5>Overview:</h5>
3898<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
3899integer and converts that value to the <tt>ty2</tt> type.</p>
3900
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3901<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3902<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3903scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3904to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3905type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3906floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3907
3908<h5>Semantics:</h5>
3909<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
3910integer quantity and converts it to the corresponding floating point value. If
3911the value cannot fit in the floating point value, the results are undefined.</p>
3912
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3913<h5>Example:</h5>
3914<pre>
3915 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3916 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3917</pre>
3918</div>
3919
3920<!-- _______________________________________________________________________ -->
3921<div class="doc_subsubsection">
3922 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
3923</div>
3924<div class="doc_text">
3925
3926<h5>Syntax:</h5>
3927<pre>
3928 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3929</pre>
3930
3931<h5>Overview:</h5>
3932<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
3933integer and converts that value to the <tt>ty2</tt> type.</p>
3934
3935<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3936<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3937scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3938to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3939type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3940floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3941
3942<h5>Semantics:</h5>
3943<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
3944integer quantity and converts it to the corresponding floating point value. If
3945the value cannot fit in the floating point value, the results are undefined.</p>
3946
3947<h5>Example:</h5>
3948<pre>
3949 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3950 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3951</pre>
3952</div>
3953
3954<!-- _______________________________________________________________________ -->
3955<div class="doc_subsubsection">
3956 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3957</div>
3958<div class="doc_text">
3959
3960<h5>Syntax:</h5>
3961<pre>
3962 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3963</pre>
3964
3965<h5>Overview:</h5>
3966<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3967the integer type <tt>ty2</tt>.</p>
3968
3969<h5>Arguments:</h5>
3970<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3971must 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]3972<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]3973
3974<h5>Semantics:</h5>
3975<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3976<tt>ty2</tt> by interpreting the pointer value as an integer and either
3977truncating or zero extending that value to the size of the integer type. If
3978<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3979<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3980are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3981change.</p>
3982
3983<h5>Example:</h5>
3984<pre>
3985 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3986 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
3987</pre>
3988</div>
3989
3990<!-- _______________________________________________________________________ -->
3991<div class="doc_subsubsection">
3992 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3993</div>
3994<div class="doc_text">
3995
3996<h5>Syntax:</h5>
3997<pre>
3998 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3999</pre>
4000
4001<h5>Overview:</h5>
4002<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
4003a pointer type, <tt>ty2</tt>.</p>
4004
4005<h5>Arguments:</h5>
4006<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
4007value to cast, and a type to cast it to, which must be a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4008<a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4009
4010<h5>Semantics:</h5>
4011<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
4012<tt>ty2</tt> by applying either a zero extension or a truncation depending on
4013the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4014size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
4015the size of a pointer then a zero extension is done. If they are the same size,
4016nothing is done (<i>no-op cast</i>).</p>
4017
4018<h5>Example:</h5>
4019<pre>
4020 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4021 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4022 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
4023</pre>
4024</div>
4025
4026<!-- _______________________________________________________________________ -->
4027<div class="doc_subsubsection">
4028 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4029</div>
4030<div class="doc_text">
4031
4032<h5>Syntax:</h5>
4033<pre>
4034 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4035</pre>
4036
4037<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4038
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4039<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4040<tt>ty2</tt> without changing any bits.</p>
4041
4042<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4043
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4044<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Dan Gohman7305fa02008-09-08 16:45:59 +0000[diff] [blame]4045a non-aggregate first class value, and a type to cast it to, which must also be
4046a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
4047<tt>value</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4048and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4049type is a pointer, the destination type must also be a pointer. This
4050instruction supports bitwise conversion of vectors to integers and to vectors
4051of other types (as long as they have the same size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4052
4053<h5>Semantics:</h5>
4054<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4055<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4056this conversion. The conversion is done as if the <tt>value</tt> had been
4057stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
4058converted to other pointer types with this instruction. To convert pointers to
4059other types, use the <a href="#i_inttoptr">inttoptr</a> or
4060<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
4061
4062<h5>Example:</h5>
4063<pre>
4064 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4065 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4066 %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]4067</pre>
4068</div>
4069
4070<!-- ======================================================================= -->
4071<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
4072<div class="doc_text">
4073<p>The instructions in this category are the "miscellaneous"
4074instructions, which defy better classification.</p>
4075</div>
4076
4077<!-- _______________________________________________________________________ -->
4078<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4079</div>
4080<div class="doc_text">
4081<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4082<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]4083</pre>
4084<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4085<p>The '<tt>icmp</tt>' instruction returns a boolean value or
4086a vector of boolean values based on comparison
4087of its two integer, integer vector, or pointer operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4088<h5>Arguments:</h5>
4089<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
4090the condition code indicating the kind of comparison to perform. It is not
4091a value, just a keyword. The possible condition code are:
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4092</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4093<ol>
4094 <li><tt>eq</tt>: equal</li>
4095 <li><tt>ne</tt>: not equal </li>
4096 <li><tt>ugt</tt>: unsigned greater than</li>
4097 <li><tt>uge</tt>: unsigned greater or equal</li>
4098 <li><tt>ult</tt>: unsigned less than</li>
4099 <li><tt>ule</tt>: unsigned less or equal</li>
4100 <li><tt>sgt</tt>: signed greater than</li>
4101 <li><tt>sge</tt>: signed greater or equal</li>
4102 <li><tt>slt</tt>: signed less than</li>
4103 <li><tt>sle</tt>: signed less or equal</li>
4104</ol>
4105<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4106<a href="#t_pointer">pointer</a>
4107or integer <a href="#t_vector">vector</a> typed.
4108They must also be identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4109<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4110<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]4111the condition code given as <tt>cond</tt>. The comparison performed always
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4112yields 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]4113</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4114<ol>
4115 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
4116 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
4117 </li>
4118 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4119 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4120 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4121 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4122 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4123 <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]4124 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4125 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4126 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4127 <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]4128 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4129 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4130 <li><tt>sge</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4131 <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]4132 <li><tt>slt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4133 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4134 <li><tt>sle</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4135 <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]4136</ol>
4137<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
4138values are compared as if they were integers.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4139<p>If the operands are integer vectors, then they are compared
4140element by element. The result is an <tt>i1</tt> vector with
4141the same number of elements as the values being compared.
4142Otherwise, the result is an <tt>i1</tt>.
4143</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4144
4145<h5>Example:</h5>
4146<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
4147 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4148 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4149 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4150 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4151 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4152</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4153
4154<p>Note that the code generator does not yet support vector types with
4155 the <tt>icmp</tt> instruction.</p>
4156
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4157</div>
4158
4159<!-- _______________________________________________________________________ -->
4160<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4161</div>
4162<div class="doc_text">
4163<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4164<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]4165</pre>
4166<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4167<p>The '<tt>fcmp</tt>' instruction returns a boolean value
4168or vector of boolean values based on comparison
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4169of its operands.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4170<p>
4171If the operands are floating point scalars, then the result
4172type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
4173</p>
4174<p>If the operands are floating point vectors, then the result type
4175is a vector of boolean with the same number of elements as the
4176operands being compared.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4177<h5>Arguments:</h5>
4178<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
4179the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4180a value, just a keyword. The possible condition code are:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4181<ol>
4182 <li><tt>false</tt>: no comparison, always returns false</li>
4183 <li><tt>oeq</tt>: ordered and equal</li>
4184 <li><tt>ogt</tt>: ordered and greater than </li>
4185 <li><tt>oge</tt>: ordered and greater than or equal</li>
4186 <li><tt>olt</tt>: ordered and less than </li>
4187 <li><tt>ole</tt>: ordered and less than or equal</li>
4188 <li><tt>one</tt>: ordered and not equal</li>
4189 <li><tt>ord</tt>: ordered (no nans)</li>
4190 <li><tt>ueq</tt>: unordered or equal</li>
4191 <li><tt>ugt</tt>: unordered or greater than </li>
4192 <li><tt>uge</tt>: unordered or greater than or equal</li>
4193 <li><tt>ult</tt>: unordered or less than </li>
4194 <li><tt>ule</tt>: unordered or less than or equal</li>
4195 <li><tt>une</tt>: unordered or not equal</li>
4196 <li><tt>uno</tt>: unordered (either nans)</li>
4197 <li><tt>true</tt>: no comparison, always returns true</li>
4198</ol>
4199<p><i>Ordered</i> means that neither operand is a QNAN while
4200<i>unordered</i> means that either operand may be a QNAN.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4201<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
4202either a <a href="#t_floating">floating point</a> type
4203or a <a href="#t_vector">vector</a> of floating point type.
4204They must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4205<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4206<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4207according to the condition code given as <tt>cond</tt>.
4208If the operands are vectors, then the vectors are compared
4209element by element.
4210Each comparison performed
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4211always yields an <a href="#t_primitive">i1</a> result, as follows:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4212<ol>
4213 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
4214 <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]4215 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4216 <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]4217 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4218 <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]4219 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4220 <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]4221 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4222 <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]4223 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4224 <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]4225 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4226 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
4227 <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]4228 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4229 <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]4230 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4231 <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]4232 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4233 <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]4234 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4235 <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]4236 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4237 <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]4238 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4239 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
4240 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4241</ol>
4242
4243<h5>Example:</h5>
4244<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]4245 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4246 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4247 &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]4248</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4249
4250<p>Note that the code generator does not yet support vector types with
4251 the <tt>fcmp</tt> instruction.</p>
4252
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4253</div>
4254
4255<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4256<div class="doc_subsubsection">
4257 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
4258</div>
4259<div class="doc_text">
4260<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4261<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]4262</pre>
4263<h5>Overview:</h5>
4264<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
4265element-wise comparison of its two integer vector operands.</p>
4266<h5>Arguments:</h5>
4267<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
4268the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4269a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4270<ol>
4271 <li><tt>eq</tt>: equal</li>
4272 <li><tt>ne</tt>: not equal </li>
4273 <li><tt>ugt</tt>: unsigned greater than</li>
4274 <li><tt>uge</tt>: unsigned greater or equal</li>
4275 <li><tt>ult</tt>: unsigned less than</li>
4276 <li><tt>ule</tt>: unsigned less or equal</li>
4277 <li><tt>sgt</tt>: signed greater than</li>
4278 <li><tt>sge</tt>: signed greater or equal</li>
4279 <li><tt>slt</tt>: signed less than</li>
4280 <li><tt>sle</tt>: signed less or equal</li>
4281</ol>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4282<p>The remaining two arguments must be <a href="#t_vector">vector</a> or
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4283<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
4284<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4285<p>The '<tt>vicmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4286according to the condition code given as <tt>cond</tt>. The comparison yields a
4287<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
4288identical type as the values being compared. The most significant bit in each
4289element is 1 if the element-wise comparison evaluates to true, and is 0
4290otherwise. All other bits of the result are undefined. The condition codes
4291are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4292instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4293
4294<h5>Example:</h5>
4295<pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4296 &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>
4297 &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]4298</pre>
4299</div>
4300
4301<!-- _______________________________________________________________________ -->
4302<div class="doc_subsubsection">
4303 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
4304</div>
4305<div class="doc_text">
4306<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4307<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]4308<h5>Overview:</h5>
4309<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
4310element-wise comparison of its two floating point vector operands. The output
4311elements have the same width as the input elements.</p>
4312<h5>Arguments:</h5>
4313<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
4314the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4315a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4316<ol>
4317 <li><tt>false</tt>: no comparison, always returns false</li>
4318 <li><tt>oeq</tt>: ordered and equal</li>
4319 <li><tt>ogt</tt>: ordered and greater than </li>
4320 <li><tt>oge</tt>: ordered and greater than or equal</li>
4321 <li><tt>olt</tt>: ordered and less than </li>
4322 <li><tt>ole</tt>: ordered and less than or equal</li>
4323 <li><tt>one</tt>: ordered and not equal</li>
4324 <li><tt>ord</tt>: ordered (no nans)</li>
4325 <li><tt>ueq</tt>: unordered or equal</li>
4326 <li><tt>ugt</tt>: unordered or greater than </li>
4327 <li><tt>uge</tt>: unordered or greater than or equal</li>
4328 <li><tt>ult</tt>: unordered or less than </li>
4329 <li><tt>ule</tt>: unordered or less than or equal</li>
4330 <li><tt>une</tt>: unordered or not equal</li>
4331 <li><tt>uno</tt>: unordered (either nans)</li>
4332 <li><tt>true</tt>: no comparison, always returns true</li>
4333</ol>
4334<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4335<a href="#t_floating">floating point</a> typed. They must also be identical
4336types.</p>
4337<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4338<p>The '<tt>vfcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4339according to the condition code given as <tt>cond</tt>. The comparison yields a
4340<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4341an identical number of elements as the values being compared, and each element
4342having identical with to the width of the floating point elements. The most
4343significant bit in each element is 1 if the element-wise comparison evaluates to
4344true, and is 0 otherwise. All other bits of the result are undefined. The
4345condition codes are evaluated identically to the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4346<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4347
4348<h5>Example:</h5>
4349<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]4350 <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4351 &lt;result&gt; = vfcmp oeq &lt;2 x float&gt; &lt; float 4, float 0 &gt;, &lt; float 5, float 0 &gt;
4352
4353 <i>; yields: result=&lt;2 x i64&gt; &lt; i64 -1, i64 0 &gt;</i>
4354 &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]4355</pre>
4356</div>
4357
4358<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4359<div class="doc_subsubsection">
4360 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4361</div>
4362
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4363<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4364
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4365<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4366
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4367<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4368<h5>Overview:</h5>
4369<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4370the SSA graph representing the function.</p>
4371<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4372
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4373<p>The type of the incoming values is specified with the first type
4374field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4375as arguments, with one pair for each predecessor basic block of the
4376current block. Only values of <a href="#t_firstclass">first class</a>
4377type may be used as the value arguments to the PHI node. Only labels
4378may be used as the label arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4379
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4380<p>There must be no non-phi instructions between the start of a basic
4381block and the PHI instructions: i.e. PHI instructions must be first in
4382a basic block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4383
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4384<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4385
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4386<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4387specified by the pair corresponding to the predecessor basic block that executed
4388just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4389
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4390<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4391<pre>
4392Loop: ; Infinite loop that counts from 0 on up...
4393 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4394 %nextindvar = add i32 %indvar, 1
4395 br label %Loop
4396</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4397</div>
4398
4399<!-- _______________________________________________________________________ -->
4400<div class="doc_subsubsection">
4401 <a name="i_select">'<tt>select</tt>' Instruction</a>
4402</div>
4403
4404<div class="doc_text">
4405
4406<h5>Syntax:</h5>
4407
4408<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4409 &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>
4410
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4411 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4412</pre>
4413
4414<h5>Overview:</h5>
4415
4416<p>
4417The '<tt>select</tt>' instruction is used to choose one value based on a
4418condition, without branching.
4419</p>
4420
4421
4422<h5>Arguments:</h5>
4423
4424<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4425The '<tt>select</tt>' instruction requires an 'i1' value or
4426a vector of 'i1' values indicating the
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4427condition, and two values of the same <a href="#t_firstclass">first class</a>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4428type. If the val1/val2 are vectors and
4429the condition is a scalar, then entire vectors are selected, not
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4430individual elements.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4431</p>
4432
4433<h5>Semantics:</h5>
4434
4435<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4436If 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]4437value argument; otherwise, it returns the second value argument.
4438</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4439<p>
4440If the condition is a vector of i1, then the value arguments must
4441be vectors of the same size, and the selection is done element
4442by element.
4443</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4444
4445<h5>Example:</h5>
4446
4447<pre>
4448 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4449</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4450
4451<p>Note that the code generator does not yet support conditions
4452 with vector type.</p>
4453
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4454</div>
4455
4456
4457<!-- _______________________________________________________________________ -->
4458<div class="doc_subsubsection">
4459 <a name="i_call">'<tt>call</tt>' Instruction</a>
4460</div>
4461
4462<div class="doc_text">
4463
4464<h5>Syntax:</h5>
4465<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4466 &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]4467</pre>
4468
4469<h5>Overview:</h5>
4470
4471<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4472
4473<h5>Arguments:</h5>
4474
4475<p>This instruction requires several arguments:</p>
4476
4477<ol>
4478 <li>
4479 <p>The optional "tail" marker indicates whether the callee function accesses
4480 any allocas or varargs in the caller. If the "tail" marker is present, the
4481 function call is eligible for tail call optimization. Note that calls may
4482 be marked "tail" even if they do not occur before a <a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4483 href="#i_ret"><tt>ret</tt></a> instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4484 </li>
4485 <li>
4486 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
4487 convention</a> the call should use. If none is specified, the call defaults
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4488 to using C calling conventions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4489 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4490
4491 <li>
4492 <p>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4493 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
4494 and '<tt>inreg</tt>' attributes are valid here.</p>
4495 </li>
4496
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4497 <li>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4498 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4499 the type of the return value. Functions that return no value are marked
4500 <tt><a href="#t_void">void</a></tt>.</p>
4501 </li>
4502 <li>
4503 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4504 value being invoked. The argument types must match the types implied by
4505 this signature. This type can be omitted if the function is not varargs
4506 and if the function type does not return a pointer to a function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4507 </li>
4508 <li>
4509 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4510 be invoked. In most cases, this is a direct function invocation, but
4511 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4512 to function value.</p>
4513 </li>
4514 <li>
4515 <p>'<tt>function args</tt>': argument list whose types match the
4516 function signature argument types. All arguments must be of
4517 <a href="#t_firstclass">first class</a> type. If the function signature
4518 indicates the function accepts a variable number of arguments, the extra
4519 arguments can be specified.</p>
4520 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4521 <li>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4522 <p>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4523 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4524 '<tt>readnone</tt>' attributes are valid here.</p>
4525 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4526</ol>
4527
4528<h5>Semantics:</h5>
4529
4530<p>The '<tt>call</tt>' instruction is used to cause control flow to
4531transfer to a specified function, with its incoming arguments bound to
4532the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4533instruction in the called function, control flow continues with the
4534instruction after the function call, and the return value of the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4535function is bound to the result argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4536
4537<h5>Example:</h5>
4538
4539<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4540 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4541 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4542 %X = tail call i32 @foo() <i>; yields i32</i>
4543 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4544 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4545
4546 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4547 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]4548 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4549 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]4550 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]4551 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4552</pre>
4553
4554</div>
4555
4556<!-- _______________________________________________________________________ -->
4557<div class="doc_subsubsection">
4558 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4559</div>
4560
4561<div class="doc_text">
4562
4563<h5>Syntax:</h5>
4564
4565<pre>
4566 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4567</pre>
4568
4569<h5>Overview:</h5>
4570
4571<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
4572the "variable argument" area of a function call. It is used to implement the
4573<tt>va_arg</tt> macro in C.</p>
4574
4575<h5>Arguments:</h5>
4576
4577<p>This instruction takes a <tt>va_list*</tt> value and the type of
4578the argument. It returns a value of the specified argument type and
4579increments the <tt>va_list</tt> to point to the next argument. The
4580actual type of <tt>va_list</tt> is target specific.</p>
4581
4582<h5>Semantics:</h5>
4583
4584<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4585type from the specified <tt>va_list</tt> and causes the
4586<tt>va_list</tt> to point to the next argument. For more information,
4587see the variable argument handling <a href="#int_varargs">Intrinsic
4588Functions</a>.</p>
4589
4590<p>It is legal for this instruction to be called in a function which does not
4591take a variable number of arguments, for example, the <tt>vfprintf</tt>
4592function.</p>
4593
4594<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
4595href="#intrinsics">intrinsic function</a> because it takes a type as an
4596argument.</p>
4597
4598<h5>Example:</h5>
4599
4600<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4601
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]4602<p>Note that the code generator does not yet fully support va_arg
4603 on many targets. Also, it does not currently support va_arg with
4604 aggregate types on any target.</p>
4605
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4606</div>
4607
4608<!-- *********************************************************************** -->
4609<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4610<!-- *********************************************************************** -->
4611
4612<div class="doc_text">
4613
4614<p>LLVM supports the notion of an "intrinsic function". These functions have
4615well known names and semantics and are required to follow certain restrictions.
4616Overall, these intrinsics represent an extension mechanism for the LLVM
4617language that does not require changing all of the transformations in LLVM when
4618adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
4619
4620<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
4621prefix is reserved in LLVM for intrinsic names; thus, function names may not
4622begin with this prefix. Intrinsic functions must always be external functions:
4623you cannot define the body of intrinsic functions. Intrinsic functions may
4624only be used in call or invoke instructions: it is illegal to take the address
4625of an intrinsic function. Additionally, because intrinsic functions are part
4626of the LLVM language, it is required if any are added that they be documented
4627here.</p>
4628
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4629<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4630a family of functions that perform the same operation but on different data
4631types. Because LLVM can represent over 8 million different integer types,
4632overloading is used commonly to allow an intrinsic function to operate on any
4633integer type. One or more of the argument types or the result type can be
4634overloaded to accept any integer type. Argument types may also be defined as
4635exactly matching a previous argument's type or the result type. This allows an
4636intrinsic function which accepts multiple arguments, but needs all of them to
4637be of the same type, to only be overloaded with respect to a single argument or
4638the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4639
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4640<p>Overloaded intrinsics will have the names of its overloaded argument types
4641encoded into its function name, each preceded by a period. Only those types
4642which are overloaded result in a name suffix. Arguments whose type is matched
4643against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4644take an integer of any width and returns an integer of exactly the same integer
4645width. This leads to a family of functions such as
4646<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4647Only one type, the return type, is overloaded, and only one type suffix is
4648required. Because the argument's type is matched against the return type, it
4649does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4650
4651<p>To learn how to add an intrinsic function, please see the
4652<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
4653</p>
4654
4655</div>
4656
4657<!-- ======================================================================= -->
4658<div class="doc_subsection">
4659 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4660</div>
4661
4662<div class="doc_text">
4663
4664<p>Variable argument support is defined in LLVM with the <a
4665 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4666intrinsic functions. These functions are related to the similarly
4667named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
4668
4669<p>All of these functions operate on arguments that use a
4670target-specific value type "<tt>va_list</tt>". The LLVM assembly
4671language reference manual does not define what this type is, so all
4672transformations should be prepared to handle these functions regardless of
4673the type used.</p>
4674
4675<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
4676instruction and the variable argument handling intrinsic functions are
4677used.</p>
4678
4679<div class="doc_code">
4680<pre>
4681define i32 @test(i32 %X, ...) {
4682 ; Initialize variable argument processing
4683 %ap = alloca i8*
4684 %ap2 = bitcast i8** %ap to i8*
4685 call void @llvm.va_start(i8* %ap2)
4686
4687 ; Read a single integer argument
4688 %tmp = va_arg i8** %ap, i32
4689
4690 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4691 %aq = alloca i8*
4692 %aq2 = bitcast i8** %aq to i8*
4693 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4694 call void @llvm.va_end(i8* %aq2)
4695
4696 ; Stop processing of arguments.
4697 call void @llvm.va_end(i8* %ap2)
4698 ret i32 %tmp
4699}
4700
4701declare void @llvm.va_start(i8*)
4702declare void @llvm.va_copy(i8*, i8*)
4703declare void @llvm.va_end(i8*)
4704</pre>
4705</div>
4706
4707</div>
4708
4709<!-- _______________________________________________________________________ -->
4710<div class="doc_subsubsection">
4711 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4712</div>
4713
4714
4715<div class="doc_text">
4716<h5>Syntax:</h5>
4717<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
4718<h5>Overview:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4719<p>The '<tt>llvm.va_start</tt>' intrinsic initializes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4720<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4721href="#i_va_arg">va_arg</a></tt>.</p>
4722
4723<h5>Arguments:</h5>
4724
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4725<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]4726
4727<h5>Semantics:</h5>
4728
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4729<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]4730macro available in C. In a target-dependent way, it initializes the
4731<tt>va_list</tt> element to which the argument points, so that the next call to
4732<tt>va_arg</tt> will produce the first variable argument passed to the function.
4733Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
4734last argument of the function as the compiler can figure that out.</p>
4735
4736</div>
4737
4738<!-- _______________________________________________________________________ -->
4739<div class="doc_subsubsection">
4740 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
4741</div>
4742
4743<div class="doc_text">
4744<h5>Syntax:</h5>
4745<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
4746<h5>Overview:</h5>
4747
4748<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
4749which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
4750or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
4751
4752<h5>Arguments:</h5>
4753
4754<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
4755
4756<h5>Semantics:</h5>
4757
4758<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
4759macro available in C. In a target-dependent way, it destroys the
4760<tt>va_list</tt> element to which the argument points. Calls to <a
4761href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4762<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4763<tt>llvm.va_end</tt>.</p>
4764
4765</div>
4766
4767<!-- _______________________________________________________________________ -->
4768<div class="doc_subsubsection">
4769 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
4770</div>
4771
4772<div class="doc_text">
4773
4774<h5>Syntax:</h5>
4775
4776<pre>
4777 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
4778</pre>
4779
4780<h5>Overview:</h5>
4781
4782<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4783from the source argument list to the destination argument list.</p>
4784
4785<h5>Arguments:</h5>
4786
4787<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
4788The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
4789
4790
4791<h5>Semantics:</h5>
4792
4793<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4794macro available in C. In a target-dependent way, it copies the source
4795<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4796intrinsic is necessary because the <tt><a href="#int_va_start">
4797llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4798example, memory allocation.</p>
4799
4800</div>
4801
4802<!-- ======================================================================= -->
4803<div class="doc_subsection">
4804 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4805</div>
4806
4807<div class="doc_text">
4808
4809<p>
4810LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]4811Collection</a> (GC) requires the implementation and generation of these
4812intrinsics.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4813These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
4814stack</a>, as well as garbage collector implementations that require <a
4815href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
4816Front-ends for type-safe garbage collected languages should generate these
4817intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4818href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4819</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]4820
4821<p>The garbage collection intrinsics only operate on objects in the generic
4822 address space (address space zero).</p>
4823
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4824</div>
4825
4826<!-- _______________________________________________________________________ -->
4827<div class="doc_subsubsection">
4828 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
4829</div>
4830
4831<div class="doc_text">
4832
4833<h5>Syntax:</h5>
4834
4835<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4836 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4837</pre>
4838
4839<h5>Overview:</h5>
4840
4841<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
4842the code generator, and allows some metadata to be associated with it.</p>
4843
4844<h5>Arguments:</h5>
4845
4846<p>The first argument specifies the address of a stack object that contains the
4847root pointer. The second pointer (which must be either a constant or a global
4848value address) contains the meta-data to be associated with the root.</p>
4849
4850<h5>Semantics:</h5>
4851
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]4852<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]4853location. At compile-time, the code generator generates information to allow
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4854the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4855intrinsic may only be used in a function which <a href="#gc">specifies a GC
4856algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4857
4858</div>
4859
4860
4861<!-- _______________________________________________________________________ -->
4862<div class="doc_subsubsection">
4863 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
4864</div>
4865
4866<div class="doc_text">
4867
4868<h5>Syntax:</h5>
4869
4870<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4871 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4872</pre>
4873
4874<h5>Overview:</h5>
4875
4876<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4877locations, allowing garbage collector implementations that require read
4878barriers.</p>
4879
4880<h5>Arguments:</h5>
4881
4882<p>The second argument is the address to read from, which should be an address
4883allocated from the garbage collector. The first object is a pointer to the
4884start of the referenced object, if needed by the language runtime (otherwise
4885null).</p>
4886
4887<h5>Semantics:</h5>
4888
4889<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4890instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4891garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4892may only be used in a function which <a href="#gc">specifies a GC
4893algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4894
4895</div>
4896
4897
4898<!-- _______________________________________________________________________ -->
4899<div class="doc_subsubsection">
4900 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
4901</div>
4902
4903<div class="doc_text">
4904
4905<h5>Syntax:</h5>
4906
4907<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4908 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4909</pre>
4910
4911<h5>Overview:</h5>
4912
4913<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4914locations, allowing garbage collector implementations that require write
4915barriers (such as generational or reference counting collectors).</p>
4916
4917<h5>Arguments:</h5>
4918
4919<p>The first argument is the reference to store, the second is the start of the
4920object to store it to, and the third is the address of the field of Obj to
4921store to. If the runtime does not require a pointer to the object, Obj may be
4922null.</p>
4923
4924<h5>Semantics:</h5>
4925
4926<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4927instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4928garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4929may only be used in a function which <a href="#gc">specifies a GC
4930algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4931
4932</div>
4933
4934
4935
4936<!-- ======================================================================= -->
4937<div class="doc_subsection">
4938 <a name="int_codegen">Code Generator Intrinsics</a>
4939</div>
4940
4941<div class="doc_text">
4942<p>
4943These intrinsics are provided by LLVM to expose special features that may only
4944be implemented with code generator support.
4945</p>
4946
4947</div>
4948
4949<!-- _______________________________________________________________________ -->
4950<div class="doc_subsubsection">
4951 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
4952</div>
4953
4954<div class="doc_text">
4955
4956<h5>Syntax:</h5>
4957<pre>
4958 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
4959</pre>
4960
4961<h5>Overview:</h5>
4962
4963<p>
4964The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4965target-specific value indicating the return address of the current function
4966or one of its callers.
4967</p>
4968
4969<h5>Arguments:</h5>
4970
4971<p>
4972The argument to this intrinsic indicates which function to return the address
4973for. Zero indicates the calling function, one indicates its caller, etc. The
4974argument is <b>required</b> to be a constant integer value.
4975</p>
4976
4977<h5>Semantics:</h5>
4978
4979<p>
4980The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4981the return address of the specified call frame, or zero if it cannot be
4982identified. The value returned by this intrinsic is likely to be incorrect or 0
4983for arguments other than zero, so it should only be used for debugging purposes.
4984</p>
4985
4986<p>
4987Note that calling this intrinsic does not prevent function inlining or other
4988aggressive transformations, so the value returned may not be that of the obvious
4989source-language caller.
4990</p>
4991</div>
4992
4993
4994<!-- _______________________________________________________________________ -->
4995<div class="doc_subsubsection">
4996 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
4997</div>
4998
4999<div class="doc_text">
5000
5001<h5>Syntax:</h5>
5002<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5003 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5004</pre>
5005
5006<h5>Overview:</h5>
5007
5008<p>
5009The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5010target-specific frame pointer value for the specified stack frame.
5011</p>
5012
5013<h5>Arguments:</h5>
5014
5015<p>
5016The argument to this intrinsic indicates which function to return the frame
5017pointer for. Zero indicates the calling function, one indicates its caller,
5018etc. The argument is <b>required</b> to be a constant integer value.
5019</p>
5020
5021<h5>Semantics:</h5>
5022
5023<p>
5024The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
5025the frame address of the specified call frame, or zero if it cannot be
5026identified. The value returned by this intrinsic is likely to be incorrect or 0
5027for arguments other than zero, so it should only be used for debugging purposes.
5028</p>
5029
5030<p>
5031Note that calling this intrinsic does not prevent function inlining or other
5032aggressive transformations, so the value returned may not be that of the obvious
5033source-language caller.
5034</p>
5035</div>
5036
5037<!-- _______________________________________________________________________ -->
5038<div class="doc_subsubsection">
5039 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5040</div>
5041
5042<div class="doc_text">
5043
5044<h5>Syntax:</h5>
5045<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5046 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5047</pre>
5048
5049<h5>Overview:</h5>
5050
5051<p>
5052The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
5053the function stack, for use with <a href="#int_stackrestore">
5054<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
5055features like scoped automatic variable sized arrays in C99.
5056</p>
5057
5058<h5>Semantics:</h5>
5059
5060<p>
5061This intrinsic returns a opaque pointer value that can be passed to <a
5062href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
5063<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
5064<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
5065state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
5066practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
5067that were allocated after the <tt>llvm.stacksave</tt> was executed.
5068</p>
5069
5070</div>
5071
5072<!-- _______________________________________________________________________ -->
5073<div class="doc_subsubsection">
5074 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5075</div>
5076
5077<div class="doc_text">
5078
5079<h5>Syntax:</h5>
5080<pre>
5081 declare void @llvm.stackrestore(i8 * %ptr)
5082</pre>
5083
5084<h5>Overview:</h5>
5085
5086<p>
5087The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5088the function stack to the state it was in when the corresponding <a
5089href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
5090useful for implementing language features like scoped automatic variable sized
5091arrays in C99.
5092</p>
5093
5094<h5>Semantics:</h5>
5095
5096<p>
5097See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
5098</p>
5099
5100</div>
5101
5102
5103<!-- _______________________________________________________________________ -->
5104<div class="doc_subsubsection">
5105 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5106</div>
5107
5108<div class="doc_text">
5109
5110<h5>Syntax:</h5>
5111<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5112 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]5113</pre>
5114
5115<h5>Overview:</h5>
5116
5117
5118<p>
5119The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
5120a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
5121no
5122effect on the behavior of the program but can change its performance
5123characteristics.
5124</p>
5125
5126<h5>Arguments:</h5>
5127
5128<p>
5129<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
5130determining if the fetch should be for a read (0) or write (1), and
5131<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5132locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
5133<tt>locality</tt> arguments must be constant integers.
5134</p>
5135
5136<h5>Semantics:</h5>
5137
5138<p>
5139This intrinsic does not modify the behavior of the program. In particular,
5140prefetches cannot trap and do not produce a value. On targets that support this
5141intrinsic, the prefetch can provide hints to the processor cache for better
5142performance.
5143</p>
5144
5145</div>
5146
5147<!-- _______________________________________________________________________ -->
5148<div class="doc_subsubsection">
5149 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5150</div>
5151
5152<div class="doc_text">
5153
5154<h5>Syntax:</h5>
5155<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5156 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5157</pre>
5158
5159<h5>Overview:</h5>
5160
5161
5162<p>
5163The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5164(PC) in a region of
5165code to simulators and other tools. The method is target specific, but it is
5166expected that the marker will use exported symbols to transmit the PC of the
5167marker.
5168The marker makes no guarantees that it will remain with any specific instruction
5169after optimizations. It is possible that the presence of a marker will inhibit
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5170optimizations. The intended use is to be inserted after optimizations to allow
5171correlations of simulation runs.
5172</p>
5173
5174<h5>Arguments:</h5>
5175
5176<p>
5177<tt>id</tt> is a numerical id identifying the marker.
5178</p>
5179
5180<h5>Semantics:</h5>
5181
5182<p>
5183This intrinsic does not modify the behavior of the program. Backends that do not
5184support this intrinisic may ignore it.
5185</p>
5186
5187</div>
5188
5189<!-- _______________________________________________________________________ -->
5190<div class="doc_subsubsection">
5191 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5192</div>
5193
5194<div class="doc_text">
5195
5196<h5>Syntax:</h5>
5197<pre>
5198 declare i64 @llvm.readcyclecounter( )
5199</pre>
5200
5201<h5>Overview:</h5>
5202
5203
5204<p>
5205The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5206counter register (or similar low latency, high accuracy clocks) on those targets
5207that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
5208As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
5209should only be used for small timings.
5210</p>
5211
5212<h5>Semantics:</h5>
5213
5214<p>
5215When directly supported, reading the cycle counter should not modify any memory.
5216Implementations are allowed to either return a application specific value or a
5217system wide value. On backends without support, this is lowered to a constant 0.
5218</p>
5219
5220</div>
5221
5222<!-- ======================================================================= -->
5223<div class="doc_subsection">
5224 <a name="int_libc">Standard C Library Intrinsics</a>
5225</div>
5226
5227<div class="doc_text">
5228<p>
5229LLVM provides intrinsics for a few important standard C library functions.
5230These intrinsics allow source-language front-ends to pass information about the
5231alignment of the pointer arguments to the code generator, providing opportunity
5232for more efficient code generation.
5233</p>
5234
5235</div>
5236
5237<!-- _______________________________________________________________________ -->
5238<div class="doc_subsubsection">
5239 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5240</div>
5241
5242<div class="doc_text">
5243
5244<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5245<p>This is an overloaded intrinsic. You can use llvm.memcpy on any integer bit
5246width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5247<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5248 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5249 i8 &lt;len&gt;, i32 &lt;align&gt;)
5250 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5251 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5252 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5253 i32 &lt;len&gt;, i32 &lt;align&gt;)
5254 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5255 i64 &lt;len&gt;, i32 &lt;align&gt;)
5256</pre>
5257
5258<h5>Overview:</h5>
5259
5260<p>
5261The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5262location to the destination location.
5263</p>
5264
5265<p>
5266Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5267intrinsics do not return a value, and takes an extra alignment argument.
5268</p>
5269
5270<h5>Arguments:</h5>
5271
5272<p>
5273The first argument is a pointer to the destination, the second is a pointer to
5274the source. The third argument is an integer argument
5275specifying the number of bytes to copy, and the fourth argument is the alignment
5276of the source and destination locations.
5277</p>
5278
5279<p>
5280If the call to this intrinisic has an alignment value that is not 0 or 1, then
5281the caller guarantees that both the source and destination pointers are aligned
5282to that boundary.
5283</p>
5284
5285<h5>Semantics:</h5>
5286
5287<p>
5288The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5289location to the destination location, which are not allowed to overlap. It
5290copies "len" bytes of memory over. If the argument is known to be aligned to
5291some boundary, this can be specified as the fourth argument, otherwise it should
5292be set to 0 or 1.
5293</p>
5294</div>
5295
5296
5297<!-- _______________________________________________________________________ -->
5298<div class="doc_subsubsection">
5299 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5300</div>
5301
5302<div class="doc_text">
5303
5304<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5305<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
5306width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5307<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5308 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5309 i8 &lt;len&gt;, i32 &lt;align&gt;)
5310 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5311 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5312 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5313 i32 &lt;len&gt;, i32 &lt;align&gt;)
5314 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5315 i64 &lt;len&gt;, i32 &lt;align&gt;)
5316</pre>
5317
5318<h5>Overview:</h5>
5319
5320<p>
5321The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5322location to the destination location. It is similar to the
Chris Lattnerdba16ea2008-01-06 19:51:52 +0000[diff] [blame]5323'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5324</p>
5325
5326<p>
5327Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5328intrinsics do not return a value, and takes an extra alignment argument.
5329</p>
5330
5331<h5>Arguments:</h5>
5332
5333<p>
5334The first argument is a pointer to the destination, the second is a pointer to
5335the source. The third argument is an integer argument
5336specifying the number of bytes to copy, and the fourth argument is the alignment
5337of the source and destination locations.
5338</p>
5339
5340<p>
5341If the call to this intrinisic has an alignment value that is not 0 or 1, then
5342the caller guarantees that the source and destination pointers are aligned to
5343that boundary.
5344</p>
5345
5346<h5>Semantics:</h5>
5347
5348<p>
5349The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
5350location to the destination location, which may overlap. It
5351copies "len" bytes of memory over. If the argument is known to be aligned to
5352some boundary, this can be specified as the fourth argument, otherwise it should
5353be set to 0 or 1.
5354</p>
5355</div>
5356
5357
5358<!-- _______________________________________________________________________ -->
5359<div class="doc_subsubsection">
5360 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5361</div>
5362
5363<div class="doc_text">
5364
5365<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5366<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
5367width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5368<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5369 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5370 i8 &lt;len&gt;, i32 &lt;align&gt;)
5371 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5372 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5373 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5374 i32 &lt;len&gt;, i32 &lt;align&gt;)
5375 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5376 i64 &lt;len&gt;, i32 &lt;align&gt;)
5377</pre>
5378
5379<h5>Overview:</h5>
5380
5381<p>
5382The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
5383byte value.
5384</p>
5385
5386<p>
5387Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5388does not return a value, and takes an extra alignment argument.
5389</p>
5390
5391<h5>Arguments:</h5>
5392
5393<p>
5394The first argument is a pointer to the destination to fill, the second is the
5395byte value to fill it with, the third argument is an integer
5396argument specifying the number of bytes to fill, and the fourth argument is the
5397known alignment of destination location.
5398</p>
5399
5400<p>
5401If the call to this intrinisic has an alignment value that is not 0 or 1, then
5402the caller guarantees that the destination pointer is aligned to that boundary.
5403</p>
5404
5405<h5>Semantics:</h5>
5406
5407<p>
5408The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5409the
5410destination location. If the argument is known to be aligned to some boundary,
5411this can be specified as the fourth argument, otherwise it should be set to 0 or
54121.
5413</p>
5414</div>
5415
5416
5417<!-- _______________________________________________________________________ -->
5418<div class="doc_subsubsection">
5419 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5420</div>
5421
5422<div class="doc_text">
5423
5424<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5425<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]5426floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5427types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5428<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5429 declare float @llvm.sqrt.f32(float %Val)
5430 declare double @llvm.sqrt.f64(double %Val)
5431 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5432 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5433 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5434</pre>
5435
5436<h5>Overview:</h5>
5437
5438<p>
5439The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5440returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5441<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattnerf914a002008-01-29 07:00:44 +0000[diff] [blame]5442negative numbers other than -0.0 (which allows for better optimization, because
5443there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5444defined to return -0.0 like IEEE sqrt.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5445</p>
5446
5447<h5>Arguments:</h5>
5448
5449<p>
5450The argument and return value are floating point numbers of the same type.
5451</p>
5452
5453<h5>Semantics:</h5>
5454
5455<p>
5456This function returns the sqrt of the specified operand if it is a nonnegative
5457floating point number.
5458</p>
5459</div>
5460
5461<!-- _______________________________________________________________________ -->
5462<div class="doc_subsubsection">
5463 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5464</div>
5465
5466<div class="doc_text">
5467
5468<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5469<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]5470floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5471types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5472<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5473 declare float @llvm.powi.f32(float %Val, i32 %power)
5474 declare double @llvm.powi.f64(double %Val, i32 %power)
5475 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5476 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5477 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5478</pre>
5479
5480<h5>Overview:</h5>
5481
5482<p>
5483The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5484specified (positive or negative) power. The order of evaluation of
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5485multiplications is not defined. When a vector of floating point type is
5486used, the second argument remains a scalar integer value.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5487</p>
5488
5489<h5>Arguments:</h5>
5490
5491<p>
5492The second argument is an integer power, and the first is a value to raise to
5493that power.
5494</p>
5495
5496<h5>Semantics:</h5>
5497
5498<p>
5499This function returns the first value raised to the second power with an
5500unspecified sequence of rounding operations.</p>
5501</div>
5502
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5503<!-- _______________________________________________________________________ -->
5504<div class="doc_subsubsection">
5505 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5506</div>
5507
5508<div class="doc_text">
5509
5510<h5>Syntax:</h5>
5511<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5512floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5513types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5514<pre>
5515 declare float @llvm.sin.f32(float %Val)
5516 declare double @llvm.sin.f64(double %Val)
5517 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5518 declare fp128 @llvm.sin.f128(fp128 %Val)
5519 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5520</pre>
5521
5522<h5>Overview:</h5>
5523
5524<p>
5525The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5526</p>
5527
5528<h5>Arguments:</h5>
5529
5530<p>
5531The argument and return value are floating point numbers of the same type.
5532</p>
5533
5534<h5>Semantics:</h5>
5535
5536<p>
5537This function returns the sine of the specified operand, returning the
5538same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5539conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5540</div>
5541
5542<!-- _______________________________________________________________________ -->
5543<div class="doc_subsubsection">
5544 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5545</div>
5546
5547<div class="doc_text">
5548
5549<h5>Syntax:</h5>
5550<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5551floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5552types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5553<pre>
5554 declare float @llvm.cos.f32(float %Val)
5555 declare double @llvm.cos.f64(double %Val)
5556 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5557 declare fp128 @llvm.cos.f128(fp128 %Val)
5558 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5559</pre>
5560
5561<h5>Overview:</h5>
5562
5563<p>
5564The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5565</p>
5566
5567<h5>Arguments:</h5>
5568
5569<p>
5570The argument and return value are floating point numbers of the same type.
5571</p>
5572
5573<h5>Semantics:</h5>
5574
5575<p>
5576This function returns the cosine of the specified operand, returning the
5577same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5578conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5579</div>
5580
5581<!-- _______________________________________________________________________ -->
5582<div class="doc_subsubsection">
5583 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5584</div>
5585
5586<div class="doc_text">
5587
5588<h5>Syntax:</h5>
5589<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5590floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5591types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5592<pre>
5593 declare float @llvm.pow.f32(float %Val, float %Power)
5594 declare double @llvm.pow.f64(double %Val, double %Power)
5595 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5596 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5597 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5598</pre>
5599
5600<h5>Overview:</h5>
5601
5602<p>
5603The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5604specified (positive or negative) power.
5605</p>
5606
5607<h5>Arguments:</h5>
5608
5609<p>
5610The second argument is a floating point power, and the first is a value to
5611raise to that power.
5612</p>
5613
5614<h5>Semantics:</h5>
5615
5616<p>
5617This function returns the first value raised to the second power,
5618returning the
5619same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5620conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5621</div>
5622
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5623
5624<!-- ======================================================================= -->
5625<div class="doc_subsection">
5626 <a name="int_manip">Bit Manipulation Intrinsics</a>
5627</div>
5628
5629<div class="doc_text">
5630<p>
5631LLVM provides intrinsics for a few important bit manipulation operations.
5632These allow efficient code generation for some algorithms.
5633</p>
5634
5635</div>
5636
5637<!-- _______________________________________________________________________ -->
5638<div class="doc_subsubsection">
5639 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5640</div>
5641
5642<div class="doc_text">
5643
5644<h5>Syntax:</h5>
5645<p>This is an overloaded intrinsic function. You can use bswap on any integer
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5646type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5647<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5648 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5649 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5650 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5651</pre>
5652
5653<h5>Overview:</h5>
5654
5655<p>
5656The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5657values with an even number of bytes (positive multiple of 16 bits). These are
5658useful for performing operations on data that is not in the target's native
5659byte order.
5660</p>
5661
5662<h5>Semantics:</h5>
5663
5664<p>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5665The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5666and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5667intrinsic returns an i32 value that has the four bytes of the input i32
5668swapped, 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]5669i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5670<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5671additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
5672</p>
5673
5674</div>
5675
5676<!-- _______________________________________________________________________ -->
5677<div class="doc_subsubsection">
5678 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5679</div>
5680
5681<div class="doc_text">
5682
5683<h5>Syntax:</h5>
5684<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]5685width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5686<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5687 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
5688 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5689 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5690 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5691 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5692</pre>
5693
5694<h5>Overview:</h5>
5695
5696<p>
5697The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5698value.
5699</p>
5700
5701<h5>Arguments:</h5>
5702
5703<p>
5704The only argument is the value to be counted. The argument may be of any
5705integer type. The return type must match the argument type.
5706</p>
5707
5708<h5>Semantics:</h5>
5709
5710<p>
5711The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5712</p>
5713</div>
5714
5715<!-- _______________________________________________________________________ -->
5716<div class="doc_subsubsection">
5717 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5718</div>
5719
5720<div class="doc_text">
5721
5722<h5>Syntax:</h5>
5723<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]5724integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5725<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5726 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5727 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5728 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5729 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5730 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5731</pre>
5732
5733<h5>Overview:</h5>
5734
5735<p>
5736The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5737leading zeros in a variable.
5738</p>
5739
5740<h5>Arguments:</h5>
5741
5742<p>
5743The only argument is the value to be counted. The argument may be of any
5744integer type. The return type must match the argument type.
5745</p>
5746
5747<h5>Semantics:</h5>
5748
5749<p>
5750The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5751in a variable. If the src == 0 then the result is the size in bits of the type
5752of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
5753</p>
5754</div>
5755
5756
5757
5758<!-- _______________________________________________________________________ -->
5759<div class="doc_subsubsection">
5760 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5761</div>
5762
5763<div class="doc_text">
5764
5765<h5>Syntax:</h5>
5766<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]5767integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5768<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5769 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5770 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5771 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5772 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5773 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5774</pre>
5775
5776<h5>Overview:</h5>
5777
5778<p>
5779The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5780trailing zeros.
5781</p>
5782
5783<h5>Arguments:</h5>
5784
5785<p>
5786The only argument is the value to be counted. The argument may be of any
5787integer type. The return type must match the argument type.
5788</p>
5789
5790<h5>Semantics:</h5>
5791
5792<p>
5793The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5794in a variable. If the src == 0 then the result is the size in bits of the type
5795of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5796</p>
5797</div>
5798
5799<!-- _______________________________________________________________________ -->
5800<div class="doc_subsubsection">
5801 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
5802</div>
5803
5804<div class="doc_text">
5805
5806<h5>Syntax:</h5>
5807<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5808on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5809<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5810 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5811 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5812</pre>
5813
5814<h5>Overview:</h5>
5815<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
5816range of bits from an integer value and returns them in the same bit width as
5817the original value.</p>
5818
5819<h5>Arguments:</h5>
5820<p>The first argument, <tt>%val</tt> and the result may be integer types of
5821any bit width but they must have the same bit width. The second and third
5822arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
5823
5824<h5>Semantics:</h5>
5825<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
5826of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5827<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5828operates in forward mode.</p>
5829<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5830right by <tt>%loBit</tt> bits and then ANDing it with a mask with
5831only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5832<ol>
5833 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5834 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5835 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5836 to determine the number of bits to retain.</li>
5837 <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]5838 <li>The mask is ANDed with <tt>%val</tt> to produce the result.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5839</ol>
5840<p>In reverse mode, a similar computation is made except that the bits are
5841returned in the reverse order. So, for example, if <tt>X</tt> has the value
5842<tt>i16 0x0ACF (101011001111)</tt> and we apply
5843<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5844<tt>i16 0x0026 (000000100110)</tt>.</p>
5845</div>
5846
5847<div class="doc_subsubsection">
5848 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5849</div>
5850
5851<div class="doc_text">
5852
5853<h5>Syntax:</h5>
5854<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5855on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5856<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5857 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5858 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]5859</pre>
5860
5861<h5>Overview:</h5>
5862<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5863of bits in an integer value with another integer value. It returns the integer
5864with the replaced bits.</p>
5865
5866<h5>Arguments:</h5>
5867<p>The first argument, <tt>%val</tt> and the result may be integer types of
5868any bit width but they must have the same bit width. <tt>%val</tt> is the value
5869whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5870integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5871type since they specify only a bit index.</p>
5872
5873<h5>Semantics:</h5>
5874<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5875of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5876<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5877operates in forward mode.</p>
5878<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5879truncating it down to the size of the replacement area or zero extending it
5880up to that size.</p>
5881<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5882are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5883in <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]5884to the <tt>%hi</tt>th bit.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5885<p>In reverse mode, a similar computation is made except that the bits are
5886reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5887<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5888<h5>Examples:</h5>
5889<pre>
5890 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
5891 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5892 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5893 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
5894 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
5895</pre>
5896</div>
5897
5898<!-- ======================================================================= -->
5899<div class="doc_subsection">
5900 <a name="int_debugger">Debugger Intrinsics</a>
5901</div>
5902
5903<div class="doc_text">
5904<p>
5905The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5906are described in the <a
5907href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5908Debugging</a> document.
5909</p>
5910</div>
5911
5912
5913<!-- ======================================================================= -->
5914<div class="doc_subsection">
5915 <a name="int_eh">Exception Handling Intrinsics</a>
5916</div>
5917
5918<div class="doc_text">
5919<p> The LLVM exception handling intrinsics (which all start with
5920<tt>llvm.eh.</tt> prefix), are described in the <a
5921href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5922Handling</a> document. </p>
5923</div>
5924
5925<!-- ======================================================================= -->
5926<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5927 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5928</div>
5929
5930<div class="doc_text">
5931<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5932 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5933 the <tt>nest</tt> attribute, from a function. The result is a callable
5934 function pointer lacking the nest parameter - the caller does not need
5935 to provide a value for it. Instead, the value to use is stored in
5936 advance in a "trampoline", a block of memory usually allocated
5937 on the stack, which also contains code to splice the nest value into the
5938 argument list. This is used to implement the GCC nested function address
5939 extension.
5940</p>
5941<p>
5942 For example, if the function is
5943 <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]5944 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]5945<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5946 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5947 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5948 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5949 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5950</pre>
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]5951 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5952 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5953</div>
5954
5955<!-- _______________________________________________________________________ -->
5956<div class="doc_subsubsection">
5957 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5958</div>
5959<div class="doc_text">
5960<h5>Syntax:</h5>
5961<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5962declare 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]5963</pre>
5964<h5>Overview:</h5>
5965<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5966 This fills the memory pointed to by <tt>tramp</tt> with code
5967 and returns a function pointer suitable for executing it.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5968</p>
5969<h5>Arguments:</h5>
5970<p>
5971 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5972 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5973 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sands35012212007-08-22 23:39:54 +0000[diff] [blame]5974 intrinsic. Note that the size and the alignment are target-specific - LLVM
5975 currently provides no portable way of determining them, so a front-end that
5976 generates this intrinsic needs to have some target-specific knowledge.
5977 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]5978</p>
5979<h5>Semantics:</h5>
5980<p>
5981 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5982 dependent code, turning it into a function. A pointer to this function is
5983 returned, but needs to be bitcast to an
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5984 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5985 before being called. The new function's signature is the same as that of
5986 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5987 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5988 of pointer type. Calling the new function is equivalent to calling
5989 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5990 missing <tt>nest</tt> argument. If, after calling
5991 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5992 modified, then the effect of any later call to the returned function pointer is
5993 undefined.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5994</p>
5995</div>
5996
5997<!-- ======================================================================= -->
5998<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5999 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6000</div>
6001
6002<div class="doc_text">
6003<p>
6004 These intrinsic functions expand the "universal IR" of LLVM to represent
6005 hardware constructs for atomic operations and memory synchronization. This
6006 provides an interface to the hardware, not an interface to the programmer. It
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]6007 is aimed at a low enough level to allow any programming models or APIs
6008 (Application Programming Interfaces) which
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6009 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
6010 hardware behavior. Just as hardware provides a "universal IR" for source
6011 languages, it also provides a starting point for developing a "universal"
6012 atomic operation and synchronization IR.
6013</p>
6014<p>
6015 These do <em>not</em> form an API such as high-level threading libraries,
6016 software transaction memory systems, atomic primitives, and intrinsic
6017 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6018 application libraries. The hardware interface provided by LLVM should allow
6019 a clean implementation of all of these APIs and parallel programming models.
6020 No one model or paradigm should be selected above others unless the hardware
6021 itself ubiquitously does so.
6022
6023</p>
6024</div>
6025
6026<!-- _______________________________________________________________________ -->
6027<div class="doc_subsubsection">
6028 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6029</div>
6030<div class="doc_text">
6031<h5>Syntax:</h5>
6032<pre>
6033declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
6034i1 &lt;device&gt; )
6035
6036</pre>
6037<h5>Overview:</h5>
6038<p>
6039 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6040 specific pairs of memory access types.
6041</p>
6042<h5>Arguments:</h5>
6043<p>
6044 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6045 The first four arguments enables a specific barrier as listed below. The fith
6046 argument specifies that the barrier applies to io or device or uncached memory.
6047
6048</p>
6049 <ul>
6050 <li><tt>ll</tt>: load-load barrier</li>
6051 <li><tt>ls</tt>: load-store barrier</li>
6052 <li><tt>sl</tt>: store-load barrier</li>
6053 <li><tt>ss</tt>: store-store barrier</li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6054 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6055 </ul>
6056<h5>Semantics:</h5>
6057<p>
6058 This intrinsic causes the system to enforce some ordering constraints upon
6059 the loads and stores of the program. This barrier does not indicate
6060 <em>when</em> any events will occur, it only enforces an <em>order</em> in
6061 which they occur. For any of the specified pairs of load and store operations
6062 (f.ex. load-load, or store-load), all of the first operations preceding the
6063 barrier will complete before any of the second operations succeeding the
6064 barrier begin. Specifically the semantics for each pairing is as follows:
6065</p>
6066 <ul>
6067 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6068 after the barrier begins.</li>
6069
6070 <li><tt>ls</tt>: All loads before the barrier must complete before any
6071 store after the barrier begins.</li>
6072 <li><tt>ss</tt>: All stores before the barrier must complete before any
6073 store after the barrier begins.</li>
6074 <li><tt>sl</tt>: All stores before the barrier must complete before any
6075 load after the barrier begins.</li>
6076 </ul>
6077<p>
6078 These semantics are applied with a logical "and" behavior when more than one
6079 is enabled in a single memory barrier intrinsic.
6080</p>
6081<p>
6082 Backends may implement stronger barriers than those requested when they do not
6083 support as fine grained a barrier as requested. Some architectures do not
6084 need all types of barriers and on such architectures, these become noops.
6085</p>
6086<h5>Example:</h5>
6087<pre>
6088%ptr = malloc i32
6089 store i32 4, %ptr
6090
6091%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6092 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6093 <i>; guarantee the above finishes</i>
6094 store i32 8, %ptr <i>; before this begins</i>
6095</pre>
6096</div>
6097
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6098<!-- _______________________________________________________________________ -->
6099<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6100 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6101</div>
6102<div class="doc_text">
6103<h5>Syntax:</h5>
6104<p>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6105 This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6106 any integer bit width and for different address spaces. Not all targets
6107 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6108
6109<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6110declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6111declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6112declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6113declare 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]6114
6115</pre>
6116<h5>Overview:</h5>
6117<p>
6118 This loads a value in memory and compares it to a given value. If they are
6119 equal, it stores a new value into the memory.
6120</p>
6121<h5>Arguments:</h5>
6122<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6123 The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6124 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6125 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6126 this integer type. While any bit width integer may be used, targets may only
6127 lower representations they support in hardware.
6128
6129</p>
6130<h5>Semantics:</h5>
6131<p>
6132 This entire intrinsic must be executed atomically. It first loads the value
6133 in memory pointed to by <tt>ptr</tt> and compares it with the value
6134 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
6135 loaded value is yielded in all cases. This provides the equivalent of an
6136 atomic compare-and-swap operation within the SSA framework.
6137</p>
6138<h5>Examples:</h5>
6139
6140<pre>
6141%ptr = malloc i32
6142 store i32 4, %ptr
6143
6144%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6145%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6146 <i>; yields {i32}:result1 = 4</i>
6147%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6148%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6149
6150%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6151%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6152 <i>; yields {i32}:result2 = 8</i>
6153%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6154
6155%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6156</pre>
6157</div>
6158
6159<!-- _______________________________________________________________________ -->
6160<div class="doc_subsubsection">
6161 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6162</div>
6163<div class="doc_text">
6164<h5>Syntax:</h5>
6165
6166<p>
6167 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6168 integer bit width. Not all targets support all bit widths however.</p>
6169<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6170declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6171declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6172declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6173declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6174
6175</pre>
6176<h5>Overview:</h5>
6177<p>
6178 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6179 the value from memory. It then stores the value in <tt>val</tt> in the memory
6180 at <tt>ptr</tt>.
6181</p>
6182<h5>Arguments:</h5>
6183
6184<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6185 The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6186 <tt>val</tt> argument and the result must be integers of the same bit width.
6187 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6188 integer type. The targets may only lower integer representations they
6189 support.
6190</p>
6191<h5>Semantics:</h5>
6192<p>
6193 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6194 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6195 equivalent of an atomic swap operation within the SSA framework.
6196
6197</p>
6198<h5>Examples:</h5>
6199<pre>
6200%ptr = malloc i32
6201 store i32 4, %ptr
6202
6203%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6204%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6205 <i>; yields {i32}:result1 = 4</i>
6206%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6207%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6208
6209%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6210%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6211 <i>; yields {i32}:result2 = 8</i>
6212
6213%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6214%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6215</pre>
6216</div>
6217
6218<!-- _______________________________________________________________________ -->
6219<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6220 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6221
6222</div>
6223<div class="doc_text">
6224<h5>Syntax:</h5>
6225<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6226 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]6227 integer bit width. Not all targets support all bit widths however.</p>
6228<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6229declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6230declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6231declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6232declare 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]6233
6234</pre>
6235<h5>Overview:</h5>
6236<p>
6237 This intrinsic adds <tt>delta</tt> to the value stored in memory at
6238 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6239</p>
6240<h5>Arguments:</h5>
6241<p>
6242
6243 The intrinsic takes two arguments, the first a pointer to an integer value
6244 and the second an integer value. The result is also an integer value. These
6245 integer types can have any bit width, but they must all have the same bit
6246 width. The targets may only lower integer representations they support.
6247</p>
6248<h5>Semantics:</h5>
6249<p>
6250 This intrinsic does a series of operations atomically. It first loads the
6251 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6252 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6253</p>
6254
6255<h5>Examples:</h5>
6256<pre>
6257%ptr = malloc i32
6258 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6259%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6260 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6261%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6262 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6263%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6264 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6265%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6266</pre>
6267</div>
6268
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6269<!-- _______________________________________________________________________ -->
6270<div class="doc_subsubsection">
6271 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6272
6273</div>
6274<div class="doc_text">
6275<h5>Syntax:</h5>
6276<p>
6277 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]6278 any integer bit width and for different address spaces. Not all targets
6279 support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6280<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6281declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6282declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6283declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6284declare 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]6285
6286</pre>
6287<h5>Overview:</h5>
6288<p>
6289 This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6290 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6291</p>
6292<h5>Arguments:</h5>
6293<p>
6294
6295 The intrinsic takes two arguments, the first a pointer to an integer value
6296 and the second an integer value. The result is also an integer value. These
6297 integer types can have any bit width, but they must all have the same bit
6298 width. The targets may only lower integer representations they support.
6299</p>
6300<h5>Semantics:</h5>
6301<p>
6302 This intrinsic does a series of operations atomically. It first loads the
6303 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6304 result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6305</p>
6306
6307<h5>Examples:</h5>
6308<pre>
6309%ptr = malloc i32
6310 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6311%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6312 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6313%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6314 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6315%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6316 <i>; yields {i32}:result3 = 2</i>
6317%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6318</pre>
6319</div>
6320
6321<!-- _______________________________________________________________________ -->
6322<div class="doc_subsubsection">
6323 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6324 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6325 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6326 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
6327
6328</div>
6329<div class="doc_text">
6330<h5>Syntax:</h5>
6331<p>
6332 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
6333 <tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6334 <tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
6335 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6336<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6337declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6338declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6339declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6340declare 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]6341
6342</pre>
6343
6344<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6345declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6346declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6347declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6348declare 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]6349
6350</pre>
6351
6352<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6353declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6354declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6355declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6356declare 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]6357
6358</pre>
6359
6360<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6361declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6362declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6363declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6364declare 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]6365
6366</pre>
6367<h5>Overview:</h5>
6368<p>
6369 These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6370 the value stored in memory at <tt>ptr</tt>. It yields the original value
6371 at <tt>ptr</tt>.
6372</p>
6373<h5>Arguments:</h5>
6374<p>
6375
6376 These intrinsics take two arguments, the first a pointer to an integer value
6377 and the second an integer value. The result is also an integer value. These
6378 integer types can have any bit width, but they must all have the same bit
6379 width. The targets may only lower integer representations they support.
6380</p>
6381<h5>Semantics:</h5>
6382<p>
6383 These intrinsics does a series of operations atomically. They first load the
6384 value stored at <tt>ptr</tt>. They then do the bitwise operation
6385 <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
6386 value stored at <tt>ptr</tt>.
6387</p>
6388
6389<h5>Examples:</h5>
6390<pre>
6391%ptr = malloc i32
6392 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6393%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6394 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6395%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6396 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6397%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6398 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6399%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6400 <i>; yields {i32}:result3 = FF</i>
6401%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6402</pre>
6403</div>
6404
6405
6406<!-- _______________________________________________________________________ -->
6407<div class="doc_subsubsection">
6408 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6409 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6410 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6411 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
6412
6413</div>
6414<div class="doc_text">
6415<h5>Syntax:</h5>
6416<p>
6417 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6418 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6419 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6420 address spaces. Not all targets
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6421 support all bit widths however.</p>
6422<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6423declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6424declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6425declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6426declare 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]6427
6428</pre>
6429
6430<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6431declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6432declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6433declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6434declare 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]6435
6436</pre>
6437
6438<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6439declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6440declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6441declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6442declare 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]6443
6444</pre>
6445
6446<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6447declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6448declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6449declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6450declare 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]6451
6452</pre>
6453<h5>Overview:</h5>
6454<p>
6455 These intrinsics takes the signed or unsigned minimum or maximum of
6456 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6457 original value at <tt>ptr</tt>.
6458</p>
6459<h5>Arguments:</h5>
6460<p>
6461
6462 These intrinsics take two arguments, the first a pointer to an integer value
6463 and the second an integer value. The result is also an integer value. These
6464 integer types can have any bit width, but they must all have the same bit
6465 width. The targets may only lower integer representations they support.
6466</p>
6467<h5>Semantics:</h5>
6468<p>
6469 These intrinsics does a series of operations atomically. They first load the
6470 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
6471 <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
6472 the original value stored at <tt>ptr</tt>.
6473</p>
6474
6475<h5>Examples:</h5>
6476<pre>
6477%ptr = malloc i32
6478 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6479%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6480 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6481%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6482 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6483%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6484 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6485%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6486 <i>; yields {i32}:result3 = 8</i>
6487%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6488</pre>
6489</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6490
6491<!-- ======================================================================= -->
6492<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6493 <a name="int_general">General Intrinsics</a>
6494</div>
6495
6496<div class="doc_text">
6497<p> This class of intrinsics is designed to be generic and has
6498no specific purpose. </p>
6499</div>
6500
6501<!-- _______________________________________________________________________ -->
6502<div class="doc_subsubsection">
6503 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6504</div>
6505
6506<div class="doc_text">
6507
6508<h5>Syntax:</h5>
6509<pre>
6510 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6511</pre>
6512
6513<h5>Overview:</h5>
6514
6515<p>
6516The '<tt>llvm.var.annotation</tt>' intrinsic
6517</p>
6518
6519<h5>Arguments:</h5>
6520
6521<p>
6522The first argument is a pointer to a value, the second is a pointer to a
6523global string, the third is a pointer to a global string which is the source
6524file name, and the last argument is the line number.
6525</p>
6526
6527<h5>Semantics:</h5>
6528
6529<p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6530This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6531This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6532annotations. These have no other defined use, they are ignored by code
6533generation and optimization.
6534</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6535</div>
6536
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6537<!-- _______________________________________________________________________ -->
6538<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]6539 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6540</div>
6541
6542<div class="doc_text">
6543
6544<h5>Syntax:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6545<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6546any integer bit width.
6547</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6548<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]6549 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6550 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6551 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6552 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6553 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]6554</pre>
6555
6556<h5>Overview:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6557
6558<p>
6559The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6560</p>
6561
6562<h5>Arguments:</h5>
6563
6564<p>
6565The first argument is an integer value (result of some expression),
6566the second is a pointer to a global string, the third is a pointer to a global
6567string which is the source file name, and the last argument is the line number.
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6568It returns the value of the first argument.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6569</p>
6570
6571<h5>Semantics:</h5>
6572
6573<p>
6574This intrinsic allows annotations to be put on arbitrary expressions
6575with arbitrary strings. This can be useful for special purpose optimizations
6576that want to look for these annotations. These have no other defined use, they
6577are ignored by code generation and optimization.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6578</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6579</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6580
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6581<!-- _______________________________________________________________________ -->
6582<div class="doc_subsubsection">
6583 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6584</div>
6585
6586<div class="doc_text">
6587
6588<h5>Syntax:</h5>
6589<pre>
6590 declare void @llvm.trap()
6591</pre>
6592
6593<h5>Overview:</h5>
6594
6595<p>
6596The '<tt>llvm.trap</tt>' intrinsic
6597</p>
6598
6599<h5>Arguments:</h5>
6600
6601<p>
6602None
6603</p>
6604
6605<h5>Semantics:</h5>
6606
6607<p>
6608This intrinsics is lowered to the target dependent trap instruction. If the
6609target does not have a trap instruction, this intrinsic will be lowered to the
6610call of the abort() function.
6611</p>
6612</div>
6613
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6614<!-- _______________________________________________________________________ -->
6615<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]6616 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6617</div>
6618<div class="doc_text">
6619<h5>Syntax:</h5>
6620<pre>
6621declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
6622
6623</pre>
6624<h5>Overview:</h5>
6625<p>
6626 The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and stores
6627 it onto the stack at <tt>slot</tt>. The stack slot is adjusted to ensure that
6628 it is placed on the stack before local variables.
6629</p>
6630<h5>Arguments:</h5>
6631<p>
6632 The <tt>llvm.stackprotector</tt> intrinsic requires two pointer arguments. The
6633 first argument is the value loaded from the stack guard
6634 <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt> that
6635 has enough space to hold the value of the guard.
6636</p>
6637<h5>Semantics:</h5>
6638<p>
6639 This intrinsic causes the prologue/epilogue inserter to force the position of
6640 the <tt>AllocaInst</tt> stack slot to be before local variables on the
6641 stack. This is to ensure that if a local variable on the stack is overwritten,
6642 it will destroy the value of the guard. When the function exits, the guard on
6643 the stack is checked against the original guard. If they're different, then
6644 the program aborts by calling the <tt>__stack_chk_fail()</tt> function.
6645</p>
6646</div>
6647
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6648<!-- *********************************************************************** -->
6649<hr>
6650<address>
6651 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]6652 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6653 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]6654 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6655
6656 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
6657 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
6658 Last modified: $Date$
6659</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]6660
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6661</body>
6662</html>