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4<head>
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>
58 </ol>
59 </li>
60 <li><a href="#constants">Constants</a>
61 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]62 <li><a href="#simpleconstants">Simple Constants</a></li>
63 <li><a href="#aggregateconstants">Aggregate Constants</a></li>
64 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
65 <li><a href="#undefvalues">Undefined Values</a></li>
66 <li><a href="#constantexprs">Constant Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]67 </ol>
68 </li>
69 <li><a href="#othervalues">Other Values</a>
70 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]71 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]72 </ol>
73 </li>
74 <li><a href="#instref">Instruction Reference</a>
75 <ol>
76 <li><a href="#terminators">Terminator Instructions</a>
77 <ol>
78 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
79 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
80 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
81 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
82 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
83 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
84 </ol>
85 </li>
86 <li><a href="#binaryops">Binary Operations</a>
87 <ol>
88 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
89 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
90 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
91 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
92 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
93 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
94 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
95 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
96 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
97 </ol>
98 </li>
99 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
100 <ol>
101 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
102 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
103 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
104 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
105 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
106 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
107 </ol>
108 </li>
109 <li><a href="#vectorops">Vector Operations</a>
110 <ol>
111 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
112 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
113 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
114 </ol>
115 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]116 <li><a href="#aggregateops">Aggregate Operations</a>
117 <ol>
118 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
119 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
120 </ol>
121 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]122 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
123 <ol>
124 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
125 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
126 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
127 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
128 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
129 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
130 </ol>
131 </li>
132 <li><a href="#convertops">Conversion Operations</a>
133 <ol>
134 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
135 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
136 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
137 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
138 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
139 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
140 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
141 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
142 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
143 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
144 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
145 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
146 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]147 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]148 <li><a href="#otherops">Other Operations</a>
149 <ol>
150 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
151 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]152 <li><a href="#i_vicmp">'<tt>vicmp</tt>' Instruction</a></li>
153 <li><a href="#i_vfcmp">'<tt>vfcmp</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]154 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
155 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
156 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
157 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
158 </ol>
159 </li>
160 </ol>
161 </li>
162 <li><a href="#intrinsics">Intrinsic Functions</a>
163 <ol>
164 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
165 <ol>
166 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
167 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
168 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
169 </ol>
170 </li>
171 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
172 <ol>
173 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
174 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
175 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
176 </ol>
177 </li>
178 <li><a href="#int_codegen">Code Generator Intrinsics</a>
179 <ol>
180 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
181 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
182 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
183 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
184 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
185 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
186 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
187 </ol>
188 </li>
189 <li><a href="#int_libc">Standard C Library Intrinsics</a>
190 <ol>
191 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
192 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
193 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
194 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
195 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]196 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
197 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
198 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]199 </ol>
200 </li>
201 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
202 <ol>
203 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
204 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
205 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
206 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
207 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
208 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
209 </ol>
210 </li>
211 <li><a href="#int_debugger">Debugger intrinsics</a></li>
212 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]213 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]214 <ol>
215 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]216 </ol>
217 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]218 <li><a href="#int_atomics">Atomic intrinsics</a>
219 <ol>
220 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
221 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
222 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
223 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
224 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
225 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
226 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
227 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
228 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
229 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
230 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
231 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
232 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
233 </ol>
234 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]235 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]236 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]237 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]238 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]239 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]240 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]241 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]242 '<tt>llvm.trap</tt>' Intrinsic</a></li>
243 <li><a href="#int_stackprotector">
244 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]245 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]246 </li>
247 </ol>
248 </li>
249</ol>
250
251<div class="doc_author">
252 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
253 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
254</div>
255
256<!-- *********************************************************************** -->
257<div class="doc_section"> <a name="abstract">Abstract </a></div>
258<!-- *********************************************************************** -->
259
260<div class="doc_text">
261<p>This document is a reference manual for the LLVM assembly language.
Bill Wendlinge7846a52008-08-05 22:29:16 +0000[diff] [blame]262LLVM is a Static Single Assignment (SSA) based representation that provides
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]263type safety, low-level operations, flexibility, and the capability of
264representing 'all' high-level languages cleanly. It is the common code
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]265representation used throughout all phases of the LLVM compilation
266strategy.</p>
267</div>
268
269<!-- *********************************************************************** -->
270<div class="doc_section"> <a name="introduction">Introduction</a> </div>
271<!-- *********************************************************************** -->
272
273<div class="doc_text">
274
275<p>The LLVM code representation is designed to be used in three
276different forms: as an in-memory compiler IR, as an on-disk bitcode
277representation (suitable for fast loading by a Just-In-Time compiler),
278and as a human readable assembly language representation. This allows
279LLVM to provide a powerful intermediate representation for efficient
280compiler transformations and analysis, while providing a natural means
281to debug and visualize the transformations. The three different forms
282of LLVM are all equivalent. This document describes the human readable
283representation and notation.</p>
284
285<p>The LLVM representation aims to be light-weight and low-level
286while being expressive, typed, and extensible at the same time. It
287aims to be a "universal IR" of sorts, by being at a low enough level
288that high-level ideas may be cleanly mapped to it (similar to how
289microprocessors are "universal IR's", allowing many source languages to
290be mapped to them). By providing type information, LLVM can be used as
291the target of optimizations: for example, through pointer analysis, it
292can be proven that a C automatic variable is never accessed outside of
293the current function... allowing it to be promoted to a simple SSA
294value instead of a memory location.</p>
295
296</div>
297
298<!-- _______________________________________________________________________ -->
299<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
300
301<div class="doc_text">
302
303<p>It is important to note that this document describes 'well formed'
304LLVM assembly language. There is a difference between what the parser
305accepts and what is considered 'well formed'. For example, the
306following instruction is syntactically okay, but not well formed:</p>
307
308<div class="doc_code">
309<pre>
310%x = <a href="#i_add">add</a> i32 1, %x
311</pre>
312</div>
313
314<p>...because the definition of <tt>%x</tt> does not dominate all of
315its uses. The LLVM infrastructure provides a verification pass that may
316be used to verify that an LLVM module is well formed. This pass is
317automatically run by the parser after parsing input assembly and by
318the optimizer before it outputs bitcode. The violations pointed out
319by the verifier pass indicate bugs in transformation passes or input to
320the parser.</p>
321</div>
322
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]323<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]324
325<!-- *********************************************************************** -->
326<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
327<!-- *********************************************************************** -->
328
329<div class="doc_text">
330
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]331 <p>LLVM identifiers come in two basic types: global and local. Global
332 identifiers (functions, global variables) begin with the @ character. Local
333 identifiers (register names, types) begin with the % character. Additionally,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]334 there are three different formats for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]335
336<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]337 <li>Named values are represented as a string of characters with their prefix.
338 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
339 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]340 Identifiers which require other characters in their names can be surrounded
Daniel Dunbar73f9a772008-10-14 23:51:43 +0000[diff] [blame]341 with quotes. Special characters may be escaped using "\xx" where xx is the
342 ASCII code for the character in hexadecimal. In this way, any character can
343 be used in a name value, even quotes themselves.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]344
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]345 <li>Unnamed values are represented as an unsigned numeric value with their
346 prefix. For example, %12, @2, %44.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]347
348 <li>Constants, which are described in a <a href="#constants">section about
349 constants</a>, below.</li>
350</ol>
351
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]352<p>LLVM requires that values start with a prefix for two reasons: Compilers
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]353don't need to worry about name clashes with reserved words, and the set of
354reserved words may be expanded in the future without penalty. Additionally,
355unnamed identifiers allow a compiler to quickly come up with a temporary
356variable without having to avoid symbol table conflicts.</p>
357
358<p>Reserved words in LLVM are very similar to reserved words in other
359languages. There are keywords for different opcodes
360('<tt><a href="#i_add">add</a></tt>',
361 '<tt><a href="#i_bitcast">bitcast</a></tt>',
362 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
363href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
364and others. These reserved words cannot conflict with variable names, because
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]365none of them start with a prefix character ('%' or '@').</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]366
367<p>Here is an example of LLVM code to multiply the integer variable
368'<tt>%X</tt>' by 8:</p>
369
370<p>The easy way:</p>
371
372<div class="doc_code">
373<pre>
374%result = <a href="#i_mul">mul</a> i32 %X, 8
375</pre>
376</div>
377
378<p>After strength reduction:</p>
379
380<div class="doc_code">
381<pre>
382%result = <a href="#i_shl">shl</a> i32 %X, i8 3
383</pre>
384</div>
385
386<p>And the hard way:</p>
387
388<div class="doc_code">
389<pre>
390<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
391<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
392%result = <a href="#i_add">add</a> i32 %1, %1
393</pre>
394</div>
395
396<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
397important lexical features of LLVM:</p>
398
399<ol>
400
401 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
402 line.</li>
403
404 <li>Unnamed temporaries are created when the result of a computation is not
405 assigned to a named value.</li>
406
407 <li>Unnamed temporaries are numbered sequentially</li>
408
409</ol>
410
411<p>...and it also shows a convention that we follow in this document. When
412demonstrating instructions, we will follow an instruction with a comment that
413defines the type and name of value produced. Comments are shown in italic
414text.</p>
415
416</div>
417
418<!-- *********************************************************************** -->
419<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
420<!-- *********************************************************************** -->
421
422<!-- ======================================================================= -->
423<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
424</div>
425
426<div class="doc_text">
427
428<p>LLVM programs are composed of "Module"s, each of which is a
429translation unit of the input programs. Each module consists of
430functions, global variables, and symbol table entries. Modules may be
431combined together with the LLVM linker, which merges function (and
432global variable) definitions, resolves forward declarations, and merges
433symbol table entries. Here is an example of the "hello world" module:</p>
434
435<div class="doc_code">
436<pre><i>; Declare the string constant as a global constant...</i>
437<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
438 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
439
440<i>; External declaration of the puts function</i>
441<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
442
443<i>; Definition of main function</i>
444define i32 @main() { <i>; i32()* </i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]445 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]446 %cast210 = <a
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]447 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]448
449 <i>; Call puts function to write out the string to stdout...</i>
450 <a
451 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
452 <a
453 href="#i_ret">ret</a> i32 0<br>}<br>
454</pre>
455</div>
456
457<p>This example is made up of a <a href="#globalvars">global variable</a>
458named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
459function, and a <a href="#functionstructure">function definition</a>
460for "<tt>main</tt>".</p>
461
462<p>In general, a module is made up of a list of global values,
463where both functions and global variables are global values. Global values are
464represented by a pointer to a memory location (in this case, a pointer to an
465array of char, and a pointer to a function), and have one of the following <a
466href="#linkage">linkage types</a>.</p>
467
468</div>
469
470<!-- ======================================================================= -->
471<div class="doc_subsection">
472 <a name="linkage">Linkage Types</a>
473</div>
474
475<div class="doc_text">
476
477<p>
478All Global Variables and Functions have one of the following types of linkage:
479</p>
480
481<dl>
482
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]483 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]484
485 <dd>Global values with internal linkage are only directly accessible by
486 objects in the current module. In particular, linking code into a module with
487 an internal global value may cause the internal to be renamed as necessary to
488 avoid collisions. Because the symbol is internal to the module, all
489 references can be updated. This corresponds to the notion of the
490 '<tt>static</tt>' keyword in C.
491 </dd>
492
493 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
494
495 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
496 the same name when linkage occurs. This is typically used to implement
497 inline functions, templates, or other code which must be generated in each
498 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
499 allowed to be discarded.
500 </dd>
501
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]502 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
503
504 <dd>"<tt>common</tt>" linkage is exactly the same as <tt>linkonce</tt>
505 linkage, except that unreferenced <tt>common</tt> globals may not be
506 discarded. This is used for globals that may be emitted in multiple
507 translation units, but that are not guaranteed to be emitted into every
508 translation unit that uses them. One example of this is tentative
509 definitions in C, such as "<tt>int X;</tt>" at global scope.
510 </dd>
511
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]512 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
513
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]514 <dd>"<tt>weak</tt>" linkage is the same as <tt>common</tt> linkage, except
515 that some targets may choose to emit different assembly sequences for them
516 for target-dependent reasons. This is used for globals that are declared
517 "weak" in C source code.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]518 </dd>
519
520 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
521
522 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
523 pointer to array type. When two global variables with appending linkage are
524 linked together, the two global arrays are appended together. This is the
525 LLVM, typesafe, equivalent of having the system linker append together
526 "sections" with identical names when .o files are linked.
527 </dd>
528
529 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]530 <dd>The semantics of this linkage follow the ELF object file model: the
531 symbol is weak until linked, if not linked, the symbol becomes null instead
532 of being an undefined reference.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]533 </dd>
534
535 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
536
537 <dd>If none of the above identifiers are used, the global is externally
538 visible, meaning that it participates in linkage and can be used to resolve
539 external symbol references.
540 </dd>
541</dl>
542
543 <p>
544 The next two types of linkage are targeted for Microsoft Windows platform
545 only. They are designed to support importing (exporting) symbols from (to)
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]546 DLLs (Dynamic Link Libraries).
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]547 </p>
548
549 <dl>
550 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
551
552 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
553 or variable via a global pointer to a pointer that is set up by the DLL
554 exporting the symbol. On Microsoft Windows targets, the pointer name is
555 formed by combining <code>_imp__</code> and the function or variable name.
556 </dd>
557
558 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
559
560 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
561 pointer to a pointer in a DLL, so that it can be referenced with the
562 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
563 name is formed by combining <code>_imp__</code> and the function or variable
564 name.
565 </dd>
566
567</dl>
568
Dan Gohman4dfac702008-11-24 17:18:39 +0000[diff] [blame]569<p>For example, since the "<tt>.LC0</tt>"
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]570variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
571variable and was linked with this one, one of the two would be renamed,
572preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
573external (i.e., lacking any linkage declarations), they are accessible
574outside of the current module.</p>
575<p>It is illegal for a function <i>declaration</i>
576to have any linkage type other than "externally visible", <tt>dllimport</tt>,
577or <tt>extern_weak</tt>.</p>
578<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]579linkages.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]580</div>
581
582<!-- ======================================================================= -->
583<div class="doc_subsection">
584 <a name="callingconv">Calling Conventions</a>
585</div>
586
587<div class="doc_text">
588
589<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
590and <a href="#i_invoke">invokes</a> can all have an optional calling convention
591specified for the call. The calling convention of any pair of dynamic
592caller/callee must match, or the behavior of the program is undefined. The
593following calling conventions are supported by LLVM, and more may be added in
594the future:</p>
595
596<dl>
597 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
598
599 <dd>This calling convention (the default if no other calling convention is
600 specified) matches the target C calling conventions. This calling convention
601 supports varargs function calls and tolerates some mismatch in the declared
602 prototype and implemented declaration of the function (as does normal C).
603 </dd>
604
605 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
606
607 <dd>This calling convention attempts to make calls as fast as possible
608 (e.g. by passing things in registers). This calling convention allows the
609 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]610 without having to conform to an externally specified ABI (Application Binary
611 Interface). Implementations of this convention should allow arbitrary
Arnold Schwaighofer07444922008-05-14 09:17:12 +0000[diff] [blame]612 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> to be
613 supported. This calling convention does not support varargs and requires the
614 prototype of all callees to exactly match the prototype of the function
615 definition.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]616 </dd>
617
618 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
619
620 <dd>This calling convention attempts to make code in the caller as efficient
621 as possible under the assumption that the call is not commonly executed. As
622 such, these calls often preserve all registers so that the call does not break
623 any live ranges in the caller side. This calling convention does not support
624 varargs and requires the prototype of all callees to exactly match the
625 prototype of the function definition.
626 </dd>
627
628 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
629
630 <dd>Any calling convention may be specified by number, allowing
631 target-specific calling conventions to be used. Target specific calling
632 conventions start at 64.
633 </dd>
634</dl>
635
636<p>More calling conventions can be added/defined on an as-needed basis, to
637support pascal conventions or any other well-known target-independent
638convention.</p>
639
640</div>
641
642<!-- ======================================================================= -->
643<div class="doc_subsection">
644 <a name="visibility">Visibility Styles</a>
645</div>
646
647<div class="doc_text">
648
649<p>
650All Global Variables and Functions have one of the following visibility styles:
651</p>
652
653<dl>
654 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
655
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]656 <dd>On targets that use the ELF object file format, default visibility means
657 that the declaration is visible to other
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]658 modules and, in shared libraries, means that the declared entity may be
659 overridden. On Darwin, default visibility means that the declaration is
660 visible to other modules. Default visibility corresponds to "external
661 linkage" in the language.
662 </dd>
663
664 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
665
666 <dd>Two declarations of an object with hidden visibility refer to the same
667 object if they are in the same shared object. Usually, hidden visibility
668 indicates that the symbol will not be placed into the dynamic symbol table,
669 so no other module (executable or shared library) can reference it
670 directly.
671 </dd>
672
673 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
674
675 <dd>On ELF, protected visibility indicates that the symbol will be placed in
676 the dynamic symbol table, but that references within the defining module will
677 bind to the local symbol. That is, the symbol cannot be overridden by another
678 module.
679 </dd>
680</dl>
681
682</div>
683
684<!-- ======================================================================= -->
685<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame^]686 <a name="namedtypes">Named Types</a>
687</div>
688
689<div class="doc_text">
690
691<p>LLVM IR allows you to specify name aliases for certain types. This can make
692it easier to read the IR and make the IR more condensed (particularly when
693recursive types are involved). An example of a name specification is:
694</p>
695
696<div class="doc_code">
697<pre>
698%mytype = type { %mytype*, i32 }
699</pre>
700</div>
701
702<p>You may give a name to any <a href="#typesystem">type</a> except "<a
703href="t_void">void</a>". Type name aliases may be used anywhere a type is
704expected with the syntax "%mytype".</p>
705
706<p>Note that type names are aliases for the structural type that they indicate,
707and that you can therefore specify multiple names for the same type. This often
708leads to confusing behavior when dumping out a .ll file. Since LLVM IR uses
709structural typing, the name is not part of the type. When printing out LLVM IR,
710the printer will pick <em>one name</em> to render all types of a particular
711shape. This means that if you have code where two different source types end up
712having the same LLVM type, that the dumper will sometimes print the "wrong" or
713unexpected type. This is an important design point and isn't going to
714change.</p>
715
716</div>
717
718
719<!-- ======================================================================= -->
720<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]721 <a name="globalvars">Global Variables</a>
722</div>
723
724<div class="doc_text">
725
726<p>Global variables define regions of memory allocated at compilation time
727instead of run-time. Global variables may optionally be initialized, may have
728an explicit section to be placed in, and may have an optional explicit alignment
729specified. A variable may be defined as "thread_local", which means that it
730will not be shared by threads (each thread will have a separated copy of the
731variable). A variable may be defined as a global "constant," which indicates
732that the contents of the variable will <b>never</b> be modified (enabling better
733optimization, allowing the global data to be placed in the read-only section of
734an executable, etc). Note that variables that need runtime initialization
735cannot be marked "constant" as there is a store to the variable.</p>
736
737<p>
738LLVM explicitly allows <em>declarations</em> of global variables to be marked
739constant, even if the final definition of the global is not. This capability
740can be used to enable slightly better optimization of the program, but requires
741the language definition to guarantee that optimizations based on the
742'constantness' are valid for the translation units that do not include the
743definition.
744</p>
745
746<p>As SSA values, global variables define pointer values that are in
747scope (i.e. they dominate) all basic blocks in the program. Global
748variables always define a pointer to their "content" type because they
749describe a region of memory, and all memory objects in LLVM are
750accessed through pointers.</p>
751
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]752<p>A global variable may be declared to reside in a target-specifc numbered
753address space. For targets that support them, address spaces may affect how
754optimizations are performed and/or what target instructions are used to access
Christopher Lamb20a39e92007-12-12 08:44:39 +0000[diff] [blame]755the variable. The default address space is zero. The address space qualifier
756must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]757
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]758<p>LLVM allows an explicit section to be specified for globals. If the target
759supports it, it will emit globals to the section specified.</p>
760
761<p>An explicit alignment may be specified for a global. If not present, or if
762the alignment is set to zero, the alignment of the global is set by the target
763to whatever it feels convenient. If an explicit alignment is specified, the
764global is forced to have at least that much alignment. All alignments must be
765a power of 2.</p>
766
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]767<p>For example, the following defines a global in a numbered address space with
768an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]769
770<div class="doc_code">
771<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]772@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]773</pre>
774</div>
775
776</div>
777
778
779<!-- ======================================================================= -->
780<div class="doc_subsection">
781 <a name="functionstructure">Functions</a>
782</div>
783
784<div class="doc_text">
785
786<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
787an optional <a href="#linkage">linkage type</a>, an optional
788<a href="#visibility">visibility style</a>, an optional
789<a href="#callingconv">calling convention</a>, a return type, an optional
790<a href="#paramattrs">parameter attribute</a> for the return type, a function
791name, a (possibly empty) argument list (each with optional
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]792<a href="#paramattrs">parameter attributes</a>), optional
793<a href="#fnattrs">function attributes</a>, an optional section,
794an optional alignment, an optional <a href="#gc">garbage collector name</a>,
Chris Lattneree202542008-10-04 18:10:21 +0000[diff] [blame]795an opening curly brace, a list of basic blocks, and a closing curly brace.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]796
797LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
798optional <a href="#linkage">linkage type</a>, an optional
799<a href="#visibility">visibility style</a>, an optional
800<a href="#callingconv">calling convention</a>, a return type, an optional
801<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]802name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksend606f5b2007-12-10 03:30:21 +0000[diff] [blame]803<a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]804
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]805<p>A function definition contains a list of basic blocks, forming the CFG
806(Control Flow Graph) for
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]807the function. Each basic block may optionally start with a label (giving the
808basic block a symbol table entry), contains a list of instructions, and ends
809with a <a href="#terminators">terminator</a> instruction (such as a branch or
810function return).</p>
811
812<p>The first basic block in a function is special in two ways: it is immediately
813executed on entrance to the function, and it is not allowed to have predecessor
814basic blocks (i.e. there can not be any branches to the entry block of a
815function). Because the block can have no predecessors, it also cannot have any
816<a href="#i_phi">PHI nodes</a>.</p>
817
818<p>LLVM allows an explicit section to be specified for functions. If the target
819supports it, it will emit functions to the section specified.</p>
820
821<p>An explicit alignment may be specified for a function. If not present, or if
822the alignment is set to zero, the alignment of the function is set by the target
823to whatever it feels convenient. If an explicit alignment is specified, the
824function is forced to have at least that much alignment. All alignments must be
825a power of 2.</p>
826
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]827 <h5>Syntax:</h5>
828
829<div class="doc_code">
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]830<tt>
831define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
832 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
833 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
834 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
835 [<a href="#gc">gc</a>] { ... }
836</tt>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]837</div>
838
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]839</div>
840
841
842<!-- ======================================================================= -->
843<div class="doc_subsection">
844 <a name="aliasstructure">Aliases</a>
845</div>
846<div class="doc_text">
847 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikov96822812008-03-22 08:36:14 +0000[diff] [blame]848 function, global variable, another alias or bitcast of global value). Aliases
849 may have an optional <a href="#linkage">linkage type</a>, and an
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]850 optional <a href="#visibility">visibility style</a>.</p>
851
852 <h5>Syntax:</h5>
853
854<div class="doc_code">
855<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]856@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]857</pre>
858</div>
859
860</div>
861
862
863
864<!-- ======================================================================= -->
865<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
866<div class="doc_text">
867 <p>The return type and each parameter of a function type may have a set of
868 <i>parameter attributes</i> associated with them. Parameter attributes are
869 used to communicate additional information about the result or parameters of
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]870 a function. Parameter attributes are considered to be part of the function,
871 not of the function type, so functions with different parameter attributes
872 can have the same function type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]873
874 <p>Parameter attributes are simple keywords that follow the type specified. If
875 multiple parameter attributes are needed, they are space separated. For
876 example:</p>
877
878<div class="doc_code">
879<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]880declare i32 @printf(i8* noalias , ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]881declare i32 @atoi(i8 zeroext)
882declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]883</pre>
884</div>
885
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]886 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
887 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]888
889 <p>Currently, only the following parameter attributes are defined:</p>
890 <dl>
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]891 <dt><tt>zeroext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]892 <dd>This indicates to the code generator that the parameter or return value
893 should be zero-extended to a 32-bit value by the caller (for a parameter)
894 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]895
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]896 <dt><tt>signext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]897 <dd>This indicates to the code generator that the parameter or return value
898 should be sign-extended to a 32-bit value by the caller (for a parameter)
899 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]900
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]901 <dt><tt>inreg</tt></dt>
Dale Johannesenc08a0e22008-09-25 20:47:45 +0000[diff] [blame]902 <dd>This indicates that this parameter or return value should be treated
903 in a special target-dependent fashion during while emitting code for a
904 function call or return (usually, by putting it in a register as opposed
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]905 to memory, though some targets use it to distinguish between two different
906 kinds of registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]907
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]908 <dt><tt><a name="byval">byval</a></tt></dt>
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]909 <dd>This indicates that the pointer parameter should really be passed by
910 value to the function. The attribute implies that a hidden copy of the
911 pointee is made between the caller and the callee, so the callee is unable
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]912 to modify the value in the callee. This attribute is only valid on LLVM
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]913 pointer arguments. It is generally used to pass structs and arrays by
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]914 value, but is also valid on pointers to scalars. The copy is considered to
915 belong to the caller not the callee (for example,
916 <tt><a href="#readonly">readonly</a></tt> functions should not write to
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]917 <tt>byval</tt> parameters). This is not a valid attribute for return
918 values. </dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]919
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]920 <dt><tt>sret</tt></dt>
Duncan Sands616cc032008-02-18 04:19:38 +0000[diff] [blame]921 <dd>This indicates that the pointer parameter specifies the address of a
922 structure that is the return value of the function in the source program.
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]923 This pointer must be guaranteed by the caller to be valid: loads and stores
924 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]925 be applied to the first parameter. This is not a valid attribute for
926 return values. </dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]927
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]928 <dt><tt>noalias</tt></dt>
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]929 <dd>This indicates that the pointer does not alias any global or any other
930 parameter. The caller is responsible for ensuring that this is the
Nick Lewyckya604a942008-11-24 05:00:44 +0000[diff] [blame]931 case. On a function return value, <tt>noalias</tt> additionally indicates
932 that the pointer does not alias any other pointers visible to the
Nick Lewycky40fb6f22008-12-19 06:39:12 +0000[diff] [blame]933 caller. For further details, please see the discussion of the NoAlias
934 response in
935 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
936 analysis</a>.</dd>
937
938 <dt><tt>nocapture</tt></dt>
939 <dd>This indicates that the callee does not make any copies of the pointer
940 that outlive the callee itself. This is not a valid attribute for return
941 values.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]942
Duncan Sands4ee46812007-07-27 19:57:41 +0000[diff] [blame]943 <dt><tt>nest</tt></dt>
Duncan Sandsf1a7d4c2008-07-08 09:27:25 +0000[diff] [blame]944 <dd>This indicates that the pointer parameter can be excised using the
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]945 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
946 attribute for return values.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]947 </dl>
948
949</div>
950
951<!-- ======================================================================= -->
952<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]953 <a name="gc">Garbage Collector Names</a>
954</div>
955
956<div class="doc_text">
957<p>Each function may specify a garbage collector name, which is simply a
958string.</p>
959
960<div class="doc_code"><pre
961>define void @f() gc "name" { ...</pre></div>
962
963<p>The compiler declares the supported values of <i>name</i>. Specifying a
964collector which will cause the compiler to alter its output in order to support
965the named garbage collection algorithm.</p>
966</div>
967
968<!-- ======================================================================= -->
969<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]970 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]971</div>
972
973<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]974
975<p>Function attributes are set to communicate additional information about
976 a function. Function attributes are considered to be part of the function,
977 not of the function type, so functions with different parameter attributes
978 can have the same function type.</p>
979
980 <p>Function attributes are simple keywords that follow the type specified. If
981 multiple attributes are needed, they are space separated. For
982 example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]983
984<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]985<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]986define void @f() noinline { ... }
987define void @f() alwaysinline { ... }
988define void @f() alwaysinline optsize { ... }
989define void @f() optsize
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]990</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]991</div>
992
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]993<dl>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]994<dt><tt>alwaysinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]995<dd>This attribute indicates that the inliner should attempt to inline this
996function into callers whenever possible, ignoring any active inlining size
997threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]998
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]999<dt><tt>noinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1000<dd>This attribute indicates that the inliner should never inline this function
Chris Lattner377f3ae2008-10-05 17:14:59 +0000[diff] [blame]1001in any situation. This attribute may not be used together with the
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1002<tt>alwaysinline</tt> attribute.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1003
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1004<dt><tt>optsize</tt></dt>
Devang Patelc29099b2008-09-29 18:34:44 +0000[diff] [blame]1005<dd>This attribute suggests that optimization passes and code generator passes
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1006make choices that keep the code size of this function low, and otherwise do
1007optimizations specifically to reduce code size.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1008
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1009<dt><tt>noreturn</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1010<dd>This function attribute indicates that the function never returns normally.
1011This produces undefined behavior at runtime if the function ever does
1012dynamically return.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1013
1014<dt><tt>nounwind</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1015<dd>This function attribute indicates that the function never returns with an
1016unwind or exceptional control flow. If the function does unwind, its runtime
1017behavior is undefined.</dd>
1018
1019<dt><tt>readnone</tt></dt>
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]1020<dd>This attribute indicates that the function computes its result (or the
1021exception it throws) based strictly on its arguments, without dereferencing any
1022pointer arguments or otherwise accessing any mutable state (e.g. memory, control
1023registers, etc) visible to caller functions. It does not write through any
1024pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments) and
1025never changes any state visible to callers.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1026
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]1027<dt><tt><a name="readonly">readonly</a></tt></dt>
1028<dd>This attribute indicates that the function does not write through any
1029pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments)
1030or otherwise modify any state (e.g. memory, control registers, etc) visible to
1031caller functions. It may dereference pointer arguments and read state that may
1032be set in the caller. A readonly function always returns the same value (or
1033throws the same exception) when called with the same set of arguments and global
1034state.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1035
1036<dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1037<dd>This attribute indicates that the function should emit a stack smashing
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1038protector. It is in the form of a "canary"&mdash;a random value placed on the
1039stack before the local variables that's checked upon return from the function to
1040see if it has been overwritten. A heuristic is used to determine if a function
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1041needs stack protectors or not.
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1042
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1043<p>If a function that has an <tt>ssp</tt> attribute is inlined into a function
1044that doesn't have an <tt>ssp</tt> attribute, then the resulting function will
1045have an <tt>ssp</tt> attribute.</p></dd>
1046
1047<dt><tt>sspreq</tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1048<dd>This attribute indicates that the function should <em>always</em> emit a
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1049stack smashing protector. This overrides the <tt><a href="#ssp">ssp</a></tt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1050function attribute.
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1051
1052<p>If a function that has an <tt>sspreq</tt> attribute is inlined into a
1053function that doesn't have an <tt>sspreq</tt> attribute or which has
1054an <tt>ssp</tt> attribute, then the resulting function will have
1055an <tt>sspreq</tt> attribute.</p></dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1056</dl>
1057
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1058</div>
1059
1060<!-- ======================================================================= -->
1061<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1062 <a name="moduleasm">Module-Level Inline Assembly</a>
1063</div>
1064
1065<div class="doc_text">
1066<p>
1067Modules may contain "module-level inline asm" blocks, which corresponds to the
1068GCC "file scope inline asm" blocks. These blocks are internally concatenated by
1069LLVM and treated as a single unit, but may be separated in the .ll file if
1070desired. The syntax is very simple:
1071</p>
1072
1073<div class="doc_code">
1074<pre>
1075module asm "inline asm code goes here"
1076module asm "more can go here"
1077</pre>
1078</div>
1079
1080<p>The strings can contain any character by escaping non-printable characters.
1081 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
1082 for the number.
1083</p>
1084
1085<p>
1086 The inline asm code is simply printed to the machine code .s file when
1087 assembly code is generated.
1088</p>
1089</div>
1090
1091<!-- ======================================================================= -->
1092<div class="doc_subsection">
1093 <a name="datalayout">Data Layout</a>
1094</div>
1095
1096<div class="doc_text">
1097<p>A module may specify a target specific data layout string that specifies how
1098data is to be laid out in memory. The syntax for the data layout is simply:</p>
1099<pre> target datalayout = "<i>layout specification</i>"</pre>
1100<p>The <i>layout specification</i> consists of a list of specifications
1101separated by the minus sign character ('-'). Each specification starts with a
1102letter and may include other information after the letter to define some
1103aspect of the data layout. The specifications accepted are as follows: </p>
1104<dl>
1105 <dt><tt>E</tt></dt>
1106 <dd>Specifies that the target lays out data in big-endian form. That is, the
1107 bits with the most significance have the lowest address location.</dd>
1108 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1109 <dd>Specifies that the target lays out data in little-endian form. That is,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1110 the bits with the least significance have the lowest address location.</dd>
1111 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1112 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
1113 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
1114 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
1115 too.</dd>
1116 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1117 <dd>This specifies the alignment for an integer type of a given bit
1118 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1119 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1120 <dd>This specifies the alignment for a vector type of a given bit
1121 <i>size</i>.</dd>
1122 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1123 <dd>This specifies the alignment for a floating point type of a given bit
1124 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1125 (double).</dd>
1126 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1127 <dd>This specifies the alignment for an aggregate type of a given bit
1128 <i>size</i>.</dd>
1129</dl>
1130<p>When constructing the data layout for a given target, LLVM starts with a
1131default set of specifications which are then (possibly) overriden by the
1132specifications in the <tt>datalayout</tt> keyword. The default specifications
1133are given in this list:</p>
1134<ul>
1135 <li><tt>E</tt> - big endian</li>
1136 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1137 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1138 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1139 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1140 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1141 <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]1142 alignment of 64-bits</li>
1143 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1144 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1145 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1146 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1147 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
1148</ul>
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]1149<p>When LLVM is determining the alignment for a given type, it uses the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1150following rules:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1151<ol>
1152 <li>If the type sought is an exact match for one of the specifications, that
1153 specification is used.</li>
1154 <li>If no match is found, and the type sought is an integer type, then the
1155 smallest integer type that is larger than the bitwidth of the sought type is
1156 used. If none of the specifications are larger than the bitwidth then the the
1157 largest integer type is used. For example, given the default specifications
1158 above, the i7 type will use the alignment of i8 (next largest) while both
1159 i65 and i256 will use the alignment of i64 (largest specified).</li>
1160 <li>If no match is found, and the type sought is a vector type, then the
1161 largest vector type that is smaller than the sought vector type will be used
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1162 as a fall back. This happens because &lt;128 x double&gt; can be implemented
1163 in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1164</ol>
1165</div>
1166
1167<!-- *********************************************************************** -->
1168<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1169<!-- *********************************************************************** -->
1170
1171<div class="doc_text">
1172
1173<p>The LLVM type system is one of the most important features of the
1174intermediate representation. Being typed enables a number of
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1175optimizations to be performed on the intermediate representation directly,
1176without having to do
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1177extra analyses on the side before the transformation. A strong type
1178system makes it easier to read the generated code and enables novel
1179analyses and transformations that are not feasible to perform on normal
1180three address code representations.</p>
1181
1182</div>
1183
1184<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1185<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1186Classifications</a> </div>
1187<div class="doc_text">
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1188<p>The types fall into a few useful
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1189classifications:</p>
1190
1191<table border="1" cellspacing="0" cellpadding="4">
1192 <tbody>
1193 <tr><th>Classification</th><th>Types</th></tr>
1194 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1195 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1196 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1197 </tr>
1198 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1199 <td><a href="#t_floating">floating point</a></td>
1200 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1201 </tr>
1202 <tr>
1203 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1204 <td><a href="#t_integer">integer</a>,
1205 <a href="#t_floating">floating point</a>,
1206 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1207 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1208 <a href="#t_struct">structure</a>,
1209 <a href="#t_array">array</a>,
Dan Gohmand13951e2008-05-23 22:50:26 +0000[diff] [blame]1210 <a href="#t_label">label</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1211 </td>
1212 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1213 <tr>
1214 <td><a href="#t_primitive">primitive</a></td>
1215 <td><a href="#t_label">label</a>,
1216 <a href="#t_void">void</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1217 <a href="#t_floating">floating point</a>.</td>
1218 </tr>
1219 <tr>
1220 <td><a href="#t_derived">derived</a></td>
1221 <td><a href="#t_integer">integer</a>,
1222 <a href="#t_array">array</a>,
1223 <a href="#t_function">function</a>,
1224 <a href="#t_pointer">pointer</a>,
1225 <a href="#t_struct">structure</a>,
1226 <a href="#t_pstruct">packed structure</a>,
1227 <a href="#t_vector">vector</a>,
1228 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1229 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1230 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1231 </tbody>
1232</table>
1233
1234<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1235most important. Values of these types are the only ones which can be
1236produced by instructions, passed as arguments, or used as operands to
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]1237instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1238</div>
1239
1240<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1241<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1242
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1243<div class="doc_text">
1244<p>The primitive types are the fundamental building blocks of the LLVM
1245system.</p>
1246
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1247</div>
1248
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1249<!-- _______________________________________________________________________ -->
1250<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1251
1252<div class="doc_text">
1253 <table>
1254 <tbody>
1255 <tr><th>Type</th><th>Description</th></tr>
1256 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1257 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1258 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1259 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1260 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1261 </tbody>
1262 </table>
1263</div>
1264
1265<!-- _______________________________________________________________________ -->
1266<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1267
1268<div class="doc_text">
1269<h5>Overview:</h5>
1270<p>The void type does not represent any value and has no size.</p>
1271
1272<h5>Syntax:</h5>
1273
1274<pre>
1275 void
1276</pre>
1277</div>
1278
1279<!-- _______________________________________________________________________ -->
1280<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1281
1282<div class="doc_text">
1283<h5>Overview:</h5>
1284<p>The label type represents code labels.</p>
1285
1286<h5>Syntax:</h5>
1287
1288<pre>
1289 label
1290</pre>
1291</div>
1292
1293
1294<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1295<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1296
1297<div class="doc_text">
1298
1299<p>The real power in LLVM comes from the derived types in the system.
1300This is what allows a programmer to represent arrays, functions,
1301pointers, and other useful types. Note that these derived types may be
1302recursive: For example, it is possible to have a two dimensional array.</p>
1303
1304</div>
1305
1306<!-- _______________________________________________________________________ -->
1307<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1308
1309<div class="doc_text">
1310
1311<h5>Overview:</h5>
1312<p>The integer type is a very simple derived type that simply specifies an
1313arbitrary bit width for the integer type desired. Any bit width from 1 bit to
13142^23-1 (about 8 million) can be specified.</p>
1315
1316<h5>Syntax:</h5>
1317
1318<pre>
1319 iN
1320</pre>
1321
1322<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1323value.</p>
1324
1325<h5>Examples:</h5>
1326<table class="layout">
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1327 <tbody>
1328 <tr>
1329 <td><tt>i1</tt></td>
1330 <td>a single-bit integer.</td>
1331 </tr><tr>
1332 <td><tt>i32</tt></td>
1333 <td>a 32-bit integer.</td>
1334 </tr><tr>
1335 <td><tt>i1942652</tt></td>
1336 <td>a really big integer of over 1 million bits.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1337 </tr>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1338 </tbody>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1339</table>
1340</div>
1341
1342<!-- _______________________________________________________________________ -->
1343<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1344
1345<div class="doc_text">
1346
1347<h5>Overview:</h5>
1348
1349<p>The array type is a very simple derived type that arranges elements
1350sequentially in memory. The array type requires a size (number of
1351elements) and an underlying data type.</p>
1352
1353<h5>Syntax:</h5>
1354
1355<pre>
1356 [&lt;# elements&gt; x &lt;elementtype&gt;]
1357</pre>
1358
1359<p>The number of elements is a constant integer value; elementtype may
1360be any type with a size.</p>
1361
1362<h5>Examples:</h5>
1363<table class="layout">
1364 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1365 <td class="left"><tt>[40 x i32]</tt></td>
1366 <td class="left">Array of 40 32-bit integer values.</td>
1367 </tr>
1368 <tr class="layout">
1369 <td class="left"><tt>[41 x i32]</tt></td>
1370 <td class="left">Array of 41 32-bit integer values.</td>
1371 </tr>
1372 <tr class="layout">
1373 <td class="left"><tt>[4 x i8]</tt></td>
1374 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1375 </tr>
1376</table>
1377<p>Here are some examples of multidimensional arrays:</p>
1378<table class="layout">
1379 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1380 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1381 <td class="left">3x4 array of 32-bit integer values.</td>
1382 </tr>
1383 <tr class="layout">
1384 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1385 <td class="left">12x10 array of single precision floating point values.</td>
1386 </tr>
1387 <tr class="layout">
1388 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1389 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1390 </tr>
1391</table>
1392
1393<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1394length array. Normally, accesses past the end of an array are undefined in
1395LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1396As a special case, however, zero length arrays are recognized to be variable
1397length. This allows implementation of 'pascal style arrays' with the LLVM
1398type "{ i32, [0 x float]}", for example.</p>
1399
1400</div>
1401
1402<!-- _______________________________________________________________________ -->
1403<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
1404<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1405
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1406<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1407
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1408<p>The function type can be thought of as a function signature. It
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1409consists of a return type and a list of formal parameter types. The
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1410return 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]1411If 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]1412class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1413
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1414<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1415
1416<pre>
1417 &lt;returntype list&gt; (&lt;parameter list&gt;)
1418</pre>
1419
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1420<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
1421specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1422which indicates that the function takes a variable number of arguments.
1423Variable argument functions can access their arguments with the <a
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1424 href="#int_varargs">variable argument handling intrinsic</a> functions.
1425'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1426<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1427
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1428<h5>Examples:</h5>
1429<table class="layout">
1430 <tr class="layout">
1431 <td class="left"><tt>i32 (i32)</tt></td>
1432 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1433 </td>
1434 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1435 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1436 </tt></td>
1437 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1438 an <tt>i16</tt> that should be sign extended and a
1439 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1440 <tt>float</tt>.
1441 </td>
1442 </tr><tr class="layout">
1443 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1444 <td class="left">A vararg function that takes at least one
1445 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1446 which returns an integer. This is the signature for <tt>printf</tt> in
1447 LLVM.
1448 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1449 </tr><tr class="layout">
1450 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Misha Brukmanafc88b02008-11-27 06:41:20 +0000[diff] [blame]1451 <td class="left">A function taking an <tt>i32</tt>, returning two
1452 <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1453 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1454 </tr>
1455</table>
1456
1457</div>
1458<!-- _______________________________________________________________________ -->
1459<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
1460<div class="doc_text">
1461<h5>Overview:</h5>
1462<p>The structure type is used to represent a collection of data members
1463together in memory. The packing of the field types is defined to match
1464the ABI of the underlying processor. The elements of a structure may
1465be any type that has a size.</p>
1466<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1467and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1468field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1469instruction.</p>
1470<h5>Syntax:</h5>
1471<pre> { &lt;type list&gt; }<br></pre>
1472<h5>Examples:</h5>
1473<table class="layout">
1474 <tr class="layout">
1475 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1476 <td class="left">A triple of three <tt>i32</tt> values</td>
1477 </tr><tr class="layout">
1478 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1479 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1480 second element is a <a href="#t_pointer">pointer</a> to a
1481 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1482 an <tt>i32</tt>.</td>
1483 </tr>
1484</table>
1485</div>
1486
1487<!-- _______________________________________________________________________ -->
1488<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1489</div>
1490<div class="doc_text">
1491<h5>Overview:</h5>
1492<p>The packed structure type is used to represent a collection of data members
1493together in memory. There is no padding between fields. Further, the alignment
1494of a packed structure is 1 byte. The elements of a packed structure may
1495be any type that has a size.</p>
1496<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1497and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1498field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1499instruction.</p>
1500<h5>Syntax:</h5>
1501<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1502<h5>Examples:</h5>
1503<table class="layout">
1504 <tr class="layout">
1505 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1506 <td class="left">A triple of three <tt>i32</tt> values</td>
1507 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1508 <td class="left">
1509<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1510 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1511 second element is a <a href="#t_pointer">pointer</a> to a
1512 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1513 an <tt>i32</tt>.</td>
1514 </tr>
1515</table>
1516</div>
1517
1518<!-- _______________________________________________________________________ -->
1519<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
1520<div class="doc_text">
1521<h5>Overview:</h5>
1522<p>As in many languages, the pointer type represents a pointer or
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]1523reference to another object, which must live in memory. Pointer types may have
1524an optional address space attribute defining the target-specific numbered
1525address space where the pointed-to object resides. The default address space is
1526zero.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1527<h5>Syntax:</h5>
1528<pre> &lt;type&gt; *<br></pre>
1529<h5>Examples:</h5>
1530<table class="layout">
1531 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1532 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1533 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1534 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1535 </tr>
1536 <tr class="layout">
1537 <td class="left"><tt>i32 (i32 *) *</tt></td>
1538 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1539 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1540 <tt>i32</tt>.</td>
1541 </tr>
1542 <tr class="layout">
1543 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1544 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1545 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1546 </tr>
1547</table>
1548</div>
1549
1550<!-- _______________________________________________________________________ -->
1551<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
1552<div class="doc_text">
1553
1554<h5>Overview:</h5>
1555
1556<p>A vector type is a simple derived type that represents a vector
1557of elements. Vector types are used when multiple primitive data
1558are operated in parallel using a single instruction (SIMD).
1559A vector type requires a size (number of
1560elements) and an underlying primitive data type. Vectors must have a power
1561of two length (1, 2, 4, 8, 16 ...). Vector types are
1562considered <a href="#t_firstclass">first class</a>.</p>
1563
1564<h5>Syntax:</h5>
1565
1566<pre>
1567 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1568</pre>
1569
1570<p>The number of elements is a constant integer value; elementtype may
1571be any integer or floating point type.</p>
1572
1573<h5>Examples:</h5>
1574
1575<table class="layout">
1576 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1577 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1578 <td class="left">Vector of 4 32-bit integer values.</td>
1579 </tr>
1580 <tr class="layout">
1581 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1582 <td class="left">Vector of 8 32-bit floating-point values.</td>
1583 </tr>
1584 <tr class="layout">
1585 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1586 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1587 </tr>
1588</table>
1589</div>
1590
1591<!-- _______________________________________________________________________ -->
1592<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1593<div class="doc_text">
1594
1595<h5>Overview:</h5>
1596
1597<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksenda0706e2007-10-14 00:34:53 +0000[diff] [blame]1598corresponds (for example) to the C notion of a forward declared structure type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1599In LLVM, opaque types can eventually be resolved to any type (not just a
1600structure type).</p>
1601
1602<h5>Syntax:</h5>
1603
1604<pre>
1605 opaque
1606</pre>
1607
1608<h5>Examples:</h5>
1609
1610<table class="layout">
1611 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1612 <td class="left"><tt>opaque</tt></td>
1613 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1614 </tr>
1615</table>
1616</div>
1617
1618
1619<!-- *********************************************************************** -->
1620<div class="doc_section"> <a name="constants">Constants</a> </div>
1621<!-- *********************************************************************** -->
1622
1623<div class="doc_text">
1624
1625<p>LLVM has several different basic types of constants. This section describes
1626them all and their syntax.</p>
1627
1628</div>
1629
1630<!-- ======================================================================= -->
1631<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1632
1633<div class="doc_text">
1634
1635<dl>
1636 <dt><b>Boolean constants</b></dt>
1637
1638 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1639 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
1640 </dd>
1641
1642 <dt><b>Integer constants</b></dt>
1643
1644 <dd>Standard integers (such as '4') are constants of the <a
1645 href="#t_integer">integer</a> type. Negative numbers may be used with
1646 integer types.
1647 </dd>
1648
1649 <dt><b>Floating point constants</b></dt>
1650
1651 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1652 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]1653 notation (see below). The assembler requires the exact decimal value of
1654 a floating-point constant. For example, the assembler accepts 1.25 but
1655 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1656 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1657
1658 <dt><b>Null pointer constants</b></dt>
1659
1660 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
1661 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1662
1663</dl>
1664
1665<p>The one non-intuitive notation for constants is the optional hexadecimal form
1666of floating point constants. For example, the form '<tt>double
16670x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
16684.5e+15</tt>'. The only time hexadecimal floating point constants are required
1669(and the only time that they are generated by the disassembler) is when a
1670floating point constant must be emitted but it cannot be represented as a
1671decimal floating point number. For example, NaN's, infinities, and other
1672special values are represented in their IEEE hexadecimal format so that
1673assembly and disassembly do not cause any bits to change in the constants.</p>
1674
1675</div>
1676
1677<!-- ======================================================================= -->
1678<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1679</div>
1680
1681<div class="doc_text">
1682<p>Aggregate constants arise from aggregation of simple constants
1683and smaller aggregate constants.</p>
1684
1685<dl>
1686 <dt><b>Structure constants</b></dt>
1687
1688 <dd>Structure constants are represented with notation similar to structure
1689 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner6c8de962007-12-25 20:34:52 +0000[diff] [blame]1690 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1691 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]1692 must have <a href="#t_struct">structure type</a>, and the number and
1693 types of elements must match those specified by the type.
1694 </dd>
1695
1696 <dt><b>Array constants</b></dt>
1697
1698 <dd>Array constants are represented with notation similar to array type
1699 definitions (a comma separated list of elements, surrounded by square brackets
1700 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
1701 constants must have <a href="#t_array">array type</a>, and the number and
1702 types of elements must match those specified by the type.
1703 </dd>
1704
1705 <dt><b>Vector constants</b></dt>
1706
1707 <dd>Vector constants are represented with notation similar to vector type
1708 definitions (a comma separated list of elements, surrounded by
1709 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1710 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
1711 href="#t_vector">vector type</a>, and the number and types of elements must
1712 match those specified by the type.
1713 </dd>
1714
1715 <dt><b>Zero initialization</b></dt>
1716
1717 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1718 value to zero of <em>any</em> type, including scalar and aggregate types.
1719 This is often used to avoid having to print large zero initializers (e.g. for
1720 large arrays) and is always exactly equivalent to using explicit zero
1721 initializers.
1722 </dd>
1723</dl>
1724
1725</div>
1726
1727<!-- ======================================================================= -->
1728<div class="doc_subsection">
1729 <a name="globalconstants">Global Variable and Function Addresses</a>
1730</div>
1731
1732<div class="doc_text">
1733
1734<p>The addresses of <a href="#globalvars">global variables</a> and <a
1735href="#functionstructure">functions</a> are always implicitly valid (link-time)
1736constants. These constants are explicitly referenced when the <a
1737href="#identifiers">identifier for the global</a> is used and always have <a
1738href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1739file:</p>
1740
1741<div class="doc_code">
1742<pre>
1743@X = global i32 17
1744@Y = global i32 42
1745@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
1746</pre>
1747</div>
1748
1749</div>
1750
1751<!-- ======================================================================= -->
1752<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
1753<div class="doc_text">
1754 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
1755 no specific value. Undefined values may be of any type and be used anywhere
1756 a constant is permitted.</p>
1757
1758 <p>Undefined values indicate to the compiler that the program is well defined
1759 no matter what value is used, giving the compiler more freedom to optimize.
1760 </p>
1761</div>
1762
1763<!-- ======================================================================= -->
1764<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1765</div>
1766
1767<div class="doc_text">
1768
1769<p>Constant expressions are used to allow expressions involving other constants
1770to be used as constants. Constant expressions may be of any <a
1771href="#t_firstclass">first class</a> type and may involve any LLVM operation
1772that does not have side effects (e.g. load and call are not supported). The
1773following is the syntax for constant expressions:</p>
1774
1775<dl>
1776 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1777 <dd>Truncate a constant to another type. The bit size of CST must be larger
1778 than the bit size of TYPE. Both types must be integers.</dd>
1779
1780 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1781 <dd>Zero extend a constant to another type. The bit size of CST must be
1782 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1783
1784 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1785 <dd>Sign extend a constant to another type. The bit size of CST must be
1786 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1787
1788 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1789 <dd>Truncate a floating point constant to another floating point type. The
1790 size of CST must be larger than the size of TYPE. Both types must be
1791 floating point.</dd>
1792
1793 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1794 <dd>Floating point extend a constant to another type. The size of CST must be
1795 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1796
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]1797 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1798 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1799 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1800 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1801 of the same number of elements. If the value won't fit in the integer type,
1802 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1803
1804 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
1805 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1806 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1807 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1808 of the same number of elements. If the value won't fit in the integer type,
1809 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1810
1811 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
1812 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1813 constant. TYPE must be a scalar or vector floating point type. CST must be of
1814 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1815 of the same number of elements. If the value won't fit in the floating point
1816 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1817
1818 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
1819 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1820 constant. TYPE must be a scalar or vector floating point type. CST must be of
1821 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1822 of the same number of elements. If the value won't fit in the floating point
1823 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1824
1825 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1826 <dd>Convert a pointer typed constant to the corresponding integer constant
1827 TYPE must be an integer type. CST must be of pointer type. The CST value is
1828 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1829
1830 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1831 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1832 pointer type. CST must be of integer type. The CST value is zero extended,
1833 truncated, or unchanged to make it fit in a pointer size. This one is
1834 <i>really</i> dangerous!</dd>
1835
1836 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
1837 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1838 identical (same number of bits). The conversion is done as if the CST value
1839 was stored to memory and read back as TYPE. In other words, no bits change
1840 with this operator, just the type. This can be used for conversion of
1841 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]1842 pointers it is only valid to cast to another pointer type. It is not valid
1843 to bitcast to or from an aggregate type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1844 </dd>
1845
1846 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1847
1848 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1849 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1850 instruction, the index list may have zero or more indexes, which are required
1851 to make sense for the type of "CSTPTR".</dd>
1852
1853 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1854
1855 <dd>Perform the <a href="#i_select">select operation</a> on
1856 constants.</dd>
1857
1858 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1859 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1860
1861 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1862 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
1863
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]1864 <dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
1865 <dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
1866
1867 <dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
1868 <dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
1869
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1870 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1871
1872 <dd>Perform the <a href="#i_extractelement">extractelement
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1873 operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1874
1875 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1876
1877 <dd>Perform the <a href="#i_insertelement">insertelement
1878 operation</a> on constants.</dd>
1879
1880
1881 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1882
1883 <dd>Perform the <a href="#i_shufflevector">shufflevector
1884 operation</a> on constants.</dd>
1885
1886 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1887
1888 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1889 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
1890 binary</a> operations. The constraints on operands are the same as those for
1891 the corresponding instruction (e.g. no bitwise operations on floating point
1892 values are allowed).</dd>
1893</dl>
1894</div>
1895
1896<!-- *********************************************************************** -->
1897<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1898<!-- *********************************************************************** -->
1899
1900<!-- ======================================================================= -->
1901<div class="doc_subsection">
1902<a name="inlineasm">Inline Assembler Expressions</a>
1903</div>
1904
1905<div class="doc_text">
1906
1907<p>
1908LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1909Module-Level Inline Assembly</a>) through the use of a special value. This
1910value represents the inline assembler as a string (containing the instructions
1911to emit), a list of operand constraints (stored as a string), and a flag that
1912indicates whether or not the inline asm expression has side effects. An example
1913inline assembler expression is:
1914</p>
1915
1916<div class="doc_code">
1917<pre>
1918i32 (i32) asm "bswap $0", "=r,r"
1919</pre>
1920</div>
1921
1922<p>
1923Inline assembler expressions may <b>only</b> be used as the callee operand of
1924a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1925</p>
1926
1927<div class="doc_code">
1928<pre>
1929%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
1930</pre>
1931</div>
1932
1933<p>
1934Inline asms with side effects not visible in the constraint list must be marked
1935as having side effects. This is done through the use of the
1936'<tt>sideeffect</tt>' keyword, like so:
1937</p>
1938
1939<div class="doc_code">
1940<pre>
1941call void asm sideeffect "eieio", ""()
1942</pre>
1943</div>
1944
1945<p>TODO: The format of the asm and constraints string still need to be
1946documented here. Constraints on what can be done (e.g. duplication, moving, etc
Chris Lattner1cdd64e2008-10-04 18:36:02 +0000[diff] [blame]1947need to be documented). This is probably best done by reference to another
1948document that covers inline asm from a holistic perspective.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1949</p>
1950
1951</div>
1952
1953<!-- *********************************************************************** -->
1954<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1955<!-- *********************************************************************** -->
1956
1957<div class="doc_text">
1958
1959<p>The LLVM instruction set consists of several different
1960classifications of instructions: <a href="#terminators">terminator
1961instructions</a>, <a href="#binaryops">binary instructions</a>,
1962<a href="#bitwiseops">bitwise binary instructions</a>, <a
1963 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1964instructions</a>.</p>
1965
1966</div>
1967
1968<!-- ======================================================================= -->
1969<div class="doc_subsection"> <a name="terminators">Terminator
1970Instructions</a> </div>
1971
1972<div class="doc_text">
1973
1974<p>As mentioned <a href="#functionstructure">previously</a>, every
1975basic block in a program ends with a "Terminator" instruction, which
1976indicates which block should be executed after the current block is
1977finished. These terminator instructions typically yield a '<tt>void</tt>'
1978value: they produce control flow, not values (the one exception being
1979the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
1980<p>There are six different terminator instructions: the '<a
1981 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1982instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
1983the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1984 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1985 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
1986
1987</div>
1988
1989<!-- _______________________________________________________________________ -->
1990<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1991Instruction</a> </div>
1992<div class="doc_text">
1993<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]1994<pre>
1995 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]1996 ret void <i>; Return from void function</i>
1997</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1998
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1999<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2000
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2001<p>The '<tt>ret</tt>' instruction is used to return control flow (and
2002optionally a value) from a function back to the caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2003<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2004returns a value and then causes control flow, and one that just causes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2005control flow to occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2006
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2007<h5>Arguments:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2008
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2009<p>The '<tt>ret</tt>' instruction optionally accepts a single argument,
2010the return value. The type of the return value must be a
2011'<a href="#t_firstclass">first class</a>' type.</p>
2012
2013<p>A function is not <a href="#wellformed">well formed</a> if
2014it it has a non-void return type and contains a '<tt>ret</tt>'
2015instruction with no return value or a return value with a type that
2016does not match its type, or if it has a void return type and contains
2017a '<tt>ret</tt>' instruction with a return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2018
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2019<h5>Semantics:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2020
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2021<p>When the '<tt>ret</tt>' instruction is executed, control flow
2022returns back to the calling function's context. If the caller is a "<a
2023 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
2024the instruction after the call. If the caller was an "<a
2025 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
2026at the beginning of the "normal" destination block. If the instruction
2027returns a value, that value shall set the call or invoke instruction's
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2028return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2029
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2030<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2031
2032<pre>
2033 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2034 ret void <i>; Return from a void function</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2035 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]2036</pre>
2037</div>
2038<!-- _______________________________________________________________________ -->
2039<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
2040<div class="doc_text">
2041<h5>Syntax:</h5>
2042<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
2043</pre>
2044<h5>Overview:</h5>
2045<p>The '<tt>br</tt>' instruction is used to cause control flow to
2046transfer to a different basic block in the current function. There are
2047two forms of this instruction, corresponding to a conditional branch
2048and an unconditional branch.</p>
2049<h5>Arguments:</h5>
2050<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
2051single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
2052unconditional form of the '<tt>br</tt>' instruction takes a single
2053'<tt>label</tt>' value as a target.</p>
2054<h5>Semantics:</h5>
2055<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
2056argument is evaluated. If the value is <tt>true</tt>, control flows
2057to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2058control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2059<h5>Example:</h5>
2060<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
2061 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
2062</div>
2063<!-- _______________________________________________________________________ -->
2064<div class="doc_subsubsection">
2065 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2066</div>
2067
2068<div class="doc_text">
2069<h5>Syntax:</h5>
2070
2071<pre>
2072 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2073</pre>
2074
2075<h5>Overview:</h5>
2076
2077<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
2078several different places. It is a generalization of the '<tt>br</tt>'
2079instruction, allowing a branch to occur to one of many possible
2080destinations.</p>
2081
2082
2083<h5>Arguments:</h5>
2084
2085<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
2086comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
2087an array of pairs of comparison value constants and '<tt>label</tt>'s. The
2088table is not allowed to contain duplicate constant entries.</p>
2089
2090<h5>Semantics:</h5>
2091
2092<p>The <tt>switch</tt> instruction specifies a table of values and
2093destinations. When the '<tt>switch</tt>' instruction is executed, this
2094table is searched for the given value. If the value is found, control flow is
2095transfered to the corresponding destination; otherwise, control flow is
2096transfered to the default destination.</p>
2097
2098<h5>Implementation:</h5>
2099
2100<p>Depending on properties of the target machine and the particular
2101<tt>switch</tt> instruction, this instruction may be code generated in different
2102ways. For example, it could be generated as a series of chained conditional
2103branches or with a lookup table.</p>
2104
2105<h5>Example:</h5>
2106
2107<pre>
2108 <i>; Emulate a conditional br instruction</i>
2109 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2110 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2111
2112 <i>; Emulate an unconditional br instruction</i>
2113 switch i32 0, label %dest [ ]
2114
2115 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2116 switch i32 %val, label %otherwise [ i32 0, label %onzero
2117 i32 1, label %onone
2118 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2119</pre>
2120</div>
2121
2122<!-- _______________________________________________________________________ -->
2123<div class="doc_subsubsection">
2124 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2125</div>
2126
2127<div class="doc_text">
2128
2129<h5>Syntax:</h5>
2130
2131<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2132 &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]2133 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2134</pre>
2135
2136<h5>Overview:</h5>
2137
2138<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
2139function, with the possibility of control flow transfer to either the
2140'<tt>normal</tt>' label or the
2141'<tt>exception</tt>' label. If the callee function returns with the
2142"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
2143"normal" label. If the callee (or any indirect callees) returns with the "<a
2144href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2145continued at the dynamically nearest "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2146
2147<h5>Arguments:</h5>
2148
2149<p>This instruction requires several arguments:</p>
2150
2151<ol>
2152 <li>
2153 The optional "cconv" marker indicates which <a href="#callingconv">calling
2154 convention</a> the call should use. If none is specified, the call defaults
2155 to using C calling conventions.
2156 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2157
2158 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
2159 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
2160 and '<tt>inreg</tt>' attributes are valid here.</li>
2161
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2162 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
2163 function value being invoked. In most cases, this is a direct function
2164 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
2165 an arbitrary pointer to function value.
2166 </li>
2167
2168 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
2169 function to be invoked. </li>
2170
2171 <li>'<tt>function args</tt>': argument list whose types match the function
2172 signature argument types. If the function signature indicates the function
2173 accepts a variable number of arguments, the extra arguments can be
2174 specified. </li>
2175
2176 <li>'<tt>normal label</tt>': the label reached when the called function
2177 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2178
2179 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2180 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2181
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2182 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2183 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2184 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2185</ol>
2186
2187<h5>Semantics:</h5>
2188
2189<p>This instruction is designed to operate as a standard '<tt><a
2190href="#i_call">call</a></tt>' instruction in most regards. The primary
2191difference is that it establishes an association with a label, which is used by
2192the runtime library to unwind the stack.</p>
2193
2194<p>This instruction is used in languages with destructors to ensure that proper
2195cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2196exception. Additionally, this is important for implementation of
2197'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2198
2199<h5>Example:</h5>
2200<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2201 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2202 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2203 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2204 unwind label %TestCleanup <i>; {i32}:retval set</i>
2205</pre>
2206</div>
2207
2208
2209<!-- _______________________________________________________________________ -->
2210
2211<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2212Instruction</a> </div>
2213
2214<div class="doc_text">
2215
2216<h5>Syntax:</h5>
2217<pre>
2218 unwind
2219</pre>
2220
2221<h5>Overview:</h5>
2222
2223<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2224at the first callee in the dynamic call stack which used an <a
2225href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2226primarily used to implement exception handling.</p>
2227
2228<h5>Semantics:</h5>
2229
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2230<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2231immediately halt. The dynamic call stack is then searched for the first <a
2232href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2233execution continues at the "exceptional" destination block specified by the
2234<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2235dynamic call chain, undefined behavior results.</p>
2236</div>
2237
2238<!-- _______________________________________________________________________ -->
2239
2240<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2241Instruction</a> </div>
2242
2243<div class="doc_text">
2244
2245<h5>Syntax:</h5>
2246<pre>
2247 unreachable
2248</pre>
2249
2250<h5>Overview:</h5>
2251
2252<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2253instruction is used to inform the optimizer that a particular portion of the
2254code is not reachable. This can be used to indicate that the code after a
2255no-return function cannot be reached, and other facts.</p>
2256
2257<h5>Semantics:</h5>
2258
2259<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2260</div>
2261
2262
2263
2264<!-- ======================================================================= -->
2265<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
2266<div class="doc_text">
2267<p>Binary operators are used to do most of the computation in a
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2268program. They require two operands of the same type, execute an operation on them, and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2269produce a single value. The operands might represent
2270multiple 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]2271The result value has the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2272<p>There are several different binary operators:</p>
2273</div>
2274<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2275<div class="doc_subsubsection">
2276 <a name="i_add">'<tt>add</tt>' Instruction</a>
2277</div>
2278
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2279<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2280
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2281<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2282
2283<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2284 &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]2285</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2286
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2287<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2288
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2289<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2290
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2291<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2292
2293<p>The two arguments to the '<tt>add</tt>' instruction must be <a
2294 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
2295 <a href="#t_vector">vector</a> values. Both arguments must have identical
2296 types.</p>
2297
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2298<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2299
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2300<p>The value produced is the integer or floating point sum of the two
2301operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2302
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2303<p>If an integer sum has unsigned overflow, the result returned is the
2304mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2305the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2306
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2307<p>Because LLVM integers use a two's complement representation, this
2308instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2309
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2310<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2311
2312<pre>
2313 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2314</pre>
2315</div>
2316<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2317<div class="doc_subsubsection">
2318 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2319</div>
2320
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2321<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2322
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2323<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2324
2325<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2326 &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]2327</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2328
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2329<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2330
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2331<p>The '<tt>sub</tt>' instruction returns the difference of its two
2332operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2333
2334<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2335'<tt>neg</tt>' instruction present in most other intermediate
2336representations.</p>
2337
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2338<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2339
2340<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
2341 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2342 or <a href="#t_vector">vector</a> values. Both arguments must have identical
2343 types.</p>
2344
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2345<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2346
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2347<p>The value produced is the integer or floating point difference of
2348the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2349
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2350<p>If an integer difference has unsigned overflow, the result returned is the
2351mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2352the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2353
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2354<p>Because LLVM integers use a two's complement representation, this
2355instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2356
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2357<h5>Example:</h5>
2358<pre>
2359 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2360 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2361</pre>
2362</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2363
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2364<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2365<div class="doc_subsubsection">
2366 <a name="i_mul">'<tt>mul</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>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2372<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]2373</pre>
2374<h5>Overview:</h5>
2375<p>The '<tt>mul</tt>' instruction returns the product of its two
2376operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2377
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2378<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2379
2380<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
2381href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2382or <a href="#t_vector">vector</a> values. Both arguments must have identical
2383types.</p>
2384
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2385<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2386
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2387<p>The value produced is the integer or floating point product of the
2388two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2389
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2390<p>If the result of an integer multiplication has unsigned overflow,
2391the result returned is the mathematical result modulo
23922<sup>n</sup>, where n is the bit width of the result.</p>
2393<p>Because LLVM integers use a two's complement representation, and the
2394result is the same width as the operands, this instruction returns the
2395correct result for both signed and unsigned integers. If a full product
2396(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2397should be sign-extended or zero-extended as appropriate to the
2398width of the full product.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2399<h5>Example:</h5>
2400<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
2401</pre>
2402</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2403
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2404<!-- _______________________________________________________________________ -->
2405<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2406</a></div>
2407<div class="doc_text">
2408<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2409<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]2410</pre>
2411<h5>Overview:</h5>
2412<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2413operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2414
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2415<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2416
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2417<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2418<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2419values. Both arguments must have identical types.</p>
2420
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2421<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2422
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2423<p>The value produced is the unsigned integer quotient of the two operands.</p>
2424<p>Note that unsigned integer division and signed integer division are distinct
2425operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2426<p>Division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2427<h5>Example:</h5>
2428<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2429</pre>
2430</div>
2431<!-- _______________________________________________________________________ -->
2432<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2433</a> </div>
2434<div class="doc_text">
2435<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2436<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2437 &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]2438</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2439
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2440<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2441
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2442<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2443operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2444
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2445<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2446
2447<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2448<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2449values. Both arguments must have identical types.</p>
2450
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2451<h5>Semantics:</h5>
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2452<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]2453<p>Note that signed integer division and unsigned integer division are distinct
2454operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2455<p>Division by zero leads to undefined behavior. Overflow also leads to
2456undefined behavior; this is a rare case, but can occur, for example,
2457by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2458<h5>Example:</h5>
2459<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2460</pre>
2461</div>
2462<!-- _______________________________________________________________________ -->
2463<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2464Instruction</a> </div>
2465<div class="doc_text">
2466<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2467<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2468 &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]2469</pre>
2470<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2471
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2472<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
2473operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2474
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2475<h5>Arguments:</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 two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2478<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2479of floating point values. Both arguments must have identical types.</p>
2480
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2481<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2482
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2483<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2484
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2485<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2486
2487<pre>
2488 &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]2489</pre>
2490</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2491
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2492<!-- _______________________________________________________________________ -->
2493<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2494</div>
2495<div class="doc_text">
2496<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2497<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]2498</pre>
2499<h5>Overview:</h5>
2500<p>The '<tt>urem</tt>' instruction returns the remainder from the
2501unsigned division of its two arguments.</p>
2502<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2503<p>The two arguments to the '<tt>urem</tt>' instruction must be
2504<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2505values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2506<h5>Semantics:</h5>
2507<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2508This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2509<p>Note that unsigned integer remainder and signed integer remainder are
2510distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2511<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2512<h5>Example:</h5>
2513<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2514</pre>
2515
2516</div>
2517<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2518<div class="doc_subsubsection">
2519 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2520</div>
2521
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2522<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2523
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2524<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2525
2526<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2527 &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]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>srem</tt>' instruction returns the remainder from the
Dan Gohman3e3fd8c2007-11-05 23:35:22 +0000[diff] [blame]2533signed division of its two operands. This instruction can also take
2534<a href="#t_vector">vector</a> versions of the values in which case
2535the elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]2536
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2537<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2538
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2539<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2540<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2541values. Both arguments must have identical types.</p>
2542
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2543<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2544
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2545<p>This instruction returns the <i>remainder</i> of a division (where the result
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2546has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
2547operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2548a value. For more information about the difference, see <a
2549 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2550Math Forum</a>. For a table of how this is implemented in various languages,
2551please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
2552Wikipedia: modulo operation</a>.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2553<p>Note that signed integer remainder and unsigned integer remainder are
2554distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2555<p>Taking the remainder of a division by zero leads to undefined behavior.
2556Overflow also leads to undefined behavior; this is a rare case, but can occur,
2557for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2558(The remainder doesn't actually overflow, but this rule lets srem be
2559implemented using instructions that return both the result of the division
2560and the remainder.)</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2561<h5>Example:</h5>
2562<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2563</pre>
2564
2565</div>
2566<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2567<div class="doc_subsubsection">
2568 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2569
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2570<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2571
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2572<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2573<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]2574</pre>
2575<h5>Overview:</h5>
2576<p>The '<tt>frem</tt>' instruction returns the remainder from the
2577division of its two operands.</p>
2578<h5>Arguments:</h5>
2579<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2580<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2581of floating point values. Both arguments must have identical types.</p>
2582
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2583<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2584
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2585<p>This instruction returns the <i>remainder</i> of a division.
2586The remainder has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2587
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2588<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2589
2590<pre>
2591 &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]2592</pre>
2593</div>
2594
2595<!-- ======================================================================= -->
2596<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2597Operations</a> </div>
2598<div class="doc_text">
2599<p>Bitwise binary operators are used to do various forms of
2600bit-twiddling in a program. They are generally very efficient
2601instructions and can commonly be strength reduced from other
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2602instructions. They require two operands of the same type, execute an operation on them,
2603and 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]2604</div>
2605
2606<!-- _______________________________________________________________________ -->
2607<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2608Instruction</a> </div>
2609<div class="doc_text">
2610<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2611<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]2612</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2613
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2614<h5>Overview:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2615
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2616<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2617the left a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2618
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2619<h5>Arguments:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2620
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2621<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2622 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2623type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2624
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2625<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2626
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2627<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
2628where 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]2629equal to or larger than the number of bits in <tt>op1</tt>, the result is undefined.
2630If the arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2631corresponding shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2632
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2633<h5>Example:</h5><pre>
2634 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2635 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2636 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2637 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2638 &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]2639</pre>
2640</div>
2641<!-- _______________________________________________________________________ -->
2642<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2643Instruction</a> </div>
2644<div class="doc_text">
2645<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2646<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]2647</pre>
2648
2649<h5>Overview:</h5>
2650<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2651operand shifted to the right a specified number of bits with zero fill.</p>
2652
2653<h5>Arguments:</h5>
2654<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2655<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]2656type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2657
2658<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2659
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2660<p>This instruction always performs a logical shift right operation. The most
2661significant bits of the result will be filled with zero bits after the
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2662shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2663the number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
2664vectors, each vector element of <tt>op1</tt> is shifted by the corresponding shift
2665amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2666
2667<h5>Example:</h5>
2668<pre>
2669 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2670 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2671 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2672 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2673 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2674 &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]2675</pre>
2676</div>
2677
2678<!-- _______________________________________________________________________ -->
2679<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2680Instruction</a> </div>
2681<div class="doc_text">
2682
2683<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2684<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]2685</pre>
2686
2687<h5>Overview:</h5>
2688<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2689operand shifted to the right a specified number of bits with sign extension.</p>
2690
2691<h5>Arguments:</h5>
2692<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2693<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]2694type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2695
2696<h5>Semantics:</h5>
2697<p>This instruction always performs an arithmetic shift right operation,
2698The most significant bits of the result will be filled with the sign bit
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2699of <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]2700larger than the number of bits in <tt>op1</tt>, the result is undefined. If the
2701arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2702corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2703
2704<h5>Example:</h5>
2705<pre>
2706 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2707 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2708 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2709 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2710 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2711 &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]2712</pre>
2713</div>
2714
2715<!-- _______________________________________________________________________ -->
2716<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2717Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2718
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2719<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2720
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2721<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2722
2723<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2724 &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]2725</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2726
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2727<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2728
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2729<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2730its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2731
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2732<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2733
2734<p>The two arguments to the '<tt>and</tt>' instruction must be
2735<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2736values. Both arguments must have identical types.</p>
2737
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2738<h5>Semantics:</h5>
2739<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
2740<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2741<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2742<table border="1" cellspacing="0" cellpadding="4">
2743 <tbody>
2744 <tr>
2745 <td>In0</td>
2746 <td>In1</td>
2747 <td>Out</td>
2748 </tr>
2749 <tr>
2750 <td>0</td>
2751 <td>0</td>
2752 <td>0</td>
2753 </tr>
2754 <tr>
2755 <td>0</td>
2756 <td>1</td>
2757 <td>0</td>
2758 </tr>
2759 <tr>
2760 <td>1</td>
2761 <td>0</td>
2762 <td>0</td>
2763 </tr>
2764 <tr>
2765 <td>1</td>
2766 <td>1</td>
2767 <td>1</td>
2768 </tr>
2769 </tbody>
2770</table>
2771</div>
2772<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2773<pre>
2774 &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]2775 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2776 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
2777</pre>
2778</div>
2779<!-- _______________________________________________________________________ -->
2780<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
2781<div class="doc_text">
2782<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2783<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]2784</pre>
2785<h5>Overview:</h5>
2786<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2787or of its two operands.</p>
2788<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2789
2790<p>The two arguments to the '<tt>or</tt>' instruction must be
2791<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2792values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2793<h5>Semantics:</h5>
2794<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
2795<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2796<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2797<table border="1" cellspacing="0" cellpadding="4">
2798 <tbody>
2799 <tr>
2800 <td>In0</td>
2801 <td>In1</td>
2802 <td>Out</td>
2803 </tr>
2804 <tr>
2805 <td>0</td>
2806 <td>0</td>
2807 <td>0</td>
2808 </tr>
2809 <tr>
2810 <td>0</td>
2811 <td>1</td>
2812 <td>1</td>
2813 </tr>
2814 <tr>
2815 <td>1</td>
2816 <td>0</td>
2817 <td>1</td>
2818 </tr>
2819 <tr>
2820 <td>1</td>
2821 <td>1</td>
2822 <td>1</td>
2823 </tr>
2824 </tbody>
2825</table>
2826</div>
2827<h5>Example:</h5>
2828<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2829 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2830 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
2831</pre>
2832</div>
2833<!-- _______________________________________________________________________ -->
2834<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2835Instruction</a> </div>
2836<div class="doc_text">
2837<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2838<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]2839</pre>
2840<h5>Overview:</h5>
2841<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2842or of its two operands. The <tt>xor</tt> is used to implement the
2843"one's complement" operation, which is the "~" operator in C.</p>
2844<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2845<p>The two arguments to the '<tt>xor</tt>' instruction must be
2846<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2847values. Both arguments must have identical types.</p>
2848
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2849<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2850
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2851<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
2852<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2853<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2854<table border="1" cellspacing="0" cellpadding="4">
2855 <tbody>
2856 <tr>
2857 <td>In0</td>
2858 <td>In1</td>
2859 <td>Out</td>
2860 </tr>
2861 <tr>
2862 <td>0</td>
2863 <td>0</td>
2864 <td>0</td>
2865 </tr>
2866 <tr>
2867 <td>0</td>
2868 <td>1</td>
2869 <td>1</td>
2870 </tr>
2871 <tr>
2872 <td>1</td>
2873 <td>0</td>
2874 <td>1</td>
2875 </tr>
2876 <tr>
2877 <td>1</td>
2878 <td>1</td>
2879 <td>0</td>
2880 </tr>
2881 </tbody>
2882</table>
2883</div>
2884<p> </p>
2885<h5>Example:</h5>
2886<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2887 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2888 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2889 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
2890</pre>
2891</div>
2892
2893<!-- ======================================================================= -->
2894<div class="doc_subsection">
2895 <a name="vectorops">Vector Operations</a>
2896</div>
2897
2898<div class="doc_text">
2899
2900<p>LLVM supports several instructions to represent vector operations in a
2901target-independent manner. These instructions cover the element-access and
2902vector-specific operations needed to process vectors effectively. While LLVM
2903does directly support these vector operations, many sophisticated algorithms
2904will want to use target-specific intrinsics to take full advantage of a specific
2905target.</p>
2906
2907</div>
2908
2909<!-- _______________________________________________________________________ -->
2910<div class="doc_subsubsection">
2911 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2912</div>
2913
2914<div class="doc_text">
2915
2916<h5>Syntax:</h5>
2917
2918<pre>
2919 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
2920</pre>
2921
2922<h5>Overview:</h5>
2923
2924<p>
2925The '<tt>extractelement</tt>' instruction extracts a single scalar
2926element from a vector at a specified index.
2927</p>
2928
2929
2930<h5>Arguments:</h5>
2931
2932<p>
2933The first operand of an '<tt>extractelement</tt>' instruction is a
2934value of <a href="#t_vector">vector</a> type. The second operand is
2935an index indicating the position from which to extract the element.
2936The index may be a variable.</p>
2937
2938<h5>Semantics:</h5>
2939
2940<p>
2941The result is a scalar of the same type as the element type of
2942<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2943<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2944results are undefined.
2945</p>
2946
2947<h5>Example:</h5>
2948
2949<pre>
2950 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
2951</pre>
2952</div>
2953
2954
2955<!-- _______________________________________________________________________ -->
2956<div class="doc_subsubsection">
2957 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2958</div>
2959
2960<div class="doc_text">
2961
2962<h5>Syntax:</h5>
2963
2964<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]2965 &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]2966</pre>
2967
2968<h5>Overview:</h5>
2969
2970<p>
2971The '<tt>insertelement</tt>' instruction inserts a scalar
2972element into a vector at a specified index.
2973</p>
2974
2975
2976<h5>Arguments:</h5>
2977
2978<p>
2979The first operand of an '<tt>insertelement</tt>' instruction is a
2980value of <a href="#t_vector">vector</a> type. The second operand is a
2981scalar value whose type must equal the element type of the first
2982operand. The third operand is an index indicating the position at
2983which to insert the value. The index may be a variable.</p>
2984
2985<h5>Semantics:</h5>
2986
2987<p>
2988The result is a vector of the same type as <tt>val</tt>. Its
2989element values are those of <tt>val</tt> except at position
2990<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2991exceeds the length of <tt>val</tt>, the results are undefined.
2992</p>
2993
2994<h5>Example:</h5>
2995
2996<pre>
2997 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
2998</pre>
2999</div>
3000
3001<!-- _______________________________________________________________________ -->
3002<div class="doc_subsubsection">
3003 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3004</div>
3005
3006<div class="doc_text">
3007
3008<h5>Syntax:</h5>
3009
3010<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3011 &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]3012</pre>
3013
3014<h5>Overview:</h5>
3015
3016<p>
3017The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3018from two input vectors, returning a vector with the same element type as
3019the input and length that is the same as the shuffle mask.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3020</p>
3021
3022<h5>Arguments:</h5>
3023
3024<p>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3025The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3026with types that match each other. The third argument is a shuffle mask whose
3027element type is always 'i32'. The result of the instruction is a vector whose
3028length is the same as the shuffle mask and whose element type is the same as
3029the element type of the first two operands.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3030</p>
3031
3032<p>
3033The shuffle mask operand is required to be a constant vector with either
3034constant integer or undef values.
3035</p>
3036
3037<h5>Semantics:</h5>
3038
3039<p>
3040The elements of the two input vectors are numbered from left to right across
3041both of the vectors. The shuffle mask operand specifies, for each element of
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3042the result vector, which element of the two input vectors the result element
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3043gets. The element selector may be undef (meaning "don't care") and the second
3044operand may be undef if performing a shuffle from only one vector.
3045</p>
3046
3047<h5>Example:</h5>
3048
3049<pre>
3050 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3051 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3052 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3053 &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]3054 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3055 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3056 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3057 &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]3058</pre>
3059</div>
3060
3061
3062<!-- ======================================================================= -->
3063<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3064 <a name="aggregateops">Aggregate Operations</a>
3065</div>
3066
3067<div class="doc_text">
3068
3069<p>LLVM supports several instructions for working with aggregate values.
3070</p>
3071
3072</div>
3073
3074<!-- _______________________________________________________________________ -->
3075<div class="doc_subsubsection">
3076 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3077</div>
3078
3079<div class="doc_text">
3080
3081<h5>Syntax:</h5>
3082
3083<pre>
3084 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3085</pre>
3086
3087<h5>Overview:</h5>
3088
3089<p>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3090The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3091or array element from an aggregate value.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3092</p>
3093
3094
3095<h5>Arguments:</h5>
3096
3097<p>
3098The first operand of an '<tt>extractvalue</tt>' instruction is a
3099value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3100type. The operands are constant indices to specify which value to extract
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3101in a similar manner as indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3102'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3103</p>
3104
3105<h5>Semantics:</h5>
3106
3107<p>
3108The result is the value at the position in the aggregate specified by
3109the index operands.
3110</p>
3111
3112<h5>Example:</h5>
3113
3114<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3115 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3116</pre>
3117</div>
3118
3119
3120<!-- _______________________________________________________________________ -->
3121<div class="doc_subsubsection">
3122 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3123</div>
3124
3125<div class="doc_text">
3126
3127<h5>Syntax:</h5>
3128
3129<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3130 &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]3131</pre>
3132
3133<h5>Overview:</h5>
3134
3135<p>
3136The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3137into a struct field or array element in an aggregate.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3138</p>
3139
3140
3141<h5>Arguments:</h5>
3142
3143<p>
3144The first operand of an '<tt>insertvalue</tt>' instruction is a
3145value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
3146The second operand is a first-class value to insert.
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]3147The following operands are constant indices
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3148indicating the position at which to insert the value in a similar manner as
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3149indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3150'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3151The value to insert must have the same type as the value identified
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3152by the indices.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3153</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3154
3155<h5>Semantics:</h5>
3156
3157<p>
3158The result is an aggregate of the same type as <tt>val</tt>. Its
3159value is that of <tt>val</tt> except that the value at the position
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3160specified by the indices is that of <tt>elt</tt>.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3161</p>
3162
3163<h5>Example:</h5>
3164
3165<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3166 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3167</pre>
3168</div>
3169
3170
3171<!-- ======================================================================= -->
3172<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3173 <a name="memoryops">Memory Access and Addressing Operations</a>
3174</div>
3175
3176<div class="doc_text">
3177
3178<p>A key design point of an SSA-based representation is how it
3179represents memory. In LLVM, no memory locations are in SSA form, which
3180makes things very simple. This section describes how to read, write,
3181allocate, and free memory in LLVM.</p>
3182
3183</div>
3184
3185<!-- _______________________________________________________________________ -->
3186<div class="doc_subsubsection">
3187 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3188</div>
3189
3190<div class="doc_text">
3191
3192<h5>Syntax:</h5>
3193
3194<pre>
3195 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3196</pre>
3197
3198<h5>Overview:</h5>
3199
3200<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3201heap and returns a pointer to it. The object is always allocated in the generic
3202address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3203
3204<h5>Arguments:</h5>
3205
3206<p>The '<tt>malloc</tt>' instruction allocates
3207<tt>sizeof(&lt;type&gt;)*NumElements</tt>
3208bytes of memory from the operating system and returns a pointer of the
3209appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3210number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3211If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3212be aligned to at least that boundary. If not specified, or if zero, the target can
3213choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3214
3215<p>'<tt>type</tt>' must be a sized type.</p>
3216
3217<h5>Semantics:</h5>
3218
3219<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]3220a pointer is returned. The result of a zero byte allocation is undefined. The
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3221result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3222
3223<h5>Example:</h5>
3224
3225<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3226 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3227
3228 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3229 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3230 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3231 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3232 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3233</pre>
3234</div>
3235
3236<!-- _______________________________________________________________________ -->
3237<div class="doc_subsubsection">
3238 <a name="i_free">'<tt>free</tt>' Instruction</a>
3239</div>
3240
3241<div class="doc_text">
3242
3243<h5>Syntax:</h5>
3244
3245<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3246 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3247</pre>
3248
3249<h5>Overview:</h5>
3250
3251<p>The '<tt>free</tt>' instruction returns memory back to the unused
3252memory heap to be reallocated in the future.</p>
3253
3254<h5>Arguments:</h5>
3255
3256<p>'<tt>value</tt>' shall be a pointer value that points to a value
3257that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3258instruction.</p>
3259
3260<h5>Semantics:</h5>
3261
3262<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner329d6532008-04-19 22:41:32 +0000[diff] [blame]3263after this instruction executes. If the pointer is null, the operation
3264is a noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3265
3266<h5>Example:</h5>
3267
3268<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3269 %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]3270 free [4 x i8]* %array
3271</pre>
3272</div>
3273
3274<!-- _______________________________________________________________________ -->
3275<div class="doc_subsubsection">
3276 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3277</div>
3278
3279<div class="doc_text">
3280
3281<h5>Syntax:</h5>
3282
3283<pre>
3284 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3285</pre>
3286
3287<h5>Overview:</h5>
3288
3289<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3290currently executing function, to be automatically released when this function
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3291returns to its caller. The object is always allocated in the generic address
3292space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3293
3294<h5>Arguments:</h5>
3295
3296<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
3297bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3298appropriate type to the program. If "NumElements" is specified, it is the
3299number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3300If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3301to be aligned to at least that boundary. If not specified, or if zero, the target
3302can choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3303
3304<p>'<tt>type</tt>' may be any sized type.</p>
3305
3306<h5>Semantics:</h5>
3307
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3308<p>Memory is allocated; a pointer is returned. The operation is undefiend if
3309there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3310memory is automatically released when the function returns. The '<tt>alloca</tt>'
3311instruction is commonly used to represent automatic variables that must
3312have an address available. When the function returns (either with the <tt><a
3313 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]3314instructions), the memory is reclaimed. Allocating zero bytes
3315is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3316
3317<h5>Example:</h5>
3318
3319<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3320 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3321 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3322 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3323 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3324</pre>
3325</div>
3326
3327<!-- _______________________________________________________________________ -->
3328<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3329Instruction</a> </div>
3330<div class="doc_text">
3331<h5>Syntax:</h5>
3332<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>
3333<h5>Overview:</h5>
3334<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
3335<h5>Arguments:</h5>
3336<p>The argument to the '<tt>load</tt>' instruction specifies the memory
3337address from which to load. The pointer must point to a <a
3338 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3339marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
3340the number or order of execution of this <tt>load</tt> with other
3341volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3342instructions. </p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3343<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3344The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3345(that is, the alignment of the memory address). A value of 0 or an
3346omitted "align" argument means that the operation has the preferential
3347alignment for the target. It is the responsibility of the code emitter
3348to ensure that the alignment information is correct. Overestimating
3349the alignment results in an undefined behavior. Underestimating the
3350alignment may produce less efficient code. An alignment of 1 is always
3351safe.
3352</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3353<h5>Semantics:</h5>
3354<p>The location of memory pointed to is loaded.</p>
3355<h5>Examples:</h5>
3356<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3357 <a
3358 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3359 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3360</pre>
3361</div>
3362<!-- _______________________________________________________________________ -->
3363<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3364Instruction</a> </div>
3365<div class="doc_text">
3366<h5>Syntax:</h5>
3367<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3368 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3369</pre>
3370<h5>Overview:</h5>
3371<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
3372<h5>Arguments:</h5>
3373<p>There are two arguments to the '<tt>store</tt>' instruction: a value
3374to 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]3375operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3376of the '<tt>&lt;value&gt;</tt>'
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3377operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
3378optimizer is not allowed to modify the number or order of execution of
3379this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3380 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3381<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3382The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3383(that is, the alignment of the memory address). A value of 0 or an
3384omitted "align" argument means that the operation has the preferential
3385alignment for the target. It is the responsibility of the code emitter
3386to ensure that the alignment information is correct. Overestimating
3387the alignment results in an undefined behavior. Underestimating the
3388alignment may produce less efficient code. An alignment of 1 is always
3389safe.
3390</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3391<h5>Semantics:</h5>
3392<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
3393at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
3394<h5>Example:</h5>
3395<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3396 store i32 3, i32* %ptr <i>; yields {void}</i>
3397 %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]3398</pre>
3399</div>
3400
3401<!-- _______________________________________________________________________ -->
3402<div class="doc_subsubsection">
3403 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3404</div>
3405
3406<div class="doc_text">
3407<h5>Syntax:</h5>
3408<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3409 &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]3410</pre>
3411
3412<h5>Overview:</h5>
3413
3414<p>
3415The '<tt>getelementptr</tt>' instruction is used to get the address of a
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3416subelement of an aggregate data structure. It performs address calculation only
3417and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3418
3419<h5>Arguments:</h5>
3420
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3421<p>The first argument is always a pointer, and forms the basis of the
3422calculation. The remaining arguments are indices, that indicate which of the
3423elements of the aggregate object are indexed. The interpretation of each index
3424is dependent on the type being indexed into. The first index always indexes the
3425pointer value given as the first argument, the second index indexes a value of
3426the type pointed to (not necessarily the value directly pointed to, since the
3427first index can be non-zero), etc. The first type indexed into must be a pointer
3428value, subsequent types can be arrays, vectors and structs. Note that subsequent
3429types being indexed into can never be pointers, since that would require loading
3430the pointer before continuing calculation.</p>
3431
3432<p>The type of each index argument depends on the type it is indexing into.
3433When indexing into a (packed) structure, only <tt>i32</tt> integer
3434<b>constants</b> are allowed. When indexing into an array, pointer or vector,
3435only integers of 32 or 64 bits are allowed (also non-constants). 32-bit values
3436will be sign extended to 64-bits if required.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3437
3438<p>For example, let's consider a C code fragment and how it gets
3439compiled to LLVM:</p>
3440
3441<div class="doc_code">
3442<pre>
3443struct RT {
3444 char A;
3445 int B[10][20];
3446 char C;
3447};
3448struct ST {
3449 int X;
3450 double Y;
3451 struct RT Z;
3452};
3453
3454int *foo(struct ST *s) {
3455 return &amp;s[1].Z.B[5][13];
3456}
3457</pre>
3458</div>
3459
3460<p>The LLVM code generated by the GCC frontend is:</p>
3461
3462<div class="doc_code">
3463<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame^]3464%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
3465%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3466
3467define i32* %foo(%ST* %s) {
3468entry:
3469 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3470 ret i32* %reg
3471}
3472</pre>
3473</div>
3474
3475<h5>Semantics:</h5>
3476
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3477<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
3478type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3479}</tt>' type, a structure. The second index indexes into the third element of
3480the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3481i8 }</tt>' type, another structure. The third index indexes into the second
3482element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3483array. The two dimensions of the array are subscripted into, yielding an
3484'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3485to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
3486
3487<p>Note that it is perfectly legal to index partially through a
3488structure, returning a pointer to an inner element. Because of this,
3489the LLVM code for the given testcase is equivalent to:</p>
3490
3491<pre>
3492 define i32* %foo(%ST* %s) {
3493 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3494 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3495 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3496 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3497 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3498 ret i32* %t5
3499 }
3500</pre>
3501
3502<p>Note that it is undefined to access an array out of bounds: array and
3503pointer indexes must always be within the defined bounds of the array type.
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]3504The one exception for this rule is zero length arrays. These arrays are
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3505defined to be accessible as variable length arrays, which requires access
3506beyond the zero'th element.</p>
3507
3508<p>The getelementptr instruction is often confusing. For some more insight
3509into how it works, see <a href="GetElementPtr.html">the getelementptr
3510FAQ</a>.</p>
3511
3512<h5>Example:</h5>
3513
3514<pre>
3515 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3516 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3517 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3518 %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]3519 <i>; yields i8*:eptr</i>
3520 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3521</pre>
3522</div>
3523
3524<!-- ======================================================================= -->
3525<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3526</div>
3527<div class="doc_text">
3528<p>The instructions in this category are the conversion instructions (casting)
3529which all take a single operand and a type. They perform various bit conversions
3530on the operand.</p>
3531</div>
3532
3533<!-- _______________________________________________________________________ -->
3534<div class="doc_subsubsection">
3535 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3536</div>
3537<div class="doc_text">
3538
3539<h5>Syntax:</h5>
3540<pre>
3541 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3542</pre>
3543
3544<h5>Overview:</h5>
3545<p>
3546The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3547</p>
3548
3549<h5>Arguments:</h5>
3550<p>
3551The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3552be an <a href="#t_integer">integer</a> type, and a type that specifies the size
3553and type of the result, which must be an <a href="#t_integer">integer</a>
3554type. The bit size of <tt>value</tt> must be larger than the bit size of
3555<tt>ty2</tt>. Equal sized types are not allowed.</p>
3556
3557<h5>Semantics:</h5>
3558<p>
3559The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
3560and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3561larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3562It will always truncate bits.</p>
3563
3564<h5>Example:</h5>
3565<pre>
3566 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3567 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3568 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
3569</pre>
3570</div>
3571
3572<!-- _______________________________________________________________________ -->
3573<div class="doc_subsubsection">
3574 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3575</div>
3576<div class="doc_text">
3577
3578<h5>Syntax:</h5>
3579<pre>
3580 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3581</pre>
3582
3583<h5>Overview:</h5>
3584<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3585<tt>ty2</tt>.</p>
3586
3587
3588<h5>Arguments:</h5>
3589<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
3590<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3591also be of <a href="#t_integer">integer</a> type. The bit size of the
3592<tt>value</tt> must be smaller than the bit size of the destination type,
3593<tt>ty2</tt>.</p>
3594
3595<h5>Semantics:</h5>
3596<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
3597bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
3598
3599<p>When zero extending from i1, the result will always be either 0 or 1.</p>
3600
3601<h5>Example:</h5>
3602<pre>
3603 %X = zext i32 257 to i64 <i>; yields i64:257</i>
3604 %Y = zext i1 true to i32 <i>; yields i32:1</i>
3605</pre>
3606</div>
3607
3608<!-- _______________________________________________________________________ -->
3609<div class="doc_subsubsection">
3610 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3611</div>
3612<div class="doc_text">
3613
3614<h5>Syntax:</h5>
3615<pre>
3616 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3617</pre>
3618
3619<h5>Overview:</h5>
3620<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3621
3622<h5>Arguments:</h5>
3623<p>
3624The '<tt>sext</tt>' instruction takes a value to cast, which must be of
3625<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3626also be of <a href="#t_integer">integer</a> type. The bit size of the
3627<tt>value</tt> must be smaller than the bit size of the destination type,
3628<tt>ty2</tt>.</p>
3629
3630<h5>Semantics:</h5>
3631<p>
3632The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3633bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
3634the type <tt>ty2</tt>.</p>
3635
3636<p>When sign extending from i1, the extension always results in -1 or 0.</p>
3637
3638<h5>Example:</h5>
3639<pre>
3640 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
3641 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
3642</pre>
3643</div>
3644
3645<!-- _______________________________________________________________________ -->
3646<div class="doc_subsubsection">
3647 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3648</div>
3649
3650<div class="doc_text">
3651
3652<h5>Syntax:</h5>
3653
3654<pre>
3655 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3656</pre>
3657
3658<h5>Overview:</h5>
3659<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3660<tt>ty2</tt>.</p>
3661
3662
3663<h5>Arguments:</h5>
3664<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3665 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3666cast it to. The size of <tt>value</tt> must be larger than the size of
3667<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3668<i>no-op cast</i>.</p>
3669
3670<h5>Semantics:</h5>
3671<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3672<a href="#t_floating">floating point</a> type to a smaller
3673<a href="#t_floating">floating point</a> type. If the value cannot fit within
3674the destination type, <tt>ty2</tt>, then the results are undefined.</p>
3675
3676<h5>Example:</h5>
3677<pre>
3678 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3679 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3680</pre>
3681</div>
3682
3683<!-- _______________________________________________________________________ -->
3684<div class="doc_subsubsection">
3685 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3686</div>
3687<div class="doc_text">
3688
3689<h5>Syntax:</h5>
3690<pre>
3691 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3692</pre>
3693
3694<h5>Overview:</h5>
3695<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3696floating point value.</p>
3697
3698<h5>Arguments:</h5>
3699<p>The '<tt>fpext</tt>' instruction takes a
3700<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
3701and a <a href="#t_floating">floating point</a> type to cast it to. The source
3702type must be smaller than the destination type.</p>
3703
3704<h5>Semantics:</h5>
3705<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
3706<a href="#t_floating">floating point</a> type to a larger
3707<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
3708used to make a <i>no-op cast</i> because it always changes bits. Use
3709<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
3710
3711<h5>Example:</h5>
3712<pre>
3713 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3714 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3715</pre>
3716</div>
3717
3718<!-- _______________________________________________________________________ -->
3719<div class="doc_subsubsection">
3720 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
3721</div>
3722<div class="doc_text">
3723
3724<h5>Syntax:</h5>
3725<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3726 &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]3727</pre>
3728
3729<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3730<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3731unsigned integer equivalent of type <tt>ty2</tt>.
3732</p>
3733
3734<h5>Arguments:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3735<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]3736scalar or vector <a href="#t_floating">floating point</a> value, and a type
3737to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3738type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3739vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3740
3741<h5>Semantics:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3742<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3743<a href="#t_floating">floating point</a> operand into the nearest (rounding
3744towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3745the results are undefined.</p>
3746
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3747<h5>Example:</h5>
3748<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3749 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3750 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3751 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3752</pre>
3753</div>
3754
3755<!-- _______________________________________________________________________ -->
3756<div class="doc_subsubsection">
3757 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
3758</div>
3759<div class="doc_text">
3760
3761<h5>Syntax:</h5>
3762<pre>
3763 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3764</pre>
3765
3766<h5>Overview:</h5>
3767<p>The '<tt>fptosi</tt>' instruction converts
3768<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
3769</p>
3770
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3771<h5>Arguments:</h5>
3772<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]3773scalar or vector <a href="#t_floating">floating point</a> value, and a type
3774to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3775type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3776vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3777
3778<h5>Semantics:</h5>
3779<p>The '<tt>fptosi</tt>' instruction converts its
3780<a href="#t_floating">floating point</a> operand into the nearest (rounding
3781towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3782the results are undefined.</p>
3783
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3784<h5>Example:</h5>
3785<pre>
3786 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3787 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3788 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
3789</pre>
3790</div>
3791
3792<!-- _______________________________________________________________________ -->
3793<div class="doc_subsubsection">
3794 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
3795</div>
3796<div class="doc_text">
3797
3798<h5>Syntax:</h5>
3799<pre>
3800 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3801</pre>
3802
3803<h5>Overview:</h5>
3804<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
3805integer and converts that value to the <tt>ty2</tt> type.</p>
3806
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3807<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3808<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3809scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3810to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3811type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3812floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3813
3814<h5>Semantics:</h5>
3815<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
3816integer quantity and converts it to the corresponding floating point value. If
3817the value cannot fit in the floating point value, the results are undefined.</p>
3818
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3819<h5>Example:</h5>
3820<pre>
3821 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3822 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3823</pre>
3824</div>
3825
3826<!-- _______________________________________________________________________ -->
3827<div class="doc_subsubsection">
3828 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
3829</div>
3830<div class="doc_text">
3831
3832<h5>Syntax:</h5>
3833<pre>
3834 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3835</pre>
3836
3837<h5>Overview:</h5>
3838<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
3839integer and converts that value to the <tt>ty2</tt> type.</p>
3840
3841<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3842<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3843scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3844to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3845type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3846floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3847
3848<h5>Semantics:</h5>
3849<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
3850integer quantity and converts it to the corresponding floating point value. If
3851the value cannot fit in the floating point value, the results are undefined.</p>
3852
3853<h5>Example:</h5>
3854<pre>
3855 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3856 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3857</pre>
3858</div>
3859
3860<!-- _______________________________________________________________________ -->
3861<div class="doc_subsubsection">
3862 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3863</div>
3864<div class="doc_text">
3865
3866<h5>Syntax:</h5>
3867<pre>
3868 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3869</pre>
3870
3871<h5>Overview:</h5>
3872<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3873the integer type <tt>ty2</tt>.</p>
3874
3875<h5>Arguments:</h5>
3876<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3877must 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]3878<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]3879
3880<h5>Semantics:</h5>
3881<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3882<tt>ty2</tt> by interpreting the pointer value as an integer and either
3883truncating or zero extending that value to the size of the integer type. If
3884<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3885<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3886are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3887change.</p>
3888
3889<h5>Example:</h5>
3890<pre>
3891 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3892 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
3893</pre>
3894</div>
3895
3896<!-- _______________________________________________________________________ -->
3897<div class="doc_subsubsection">
3898 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3899</div>
3900<div class="doc_text">
3901
3902<h5>Syntax:</h5>
3903<pre>
3904 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3905</pre>
3906
3907<h5>Overview:</h5>
3908<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3909a pointer type, <tt>ty2</tt>.</p>
3910
3911<h5>Arguments:</h5>
3912<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
3913value to cast, and a type to cast it to, which must be a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3914<a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3915
3916<h5>Semantics:</h5>
3917<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3918<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3919the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3920size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3921the size of a pointer then a zero extension is done. If they are the same size,
3922nothing is done (<i>no-op cast</i>).</p>
3923
3924<h5>Example:</h5>
3925<pre>
3926 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3927 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3928 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
3929</pre>
3930</div>
3931
3932<!-- _______________________________________________________________________ -->
3933<div class="doc_subsubsection">
3934 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
3935</div>
3936<div class="doc_text">
3937
3938<h5>Syntax:</h5>
3939<pre>
3940 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3941</pre>
3942
3943<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3944
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3945<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
3946<tt>ty2</tt> without changing any bits.</p>
3947
3948<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3949
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3950<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Dan Gohman7305fa02008-09-08 16:45:59 +0000[diff] [blame]3951a non-aggregate first class value, and a type to cast it to, which must also be
3952a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
3953<tt>value</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3954and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3955type is a pointer, the destination type must also be a pointer. This
3956instruction supports bitwise conversion of vectors to integers and to vectors
3957of other types (as long as they have the same size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3958
3959<h5>Semantics:</h5>
3960<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
3961<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3962this conversion. The conversion is done as if the <tt>value</tt> had been
3963stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3964converted to other pointer types with this instruction. To convert pointers to
3965other types, use the <a href="#i_inttoptr">inttoptr</a> or
3966<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
3967
3968<h5>Example:</h5>
3969<pre>
3970 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
3971 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3972 %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]3973</pre>
3974</div>
3975
3976<!-- ======================================================================= -->
3977<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3978<div class="doc_text">
3979<p>The instructions in this category are the "miscellaneous"
3980instructions, which defy better classification.</p>
3981</div>
3982
3983<!-- _______________________________________________________________________ -->
3984<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3985</div>
3986<div class="doc_text">
3987<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3988<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]3989</pre>
3990<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]3991<p>The '<tt>icmp</tt>' instruction returns a boolean value or
3992a vector of boolean values based on comparison
3993of its two integer, integer vector, or pointer operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3994<h5>Arguments:</h5>
3995<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
3996the condition code indicating the kind of comparison to perform. It is not
3997a value, just a keyword. The possible condition code are:
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3998</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3999<ol>
4000 <li><tt>eq</tt>: equal</li>
4001 <li><tt>ne</tt>: not equal </li>
4002 <li><tt>ugt</tt>: unsigned greater than</li>
4003 <li><tt>uge</tt>: unsigned greater or equal</li>
4004 <li><tt>ult</tt>: unsigned less than</li>
4005 <li><tt>ule</tt>: unsigned less or equal</li>
4006 <li><tt>sgt</tt>: signed greater than</li>
4007 <li><tt>sge</tt>: signed greater or equal</li>
4008 <li><tt>slt</tt>: signed less than</li>
4009 <li><tt>sle</tt>: signed less or equal</li>
4010</ol>
4011<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4012<a href="#t_pointer">pointer</a>
4013or integer <a href="#t_vector">vector</a> typed.
4014They must also be identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4015<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4016<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]4017the condition code given as <tt>cond</tt>. The comparison performed always
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4018yields 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]4019</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4020<ol>
4021 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
4022 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
4023 </li>
4024 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4025 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4026 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4027 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4028 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4029 <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]4030 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4031 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4032 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4033 <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]4034 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4035 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4036 <li><tt>sge</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4037 <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]4038 <li><tt>slt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4039 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4040 <li><tt>sle</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4041 <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]4042</ol>
4043<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
4044values are compared as if they were integers.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4045<p>If the operands are integer vectors, then they are compared
4046element by element. The result is an <tt>i1</tt> vector with
4047the same number of elements as the values being compared.
4048Otherwise, the result is an <tt>i1</tt>.
4049</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4050
4051<h5>Example:</h5>
4052<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
4053 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4054 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4055 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4056 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4057 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4058</pre>
4059</div>
4060
4061<!-- _______________________________________________________________________ -->
4062<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4063</div>
4064<div class="doc_text">
4065<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4066<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]4067</pre>
4068<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4069<p>The '<tt>fcmp</tt>' instruction returns a boolean value
4070or vector of boolean values based on comparison
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4071of its operands.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4072<p>
4073If the operands are floating point scalars, then the result
4074type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
4075</p>
4076<p>If the operands are floating point vectors, then the result type
4077is a vector of boolean with the same number of elements as the
4078operands being compared.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4079<h5>Arguments:</h5>
4080<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
4081the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4082a value, just a keyword. The possible condition code are:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4083<ol>
4084 <li><tt>false</tt>: no comparison, always returns false</li>
4085 <li><tt>oeq</tt>: ordered and equal</li>
4086 <li><tt>ogt</tt>: ordered and greater than </li>
4087 <li><tt>oge</tt>: ordered and greater than or equal</li>
4088 <li><tt>olt</tt>: ordered and less than </li>
4089 <li><tt>ole</tt>: ordered and less than or equal</li>
4090 <li><tt>one</tt>: ordered and not equal</li>
4091 <li><tt>ord</tt>: ordered (no nans)</li>
4092 <li><tt>ueq</tt>: unordered or equal</li>
4093 <li><tt>ugt</tt>: unordered or greater than </li>
4094 <li><tt>uge</tt>: unordered or greater than or equal</li>
4095 <li><tt>ult</tt>: unordered or less than </li>
4096 <li><tt>ule</tt>: unordered or less than or equal</li>
4097 <li><tt>une</tt>: unordered or not equal</li>
4098 <li><tt>uno</tt>: unordered (either nans)</li>
4099 <li><tt>true</tt>: no comparison, always returns true</li>
4100</ol>
4101<p><i>Ordered</i> means that neither operand is a QNAN while
4102<i>unordered</i> means that either operand may be a QNAN.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4103<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
4104either a <a href="#t_floating">floating point</a> type
4105or a <a href="#t_vector">vector</a> of floating point type.
4106They must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4107<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4108<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4109according to the condition code given as <tt>cond</tt>.
4110If the operands are vectors, then the vectors are compared
4111element by element.
4112Each comparison performed
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4113always yields an <a href="#t_primitive">i1</a> result, as follows:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4114<ol>
4115 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
4116 <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]4117 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4118 <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]4119 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4120 <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]4121 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4122 <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]4123 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4124 <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]4125 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4126 <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]4127 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4128 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
4129 <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]4130 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4131 <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]4132 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4133 <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]4134 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4135 <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]4136 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4137 <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]4138 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4139 <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]4140 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4141 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
4142 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4143</ol>
4144
4145<h5>Example:</h5>
4146<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]4147 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4148 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4149 &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]4150</pre>
4151</div>
4152
4153<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4154<div class="doc_subsubsection">
4155 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
4156</div>
4157<div class="doc_text">
4158<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4159<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]4160</pre>
4161<h5>Overview:</h5>
4162<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
4163element-wise comparison of its two integer vector operands.</p>
4164<h5>Arguments:</h5>
4165<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
4166the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4167a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4168<ol>
4169 <li><tt>eq</tt>: equal</li>
4170 <li><tt>ne</tt>: not equal </li>
4171 <li><tt>ugt</tt>: unsigned greater than</li>
4172 <li><tt>uge</tt>: unsigned greater or equal</li>
4173 <li><tt>ult</tt>: unsigned less than</li>
4174 <li><tt>ule</tt>: unsigned less or equal</li>
4175 <li><tt>sgt</tt>: signed greater than</li>
4176 <li><tt>sge</tt>: signed greater or equal</li>
4177 <li><tt>slt</tt>: signed less than</li>
4178 <li><tt>sle</tt>: signed less or equal</li>
4179</ol>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4180<p>The remaining two arguments must be <a href="#t_vector">vector</a> or
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4181<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
4182<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4183<p>The '<tt>vicmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4184according to the condition code given as <tt>cond</tt>. The comparison yields a
4185<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
4186identical type as the values being compared. The most significant bit in each
4187element is 1 if the element-wise comparison evaluates to true, and is 0
4188otherwise. All other bits of the result are undefined. The condition codes
4189are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4190instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4191
4192<h5>Example:</h5>
4193<pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4194 &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>
4195 &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]4196</pre>
4197</div>
4198
4199<!-- _______________________________________________________________________ -->
4200<div class="doc_subsubsection">
4201 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
4202</div>
4203<div class="doc_text">
4204<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4205<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]4206<h5>Overview:</h5>
4207<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
4208element-wise comparison of its two floating point vector operands. The output
4209elements have the same width as the input elements.</p>
4210<h5>Arguments:</h5>
4211<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
4212the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4213a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4214<ol>
4215 <li><tt>false</tt>: no comparison, always returns false</li>
4216 <li><tt>oeq</tt>: ordered and equal</li>
4217 <li><tt>ogt</tt>: ordered and greater than </li>
4218 <li><tt>oge</tt>: ordered and greater than or equal</li>
4219 <li><tt>olt</tt>: ordered and less than </li>
4220 <li><tt>ole</tt>: ordered and less than or equal</li>
4221 <li><tt>one</tt>: ordered and not equal</li>
4222 <li><tt>ord</tt>: ordered (no nans)</li>
4223 <li><tt>ueq</tt>: unordered or equal</li>
4224 <li><tt>ugt</tt>: unordered or greater than </li>
4225 <li><tt>uge</tt>: unordered or greater than or equal</li>
4226 <li><tt>ult</tt>: unordered or less than </li>
4227 <li><tt>ule</tt>: unordered or less than or equal</li>
4228 <li><tt>une</tt>: unordered or not equal</li>
4229 <li><tt>uno</tt>: unordered (either nans)</li>
4230 <li><tt>true</tt>: no comparison, always returns true</li>
4231</ol>
4232<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4233<a href="#t_floating">floating point</a> typed. They must also be identical
4234types.</p>
4235<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4236<p>The '<tt>vfcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4237according to the condition code given as <tt>cond</tt>. The comparison yields a
4238<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4239an identical number of elements as the values being compared, and each element
4240having identical with to the width of the floating point elements. The most
4241significant bit in each element is 1 if the element-wise comparison evaluates to
4242true, and is 0 otherwise. All other bits of the result are undefined. The
4243condition codes are evaluated identically to the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4244<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4245
4246<h5>Example:</h5>
4247<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]4248 <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4249 &lt;result&gt; = vfcmp oeq &lt;2 x float&gt; &lt; float 4, float 0 &gt;, &lt; float 5, float 0 &gt;
4250
4251 <i>; yields: result=&lt;2 x i64&gt; &lt; i64 -1, i64 0 &gt;</i>
4252 &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]4253</pre>
4254</div>
4255
4256<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4257<div class="doc_subsubsection">
4258 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4259</div>
4260
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4261<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4262
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4263<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4264
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4265<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4266<h5>Overview:</h5>
4267<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4268the SSA graph representing the function.</p>
4269<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4270
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4271<p>The type of the incoming values is specified with the first type
4272field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4273as arguments, with one pair for each predecessor basic block of the
4274current block. Only values of <a href="#t_firstclass">first class</a>
4275type may be used as the value arguments to the PHI node. Only labels
4276may be used as the label arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4277
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4278<p>There must be no non-phi instructions between the start of a basic
4279block and the PHI instructions: i.e. PHI instructions must be first in
4280a basic block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4281
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4282<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4283
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4284<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4285specified by the pair corresponding to the predecessor basic block that executed
4286just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4287
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4288<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4289<pre>
4290Loop: ; Infinite loop that counts from 0 on up...
4291 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4292 %nextindvar = add i32 %indvar, 1
4293 br label %Loop
4294</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4295</div>
4296
4297<!-- _______________________________________________________________________ -->
4298<div class="doc_subsubsection">
4299 <a name="i_select">'<tt>select</tt>' Instruction</a>
4300</div>
4301
4302<div class="doc_text">
4303
4304<h5>Syntax:</h5>
4305
4306<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4307 &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>
4308
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4309 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4310</pre>
4311
4312<h5>Overview:</h5>
4313
4314<p>
4315The '<tt>select</tt>' instruction is used to choose one value based on a
4316condition, without branching.
4317</p>
4318
4319
4320<h5>Arguments:</h5>
4321
4322<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4323The '<tt>select</tt>' instruction requires an 'i1' value or
4324a vector of 'i1' values indicating the
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4325condition, and two values of the same <a href="#t_firstclass">first class</a>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4326type. If the val1/val2 are vectors and
4327the condition is a scalar, then entire vectors are selected, not
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4328individual elements.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4329</p>
4330
4331<h5>Semantics:</h5>
4332
4333<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4334If 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]4335value argument; otherwise, it returns the second value argument.
4336</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4337<p>
4338If the condition is a vector of i1, then the value arguments must
4339be vectors of the same size, and the selection is done element
4340by element.
4341</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4342
4343<h5>Example:</h5>
4344
4345<pre>
4346 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4347</pre>
4348</div>
4349
4350
4351<!-- _______________________________________________________________________ -->
4352<div class="doc_subsubsection">
4353 <a name="i_call">'<tt>call</tt>' Instruction</a>
4354</div>
4355
4356<div class="doc_text">
4357
4358<h5>Syntax:</h5>
4359<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4360 &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]4361</pre>
4362
4363<h5>Overview:</h5>
4364
4365<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4366
4367<h5>Arguments:</h5>
4368
4369<p>This instruction requires several arguments:</p>
4370
4371<ol>
4372 <li>
4373 <p>The optional "tail" marker indicates whether the callee function accesses
4374 any allocas or varargs in the caller. If the "tail" marker is present, the
4375 function call is eligible for tail call optimization. Note that calls may
4376 be marked "tail" even if they do not occur before a <a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4377 href="#i_ret"><tt>ret</tt></a> instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4378 </li>
4379 <li>
4380 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
4381 convention</a> the call should use. If none is specified, the call defaults
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4382 to using C calling conventions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4383 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4384
4385 <li>
4386 <p>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4387 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
4388 and '<tt>inreg</tt>' attributes are valid here.</p>
4389 </li>
4390
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4391 <li>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4392 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4393 the type of the return value. Functions that return no value are marked
4394 <tt><a href="#t_void">void</a></tt>.</p>
4395 </li>
4396 <li>
4397 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4398 value being invoked. The argument types must match the types implied by
4399 this signature. This type can be omitted if the function is not varargs
4400 and if the function type does not return a pointer to a function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4401 </li>
4402 <li>
4403 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4404 be invoked. In most cases, this is a direct function invocation, but
4405 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4406 to function value.</p>
4407 </li>
4408 <li>
4409 <p>'<tt>function args</tt>': argument list whose types match the
4410 function signature argument types. All arguments must be of
4411 <a href="#t_firstclass">first class</a> type. If the function signature
4412 indicates the function accepts a variable number of arguments, the extra
4413 arguments can be specified.</p>
4414 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4415 <li>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4416 <p>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4417 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4418 '<tt>readnone</tt>' attributes are valid here.</p>
4419 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4420</ol>
4421
4422<h5>Semantics:</h5>
4423
4424<p>The '<tt>call</tt>' instruction is used to cause control flow to
4425transfer to a specified function, with its incoming arguments bound to
4426the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4427instruction in the called function, control flow continues with the
4428instruction after the function call, and the return value of the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4429function is bound to the result argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4430
4431<h5>Example:</h5>
4432
4433<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4434 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4435 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4436 %X = tail call i32 @foo() <i>; yields i32</i>
4437 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4438 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4439
4440 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4441 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]4442 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4443 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]4444 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]4445 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4446</pre>
4447
4448</div>
4449
4450<!-- _______________________________________________________________________ -->
4451<div class="doc_subsubsection">
4452 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4453</div>
4454
4455<div class="doc_text">
4456
4457<h5>Syntax:</h5>
4458
4459<pre>
4460 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4461</pre>
4462
4463<h5>Overview:</h5>
4464
4465<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
4466the "variable argument" area of a function call. It is used to implement the
4467<tt>va_arg</tt> macro in C.</p>
4468
4469<h5>Arguments:</h5>
4470
4471<p>This instruction takes a <tt>va_list*</tt> value and the type of
4472the argument. It returns a value of the specified argument type and
4473increments the <tt>va_list</tt> to point to the next argument. The
4474actual type of <tt>va_list</tt> is target specific.</p>
4475
4476<h5>Semantics:</h5>
4477
4478<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4479type from the specified <tt>va_list</tt> and causes the
4480<tt>va_list</tt> to point to the next argument. For more information,
4481see the variable argument handling <a href="#int_varargs">Intrinsic
4482Functions</a>.</p>
4483
4484<p>It is legal for this instruction to be called in a function which does not
4485take a variable number of arguments, for example, the <tt>vfprintf</tt>
4486function.</p>
4487
4488<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
4489href="#intrinsics">intrinsic function</a> because it takes a type as an
4490argument.</p>
4491
4492<h5>Example:</h5>
4493
4494<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4495
4496</div>
4497
4498<!-- *********************************************************************** -->
4499<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4500<!-- *********************************************************************** -->
4501
4502<div class="doc_text">
4503
4504<p>LLVM supports the notion of an "intrinsic function". These functions have
4505well known names and semantics and are required to follow certain restrictions.
4506Overall, these intrinsics represent an extension mechanism for the LLVM
4507language that does not require changing all of the transformations in LLVM when
4508adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
4509
4510<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
4511prefix is reserved in LLVM for intrinsic names; thus, function names may not
4512begin with this prefix. Intrinsic functions must always be external functions:
4513you cannot define the body of intrinsic functions. Intrinsic functions may
4514only be used in call or invoke instructions: it is illegal to take the address
4515of an intrinsic function. Additionally, because intrinsic functions are part
4516of the LLVM language, it is required if any are added that they be documented
4517here.</p>
4518
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4519<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4520a family of functions that perform the same operation but on different data
4521types. Because LLVM can represent over 8 million different integer types,
4522overloading is used commonly to allow an intrinsic function to operate on any
4523integer type. One or more of the argument types or the result type can be
4524overloaded to accept any integer type. Argument types may also be defined as
4525exactly matching a previous argument's type or the result type. This allows an
4526intrinsic function which accepts multiple arguments, but needs all of them to
4527be of the same type, to only be overloaded with respect to a single argument or
4528the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4529
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4530<p>Overloaded intrinsics will have the names of its overloaded argument types
4531encoded into its function name, each preceded by a period. Only those types
4532which are overloaded result in a name suffix. Arguments whose type is matched
4533against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4534take an integer of any width and returns an integer of exactly the same integer
4535width. This leads to a family of functions such as
4536<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4537Only one type, the return type, is overloaded, and only one type suffix is
4538required. Because the argument's type is matched against the return type, it
4539does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4540
4541<p>To learn how to add an intrinsic function, please see the
4542<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
4543</p>
4544
4545</div>
4546
4547<!-- ======================================================================= -->
4548<div class="doc_subsection">
4549 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4550</div>
4551
4552<div class="doc_text">
4553
4554<p>Variable argument support is defined in LLVM with the <a
4555 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4556intrinsic functions. These functions are related to the similarly
4557named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
4558
4559<p>All of these functions operate on arguments that use a
4560target-specific value type "<tt>va_list</tt>". The LLVM assembly
4561language reference manual does not define what this type is, so all
4562transformations should be prepared to handle these functions regardless of
4563the type used.</p>
4564
4565<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
4566instruction and the variable argument handling intrinsic functions are
4567used.</p>
4568
4569<div class="doc_code">
4570<pre>
4571define i32 @test(i32 %X, ...) {
4572 ; Initialize variable argument processing
4573 %ap = alloca i8*
4574 %ap2 = bitcast i8** %ap to i8*
4575 call void @llvm.va_start(i8* %ap2)
4576
4577 ; Read a single integer argument
4578 %tmp = va_arg i8** %ap, i32
4579
4580 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4581 %aq = alloca i8*
4582 %aq2 = bitcast i8** %aq to i8*
4583 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4584 call void @llvm.va_end(i8* %aq2)
4585
4586 ; Stop processing of arguments.
4587 call void @llvm.va_end(i8* %ap2)
4588 ret i32 %tmp
4589}
4590
4591declare void @llvm.va_start(i8*)
4592declare void @llvm.va_copy(i8*, i8*)
4593declare void @llvm.va_end(i8*)
4594</pre>
4595</div>
4596
4597</div>
4598
4599<!-- _______________________________________________________________________ -->
4600<div class="doc_subsubsection">
4601 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4602</div>
4603
4604
4605<div class="doc_text">
4606<h5>Syntax:</h5>
4607<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
4608<h5>Overview:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4609<p>The '<tt>llvm.va_start</tt>' intrinsic initializes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4610<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4611href="#i_va_arg">va_arg</a></tt>.</p>
4612
4613<h5>Arguments:</h5>
4614
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4615<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]4616
4617<h5>Semantics:</h5>
4618
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4619<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]4620macro available in C. In a target-dependent way, it initializes the
4621<tt>va_list</tt> element to which the argument points, so that the next call to
4622<tt>va_arg</tt> will produce the first variable argument passed to the function.
4623Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
4624last argument of the function as the compiler can figure that out.</p>
4625
4626</div>
4627
4628<!-- _______________________________________________________________________ -->
4629<div class="doc_subsubsection">
4630 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
4631</div>
4632
4633<div class="doc_text">
4634<h5>Syntax:</h5>
4635<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
4636<h5>Overview:</h5>
4637
4638<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
4639which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
4640or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
4641
4642<h5>Arguments:</h5>
4643
4644<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
4645
4646<h5>Semantics:</h5>
4647
4648<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
4649macro available in C. In a target-dependent way, it destroys the
4650<tt>va_list</tt> element to which the argument points. Calls to <a
4651href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4652<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4653<tt>llvm.va_end</tt>.</p>
4654
4655</div>
4656
4657<!-- _______________________________________________________________________ -->
4658<div class="doc_subsubsection">
4659 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
4660</div>
4661
4662<div class="doc_text">
4663
4664<h5>Syntax:</h5>
4665
4666<pre>
4667 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
4668</pre>
4669
4670<h5>Overview:</h5>
4671
4672<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4673from the source argument list to the destination argument list.</p>
4674
4675<h5>Arguments:</h5>
4676
4677<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
4678The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
4679
4680
4681<h5>Semantics:</h5>
4682
4683<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4684macro available in C. In a target-dependent way, it copies the source
4685<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4686intrinsic is necessary because the <tt><a href="#int_va_start">
4687llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4688example, memory allocation.</p>
4689
4690</div>
4691
4692<!-- ======================================================================= -->
4693<div class="doc_subsection">
4694 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4695</div>
4696
4697<div class="doc_text">
4698
4699<p>
4700LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]4701Collection</a> (GC) requires the implementation and generation of these
4702intrinsics.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4703These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
4704stack</a>, as well as garbage collector implementations that require <a
4705href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
4706Front-ends for type-safe garbage collected languages should generate these
4707intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4708href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4709</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]4710
4711<p>The garbage collection intrinsics only operate on objects in the generic
4712 address space (address space zero).</p>
4713
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4714</div>
4715
4716<!-- _______________________________________________________________________ -->
4717<div class="doc_subsubsection">
4718 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
4719</div>
4720
4721<div class="doc_text">
4722
4723<h5>Syntax:</h5>
4724
4725<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4726 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4727</pre>
4728
4729<h5>Overview:</h5>
4730
4731<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
4732the code generator, and allows some metadata to be associated with it.</p>
4733
4734<h5>Arguments:</h5>
4735
4736<p>The first argument specifies the address of a stack object that contains the
4737root pointer. The second pointer (which must be either a constant or a global
4738value address) contains the meta-data to be associated with the root.</p>
4739
4740<h5>Semantics:</h5>
4741
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]4742<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]4743location. At compile-time, the code generator generates information to allow
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4744the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4745intrinsic may only be used in a function which <a href="#gc">specifies a GC
4746algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4747
4748</div>
4749
4750
4751<!-- _______________________________________________________________________ -->
4752<div class="doc_subsubsection">
4753 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
4754</div>
4755
4756<div class="doc_text">
4757
4758<h5>Syntax:</h5>
4759
4760<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4761 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4762</pre>
4763
4764<h5>Overview:</h5>
4765
4766<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4767locations, allowing garbage collector implementations that require read
4768barriers.</p>
4769
4770<h5>Arguments:</h5>
4771
4772<p>The second argument is the address to read from, which should be an address
4773allocated from the garbage collector. The first object is a pointer to the
4774start of the referenced object, if needed by the language runtime (otherwise
4775null).</p>
4776
4777<h5>Semantics:</h5>
4778
4779<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4780instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4781garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4782may only be used in a function which <a href="#gc">specifies a GC
4783algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4784
4785</div>
4786
4787
4788<!-- _______________________________________________________________________ -->
4789<div class="doc_subsubsection">
4790 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
4791</div>
4792
4793<div class="doc_text">
4794
4795<h5>Syntax:</h5>
4796
4797<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4798 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4799</pre>
4800
4801<h5>Overview:</h5>
4802
4803<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4804locations, allowing garbage collector implementations that require write
4805barriers (such as generational or reference counting collectors).</p>
4806
4807<h5>Arguments:</h5>
4808
4809<p>The first argument is the reference to store, the second is the start of the
4810object to store it to, and the third is the address of the field of Obj to
4811store to. If the runtime does not require a pointer to the object, Obj may be
4812null.</p>
4813
4814<h5>Semantics:</h5>
4815
4816<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4817instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4818garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4819may only be used in a function which <a href="#gc">specifies a GC
4820algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4821
4822</div>
4823
4824
4825
4826<!-- ======================================================================= -->
4827<div class="doc_subsection">
4828 <a name="int_codegen">Code Generator Intrinsics</a>
4829</div>
4830
4831<div class="doc_text">
4832<p>
4833These intrinsics are provided by LLVM to expose special features that may only
4834be implemented with code generator support.
4835</p>
4836
4837</div>
4838
4839<!-- _______________________________________________________________________ -->
4840<div class="doc_subsubsection">
4841 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
4842</div>
4843
4844<div class="doc_text">
4845
4846<h5>Syntax:</h5>
4847<pre>
4848 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
4849</pre>
4850
4851<h5>Overview:</h5>
4852
4853<p>
4854The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4855target-specific value indicating the return address of the current function
4856or one of its callers.
4857</p>
4858
4859<h5>Arguments:</h5>
4860
4861<p>
4862The argument to this intrinsic indicates which function to return the address
4863for. Zero indicates the calling function, one indicates its caller, etc. The
4864argument is <b>required</b> to be a constant integer value.
4865</p>
4866
4867<h5>Semantics:</h5>
4868
4869<p>
4870The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4871the return address of the specified call frame, or zero if it cannot be
4872identified. The value returned by this intrinsic is likely to be incorrect or 0
4873for arguments other than zero, so it should only be used for debugging purposes.
4874</p>
4875
4876<p>
4877Note that calling this intrinsic does not prevent function inlining or other
4878aggressive transformations, so the value returned may not be that of the obvious
4879source-language caller.
4880</p>
4881</div>
4882
4883
4884<!-- _______________________________________________________________________ -->
4885<div class="doc_subsubsection">
4886 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
4887</div>
4888
4889<div class="doc_text">
4890
4891<h5>Syntax:</h5>
4892<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4893 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4894</pre>
4895
4896<h5>Overview:</h5>
4897
4898<p>
4899The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4900target-specific frame pointer value for the specified stack frame.
4901</p>
4902
4903<h5>Arguments:</h5>
4904
4905<p>
4906The argument to this intrinsic indicates which function to return the frame
4907pointer for. Zero indicates the calling function, one indicates its caller,
4908etc. The argument is <b>required</b> to be a constant integer value.
4909</p>
4910
4911<h5>Semantics:</h5>
4912
4913<p>
4914The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4915the frame address of the specified call frame, or zero if it cannot be
4916identified. The value returned by this intrinsic is likely to be incorrect or 0
4917for arguments other than zero, so it should only be used for debugging purposes.
4918</p>
4919
4920<p>
4921Note that calling this intrinsic does not prevent function inlining or other
4922aggressive transformations, so the value returned may not be that of the obvious
4923source-language caller.
4924</p>
4925</div>
4926
4927<!-- _______________________________________________________________________ -->
4928<div class="doc_subsubsection">
4929 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
4930</div>
4931
4932<div class="doc_text">
4933
4934<h5>Syntax:</h5>
4935<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4936 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4937</pre>
4938
4939<h5>Overview:</h5>
4940
4941<p>
4942The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
4943the function stack, for use with <a href="#int_stackrestore">
4944<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4945features like scoped automatic variable sized arrays in C99.
4946</p>
4947
4948<h5>Semantics:</h5>
4949
4950<p>
4951This intrinsic returns a opaque pointer value that can be passed to <a
4952href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
4953<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4954<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4955state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4956practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4957that were allocated after the <tt>llvm.stacksave</tt> was executed.
4958</p>
4959
4960</div>
4961
4962<!-- _______________________________________________________________________ -->
4963<div class="doc_subsubsection">
4964 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
4965</div>
4966
4967<div class="doc_text">
4968
4969<h5>Syntax:</h5>
4970<pre>
4971 declare void @llvm.stackrestore(i8 * %ptr)
4972</pre>
4973
4974<h5>Overview:</h5>
4975
4976<p>
4977The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4978the function stack to the state it was in when the corresponding <a
4979href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
4980useful for implementing language features like scoped automatic variable sized
4981arrays in C99.
4982</p>
4983
4984<h5>Semantics:</h5>
4985
4986<p>
4987See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
4988</p>
4989
4990</div>
4991
4992
4993<!-- _______________________________________________________________________ -->
4994<div class="doc_subsubsection">
4995 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
4996</div>
4997
4998<div class="doc_text">
4999
5000<h5>Syntax:</h5>
5001<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5002 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]5003</pre>
5004
5005<h5>Overview:</h5>
5006
5007
5008<p>
5009The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
5010a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
5011no
5012effect on the behavior of the program but can change its performance
5013characteristics.
5014</p>
5015
5016<h5>Arguments:</h5>
5017
5018<p>
5019<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
5020determining if the fetch should be for a read (0) or write (1), and
5021<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5022locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
5023<tt>locality</tt> arguments must be constant integers.
5024</p>
5025
5026<h5>Semantics:</h5>
5027
5028<p>
5029This intrinsic does not modify the behavior of the program. In particular,
5030prefetches cannot trap and do not produce a value. On targets that support this
5031intrinsic, the prefetch can provide hints to the processor cache for better
5032performance.
5033</p>
5034
5035</div>
5036
5037<!-- _______________________________________________________________________ -->
5038<div class="doc_subsubsection">
5039 <a name="int_pcmarker">'<tt>llvm.pcmarker</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 void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5047</pre>
5048
5049<h5>Overview:</h5>
5050
5051
5052<p>
5053The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5054(PC) in a region of
5055code to simulators and other tools. The method is target specific, but it is
5056expected that the marker will use exported symbols to transmit the PC of the
5057marker.
5058The marker makes no guarantees that it will remain with any specific instruction
5059after optimizations. It is possible that the presence of a marker will inhibit
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5060optimizations. The intended use is to be inserted after optimizations to allow
5061correlations of simulation runs.
5062</p>
5063
5064<h5>Arguments:</h5>
5065
5066<p>
5067<tt>id</tt> is a numerical id identifying the marker.
5068</p>
5069
5070<h5>Semantics:</h5>
5071
5072<p>
5073This intrinsic does not modify the behavior of the program. Backends that do not
5074support this intrinisic may ignore it.
5075</p>
5076
5077</div>
5078
5079<!-- _______________________________________________________________________ -->
5080<div class="doc_subsubsection">
5081 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5082</div>
5083
5084<div class="doc_text">
5085
5086<h5>Syntax:</h5>
5087<pre>
5088 declare i64 @llvm.readcyclecounter( )
5089</pre>
5090
5091<h5>Overview:</h5>
5092
5093
5094<p>
5095The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5096counter register (or similar low latency, high accuracy clocks) on those targets
5097that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
5098As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
5099should only be used for small timings.
5100</p>
5101
5102<h5>Semantics:</h5>
5103
5104<p>
5105When directly supported, reading the cycle counter should not modify any memory.
5106Implementations are allowed to either return a application specific value or a
5107system wide value. On backends without support, this is lowered to a constant 0.
5108</p>
5109
5110</div>
5111
5112<!-- ======================================================================= -->
5113<div class="doc_subsection">
5114 <a name="int_libc">Standard C Library Intrinsics</a>
5115</div>
5116
5117<div class="doc_text">
5118<p>
5119LLVM provides intrinsics for a few important standard C library functions.
5120These intrinsics allow source-language front-ends to pass information about the
5121alignment of the pointer arguments to the code generator, providing opportunity
5122for more efficient code generation.
5123</p>
5124
5125</div>
5126
5127<!-- _______________________________________________________________________ -->
5128<div class="doc_subsubsection">
5129 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5130</div>
5131
5132<div class="doc_text">
5133
5134<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5135<p>This is an overloaded intrinsic. You can use llvm.memcpy on any integer bit
5136width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5137<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5138 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5139 i8 &lt;len&gt;, i32 &lt;align&gt;)
5140 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5141 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5142 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5143 i32 &lt;len&gt;, i32 &lt;align&gt;)
5144 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5145 i64 &lt;len&gt;, i32 &lt;align&gt;)
5146</pre>
5147
5148<h5>Overview:</h5>
5149
5150<p>
5151The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5152location to the destination location.
5153</p>
5154
5155<p>
5156Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5157intrinsics do not return a value, and takes an extra alignment argument.
5158</p>
5159
5160<h5>Arguments:</h5>
5161
5162<p>
5163The first argument is a pointer to the destination, the second is a pointer to
5164the source. The third argument is an integer argument
5165specifying the number of bytes to copy, and the fourth argument is the alignment
5166of the source and destination locations.
5167</p>
5168
5169<p>
5170If the call to this intrinisic has an alignment value that is not 0 or 1, then
5171the caller guarantees that both the source and destination pointers are aligned
5172to that boundary.
5173</p>
5174
5175<h5>Semantics:</h5>
5176
5177<p>
5178The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5179location to the destination location, which are not allowed to overlap. It
5180copies "len" bytes of memory over. If the argument is known to be aligned to
5181some boundary, this can be specified as the fourth argument, otherwise it should
5182be set to 0 or 1.
5183</p>
5184</div>
5185
5186
5187<!-- _______________________________________________________________________ -->
5188<div class="doc_subsubsection">
5189 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5190</div>
5191
5192<div class="doc_text">
5193
5194<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5195<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
5196width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5197<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5198 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5199 i8 &lt;len&gt;, i32 &lt;align&gt;)
5200 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5201 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5202 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5203 i32 &lt;len&gt;, i32 &lt;align&gt;)
5204 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5205 i64 &lt;len&gt;, i32 &lt;align&gt;)
5206</pre>
5207
5208<h5>Overview:</h5>
5209
5210<p>
5211The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5212location to the destination location. It is similar to the
Chris Lattnerdba16ea2008-01-06 19:51:52 +0000[diff] [blame]5213'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5214</p>
5215
5216<p>
5217Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5218intrinsics do not return a value, and takes an extra alignment argument.
5219</p>
5220
5221<h5>Arguments:</h5>
5222
5223<p>
5224The first argument is a pointer to the destination, the second is a pointer to
5225the source. The third argument is an integer argument
5226specifying the number of bytes to copy, and the fourth argument is the alignment
5227of the source and destination locations.
5228</p>
5229
5230<p>
5231If the call to this intrinisic has an alignment value that is not 0 or 1, then
5232the caller guarantees that the source and destination pointers are aligned to
5233that boundary.
5234</p>
5235
5236<h5>Semantics:</h5>
5237
5238<p>
5239The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
5240location to the destination location, which may overlap. It
5241copies "len" bytes of memory over. If the argument is known to be aligned to
5242some boundary, this can be specified as the fourth argument, otherwise it should
5243be set to 0 or 1.
5244</p>
5245</div>
5246
5247
5248<!-- _______________________________________________________________________ -->
5249<div class="doc_subsubsection">
5250 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5251</div>
5252
5253<div class="doc_text">
5254
5255<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5256<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
5257width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5258<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5259 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5260 i8 &lt;len&gt;, i32 &lt;align&gt;)
5261 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5262 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5263 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5264 i32 &lt;len&gt;, i32 &lt;align&gt;)
5265 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5266 i64 &lt;len&gt;, i32 &lt;align&gt;)
5267</pre>
5268
5269<h5>Overview:</h5>
5270
5271<p>
5272The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
5273byte value.
5274</p>
5275
5276<p>
5277Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5278does not return a value, and takes an extra alignment argument.
5279</p>
5280
5281<h5>Arguments:</h5>
5282
5283<p>
5284The first argument is a pointer to the destination to fill, the second is the
5285byte value to fill it with, the third argument is an integer
5286argument specifying the number of bytes to fill, and the fourth argument is the
5287known alignment of destination location.
5288</p>
5289
5290<p>
5291If the call to this intrinisic has an alignment value that is not 0 or 1, then
5292the caller guarantees that the destination pointer is aligned to that boundary.
5293</p>
5294
5295<h5>Semantics:</h5>
5296
5297<p>
5298The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5299the
5300destination location. If the argument is known to be aligned to some boundary,
5301this can be specified as the fourth argument, otherwise it should be set to 0 or
53021.
5303</p>
5304</div>
5305
5306
5307<!-- _______________________________________________________________________ -->
5308<div class="doc_subsubsection">
5309 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5310</div>
5311
5312<div class="doc_text">
5313
5314<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5315<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]5316floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5317types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5318<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5319 declare float @llvm.sqrt.f32(float %Val)
5320 declare double @llvm.sqrt.f64(double %Val)
5321 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5322 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5323 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5324</pre>
5325
5326<h5>Overview:</h5>
5327
5328<p>
5329The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5330returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5331<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattnerf914a002008-01-29 07:00:44 +0000[diff] [blame]5332negative numbers other than -0.0 (which allows for better optimization, because
5333there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5334defined to return -0.0 like IEEE sqrt.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5335</p>
5336
5337<h5>Arguments:</h5>
5338
5339<p>
5340The argument and return value are floating point numbers of the same type.
5341</p>
5342
5343<h5>Semantics:</h5>
5344
5345<p>
5346This function returns the sqrt of the specified operand if it is a nonnegative
5347floating point number.
5348</p>
5349</div>
5350
5351<!-- _______________________________________________________________________ -->
5352<div class="doc_subsubsection">
5353 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5354</div>
5355
5356<div class="doc_text">
5357
5358<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5359<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]5360floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5361types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5362<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5363 declare float @llvm.powi.f32(float %Val, i32 %power)
5364 declare double @llvm.powi.f64(double %Val, i32 %power)
5365 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5366 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5367 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5368</pre>
5369
5370<h5>Overview:</h5>
5371
5372<p>
5373The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5374specified (positive or negative) power. The order of evaluation of
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5375multiplications is not defined. When a vector of floating point type is
5376used, the second argument remains a scalar integer value.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5377</p>
5378
5379<h5>Arguments:</h5>
5380
5381<p>
5382The second argument is an integer power, and the first is a value to raise to
5383that power.
5384</p>
5385
5386<h5>Semantics:</h5>
5387
5388<p>
5389This function returns the first value raised to the second power with an
5390unspecified sequence of rounding operations.</p>
5391</div>
5392
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5393<!-- _______________________________________________________________________ -->
5394<div class="doc_subsubsection">
5395 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5396</div>
5397
5398<div class="doc_text">
5399
5400<h5>Syntax:</h5>
5401<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5402floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5403types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5404<pre>
5405 declare float @llvm.sin.f32(float %Val)
5406 declare double @llvm.sin.f64(double %Val)
5407 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5408 declare fp128 @llvm.sin.f128(fp128 %Val)
5409 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5410</pre>
5411
5412<h5>Overview:</h5>
5413
5414<p>
5415The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5416</p>
5417
5418<h5>Arguments:</h5>
5419
5420<p>
5421The argument and return value are floating point numbers of the same type.
5422</p>
5423
5424<h5>Semantics:</h5>
5425
5426<p>
5427This function returns the sine of the specified operand, returning the
5428same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5429conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5430</div>
5431
5432<!-- _______________________________________________________________________ -->
5433<div class="doc_subsubsection">
5434 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5435</div>
5436
5437<div class="doc_text">
5438
5439<h5>Syntax:</h5>
5440<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5441floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5442types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5443<pre>
5444 declare float @llvm.cos.f32(float %Val)
5445 declare double @llvm.cos.f64(double %Val)
5446 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5447 declare fp128 @llvm.cos.f128(fp128 %Val)
5448 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5449</pre>
5450
5451<h5>Overview:</h5>
5452
5453<p>
5454The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5455</p>
5456
5457<h5>Arguments:</h5>
5458
5459<p>
5460The argument and return value are floating point numbers of the same type.
5461</p>
5462
5463<h5>Semantics:</h5>
5464
5465<p>
5466This function returns the cosine of the specified operand, returning the
5467same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5468conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5469</div>
5470
5471<!-- _______________________________________________________________________ -->
5472<div class="doc_subsubsection">
5473 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5474</div>
5475
5476<div class="doc_text">
5477
5478<h5>Syntax:</h5>
5479<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5480floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5481types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5482<pre>
5483 declare float @llvm.pow.f32(float %Val, float %Power)
5484 declare double @llvm.pow.f64(double %Val, double %Power)
5485 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5486 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5487 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5488</pre>
5489
5490<h5>Overview:</h5>
5491
5492<p>
5493The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5494specified (positive or negative) power.
5495</p>
5496
5497<h5>Arguments:</h5>
5498
5499<p>
5500The second argument is a floating point power, and the first is a value to
5501raise to that power.
5502</p>
5503
5504<h5>Semantics:</h5>
5505
5506<p>
5507This function returns the first value raised to the second power,
5508returning the
5509same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5510conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5511</div>
5512
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5513
5514<!-- ======================================================================= -->
5515<div class="doc_subsection">
5516 <a name="int_manip">Bit Manipulation Intrinsics</a>
5517</div>
5518
5519<div class="doc_text">
5520<p>
5521LLVM provides intrinsics for a few important bit manipulation operations.
5522These allow efficient code generation for some algorithms.
5523</p>
5524
5525</div>
5526
5527<!-- _______________________________________________________________________ -->
5528<div class="doc_subsubsection">
5529 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5530</div>
5531
5532<div class="doc_text">
5533
5534<h5>Syntax:</h5>
5535<p>This is an overloaded intrinsic function. You can use bswap on any integer
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5536type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5537<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5538 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5539 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5540 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5541</pre>
5542
5543<h5>Overview:</h5>
5544
5545<p>
5546The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5547values with an even number of bytes (positive multiple of 16 bits). These are
5548useful for performing operations on data that is not in the target's native
5549byte order.
5550</p>
5551
5552<h5>Semantics:</h5>
5553
5554<p>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5555The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5556and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5557intrinsic returns an i32 value that has the four bytes of the input i32
5558swapped, 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]5559i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5560<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5561additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
5562</p>
5563
5564</div>
5565
5566<!-- _______________________________________________________________________ -->
5567<div class="doc_subsubsection">
5568 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5569</div>
5570
5571<div class="doc_text">
5572
5573<h5>Syntax:</h5>
5574<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]5575width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5576<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5577 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
5578 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5579 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5580 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5581 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5582</pre>
5583
5584<h5>Overview:</h5>
5585
5586<p>
5587The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5588value.
5589</p>
5590
5591<h5>Arguments:</h5>
5592
5593<p>
5594The only argument is the value to be counted. The argument may be of any
5595integer type. The return type must match the argument type.
5596</p>
5597
5598<h5>Semantics:</h5>
5599
5600<p>
5601The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5602</p>
5603</div>
5604
5605<!-- _______________________________________________________________________ -->
5606<div class="doc_subsubsection">
5607 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5608</div>
5609
5610<div class="doc_text">
5611
5612<h5>Syntax:</h5>
5613<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]5614integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5615<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5616 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5617 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5618 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5619 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5620 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5621</pre>
5622
5623<h5>Overview:</h5>
5624
5625<p>
5626The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5627leading zeros in a variable.
5628</p>
5629
5630<h5>Arguments:</h5>
5631
5632<p>
5633The only argument is the value to be counted. The argument may be of any
5634integer type. The return type must match the argument type.
5635</p>
5636
5637<h5>Semantics:</h5>
5638
5639<p>
5640The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5641in a variable. If the src == 0 then the result is the size in bits of the type
5642of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
5643</p>
5644</div>
5645
5646
5647
5648<!-- _______________________________________________________________________ -->
5649<div class="doc_subsubsection">
5650 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5651</div>
5652
5653<div class="doc_text">
5654
5655<h5>Syntax:</h5>
5656<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]5657integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5658<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5659 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5660 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5661 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5662 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5663 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5664</pre>
5665
5666<h5>Overview:</h5>
5667
5668<p>
5669The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5670trailing zeros.
5671</p>
5672
5673<h5>Arguments:</h5>
5674
5675<p>
5676The only argument is the value to be counted. The argument may be of any
5677integer type. The return type must match the argument type.
5678</p>
5679
5680<h5>Semantics:</h5>
5681
5682<p>
5683The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5684in a variable. If the src == 0 then the result is the size in bits of the type
5685of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5686</p>
5687</div>
5688
5689<!-- _______________________________________________________________________ -->
5690<div class="doc_subsubsection">
5691 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
5692</div>
5693
5694<div class="doc_text">
5695
5696<h5>Syntax:</h5>
5697<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5698on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5699<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5700 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5701 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5702</pre>
5703
5704<h5>Overview:</h5>
5705<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
5706range of bits from an integer value and returns them in the same bit width as
5707the original value.</p>
5708
5709<h5>Arguments:</h5>
5710<p>The first argument, <tt>%val</tt> and the result may be integer types of
5711any bit width but they must have the same bit width. The second and third
5712arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
5713
5714<h5>Semantics:</h5>
5715<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
5716of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5717<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5718operates in forward mode.</p>
5719<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5720right by <tt>%loBit</tt> bits and then ANDing it with a mask with
5721only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5722<ol>
5723 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5724 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5725 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5726 to determine the number of bits to retain.</li>
5727 <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]5728 <li>The mask is ANDed with <tt>%val</tt> to produce the result.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5729</ol>
5730<p>In reverse mode, a similar computation is made except that the bits are
5731returned in the reverse order. So, for example, if <tt>X</tt> has the value
5732<tt>i16 0x0ACF (101011001111)</tt> and we apply
5733<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5734<tt>i16 0x0026 (000000100110)</tt>.</p>
5735</div>
5736
5737<div class="doc_subsubsection">
5738 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5739</div>
5740
5741<div class="doc_text">
5742
5743<h5>Syntax:</h5>
5744<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5745on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5746<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5747 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5748 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]5749</pre>
5750
5751<h5>Overview:</h5>
5752<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5753of bits in an integer value with another integer value. It returns the integer
5754with the replaced bits.</p>
5755
5756<h5>Arguments:</h5>
5757<p>The first argument, <tt>%val</tt> and the result may be integer types of
5758any bit width but they must have the same bit width. <tt>%val</tt> is the value
5759whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5760integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5761type since they specify only a bit index.</p>
5762
5763<h5>Semantics:</h5>
5764<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5765of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5766<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5767operates in forward mode.</p>
5768<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5769truncating it down to the size of the replacement area or zero extending it
5770up to that size.</p>
5771<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5772are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5773in <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]5774to the <tt>%hi</tt>th bit.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5775<p>In reverse mode, a similar computation is made except that the bits are
5776reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5777<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]5778<h5>Examples:</h5>
5779<pre>
5780 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
5781 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5782 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5783 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
5784 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
5785</pre>
5786</div>
5787
5788<!-- ======================================================================= -->
5789<div class="doc_subsection">
5790 <a name="int_debugger">Debugger Intrinsics</a>
5791</div>
5792
5793<div class="doc_text">
5794<p>
5795The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5796are described in the <a
5797href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5798Debugging</a> document.
5799</p>
5800</div>
5801
5802
5803<!-- ======================================================================= -->
5804<div class="doc_subsection">
5805 <a name="int_eh">Exception Handling Intrinsics</a>
5806</div>
5807
5808<div class="doc_text">
5809<p> The LLVM exception handling intrinsics (which all start with
5810<tt>llvm.eh.</tt> prefix), are described in the <a
5811href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5812Handling</a> document. </p>
5813</div>
5814
5815<!-- ======================================================================= -->
5816<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5817 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5818</div>
5819
5820<div class="doc_text">
5821<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5822 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5823 the <tt>nest</tt> attribute, from a function. The result is a callable
5824 function pointer lacking the nest parameter - the caller does not need
5825 to provide a value for it. Instead, the value to use is stored in
5826 advance in a "trampoline", a block of memory usually allocated
5827 on the stack, which also contains code to splice the nest value into the
5828 argument list. This is used to implement the GCC nested function address
5829 extension.
5830</p>
5831<p>
5832 For example, if the function is
5833 <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]5834 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]5835<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5836 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5837 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5838 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5839 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5840</pre>
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]5841 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5842 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5843</div>
5844
5845<!-- _______________________________________________________________________ -->
5846<div class="doc_subsubsection">
5847 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5848</div>
5849<div class="doc_text">
5850<h5>Syntax:</h5>
5851<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5852declare 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]5853</pre>
5854<h5>Overview:</h5>
5855<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5856 This fills the memory pointed to by <tt>tramp</tt> with code
5857 and returns a function pointer suitable for executing it.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5858</p>
5859<h5>Arguments:</h5>
5860<p>
5861 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5862 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5863 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sands35012212007-08-22 23:39:54 +0000[diff] [blame]5864 intrinsic. Note that the size and the alignment are target-specific - LLVM
5865 currently provides no portable way of determining them, so a front-end that
5866 generates this intrinsic needs to have some target-specific knowledge.
5867 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]5868</p>
5869<h5>Semantics:</h5>
5870<p>
5871 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5872 dependent code, turning it into a function. A pointer to this function is
5873 returned, but needs to be bitcast to an
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5874 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5875 before being called. The new function's signature is the same as that of
5876 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5877 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5878 of pointer type. Calling the new function is equivalent to calling
5879 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5880 missing <tt>nest</tt> argument. If, after calling
5881 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5882 modified, then the effect of any later call to the returned function pointer is
5883 undefined.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5884</p>
5885</div>
5886
5887<!-- ======================================================================= -->
5888<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5889 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
5890</div>
5891
5892<div class="doc_text">
5893<p>
5894 These intrinsic functions expand the "universal IR" of LLVM to represent
5895 hardware constructs for atomic operations and memory synchronization. This
5896 provides an interface to the hardware, not an interface to the programmer. It
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5897 is aimed at a low enough level to allow any programming models or APIs
5898 (Application Programming Interfaces) which
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5899 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
5900 hardware behavior. Just as hardware provides a "universal IR" for source
5901 languages, it also provides a starting point for developing a "universal"
5902 atomic operation and synchronization IR.
5903</p>
5904<p>
5905 These do <em>not</em> form an API such as high-level threading libraries,
5906 software transaction memory systems, atomic primitives, and intrinsic
5907 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
5908 application libraries. The hardware interface provided by LLVM should allow
5909 a clean implementation of all of these APIs and parallel programming models.
5910 No one model or paradigm should be selected above others unless the hardware
5911 itself ubiquitously does so.
5912
5913</p>
5914</div>
5915
5916<!-- _______________________________________________________________________ -->
5917<div class="doc_subsubsection">
5918 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5919</div>
5920<div class="doc_text">
5921<h5>Syntax:</h5>
5922<pre>
5923declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
5924i1 &lt;device&gt; )
5925
5926</pre>
5927<h5>Overview:</h5>
5928<p>
5929 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5930 specific pairs of memory access types.
5931</p>
5932<h5>Arguments:</h5>
5933<p>
5934 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
5935 The first four arguments enables a specific barrier as listed below. The fith
5936 argument specifies that the barrier applies to io or device or uncached memory.
5937
5938</p>
5939 <ul>
5940 <li><tt>ll</tt>: load-load barrier</li>
5941 <li><tt>ls</tt>: load-store barrier</li>
5942 <li><tt>sl</tt>: store-load barrier</li>
5943 <li><tt>ss</tt>: store-store barrier</li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5944 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5945 </ul>
5946<h5>Semantics:</h5>
5947<p>
5948 This intrinsic causes the system to enforce some ordering constraints upon
5949 the loads and stores of the program. This barrier does not indicate
5950 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5951 which they occur. For any of the specified pairs of load and store operations
5952 (f.ex. load-load, or store-load), all of the first operations preceding the
5953 barrier will complete before any of the second operations succeeding the
5954 barrier begin. Specifically the semantics for each pairing is as follows:
5955</p>
5956 <ul>
5957 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5958 after the barrier begins.</li>
5959
5960 <li><tt>ls</tt>: All loads before the barrier must complete before any
5961 store after the barrier begins.</li>
5962 <li><tt>ss</tt>: All stores before the barrier must complete before any
5963 store after the barrier begins.</li>
5964 <li><tt>sl</tt>: All stores before the barrier must complete before any
5965 load after the barrier begins.</li>
5966 </ul>
5967<p>
5968 These semantics are applied with a logical "and" behavior when more than one
5969 is enabled in a single memory barrier intrinsic.
5970</p>
5971<p>
5972 Backends may implement stronger barriers than those requested when they do not
5973 support as fine grained a barrier as requested. Some architectures do not
5974 need all types of barriers and on such architectures, these become noops.
5975</p>
5976<h5>Example:</h5>
5977<pre>
5978%ptr = malloc i32
5979 store i32 4, %ptr
5980
5981%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
5982 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
5983 <i>; guarantee the above finishes</i>
5984 store i32 8, %ptr <i>; before this begins</i>
5985</pre>
5986</div>
5987
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5988<!-- _______________________________________________________________________ -->
5989<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5990 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5991</div>
5992<div class="doc_text">
5993<h5>Syntax:</h5>
5994<p>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5995 This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
5996 any integer bit width and for different address spaces. Not all targets
5997 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5998
5999<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6000declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6001declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6002declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6003declare 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]6004
6005</pre>
6006<h5>Overview:</h5>
6007<p>
6008 This loads a value in memory and compares it to a given value. If they are
6009 equal, it stores a new value into the memory.
6010</p>
6011<h5>Arguments:</h5>
6012<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6013 The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6014 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6015 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6016 this integer type. While any bit width integer may be used, targets may only
6017 lower representations they support in hardware.
6018
6019</p>
6020<h5>Semantics:</h5>
6021<p>
6022 This entire intrinsic must be executed atomically. It first loads the value
6023 in memory pointed to by <tt>ptr</tt> and compares it with the value
6024 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
6025 loaded value is yielded in all cases. This provides the equivalent of an
6026 atomic compare-and-swap operation within the SSA framework.
6027</p>
6028<h5>Examples:</h5>
6029
6030<pre>
6031%ptr = malloc i32
6032 store i32 4, %ptr
6033
6034%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6035%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6036 <i>; yields {i32}:result1 = 4</i>
6037%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6038%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6039
6040%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6041%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6042 <i>; yields {i32}:result2 = 8</i>
6043%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6044
6045%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6046</pre>
6047</div>
6048
6049<!-- _______________________________________________________________________ -->
6050<div class="doc_subsubsection">
6051 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6052</div>
6053<div class="doc_text">
6054<h5>Syntax:</h5>
6055
6056<p>
6057 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6058 integer bit width. Not all targets support all bit widths however.</p>
6059<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6060declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6061declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6062declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6063declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6064
6065</pre>
6066<h5>Overview:</h5>
6067<p>
6068 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6069 the value from memory. It then stores the value in <tt>val</tt> in the memory
6070 at <tt>ptr</tt>.
6071</p>
6072<h5>Arguments:</h5>
6073
6074<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6075 The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6076 <tt>val</tt> argument and the result must be integers of the same bit width.
6077 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6078 integer type. The targets may only lower integer representations they
6079 support.
6080</p>
6081<h5>Semantics:</h5>
6082<p>
6083 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6084 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6085 equivalent of an atomic swap operation within the SSA framework.
6086
6087</p>
6088<h5>Examples:</h5>
6089<pre>
6090%ptr = malloc i32
6091 store i32 4, %ptr
6092
6093%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6094%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6095 <i>; yields {i32}:result1 = 4</i>
6096%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6097%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6098
6099%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6100%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6101 <i>; yields {i32}:result2 = 8</i>
6102
6103%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6104%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6105</pre>
6106</div>
6107
6108<!-- _______________________________________________________________________ -->
6109<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6110 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6111
6112</div>
6113<div class="doc_text">
6114<h5>Syntax:</h5>
6115<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6116 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]6117 integer bit width. Not all targets support all bit widths however.</p>
6118<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6119declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6120declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6121declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6122declare 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]6123
6124</pre>
6125<h5>Overview:</h5>
6126<p>
6127 This intrinsic adds <tt>delta</tt> to the value stored in memory at
6128 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6129</p>
6130<h5>Arguments:</h5>
6131<p>
6132
6133 The intrinsic takes two arguments, the first a pointer to an integer value
6134 and the second an integer value. The result is also an integer value. These
6135 integer types can have any bit width, but they must all have the same bit
6136 width. The targets may only lower integer representations they support.
6137</p>
6138<h5>Semantics:</h5>
6139<p>
6140 This intrinsic does a series of operations atomically. It first loads the
6141 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6142 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6143</p>
6144
6145<h5>Examples:</h5>
6146<pre>
6147%ptr = malloc i32
6148 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6149%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6150 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6151%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6152 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6153%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6154 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6155%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6156</pre>
6157</div>
6158
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6159<!-- _______________________________________________________________________ -->
6160<div class="doc_subsubsection">
6161 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6162
6163</div>
6164<div class="doc_text">
6165<h5>Syntax:</h5>
6166<p>
6167 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]6168 any integer bit width and for different address spaces. Not all targets
6169 support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6170<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6171declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6172declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6173declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6174declare 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]6175
6176</pre>
6177<h5>Overview:</h5>
6178<p>
6179 This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6180 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6181</p>
6182<h5>Arguments:</h5>
6183<p>
6184
6185 The intrinsic takes two arguments, the first a pointer to an integer value
6186 and the second an integer value. The result is also an integer value. These
6187 integer types can have any bit width, but they must all have the same bit
6188 width. The targets may only lower integer representations they support.
6189</p>
6190<h5>Semantics:</h5>
6191<p>
6192 This intrinsic does a series of operations atomically. It first loads the
6193 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6194 result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6195</p>
6196
6197<h5>Examples:</h5>
6198<pre>
6199%ptr = malloc i32
6200 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6201%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6202 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6203%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6204 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6205%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6206 <i>; yields {i32}:result3 = 2</i>
6207%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6208</pre>
6209</div>
6210
6211<!-- _______________________________________________________________________ -->
6212<div class="doc_subsubsection">
6213 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6214 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6215 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6216 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
6217
6218</div>
6219<div class="doc_text">
6220<h5>Syntax:</h5>
6221<p>
6222 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
6223 <tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6224 <tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
6225 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6226<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6227declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6228declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6229declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6230declare 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]6231
6232</pre>
6233
6234<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6235declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6236declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6237declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6238declare 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]6239
6240</pre>
6241
6242<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6243declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6244declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6245declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6246declare 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]6247
6248</pre>
6249
6250<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6251declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6252declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6253declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6254declare 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]6255
6256</pre>
6257<h5>Overview:</h5>
6258<p>
6259 These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6260 the value stored in memory at <tt>ptr</tt>. It yields the original value
6261 at <tt>ptr</tt>.
6262</p>
6263<h5>Arguments:</h5>
6264<p>
6265
6266 These intrinsics take two arguments, the first a pointer to an integer value
6267 and the second an integer value. The result is also an integer value. These
6268 integer types can have any bit width, but they must all have the same bit
6269 width. The targets may only lower integer representations they support.
6270</p>
6271<h5>Semantics:</h5>
6272<p>
6273 These intrinsics does a series of operations atomically. They first load the
6274 value stored at <tt>ptr</tt>. They then do the bitwise operation
6275 <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
6276 value stored at <tt>ptr</tt>.
6277</p>
6278
6279<h5>Examples:</h5>
6280<pre>
6281%ptr = malloc i32
6282 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6283%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6284 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6285%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6286 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6287%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6288 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6289%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6290 <i>; yields {i32}:result3 = FF</i>
6291%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6292</pre>
6293</div>
6294
6295
6296<!-- _______________________________________________________________________ -->
6297<div class="doc_subsubsection">
6298 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6299 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6300 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6301 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
6302
6303</div>
6304<div class="doc_text">
6305<h5>Syntax:</h5>
6306<p>
6307 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6308 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6309 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6310 address spaces. Not all targets
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6311 support all bit widths however.</p>
6312<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6313declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6314declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6315declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6316declare 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]6317
6318</pre>
6319
6320<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6321declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6322declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6323declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6324declare 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]6325
6326</pre>
6327
6328<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6329declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6330declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6331declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6332declare 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]6333
6334</pre>
6335
6336<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6337declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6338declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6339declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6340declare 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]6341
6342</pre>
6343<h5>Overview:</h5>
6344<p>
6345 These intrinsics takes the signed or unsigned minimum or maximum of
6346 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6347 original value at <tt>ptr</tt>.
6348</p>
6349<h5>Arguments:</h5>
6350<p>
6351
6352 These intrinsics take two arguments, the first a pointer to an integer value
6353 and the second an integer value. The result is also an integer value. These
6354 integer types can have any bit width, but they must all have the same bit
6355 width. The targets may only lower integer representations they support.
6356</p>
6357<h5>Semantics:</h5>
6358<p>
6359 These intrinsics does a series of operations atomically. They first load the
6360 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
6361 <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
6362 the original value stored at <tt>ptr</tt>.
6363</p>
6364
6365<h5>Examples:</h5>
6366<pre>
6367%ptr = malloc i32
6368 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6369%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6370 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6371%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6372 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6373%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6374 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6375%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6376 <i>; yields {i32}:result3 = 8</i>
6377%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6378</pre>
6379</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6380
6381<!-- ======================================================================= -->
6382<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6383 <a name="int_general">General Intrinsics</a>
6384</div>
6385
6386<div class="doc_text">
6387<p> This class of intrinsics is designed to be generic and has
6388no specific purpose. </p>
6389</div>
6390
6391<!-- _______________________________________________________________________ -->
6392<div class="doc_subsubsection">
6393 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6394</div>
6395
6396<div class="doc_text">
6397
6398<h5>Syntax:</h5>
6399<pre>
6400 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6401</pre>
6402
6403<h5>Overview:</h5>
6404
6405<p>
6406The '<tt>llvm.var.annotation</tt>' intrinsic
6407</p>
6408
6409<h5>Arguments:</h5>
6410
6411<p>
6412The first argument is a pointer to a value, the second is a pointer to a
6413global string, the third is a pointer to a global string which is the source
6414file name, and the last argument is the line number.
6415</p>
6416
6417<h5>Semantics:</h5>
6418
6419<p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6420This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6421This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6422annotations. These have no other defined use, they are ignored by code
6423generation and optimization.
6424</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6425</div>
6426
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6427<!-- _______________________________________________________________________ -->
6428<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]6429 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6430</div>
6431
6432<div class="doc_text">
6433
6434<h5>Syntax:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6435<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6436any integer bit width.
6437</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6438<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]6439 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6440 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6441 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6442 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6443 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]6444</pre>
6445
6446<h5>Overview:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6447
6448<p>
6449The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6450</p>
6451
6452<h5>Arguments:</h5>
6453
6454<p>
6455The first argument is an integer value (result of some expression),
6456the second is a pointer to a global string, the third is a pointer to a global
6457string which is the source file name, and the last argument is the line number.
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6458It returns the value of the first argument.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6459</p>
6460
6461<h5>Semantics:</h5>
6462
6463<p>
6464This intrinsic allows annotations to be put on arbitrary expressions
6465with arbitrary strings. This can be useful for special purpose optimizations
6466that want to look for these annotations. These have no other defined use, they
6467are ignored by code generation and optimization.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6468</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6469</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6470
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6471<!-- _______________________________________________________________________ -->
6472<div class="doc_subsubsection">
6473 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6474</div>
6475
6476<div class="doc_text">
6477
6478<h5>Syntax:</h5>
6479<pre>
6480 declare void @llvm.trap()
6481</pre>
6482
6483<h5>Overview:</h5>
6484
6485<p>
6486The '<tt>llvm.trap</tt>' intrinsic
6487</p>
6488
6489<h5>Arguments:</h5>
6490
6491<p>
6492None
6493</p>
6494
6495<h5>Semantics:</h5>
6496
6497<p>
6498This intrinsics is lowered to the target dependent trap instruction. If the
6499target does not have a trap instruction, this intrinsic will be lowered to the
6500call of the abort() function.
6501</p>
6502</div>
6503
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6504<!-- _______________________________________________________________________ -->
6505<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]6506 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6507</div>
6508<div class="doc_text">
6509<h5>Syntax:</h5>
6510<pre>
6511declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
6512
6513</pre>
6514<h5>Overview:</h5>
6515<p>
6516 The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and stores
6517 it onto the stack at <tt>slot</tt>. The stack slot is adjusted to ensure that
6518 it is placed on the stack before local variables.
6519</p>
6520<h5>Arguments:</h5>
6521<p>
6522 The <tt>llvm.stackprotector</tt> intrinsic requires two pointer arguments. The
6523 first argument is the value loaded from the stack guard
6524 <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt> that
6525 has enough space to hold the value of the guard.
6526</p>
6527<h5>Semantics:</h5>
6528<p>
6529 This intrinsic causes the prologue/epilogue inserter to force the position of
6530 the <tt>AllocaInst</tt> stack slot to be before local variables on the
6531 stack. This is to ensure that if a local variable on the stack is overwritten,
6532 it will destroy the value of the guard. When the function exits, the guard on
6533 the stack is checked against the original guard. If they're different, then
6534 the program aborts by calling the <tt>__stack_chk_fail()</tt> function.
6535</p>
6536</div>
6537
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6538<!-- *********************************************************************** -->
6539<hr>
6540<address>
6541 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]6542 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6543 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]6544 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]6545
6546 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
6547 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
6548 Last modified: $Date$
6549</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]6550
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6551</body>
6552</html>