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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / a53eb38654e33a6ee303c24b7bbb65111f074a49 / . / docs / LangRef.html
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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
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]483 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
484
485 <dd>Global values with private linkage are only directly accessible by
486 objects in the current module. In particular, linking code into a module with
487 an private global value may cause the private to be renamed as necessary to
488 avoid collisions. Because the symbol is private to the module, all
489 references can be updated. This doesn't show up in any symbol table in the
490 object file.
491 </dd>
492
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]493 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]494
Duncan Sandsa75223a2009-01-16 09:29:46 +0000[diff] [blame]495 <dd> Similar to private, but the value shows as a local symbol (STB_LOCAL in
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]496 the case of ELF) in the object file. This corresponds to the notion of the
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]497 '<tt>static</tt>' keyword in C.
498 </dd>
499
500 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
501
502 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
503 the same name when linkage occurs. This is typically used to implement
504 inline functions, templates, or other code which must be generated in each
505 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
506 allowed to be discarded.
507 </dd>
508
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]509 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
510
511 <dd>"<tt>common</tt>" linkage is exactly the same as <tt>linkonce</tt>
512 linkage, except that unreferenced <tt>common</tt> globals may not be
513 discarded. This is used for globals that may be emitted in multiple
514 translation units, but that are not guaranteed to be emitted into every
515 translation unit that uses them. One example of this is tentative
516 definitions in C, such as "<tt>int X;</tt>" at global scope.
517 </dd>
518
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]519 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
520
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]521 <dd>"<tt>weak</tt>" linkage is the same as <tt>common</tt> linkage, except
522 that some targets may choose to emit different assembly sequences for them
523 for target-dependent reasons. This is used for globals that are declared
524 "weak" in C source code.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]525 </dd>
526
527 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
528
529 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
530 pointer to array type. When two global variables with appending linkage are
531 linked together, the two global arrays are appended together. This is the
532 LLVM, typesafe, equivalent of having the system linker append together
533 "sections" with identical names when .o files are linked.
534 </dd>
535
536 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]537 <dd>The semantics of this linkage follow the ELF object file model: the
538 symbol is weak until linked, if not linked, the symbol becomes null instead
539 of being an undefined reference.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]540 </dd>
541
542 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
543
544 <dd>If none of the above identifiers are used, the global is externally
545 visible, meaning that it participates in linkage and can be used to resolve
546 external symbol references.
547 </dd>
548</dl>
549
550 <p>
551 The next two types of linkage are targeted for Microsoft Windows platform
552 only. They are designed to support importing (exporting) symbols from (to)
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]553 DLLs (Dynamic Link Libraries).
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]554 </p>
555
556 <dl>
557 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
558
559 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
560 or variable via a global pointer to a pointer that is set up by the DLL
561 exporting the symbol. On Microsoft Windows targets, the pointer name is
Dan Gohman5ec99832009-01-12 21:35:55 +0000[diff] [blame]562 formed by combining <code>__imp_</code> and the function or variable name.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]563 </dd>
564
565 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
566
567 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
568 pointer to a pointer in a DLL, so that it can be referenced with the
569 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
Dan Gohman5ec99832009-01-12 21:35:55 +0000[diff] [blame]570 name is formed by combining <code>__imp_</code> and the function or variable
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]571 name.
572 </dd>
573
574</dl>
575
Dan Gohman4dfac702008-11-24 17:18:39 +0000[diff] [blame]576<p>For example, since the "<tt>.LC0</tt>"
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]577variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
578variable and was linked with this one, one of the two would be renamed,
579preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
580external (i.e., lacking any linkage declarations), they are accessible
581outside of the current module.</p>
582<p>It is illegal for a function <i>declaration</i>
583to have any linkage type other than "externally visible", <tt>dllimport</tt>,
584or <tt>extern_weak</tt>.</p>
585<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]586linkages.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]587</div>
588
589<!-- ======================================================================= -->
590<div class="doc_subsection">
591 <a name="callingconv">Calling Conventions</a>
592</div>
593
594<div class="doc_text">
595
596<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
597and <a href="#i_invoke">invokes</a> can all have an optional calling convention
598specified for the call. The calling convention of any pair of dynamic
599caller/callee must match, or the behavior of the program is undefined. The
600following calling conventions are supported by LLVM, and more may be added in
601the future:</p>
602
603<dl>
604 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
605
606 <dd>This calling convention (the default if no other calling convention is
607 specified) matches the target C calling conventions. This calling convention
608 supports varargs function calls and tolerates some mismatch in the declared
609 prototype and implemented declaration of the function (as does normal C).
610 </dd>
611
612 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
613
614 <dd>This calling convention attempts to make calls as fast as possible
615 (e.g. by passing things in registers). This calling convention allows the
616 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]617 without having to conform to an externally specified ABI (Application Binary
618 Interface). Implementations of this convention should allow arbitrary
Arnold Schwaighofer07444922008-05-14 09:17:12 +0000[diff] [blame]619 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> to be
620 supported. This calling convention does not support varargs and requires the
621 prototype of all callees to exactly match the prototype of the function
622 definition.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]623 </dd>
624
625 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
626
627 <dd>This calling convention attempts to make code in the caller as efficient
628 as possible under the assumption that the call is not commonly executed. As
629 such, these calls often preserve all registers so that the call does not break
630 any live ranges in the caller side. This calling convention does not support
631 varargs and requires the prototype of all callees to exactly match the
632 prototype of the function definition.
633 </dd>
634
635 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
636
637 <dd>Any calling convention may be specified by number, allowing
638 target-specific calling conventions to be used. Target specific calling
639 conventions start at 64.
640 </dd>
641</dl>
642
643<p>More calling conventions can be added/defined on an as-needed basis, to
644support pascal conventions or any other well-known target-independent
645convention.</p>
646
647</div>
648
649<!-- ======================================================================= -->
650<div class="doc_subsection">
651 <a name="visibility">Visibility Styles</a>
652</div>
653
654<div class="doc_text">
655
656<p>
657All Global Variables and Functions have one of the following visibility styles:
658</p>
659
660<dl>
661 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
662
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]663 <dd>On targets that use the ELF object file format, default visibility means
664 that the declaration is visible to other
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]665 modules and, in shared libraries, means that the declared entity may be
666 overridden. On Darwin, default visibility means that the declaration is
667 visible to other modules. Default visibility corresponds to "external
668 linkage" in the language.
669 </dd>
670
671 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
672
673 <dd>Two declarations of an object with hidden visibility refer to the same
674 object if they are in the same shared object. Usually, hidden visibility
675 indicates that the symbol will not be placed into the dynamic symbol table,
676 so no other module (executable or shared library) can reference it
677 directly.
678 </dd>
679
680 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
681
682 <dd>On ELF, protected visibility indicates that the symbol will be placed in
683 the dynamic symbol table, but that references within the defining module will
684 bind to the local symbol. That is, the symbol cannot be overridden by another
685 module.
686 </dd>
687</dl>
688
689</div>
690
691<!-- ======================================================================= -->
692<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]693 <a name="namedtypes">Named Types</a>
694</div>
695
696<div class="doc_text">
697
698<p>LLVM IR allows you to specify name aliases for certain types. This can make
699it easier to read the IR and make the IR more condensed (particularly when
700recursive types are involved). An example of a name specification is:
701</p>
702
703<div class="doc_code">
704<pre>
705%mytype = type { %mytype*, i32 }
706</pre>
707</div>
708
709<p>You may give a name to any <a href="#typesystem">type</a> except "<a
710href="t_void">void</a>". Type name aliases may be used anywhere a type is
711expected with the syntax "%mytype".</p>
712
713<p>Note that type names are aliases for the structural type that they indicate,
714and that you can therefore specify multiple names for the same type. This often
715leads to confusing behavior when dumping out a .ll file. Since LLVM IR uses
716structural typing, the name is not part of the type. When printing out LLVM IR,
717the printer will pick <em>one name</em> to render all types of a particular
718shape. This means that if you have code where two different source types end up
719having the same LLVM type, that the dumper will sometimes print the "wrong" or
720unexpected type. This is an important design point and isn't going to
721change.</p>
722
723</div>
724
725
726<!-- ======================================================================= -->
727<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]728 <a name="globalvars">Global Variables</a>
729</div>
730
731<div class="doc_text">
732
733<p>Global variables define regions of memory allocated at compilation time
734instead of run-time. Global variables may optionally be initialized, may have
735an explicit section to be placed in, and may have an optional explicit alignment
736specified. A variable may be defined as "thread_local", which means that it
737will not be shared by threads (each thread will have a separated copy of the
738variable). A variable may be defined as a global "constant," which indicates
739that the contents of the variable will <b>never</b> be modified (enabling better
740optimization, allowing the global data to be placed in the read-only section of
741an executable, etc). Note that variables that need runtime initialization
742cannot be marked "constant" as there is a store to the variable.</p>
743
744<p>
745LLVM explicitly allows <em>declarations</em> of global variables to be marked
746constant, even if the final definition of the global is not. This capability
747can be used to enable slightly better optimization of the program, but requires
748the language definition to guarantee that optimizations based on the
749'constantness' are valid for the translation units that do not include the
750definition.
751</p>
752
753<p>As SSA values, global variables define pointer values that are in
754scope (i.e. they dominate) all basic blocks in the program. Global
755variables always define a pointer to their "content" type because they
756describe a region of memory, and all memory objects in LLVM are
757accessed through pointers.</p>
758
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]759<p>A global variable may be declared to reside in a target-specifc numbered
760address space. For targets that support them, address spaces may affect how
761optimizations are performed and/or what target instructions are used to access
Christopher Lamb20a39e92007-12-12 08:44:39 +0000[diff] [blame]762the variable. The default address space is zero. The address space qualifier
763must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]764
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]765<p>LLVM allows an explicit section to be specified for globals. If the target
766supports it, it will emit globals to the section specified.</p>
767
768<p>An explicit alignment may be specified for a global. If not present, or if
769the alignment is set to zero, the alignment of the global is set by the target
770to whatever it feels convenient. If an explicit alignment is specified, the
771global is forced to have at least that much alignment. All alignments must be
772a power of 2.</p>
773
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]774<p>For example, the following defines a global in a numbered address space with
775an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]776
777<div class="doc_code">
778<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]779@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]780</pre>
781</div>
782
783</div>
784
785
786<!-- ======================================================================= -->
787<div class="doc_subsection">
788 <a name="functionstructure">Functions</a>
789</div>
790
791<div class="doc_text">
792
793<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
794an optional <a href="#linkage">linkage type</a>, an optional
795<a href="#visibility">visibility style</a>, an optional
796<a href="#callingconv">calling convention</a>, a return type, an optional
797<a href="#paramattrs">parameter attribute</a> for the return type, a function
798name, a (possibly empty) argument list (each with optional
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]799<a href="#paramattrs">parameter attributes</a>), optional
800<a href="#fnattrs">function attributes</a>, an optional section,
801an optional alignment, an optional <a href="#gc">garbage collector name</a>,
Chris Lattneree202542008-10-04 18:10:21 +0000[diff] [blame]802an opening curly brace, a list of basic blocks, and a closing curly brace.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]803
804LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
805optional <a href="#linkage">linkage type</a>, an optional
806<a href="#visibility">visibility style</a>, an optional
807<a href="#callingconv">calling convention</a>, a return type, an optional
808<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]809name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksend606f5b2007-12-10 03:30:21 +0000[diff] [blame]810<a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]811
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]812<p>A function definition contains a list of basic blocks, forming the CFG
813(Control Flow Graph) for
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]814the function. Each basic block may optionally start with a label (giving the
815basic block a symbol table entry), contains a list of instructions, and ends
816with a <a href="#terminators">terminator</a> instruction (such as a branch or
817function return).</p>
818
819<p>The first basic block in a function is special in two ways: it is immediately
820executed on entrance to the function, and it is not allowed to have predecessor
821basic blocks (i.e. there can not be any branches to the entry block of a
822function). Because the block can have no predecessors, it also cannot have any
823<a href="#i_phi">PHI nodes</a>.</p>
824
825<p>LLVM allows an explicit section to be specified for functions. If the target
826supports it, it will emit functions to the section specified.</p>
827
828<p>An explicit alignment may be specified for a function. If not present, or if
829the alignment is set to zero, the alignment of the function is set by the target
830to whatever it feels convenient. If an explicit alignment is specified, the
831function is forced to have at least that much alignment. All alignments must be
832a power of 2.</p>
833
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]834 <h5>Syntax:</h5>
835
836<div class="doc_code">
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]837<tt>
838define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
839 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
840 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
841 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
842 [<a href="#gc">gc</a>] { ... }
843</tt>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]844</div>
845
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]846</div>
847
848
849<!-- ======================================================================= -->
850<div class="doc_subsection">
851 <a name="aliasstructure">Aliases</a>
852</div>
853<div class="doc_text">
854 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikov96822812008-03-22 08:36:14 +0000[diff] [blame]855 function, global variable, another alias or bitcast of global value). Aliases
856 may have an optional <a href="#linkage">linkage type</a>, and an
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]857 optional <a href="#visibility">visibility style</a>.</p>
858
859 <h5>Syntax:</h5>
860
861<div class="doc_code">
862<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]863@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]864</pre>
865</div>
866
867</div>
868
869
870
871<!-- ======================================================================= -->
872<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
873<div class="doc_text">
874 <p>The return type and each parameter of a function type may have a set of
875 <i>parameter attributes</i> associated with them. Parameter attributes are
876 used to communicate additional information about the result or parameters of
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]877 a function. Parameter attributes are considered to be part of the function,
878 not of the function type, so functions with different parameter attributes
879 can have the same function type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]880
881 <p>Parameter attributes are simple keywords that follow the type specified. If
882 multiple parameter attributes are needed, they are space separated. For
883 example:</p>
884
885<div class="doc_code">
886<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]887declare i32 @printf(i8* noalias , ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]888declare i32 @atoi(i8 zeroext)
889declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]890</pre>
891</div>
892
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]893 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
894 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]895
896 <p>Currently, only the following parameter attributes are defined:</p>
897 <dl>
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]898 <dt><tt>zeroext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]899 <dd>This indicates to the code generator that the parameter or return value
900 should be zero-extended to a 32-bit value by the caller (for a parameter)
901 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]902
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]903 <dt><tt>signext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]904 <dd>This indicates to the code generator that the parameter or return value
905 should be sign-extended to a 32-bit value by the caller (for a parameter)
906 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]907
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]908 <dt><tt>inreg</tt></dt>
Dale Johannesenc08a0e22008-09-25 20:47:45 +0000[diff] [blame]909 <dd>This indicates that this parameter or return value should be treated
910 in a special target-dependent fashion during while emitting code for a
911 function call or return (usually, by putting it in a register as opposed
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]912 to memory, though some targets use it to distinguish between two different
913 kinds of registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]914
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]915 <dt><tt><a name="byval">byval</a></tt></dt>
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]916 <dd>This indicates that the pointer parameter should really be passed by
917 value to the function. The attribute implies that a hidden copy of the
918 pointee is made between the caller and the callee, so the callee is unable
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]919 to modify the value in the callee. This attribute is only valid on LLVM
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]920 pointer arguments. It is generally used to pass structs and arrays by
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]921 value, but is also valid on pointers to scalars. The copy is considered to
922 belong to the caller not the callee (for example,
923 <tt><a href="#readonly">readonly</a></tt> functions should not write to
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]924 <tt>byval</tt> parameters). This is not a valid attribute for return
925 values. </dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]926
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]927 <dt><tt>sret</tt></dt>
Duncan Sands616cc032008-02-18 04:19:38 +0000[diff] [blame]928 <dd>This indicates that the pointer parameter specifies the address of a
929 structure that is the return value of the function in the source program.
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]930 This pointer must be guaranteed by the caller to be valid: loads and stores
931 to the structure may be assumed by the callee to not to trap. This may only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]932 be applied to the first parameter. This is not a valid attribute for
933 return values. </dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]934
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]935 <dt><tt>noalias</tt></dt>
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]936 <dd>This indicates that the pointer does not alias any global or any other
937 parameter. The caller is responsible for ensuring that this is the
Nick Lewyckya604a942008-11-24 05:00:44 +0000[diff] [blame]938 case. On a function return value, <tt>noalias</tt> additionally indicates
939 that the pointer does not alias any other pointers visible to the
Nick Lewycky40fb6f22008-12-19 06:39:12 +0000[diff] [blame]940 caller. For further details, please see the discussion of the NoAlias
941 response in
942 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
943 analysis</a>.</dd>
944
945 <dt><tt>nocapture</tt></dt>
946 <dd>This indicates that the callee does not make any copies of the pointer
947 that outlive the callee itself. This is not a valid attribute for return
948 values.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]949
Duncan Sands4ee46812007-07-27 19:57:41 +0000[diff] [blame]950 <dt><tt>nest</tt></dt>
Duncan Sandsf1a7d4c2008-07-08 09:27:25 +0000[diff] [blame]951 <dd>This indicates that the pointer parameter can be excised using the
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]952 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
953 attribute for return values.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]954 </dl>
955
956</div>
957
958<!-- ======================================================================= -->
959<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]960 <a name="gc">Garbage Collector Names</a>
961</div>
962
963<div class="doc_text">
964<p>Each function may specify a garbage collector name, which is simply a
965string.</p>
966
967<div class="doc_code"><pre
968>define void @f() gc "name" { ...</pre></div>
969
970<p>The compiler declares the supported values of <i>name</i>. Specifying a
971collector which will cause the compiler to alter its output in order to support
972the named garbage collection algorithm.</p>
973</div>
974
975<!-- ======================================================================= -->
976<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]977 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]978</div>
979
980<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]981
982<p>Function attributes are set to communicate additional information about
983 a function. Function attributes are considered to be part of the function,
984 not of the function type, so functions with different parameter attributes
985 can have the same function type.</p>
986
987 <p>Function attributes are simple keywords that follow the type specified. If
988 multiple attributes are needed, they are space separated. For
989 example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]990
991<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]992<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]993define void @f() noinline { ... }
994define void @f() alwaysinline { ... }
995define void @f() alwaysinline optsize { ... }
996define void @f() optsize
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]997</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]998</div>
999
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1000<dl>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1001<dt><tt>alwaysinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1002<dd>This attribute indicates that the inliner should attempt to inline this
1003function into callers whenever possible, ignoring any active inlining size
1004threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1005
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1006<dt><tt>noinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1007<dd>This attribute indicates that the inliner should never inline this function
Chris Lattner377f3ae2008-10-05 17:14:59 +0000[diff] [blame]1008in any situation. This attribute may not be used together with the
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1009<tt>alwaysinline</tt> attribute.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1010
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1011<dt><tt>optsize</tt></dt>
Devang Patelc29099b2008-09-29 18:34:44 +0000[diff] [blame]1012<dd>This attribute suggests that optimization passes and code generator passes
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1013make choices that keep the code size of this function low, and otherwise do
1014optimizations specifically to reduce code size.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1015
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1016<dt><tt>noreturn</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1017<dd>This function attribute indicates that the function never returns normally.
1018This produces undefined behavior at runtime if the function ever does
1019dynamically return.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1020
1021<dt><tt>nounwind</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1022<dd>This function attribute indicates that the function never returns with an
1023unwind or exceptional control flow. If the function does unwind, its runtime
1024behavior is undefined.</dd>
1025
1026<dt><tt>readnone</tt></dt>
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]1027<dd>This attribute indicates that the function computes its result (or the
1028exception it throws) based strictly on its arguments, without dereferencing any
1029pointer arguments or otherwise accessing any mutable state (e.g. memory, control
1030registers, etc) visible to caller functions. It does not write through any
1031pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments) and
1032never changes any state visible to callers.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1033
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]1034<dt><tt><a name="readonly">readonly</a></tt></dt>
1035<dd>This attribute indicates that the function does not write through any
1036pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments)
1037or otherwise modify any state (e.g. memory, control registers, etc) visible to
1038caller functions. It may dereference pointer arguments and read state that may
1039be set in the caller. A readonly function always returns the same value (or
1040throws the same exception) when called with the same set of arguments and global
1041state.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1042
1043<dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1044<dd>This attribute indicates that the function should emit a stack smashing
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1045protector. It is in the form of a "canary"&mdash;a random value placed on the
1046stack before the local variables that's checked upon return from the function to
1047see if it has been overwritten. A heuristic is used to determine if a function
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1048needs stack protectors or not.
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1049
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1050<p>If a function that has an <tt>ssp</tt> attribute is inlined into a function
1051that doesn't have an <tt>ssp</tt> attribute, then the resulting function will
1052have an <tt>ssp</tt> attribute.</p></dd>
1053
1054<dt><tt>sspreq</tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1055<dd>This attribute indicates that the function should <em>always</em> emit a
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1056stack smashing protector. This overrides the <tt><a href="#ssp">ssp</a></tt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1057function attribute.
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1058
1059<p>If a function that has an <tt>sspreq</tt> attribute is inlined into a
1060function that doesn't have an <tt>sspreq</tt> attribute or which has
1061an <tt>ssp</tt> attribute, then the resulting function will have
1062an <tt>sspreq</tt> attribute.</p></dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1063</dl>
1064
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1065</div>
1066
1067<!-- ======================================================================= -->
1068<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1069 <a name="moduleasm">Module-Level Inline Assembly</a>
1070</div>
1071
1072<div class="doc_text">
1073<p>
1074Modules may contain "module-level inline asm" blocks, which corresponds to the
1075GCC "file scope inline asm" blocks. These blocks are internally concatenated by
1076LLVM and treated as a single unit, but may be separated in the .ll file if
1077desired. The syntax is very simple:
1078</p>
1079
1080<div class="doc_code">
1081<pre>
1082module asm "inline asm code goes here"
1083module asm "more can go here"
1084</pre>
1085</div>
1086
1087<p>The strings can contain any character by escaping non-printable characters.
1088 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
1089 for the number.
1090</p>
1091
1092<p>
1093 The inline asm code is simply printed to the machine code .s file when
1094 assembly code is generated.
1095</p>
1096</div>
1097
1098<!-- ======================================================================= -->
1099<div class="doc_subsection">
1100 <a name="datalayout">Data Layout</a>
1101</div>
1102
1103<div class="doc_text">
1104<p>A module may specify a target specific data layout string that specifies how
1105data is to be laid out in memory. The syntax for the data layout is simply:</p>
1106<pre> target datalayout = "<i>layout specification</i>"</pre>
1107<p>The <i>layout specification</i> consists of a list of specifications
1108separated by the minus sign character ('-'). Each specification starts with a
1109letter and may include other information after the letter to define some
1110aspect of the data layout. The specifications accepted are as follows: </p>
1111<dl>
1112 <dt><tt>E</tt></dt>
1113 <dd>Specifies that the target lays out data in big-endian form. That is, the
1114 bits with the most significance have the lowest address location.</dd>
1115 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1116 <dd>Specifies that the target lays out data in little-endian form. That is,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1117 the bits with the least significance have the lowest address location.</dd>
1118 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1119 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
1120 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
1121 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
1122 too.</dd>
1123 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1124 <dd>This specifies the alignment for an integer type of a given bit
1125 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1126 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1127 <dd>This specifies the alignment for a vector type of a given bit
1128 <i>size</i>.</dd>
1129 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1130 <dd>This specifies the alignment for a floating point type of a given bit
1131 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1132 (double).</dd>
1133 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1134 <dd>This specifies the alignment for an aggregate type of a given bit
1135 <i>size</i>.</dd>
1136</dl>
1137<p>When constructing the data layout for a given target, LLVM starts with a
1138default set of specifications which are then (possibly) overriden by the
1139specifications in the <tt>datalayout</tt> keyword. The default specifications
1140are given in this list:</p>
1141<ul>
1142 <li><tt>E</tt> - big endian</li>
1143 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1144 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1145 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1146 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1147 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1148 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1149 alignment of 64-bits</li>
1150 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1151 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1152 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1153 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1154 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
1155</ul>
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]1156<p>When LLVM is determining the alignment for a given type, it uses the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1157following rules:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1158<ol>
1159 <li>If the type sought is an exact match for one of the specifications, that
1160 specification is used.</li>
1161 <li>If no match is found, and the type sought is an integer type, then the
1162 smallest integer type that is larger than the bitwidth of the sought type is
1163 used. If none of the specifications are larger than the bitwidth then the the
1164 largest integer type is used. For example, given the default specifications
1165 above, the i7 type will use the alignment of i8 (next largest) while both
1166 i65 and i256 will use the alignment of i64 (largest specified).</li>
1167 <li>If no match is found, and the type sought is a vector type, then the
1168 largest vector type that is smaller than the sought vector type will be used
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1169 as a fall back. This happens because &lt;128 x double&gt; can be implemented
1170 in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1171</ol>
1172</div>
1173
1174<!-- *********************************************************************** -->
1175<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1176<!-- *********************************************************************** -->
1177
1178<div class="doc_text">
1179
1180<p>The LLVM type system is one of the most important features of the
1181intermediate representation. Being typed enables a number of
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1182optimizations to be performed on the intermediate representation directly,
1183without having to do
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1184extra analyses on the side before the transformation. A strong type
1185system makes it easier to read the generated code and enables novel
1186analyses and transformations that are not feasible to perform on normal
1187three address code representations.</p>
1188
1189</div>
1190
1191<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1192<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1193Classifications</a> </div>
1194<div class="doc_text">
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1195<p>The types fall into a few useful
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1196classifications:</p>
1197
1198<table border="1" cellspacing="0" cellpadding="4">
1199 <tbody>
1200 <tr><th>Classification</th><th>Types</th></tr>
1201 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1202 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1203 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1204 </tr>
1205 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1206 <td><a href="#t_floating">floating point</a></td>
1207 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1208 </tr>
1209 <tr>
1210 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1211 <td><a href="#t_integer">integer</a>,
1212 <a href="#t_floating">floating point</a>,
1213 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1214 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1215 <a href="#t_struct">structure</a>,
1216 <a href="#t_array">array</a>,
Dan Gohmand13951e2008-05-23 22:50:26 +0000[diff] [blame]1217 <a href="#t_label">label</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1218 </td>
1219 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1220 <tr>
1221 <td><a href="#t_primitive">primitive</a></td>
1222 <td><a href="#t_label">label</a>,
1223 <a href="#t_void">void</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1224 <a href="#t_floating">floating point</a>.</td>
1225 </tr>
1226 <tr>
1227 <td><a href="#t_derived">derived</a></td>
1228 <td><a href="#t_integer">integer</a>,
1229 <a href="#t_array">array</a>,
1230 <a href="#t_function">function</a>,
1231 <a href="#t_pointer">pointer</a>,
1232 <a href="#t_struct">structure</a>,
1233 <a href="#t_pstruct">packed structure</a>,
1234 <a href="#t_vector">vector</a>,
1235 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1236 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1237 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1238 </tbody>
1239</table>
1240
1241<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1242most important. Values of these types are the only ones which can be
1243produced by instructions, passed as arguments, or used as operands to
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]1244instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1245</div>
1246
1247<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1248<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1249
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1250<div class="doc_text">
1251<p>The primitive types are the fundamental building blocks of the LLVM
1252system.</p>
1253
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1254</div>
1255
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1256<!-- _______________________________________________________________________ -->
1257<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1258
1259<div class="doc_text">
1260 <table>
1261 <tbody>
1262 <tr><th>Type</th><th>Description</th></tr>
1263 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1264 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1265 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1266 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1267 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1268 </tbody>
1269 </table>
1270</div>
1271
1272<!-- _______________________________________________________________________ -->
1273<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1274
1275<div class="doc_text">
1276<h5>Overview:</h5>
1277<p>The void type does not represent any value and has no size.</p>
1278
1279<h5>Syntax:</h5>
1280
1281<pre>
1282 void
1283</pre>
1284</div>
1285
1286<!-- _______________________________________________________________________ -->
1287<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1288
1289<div class="doc_text">
1290<h5>Overview:</h5>
1291<p>The label type represents code labels.</p>
1292
1293<h5>Syntax:</h5>
1294
1295<pre>
1296 label
1297</pre>
1298</div>
1299
1300
1301<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1302<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1303
1304<div class="doc_text">
1305
1306<p>The real power in LLVM comes from the derived types in the system.
1307This is what allows a programmer to represent arrays, functions,
1308pointers, and other useful types. Note that these derived types may be
1309recursive: For example, it is possible to have a two dimensional array.</p>
1310
1311</div>
1312
1313<!-- _______________________________________________________________________ -->
1314<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1315
1316<div class="doc_text">
1317
1318<h5>Overview:</h5>
1319<p>The integer type is a very simple derived type that simply specifies an
1320arbitrary bit width for the integer type desired. Any bit width from 1 bit to
13212^23-1 (about 8 million) can be specified.</p>
1322
1323<h5>Syntax:</h5>
1324
1325<pre>
1326 iN
1327</pre>
1328
1329<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1330value.</p>
1331
1332<h5>Examples:</h5>
1333<table class="layout">
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1334 <tbody>
1335 <tr>
1336 <td><tt>i1</tt></td>
1337 <td>a single-bit integer.</td>
1338 </tr><tr>
1339 <td><tt>i32</tt></td>
1340 <td>a 32-bit integer.</td>
1341 </tr><tr>
1342 <td><tt>i1942652</tt></td>
1343 <td>a really big integer of over 1 million bits.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1344 </tr>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1345 </tbody>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1346</table>
1347</div>
1348
1349<!-- _______________________________________________________________________ -->
1350<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1351
1352<div class="doc_text">
1353
1354<h5>Overview:</h5>
1355
1356<p>The array type is a very simple derived type that arranges elements
1357sequentially in memory. The array type requires a size (number of
1358elements) and an underlying data type.</p>
1359
1360<h5>Syntax:</h5>
1361
1362<pre>
1363 [&lt;# elements&gt; x &lt;elementtype&gt;]
1364</pre>
1365
1366<p>The number of elements is a constant integer value; elementtype may
1367be any type with a size.</p>
1368
1369<h5>Examples:</h5>
1370<table class="layout">
1371 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1372 <td class="left"><tt>[40 x i32]</tt></td>
1373 <td class="left">Array of 40 32-bit integer values.</td>
1374 </tr>
1375 <tr class="layout">
1376 <td class="left"><tt>[41 x i32]</tt></td>
1377 <td class="left">Array of 41 32-bit integer values.</td>
1378 </tr>
1379 <tr class="layout">
1380 <td class="left"><tt>[4 x i8]</tt></td>
1381 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1382 </tr>
1383</table>
1384<p>Here are some examples of multidimensional arrays:</p>
1385<table class="layout">
1386 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1387 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1388 <td class="left">3x4 array of 32-bit integer values.</td>
1389 </tr>
1390 <tr class="layout">
1391 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1392 <td class="left">12x10 array of single precision floating point values.</td>
1393 </tr>
1394 <tr class="layout">
1395 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1396 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1397 </tr>
1398</table>
1399
1400<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1401length array. Normally, accesses past the end of an array are undefined in
1402LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1403As a special case, however, zero length arrays are recognized to be variable
1404length. This allows implementation of 'pascal style arrays' with the LLVM
1405type "{ i32, [0 x float]}", for example.</p>
1406
1407</div>
1408
1409<!-- _______________________________________________________________________ -->
1410<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
1411<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1412
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1413<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1414
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1415<p>The function type can be thought of as a function signature. It
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1416consists of a return type and a list of formal parameter types. The
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1417return 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]1418If 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]1419class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1420
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1421<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1422
1423<pre>
1424 &lt;returntype list&gt; (&lt;parameter list&gt;)
1425</pre>
1426
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1427<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
1428specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1429which indicates that the function takes a variable number of arguments.
1430Variable argument functions can access their arguments with the <a
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1431 href="#int_varargs">variable argument handling intrinsic</a> functions.
1432'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1433<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1434
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1435<h5>Examples:</h5>
1436<table class="layout">
1437 <tr class="layout">
1438 <td class="left"><tt>i32 (i32)</tt></td>
1439 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1440 </td>
1441 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1442 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1443 </tt></td>
1444 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1445 an <tt>i16</tt> that should be sign extended and a
1446 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1447 <tt>float</tt>.
1448 </td>
1449 </tr><tr class="layout">
1450 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1451 <td class="left">A vararg function that takes at least one
1452 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1453 which returns an integer. This is the signature for <tt>printf</tt> in
1454 LLVM.
1455 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1456 </tr><tr class="layout">
1457 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Misha Brukmanafc88b02008-11-27 06:41:20 +0000[diff] [blame]1458 <td class="left">A function taking an <tt>i32</tt>, returning two
1459 <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1460 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1461 </tr>
1462</table>
1463
1464</div>
1465<!-- _______________________________________________________________________ -->
1466<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
1467<div class="doc_text">
1468<h5>Overview:</h5>
1469<p>The structure type is used to represent a collection of data members
1470together in memory. The packing of the field types is defined to match
1471the ABI of the underlying processor. The elements of a structure may
1472be any type that has a size.</p>
1473<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1474and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1475field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1476instruction.</p>
1477<h5>Syntax:</h5>
1478<pre> { &lt;type list&gt; }<br></pre>
1479<h5>Examples:</h5>
1480<table class="layout">
1481 <tr class="layout">
1482 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1483 <td class="left">A triple of three <tt>i32</tt> values</td>
1484 </tr><tr class="layout">
1485 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1486 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1487 second element is a <a href="#t_pointer">pointer</a> to a
1488 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1489 an <tt>i32</tt>.</td>
1490 </tr>
1491</table>
1492</div>
1493
1494<!-- _______________________________________________________________________ -->
1495<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1496</div>
1497<div class="doc_text">
1498<h5>Overview:</h5>
1499<p>The packed structure type is used to represent a collection of data members
1500together in memory. There is no padding between fields. Further, the alignment
1501of a packed structure is 1 byte. The elements of a packed structure may
1502be any type that has a size.</p>
1503<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1504and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1505field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1506instruction.</p>
1507<h5>Syntax:</h5>
1508<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1509<h5>Examples:</h5>
1510<table class="layout">
1511 <tr class="layout">
1512 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1513 <td class="left">A triple of three <tt>i32</tt> values</td>
1514 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1515 <td class="left">
1516<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1517 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1518 second element is a <a href="#t_pointer">pointer</a> to a
1519 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1520 an <tt>i32</tt>.</td>
1521 </tr>
1522</table>
1523</div>
1524
1525<!-- _______________________________________________________________________ -->
1526<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
1527<div class="doc_text">
1528<h5>Overview:</h5>
1529<p>As in many languages, the pointer type represents a pointer or
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]1530reference to another object, which must live in memory. Pointer types may have
1531an optional address space attribute defining the target-specific numbered
1532address space where the pointed-to object resides. The default address space is
1533zero.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1534<h5>Syntax:</h5>
1535<pre> &lt;type&gt; *<br></pre>
1536<h5>Examples:</h5>
1537<table class="layout">
1538 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1539 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1540 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1541 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1542 </tr>
1543 <tr class="layout">
1544 <td class="left"><tt>i32 (i32 *) *</tt></td>
1545 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1546 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1547 <tt>i32</tt>.</td>
1548 </tr>
1549 <tr class="layout">
1550 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1551 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1552 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1553 </tr>
1554</table>
1555</div>
1556
1557<!-- _______________________________________________________________________ -->
1558<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
1559<div class="doc_text">
1560
1561<h5>Overview:</h5>
1562
1563<p>A vector type is a simple derived type that represents a vector
1564of elements. Vector types are used when multiple primitive data
1565are operated in parallel using a single instruction (SIMD).
1566A vector type requires a size (number of
1567elements) and an underlying primitive data type. Vectors must have a power
1568of two length (1, 2, 4, 8, 16 ...). Vector types are
1569considered <a href="#t_firstclass">first class</a>.</p>
1570
1571<h5>Syntax:</h5>
1572
1573<pre>
1574 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1575</pre>
1576
1577<p>The number of elements is a constant integer value; elementtype may
1578be any integer or floating point type.</p>
1579
1580<h5>Examples:</h5>
1581
1582<table class="layout">
1583 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1584 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1585 <td class="left">Vector of 4 32-bit integer values.</td>
1586 </tr>
1587 <tr class="layout">
1588 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1589 <td class="left">Vector of 8 32-bit floating-point values.</td>
1590 </tr>
1591 <tr class="layout">
1592 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1593 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1594 </tr>
1595</table>
1596</div>
1597
1598<!-- _______________________________________________________________________ -->
1599<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1600<div class="doc_text">
1601
1602<h5>Overview:</h5>
1603
1604<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksenda0706e2007-10-14 00:34:53 +0000[diff] [blame]1605corresponds (for example) to the C notion of a forward declared structure type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1606In LLVM, opaque types can eventually be resolved to any type (not just a
1607structure type).</p>
1608
1609<h5>Syntax:</h5>
1610
1611<pre>
1612 opaque
1613</pre>
1614
1615<h5>Examples:</h5>
1616
1617<table class="layout">
1618 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1619 <td class="left"><tt>opaque</tt></td>
1620 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1621 </tr>
1622</table>
1623</div>
1624
1625
1626<!-- *********************************************************************** -->
1627<div class="doc_section"> <a name="constants">Constants</a> </div>
1628<!-- *********************************************************************** -->
1629
1630<div class="doc_text">
1631
1632<p>LLVM has several different basic types of constants. This section describes
1633them all and their syntax.</p>
1634
1635</div>
1636
1637<!-- ======================================================================= -->
1638<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1639
1640<div class="doc_text">
1641
1642<dl>
1643 <dt><b>Boolean constants</b></dt>
1644
1645 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1646 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
1647 </dd>
1648
1649 <dt><b>Integer constants</b></dt>
1650
1651 <dd>Standard integers (such as '4') are constants of the <a
1652 href="#t_integer">integer</a> type. Negative numbers may be used with
1653 integer types.
1654 </dd>
1655
1656 <dt><b>Floating point constants</b></dt>
1657
1658 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1659 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]1660 notation (see below). The assembler requires the exact decimal value of
1661 a floating-point constant. For example, the assembler accepts 1.25 but
1662 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1663 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1664
1665 <dt><b>Null pointer constants</b></dt>
1666
1667 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
1668 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1669
1670</dl>
1671
1672<p>The one non-intuitive notation for constants is the optional hexadecimal form
1673of floating point constants. For example, the form '<tt>double
16740x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
16754.5e+15</tt>'. The only time hexadecimal floating point constants are required
1676(and the only time that they are generated by the disassembler) is when a
1677floating point constant must be emitted but it cannot be represented as a
1678decimal floating point number. For example, NaN's, infinities, and other
1679special values are represented in their IEEE hexadecimal format so that
1680assembly and disassembly do not cause any bits to change in the constants.</p>
1681
1682</div>
1683
1684<!-- ======================================================================= -->
1685<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1686</div>
1687
1688<div class="doc_text">
1689<p>Aggregate constants arise from aggregation of simple constants
1690and smaller aggregate constants.</p>
1691
1692<dl>
1693 <dt><b>Structure constants</b></dt>
1694
1695 <dd>Structure constants are represented with notation similar to structure
1696 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner6c8de962007-12-25 20:34:52 +0000[diff] [blame]1697 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1698 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]1699 must have <a href="#t_struct">structure type</a>, and the number and
1700 types of elements must match those specified by the type.
1701 </dd>
1702
1703 <dt><b>Array constants</b></dt>
1704
1705 <dd>Array constants are represented with notation similar to array type
1706 definitions (a comma separated list of elements, surrounded by square brackets
1707 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
1708 constants must have <a href="#t_array">array type</a>, and the number and
1709 types of elements must match those specified by the type.
1710 </dd>
1711
1712 <dt><b>Vector constants</b></dt>
1713
1714 <dd>Vector constants are represented with notation similar to vector type
1715 definitions (a comma separated list of elements, surrounded by
1716 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1717 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
1718 href="#t_vector">vector type</a>, and the number and types of elements must
1719 match those specified by the type.
1720 </dd>
1721
1722 <dt><b>Zero initialization</b></dt>
1723
1724 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1725 value to zero of <em>any</em> type, including scalar and aggregate types.
1726 This is often used to avoid having to print large zero initializers (e.g. for
1727 large arrays) and is always exactly equivalent to using explicit zero
1728 initializers.
1729 </dd>
1730</dl>
1731
1732</div>
1733
1734<!-- ======================================================================= -->
1735<div class="doc_subsection">
1736 <a name="globalconstants">Global Variable and Function Addresses</a>
1737</div>
1738
1739<div class="doc_text">
1740
1741<p>The addresses of <a href="#globalvars">global variables</a> and <a
1742href="#functionstructure">functions</a> are always implicitly valid (link-time)
1743constants. These constants are explicitly referenced when the <a
1744href="#identifiers">identifier for the global</a> is used and always have <a
1745href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1746file:</p>
1747
1748<div class="doc_code">
1749<pre>
1750@X = global i32 17
1751@Y = global i32 42
1752@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
1753</pre>
1754</div>
1755
1756</div>
1757
1758<!-- ======================================================================= -->
1759<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
1760<div class="doc_text">
1761 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
1762 no specific value. Undefined values may be of any type and be used anywhere
1763 a constant is permitted.</p>
1764
1765 <p>Undefined values indicate to the compiler that the program is well defined
1766 no matter what value is used, giving the compiler more freedom to optimize.
1767 </p>
1768</div>
1769
1770<!-- ======================================================================= -->
1771<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1772</div>
1773
1774<div class="doc_text">
1775
1776<p>Constant expressions are used to allow expressions involving other constants
1777to be used as constants. Constant expressions may be of any <a
1778href="#t_firstclass">first class</a> type and may involve any LLVM operation
1779that does not have side effects (e.g. load and call are not supported). The
1780following is the syntax for constant expressions:</p>
1781
1782<dl>
1783 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1784 <dd>Truncate a constant to another type. The bit size of CST must be larger
1785 than the bit size of TYPE. Both types must be integers.</dd>
1786
1787 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1788 <dd>Zero extend a constant to another type. The bit size of CST must be
1789 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1790
1791 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1792 <dd>Sign extend a constant to another type. The bit size of CST must be
1793 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1794
1795 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1796 <dd>Truncate a floating point constant to another floating point type. The
1797 size of CST must be larger than the size of TYPE. Both types must be
1798 floating point.</dd>
1799
1800 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1801 <dd>Floating point extend a constant to another type. The size of CST must be
1802 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1803
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]1804 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1805 <dd>Convert a floating point constant to the corresponding unsigned 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>fptosi ( CST to TYPE )</tt></b></dt>
1812 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1813 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1814 or vector floating point 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 integer type,
1816 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1817
1818 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
1819 <dd>Convert an unsigned 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>sitofp ( CST to TYPE )</tt></b></dt>
1826 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1827 constant. TYPE must be a scalar or vector floating point type. CST must be of
1828 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1829 of the same number of elements. If the value won't fit in the floating point
1830 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1831
1832 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1833 <dd>Convert a pointer typed constant to the corresponding integer constant
1834 TYPE must be an integer type. CST must be of pointer type. The CST value is
1835 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1836
1837 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1838 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1839 pointer type. CST must be of integer type. The CST value is zero extended,
1840 truncated, or unchanged to make it fit in a pointer size. This one is
1841 <i>really</i> dangerous!</dd>
1842
1843 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
1844 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1845 identical (same number of bits). The conversion is done as if the CST value
1846 was stored to memory and read back as TYPE. In other words, no bits change
1847 with this operator, just the type. This can be used for conversion of
1848 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]1849 pointers it is only valid to cast to another pointer type. It is not valid
1850 to bitcast to or from an aggregate type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1851 </dd>
1852
1853 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1854
1855 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1856 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1857 instruction, the index list may have zero or more indexes, which are required
1858 to make sense for the type of "CSTPTR".</dd>
1859
1860 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1861
1862 <dd>Perform the <a href="#i_select">select operation</a> on
1863 constants.</dd>
1864
1865 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1866 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1867
1868 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1869 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
1870
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]1871 <dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
1872 <dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
1873
1874 <dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
1875 <dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
1876
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1877 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1878
1879 <dd>Perform the <a href="#i_extractelement">extractelement
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1880 operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1881
1882 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1883
1884 <dd>Perform the <a href="#i_insertelement">insertelement
1885 operation</a> on constants.</dd>
1886
1887
1888 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1889
1890 <dd>Perform the <a href="#i_shufflevector">shufflevector
1891 operation</a> on constants.</dd>
1892
1893 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1894
1895 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1896 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
1897 binary</a> operations. The constraints on operands are the same as those for
1898 the corresponding instruction (e.g. no bitwise operations on floating point
1899 values are allowed).</dd>
1900</dl>
1901</div>
1902
1903<!-- *********************************************************************** -->
1904<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1905<!-- *********************************************************************** -->
1906
1907<!-- ======================================================================= -->
1908<div class="doc_subsection">
1909<a name="inlineasm">Inline Assembler Expressions</a>
1910</div>
1911
1912<div class="doc_text">
1913
1914<p>
1915LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1916Module-Level Inline Assembly</a>) through the use of a special value. This
1917value represents the inline assembler as a string (containing the instructions
1918to emit), a list of operand constraints (stored as a string), and a flag that
1919indicates whether or not the inline asm expression has side effects. An example
1920inline assembler expression is:
1921</p>
1922
1923<div class="doc_code">
1924<pre>
1925i32 (i32) asm "bswap $0", "=r,r"
1926</pre>
1927</div>
1928
1929<p>
1930Inline assembler expressions may <b>only</b> be used as the callee operand of
1931a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1932</p>
1933
1934<div class="doc_code">
1935<pre>
1936%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
1937</pre>
1938</div>
1939
1940<p>
1941Inline asms with side effects not visible in the constraint list must be marked
1942as having side effects. This is done through the use of the
1943'<tt>sideeffect</tt>' keyword, like so:
1944</p>
1945
1946<div class="doc_code">
1947<pre>
1948call void asm sideeffect "eieio", ""()
1949</pre>
1950</div>
1951
1952<p>TODO: The format of the asm and constraints string still need to be
1953documented here. Constraints on what can be done (e.g. duplication, moving, etc
Chris Lattner1cdd64e2008-10-04 18:36:02 +0000[diff] [blame]1954need to be documented). This is probably best done by reference to another
1955document that covers inline asm from a holistic perspective.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1956</p>
1957
1958</div>
1959
1960<!-- *********************************************************************** -->
1961<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1962<!-- *********************************************************************** -->
1963
1964<div class="doc_text">
1965
1966<p>The LLVM instruction set consists of several different
1967classifications of instructions: <a href="#terminators">terminator
1968instructions</a>, <a href="#binaryops">binary instructions</a>,
1969<a href="#bitwiseops">bitwise binary instructions</a>, <a
1970 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1971instructions</a>.</p>
1972
1973</div>
1974
1975<!-- ======================================================================= -->
1976<div class="doc_subsection"> <a name="terminators">Terminator
1977Instructions</a> </div>
1978
1979<div class="doc_text">
1980
1981<p>As mentioned <a href="#functionstructure">previously</a>, every
1982basic block in a program ends with a "Terminator" instruction, which
1983indicates which block should be executed after the current block is
1984finished. These terminator instructions typically yield a '<tt>void</tt>'
1985value: they produce control flow, not values (the one exception being
1986the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
1987<p>There are six different terminator instructions: the '<a
1988 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1989instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
1990the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1991 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1992 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
1993
1994</div>
1995
1996<!-- _______________________________________________________________________ -->
1997<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1998Instruction</a> </div>
1999<div class="doc_text">
2000<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2001<pre>
2002 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]2003 ret void <i>; Return from void function</i>
2004</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2005
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2006<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2007
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2008<p>The '<tt>ret</tt>' instruction is used to return control flow (and
2009optionally a value) from a function back to the caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2010<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2011returns a value and then causes control flow, and one that just causes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2012control flow to occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2013
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2014<h5>Arguments:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2015
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2016<p>The '<tt>ret</tt>' instruction optionally accepts a single argument,
2017the return value. The type of the return value must be a
2018'<a href="#t_firstclass">first class</a>' type.</p>
2019
2020<p>A function is not <a href="#wellformed">well formed</a> if
2021it it has a non-void return type and contains a '<tt>ret</tt>'
2022instruction with no return value or a return value with a type that
2023does not match its type, or if it has a void return type and contains
2024a '<tt>ret</tt>' instruction with a return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2025
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2026<h5>Semantics:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2027
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2028<p>When the '<tt>ret</tt>' instruction is executed, control flow
2029returns back to the calling function's context. If the caller is a "<a
2030 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
2031the instruction after the call. If the caller was an "<a
2032 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
2033at the beginning of the "normal" destination block. If the instruction
2034returns a value, that value shall set the call or invoke instruction's
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2035return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2036
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2037<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2038
2039<pre>
2040 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2041 ret void <i>; Return from a void function</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2042 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]2043</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2044
2045<p>Note that the code generator does not yet fully support larger
2046 aggregate return values.</p>
2047
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2048</div>
2049<!-- _______________________________________________________________________ -->
2050<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
2051<div class="doc_text">
2052<h5>Syntax:</h5>
2053<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
2054</pre>
2055<h5>Overview:</h5>
2056<p>The '<tt>br</tt>' instruction is used to cause control flow to
2057transfer to a different basic block in the current function. There are
2058two forms of this instruction, corresponding to a conditional branch
2059and an unconditional branch.</p>
2060<h5>Arguments:</h5>
2061<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
2062single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
2063unconditional form of the '<tt>br</tt>' instruction takes a single
2064'<tt>label</tt>' value as a target.</p>
2065<h5>Semantics:</h5>
2066<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
2067argument is evaluated. If the value is <tt>true</tt>, control flows
2068to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2069control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2070<h5>Example:</h5>
2071<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
2072 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
2073</div>
2074<!-- _______________________________________________________________________ -->
2075<div class="doc_subsubsection">
2076 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2077</div>
2078
2079<div class="doc_text">
2080<h5>Syntax:</h5>
2081
2082<pre>
2083 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2084</pre>
2085
2086<h5>Overview:</h5>
2087
2088<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
2089several different places. It is a generalization of the '<tt>br</tt>'
2090instruction, allowing a branch to occur to one of many possible
2091destinations.</p>
2092
2093
2094<h5>Arguments:</h5>
2095
2096<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
2097comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
2098an array of pairs of comparison value constants and '<tt>label</tt>'s. The
2099table is not allowed to contain duplicate constant entries.</p>
2100
2101<h5>Semantics:</h5>
2102
2103<p>The <tt>switch</tt> instruction specifies a table of values and
2104destinations. When the '<tt>switch</tt>' instruction is executed, this
2105table is searched for the given value. If the value is found, control flow is
2106transfered to the corresponding destination; otherwise, control flow is
2107transfered to the default destination.</p>
2108
2109<h5>Implementation:</h5>
2110
2111<p>Depending on properties of the target machine and the particular
2112<tt>switch</tt> instruction, this instruction may be code generated in different
2113ways. For example, it could be generated as a series of chained conditional
2114branches or with a lookup table.</p>
2115
2116<h5>Example:</h5>
2117
2118<pre>
2119 <i>; Emulate a conditional br instruction</i>
2120 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2121 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2122
2123 <i>; Emulate an unconditional br instruction</i>
2124 switch i32 0, label %dest [ ]
2125
2126 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2127 switch i32 %val, label %otherwise [ i32 0, label %onzero
2128 i32 1, label %onone
2129 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2130</pre>
2131</div>
2132
2133<!-- _______________________________________________________________________ -->
2134<div class="doc_subsubsection">
2135 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2136</div>
2137
2138<div class="doc_text">
2139
2140<h5>Syntax:</h5>
2141
2142<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2143 &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]2144 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2145</pre>
2146
2147<h5>Overview:</h5>
2148
2149<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
2150function, with the possibility of control flow transfer to either the
2151'<tt>normal</tt>' label or the
2152'<tt>exception</tt>' label. If the callee function returns with the
2153"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
2154"normal" label. If the callee (or any indirect callees) returns with the "<a
2155href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2156continued at the dynamically nearest "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2157
2158<h5>Arguments:</h5>
2159
2160<p>This instruction requires several arguments:</p>
2161
2162<ol>
2163 <li>
2164 The optional "cconv" marker indicates which <a href="#callingconv">calling
2165 convention</a> the call should use. If none is specified, the call defaults
2166 to using C calling conventions.
2167 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2168
2169 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
2170 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
2171 and '<tt>inreg</tt>' attributes are valid here.</li>
2172
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2173 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
2174 function value being invoked. In most cases, this is a direct function
2175 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
2176 an arbitrary pointer to function value.
2177 </li>
2178
2179 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
2180 function to be invoked. </li>
2181
2182 <li>'<tt>function args</tt>': argument list whose types match the function
2183 signature argument types. If the function signature indicates the function
2184 accepts a variable number of arguments, the extra arguments can be
2185 specified. </li>
2186
2187 <li>'<tt>normal label</tt>': the label reached when the called function
2188 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2189
2190 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2191 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2192
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2193 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2194 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2195 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2196</ol>
2197
2198<h5>Semantics:</h5>
2199
2200<p>This instruction is designed to operate as a standard '<tt><a
2201href="#i_call">call</a></tt>' instruction in most regards. The primary
2202difference is that it establishes an association with a label, which is used by
2203the runtime library to unwind the stack.</p>
2204
2205<p>This instruction is used in languages with destructors to ensure that proper
2206cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2207exception. Additionally, this is important for implementation of
2208'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2209
2210<h5>Example:</h5>
2211<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2212 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2213 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2214 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2215 unwind label %TestCleanup <i>; {i32}:retval set</i>
2216</pre>
2217</div>
2218
2219
2220<!-- _______________________________________________________________________ -->
2221
2222<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2223Instruction</a> </div>
2224
2225<div class="doc_text">
2226
2227<h5>Syntax:</h5>
2228<pre>
2229 unwind
2230</pre>
2231
2232<h5>Overview:</h5>
2233
2234<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2235at the first callee in the dynamic call stack which used an <a
2236href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2237primarily used to implement exception handling.</p>
2238
2239<h5>Semantics:</h5>
2240
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2241<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2242immediately halt. The dynamic call stack is then searched for the first <a
2243href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2244execution continues at the "exceptional" destination block specified by the
2245<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2246dynamic call chain, undefined behavior results.</p>
2247</div>
2248
2249<!-- _______________________________________________________________________ -->
2250
2251<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2252Instruction</a> </div>
2253
2254<div class="doc_text">
2255
2256<h5>Syntax:</h5>
2257<pre>
2258 unreachable
2259</pre>
2260
2261<h5>Overview:</h5>
2262
2263<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2264instruction is used to inform the optimizer that a particular portion of the
2265code is not reachable. This can be used to indicate that the code after a
2266no-return function cannot be reached, and other facts.</p>
2267
2268<h5>Semantics:</h5>
2269
2270<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2271</div>
2272
2273
2274
2275<!-- ======================================================================= -->
2276<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
2277<div class="doc_text">
2278<p>Binary operators are used to do most of the computation in a
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2279program. They require two operands of the same type, execute an operation on them, and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2280produce a single value. The operands might represent
2281multiple 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]2282The result value has the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2283<p>There are several different binary operators:</p>
2284</div>
2285<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2286<div class="doc_subsubsection">
2287 <a name="i_add">'<tt>add</tt>' Instruction</a>
2288</div>
2289
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2290<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2291
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2292<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2293
2294<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2295 &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]2296</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2297
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2298<h5>Overview:</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 '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2301
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2302<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2303
2304<p>The two arguments to the '<tt>add</tt>' instruction must be <a
2305 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
2306 <a href="#t_vector">vector</a> values. Both arguments must have identical
2307 types.</p>
2308
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2309<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2310
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2311<p>The value produced is the integer or floating point sum of the two
2312operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2313
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2314<p>If an integer sum has unsigned overflow, the result returned is the
2315mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2316the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2317
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2318<p>Because LLVM integers use a two's complement representation, this
2319instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2320
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2321<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2322
2323<pre>
2324 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2325</pre>
2326</div>
2327<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2328<div class="doc_subsubsection">
2329 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2330</div>
2331
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2332<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2333
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2334<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2335
2336<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2337 &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]2338</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2339
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2340<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2341
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2342<p>The '<tt>sub</tt>' instruction returns the difference of its two
2343operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2344
2345<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2346'<tt>neg</tt>' instruction present in most other intermediate
2347representations.</p>
2348
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2349<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2350
2351<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
2352 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2353 or <a href="#t_vector">vector</a> values. Both arguments must have identical
2354 types.</p>
2355
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2356<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2357
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2358<p>The value produced is the integer or floating point difference of
2359the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2360
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2361<p>If an integer difference has unsigned overflow, the result returned is the
2362mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2363the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2364
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2365<p>Because LLVM integers use a two's complement representation, this
2366instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2367
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2368<h5>Example:</h5>
2369<pre>
2370 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2371 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2372</pre>
2373</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2374
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2375<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2376<div class="doc_subsubsection">
2377 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2378</div>
2379
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2380<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2381
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2382<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2383<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]2384</pre>
2385<h5>Overview:</h5>
2386<p>The '<tt>mul</tt>' instruction returns the product of its two
2387operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2388
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2389<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2390
2391<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
2392href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2393or <a href="#t_vector">vector</a> values. Both arguments must have identical
2394types.</p>
2395
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2396<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2397
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2398<p>The value produced is the integer or floating point product of the
2399two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2400
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2401<p>If the result of an integer multiplication has unsigned overflow,
2402the result returned is the mathematical result modulo
24032<sup>n</sup>, where n is the bit width of the result.</p>
2404<p>Because LLVM integers use a two's complement representation, and the
2405result is the same width as the operands, this instruction returns the
2406correct result for both signed and unsigned integers. If a full product
2407(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2408should be sign-extended or zero-extended as appropriate to the
2409width of the full product.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2410<h5>Example:</h5>
2411<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
2412</pre>
2413</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2414
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2415<!-- _______________________________________________________________________ -->
2416<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2417</a></div>
2418<div class="doc_text">
2419<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2420<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]2421</pre>
2422<h5>Overview:</h5>
2423<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2424operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2425
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2426<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2427
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2428<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2429<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2430values. Both arguments must have identical types.</p>
2431
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2432<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2433
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2434<p>The value produced is the unsigned integer quotient of the two operands.</p>
2435<p>Note that unsigned integer division and signed integer division are distinct
2436operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2437<p>Division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2438<h5>Example:</h5>
2439<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2440</pre>
2441</div>
2442<!-- _______________________________________________________________________ -->
2443<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2444</a> </div>
2445<div class="doc_text">
2446<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2447<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2448 &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]2449</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2450
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2451<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2452
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2453<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2454operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2455
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2456<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2457
2458<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2459<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2460values. Both arguments must have identical types.</p>
2461
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2462<h5>Semantics:</h5>
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2463<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]2464<p>Note that signed integer division and unsigned integer division are distinct
2465operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2466<p>Division by zero leads to undefined behavior. Overflow also leads to
2467undefined behavior; this is a rare case, but can occur, for example,
2468by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2469<h5>Example:</h5>
2470<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2471</pre>
2472</div>
2473<!-- _______________________________________________________________________ -->
2474<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2475Instruction</a> </div>
2476<div class="doc_text">
2477<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2478<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2479 &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]2480</pre>
2481<h5>Overview:</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 '<tt>fdiv</tt>' instruction returns the quotient of its two
2484operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2485
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2486<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2487
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2488<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2489<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2490of floating point values. Both arguments must have identical types.</p>
2491
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2492<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2493
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2494<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2495
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2496<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2497
2498<pre>
2499 &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]2500</pre>
2501</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2502
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2503<!-- _______________________________________________________________________ -->
2504<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2505</div>
2506<div class="doc_text">
2507<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2508<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]2509</pre>
2510<h5>Overview:</h5>
2511<p>The '<tt>urem</tt>' instruction returns the remainder from the
2512unsigned division of its two arguments.</p>
2513<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2514<p>The two arguments to the '<tt>urem</tt>' instruction must be
2515<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2516values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2517<h5>Semantics:</h5>
2518<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2519This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2520<p>Note that unsigned integer remainder and signed integer remainder are
2521distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2522<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2523<h5>Example:</h5>
2524<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2525</pre>
2526
2527</div>
2528<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2529<div class="doc_subsubsection">
2530 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2531</div>
2532
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2533<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2534
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2535<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2536
2537<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2538 &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]2539</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2540
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2541<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2542
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2543<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman3e3fd8c2007-11-05 23:35:22 +0000[diff] [blame]2544signed division of its two operands. This instruction can also take
2545<a href="#t_vector">vector</a> versions of the values in which case
2546the elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]2547
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2548<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2549
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2550<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2551<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2552values. Both arguments must have identical types.</p>
2553
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2554<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2555
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2556<p>This instruction returns the <i>remainder</i> of a division (where the result
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2557has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
2558operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2559a value. For more information about the difference, see <a
2560 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2561Math Forum</a>. For a table of how this is implemented in various languages,
2562please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
2563Wikipedia: modulo operation</a>.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2564<p>Note that signed integer remainder and unsigned integer remainder are
2565distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2566<p>Taking the remainder of a division by zero leads to undefined behavior.
2567Overflow also leads to undefined behavior; this is a rare case, but can occur,
2568for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2569(The remainder doesn't actually overflow, but this rule lets srem be
2570implemented using instructions that return both the result of the division
2571and the remainder.)</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2572<h5>Example:</h5>
2573<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2574</pre>
2575
2576</div>
2577<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2578<div class="doc_subsubsection">
2579 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2580
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2581<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2582
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2583<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2584<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]2585</pre>
2586<h5>Overview:</h5>
2587<p>The '<tt>frem</tt>' instruction returns the remainder from the
2588division of its two operands.</p>
2589<h5>Arguments:</h5>
2590<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2591<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2592of floating point values. Both arguments must have identical types.</p>
2593
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2594<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2595
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2596<p>This instruction returns the <i>remainder</i> of a division.
2597The remainder has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2598
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2599<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2600
2601<pre>
2602 &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]2603</pre>
2604</div>
2605
2606<!-- ======================================================================= -->
2607<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2608Operations</a> </div>
2609<div class="doc_text">
2610<p>Bitwise binary operators are used to do various forms of
2611bit-twiddling in a program. They are generally very efficient
2612instructions and can commonly be strength reduced from other
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2613instructions. They require two operands of the same type, execute an operation on them,
2614and 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]2615</div>
2616
2617<!-- _______________________________________________________________________ -->
2618<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2619Instruction</a> </div>
2620<div class="doc_text">
2621<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2622<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]2623</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2624
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2625<h5>Overview:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2626
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2627<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2628the left a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2629
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2630<h5>Arguments:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2631
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2632<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2633 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2634type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2635
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2636<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2637
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2638<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
2639where 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]2640equal to or larger than the number of bits in <tt>op1</tt>, the result is undefined.
2641If the arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2642corresponding shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2643
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2644<h5>Example:</h5><pre>
2645 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2646 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2647 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2648 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2649 &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]2650</pre>
2651</div>
2652<!-- _______________________________________________________________________ -->
2653<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2654Instruction</a> </div>
2655<div class="doc_text">
2656<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2657<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]2658</pre>
2659
2660<h5>Overview:</h5>
2661<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2662operand shifted to the right a specified number of bits with zero fill.</p>
2663
2664<h5>Arguments:</h5>
2665<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2666<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]2667type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2668
2669<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2670
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2671<p>This instruction always performs a logical shift right operation. The most
2672significant bits of the result will be filled with zero bits after the
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2673shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2674the number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
2675vectors, each vector element of <tt>op1</tt> is shifted by the corresponding shift
2676amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2677
2678<h5>Example:</h5>
2679<pre>
2680 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2681 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2682 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2683 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2684 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2685 &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]2686</pre>
2687</div>
2688
2689<!-- _______________________________________________________________________ -->
2690<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2691Instruction</a> </div>
2692<div class="doc_text">
2693
2694<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2695<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]2696</pre>
2697
2698<h5>Overview:</h5>
2699<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2700operand shifted to the right a specified number of bits with sign extension.</p>
2701
2702<h5>Arguments:</h5>
2703<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2704<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]2705type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2706
2707<h5>Semantics:</h5>
2708<p>This instruction always performs an arithmetic shift right operation,
2709The most significant bits of the result will be filled with the sign bit
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2710of <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]2711larger than the number of bits in <tt>op1</tt>, the result is undefined. If the
2712arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2713corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2714
2715<h5>Example:</h5>
2716<pre>
2717 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2718 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2719 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2720 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2721 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2722 &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]2723</pre>
2724</div>
2725
2726<!-- _______________________________________________________________________ -->
2727<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2728Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2729
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2730<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2731
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2732<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2733
2734<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2735 &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]2736</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2737
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2738<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2739
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2740<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2741its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2742
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2743<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2744
2745<p>The two arguments to the '<tt>and</tt>' instruction must be
2746<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2747values. Both arguments must have identical types.</p>
2748
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2749<h5>Semantics:</h5>
2750<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
2751<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2752<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2753<table border="1" cellspacing="0" cellpadding="4">
2754 <tbody>
2755 <tr>
2756 <td>In0</td>
2757 <td>In1</td>
2758 <td>Out</td>
2759 </tr>
2760 <tr>
2761 <td>0</td>
2762 <td>0</td>
2763 <td>0</td>
2764 </tr>
2765 <tr>
2766 <td>0</td>
2767 <td>1</td>
2768 <td>0</td>
2769 </tr>
2770 <tr>
2771 <td>1</td>
2772 <td>0</td>
2773 <td>0</td>
2774 </tr>
2775 <tr>
2776 <td>1</td>
2777 <td>1</td>
2778 <td>1</td>
2779 </tr>
2780 </tbody>
2781</table>
2782</div>
2783<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2784<pre>
2785 &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]2786 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2787 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
2788</pre>
2789</div>
2790<!-- _______________________________________________________________________ -->
2791<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
2792<div class="doc_text">
2793<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2794<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]2795</pre>
2796<h5>Overview:</h5>
2797<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2798or of its two operands.</p>
2799<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2800
2801<p>The two arguments to the '<tt>or</tt>' instruction must be
2802<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2803values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2804<h5>Semantics:</h5>
2805<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
2806<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2807<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2808<table border="1" cellspacing="0" cellpadding="4">
2809 <tbody>
2810 <tr>
2811 <td>In0</td>
2812 <td>In1</td>
2813 <td>Out</td>
2814 </tr>
2815 <tr>
2816 <td>0</td>
2817 <td>0</td>
2818 <td>0</td>
2819 </tr>
2820 <tr>
2821 <td>0</td>
2822 <td>1</td>
2823 <td>1</td>
2824 </tr>
2825 <tr>
2826 <td>1</td>
2827 <td>0</td>
2828 <td>1</td>
2829 </tr>
2830 <tr>
2831 <td>1</td>
2832 <td>1</td>
2833 <td>1</td>
2834 </tr>
2835 </tbody>
2836</table>
2837</div>
2838<h5>Example:</h5>
2839<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2840 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2841 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
2842</pre>
2843</div>
2844<!-- _______________________________________________________________________ -->
2845<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2846Instruction</a> </div>
2847<div class="doc_text">
2848<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2849<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]2850</pre>
2851<h5>Overview:</h5>
2852<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2853or of its two operands. The <tt>xor</tt> is used to implement the
2854"one's complement" operation, which is the "~" operator in C.</p>
2855<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2856<p>The two arguments to the '<tt>xor</tt>' instruction must be
2857<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2858values. Both arguments must have identical types.</p>
2859
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2860<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2861
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2862<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
2863<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2864<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2865<table border="1" cellspacing="0" cellpadding="4">
2866 <tbody>
2867 <tr>
2868 <td>In0</td>
2869 <td>In1</td>
2870 <td>Out</td>
2871 </tr>
2872 <tr>
2873 <td>0</td>
2874 <td>0</td>
2875 <td>0</td>
2876 </tr>
2877 <tr>
2878 <td>0</td>
2879 <td>1</td>
2880 <td>1</td>
2881 </tr>
2882 <tr>
2883 <td>1</td>
2884 <td>0</td>
2885 <td>1</td>
2886 </tr>
2887 <tr>
2888 <td>1</td>
2889 <td>1</td>
2890 <td>0</td>
2891 </tr>
2892 </tbody>
2893</table>
2894</div>
2895<p> </p>
2896<h5>Example:</h5>
2897<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2898 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2899 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2900 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
2901</pre>
2902</div>
2903
2904<!-- ======================================================================= -->
2905<div class="doc_subsection">
2906 <a name="vectorops">Vector Operations</a>
2907</div>
2908
2909<div class="doc_text">
2910
2911<p>LLVM supports several instructions to represent vector operations in a
2912target-independent manner. These instructions cover the element-access and
2913vector-specific operations needed to process vectors effectively. While LLVM
2914does directly support these vector operations, many sophisticated algorithms
2915will want to use target-specific intrinsics to take full advantage of a specific
2916target.</p>
2917
2918</div>
2919
2920<!-- _______________________________________________________________________ -->
2921<div class="doc_subsubsection">
2922 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2923</div>
2924
2925<div class="doc_text">
2926
2927<h5>Syntax:</h5>
2928
2929<pre>
2930 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
2931</pre>
2932
2933<h5>Overview:</h5>
2934
2935<p>
2936The '<tt>extractelement</tt>' instruction extracts a single scalar
2937element from a vector at a specified index.
2938</p>
2939
2940
2941<h5>Arguments:</h5>
2942
2943<p>
2944The first operand of an '<tt>extractelement</tt>' instruction is a
2945value of <a href="#t_vector">vector</a> type. The second operand is
2946an index indicating the position from which to extract the element.
2947The index may be a variable.</p>
2948
2949<h5>Semantics:</h5>
2950
2951<p>
2952The result is a scalar of the same type as the element type of
2953<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2954<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2955results are undefined.
2956</p>
2957
2958<h5>Example:</h5>
2959
2960<pre>
2961 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
2962</pre>
2963</div>
2964
2965
2966<!-- _______________________________________________________________________ -->
2967<div class="doc_subsubsection">
2968 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2969</div>
2970
2971<div class="doc_text">
2972
2973<h5>Syntax:</h5>
2974
2975<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]2976 &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]2977</pre>
2978
2979<h5>Overview:</h5>
2980
2981<p>
2982The '<tt>insertelement</tt>' instruction inserts a scalar
2983element into a vector at a specified index.
2984</p>
2985
2986
2987<h5>Arguments:</h5>
2988
2989<p>
2990The first operand of an '<tt>insertelement</tt>' instruction is a
2991value of <a href="#t_vector">vector</a> type. The second operand is a
2992scalar value whose type must equal the element type of the first
2993operand. The third operand is an index indicating the position at
2994which to insert the value. The index may be a variable.</p>
2995
2996<h5>Semantics:</h5>
2997
2998<p>
2999The result is a vector of the same type as <tt>val</tt>. Its
3000element values are those of <tt>val</tt> except at position
3001<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
3002exceeds the length of <tt>val</tt>, the results are undefined.
3003</p>
3004
3005<h5>Example:</h5>
3006
3007<pre>
3008 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
3009</pre>
3010</div>
3011
3012<!-- _______________________________________________________________________ -->
3013<div class="doc_subsubsection">
3014 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3015</div>
3016
3017<div class="doc_text">
3018
3019<h5>Syntax:</h5>
3020
3021<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3022 &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]3023</pre>
3024
3025<h5>Overview:</h5>
3026
3027<p>
3028The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3029from two input vectors, returning a vector with the same element type as
3030the input and length that is the same as the shuffle mask.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3031</p>
3032
3033<h5>Arguments:</h5>
3034
3035<p>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3036The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3037with types that match each other. The third argument is a shuffle mask whose
3038element type is always 'i32'. The result of the instruction is a vector whose
3039length is the same as the shuffle mask and whose element type is the same as
3040the element type of the first two operands.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3041</p>
3042
3043<p>
3044The shuffle mask operand is required to be a constant vector with either
3045constant integer or undef values.
3046</p>
3047
3048<h5>Semantics:</h5>
3049
3050<p>
3051The elements of the two input vectors are numbered from left to right across
3052both of the vectors. The shuffle mask operand specifies, for each element of
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3053the result vector, which element of the two input vectors the result element
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3054gets. The element selector may be undef (meaning "don't care") and the second
3055operand may be undef if performing a shuffle from only one vector.
3056</p>
3057
3058<h5>Example:</h5>
3059
3060<pre>
3061 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3062 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3063 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3064 &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]3065 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3066 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3067 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3068 &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]3069</pre>
3070</div>
3071
3072
3073<!-- ======================================================================= -->
3074<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3075 <a name="aggregateops">Aggregate Operations</a>
3076</div>
3077
3078<div class="doc_text">
3079
3080<p>LLVM supports several instructions for working with aggregate values.
3081</p>
3082
3083</div>
3084
3085<!-- _______________________________________________________________________ -->
3086<div class="doc_subsubsection">
3087 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3088</div>
3089
3090<div class="doc_text">
3091
3092<h5>Syntax:</h5>
3093
3094<pre>
3095 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3096</pre>
3097
3098<h5>Overview:</h5>
3099
3100<p>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3101The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3102or array element from an aggregate value.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3103</p>
3104
3105
3106<h5>Arguments:</h5>
3107
3108<p>
3109The first operand of an '<tt>extractvalue</tt>' instruction is a
3110value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3111type. The operands are constant indices to specify which value to extract
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3112in a similar manner as indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3113'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3114</p>
3115
3116<h5>Semantics:</h5>
3117
3118<p>
3119The result is the value at the position in the aggregate specified by
3120the index operands.
3121</p>
3122
3123<h5>Example:</h5>
3124
3125<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3126 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3127</pre>
3128</div>
3129
3130
3131<!-- _______________________________________________________________________ -->
3132<div class="doc_subsubsection">
3133 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3134</div>
3135
3136<div class="doc_text">
3137
3138<h5>Syntax:</h5>
3139
3140<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3141 &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]3142</pre>
3143
3144<h5>Overview:</h5>
3145
3146<p>
3147The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3148into a struct field or array element in an aggregate.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3149</p>
3150
3151
3152<h5>Arguments:</h5>
3153
3154<p>
3155The first operand of an '<tt>insertvalue</tt>' instruction is a
3156value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
3157The second operand is a first-class value to insert.
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]3158The following operands are constant indices
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3159indicating the position at which to insert the value in a similar manner as
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3160indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3161'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3162The value to insert must have the same type as the value identified
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3163by the indices.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3164</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3165
3166<h5>Semantics:</h5>
3167
3168<p>
3169The result is an aggregate of the same type as <tt>val</tt>. Its
3170value is that of <tt>val</tt> except that the value at the position
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3171specified by the indices is that of <tt>elt</tt>.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3172</p>
3173
3174<h5>Example:</h5>
3175
3176<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3177 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3178</pre>
3179</div>
3180
3181
3182<!-- ======================================================================= -->
3183<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3184 <a name="memoryops">Memory Access and Addressing Operations</a>
3185</div>
3186
3187<div class="doc_text">
3188
3189<p>A key design point of an SSA-based representation is how it
3190represents memory. In LLVM, no memory locations are in SSA form, which
3191makes things very simple. This section describes how to read, write,
3192allocate, and free memory in LLVM.</p>
3193
3194</div>
3195
3196<!-- _______________________________________________________________________ -->
3197<div class="doc_subsubsection">
3198 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3199</div>
3200
3201<div class="doc_text">
3202
3203<h5>Syntax:</h5>
3204
3205<pre>
3206 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3207</pre>
3208
3209<h5>Overview:</h5>
3210
3211<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3212heap and returns a pointer to it. The object is always allocated in the generic
3213address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3214
3215<h5>Arguments:</h5>
3216
3217<p>The '<tt>malloc</tt>' instruction allocates
3218<tt>sizeof(&lt;type&gt;)*NumElements</tt>
3219bytes of memory from the operating system and returns a pointer of the
3220appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3221number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3222If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3223be aligned to at least that boundary. If not specified, or if zero, the target can
3224choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3225
3226<p>'<tt>type</tt>' must be a sized type.</p>
3227
3228<h5>Semantics:</h5>
3229
3230<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]3231a pointer is returned. The result of a zero byte allocation is undefined. The
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3232result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3233
3234<h5>Example:</h5>
3235
3236<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3237 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3238
3239 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3240 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3241 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3242 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3243 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3244</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3245
3246<p>Note that the code generator does not yet respect the
3247 alignment value.</p>
3248
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3249</div>
3250
3251<!-- _______________________________________________________________________ -->
3252<div class="doc_subsubsection">
3253 <a name="i_free">'<tt>free</tt>' Instruction</a>
3254</div>
3255
3256<div class="doc_text">
3257
3258<h5>Syntax:</h5>
3259
3260<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3261 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3262</pre>
3263
3264<h5>Overview:</h5>
3265
3266<p>The '<tt>free</tt>' instruction returns memory back to the unused
3267memory heap to be reallocated in the future.</p>
3268
3269<h5>Arguments:</h5>
3270
3271<p>'<tt>value</tt>' shall be a pointer value that points to a value
3272that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3273instruction.</p>
3274
3275<h5>Semantics:</h5>
3276
3277<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner329d6532008-04-19 22:41:32 +0000[diff] [blame]3278after this instruction executes. If the pointer is null, the operation
3279is a noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3280
3281<h5>Example:</h5>
3282
3283<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3284 %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]3285 free [4 x i8]* %array
3286</pre>
3287</div>
3288
3289<!-- _______________________________________________________________________ -->
3290<div class="doc_subsubsection">
3291 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3292</div>
3293
3294<div class="doc_text">
3295
3296<h5>Syntax:</h5>
3297
3298<pre>
3299 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3300</pre>
3301
3302<h5>Overview:</h5>
3303
3304<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3305currently executing function, to be automatically released when this function
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3306returns to its caller. The object is always allocated in the generic address
3307space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3308
3309<h5>Arguments:</h5>
3310
3311<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
3312bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3313appropriate type to the program. If "NumElements" is specified, it is the
3314number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3315If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3316to be aligned to at least that boundary. If not specified, or if zero, the target
3317can choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3318
3319<p>'<tt>type</tt>' may be any sized type.</p>
3320
3321<h5>Semantics:</h5>
3322
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3323<p>Memory is allocated; a pointer is returned. The operation is undefiend if
3324there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3325memory is automatically released when the function returns. The '<tt>alloca</tt>'
3326instruction is commonly used to represent automatic variables that must
3327have an address available. When the function returns (either with the <tt><a
3328 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]3329instructions), the memory is reclaimed. Allocating zero bytes
3330is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3331
3332<h5>Example:</h5>
3333
3334<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3335 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3336 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3337 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3338 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3339</pre>
3340</div>
3341
3342<!-- _______________________________________________________________________ -->
3343<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3344Instruction</a> </div>
3345<div class="doc_text">
3346<h5>Syntax:</h5>
3347<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>
3348<h5>Overview:</h5>
3349<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
3350<h5>Arguments:</h5>
3351<p>The argument to the '<tt>load</tt>' instruction specifies the memory
3352address from which to load. The pointer must point to a <a
3353 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3354marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
3355the number or order of execution of this <tt>load</tt> with other
3356volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3357instructions. </p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3358<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3359The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3360(that is, the alignment of the memory address). A value of 0 or an
3361omitted "align" argument means that the operation has the preferential
3362alignment for the target. It is the responsibility of the code emitter
3363to ensure that the alignment information is correct. Overestimating
3364the alignment results in an undefined behavior. Underestimating the
3365alignment may produce less efficient code. An alignment of 1 is always
3366safe.
3367</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3368<h5>Semantics:</h5>
3369<p>The location of memory pointed to is loaded.</p>
3370<h5>Examples:</h5>
3371<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3372 <a
3373 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3374 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3375</pre>
3376</div>
3377<!-- _______________________________________________________________________ -->
3378<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3379Instruction</a> </div>
3380<div class="doc_text">
3381<h5>Syntax:</h5>
3382<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3383 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3384</pre>
3385<h5>Overview:</h5>
3386<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
3387<h5>Arguments:</h5>
3388<p>There are two arguments to the '<tt>store</tt>' instruction: a value
3389to 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]3390operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3391of the '<tt>&lt;value&gt;</tt>'
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3392operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
3393optimizer is not allowed to modify the number or order of execution of
3394this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3395 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3396<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3397The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3398(that is, the alignment of the memory address). A value of 0 or an
3399omitted "align" argument means that the operation has the preferential
3400alignment for the target. It is the responsibility of the code emitter
3401to ensure that the alignment information is correct. Overestimating
3402the alignment results in an undefined behavior. Underestimating the
3403alignment may produce less efficient code. An alignment of 1 is always
3404safe.
3405</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3406<h5>Semantics:</h5>
3407<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
3408at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
3409<h5>Example:</h5>
3410<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3411 store i32 3, i32* %ptr <i>; yields {void}</i>
3412 %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]3413</pre>
3414</div>
3415
3416<!-- _______________________________________________________________________ -->
3417<div class="doc_subsubsection">
3418 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3419</div>
3420
3421<div class="doc_text">
3422<h5>Syntax:</h5>
3423<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3424 &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]3425</pre>
3426
3427<h5>Overview:</h5>
3428
3429<p>
3430The '<tt>getelementptr</tt>' instruction is used to get the address of a
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3431subelement of an aggregate data structure. It performs address calculation only
3432and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3433
3434<h5>Arguments:</h5>
3435
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3436<p>The first argument is always a pointer, and forms the basis of the
3437calculation. The remaining arguments are indices, that indicate which of the
3438elements of the aggregate object are indexed. The interpretation of each index
3439is dependent on the type being indexed into. The first index always indexes the
3440pointer value given as the first argument, the second index indexes a value of
3441the type pointed to (not necessarily the value directly pointed to, since the
3442first index can be non-zero), etc. The first type indexed into must be a pointer
3443value, subsequent types can be arrays, vectors and structs. Note that subsequent
3444types being indexed into can never be pointers, since that would require loading
3445the pointer before continuing calculation.</p>
3446
3447<p>The type of each index argument depends on the type it is indexing into.
3448When indexing into a (packed) structure, only <tt>i32</tt> integer
3449<b>constants</b> are allowed. When indexing into an array, pointer or vector,
3450only integers of 32 or 64 bits are allowed (also non-constants). 32-bit values
3451will be sign extended to 64-bits if required.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3452
3453<p>For example, let's consider a C code fragment and how it gets
3454compiled to LLVM:</p>
3455
3456<div class="doc_code">
3457<pre>
3458struct RT {
3459 char A;
3460 int B[10][20];
3461 char C;
3462};
3463struct ST {
3464 int X;
3465 double Y;
3466 struct RT Z;
3467};
3468
3469int *foo(struct ST *s) {
3470 return &amp;s[1].Z.B[5][13];
3471}
3472</pre>
3473</div>
3474
3475<p>The LLVM code generated by the GCC frontend is:</p>
3476
3477<div class="doc_code">
3478<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]3479%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
3480%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3481
3482define i32* %foo(%ST* %s) {
3483entry:
3484 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3485 ret i32* %reg
3486}
3487</pre>
3488</div>
3489
3490<h5>Semantics:</h5>
3491
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3492<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
3493type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3494}</tt>' type, a structure. The second index indexes into the third element of
3495the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3496i8 }</tt>' type, another structure. The third index indexes into the second
3497element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3498array. The two dimensions of the array are subscripted into, yielding an
3499'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3500to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
3501
3502<p>Note that it is perfectly legal to index partially through a
3503structure, returning a pointer to an inner element. Because of this,
3504the LLVM code for the given testcase is equivalent to:</p>
3505
3506<pre>
3507 define i32* %foo(%ST* %s) {
3508 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3509 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3510 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3511 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3512 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3513 ret i32* %t5
3514 }
3515</pre>
3516
3517<p>Note that it is undefined to access an array out of bounds: array and
3518pointer indexes must always be within the defined bounds of the array type.
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]3519The one exception for this rule is zero length arrays. These arrays are
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3520defined to be accessible as variable length arrays, which requires access
3521beyond the zero'th element.</p>
3522
3523<p>The getelementptr instruction is often confusing. For some more insight
3524into how it works, see <a href="GetElementPtr.html">the getelementptr
3525FAQ</a>.</p>
3526
3527<h5>Example:</h5>
3528
3529<pre>
3530 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3531 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3532 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3533 %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]3534 <i>; yields i8*:eptr</i>
3535 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3536</pre>
3537</div>
3538
3539<!-- ======================================================================= -->
3540<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3541</div>
3542<div class="doc_text">
3543<p>The instructions in this category are the conversion instructions (casting)
3544which all take a single operand and a type. They perform various bit conversions
3545on the operand.</p>
3546</div>
3547
3548<!-- _______________________________________________________________________ -->
3549<div class="doc_subsubsection">
3550 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3551</div>
3552<div class="doc_text">
3553
3554<h5>Syntax:</h5>
3555<pre>
3556 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3557</pre>
3558
3559<h5>Overview:</h5>
3560<p>
3561The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3562</p>
3563
3564<h5>Arguments:</h5>
3565<p>
3566The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3567be an <a href="#t_integer">integer</a> type, and a type that specifies the size
3568and type of the result, which must be an <a href="#t_integer">integer</a>
3569type. The bit size of <tt>value</tt> must be larger than the bit size of
3570<tt>ty2</tt>. Equal sized types are not allowed.</p>
3571
3572<h5>Semantics:</h5>
3573<p>
3574The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
3575and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3576larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3577It will always truncate bits.</p>
3578
3579<h5>Example:</h5>
3580<pre>
3581 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3582 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3583 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
3584</pre>
3585</div>
3586
3587<!-- _______________________________________________________________________ -->
3588<div class="doc_subsubsection">
3589 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3590</div>
3591<div class="doc_text">
3592
3593<h5>Syntax:</h5>
3594<pre>
3595 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3596</pre>
3597
3598<h5>Overview:</h5>
3599<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3600<tt>ty2</tt>.</p>
3601
3602
3603<h5>Arguments:</h5>
3604<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
3605<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3606also be of <a href="#t_integer">integer</a> type. The bit size of the
3607<tt>value</tt> must be smaller than the bit size of the destination type,
3608<tt>ty2</tt>.</p>
3609
3610<h5>Semantics:</h5>
3611<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
3612bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
3613
3614<p>When zero extending from i1, the result will always be either 0 or 1.</p>
3615
3616<h5>Example:</h5>
3617<pre>
3618 %X = zext i32 257 to i64 <i>; yields i64:257</i>
3619 %Y = zext i1 true to i32 <i>; yields i32:1</i>
3620</pre>
3621</div>
3622
3623<!-- _______________________________________________________________________ -->
3624<div class="doc_subsubsection">
3625 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3626</div>
3627<div class="doc_text">
3628
3629<h5>Syntax:</h5>
3630<pre>
3631 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3632</pre>
3633
3634<h5>Overview:</h5>
3635<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3636
3637<h5>Arguments:</h5>
3638<p>
3639The '<tt>sext</tt>' instruction takes a value to cast, which must be of
3640<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3641also be of <a href="#t_integer">integer</a> type. The bit size of the
3642<tt>value</tt> must be smaller than the bit size of the destination type,
3643<tt>ty2</tt>.</p>
3644
3645<h5>Semantics:</h5>
3646<p>
3647The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3648bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
3649the type <tt>ty2</tt>.</p>
3650
3651<p>When sign extending from i1, the extension always results in -1 or 0.</p>
3652
3653<h5>Example:</h5>
3654<pre>
3655 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
3656 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
3657</pre>
3658</div>
3659
3660<!-- _______________________________________________________________________ -->
3661<div class="doc_subsubsection">
3662 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3663</div>
3664
3665<div class="doc_text">
3666
3667<h5>Syntax:</h5>
3668
3669<pre>
3670 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3671</pre>
3672
3673<h5>Overview:</h5>
3674<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3675<tt>ty2</tt>.</p>
3676
3677
3678<h5>Arguments:</h5>
3679<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3680 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3681cast it to. The size of <tt>value</tt> must be larger than the size of
3682<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3683<i>no-op cast</i>.</p>
3684
3685<h5>Semantics:</h5>
3686<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3687<a href="#t_floating">floating point</a> type to a smaller
3688<a href="#t_floating">floating point</a> type. If the value cannot fit within
3689the destination type, <tt>ty2</tt>, then the results are undefined.</p>
3690
3691<h5>Example:</h5>
3692<pre>
3693 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3694 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3695</pre>
3696</div>
3697
3698<!-- _______________________________________________________________________ -->
3699<div class="doc_subsubsection">
3700 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3701</div>
3702<div class="doc_text">
3703
3704<h5>Syntax:</h5>
3705<pre>
3706 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3707</pre>
3708
3709<h5>Overview:</h5>
3710<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3711floating point value.</p>
3712
3713<h5>Arguments:</h5>
3714<p>The '<tt>fpext</tt>' instruction takes a
3715<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
3716and a <a href="#t_floating">floating point</a> type to cast it to. The source
3717type must be smaller than the destination type.</p>
3718
3719<h5>Semantics:</h5>
3720<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
3721<a href="#t_floating">floating point</a> type to a larger
3722<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
3723used to make a <i>no-op cast</i> because it always changes bits. Use
3724<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
3725
3726<h5>Example:</h5>
3727<pre>
3728 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3729 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3730</pre>
3731</div>
3732
3733<!-- _______________________________________________________________________ -->
3734<div class="doc_subsubsection">
3735 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
3736</div>
3737<div class="doc_text">
3738
3739<h5>Syntax:</h5>
3740<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3741 &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]3742</pre>
3743
3744<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3745<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3746unsigned integer equivalent of type <tt>ty2</tt>.
3747</p>
3748
3749<h5>Arguments:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3750<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]3751scalar or vector <a href="#t_floating">floating point</a> value, and a type
3752to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3753type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3754vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3755
3756<h5>Semantics:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3757<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3758<a href="#t_floating">floating point</a> operand into the nearest (rounding
3759towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3760the results are undefined.</p>
3761
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3762<h5>Example:</h5>
3763<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3764 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3765 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3766 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3767</pre>
3768</div>
3769
3770<!-- _______________________________________________________________________ -->
3771<div class="doc_subsubsection">
3772 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
3773</div>
3774<div class="doc_text">
3775
3776<h5>Syntax:</h5>
3777<pre>
3778 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3779</pre>
3780
3781<h5>Overview:</h5>
3782<p>The '<tt>fptosi</tt>' instruction converts
3783<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
3784</p>
3785
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3786<h5>Arguments:</h5>
3787<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]3788scalar or vector <a href="#t_floating">floating point</a> value, and a type
3789to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3790type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3791vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3792
3793<h5>Semantics:</h5>
3794<p>The '<tt>fptosi</tt>' instruction converts its
3795<a href="#t_floating">floating point</a> operand into the nearest (rounding
3796towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3797the results are undefined.</p>
3798
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3799<h5>Example:</h5>
3800<pre>
3801 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3802 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3803 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
3804</pre>
3805</div>
3806
3807<!-- _______________________________________________________________________ -->
3808<div class="doc_subsubsection">
3809 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
3810</div>
3811<div class="doc_text">
3812
3813<h5>Syntax:</h5>
3814<pre>
3815 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3816</pre>
3817
3818<h5>Overview:</h5>
3819<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
3820integer and converts that value to the <tt>ty2</tt> type.</p>
3821
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3822<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3823<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3824scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3825to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3826type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3827floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3828
3829<h5>Semantics:</h5>
3830<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
3831integer quantity and converts it to the corresponding floating point value. If
3832the value cannot fit in the floating point value, the results are undefined.</p>
3833
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3834<h5>Example:</h5>
3835<pre>
3836 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3837 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3838</pre>
3839</div>
3840
3841<!-- _______________________________________________________________________ -->
3842<div class="doc_subsubsection">
3843 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
3844</div>
3845<div class="doc_text">
3846
3847<h5>Syntax:</h5>
3848<pre>
3849 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3850</pre>
3851
3852<h5>Overview:</h5>
3853<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
3854integer and converts that value to the <tt>ty2</tt> type.</p>
3855
3856<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3857<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3858scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3859to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3860type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3861floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3862
3863<h5>Semantics:</h5>
3864<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
3865integer quantity and converts it to the corresponding floating point value. If
3866the value cannot fit in the floating point value, the results are undefined.</p>
3867
3868<h5>Example:</h5>
3869<pre>
3870 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3871 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3872</pre>
3873</div>
3874
3875<!-- _______________________________________________________________________ -->
3876<div class="doc_subsubsection">
3877 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3878</div>
3879<div class="doc_text">
3880
3881<h5>Syntax:</h5>
3882<pre>
3883 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3884</pre>
3885
3886<h5>Overview:</h5>
3887<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3888the integer type <tt>ty2</tt>.</p>
3889
3890<h5>Arguments:</h5>
3891<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3892must 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]3893<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]3894
3895<h5>Semantics:</h5>
3896<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3897<tt>ty2</tt> by interpreting the pointer value as an integer and either
3898truncating or zero extending that value to the size of the integer type. If
3899<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3900<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3901are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3902change.</p>
3903
3904<h5>Example:</h5>
3905<pre>
3906 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3907 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
3908</pre>
3909</div>
3910
3911<!-- _______________________________________________________________________ -->
3912<div class="doc_subsubsection">
3913 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3914</div>
3915<div class="doc_text">
3916
3917<h5>Syntax:</h5>
3918<pre>
3919 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3920</pre>
3921
3922<h5>Overview:</h5>
3923<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3924a pointer type, <tt>ty2</tt>.</p>
3925
3926<h5>Arguments:</h5>
3927<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
3928value to cast, and a type to cast it to, which must be a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3929<a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3930
3931<h5>Semantics:</h5>
3932<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3933<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3934the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3935size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3936the size of a pointer then a zero extension is done. If they are the same size,
3937nothing is done (<i>no-op cast</i>).</p>
3938
3939<h5>Example:</h5>
3940<pre>
3941 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3942 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3943 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
3944</pre>
3945</div>
3946
3947<!-- _______________________________________________________________________ -->
3948<div class="doc_subsubsection">
3949 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
3950</div>
3951<div class="doc_text">
3952
3953<h5>Syntax:</h5>
3954<pre>
3955 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3956</pre>
3957
3958<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3959
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3960<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
3961<tt>ty2</tt> without changing any bits.</p>
3962
3963<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3964
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3965<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Dan Gohman7305fa02008-09-08 16:45:59 +0000[diff] [blame]3966a non-aggregate first class value, and a type to cast it to, which must also be
3967a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
3968<tt>value</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3969and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3970type is a pointer, the destination type must also be a pointer. This
3971instruction supports bitwise conversion of vectors to integers and to vectors
3972of other types (as long as they have the same size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3973
3974<h5>Semantics:</h5>
3975<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
3976<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3977this conversion. The conversion is done as if the <tt>value</tt> had been
3978stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3979converted to other pointer types with this instruction. To convert pointers to
3980other types, use the <a href="#i_inttoptr">inttoptr</a> or
3981<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
3982
3983<h5>Example:</h5>
3984<pre>
3985 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
3986 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3987 %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]3988</pre>
3989</div>
3990
3991<!-- ======================================================================= -->
3992<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3993<div class="doc_text">
3994<p>The instructions in this category are the "miscellaneous"
3995instructions, which defy better classification.</p>
3996</div>
3997
3998<!-- _______________________________________________________________________ -->
3999<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4000</div>
4001<div class="doc_text">
4002<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4003<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]4004</pre>
4005<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4006<p>The '<tt>icmp</tt>' instruction returns a boolean value or
4007a vector of boolean values based on comparison
4008of its two integer, integer vector, or pointer operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4009<h5>Arguments:</h5>
4010<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
4011the condition code indicating the kind of comparison to perform. It is not
4012a value, just a keyword. The possible condition code are:
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4013</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4014<ol>
4015 <li><tt>eq</tt>: equal</li>
4016 <li><tt>ne</tt>: not equal </li>
4017 <li><tt>ugt</tt>: unsigned greater than</li>
4018 <li><tt>uge</tt>: unsigned greater or equal</li>
4019 <li><tt>ult</tt>: unsigned less than</li>
4020 <li><tt>ule</tt>: unsigned less or equal</li>
4021 <li><tt>sgt</tt>: signed greater than</li>
4022 <li><tt>sge</tt>: signed greater or equal</li>
4023 <li><tt>slt</tt>: signed less than</li>
4024 <li><tt>sle</tt>: signed less or equal</li>
4025</ol>
4026<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4027<a href="#t_pointer">pointer</a>
4028or integer <a href="#t_vector">vector</a> typed.
4029They must also be identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4030<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4031<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]4032the condition code given as <tt>cond</tt>. The comparison performed always
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4033yields 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]4034</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4035<ol>
4036 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
4037 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
4038 </li>
4039 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4040 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4041 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4042 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4043 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4044 <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]4045 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4046 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4047 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4048 <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]4049 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4050 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4051 <li><tt>sge</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4052 <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]4053 <li><tt>slt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4054 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4055 <li><tt>sle</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4056 <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]4057</ol>
4058<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
4059values are compared as if they were integers.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4060<p>If the operands are integer vectors, then they are compared
4061element by element. The result is an <tt>i1</tt> vector with
4062the same number of elements as the values being compared.
4063Otherwise, the result is an <tt>i1</tt>.
4064</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4065
4066<h5>Example:</h5>
4067<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
4068 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4069 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4070 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4071 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4072 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4073</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame^]4074
4075<p>Note that the code generator does not yet support vector types with
4076 the <tt>icmp</tt> instruction.</p>
4077
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4078</div>
4079
4080<!-- _______________________________________________________________________ -->
4081<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4082</div>
4083<div class="doc_text">
4084<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4085<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]4086</pre>
4087<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4088<p>The '<tt>fcmp</tt>' instruction returns a boolean value
4089or vector of boolean values based on comparison
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4090of its operands.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4091<p>
4092If the operands are floating point scalars, then the result
4093type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
4094</p>
4095<p>If the operands are floating point vectors, then the result type
4096is a vector of boolean with the same number of elements as the
4097operands being compared.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4098<h5>Arguments:</h5>
4099<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
4100the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4101a value, just a keyword. The possible condition code are:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4102<ol>
4103 <li><tt>false</tt>: no comparison, always returns false</li>
4104 <li><tt>oeq</tt>: ordered and equal</li>
4105 <li><tt>ogt</tt>: ordered and greater than </li>
4106 <li><tt>oge</tt>: ordered and greater than or equal</li>
4107 <li><tt>olt</tt>: ordered and less than </li>
4108 <li><tt>ole</tt>: ordered and less than or equal</li>
4109 <li><tt>one</tt>: ordered and not equal</li>
4110 <li><tt>ord</tt>: ordered (no nans)</li>
4111 <li><tt>ueq</tt>: unordered or equal</li>
4112 <li><tt>ugt</tt>: unordered or greater than </li>
4113 <li><tt>uge</tt>: unordered or greater than or equal</li>
4114 <li><tt>ult</tt>: unordered or less than </li>
4115 <li><tt>ule</tt>: unordered or less than or equal</li>
4116 <li><tt>une</tt>: unordered or not equal</li>
4117 <li><tt>uno</tt>: unordered (either nans)</li>
4118 <li><tt>true</tt>: no comparison, always returns true</li>
4119</ol>
4120<p><i>Ordered</i> means that neither operand is a QNAN while
4121<i>unordered</i> means that either operand may be a QNAN.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4122<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
4123either a <a href="#t_floating">floating point</a> type
4124or a <a href="#t_vector">vector</a> of floating point type.
4125They must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4126<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4127<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4128according to the condition code given as <tt>cond</tt>.
4129If the operands are vectors, then the vectors are compared
4130element by element.
4131Each comparison performed
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4132always yields an <a href="#t_primitive">i1</a> result, as follows:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4133<ol>
4134 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
4135 <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]4136 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4137 <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]4138 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4139 <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]4140 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4141 <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]4142 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4143 <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]4144 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4145 <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]4146 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4147 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
4148 <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]4149 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4150 <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]4151 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4152 <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]4153 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4154 <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]4155 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4156 <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]4157 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4158 <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]4159 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4160 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
4161 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4162</ol>
4163
4164<h5>Example:</h5>
4165<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]4166 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4167 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4168 &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]4169</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame^]4170
4171<p>Note that the code generator does not yet support vector types with
4172 the <tt>fcmp</tt> instruction.</p>
4173
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4174</div>
4175
4176<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4177<div class="doc_subsubsection">
4178 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
4179</div>
4180<div class="doc_text">
4181<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4182<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]4183</pre>
4184<h5>Overview:</h5>
4185<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
4186element-wise comparison of its two integer vector operands.</p>
4187<h5>Arguments:</h5>
4188<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
4189the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4190a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4191<ol>
4192 <li><tt>eq</tt>: equal</li>
4193 <li><tt>ne</tt>: not equal </li>
4194 <li><tt>ugt</tt>: unsigned greater than</li>
4195 <li><tt>uge</tt>: unsigned greater or equal</li>
4196 <li><tt>ult</tt>: unsigned less than</li>
4197 <li><tt>ule</tt>: unsigned less or equal</li>
4198 <li><tt>sgt</tt>: signed greater than</li>
4199 <li><tt>sge</tt>: signed greater or equal</li>
4200 <li><tt>slt</tt>: signed less than</li>
4201 <li><tt>sle</tt>: signed less or equal</li>
4202</ol>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4203<p>The remaining two arguments must be <a href="#t_vector">vector</a> or
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4204<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
4205<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4206<p>The '<tt>vicmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4207according to the condition code given as <tt>cond</tt>. The comparison yields a
4208<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
4209identical type as the values being compared. The most significant bit in each
4210element is 1 if the element-wise comparison evaluates to true, and is 0
4211otherwise. All other bits of the result are undefined. The condition codes
4212are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4213instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4214
4215<h5>Example:</h5>
4216<pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4217 &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>
4218 &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]4219</pre>
4220</div>
4221
4222<!-- _______________________________________________________________________ -->
4223<div class="doc_subsubsection">
4224 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
4225</div>
4226<div class="doc_text">
4227<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4228<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]4229<h5>Overview:</h5>
4230<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
4231element-wise comparison of its two floating point vector operands. The output
4232elements have the same width as the input elements.</p>
4233<h5>Arguments:</h5>
4234<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
4235the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4236a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4237<ol>
4238 <li><tt>false</tt>: no comparison, always returns false</li>
4239 <li><tt>oeq</tt>: ordered and equal</li>
4240 <li><tt>ogt</tt>: ordered and greater than </li>
4241 <li><tt>oge</tt>: ordered and greater than or equal</li>
4242 <li><tt>olt</tt>: ordered and less than </li>
4243 <li><tt>ole</tt>: ordered and less than or equal</li>
4244 <li><tt>one</tt>: ordered and not equal</li>
4245 <li><tt>ord</tt>: ordered (no nans)</li>
4246 <li><tt>ueq</tt>: unordered or equal</li>
4247 <li><tt>ugt</tt>: unordered or greater than </li>
4248 <li><tt>uge</tt>: unordered or greater than or equal</li>
4249 <li><tt>ult</tt>: unordered or less than </li>
4250 <li><tt>ule</tt>: unordered or less than or equal</li>
4251 <li><tt>une</tt>: unordered or not equal</li>
4252 <li><tt>uno</tt>: unordered (either nans)</li>
4253 <li><tt>true</tt>: no comparison, always returns true</li>
4254</ol>
4255<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4256<a href="#t_floating">floating point</a> typed. They must also be identical
4257types.</p>
4258<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4259<p>The '<tt>vfcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4260according to the condition code given as <tt>cond</tt>. The comparison yields a
4261<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4262an identical number of elements as the values being compared, and each element
4263having identical with to the width of the floating point elements. The most
4264significant bit in each element is 1 if the element-wise comparison evaluates to
4265true, and is 0 otherwise. All other bits of the result are undefined. The
4266condition codes are evaluated identically to the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4267<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4268
4269<h5>Example:</h5>
4270<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]4271 <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4272 &lt;result&gt; = vfcmp oeq &lt;2 x float&gt; &lt; float 4, float 0 &gt;, &lt; float 5, float 0 &gt;
4273
4274 <i>; yields: result=&lt;2 x i64&gt; &lt; i64 -1, i64 0 &gt;</i>
4275 &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]4276</pre>
4277</div>
4278
4279<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4280<div class="doc_subsubsection">
4281 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4282</div>
4283
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4284<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4285
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4286<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4287
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4288<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4289<h5>Overview:</h5>
4290<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4291the SSA graph representing the function.</p>
4292<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4293
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4294<p>The type of the incoming values is specified with the first type
4295field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4296as arguments, with one pair for each predecessor basic block of the
4297current block. Only values of <a href="#t_firstclass">first class</a>
4298type may be used as the value arguments to the PHI node. Only labels
4299may be used as the label arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4300
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4301<p>There must be no non-phi instructions between the start of a basic
4302block and the PHI instructions: i.e. PHI instructions must be first in
4303a basic block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4304
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4305<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4306
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4307<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4308specified by the pair corresponding to the predecessor basic block that executed
4309just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4310
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4311<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4312<pre>
4313Loop: ; Infinite loop that counts from 0 on up...
4314 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4315 %nextindvar = add i32 %indvar, 1
4316 br label %Loop
4317</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4318</div>
4319
4320<!-- _______________________________________________________________________ -->
4321<div class="doc_subsubsection">
4322 <a name="i_select">'<tt>select</tt>' Instruction</a>
4323</div>
4324
4325<div class="doc_text">
4326
4327<h5>Syntax:</h5>
4328
4329<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4330 &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>
4331
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4332 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4333</pre>
4334
4335<h5>Overview:</h5>
4336
4337<p>
4338The '<tt>select</tt>' instruction is used to choose one value based on a
4339condition, without branching.
4340</p>
4341
4342
4343<h5>Arguments:</h5>
4344
4345<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4346The '<tt>select</tt>' instruction requires an 'i1' value or
4347a vector of 'i1' values indicating the
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4348condition, and two values of the same <a href="#t_firstclass">first class</a>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4349type. If the val1/val2 are vectors and
4350the condition is a scalar, then entire vectors are selected, not
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4351individual elements.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4352</p>
4353
4354<h5>Semantics:</h5>
4355
4356<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4357If 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]4358value argument; otherwise, it returns the second value argument.
4359</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4360<p>
4361If the condition is a vector of i1, then the value arguments must
4362be vectors of the same size, and the selection is done element
4363by element.
4364</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4365
4366<h5>Example:</h5>
4367
4368<pre>
4369 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4370</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame^]4371
4372<p>Note that the code generator does not yet support conditions
4373 with vector type.</p>
4374
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4375</div>
4376
4377
4378<!-- _______________________________________________________________________ -->
4379<div class="doc_subsubsection">
4380 <a name="i_call">'<tt>call</tt>' Instruction</a>
4381</div>
4382
4383<div class="doc_text">
4384
4385<h5>Syntax:</h5>
4386<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4387 &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]4388</pre>
4389
4390<h5>Overview:</h5>
4391
4392<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4393
4394<h5>Arguments:</h5>
4395
4396<p>This instruction requires several arguments:</p>
4397
4398<ol>
4399 <li>
4400 <p>The optional "tail" marker indicates whether the callee function accesses
4401 any allocas or varargs in the caller. If the "tail" marker is present, the
4402 function call is eligible for tail call optimization. Note that calls may
4403 be marked "tail" even if they do not occur before a <a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4404 href="#i_ret"><tt>ret</tt></a> instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4405 </li>
4406 <li>
4407 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
4408 convention</a> the call should use. If none is specified, the call defaults
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4409 to using C calling conventions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4410 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4411
4412 <li>
4413 <p>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4414 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
4415 and '<tt>inreg</tt>' attributes are valid here.</p>
4416 </li>
4417
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4418 <li>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4419 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4420 the type of the return value. Functions that return no value are marked
4421 <tt><a href="#t_void">void</a></tt>.</p>
4422 </li>
4423 <li>
4424 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4425 value being invoked. The argument types must match the types implied by
4426 this signature. This type can be omitted if the function is not varargs
4427 and if the function type does not return a pointer to a function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4428 </li>
4429 <li>
4430 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4431 be invoked. In most cases, this is a direct function invocation, but
4432 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4433 to function value.</p>
4434 </li>
4435 <li>
4436 <p>'<tt>function args</tt>': argument list whose types match the
4437 function signature argument types. All arguments must be of
4438 <a href="#t_firstclass">first class</a> type. If the function signature
4439 indicates the function accepts a variable number of arguments, the extra
4440 arguments can be specified.</p>
4441 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4442 <li>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4443 <p>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4444 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4445 '<tt>readnone</tt>' attributes are valid here.</p>
4446 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4447</ol>
4448
4449<h5>Semantics:</h5>
4450
4451<p>The '<tt>call</tt>' instruction is used to cause control flow to
4452transfer to a specified function, with its incoming arguments bound to
4453the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4454instruction in the called function, control flow continues with the
4455instruction after the function call, and the return value of the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4456function is bound to the result argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4457
4458<h5>Example:</h5>
4459
4460<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4461 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4462 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4463 %X = tail call i32 @foo() <i>; yields i32</i>
4464 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4465 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4466
4467 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4468 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]4469 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4470 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]4471 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]4472 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4473</pre>
4474
4475</div>
4476
4477<!-- _______________________________________________________________________ -->
4478<div class="doc_subsubsection">
4479 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4480</div>
4481
4482<div class="doc_text">
4483
4484<h5>Syntax:</h5>
4485
4486<pre>
4487 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4488</pre>
4489
4490<h5>Overview:</h5>
4491
4492<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
4493the "variable argument" area of a function call. It is used to implement the
4494<tt>va_arg</tt> macro in C.</p>
4495
4496<h5>Arguments:</h5>
4497
4498<p>This instruction takes a <tt>va_list*</tt> value and the type of
4499the argument. It returns a value of the specified argument type and
4500increments the <tt>va_list</tt> to point to the next argument. The
4501actual type of <tt>va_list</tt> is target specific.</p>
4502
4503<h5>Semantics:</h5>
4504
4505<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4506type from the specified <tt>va_list</tt> and causes the
4507<tt>va_list</tt> to point to the next argument. For more information,
4508see the variable argument handling <a href="#int_varargs">Intrinsic
4509Functions</a>.</p>
4510
4511<p>It is legal for this instruction to be called in a function which does not
4512take a variable number of arguments, for example, the <tt>vfprintf</tt>
4513function.</p>
4514
4515<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
4516href="#intrinsics">intrinsic function</a> because it takes a type as an
4517argument.</p>
4518
4519<h5>Example:</h5>
4520
4521<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4522
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]4523<p>Note that the code generator does not yet fully support va_arg
4524 on many targets. Also, it does not currently support va_arg with
4525 aggregate types on any target.</p>
4526
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4527</div>
4528
4529<!-- *********************************************************************** -->
4530<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4531<!-- *********************************************************************** -->
4532
4533<div class="doc_text">
4534
4535<p>LLVM supports the notion of an "intrinsic function". These functions have
4536well known names and semantics and are required to follow certain restrictions.
4537Overall, these intrinsics represent an extension mechanism for the LLVM
4538language that does not require changing all of the transformations in LLVM when
4539adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
4540
4541<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
4542prefix is reserved in LLVM for intrinsic names; thus, function names may not
4543begin with this prefix. Intrinsic functions must always be external functions:
4544you cannot define the body of intrinsic functions. Intrinsic functions may
4545only be used in call or invoke instructions: it is illegal to take the address
4546of an intrinsic function. Additionally, because intrinsic functions are part
4547of the LLVM language, it is required if any are added that they be documented
4548here.</p>
4549
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4550<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4551a family of functions that perform the same operation but on different data
4552types. Because LLVM can represent over 8 million different integer types,
4553overloading is used commonly to allow an intrinsic function to operate on any
4554integer type. One or more of the argument types or the result type can be
4555overloaded to accept any integer type. Argument types may also be defined as
4556exactly matching a previous argument's type or the result type. This allows an
4557intrinsic function which accepts multiple arguments, but needs all of them to
4558be of the same type, to only be overloaded with respect to a single argument or
4559the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4560
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4561<p>Overloaded intrinsics will have the names of its overloaded argument types
4562encoded into its function name, each preceded by a period. Only those types
4563which are overloaded result in a name suffix. Arguments whose type is matched
4564against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4565take an integer of any width and returns an integer of exactly the same integer
4566width. This leads to a family of functions such as
4567<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4568Only one type, the return type, is overloaded, and only one type suffix is
4569required. Because the argument's type is matched against the return type, it
4570does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4571
4572<p>To learn how to add an intrinsic function, please see the
4573<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
4574</p>
4575
4576</div>
4577
4578<!-- ======================================================================= -->
4579<div class="doc_subsection">
4580 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4581</div>
4582
4583<div class="doc_text">
4584
4585<p>Variable argument support is defined in LLVM with the <a
4586 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4587intrinsic functions. These functions are related to the similarly
4588named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
4589
4590<p>All of these functions operate on arguments that use a
4591target-specific value type "<tt>va_list</tt>". The LLVM assembly
4592language reference manual does not define what this type is, so all
4593transformations should be prepared to handle these functions regardless of
4594the type used.</p>
4595
4596<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
4597instruction and the variable argument handling intrinsic functions are
4598used.</p>
4599
4600<div class="doc_code">
4601<pre>
4602define i32 @test(i32 %X, ...) {
4603 ; Initialize variable argument processing
4604 %ap = alloca i8*
4605 %ap2 = bitcast i8** %ap to i8*
4606 call void @llvm.va_start(i8* %ap2)
4607
4608 ; Read a single integer argument
4609 %tmp = va_arg i8** %ap, i32
4610
4611 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4612 %aq = alloca i8*
4613 %aq2 = bitcast i8** %aq to i8*
4614 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4615 call void @llvm.va_end(i8* %aq2)
4616
4617 ; Stop processing of arguments.
4618 call void @llvm.va_end(i8* %ap2)
4619 ret i32 %tmp
4620}
4621
4622declare void @llvm.va_start(i8*)
4623declare void @llvm.va_copy(i8*, i8*)
4624declare void @llvm.va_end(i8*)
4625</pre>
4626</div>
4627
4628</div>
4629
4630<!-- _______________________________________________________________________ -->
4631<div class="doc_subsubsection">
4632 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4633</div>
4634
4635
4636<div class="doc_text">
4637<h5>Syntax:</h5>
4638<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
4639<h5>Overview:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4640<p>The '<tt>llvm.va_start</tt>' intrinsic initializes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4641<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4642href="#i_va_arg">va_arg</a></tt>.</p>
4643
4644<h5>Arguments:</h5>
4645
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4646<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]4647
4648<h5>Semantics:</h5>
4649
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4650<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]4651macro available in C. In a target-dependent way, it initializes the
4652<tt>va_list</tt> element to which the argument points, so that the next call to
4653<tt>va_arg</tt> will produce the first variable argument passed to the function.
4654Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
4655last argument of the function as the compiler can figure that out.</p>
4656
4657</div>
4658
4659<!-- _______________________________________________________________________ -->
4660<div class="doc_subsubsection">
4661 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
4662</div>
4663
4664<div class="doc_text">
4665<h5>Syntax:</h5>
4666<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
4667<h5>Overview:</h5>
4668
4669<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
4670which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
4671or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
4672
4673<h5>Arguments:</h5>
4674
4675<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
4676
4677<h5>Semantics:</h5>
4678
4679<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
4680macro available in C. In a target-dependent way, it destroys the
4681<tt>va_list</tt> element to which the argument points. Calls to <a
4682href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4683<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4684<tt>llvm.va_end</tt>.</p>
4685
4686</div>
4687
4688<!-- _______________________________________________________________________ -->
4689<div class="doc_subsubsection">
4690 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
4691</div>
4692
4693<div class="doc_text">
4694
4695<h5>Syntax:</h5>
4696
4697<pre>
4698 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
4699</pre>
4700
4701<h5>Overview:</h5>
4702
4703<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4704from the source argument list to the destination argument list.</p>
4705
4706<h5>Arguments:</h5>
4707
4708<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
4709The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
4710
4711
4712<h5>Semantics:</h5>
4713
4714<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4715macro available in C. In a target-dependent way, it copies the source
4716<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4717intrinsic is necessary because the <tt><a href="#int_va_start">
4718llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4719example, memory allocation.</p>
4720
4721</div>
4722
4723<!-- ======================================================================= -->
4724<div class="doc_subsection">
4725 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4726</div>
4727
4728<div class="doc_text">
4729
4730<p>
4731LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]4732Collection</a> (GC) requires the implementation and generation of these
4733intrinsics.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4734These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
4735stack</a>, as well as garbage collector implementations that require <a
4736href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
4737Front-ends for type-safe garbage collected languages should generate these
4738intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4739href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4740</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]4741
4742<p>The garbage collection intrinsics only operate on objects in the generic
4743 address space (address space zero).</p>
4744
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4745</div>
4746
4747<!-- _______________________________________________________________________ -->
4748<div class="doc_subsubsection">
4749 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
4750</div>
4751
4752<div class="doc_text">
4753
4754<h5>Syntax:</h5>
4755
4756<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4757 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4758</pre>
4759
4760<h5>Overview:</h5>
4761
4762<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
4763the code generator, and allows some metadata to be associated with it.</p>
4764
4765<h5>Arguments:</h5>
4766
4767<p>The first argument specifies the address of a stack object that contains the
4768root pointer. The second pointer (which must be either a constant or a global
4769value address) contains the meta-data to be associated with the root.</p>
4770
4771<h5>Semantics:</h5>
4772
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]4773<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]4774location. At compile-time, the code generator generates information to allow
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4775the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4776intrinsic may only be used in a function which <a href="#gc">specifies a GC
4777algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4778
4779</div>
4780
4781
4782<!-- _______________________________________________________________________ -->
4783<div class="doc_subsubsection">
4784 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
4785</div>
4786
4787<div class="doc_text">
4788
4789<h5>Syntax:</h5>
4790
4791<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4792 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4793</pre>
4794
4795<h5>Overview:</h5>
4796
4797<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4798locations, allowing garbage collector implementations that require read
4799barriers.</p>
4800
4801<h5>Arguments:</h5>
4802
4803<p>The second argument is the address to read from, which should be an address
4804allocated from the garbage collector. The first object is a pointer to the
4805start of the referenced object, if needed by the language runtime (otherwise
4806null).</p>
4807
4808<h5>Semantics:</h5>
4809
4810<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4811instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4812garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4813may only be used in a function which <a href="#gc">specifies a GC
4814algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4815
4816</div>
4817
4818
4819<!-- _______________________________________________________________________ -->
4820<div class="doc_subsubsection">
4821 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
4822</div>
4823
4824<div class="doc_text">
4825
4826<h5>Syntax:</h5>
4827
4828<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4829 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4830</pre>
4831
4832<h5>Overview:</h5>
4833
4834<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4835locations, allowing garbage collector implementations that require write
4836barriers (such as generational or reference counting collectors).</p>
4837
4838<h5>Arguments:</h5>
4839
4840<p>The first argument is the reference to store, the second is the start of the
4841object to store it to, and the third is the address of the field of Obj to
4842store to. If the runtime does not require a pointer to the object, Obj may be
4843null.</p>
4844
4845<h5>Semantics:</h5>
4846
4847<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4848instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4849garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4850may only be used in a function which <a href="#gc">specifies a GC
4851algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4852
4853</div>
4854
4855
4856
4857<!-- ======================================================================= -->
4858<div class="doc_subsection">
4859 <a name="int_codegen">Code Generator Intrinsics</a>
4860</div>
4861
4862<div class="doc_text">
4863<p>
4864These intrinsics are provided by LLVM to expose special features that may only
4865be implemented with code generator support.
4866</p>
4867
4868</div>
4869
4870<!-- _______________________________________________________________________ -->
4871<div class="doc_subsubsection">
4872 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
4873</div>
4874
4875<div class="doc_text">
4876
4877<h5>Syntax:</h5>
4878<pre>
4879 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
4880</pre>
4881
4882<h5>Overview:</h5>
4883
4884<p>
4885The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4886target-specific value indicating the return address of the current function
4887or one of its callers.
4888</p>
4889
4890<h5>Arguments:</h5>
4891
4892<p>
4893The argument to this intrinsic indicates which function to return the address
4894for. Zero indicates the calling function, one indicates its caller, etc. The
4895argument is <b>required</b> to be a constant integer value.
4896</p>
4897
4898<h5>Semantics:</h5>
4899
4900<p>
4901The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4902the return address of the specified call frame, or zero if it cannot be
4903identified. The value returned by this intrinsic is likely to be incorrect or 0
4904for arguments other than zero, so it should only be used for debugging purposes.
4905</p>
4906
4907<p>
4908Note that calling this intrinsic does not prevent function inlining or other
4909aggressive transformations, so the value returned may not be that of the obvious
4910source-language caller.
4911</p>
4912</div>
4913
4914
4915<!-- _______________________________________________________________________ -->
4916<div class="doc_subsubsection">
4917 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
4918</div>
4919
4920<div class="doc_text">
4921
4922<h5>Syntax:</h5>
4923<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4924 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4925</pre>
4926
4927<h5>Overview:</h5>
4928
4929<p>
4930The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4931target-specific frame pointer value for the specified stack frame.
4932</p>
4933
4934<h5>Arguments:</h5>
4935
4936<p>
4937The argument to this intrinsic indicates which function to return the frame
4938pointer for. Zero indicates the calling function, one indicates its caller,
4939etc. The argument is <b>required</b> to be a constant integer value.
4940</p>
4941
4942<h5>Semantics:</h5>
4943
4944<p>
4945The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4946the frame address of the specified call frame, or zero if it cannot be
4947identified. The value returned by this intrinsic is likely to be incorrect or 0
4948for arguments other than zero, so it should only be used for debugging purposes.
4949</p>
4950
4951<p>
4952Note that calling this intrinsic does not prevent function inlining or other
4953aggressive transformations, so the value returned may not be that of the obvious
4954source-language caller.
4955</p>
4956</div>
4957
4958<!-- _______________________________________________________________________ -->
4959<div class="doc_subsubsection">
4960 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
4961</div>
4962
4963<div class="doc_text">
4964
4965<h5>Syntax:</h5>
4966<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4967 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4968</pre>
4969
4970<h5>Overview:</h5>
4971
4972<p>
4973The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
4974the function stack, for use with <a href="#int_stackrestore">
4975<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4976features like scoped automatic variable sized arrays in C99.
4977</p>
4978
4979<h5>Semantics:</h5>
4980
4981<p>
4982This intrinsic returns a opaque pointer value that can be passed to <a
4983href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
4984<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4985<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4986state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4987practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4988that were allocated after the <tt>llvm.stacksave</tt> was executed.
4989</p>
4990
4991</div>
4992
4993<!-- _______________________________________________________________________ -->
4994<div class="doc_subsubsection">
4995 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
4996</div>
4997
4998<div class="doc_text">
4999
5000<h5>Syntax:</h5>
5001<pre>
5002 declare void @llvm.stackrestore(i8 * %ptr)
5003</pre>
5004
5005<h5>Overview:</h5>
5006
5007<p>
5008The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5009the function stack to the state it was in when the corresponding <a
5010href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
5011useful for implementing language features like scoped automatic variable sized
5012arrays in C99.
5013</p>
5014
5015<h5>Semantics:</h5>
5016
5017<p>
5018See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
5019</p>
5020
5021</div>
5022
5023
5024<!-- _______________________________________________________________________ -->
5025<div class="doc_subsubsection">
5026 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5027</div>
5028
5029<div class="doc_text">
5030
5031<h5>Syntax:</h5>
5032<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5033 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]5034</pre>
5035
5036<h5>Overview:</h5>
5037
5038
5039<p>
5040The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
5041a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
5042no
5043effect on the behavior of the program but can change its performance
5044characteristics.
5045</p>
5046
5047<h5>Arguments:</h5>
5048
5049<p>
5050<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
5051determining if the fetch should be for a read (0) or write (1), and
5052<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5053locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
5054<tt>locality</tt> arguments must be constant integers.
5055</p>
5056
5057<h5>Semantics:</h5>
5058
5059<p>
5060This intrinsic does not modify the behavior of the program. In particular,
5061prefetches cannot trap and do not produce a value. On targets that support this
5062intrinsic, the prefetch can provide hints to the processor cache for better
5063performance.
5064</p>
5065
5066</div>
5067
5068<!-- _______________________________________________________________________ -->
5069<div class="doc_subsubsection">
5070 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5071</div>
5072
5073<div class="doc_text">
5074
5075<h5>Syntax:</h5>
5076<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5077 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5078</pre>
5079
5080<h5>Overview:</h5>
5081
5082
5083<p>
5084The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5085(PC) in a region of
5086code to simulators and other tools. The method is target specific, but it is
5087expected that the marker will use exported symbols to transmit the PC of the
5088marker.
5089The marker makes no guarantees that it will remain with any specific instruction
5090after optimizations. It is possible that the presence of a marker will inhibit
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5091optimizations. The intended use is to be inserted after optimizations to allow
5092correlations of simulation runs.
5093</p>
5094
5095<h5>Arguments:</h5>
5096
5097<p>
5098<tt>id</tt> is a numerical id identifying the marker.
5099</p>
5100
5101<h5>Semantics:</h5>
5102
5103<p>
5104This intrinsic does not modify the behavior of the program. Backends that do not
5105support this intrinisic may ignore it.
5106</p>
5107
5108</div>
5109
5110<!-- _______________________________________________________________________ -->
5111<div class="doc_subsubsection">
5112 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5113</div>
5114
5115<div class="doc_text">
5116
5117<h5>Syntax:</h5>
5118<pre>
5119 declare i64 @llvm.readcyclecounter( )
5120</pre>
5121
5122<h5>Overview:</h5>
5123
5124
5125<p>
5126The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5127counter register (or similar low latency, high accuracy clocks) on those targets
5128that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
5129As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
5130should only be used for small timings.
5131</p>
5132
5133<h5>Semantics:</h5>
5134
5135<p>
5136When directly supported, reading the cycle counter should not modify any memory.
5137Implementations are allowed to either return a application specific value or a
5138system wide value. On backends without support, this is lowered to a constant 0.
5139</p>
5140
5141</div>
5142
5143<!-- ======================================================================= -->
5144<div class="doc_subsection">
5145 <a name="int_libc">Standard C Library Intrinsics</a>
5146</div>
5147
5148<div class="doc_text">
5149<p>
5150LLVM provides intrinsics for a few important standard C library functions.
5151These intrinsics allow source-language front-ends to pass information about the
5152alignment of the pointer arguments to the code generator, providing opportunity
5153for more efficient code generation.
5154</p>
5155
5156</div>
5157
5158<!-- _______________________________________________________________________ -->
5159<div class="doc_subsubsection">
5160 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5161</div>
5162
5163<div class="doc_text">
5164
5165<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5166<p>This is an overloaded intrinsic. You can use llvm.memcpy on any integer bit
5167width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5168<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5169 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5170 i8 &lt;len&gt;, i32 &lt;align&gt;)
5171 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5172 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5173 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5174 i32 &lt;len&gt;, i32 &lt;align&gt;)
5175 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5176 i64 &lt;len&gt;, i32 &lt;align&gt;)
5177</pre>
5178
5179<h5>Overview:</h5>
5180
5181<p>
5182The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5183location to the destination location.
5184</p>
5185
5186<p>
5187Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5188intrinsics do not return a value, and takes an extra alignment argument.
5189</p>
5190
5191<h5>Arguments:</h5>
5192
5193<p>
5194The first argument is a pointer to the destination, the second is a pointer to
5195the source. The third argument is an integer argument
5196specifying the number of bytes to copy, and the fourth argument is the alignment
5197of the source and destination locations.
5198</p>
5199
5200<p>
5201If the call to this intrinisic has an alignment value that is not 0 or 1, then
5202the caller guarantees that both the source and destination pointers are aligned
5203to that boundary.
5204</p>
5205
5206<h5>Semantics:</h5>
5207
5208<p>
5209The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5210location to the destination location, which are not allowed to overlap. It
5211copies "len" bytes of memory over. If the argument is known to be aligned to
5212some boundary, this can be specified as the fourth argument, otherwise it should
5213be set to 0 or 1.
5214</p>
5215</div>
5216
5217
5218<!-- _______________________________________________________________________ -->
5219<div class="doc_subsubsection">
5220 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5221</div>
5222
5223<div class="doc_text">
5224
5225<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5226<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
5227width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5228<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5229 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5230 i8 &lt;len&gt;, i32 &lt;align&gt;)
5231 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5232 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5233 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5234 i32 &lt;len&gt;, i32 &lt;align&gt;)
5235 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5236 i64 &lt;len&gt;, i32 &lt;align&gt;)
5237</pre>
5238
5239<h5>Overview:</h5>
5240
5241<p>
5242The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5243location to the destination location. It is similar to the
Chris Lattnerdba16ea2008-01-06 19:51:52 +0000[diff] [blame]5244'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5245</p>
5246
5247<p>
5248Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5249intrinsics do not return a value, and takes an extra alignment argument.
5250</p>
5251
5252<h5>Arguments:</h5>
5253
5254<p>
5255The first argument is a pointer to the destination, the second is a pointer to
5256the source. The third argument is an integer argument
5257specifying the number of bytes to copy, and the fourth argument is the alignment
5258of the source and destination locations.
5259</p>
5260
5261<p>
5262If the call to this intrinisic has an alignment value that is not 0 or 1, then
5263the caller guarantees that the source and destination pointers are aligned to
5264that boundary.
5265</p>
5266
5267<h5>Semantics:</h5>
5268
5269<p>
5270The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
5271location to the destination location, which may overlap. It
5272copies "len" bytes of memory over. If the argument is known to be aligned to
5273some boundary, this can be specified as the fourth argument, otherwise it should
5274be set to 0 or 1.
5275</p>
5276</div>
5277
5278
5279<!-- _______________________________________________________________________ -->
5280<div class="doc_subsubsection">
5281 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5282</div>
5283
5284<div class="doc_text">
5285
5286<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5287<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
5288width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5289<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5290 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5291 i8 &lt;len&gt;, i32 &lt;align&gt;)
5292 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5293 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5294 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5295 i32 &lt;len&gt;, i32 &lt;align&gt;)
5296 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5297 i64 &lt;len&gt;, i32 &lt;align&gt;)
5298</pre>
5299
5300<h5>Overview:</h5>
5301
5302<p>
5303The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
5304byte value.
5305</p>
5306
5307<p>
5308Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5309does not return a value, and takes an extra alignment argument.
5310</p>
5311
5312<h5>Arguments:</h5>
5313
5314<p>
5315The first argument is a pointer to the destination to fill, the second is the
5316byte value to fill it with, the third argument is an integer
5317argument specifying the number of bytes to fill, and the fourth argument is the
5318known alignment of destination location.
5319</p>
5320
5321<p>
5322If the call to this intrinisic has an alignment value that is not 0 or 1, then
5323the caller guarantees that the destination pointer is aligned to that boundary.
5324</p>
5325
5326<h5>Semantics:</h5>
5327
5328<p>
5329The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5330the
5331destination location. If the argument is known to be aligned to some boundary,
5332this can be specified as the fourth argument, otherwise it should be set to 0 or
53331.
5334</p>
5335</div>
5336
5337
5338<!-- _______________________________________________________________________ -->
5339<div class="doc_subsubsection">
5340 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5341</div>
5342
5343<div class="doc_text">
5344
5345<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5346<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]5347floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5348types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5349<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5350 declare float @llvm.sqrt.f32(float %Val)
5351 declare double @llvm.sqrt.f64(double %Val)
5352 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5353 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5354 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5355</pre>
5356
5357<h5>Overview:</h5>
5358
5359<p>
5360The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5361returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5362<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattnerf914a002008-01-29 07:00:44 +0000[diff] [blame]5363negative numbers other than -0.0 (which allows for better optimization, because
5364there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5365defined to return -0.0 like IEEE sqrt.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5366</p>
5367
5368<h5>Arguments:</h5>
5369
5370<p>
5371The argument and return value are floating point numbers of the same type.
5372</p>
5373
5374<h5>Semantics:</h5>
5375
5376<p>
5377This function returns the sqrt of the specified operand if it is a nonnegative
5378floating point number.
5379</p>
5380</div>
5381
5382<!-- _______________________________________________________________________ -->
5383<div class="doc_subsubsection">
5384 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5385</div>
5386
5387<div class="doc_text">
5388
5389<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5390<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]5391floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5392types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5393<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5394 declare float @llvm.powi.f32(float %Val, i32 %power)
5395 declare double @llvm.powi.f64(double %Val, i32 %power)
5396 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5397 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5398 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5399</pre>
5400
5401<h5>Overview:</h5>
5402
5403<p>
5404The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5405specified (positive or negative) power. The order of evaluation of
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5406multiplications is not defined. When a vector of floating point type is
5407used, the second argument remains a scalar integer value.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5408</p>
5409
5410<h5>Arguments:</h5>
5411
5412<p>
5413The second argument is an integer power, and the first is a value to raise to
5414that power.
5415</p>
5416
5417<h5>Semantics:</h5>
5418
5419<p>
5420This function returns the first value raised to the second power with an
5421unspecified sequence of rounding operations.</p>
5422</div>
5423
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5424<!-- _______________________________________________________________________ -->
5425<div class="doc_subsubsection">
5426 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5427</div>
5428
5429<div class="doc_text">
5430
5431<h5>Syntax:</h5>
5432<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5433floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5434types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5435<pre>
5436 declare float @llvm.sin.f32(float %Val)
5437 declare double @llvm.sin.f64(double %Val)
5438 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5439 declare fp128 @llvm.sin.f128(fp128 %Val)
5440 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5441</pre>
5442
5443<h5>Overview:</h5>
5444
5445<p>
5446The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5447</p>
5448
5449<h5>Arguments:</h5>
5450
5451<p>
5452The argument and return value are floating point numbers of the same type.
5453</p>
5454
5455<h5>Semantics:</h5>
5456
5457<p>
5458This function returns the sine of the specified operand, returning the
5459same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5460conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5461</div>
5462
5463<!-- _______________________________________________________________________ -->
5464<div class="doc_subsubsection">
5465 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5466</div>
5467
5468<div class="doc_text">
5469
5470<h5>Syntax:</h5>
5471<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5472floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5473types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5474<pre>
5475 declare float @llvm.cos.f32(float %Val)
5476 declare double @llvm.cos.f64(double %Val)
5477 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5478 declare fp128 @llvm.cos.f128(fp128 %Val)
5479 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5480</pre>
5481
5482<h5>Overview:</h5>
5483
5484<p>
5485The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5486</p>
5487
5488<h5>Arguments:</h5>
5489
5490<p>
5491The argument and return value are floating point numbers of the same type.
5492</p>
5493
5494<h5>Semantics:</h5>
5495
5496<p>
5497This function returns the cosine of the specified operand, returning the
5498same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5499conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5500</div>
5501
5502<!-- _______________________________________________________________________ -->
5503<div class="doc_subsubsection">
5504 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5505</div>
5506
5507<div class="doc_text">
5508
5509<h5>Syntax:</h5>
5510<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5511floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5512types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5513<pre>
5514 declare float @llvm.pow.f32(float %Val, float %Power)
5515 declare double @llvm.pow.f64(double %Val, double %Power)
5516 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5517 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5518 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5519</pre>
5520
5521<h5>Overview:</h5>
5522
5523<p>
5524The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5525specified (positive or negative) power.
5526</p>
5527
5528<h5>Arguments:</h5>
5529
5530<p>
5531The second argument is a floating point power, and the first is a value to
5532raise to that power.
5533</p>
5534
5535<h5>Semantics:</h5>
5536
5537<p>
5538This function returns the first value raised to the second power,
5539returning the
5540same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5541conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5542</div>
5543
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5544
5545<!-- ======================================================================= -->
5546<div class="doc_subsection">
5547 <a name="int_manip">Bit Manipulation Intrinsics</a>
5548</div>
5549
5550<div class="doc_text">
5551<p>
5552LLVM provides intrinsics for a few important bit manipulation operations.
5553These allow efficient code generation for some algorithms.
5554</p>
5555
5556</div>
5557
5558<!-- _______________________________________________________________________ -->
5559<div class="doc_subsubsection">
5560 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5561</div>
5562
5563<div class="doc_text">
5564
5565<h5>Syntax:</h5>
5566<p>This is an overloaded intrinsic function. You can use bswap on any integer
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5567type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5568<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5569 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5570 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5571 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5572</pre>
5573
5574<h5>Overview:</h5>
5575
5576<p>
5577The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5578values with an even number of bytes (positive multiple of 16 bits). These are
5579useful for performing operations on data that is not in the target's native
5580byte order.
5581</p>
5582
5583<h5>Semantics:</h5>
5584
5585<p>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5586The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5587and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5588intrinsic returns an i32 value that has the four bytes of the input i32
5589swapped, 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]5590i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5591<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5592additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
5593</p>
5594
5595</div>
5596
5597<!-- _______________________________________________________________________ -->
5598<div class="doc_subsubsection">
5599 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5600</div>
5601
5602<div class="doc_text">
5603
5604<h5>Syntax:</h5>
5605<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]5606width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5607<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5608 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
5609 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5610 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5611 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5612 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5613</pre>
5614
5615<h5>Overview:</h5>
5616
5617<p>
5618The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5619value.
5620</p>
5621
5622<h5>Arguments:</h5>
5623
5624<p>
5625The only argument is the value to be counted. The argument may be of any
5626integer type. The return type must match the argument type.
5627</p>
5628
5629<h5>Semantics:</h5>
5630
5631<p>
5632The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5633</p>
5634</div>
5635
5636<!-- _______________________________________________________________________ -->
5637<div class="doc_subsubsection">
5638 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5639</div>
5640
5641<div class="doc_text">
5642
5643<h5>Syntax:</h5>
5644<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]5645integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5646<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5647 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5648 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5649 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5650 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5651 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5652</pre>
5653
5654<h5>Overview:</h5>
5655
5656<p>
5657The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5658leading zeros in a variable.
5659</p>
5660
5661<h5>Arguments:</h5>
5662
5663<p>
5664The only argument is the value to be counted. The argument may be of any
5665integer type. The return type must match the argument type.
5666</p>
5667
5668<h5>Semantics:</h5>
5669
5670<p>
5671The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5672in a variable. If the src == 0 then the result is the size in bits of the type
5673of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
5674</p>
5675</div>
5676
5677
5678
5679<!-- _______________________________________________________________________ -->
5680<div class="doc_subsubsection">
5681 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5682</div>
5683
5684<div class="doc_text">
5685
5686<h5>Syntax:</h5>
5687<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]5688integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5689<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5690 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5691 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5692 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5693 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5694 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5695</pre>
5696
5697<h5>Overview:</h5>
5698
5699<p>
5700The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5701trailing zeros.
5702</p>
5703
5704<h5>Arguments:</h5>
5705
5706<p>
5707The only argument is the value to be counted. The argument may be of any
5708integer type. The return type must match the argument type.
5709</p>
5710
5711<h5>Semantics:</h5>
5712
5713<p>
5714The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5715in a variable. If the src == 0 then the result is the size in bits of the type
5716of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5717</p>
5718</div>
5719
5720<!-- _______________________________________________________________________ -->
5721<div class="doc_subsubsection">
5722 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
5723</div>
5724
5725<div class="doc_text">
5726
5727<h5>Syntax:</h5>
5728<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5729on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5730<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5731 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5732 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5733</pre>
5734
5735<h5>Overview:</h5>
5736<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
5737range of bits from an integer value and returns them in the same bit width as
5738the original value.</p>
5739
5740<h5>Arguments:</h5>
5741<p>The first argument, <tt>%val</tt> and the result may be integer types of
5742any bit width but they must have the same bit width. The second and third
5743arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
5744
5745<h5>Semantics:</h5>
5746<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
5747of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5748<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5749operates in forward mode.</p>
5750<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5751right by <tt>%loBit</tt> bits and then ANDing it with a mask with
5752only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5753<ol>
5754 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5755 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5756 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5757 to determine the number of bits to retain.</li>
5758 <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]5759 <li>The mask is ANDed with <tt>%val</tt> to produce the result.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5760</ol>
5761<p>In reverse mode, a similar computation is made except that the bits are
5762returned in the reverse order. So, for example, if <tt>X</tt> has the value
5763<tt>i16 0x0ACF (101011001111)</tt> and we apply
5764<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5765<tt>i16 0x0026 (000000100110)</tt>.</p>
5766</div>
5767
5768<div class="doc_subsubsection">
5769 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5770</div>
5771
5772<div class="doc_text">
5773
5774<h5>Syntax:</h5>
5775<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5776on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5777<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5778 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5779 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]5780</pre>
5781
5782<h5>Overview:</h5>
5783<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5784of bits in an integer value with another integer value. It returns the integer
5785with the replaced bits.</p>
5786
5787<h5>Arguments:</h5>
5788<p>The first argument, <tt>%val</tt> and the result may be integer types of
5789any bit width but they must have the same bit width. <tt>%val</tt> is the value
5790whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5791integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5792type since they specify only a bit index.</p>
5793
5794<h5>Semantics:</h5>
5795<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5796of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5797<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5798operates in forward mode.</p>
5799<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5800truncating it down to the size of the replacement area or zero extending it
5801up to that size.</p>
5802<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5803are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5804in <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]5805to the <tt>%hi</tt>th bit.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5806<p>In reverse mode, a similar computation is made except that the bits are
5807reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5808<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]5809<h5>Examples:</h5>
5810<pre>
5811 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
5812 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5813 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5814 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
5815 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
5816</pre>
5817</div>
5818
5819<!-- ======================================================================= -->
5820<div class="doc_subsection">
5821 <a name="int_debugger">Debugger Intrinsics</a>
5822</div>
5823
5824<div class="doc_text">
5825<p>
5826The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5827are described in the <a
5828href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5829Debugging</a> document.
5830</p>
5831</div>
5832
5833
5834<!-- ======================================================================= -->
5835<div class="doc_subsection">
5836 <a name="int_eh">Exception Handling Intrinsics</a>
5837</div>
5838
5839<div class="doc_text">
5840<p> The LLVM exception handling intrinsics (which all start with
5841<tt>llvm.eh.</tt> prefix), are described in the <a
5842href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5843Handling</a> document. </p>
5844</div>
5845
5846<!-- ======================================================================= -->
5847<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5848 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5849</div>
5850
5851<div class="doc_text">
5852<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5853 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5854 the <tt>nest</tt> attribute, from a function. The result is a callable
5855 function pointer lacking the nest parameter - the caller does not need
5856 to provide a value for it. Instead, the value to use is stored in
5857 advance in a "trampoline", a block of memory usually allocated
5858 on the stack, which also contains code to splice the nest value into the
5859 argument list. This is used to implement the GCC nested function address
5860 extension.
5861</p>
5862<p>
5863 For example, if the function is
5864 <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]5865 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]5866<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5867 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5868 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5869 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5870 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5871</pre>
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]5872 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5873 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5874</div>
5875
5876<!-- _______________________________________________________________________ -->
5877<div class="doc_subsubsection">
5878 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5879</div>
5880<div class="doc_text">
5881<h5>Syntax:</h5>
5882<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5883declare 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]5884</pre>
5885<h5>Overview:</h5>
5886<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5887 This fills the memory pointed to by <tt>tramp</tt> with code
5888 and returns a function pointer suitable for executing it.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5889</p>
5890<h5>Arguments:</h5>
5891<p>
5892 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5893 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5894 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sands35012212007-08-22 23:39:54 +0000[diff] [blame]5895 intrinsic. Note that the size and the alignment are target-specific - LLVM
5896 currently provides no portable way of determining them, so a front-end that
5897 generates this intrinsic needs to have some target-specific knowledge.
5898 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]5899</p>
5900<h5>Semantics:</h5>
5901<p>
5902 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5903 dependent code, turning it into a function. A pointer to this function is
5904 returned, but needs to be bitcast to an
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5905 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5906 before being called. The new function's signature is the same as that of
5907 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5908 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5909 of pointer type. Calling the new function is equivalent to calling
5910 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5911 missing <tt>nest</tt> argument. If, after calling
5912 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5913 modified, then the effect of any later call to the returned function pointer is
5914 undefined.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5915</p>
5916</div>
5917
5918<!-- ======================================================================= -->
5919<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5920 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
5921</div>
5922
5923<div class="doc_text">
5924<p>
5925 These intrinsic functions expand the "universal IR" of LLVM to represent
5926 hardware constructs for atomic operations and memory synchronization. This
5927 provides an interface to the hardware, not an interface to the programmer. It
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5928 is aimed at a low enough level to allow any programming models or APIs
5929 (Application Programming Interfaces) which
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5930 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
5931 hardware behavior. Just as hardware provides a "universal IR" for source
5932 languages, it also provides a starting point for developing a "universal"
5933 atomic operation and synchronization IR.
5934</p>
5935<p>
5936 These do <em>not</em> form an API such as high-level threading libraries,
5937 software transaction memory systems, atomic primitives, and intrinsic
5938 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
5939 application libraries. The hardware interface provided by LLVM should allow
5940 a clean implementation of all of these APIs and parallel programming models.
5941 No one model or paradigm should be selected above others unless the hardware
5942 itself ubiquitously does so.
5943
5944</p>
5945</div>
5946
5947<!-- _______________________________________________________________________ -->
5948<div class="doc_subsubsection">
5949 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5950</div>
5951<div class="doc_text">
5952<h5>Syntax:</h5>
5953<pre>
5954declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
5955i1 &lt;device&gt; )
5956
5957</pre>
5958<h5>Overview:</h5>
5959<p>
5960 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5961 specific pairs of memory access types.
5962</p>
5963<h5>Arguments:</h5>
5964<p>
5965 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
5966 The first four arguments enables a specific barrier as listed below. The fith
5967 argument specifies that the barrier applies to io or device or uncached memory.
5968
5969</p>
5970 <ul>
5971 <li><tt>ll</tt>: load-load barrier</li>
5972 <li><tt>ls</tt>: load-store barrier</li>
5973 <li><tt>sl</tt>: store-load barrier</li>
5974 <li><tt>ss</tt>: store-store barrier</li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5975 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5976 </ul>
5977<h5>Semantics:</h5>
5978<p>
5979 This intrinsic causes the system to enforce some ordering constraints upon
5980 the loads and stores of the program. This barrier does not indicate
5981 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5982 which they occur. For any of the specified pairs of load and store operations
5983 (f.ex. load-load, or store-load), all of the first operations preceding the
5984 barrier will complete before any of the second operations succeeding the
5985 barrier begin. Specifically the semantics for each pairing is as follows:
5986</p>
5987 <ul>
5988 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5989 after the barrier begins.</li>
5990
5991 <li><tt>ls</tt>: All loads before the barrier must complete before any
5992 store after the barrier begins.</li>
5993 <li><tt>ss</tt>: All stores before the barrier must complete before any
5994 store after the barrier begins.</li>
5995 <li><tt>sl</tt>: All stores before the barrier must complete before any
5996 load after the barrier begins.</li>
5997 </ul>
5998<p>
5999 These semantics are applied with a logical "and" behavior when more than one
6000 is enabled in a single memory barrier intrinsic.
6001</p>
6002<p>
6003 Backends may implement stronger barriers than those requested when they do not
6004 support as fine grained a barrier as requested. Some architectures do not
6005 need all types of barriers and on such architectures, these become noops.
6006</p>
6007<h5>Example:</h5>
6008<pre>
6009%ptr = malloc i32
6010 store i32 4, %ptr
6011
6012%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6013 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6014 <i>; guarantee the above finishes</i>
6015 store i32 8, %ptr <i>; before this begins</i>
6016</pre>
6017</div>
6018
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6019<!-- _______________________________________________________________________ -->
6020<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6021 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6022</div>
6023<div class="doc_text">
6024<h5>Syntax:</h5>
6025<p>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6026 This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6027 any integer bit width and for different address spaces. Not all targets
6028 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6029
6030<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6031declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6032declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6033declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6034declare 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]6035
6036</pre>
6037<h5>Overview:</h5>
6038<p>
6039 This loads a value in memory and compares it to a given value. If they are
6040 equal, it stores a new value into the memory.
6041</p>
6042<h5>Arguments:</h5>
6043<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6044 The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6045 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6046 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6047 this integer type. While any bit width integer may be used, targets may only
6048 lower representations they support in hardware.
6049
6050</p>
6051<h5>Semantics:</h5>
6052<p>
6053 This entire intrinsic must be executed atomically. It first loads the value
6054 in memory pointed to by <tt>ptr</tt> and compares it with the value
6055 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
6056 loaded value is yielded in all cases. This provides the equivalent of an
6057 atomic compare-and-swap operation within the SSA framework.
6058</p>
6059<h5>Examples:</h5>
6060
6061<pre>
6062%ptr = malloc i32
6063 store i32 4, %ptr
6064
6065%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6066%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6067 <i>; yields {i32}:result1 = 4</i>
6068%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6069%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6070
6071%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6072%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6073 <i>; yields {i32}:result2 = 8</i>
6074%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6075
6076%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6077</pre>
6078</div>
6079
6080<!-- _______________________________________________________________________ -->
6081<div class="doc_subsubsection">
6082 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6083</div>
6084<div class="doc_text">
6085<h5>Syntax:</h5>
6086
6087<p>
6088 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6089 integer bit width. Not all targets support all bit widths however.</p>
6090<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6091declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6092declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6093declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6094declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6095
6096</pre>
6097<h5>Overview:</h5>
6098<p>
6099 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6100 the value from memory. It then stores the value in <tt>val</tt> in the memory
6101 at <tt>ptr</tt>.
6102</p>
6103<h5>Arguments:</h5>
6104
6105<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6106 The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6107 <tt>val</tt> argument and the result must be integers of the same bit width.
6108 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6109 integer type. The targets may only lower integer representations they
6110 support.
6111</p>
6112<h5>Semantics:</h5>
6113<p>
6114 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6115 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6116 equivalent of an atomic swap operation within the SSA framework.
6117
6118</p>
6119<h5>Examples:</h5>
6120<pre>
6121%ptr = malloc i32
6122 store i32 4, %ptr
6123
6124%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6125%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6126 <i>; yields {i32}:result1 = 4</i>
6127%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6128%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6129
6130%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6131%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6132 <i>; yields {i32}:result2 = 8</i>
6133
6134%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6135%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6136</pre>
6137</div>
6138
6139<!-- _______________________________________________________________________ -->
6140<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6141 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6142
6143</div>
6144<div class="doc_text">
6145<h5>Syntax:</h5>
6146<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6147 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]6148 integer bit width. Not all targets support all bit widths however.</p>
6149<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6150declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6151declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6152declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6153declare 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]6154
6155</pre>
6156<h5>Overview:</h5>
6157<p>
6158 This intrinsic adds <tt>delta</tt> to the value stored in memory at
6159 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6160</p>
6161<h5>Arguments:</h5>
6162<p>
6163
6164 The intrinsic takes two arguments, the first a pointer to an integer value
6165 and the second an integer value. The result is also an integer value. These
6166 integer types can have any bit width, but they must all have the same bit
6167 width. The targets may only lower integer representations they support.
6168</p>
6169<h5>Semantics:</h5>
6170<p>
6171 This intrinsic does a series of operations atomically. It first loads the
6172 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6173 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6174</p>
6175
6176<h5>Examples:</h5>
6177<pre>
6178%ptr = malloc i32
6179 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6180%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6181 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6182%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6183 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6184%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6185 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6186%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6187</pre>
6188</div>
6189
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6190<!-- _______________________________________________________________________ -->
6191<div class="doc_subsubsection">
6192 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6193
6194</div>
6195<div class="doc_text">
6196<h5>Syntax:</h5>
6197<p>
6198 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]6199 any integer bit width and for different address spaces. Not all targets
6200 support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6201<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6202declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6203declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6204declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6205declare 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]6206
6207</pre>
6208<h5>Overview:</h5>
6209<p>
6210 This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6211 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6212</p>
6213<h5>Arguments:</h5>
6214<p>
6215
6216 The intrinsic takes two arguments, the first a pointer to an integer value
6217 and the second an integer value. The result is also an integer value. These
6218 integer types can have any bit width, but they must all have the same bit
6219 width. The targets may only lower integer representations they support.
6220</p>
6221<h5>Semantics:</h5>
6222<p>
6223 This intrinsic does a series of operations atomically. It first loads the
6224 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6225 result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6226</p>
6227
6228<h5>Examples:</h5>
6229<pre>
6230%ptr = malloc i32
6231 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6232%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6233 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6234%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6235 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6236%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6237 <i>; yields {i32}:result3 = 2</i>
6238%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6239</pre>
6240</div>
6241
6242<!-- _______________________________________________________________________ -->
6243<div class="doc_subsubsection">
6244 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6245 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6246 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6247 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
6248
6249</div>
6250<div class="doc_text">
6251<h5>Syntax:</h5>
6252<p>
6253 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
6254 <tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6255 <tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
6256 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6257<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6258declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6259declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6260declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6261declare 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]6262
6263</pre>
6264
6265<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6266declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6267declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6268declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6269declare 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]6270
6271</pre>
6272
6273<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6274declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6275declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6276declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6277declare 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]6278
6279</pre>
6280
6281<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6282declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6283declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6284declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6285declare 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]6286
6287</pre>
6288<h5>Overview:</h5>
6289<p>
6290 These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6291 the value stored in memory at <tt>ptr</tt>. It yields the original value
6292 at <tt>ptr</tt>.
6293</p>
6294<h5>Arguments:</h5>
6295<p>
6296
6297 These intrinsics take two arguments, the first a pointer to an integer value
6298 and the second an integer value. The result is also an integer value. These
6299 integer types can have any bit width, but they must all have the same bit
6300 width. The targets may only lower integer representations they support.
6301</p>
6302<h5>Semantics:</h5>
6303<p>
6304 These intrinsics does a series of operations atomically. They first load the
6305 value stored at <tt>ptr</tt>. They then do the bitwise operation
6306 <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
6307 value stored at <tt>ptr</tt>.
6308</p>
6309
6310<h5>Examples:</h5>
6311<pre>
6312%ptr = malloc i32
6313 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6314%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6315 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6316%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6317 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6318%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6319 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6320%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6321 <i>; yields {i32}:result3 = FF</i>
6322%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6323</pre>
6324</div>
6325
6326
6327<!-- _______________________________________________________________________ -->
6328<div class="doc_subsubsection">
6329 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6330 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6331 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6332 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
6333
6334</div>
6335<div class="doc_text">
6336<h5>Syntax:</h5>
6337<p>
6338 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6339 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6340 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6341 address spaces. Not all targets
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6342 support all bit widths however.</p>
6343<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6344declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6345declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6346declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6347declare 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]6348
6349</pre>
6350
6351<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6352declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6353declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6354declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6355declare 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]6356
6357</pre>
6358
6359<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6360declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6361declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6362declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6363declare 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]6364
6365</pre>
6366
6367<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6368declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6369declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6370declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6371declare 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]6372
6373</pre>
6374<h5>Overview:</h5>
6375<p>
6376 These intrinsics takes the signed or unsigned minimum or maximum of
6377 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6378 original value at <tt>ptr</tt>.
6379</p>
6380<h5>Arguments:</h5>
6381<p>
6382
6383 These intrinsics take two arguments, the first a pointer to an integer value
6384 and the second an integer value. The result is also an integer value. These
6385 integer types can have any bit width, but they must all have the same bit
6386 width. The targets may only lower integer representations they support.
6387</p>
6388<h5>Semantics:</h5>
6389<p>
6390 These intrinsics does a series of operations atomically. They first load the
6391 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
6392 <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
6393 the original value stored at <tt>ptr</tt>.
6394</p>
6395
6396<h5>Examples:</h5>
6397<pre>
6398%ptr = malloc i32
6399 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6400%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6401 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6402%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6403 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6404%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6405 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6406%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6407 <i>; yields {i32}:result3 = 8</i>
6408%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6409</pre>
6410</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6411
6412<!-- ======================================================================= -->
6413<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6414 <a name="int_general">General Intrinsics</a>
6415</div>
6416
6417<div class="doc_text">
6418<p> This class of intrinsics is designed to be generic and has
6419no specific purpose. </p>
6420</div>
6421
6422<!-- _______________________________________________________________________ -->
6423<div class="doc_subsubsection">
6424 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6425</div>
6426
6427<div class="doc_text">
6428
6429<h5>Syntax:</h5>
6430<pre>
6431 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6432</pre>
6433
6434<h5>Overview:</h5>
6435
6436<p>
6437The '<tt>llvm.var.annotation</tt>' intrinsic
6438</p>
6439
6440<h5>Arguments:</h5>
6441
6442<p>
6443The first argument is a pointer to a value, the second is a pointer to a
6444global string, the third is a pointer to a global string which is the source
6445file name, and the last argument is the line number.
6446</p>
6447
6448<h5>Semantics:</h5>
6449
6450<p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6451This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6452This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6453annotations. These have no other defined use, they are ignored by code
6454generation and optimization.
6455</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6456</div>
6457
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6458<!-- _______________________________________________________________________ -->
6459<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]6460 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6461</div>
6462
6463<div class="doc_text">
6464
6465<h5>Syntax:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6466<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6467any integer bit width.
6468</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6469<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]6470 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6471 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6472 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6473 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6474 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]6475</pre>
6476
6477<h5>Overview:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6478
6479<p>
6480The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6481</p>
6482
6483<h5>Arguments:</h5>
6484
6485<p>
6486The first argument is an integer value (result of some expression),
6487the second is a pointer to a global string, the third is a pointer to a global
6488string which is the source file name, and the last argument is the line number.
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6489It returns the value of the first argument.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6490</p>
6491
6492<h5>Semantics:</h5>
6493
6494<p>
6495This intrinsic allows annotations to be put on arbitrary expressions
6496with arbitrary strings. This can be useful for special purpose optimizations
6497that want to look for these annotations. These have no other defined use, they
6498are ignored by code generation and optimization.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6499</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6500</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6501
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6502<!-- _______________________________________________________________________ -->
6503<div class="doc_subsubsection">
6504 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6505</div>
6506
6507<div class="doc_text">
6508
6509<h5>Syntax:</h5>
6510<pre>
6511 declare void @llvm.trap()
6512</pre>
6513
6514<h5>Overview:</h5>
6515
6516<p>
6517The '<tt>llvm.trap</tt>' intrinsic
6518</p>
6519
6520<h5>Arguments:</h5>
6521
6522<p>
6523None
6524</p>
6525
6526<h5>Semantics:</h5>
6527
6528<p>
6529This intrinsics is lowered to the target dependent trap instruction. If the
6530target does not have a trap instruction, this intrinsic will be lowered to the
6531call of the abort() function.
6532</p>
6533</div>
6534
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6535<!-- _______________________________________________________________________ -->
6536<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]6537 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6538</div>
6539<div class="doc_text">
6540<h5>Syntax:</h5>
6541<pre>
6542declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
6543
6544</pre>
6545<h5>Overview:</h5>
6546<p>
6547 The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and stores
6548 it onto the stack at <tt>slot</tt>. The stack slot is adjusted to ensure that
6549 it is placed on the stack before local variables.
6550</p>
6551<h5>Arguments:</h5>
6552<p>
6553 The <tt>llvm.stackprotector</tt> intrinsic requires two pointer arguments. The
6554 first argument is the value loaded from the stack guard
6555 <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt> that
6556 has enough space to hold the value of the guard.
6557</p>
6558<h5>Semantics:</h5>
6559<p>
6560 This intrinsic causes the prologue/epilogue inserter to force the position of
6561 the <tt>AllocaInst</tt> stack slot to be before local variables on the
6562 stack. This is to ensure that if a local variable on the stack is overwritten,
6563 it will destroy the value of the guard. When the function exits, the guard on
6564 the stack is checked against the original guard. If they're different, then
6565 the program aborts by calling the <tt>__stack_chk_fail()</tt> function.
6566</p>
6567</div>
6568
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6569<!-- *********************************************************************** -->
6570<hr>
6571<address>
6572 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]6573 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6574 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]6575 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]6576
6577 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
6578 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
6579 Last modified: $Date$
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Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]6581
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