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5 <title>LLVM Assembly Language Reference Manual</title>
6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
12
13<body>
14
15<div class="doc_title"> LLVM Language Reference Manual </div>
16<ol>
17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
23 <li><a href="#linkage">Linkage Types</a></li>
24 <li><a href="#callingconv">Calling Conventions</a></li>
25 <li><a href="#globalvars">Global Variables</a></li>
26 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]27 <li><a href="#aliasstructure">Aliases</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]28 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]29 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]30 <li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]31 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
32 <li><a href="#datalayout">Data Layout</a></li>
33 </ol>
34 </li>
35 <li><a href="#typesystem">Type System</a>
36 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]37 <li><a href="#t_classifications">Type Classifications</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]38 <li><a href="#t_primitive">Primitive Types</a>
39 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]40 <li><a href="#t_floating">Floating Point Types</a></li>
41 <li><a href="#t_void">Void Type</a></li>
42 <li><a href="#t_label">Label Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]43 </ol>
44 </li>
45 <li><a href="#t_derived">Derived Types</a>
46 <ol>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]47 <li><a href="#t_integer">Integer Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]48 <li><a href="#t_array">Array Type</a></li>
49 <li><a href="#t_function">Function Type</a></li>
50 <li><a href="#t_pointer">Pointer Type</a></li>
51 <li><a href="#t_struct">Structure Type</a></li>
52 <li><a href="#t_pstruct">Packed Structure Type</a></li>
53 <li><a href="#t_vector">Vector Type</a></li>
54 <li><a href="#t_opaque">Opaque Type</a></li>
55 </ol>
56 </li>
57 </ol>
58 </li>
59 <li><a href="#constants">Constants</a>
60 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]61 <li><a href="#simpleconstants">Simple Constants</a></li>
62 <li><a href="#aggregateconstants">Aggregate Constants</a></li>
63 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
64 <li><a href="#undefvalues">Undefined Values</a></li>
65 <li><a href="#constantexprs">Constant Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]66 </ol>
67 </li>
68 <li><a href="#othervalues">Other Values</a>
69 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]70 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]71 </ol>
72 </li>
73 <li><a href="#instref">Instruction Reference</a>
74 <ol>
75 <li><a href="#terminators">Terminator Instructions</a>
76 <ol>
77 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
78 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
79 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
80 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
81 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
82 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
83 </ol>
84 </li>
85 <li><a href="#binaryops">Binary Operations</a>
86 <ol>
87 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
88 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
89 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
90 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
91 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
92 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
93 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
94 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
95 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
96 </ol>
97 </li>
98 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
99 <ol>
100 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
101 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
102 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
103 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
104 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
105 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
106 </ol>
107 </li>
108 <li><a href="#vectorops">Vector Operations</a>
109 <ol>
110 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
111 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
112 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
113 </ol>
114 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]115 <li><a href="#aggregateops">Aggregate Operations</a>
116 <ol>
117 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
118 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
119 </ol>
120 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]121 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
122 <ol>
123 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
124 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
125 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
126 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
127 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
128 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
129 </ol>
130 </li>
131 <li><a href="#convertops">Conversion Operations</a>
132 <ol>
133 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
134 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
135 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
136 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
137 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
138 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
139 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
140 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
141 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
142 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
143 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
144 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
145 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]146 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]147 <li><a href="#otherops">Other Operations</a>
148 <ol>
149 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
150 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]151 <li><a href="#i_vicmp">'<tt>vicmp</tt>' Instruction</a></li>
152 <li><a href="#i_vfcmp">'<tt>vfcmp</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]153 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
154 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
155 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
156 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
157 </ol>
158 </li>
159 </ol>
160 </li>
161 <li><a href="#intrinsics">Intrinsic Functions</a>
162 <ol>
163 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
164 <ol>
165 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
166 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
167 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
168 </ol>
169 </li>
170 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
171 <ol>
172 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
173 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
174 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
175 </ol>
176 </li>
177 <li><a href="#int_codegen">Code Generator Intrinsics</a>
178 <ol>
179 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
180 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
181 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
182 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
183 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
184 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
185 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
186 </ol>
187 </li>
188 <li><a href="#int_libc">Standard C Library Intrinsics</a>
189 <ol>
190 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
191 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
192 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
193 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
194 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]195 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
196 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
197 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]198 </ol>
199 </li>
200 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
201 <ol>
202 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
203 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
204 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
205 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
206 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
207 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
208 </ol>
209 </li>
210 <li><a href="#int_debugger">Debugger intrinsics</a></li>
211 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]212 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]213 <ol>
214 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]215 </ol>
216 </li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]217 <li><a href="#int_atomics">Atomic intrinsics</a>
218 <ol>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]219 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]220 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]221 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]222 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
223 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
224 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
225 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
226 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
227 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
228 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
229 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
230 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
231 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]232 </ol>
233 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]234 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]235 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]236 <li><a href="#int_var_annotation">
Tanya Lattner51369f32007-09-22 00:01:26 +0000[diff] [blame]237 <tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]238 <li><a href="#int_annotation">
Tanya Lattner51369f32007-09-22 00:01:26 +0000[diff] [blame]239 <tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]240 <li><a href="#int_trap">
241 <tt>llvm.trap</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]242 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]243 </li>
244 </ol>
245 </li>
246</ol>
247
248<div class="doc_author">
249 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
250 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
251</div>
252
253<!-- *********************************************************************** -->
254<div class="doc_section"> <a name="abstract">Abstract </a></div>
255<!-- *********************************************************************** -->
256
257<div class="doc_text">
258<p>This document is a reference manual for the LLVM assembly language.
Bill Wendlinge7846a52008-08-05 22:29:16 +0000[diff] [blame]259LLVM is a Static Single Assignment (SSA) based representation that provides
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]260type safety, low-level operations, flexibility, and the capability of
261representing 'all' high-level languages cleanly. It is the common code
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]262representation used throughout all phases of the LLVM compilation
263strategy.</p>
264</div>
265
266<!-- *********************************************************************** -->
267<div class="doc_section"> <a name="introduction">Introduction</a> </div>
268<!-- *********************************************************************** -->
269
270<div class="doc_text">
271
272<p>The LLVM code representation is designed to be used in three
273different forms: as an in-memory compiler IR, as an on-disk bitcode
274representation (suitable for fast loading by a Just-In-Time compiler),
275and as a human readable assembly language representation. This allows
276LLVM to provide a powerful intermediate representation for efficient
277compiler transformations and analysis, while providing a natural means
278to debug and visualize the transformations. The three different forms
279of LLVM are all equivalent. This document describes the human readable
280representation and notation.</p>
281
282<p>The LLVM representation aims to be light-weight and low-level
283while being expressive, typed, and extensible at the same time. It
284aims to be a "universal IR" of sorts, by being at a low enough level
285that high-level ideas may be cleanly mapped to it (similar to how
286microprocessors are "universal IR's", allowing many source languages to
287be mapped to them). By providing type information, LLVM can be used as
288the target of optimizations: for example, through pointer analysis, it
289can be proven that a C automatic variable is never accessed outside of
290the current function... allowing it to be promoted to a simple SSA
291value instead of a memory location.</p>
292
293</div>
294
295<!-- _______________________________________________________________________ -->
296<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
297
298<div class="doc_text">
299
300<p>It is important to note that this document describes 'well formed'
301LLVM assembly language. There is a difference between what the parser
302accepts and what is considered 'well formed'. For example, the
303following instruction is syntactically okay, but not well formed:</p>
304
305<div class="doc_code">
306<pre>
307%x = <a href="#i_add">add</a> i32 1, %x
308</pre>
309</div>
310
311<p>...because the definition of <tt>%x</tt> does not dominate all of
312its uses. The LLVM infrastructure provides a verification pass that may
313be used to verify that an LLVM module is well formed. This pass is
314automatically run by the parser after parsing input assembly and by
315the optimizer before it outputs bitcode. The violations pointed out
316by the verifier pass indicate bugs in transformation passes or input to
317the parser.</p>
318</div>
319
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]320<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]321
322<!-- *********************************************************************** -->
323<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
324<!-- *********************************************************************** -->
325
326<div class="doc_text">
327
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]328 <p>LLVM identifiers come in two basic types: global and local. Global
329 identifiers (functions, global variables) begin with the @ character. Local
330 identifiers (register names, types) begin with the % character. Additionally,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]331 there are three different formats for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]332
333<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]334 <li>Named values are represented as a string of characters with their prefix.
335 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
336 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]337 Identifiers which require other characters in their names can be surrounded
Daniel Dunbar73f9a772008-10-14 23:51:43 +0000[diff] [blame]338 with quotes. Special characters may be escaped using "\xx" where xx is the
339 ASCII code for the character in hexadecimal. In this way, any character can
340 be used in a name value, even quotes themselves.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]341
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]342 <li>Unnamed values are represented as an unsigned numeric value with their
343 prefix. For example, %12, @2, %44.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]344
345 <li>Constants, which are described in a <a href="#constants">section about
346 constants</a>, below.</li>
347</ol>
348
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]349<p>LLVM requires that values start with a prefix for two reasons: Compilers
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]350don't need to worry about name clashes with reserved words, and the set of
351reserved words may be expanded in the future without penalty. Additionally,
352unnamed identifiers allow a compiler to quickly come up with a temporary
353variable without having to avoid symbol table conflicts.</p>
354
355<p>Reserved words in LLVM are very similar to reserved words in other
356languages. There are keywords for different opcodes
357('<tt><a href="#i_add">add</a></tt>',
358 '<tt><a href="#i_bitcast">bitcast</a></tt>',
359 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
360href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
361and others. These reserved words cannot conflict with variable names, because
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]362none of them start with a prefix character ('%' or '@').</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]363
364<p>Here is an example of LLVM code to multiply the integer variable
365'<tt>%X</tt>' by 8:</p>
366
367<p>The easy way:</p>
368
369<div class="doc_code">
370<pre>
371%result = <a href="#i_mul">mul</a> i32 %X, 8
372</pre>
373</div>
374
375<p>After strength reduction:</p>
376
377<div class="doc_code">
378<pre>
379%result = <a href="#i_shl">shl</a> i32 %X, i8 3
380</pre>
381</div>
382
383<p>And the hard way:</p>
384
385<div class="doc_code">
386<pre>
387<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
388<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
389%result = <a href="#i_add">add</a> i32 %1, %1
390</pre>
391</div>
392
393<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
394important lexical features of LLVM:</p>
395
396<ol>
397
398 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
399 line.</li>
400
401 <li>Unnamed temporaries are created when the result of a computation is not
402 assigned to a named value.</li>
403
404 <li>Unnamed temporaries are numbered sequentially</li>
405
406</ol>
407
408<p>...and it also shows a convention that we follow in this document. When
409demonstrating instructions, we will follow an instruction with a comment that
410defines the type and name of value produced. Comments are shown in italic
411text.</p>
412
413</div>
414
415<!-- *********************************************************************** -->
416<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
417<!-- *********************************************************************** -->
418
419<!-- ======================================================================= -->
420<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
421</div>
422
423<div class="doc_text">
424
425<p>LLVM programs are composed of "Module"s, each of which is a
426translation unit of the input programs. Each module consists of
427functions, global variables, and symbol table entries. Modules may be
428combined together with the LLVM linker, which merges function (and
429global variable) definitions, resolves forward declarations, and merges
430symbol table entries. Here is an example of the "hello world" module:</p>
431
432<div class="doc_code">
433<pre><i>; Declare the string constant as a global constant...</i>
434<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
435 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
436
437<i>; External declaration of the puts function</i>
438<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
439
440<i>; Definition of main function</i>
441define i32 @main() { <i>; i32()* </i>
442 <i>; Convert [13x i8 ]* to i8 *...</i>
443 %cast210 = <a
444 href="#i_getelementptr">getelementptr</a> [13 x i8 ]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
445
446 <i>; Call puts function to write out the string to stdout...</i>
447 <a
448 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
449 <a
450 href="#i_ret">ret</a> i32 0<br>}<br>
451</pre>
452</div>
453
454<p>This example is made up of a <a href="#globalvars">global variable</a>
455named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
456function, and a <a href="#functionstructure">function definition</a>
457for "<tt>main</tt>".</p>
458
459<p>In general, a module is made up of a list of global values,
460where both functions and global variables are global values. Global values are
461represented by a pointer to a memory location (in this case, a pointer to an
462array of char, and a pointer to a function), and have one of the following <a
463href="#linkage">linkage types</a>.</p>
464
465</div>
466
467<!-- ======================================================================= -->
468<div class="doc_subsection">
469 <a name="linkage">Linkage Types</a>
470</div>
471
472<div class="doc_text">
473
474<p>
475All Global Variables and Functions have one of the following types of linkage:
476</p>
477
478<dl>
479
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]480 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]481
482 <dd>Global values with internal linkage are only directly accessible by
483 objects in the current module. In particular, linking code into a module with
484 an internal global value may cause the internal to be renamed as necessary to
485 avoid collisions. Because the symbol is internal to the module, all
486 references can be updated. This corresponds to the notion of the
487 '<tt>static</tt>' keyword in C.
488 </dd>
489
490 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
491
492 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
493 the same name when linkage occurs. This is typically used to implement
494 inline functions, templates, or other code which must be generated in each
495 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
496 allowed to be discarded.
497 </dd>
498
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]499 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
500
501 <dd>"<tt>common</tt>" linkage is exactly the same as <tt>linkonce</tt>
502 linkage, except that unreferenced <tt>common</tt> globals may not be
503 discarded. This is used for globals that may be emitted in multiple
504 translation units, but that are not guaranteed to be emitted into every
505 translation unit that uses them. One example of this is tentative
506 definitions in C, such as "<tt>int X;</tt>" at global scope.
507 </dd>
508
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]509 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
510
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]511 <dd>"<tt>weak</tt>" linkage is the same as <tt>common</tt> linkage, except
512 that some targets may choose to emit different assembly sequences for them
513 for target-dependent reasons. This is used for globals that are declared
514 "weak" in C source code.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]515 </dd>
516
517 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
518
519 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
520 pointer to array type. When two global variables with appending linkage are
521 linked together, the two global arrays are appended together. This is the
522 LLVM, typesafe, equivalent of having the system linker append together
523 "sections" with identical names when .o files are linked.
524 </dd>
525
526 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]527 <dd>The semantics of this linkage follow the ELF object file model: the
528 symbol is weak until linked, if not linked, the symbol becomes null instead
529 of being an undefined reference.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]530 </dd>
531
532 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
533
534 <dd>If none of the above identifiers are used, the global is externally
535 visible, meaning that it participates in linkage and can be used to resolve
536 external symbol references.
537 </dd>
538</dl>
539
540 <p>
541 The next two types of linkage are targeted for Microsoft Windows platform
542 only. They are designed to support importing (exporting) symbols from (to)
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]543 DLLs (Dynamic Link Libraries).
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]544 </p>
545
546 <dl>
547 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
548
549 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
550 or variable via a global pointer to a pointer that is set up by the DLL
551 exporting the symbol. On Microsoft Windows targets, the pointer name is
552 formed by combining <code>_imp__</code> and the function or variable name.
553 </dd>
554
555 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
556
557 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
558 pointer to a pointer in a DLL, so that it can be referenced with the
559 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
560 name is formed by combining <code>_imp__</code> and the function or variable
561 name.
562 </dd>
563
564</dl>
565
566<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
567variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
568variable and was linked with this one, one of the two would be renamed,
569preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
570external (i.e., lacking any linkage declarations), they are accessible
571outside of the current module.</p>
572<p>It is illegal for a function <i>declaration</i>
573to have any linkage type other than "externally visible", <tt>dllimport</tt>,
574or <tt>extern_weak</tt>.</p>
575<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]576linkages.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]577</div>
578
579<!-- ======================================================================= -->
580<div class="doc_subsection">
581 <a name="callingconv">Calling Conventions</a>
582</div>
583
584<div class="doc_text">
585
586<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
587and <a href="#i_invoke">invokes</a> can all have an optional calling convention
588specified for the call. The calling convention of any pair of dynamic
589caller/callee must match, or the behavior of the program is undefined. The
590following calling conventions are supported by LLVM, and more may be added in
591the future:</p>
592
593<dl>
594 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
595
596 <dd>This calling convention (the default if no other calling convention is
597 specified) matches the target C calling conventions. This calling convention
598 supports varargs function calls and tolerates some mismatch in the declared
599 prototype and implemented declaration of the function (as does normal C).
600 </dd>
601
602 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
603
604 <dd>This calling convention attempts to make calls as fast as possible
605 (e.g. by passing things in registers). This calling convention allows the
606 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]607 without having to conform to an externally specified ABI (Application Binary
608 Interface). Implementations of this convention should allow arbitrary
Arnold Schwaighofer07444922008-05-14 09:17:12 +0000[diff] [blame]609 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> to be
610 supported. This calling convention does not support varargs and requires the
611 prototype of all callees to exactly match the prototype of the function
612 definition.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]613 </dd>
614
615 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
616
617 <dd>This calling convention attempts to make code in the caller as efficient
618 as possible under the assumption that the call is not commonly executed. As
619 such, these calls often preserve all registers so that the call does not break
620 any live ranges in the caller side. This calling convention does not support
621 varargs and requires the prototype of all callees to exactly match the
622 prototype of the function definition.
623 </dd>
624
625 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
626
627 <dd>Any calling convention may be specified by number, allowing
628 target-specific calling conventions to be used. Target specific calling
629 conventions start at 64.
630 </dd>
631</dl>
632
633<p>More calling conventions can be added/defined on an as-needed basis, to
634support pascal conventions or any other well-known target-independent
635convention.</p>
636
637</div>
638
639<!-- ======================================================================= -->
640<div class="doc_subsection">
641 <a name="visibility">Visibility Styles</a>
642</div>
643
644<div class="doc_text">
645
646<p>
647All Global Variables and Functions have one of the following visibility styles:
648</p>
649
650<dl>
651 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
652
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]653 <dd>On targets that use the ELF object file format, default visibility means
654 that the declaration is visible to other
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]655 modules and, in shared libraries, means that the declared entity may be
656 overridden. On Darwin, default visibility means that the declaration is
657 visible to other modules. Default visibility corresponds to "external
658 linkage" in the language.
659 </dd>
660
661 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
662
663 <dd>Two declarations of an object with hidden visibility refer to the same
664 object if they are in the same shared object. Usually, hidden visibility
665 indicates that the symbol will not be placed into the dynamic symbol table,
666 so no other module (executable or shared library) can reference it
667 directly.
668 </dd>
669
670 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
671
672 <dd>On ELF, protected visibility indicates that the symbol will be placed in
673 the dynamic symbol table, but that references within the defining module will
674 bind to the local symbol. That is, the symbol cannot be overridden by another
675 module.
676 </dd>
677</dl>
678
679</div>
680
681<!-- ======================================================================= -->
682<div class="doc_subsection">
683 <a name="globalvars">Global Variables</a>
684</div>
685
686<div class="doc_text">
687
688<p>Global variables define regions of memory allocated at compilation time
689instead of run-time. Global variables may optionally be initialized, may have
690an explicit section to be placed in, and may have an optional explicit alignment
691specified. A variable may be defined as "thread_local", which means that it
692will not be shared by threads (each thread will have a separated copy of the
693variable). A variable may be defined as a global "constant," which indicates
694that the contents of the variable will <b>never</b> be modified (enabling better
695optimization, allowing the global data to be placed in the read-only section of
696an executable, etc). Note that variables that need runtime initialization
697cannot be marked "constant" as there is a store to the variable.</p>
698
699<p>
700LLVM explicitly allows <em>declarations</em> of global variables to be marked
701constant, even if the final definition of the global is not. This capability
702can be used to enable slightly better optimization of the program, but requires
703the language definition to guarantee that optimizations based on the
704'constantness' are valid for the translation units that do not include the
705definition.
706</p>
707
708<p>As SSA values, global variables define pointer values that are in
709scope (i.e. they dominate) all basic blocks in the program. Global
710variables always define a pointer to their "content" type because they
711describe a region of memory, and all memory objects in LLVM are
712accessed through pointers.</p>
713
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]714<p>A global variable may be declared to reside in a target-specifc numbered
715address space. For targets that support them, address spaces may affect how
716optimizations are performed and/or what target instructions are used to access
Christopher Lamb20a39e92007-12-12 08:44:39 +0000[diff] [blame]717the variable. The default address space is zero. The address space qualifier
718must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]719
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]720<p>LLVM allows an explicit section to be specified for globals. If the target
721supports it, it will emit globals to the section specified.</p>
722
723<p>An explicit alignment may be specified for a global. If not present, or if
724the alignment is set to zero, the alignment of the global is set by the target
725to whatever it feels convenient. If an explicit alignment is specified, the
726global is forced to have at least that much alignment. All alignments must be
727a power of 2.</p>
728
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]729<p>For example, the following defines a global in a numbered address space with
730an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]731
732<div class="doc_code">
733<pre>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]734@G = constant float 1.0 addrspace(5), section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]735</pre>
736</div>
737
738</div>
739
740
741<!-- ======================================================================= -->
742<div class="doc_subsection">
743 <a name="functionstructure">Functions</a>
744</div>
745
746<div class="doc_text">
747
748<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
749an optional <a href="#linkage">linkage type</a>, an optional
750<a href="#visibility">visibility style</a>, an optional
751<a href="#callingconv">calling convention</a>, a return type, an optional
752<a href="#paramattrs">parameter attribute</a> for the return type, a function
753name, a (possibly empty) argument list (each with optional
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]754<a href="#paramattrs">parameter attributes</a>), optional
755<a href="#fnattrs">function attributes</a>, an optional section,
756an optional alignment, an optional <a href="#gc">garbage collector name</a>,
Chris Lattneree202542008-10-04 18:10:21 +0000[diff] [blame]757an opening curly brace, a list of basic blocks, and a closing curly brace.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]758
759LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
760optional <a href="#linkage">linkage type</a>, an optional
761<a href="#visibility">visibility style</a>, an optional
762<a href="#callingconv">calling convention</a>, a return type, an optional
763<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]764name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksend606f5b2007-12-10 03:30:21 +0000[diff] [blame]765<a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]766
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]767<p>A function definition contains a list of basic blocks, forming the CFG
768(Control Flow Graph) for
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]769the function. Each basic block may optionally start with a label (giving the
770basic block a symbol table entry), contains a list of instructions, and ends
771with a <a href="#terminators">terminator</a> instruction (such as a branch or
772function return).</p>
773
774<p>The first basic block in a function is special in two ways: it is immediately
775executed on entrance to the function, and it is not allowed to have predecessor
776basic blocks (i.e. there can not be any branches to the entry block of a
777function). Because the block can have no predecessors, it also cannot have any
778<a href="#i_phi">PHI nodes</a>.</p>
779
780<p>LLVM allows an explicit section to be specified for functions. If the target
781supports it, it will emit functions to the section specified.</p>
782
783<p>An explicit alignment may be specified for a function. If not present, or if
784the alignment is set to zero, the alignment of the function is set by the target
785to whatever it feels convenient. If an explicit alignment is specified, the
786function is forced to have at least that much alignment. All alignments must be
787a power of 2.</p>
788
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]789 <h5>Syntax:</h5>
790
791<div class="doc_code">
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]792<tt>
793define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
794 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
795 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
796 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
797 [<a href="#gc">gc</a>] { ... }
798</tt>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]799</div>
800
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]801</div>
802
803
804<!-- ======================================================================= -->
805<div class="doc_subsection">
806 <a name="aliasstructure">Aliases</a>
807</div>
808<div class="doc_text">
809 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikov96822812008-03-22 08:36:14 +0000[diff] [blame]810 function, global variable, another alias or bitcast of global value). Aliases
811 may have an optional <a href="#linkage">linkage type</a>, and an
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]812 optional <a href="#visibility">visibility style</a>.</p>
813
814 <h5>Syntax:</h5>
815
816<div class="doc_code">
817<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]818@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]819</pre>
820</div>
821
822</div>
823
824
825
826<!-- ======================================================================= -->
827<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
828<div class="doc_text">
829 <p>The return type and each parameter of a function type may have a set of
830 <i>parameter attributes</i> associated with them. Parameter attributes are
831 used to communicate additional information about the result or parameters of
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]832 a function. Parameter attributes are considered to be part of the function,
833 not of the function type, so functions with different parameter attributes
834 can have the same function type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]835
836 <p>Parameter attributes are simple keywords that follow the type specified. If
837 multiple parameter attributes are needed, they are space separated. For
838 example:</p>
839
840<div class="doc_code">
841<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]842declare i32 @printf(i8* noalias , ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]843declare i32 @atoi(i8 zeroext)
844declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]845</pre>
846</div>
847
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]848 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
849 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]850
851 <p>Currently, only the following parameter attributes are defined:</p>
852 <dl>
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]853 <dt><tt>zeroext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]854 <dd>This indicates to the code generator that the parameter or return value
855 should be zero-extended to a 32-bit value by the caller (for a parameter)
856 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]857
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]858 <dt><tt>signext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]859 <dd>This indicates to the code generator that the parameter or return value
860 should be sign-extended to a 32-bit value by the caller (for a parameter)
861 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]862
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]863 <dt><tt>inreg</tt></dt>
Dale Johannesenc08a0e22008-09-25 20:47:45 +0000[diff] [blame]864 <dd>This indicates that this parameter or return value should be treated
865 in a special target-dependent fashion during while emitting code for a
866 function call or return (usually, by putting it in a register as opposed
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]867 to memory, though some targets use it to distinguish between two different
868 kinds of registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]869
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]870 <dt><tt><a name="byval">byval</a></tt></dt>
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]871 <dd>This indicates that the pointer parameter should really be passed by
872 value to the function. The attribute implies that a hidden copy of the
873 pointee is made between the caller and the callee, so the callee is unable
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]874 to modify the value in the callee. This attribute is only valid on LLVM
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]875 pointer arguments. It is generally used to pass structs and arrays by
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]876 value, but is also valid on pointers to scalars. The copy is considered to
877 belong to the caller not the callee (for example,
878 <tt><a href="#readonly">readonly</a></tt> functions should not write to
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]879 <tt>byval</tt> parameters). This is not a valid attribute for return
880 values. </dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]881
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]882 <dt><tt>sret</tt></dt>
Duncan Sands616cc032008-02-18 04:19:38 +0000[diff] [blame]883 <dd>This indicates that the pointer parameter specifies the address of a
884 structure that is the return value of the function in the source program.
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]885 This pointer must be guaranteed by the caller to be valid: loads and stores
886 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]887 be applied to the first parameter. This is not a valid attribute for
888 return values. </dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]889
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]890 <dt><tt>noalias</tt></dt>
Owen Andersonc4fc4cd2008-02-18 04:09:01 +0000[diff] [blame]891 <dd>This indicates that the parameter does not alias any global or any other
892 parameter. The caller is responsible for ensuring that this is the case,
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]893 usually by placing the value in a stack allocation. This is not a valid
894 attribute for return values.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]895
Duncan Sands4ee46812007-07-27 19:57:41 +0000[diff] [blame]896 <dt><tt>nest</tt></dt>
Duncan Sandsf1a7d4c2008-07-08 09:27:25 +0000[diff] [blame]897 <dd>This indicates that the pointer parameter can be excised using the
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]898 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
899 attribute for return values.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]900 </dl>
901
902</div>
903
904<!-- ======================================================================= -->
905<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]906 <a name="gc">Garbage Collector Names</a>
907</div>
908
909<div class="doc_text">
910<p>Each function may specify a garbage collector name, which is simply a
911string.</p>
912
913<div class="doc_code"><pre
914>define void @f() gc "name" { ...</pre></div>
915
916<p>The compiler declares the supported values of <i>name</i>. Specifying a
917collector which will cause the compiler to alter its output in order to support
918the named garbage collection algorithm.</p>
919</div>
920
921<!-- ======================================================================= -->
922<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]923 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]924</div>
925
926<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]927
928<p>Function attributes are set to communicate additional information about
929 a function. Function attributes are considered to be part of the function,
930 not of the function type, so functions with different parameter attributes
931 can have the same function type.</p>
932
933 <p>Function attributes are simple keywords that follow the type specified. If
934 multiple attributes are needed, they are space separated. For
935 example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]936
937<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]938<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]939define void @f() noinline { ... }
940define void @f() alwaysinline { ... }
941define void @f() alwaysinline optsize { ... }
942define void @f() optsize
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]943</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]944</div>
945
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]946<dl>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]947<dt><tt>alwaysinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]948<dd>This attribute indicates that the inliner should attempt to inline this
949function into callers whenever possible, ignoring any active inlining size
950threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]951
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]952<dt><tt>noinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]953<dd>This attribute indicates that the inliner should never inline this function
Chris Lattner377f3ae2008-10-05 17:14:59 +0000[diff] [blame]954in any situation. This attribute may not be used together with the
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]955<tt>alwaysinline</tt> attribute.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]956
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]957<dt><tt>optsize</tt></dt>
Devang Patelc29099b2008-09-29 18:34:44 +0000[diff] [blame]958<dd>This attribute suggests that optimization passes and code generator passes
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]959make choices that keep the code size of this function low, and otherwise do
960optimizations specifically to reduce code size.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]961
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]962<dt><tt>noreturn</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]963<dd>This function attribute indicates that the function never returns normally.
964This produces undefined behavior at runtime if the function ever does
965dynamically return.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]966
967<dt><tt>nounwind</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]968<dd>This function attribute indicates that the function never returns with an
969unwind or exceptional control flow. If the function does unwind, its runtime
970behavior is undefined.</dd>
971
972<dt><tt>readnone</tt></dt>
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]973<dd>This attribute indicates that the function computes its result (or the
974exception it throws) based strictly on its arguments, without dereferencing any
975pointer arguments or otherwise accessing any mutable state (e.g. memory, control
976registers, etc) visible to caller functions. It does not write through any
977pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments) and
978never changes any state visible to callers.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]979
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]980<dt><tt><a name="readonly">readonly</a></tt></dt>
981<dd>This attribute indicates that the function does not write through any
982pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments)
983or otherwise modify any state (e.g. memory, control registers, etc) visible to
984caller functions. It may dereference pointer arguments and read state that may
985be set in the caller. A readonly function always returns the same value (or
986throws the same exception) when called with the same set of arguments and global
987state.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]988</dl>
989
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]990</div>
991
992<!-- ======================================================================= -->
993<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]994 <a name="moduleasm">Module-Level Inline Assembly</a>
995</div>
996
997<div class="doc_text">
998<p>
999Modules may contain "module-level inline asm" blocks, which corresponds to the
1000GCC "file scope inline asm" blocks. These blocks are internally concatenated by
1001LLVM and treated as a single unit, but may be separated in the .ll file if
1002desired. The syntax is very simple:
1003</p>
1004
1005<div class="doc_code">
1006<pre>
1007module asm "inline asm code goes here"
1008module asm "more can go here"
1009</pre>
1010</div>
1011
1012<p>The strings can contain any character by escaping non-printable characters.
1013 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
1014 for the number.
1015</p>
1016
1017<p>
1018 The inline asm code is simply printed to the machine code .s file when
1019 assembly code is generated.
1020</p>
1021</div>
1022
1023<!-- ======================================================================= -->
1024<div class="doc_subsection">
1025 <a name="datalayout">Data Layout</a>
1026</div>
1027
1028<div class="doc_text">
1029<p>A module may specify a target specific data layout string that specifies how
1030data is to be laid out in memory. The syntax for the data layout is simply:</p>
1031<pre> target datalayout = "<i>layout specification</i>"</pre>
1032<p>The <i>layout specification</i> consists of a list of specifications
1033separated by the minus sign character ('-'). Each specification starts with a
1034letter and may include other information after the letter to define some
1035aspect of the data layout. The specifications accepted are as follows: </p>
1036<dl>
1037 <dt><tt>E</tt></dt>
1038 <dd>Specifies that the target lays out data in big-endian form. That is, the
1039 bits with the most significance have the lowest address location.</dd>
1040 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1041 <dd>Specifies that the target lays out data in little-endian form. That is,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1042 the bits with the least significance have the lowest address location.</dd>
1043 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1044 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
1045 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
1046 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
1047 too.</dd>
1048 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1049 <dd>This specifies the alignment for an integer type of a given bit
1050 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1051 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1052 <dd>This specifies the alignment for a vector type of a given bit
1053 <i>size</i>.</dd>
1054 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1055 <dd>This specifies the alignment for a floating point type of a given bit
1056 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1057 (double).</dd>
1058 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1059 <dd>This specifies the alignment for an aggregate type of a given bit
1060 <i>size</i>.</dd>
1061</dl>
1062<p>When constructing the data layout for a given target, LLVM starts with a
1063default set of specifications which are then (possibly) overriden by the
1064specifications in the <tt>datalayout</tt> keyword. The default specifications
1065are given in this list:</p>
1066<ul>
1067 <li><tt>E</tt> - big endian</li>
1068 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1069 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1070 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1071 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1072 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1073 <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]1074 alignment of 64-bits</li>
1075 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1076 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1077 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1078 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1079 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
1080</ul>
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]1081<p>When LLVM is determining the alignment for a given type, it uses the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1082following rules:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1083<ol>
1084 <li>If the type sought is an exact match for one of the specifications, that
1085 specification is used.</li>
1086 <li>If no match is found, and the type sought is an integer type, then the
1087 smallest integer type that is larger than the bitwidth of the sought type is
1088 used. If none of the specifications are larger than the bitwidth then the the
1089 largest integer type is used. For example, given the default specifications
1090 above, the i7 type will use the alignment of i8 (next largest) while both
1091 i65 and i256 will use the alignment of i64 (largest specified).</li>
1092 <li>If no match is found, and the type sought is a vector type, then the
1093 largest vector type that is smaller than the sought vector type will be used
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1094 as a fall back. This happens because &lt;128 x double&gt; can be implemented
1095 in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1096</ol>
1097</div>
1098
1099<!-- *********************************************************************** -->
1100<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1101<!-- *********************************************************************** -->
1102
1103<div class="doc_text">
1104
1105<p>The LLVM type system is one of the most important features of the
1106intermediate representation. Being typed enables a number of
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1107optimizations to be performed on the intermediate representation directly,
1108without having to do
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1109extra analyses on the side before the transformation. A strong type
1110system makes it easier to read the generated code and enables novel
1111analyses and transformations that are not feasible to perform on normal
1112three address code representations.</p>
1113
1114</div>
1115
1116<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1117<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1118Classifications</a> </div>
1119<div class="doc_text">
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1120<p>The types fall into a few useful
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1121classifications:</p>
1122
1123<table border="1" cellspacing="0" cellpadding="4">
1124 <tbody>
1125 <tr><th>Classification</th><th>Types</th></tr>
1126 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1127 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1128 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1129 </tr>
1130 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1131 <td><a href="#t_floating">floating point</a></td>
1132 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1133 </tr>
1134 <tr>
1135 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1136 <td><a href="#t_integer">integer</a>,
1137 <a href="#t_floating">floating point</a>,
1138 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1139 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1140 <a href="#t_struct">structure</a>,
1141 <a href="#t_array">array</a>,
Dan Gohmand13951e2008-05-23 22:50:26 +0000[diff] [blame]1142 <a href="#t_label">label</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1143 </td>
1144 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1145 <tr>
1146 <td><a href="#t_primitive">primitive</a></td>
1147 <td><a href="#t_label">label</a>,
1148 <a href="#t_void">void</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1149 <a href="#t_floating">floating point</a>.</td>
1150 </tr>
1151 <tr>
1152 <td><a href="#t_derived">derived</a></td>
1153 <td><a href="#t_integer">integer</a>,
1154 <a href="#t_array">array</a>,
1155 <a href="#t_function">function</a>,
1156 <a href="#t_pointer">pointer</a>,
1157 <a href="#t_struct">structure</a>,
1158 <a href="#t_pstruct">packed structure</a>,
1159 <a href="#t_vector">vector</a>,
1160 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1161 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1162 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1163 </tbody>
1164</table>
1165
1166<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1167most important. Values of these types are the only ones which can be
1168produced by instructions, passed as arguments, or used as operands to
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]1169instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1170</div>
1171
1172<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1173<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1174
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1175<div class="doc_text">
1176<p>The primitive types are the fundamental building blocks of the LLVM
1177system.</p>
1178
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1179</div>
1180
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1181<!-- _______________________________________________________________________ -->
1182<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1183
1184<div class="doc_text">
1185 <table>
1186 <tbody>
1187 <tr><th>Type</th><th>Description</th></tr>
1188 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1189 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1190 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1191 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1192 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1193 </tbody>
1194 </table>
1195</div>
1196
1197<!-- _______________________________________________________________________ -->
1198<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1199
1200<div class="doc_text">
1201<h5>Overview:</h5>
1202<p>The void type does not represent any value and has no size.</p>
1203
1204<h5>Syntax:</h5>
1205
1206<pre>
1207 void
1208</pre>
1209</div>
1210
1211<!-- _______________________________________________________________________ -->
1212<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1213
1214<div class="doc_text">
1215<h5>Overview:</h5>
1216<p>The label type represents code labels.</p>
1217
1218<h5>Syntax:</h5>
1219
1220<pre>
1221 label
1222</pre>
1223</div>
1224
1225
1226<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1227<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1228
1229<div class="doc_text">
1230
1231<p>The real power in LLVM comes from the derived types in the system.
1232This is what allows a programmer to represent arrays, functions,
1233pointers, and other useful types. Note that these derived types may be
1234recursive: For example, it is possible to have a two dimensional array.</p>
1235
1236</div>
1237
1238<!-- _______________________________________________________________________ -->
1239<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1240
1241<div class="doc_text">
1242
1243<h5>Overview:</h5>
1244<p>The integer type is a very simple derived type that simply specifies an
1245arbitrary bit width for the integer type desired. Any bit width from 1 bit to
12462^23-1 (about 8 million) can be specified.</p>
1247
1248<h5>Syntax:</h5>
1249
1250<pre>
1251 iN
1252</pre>
1253
1254<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1255value.</p>
1256
1257<h5>Examples:</h5>
1258<table class="layout">
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1259 <tbody>
1260 <tr>
1261 <td><tt>i1</tt></td>
1262 <td>a single-bit integer.</td>
1263 </tr><tr>
1264 <td><tt>i32</tt></td>
1265 <td>a 32-bit integer.</td>
1266 </tr><tr>
1267 <td><tt>i1942652</tt></td>
1268 <td>a really big integer of over 1 million bits.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1269 </tr>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1270 </tbody>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1271</table>
1272</div>
1273
1274<!-- _______________________________________________________________________ -->
1275<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1276
1277<div class="doc_text">
1278
1279<h5>Overview:</h5>
1280
1281<p>The array type is a very simple derived type that arranges elements
1282sequentially in memory. The array type requires a size (number of
1283elements) and an underlying data type.</p>
1284
1285<h5>Syntax:</h5>
1286
1287<pre>
1288 [&lt;# elements&gt; x &lt;elementtype&gt;]
1289</pre>
1290
1291<p>The number of elements is a constant integer value; elementtype may
1292be any type with a size.</p>
1293
1294<h5>Examples:</h5>
1295<table class="layout">
1296 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1297 <td class="left"><tt>[40 x i32]</tt></td>
1298 <td class="left">Array of 40 32-bit integer values.</td>
1299 </tr>
1300 <tr class="layout">
1301 <td class="left"><tt>[41 x i32]</tt></td>
1302 <td class="left">Array of 41 32-bit integer values.</td>
1303 </tr>
1304 <tr class="layout">
1305 <td class="left"><tt>[4 x i8]</tt></td>
1306 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1307 </tr>
1308</table>
1309<p>Here are some examples of multidimensional arrays:</p>
1310<table class="layout">
1311 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1312 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1313 <td class="left">3x4 array of 32-bit integer values.</td>
1314 </tr>
1315 <tr class="layout">
1316 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1317 <td class="left">12x10 array of single precision floating point values.</td>
1318 </tr>
1319 <tr class="layout">
1320 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1321 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1322 </tr>
1323</table>
1324
1325<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1326length array. Normally, accesses past the end of an array are undefined in
1327LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1328As a special case, however, zero length arrays are recognized to be variable
1329length. This allows implementation of 'pascal style arrays' with the LLVM
1330type "{ i32, [0 x float]}", for example.</p>
1331
1332</div>
1333
1334<!-- _______________________________________________________________________ -->
1335<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
1336<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1337
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1338<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1339
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1340<p>The function type can be thought of as a function signature. It
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1341consists of a return type and a list of formal parameter types. The
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1342return 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]1343If 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]1344class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1345
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1346<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1347
1348<pre>
1349 &lt;returntype list&gt; (&lt;parameter list&gt;)
1350</pre>
1351
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1352<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
1353specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1354which indicates that the function takes a variable number of arguments.
1355Variable argument functions can access their arguments with the <a
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1356 href="#int_varargs">variable argument handling intrinsic</a> functions.
1357'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1358<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1359
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1360<h5>Examples:</h5>
1361<table class="layout">
1362 <tr class="layout">
1363 <td class="left"><tt>i32 (i32)</tt></td>
1364 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1365 </td>
1366 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1367 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1368 </tt></td>
1369 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1370 an <tt>i16</tt> that should be sign extended and a
1371 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1372 <tt>float</tt>.
1373 </td>
1374 </tr><tr class="layout">
1375 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1376 <td class="left">A vararg function that takes at least one
1377 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1378 which returns an integer. This is the signature for <tt>printf</tt> in
1379 LLVM.
1380 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1381 </tr><tr class="layout">
1382 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Devang Patel6dddba22008-03-24 18:10:52 +0000[diff] [blame]1383 <td class="left">A function taking an <tt>i32></tt>, returning two
1384 <tt> i32 </tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1385 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1386 </tr>
1387</table>
1388
1389</div>
1390<!-- _______________________________________________________________________ -->
1391<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
1392<div class="doc_text">
1393<h5>Overview:</h5>
1394<p>The structure type is used to represent a collection of data members
1395together in memory. The packing of the field types is defined to match
1396the ABI of the underlying processor. The elements of a structure may
1397be any type that has a size.</p>
1398<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1399and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1400field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1401instruction.</p>
1402<h5>Syntax:</h5>
1403<pre> { &lt;type list&gt; }<br></pre>
1404<h5>Examples:</h5>
1405<table class="layout">
1406 <tr class="layout">
1407 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1408 <td class="left">A triple of three <tt>i32</tt> values</td>
1409 </tr><tr class="layout">
1410 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1411 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1412 second element is a <a href="#t_pointer">pointer</a> to a
1413 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1414 an <tt>i32</tt>.</td>
1415 </tr>
1416</table>
1417</div>
1418
1419<!-- _______________________________________________________________________ -->
1420<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1421</div>
1422<div class="doc_text">
1423<h5>Overview:</h5>
1424<p>The packed structure type is used to represent a collection of data members
1425together in memory. There is no padding between fields. Further, the alignment
1426of a packed structure is 1 byte. The elements of a packed structure may
1427be any type that has a size.</p>
1428<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1429and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1430field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1431instruction.</p>
1432<h5>Syntax:</h5>
1433<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1434<h5>Examples:</h5>
1435<table class="layout">
1436 <tr class="layout">
1437 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1438 <td class="left">A triple of three <tt>i32</tt> values</td>
1439 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1440 <td class="left">
1441<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1442 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1443 second element is a <a href="#t_pointer">pointer</a> to a
1444 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1445 an <tt>i32</tt>.</td>
1446 </tr>
1447</table>
1448</div>
1449
1450<!-- _______________________________________________________________________ -->
1451<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
1452<div class="doc_text">
1453<h5>Overview:</h5>
1454<p>As in many languages, the pointer type represents a pointer or
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]1455reference to another object, which must live in memory. Pointer types may have
1456an optional address space attribute defining the target-specific numbered
1457address space where the pointed-to object resides. The default address space is
1458zero.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1459<h5>Syntax:</h5>
1460<pre> &lt;type&gt; *<br></pre>
1461<h5>Examples:</h5>
1462<table class="layout">
1463 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1464 <td class="left"><tt>[4x i32]*</tt></td>
1465 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1466 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1467 </tr>
1468 <tr class="layout">
1469 <td class="left"><tt>i32 (i32 *) *</tt></td>
1470 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1471 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1472 <tt>i32</tt>.</td>
1473 </tr>
1474 <tr class="layout">
1475 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1476 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1477 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1478 </tr>
1479</table>
1480</div>
1481
1482<!-- _______________________________________________________________________ -->
1483<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
1484<div class="doc_text">
1485
1486<h5>Overview:</h5>
1487
1488<p>A vector type is a simple derived type that represents a vector
1489of elements. Vector types are used when multiple primitive data
1490are operated in parallel using a single instruction (SIMD).
1491A vector type requires a size (number of
1492elements) and an underlying primitive data type. Vectors must have a power
1493of two length (1, 2, 4, 8, 16 ...). Vector types are
1494considered <a href="#t_firstclass">first class</a>.</p>
1495
1496<h5>Syntax:</h5>
1497
1498<pre>
1499 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1500</pre>
1501
1502<p>The number of elements is a constant integer value; elementtype may
1503be any integer or floating point type.</p>
1504
1505<h5>Examples:</h5>
1506
1507<table class="layout">
1508 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1509 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1510 <td class="left">Vector of 4 32-bit integer values.</td>
1511 </tr>
1512 <tr class="layout">
1513 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1514 <td class="left">Vector of 8 32-bit floating-point values.</td>
1515 </tr>
1516 <tr class="layout">
1517 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1518 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1519 </tr>
1520</table>
1521</div>
1522
1523<!-- _______________________________________________________________________ -->
1524<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1525<div class="doc_text">
1526
1527<h5>Overview:</h5>
1528
1529<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksenda0706e2007-10-14 00:34:53 +0000[diff] [blame]1530corresponds (for example) to the C notion of a forward declared structure type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1531In LLVM, opaque types can eventually be resolved to any type (not just a
1532structure type).</p>
1533
1534<h5>Syntax:</h5>
1535
1536<pre>
1537 opaque
1538</pre>
1539
1540<h5>Examples:</h5>
1541
1542<table class="layout">
1543 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1544 <td class="left"><tt>opaque</tt></td>
1545 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1546 </tr>
1547</table>
1548</div>
1549
1550
1551<!-- *********************************************************************** -->
1552<div class="doc_section"> <a name="constants">Constants</a> </div>
1553<!-- *********************************************************************** -->
1554
1555<div class="doc_text">
1556
1557<p>LLVM has several different basic types of constants. This section describes
1558them all and their syntax.</p>
1559
1560</div>
1561
1562<!-- ======================================================================= -->
1563<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1564
1565<div class="doc_text">
1566
1567<dl>
1568 <dt><b>Boolean constants</b></dt>
1569
1570 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1571 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
1572 </dd>
1573
1574 <dt><b>Integer constants</b></dt>
1575
1576 <dd>Standard integers (such as '4') are constants of the <a
1577 href="#t_integer">integer</a> type. Negative numbers may be used with
1578 integer types.
1579 </dd>
1580
1581 <dt><b>Floating point constants</b></dt>
1582
1583 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1584 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]1585 notation (see below). The assembler requires the exact decimal value of
1586 a floating-point constant. For example, the assembler accepts 1.25 but
1587 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1588 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1589
1590 <dt><b>Null pointer constants</b></dt>
1591
1592 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
1593 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1594
1595</dl>
1596
1597<p>The one non-intuitive notation for constants is the optional hexadecimal form
1598of floating point constants. For example, the form '<tt>double
15990x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
16004.5e+15</tt>'. The only time hexadecimal floating point constants are required
1601(and the only time that they are generated by the disassembler) is when a
1602floating point constant must be emitted but it cannot be represented as a
1603decimal floating point number. For example, NaN's, infinities, and other
1604special values are represented in their IEEE hexadecimal format so that
1605assembly and disassembly do not cause any bits to change in the constants.</p>
1606
1607</div>
1608
1609<!-- ======================================================================= -->
1610<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1611</div>
1612
1613<div class="doc_text">
1614<p>Aggregate constants arise from aggregation of simple constants
1615and smaller aggregate constants.</p>
1616
1617<dl>
1618 <dt><b>Structure constants</b></dt>
1619
1620 <dd>Structure constants are represented with notation similar to structure
1621 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner6c8de962007-12-25 20:34:52 +0000[diff] [blame]1622 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1623 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]1624 must have <a href="#t_struct">structure type</a>, and the number and
1625 types of elements must match those specified by the type.
1626 </dd>
1627
1628 <dt><b>Array constants</b></dt>
1629
1630 <dd>Array constants are represented with notation similar to array type
1631 definitions (a comma separated list of elements, surrounded by square brackets
1632 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
1633 constants must have <a href="#t_array">array type</a>, and the number and
1634 types of elements must match those specified by the type.
1635 </dd>
1636
1637 <dt><b>Vector constants</b></dt>
1638
1639 <dd>Vector constants are represented with notation similar to vector type
1640 definitions (a comma separated list of elements, surrounded by
1641 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1642 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
1643 href="#t_vector">vector type</a>, and the number and types of elements must
1644 match those specified by the type.
1645 </dd>
1646
1647 <dt><b>Zero initialization</b></dt>
1648
1649 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1650 value to zero of <em>any</em> type, including scalar and aggregate types.
1651 This is often used to avoid having to print large zero initializers (e.g. for
1652 large arrays) and is always exactly equivalent to using explicit zero
1653 initializers.
1654 </dd>
1655</dl>
1656
1657</div>
1658
1659<!-- ======================================================================= -->
1660<div class="doc_subsection">
1661 <a name="globalconstants">Global Variable and Function Addresses</a>
1662</div>
1663
1664<div class="doc_text">
1665
1666<p>The addresses of <a href="#globalvars">global variables</a> and <a
1667href="#functionstructure">functions</a> are always implicitly valid (link-time)
1668constants. These constants are explicitly referenced when the <a
1669href="#identifiers">identifier for the global</a> is used and always have <a
1670href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1671file:</p>
1672
1673<div class="doc_code">
1674<pre>
1675@X = global i32 17
1676@Y = global i32 42
1677@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
1678</pre>
1679</div>
1680
1681</div>
1682
1683<!-- ======================================================================= -->
1684<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
1685<div class="doc_text">
1686 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
1687 no specific value. Undefined values may be of any type and be used anywhere
1688 a constant is permitted.</p>
1689
1690 <p>Undefined values indicate to the compiler that the program is well defined
1691 no matter what value is used, giving the compiler more freedom to optimize.
1692 </p>
1693</div>
1694
1695<!-- ======================================================================= -->
1696<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1697</div>
1698
1699<div class="doc_text">
1700
1701<p>Constant expressions are used to allow expressions involving other constants
1702to be used as constants. Constant expressions may be of any <a
1703href="#t_firstclass">first class</a> type and may involve any LLVM operation
1704that does not have side effects (e.g. load and call are not supported). The
1705following is the syntax for constant expressions:</p>
1706
1707<dl>
1708 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1709 <dd>Truncate a constant to another type. The bit size of CST must be larger
1710 than the bit size of TYPE. Both types must be integers.</dd>
1711
1712 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1713 <dd>Zero extend a constant to another type. The bit size of CST must be
1714 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1715
1716 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1717 <dd>Sign extend a constant to another type. The bit size of CST must be
1718 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1719
1720 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1721 <dd>Truncate a floating point constant to another floating point type. The
1722 size of CST must be larger than the size of TYPE. Both types must be
1723 floating point.</dd>
1724
1725 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1726 <dd>Floating point extend a constant to another type. The size of CST must be
1727 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1728
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]1729 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1730 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1731 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1732 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1733 of the same number of elements. If the value won't fit in the integer type,
1734 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1735
1736 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
1737 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1738 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1739 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1740 of the same number of elements. If the value won't fit in the integer type,
1741 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1742
1743 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
1744 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1745 constant. TYPE must be a scalar or vector floating point type. CST must be of
1746 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1747 of the same number of elements. If the value won't fit in the floating point
1748 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1749
1750 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
1751 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1752 constant. TYPE must be a scalar or vector floating point type. CST must be of
1753 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1754 of the same number of elements. If the value won't fit in the floating point
1755 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1756
1757 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1758 <dd>Convert a pointer typed constant to the corresponding integer constant
1759 TYPE must be an integer type. CST must be of pointer type. The CST value is
1760 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1761
1762 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1763 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1764 pointer type. CST must be of integer type. The CST value is zero extended,
1765 truncated, or unchanged to make it fit in a pointer size. This one is
1766 <i>really</i> dangerous!</dd>
1767
1768 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
1769 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1770 identical (same number of bits). The conversion is done as if the CST value
1771 was stored to memory and read back as TYPE. In other words, no bits change
1772 with this operator, just the type. This can be used for conversion of
1773 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]1774 pointers it is only valid to cast to another pointer type. It is not valid
1775 to bitcast to or from an aggregate type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1776 </dd>
1777
1778 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1779
1780 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1781 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1782 instruction, the index list may have zero or more indexes, which are required
1783 to make sense for the type of "CSTPTR".</dd>
1784
1785 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1786
1787 <dd>Perform the <a href="#i_select">select operation</a> on
1788 constants.</dd>
1789
1790 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1791 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1792
1793 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1794 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
1795
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]1796 <dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
1797 <dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
1798
1799 <dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
1800 <dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
1801
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1802 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1803
1804 <dd>Perform the <a href="#i_extractelement">extractelement
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1805 operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1806
1807 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1808
1809 <dd>Perform the <a href="#i_insertelement">insertelement
1810 operation</a> on constants.</dd>
1811
1812
1813 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1814
1815 <dd>Perform the <a href="#i_shufflevector">shufflevector
1816 operation</a> on constants.</dd>
1817
1818 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1819
1820 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1821 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
1822 binary</a> operations. The constraints on operands are the same as those for
1823 the corresponding instruction (e.g. no bitwise operations on floating point
1824 values are allowed).</dd>
1825</dl>
1826</div>
1827
1828<!-- *********************************************************************** -->
1829<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1830<!-- *********************************************************************** -->
1831
1832<!-- ======================================================================= -->
1833<div class="doc_subsection">
1834<a name="inlineasm">Inline Assembler Expressions</a>
1835</div>
1836
1837<div class="doc_text">
1838
1839<p>
1840LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1841Module-Level Inline Assembly</a>) through the use of a special value. This
1842value represents the inline assembler as a string (containing the instructions
1843to emit), a list of operand constraints (stored as a string), and a flag that
1844indicates whether or not the inline asm expression has side effects. An example
1845inline assembler expression is:
1846</p>
1847
1848<div class="doc_code">
1849<pre>
1850i32 (i32) asm "bswap $0", "=r,r"
1851</pre>
1852</div>
1853
1854<p>
1855Inline assembler expressions may <b>only</b> be used as the callee operand of
1856a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1857</p>
1858
1859<div class="doc_code">
1860<pre>
1861%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
1862</pre>
1863</div>
1864
1865<p>
1866Inline asms with side effects not visible in the constraint list must be marked
1867as having side effects. This is done through the use of the
1868'<tt>sideeffect</tt>' keyword, like so:
1869</p>
1870
1871<div class="doc_code">
1872<pre>
1873call void asm sideeffect "eieio", ""()
1874</pre>
1875</div>
1876
1877<p>TODO: The format of the asm and constraints string still need to be
1878documented here. Constraints on what can be done (e.g. duplication, moving, etc
Chris Lattner1cdd64e2008-10-04 18:36:02 +0000[diff] [blame]1879need to be documented). This is probably best done by reference to another
1880document that covers inline asm from a holistic perspective.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1881</p>
1882
1883</div>
1884
1885<!-- *********************************************************************** -->
1886<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1887<!-- *********************************************************************** -->
1888
1889<div class="doc_text">
1890
1891<p>The LLVM instruction set consists of several different
1892classifications of instructions: <a href="#terminators">terminator
1893instructions</a>, <a href="#binaryops">binary instructions</a>,
1894<a href="#bitwiseops">bitwise binary instructions</a>, <a
1895 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1896instructions</a>.</p>
1897
1898</div>
1899
1900<!-- ======================================================================= -->
1901<div class="doc_subsection"> <a name="terminators">Terminator
1902Instructions</a> </div>
1903
1904<div class="doc_text">
1905
1906<p>As mentioned <a href="#functionstructure">previously</a>, every
1907basic block in a program ends with a "Terminator" instruction, which
1908indicates which block should be executed after the current block is
1909finished. These terminator instructions typically yield a '<tt>void</tt>'
1910value: they produce control flow, not values (the one exception being
1911the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
1912<p>There are six different terminator instructions: the '<a
1913 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1914instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
1915the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1916 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1917 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
1918
1919</div>
1920
1921<!-- _______________________________________________________________________ -->
1922<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1923Instruction</a> </div>
1924<div class="doc_text">
1925<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]1926<pre>
1927 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]1928 ret void <i>; Return from void function</i>
1929</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1930
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1931<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1932
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]1933<p>The '<tt>ret</tt>' instruction is used to return control flow (and
1934optionally a value) from a function back to the caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1935<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]1936returns a value and then causes control flow, and one that just causes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1937control flow to occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1938
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1939<h5>Arguments:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1940
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]1941<p>The '<tt>ret</tt>' instruction optionally accepts a single argument,
1942the return value. The type of the return value must be a
1943'<a href="#t_firstclass">first class</a>' type.</p>
1944
1945<p>A function is not <a href="#wellformed">well formed</a> if
1946it it has a non-void return type and contains a '<tt>ret</tt>'
1947instruction with no return value or a return value with a type that
1948does not match its type, or if it has a void return type and contains
1949a '<tt>ret</tt>' instruction with a return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1950
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1951<h5>Semantics:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1952
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1953<p>When the '<tt>ret</tt>' instruction is executed, control flow
1954returns back to the calling function's context. If the caller is a "<a
1955 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
1956the instruction after the call. If the caller was an "<a
1957 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
1958at the beginning of the "normal" destination block. If the instruction
1959returns a value, that value shall set the call or invoke instruction's
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1960return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1961
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1962<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1963
1964<pre>
1965 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1966 ret void <i>; Return from a void function</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]1967 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]1968</pre>
1969</div>
1970<!-- _______________________________________________________________________ -->
1971<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
1972<div class="doc_text">
1973<h5>Syntax:</h5>
1974<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
1975</pre>
1976<h5>Overview:</h5>
1977<p>The '<tt>br</tt>' instruction is used to cause control flow to
1978transfer to a different basic block in the current function. There are
1979two forms of this instruction, corresponding to a conditional branch
1980and an unconditional branch.</p>
1981<h5>Arguments:</h5>
1982<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
1983single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
1984unconditional form of the '<tt>br</tt>' instruction takes a single
1985'<tt>label</tt>' value as a target.</p>
1986<h5>Semantics:</h5>
1987<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
1988argument is evaluated. If the value is <tt>true</tt>, control flows
1989to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1990control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
1991<h5>Example:</h5>
1992<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
1993 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
1994</div>
1995<!-- _______________________________________________________________________ -->
1996<div class="doc_subsubsection">
1997 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1998</div>
1999
2000<div class="doc_text">
2001<h5>Syntax:</h5>
2002
2003<pre>
2004 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2005</pre>
2006
2007<h5>Overview:</h5>
2008
2009<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
2010several different places. It is a generalization of the '<tt>br</tt>'
2011instruction, allowing a branch to occur to one of many possible
2012destinations.</p>
2013
2014
2015<h5>Arguments:</h5>
2016
2017<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
2018comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
2019an array of pairs of comparison value constants and '<tt>label</tt>'s. The
2020table is not allowed to contain duplicate constant entries.</p>
2021
2022<h5>Semantics:</h5>
2023
2024<p>The <tt>switch</tt> instruction specifies a table of values and
2025destinations. When the '<tt>switch</tt>' instruction is executed, this
2026table is searched for the given value. If the value is found, control flow is
2027transfered to the corresponding destination; otherwise, control flow is
2028transfered to the default destination.</p>
2029
2030<h5>Implementation:</h5>
2031
2032<p>Depending on properties of the target machine and the particular
2033<tt>switch</tt> instruction, this instruction may be code generated in different
2034ways. For example, it could be generated as a series of chained conditional
2035branches or with a lookup table.</p>
2036
2037<h5>Example:</h5>
2038
2039<pre>
2040 <i>; Emulate a conditional br instruction</i>
2041 %Val = <a href="#i_zext">zext</a> i1 %value to i32
2042 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
2043
2044 <i>; Emulate an unconditional br instruction</i>
2045 switch i32 0, label %dest [ ]
2046
2047 <i>; Implement a jump table:</i>
2048 switch i32 %val, label %otherwise [ i32 0, label %onzero
2049 i32 1, label %onone
2050 i32 2, label %ontwo ]
2051</pre>
2052</div>
2053
2054<!-- _______________________________________________________________________ -->
2055<div class="doc_subsubsection">
2056 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2057</div>
2058
2059<div class="doc_text">
2060
2061<h5>Syntax:</h5>
2062
2063<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2064 &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]2065 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2066</pre>
2067
2068<h5>Overview:</h5>
2069
2070<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
2071function, with the possibility of control flow transfer to either the
2072'<tt>normal</tt>' label or the
2073'<tt>exception</tt>' label. If the callee function returns with the
2074"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
2075"normal" label. If the callee (or any indirect callees) returns with the "<a
2076href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2077continued at the dynamically nearest "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2078
2079<h5>Arguments:</h5>
2080
2081<p>This instruction requires several arguments:</p>
2082
2083<ol>
2084 <li>
2085 The optional "cconv" marker indicates which <a href="#callingconv">calling
2086 convention</a> the call should use. If none is specified, the call defaults
2087 to using C calling conventions.
2088 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2089
2090 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
2091 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
2092 and '<tt>inreg</tt>' attributes are valid here.</li>
2093
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2094 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
2095 function value being invoked. In most cases, this is a direct function
2096 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
2097 an arbitrary pointer to function value.
2098 </li>
2099
2100 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
2101 function to be invoked. </li>
2102
2103 <li>'<tt>function args</tt>': argument list whose types match the function
2104 signature argument types. If the function signature indicates the function
2105 accepts a variable number of arguments, the extra arguments can be
2106 specified. </li>
2107
2108 <li>'<tt>normal label</tt>': the label reached when the called function
2109 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2110
2111 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2112 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2113
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2114 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2115 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2116 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2117</ol>
2118
2119<h5>Semantics:</h5>
2120
2121<p>This instruction is designed to operate as a standard '<tt><a
2122href="#i_call">call</a></tt>' instruction in most regards. The primary
2123difference is that it establishes an association with a label, which is used by
2124the runtime library to unwind the stack.</p>
2125
2126<p>This instruction is used in languages with destructors to ensure that proper
2127cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2128exception. Additionally, this is important for implementation of
2129'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2130
2131<h5>Example:</h5>
2132<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2133 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2134 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2135 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2136 unwind label %TestCleanup <i>; {i32}:retval set</i>
2137</pre>
2138</div>
2139
2140
2141<!-- _______________________________________________________________________ -->
2142
2143<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2144Instruction</a> </div>
2145
2146<div class="doc_text">
2147
2148<h5>Syntax:</h5>
2149<pre>
2150 unwind
2151</pre>
2152
2153<h5>Overview:</h5>
2154
2155<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2156at the first callee in the dynamic call stack which used an <a
2157href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2158primarily used to implement exception handling.</p>
2159
2160<h5>Semantics:</h5>
2161
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2162<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2163immediately halt. The dynamic call stack is then searched for the first <a
2164href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2165execution continues at the "exceptional" destination block specified by the
2166<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2167dynamic call chain, undefined behavior results.</p>
2168</div>
2169
2170<!-- _______________________________________________________________________ -->
2171
2172<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2173Instruction</a> </div>
2174
2175<div class="doc_text">
2176
2177<h5>Syntax:</h5>
2178<pre>
2179 unreachable
2180</pre>
2181
2182<h5>Overview:</h5>
2183
2184<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2185instruction is used to inform the optimizer that a particular portion of the
2186code is not reachable. This can be used to indicate that the code after a
2187no-return function cannot be reached, and other facts.</p>
2188
2189<h5>Semantics:</h5>
2190
2191<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2192</div>
2193
2194
2195
2196<!-- ======================================================================= -->
2197<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
2198<div class="doc_text">
2199<p>Binary operators are used to do most of the computation in a
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2200program. They require two operands of the same type, execute an operation on them, and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2201produce a single value. The operands might represent
2202multiple 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]2203The result value has the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2204<p>There are several different binary operators:</p>
2205</div>
2206<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2207<div class="doc_subsubsection">
2208 <a name="i_add">'<tt>add</tt>' Instruction</a>
2209</div>
2210
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2211<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2212
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2213<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2214
2215<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2216 &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]2217</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2218
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2219<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2220
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2221<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2222
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2223<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2224
2225<p>The two arguments to the '<tt>add</tt>' instruction must be <a
2226 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
2227 <a href="#t_vector">vector</a> values. Both arguments must have identical
2228 types.</p>
2229
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2230<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2231
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2232<p>The value produced is the integer or floating point sum of the two
2233operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2234
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2235<p>If an integer sum has unsigned overflow, the result returned is the
2236mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2237the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2238
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2239<p>Because LLVM integers use a two's complement representation, this
2240instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2241
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2242<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2243
2244<pre>
2245 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2246</pre>
2247</div>
2248<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2249<div class="doc_subsubsection">
2250 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2251</div>
2252
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2253<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2254
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2255<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2256
2257<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2258 &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]2259</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2260
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2261<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2262
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2263<p>The '<tt>sub</tt>' instruction returns the difference of its two
2264operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2265
2266<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2267'<tt>neg</tt>' instruction present in most other intermediate
2268representations.</p>
2269
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2270<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2271
2272<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
2273 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2274 or <a href="#t_vector">vector</a> values. Both arguments must have identical
2275 types.</p>
2276
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2277<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2278
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2279<p>The value produced is the integer or floating point difference of
2280the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2281
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2282<p>If an integer difference has unsigned overflow, the result returned is the
2283mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2284the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2285
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2286<p>Because LLVM integers use a two's complement representation, this
2287instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2288
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2289<h5>Example:</h5>
2290<pre>
2291 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2292 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2293</pre>
2294</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2295
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2296<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2297<div class="doc_subsubsection">
2298 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2299</div>
2300
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2301<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2302
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2303<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2304<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]2305</pre>
2306<h5>Overview:</h5>
2307<p>The '<tt>mul</tt>' instruction returns the product of its two
2308operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2309
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2310<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2311
2312<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
2313href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2314or <a href="#t_vector">vector</a> values. Both arguments must have identical
2315types.</p>
2316
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2317<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2318
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2319<p>The value produced is the integer or floating point product of the
2320two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2321
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2322<p>If the result of an integer multiplication has unsigned overflow,
2323the result returned is the mathematical result modulo
23242<sup>n</sup>, where n is the bit width of the result.</p>
2325<p>Because LLVM integers use a two's complement representation, and the
2326result is the same width as the operands, this instruction returns the
2327correct result for both signed and unsigned integers. If a full product
2328(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2329should be sign-extended or zero-extended as appropriate to the
2330width of the full product.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2331<h5>Example:</h5>
2332<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
2333</pre>
2334</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2335
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2336<!-- _______________________________________________________________________ -->
2337<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2338</a></div>
2339<div class="doc_text">
2340<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2341<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]2342</pre>
2343<h5>Overview:</h5>
2344<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2345operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2346
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2347<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2348
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2349<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2350<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2351values. Both arguments must have identical types.</p>
2352
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2353<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2354
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2355<p>The value produced is the unsigned integer quotient of the two operands.</p>
2356<p>Note that unsigned integer division and signed integer division are distinct
2357operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2358<p>Division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2359<h5>Example:</h5>
2360<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2361</pre>
2362</div>
2363<!-- _______________________________________________________________________ -->
2364<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2365</a> </div>
2366<div class="doc_text">
2367<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2368<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2369 &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]2370</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2371
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2372<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2373
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2374<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2375operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2376
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2377<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2378
2379<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2380<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2381values. Both arguments must have identical types.</p>
2382
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2383<h5>Semantics:</h5>
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2384<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]2385<p>Note that signed integer division and unsigned integer division are distinct
2386operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2387<p>Division by zero leads to undefined behavior. Overflow also leads to
2388undefined behavior; this is a rare case, but can occur, for example,
2389by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2390<h5>Example:</h5>
2391<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2392</pre>
2393</div>
2394<!-- _______________________________________________________________________ -->
2395<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2396Instruction</a> </div>
2397<div class="doc_text">
2398<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2399<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2400 &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]2401</pre>
2402<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2403
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2404<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
2405operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2406
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2407<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2408
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2409<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2410<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2411of floating point values. Both arguments must have identical types.</p>
2412
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2413<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2414
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2415<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2416
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2417<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2418
2419<pre>
2420 &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]2421</pre>
2422</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2423
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2424<!-- _______________________________________________________________________ -->
2425<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2426</div>
2427<div class="doc_text">
2428<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2429<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]2430</pre>
2431<h5>Overview:</h5>
2432<p>The '<tt>urem</tt>' instruction returns the remainder from the
2433unsigned division of its two arguments.</p>
2434<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2435<p>The two arguments to the '<tt>urem</tt>' instruction must be
2436<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2437values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2438<h5>Semantics:</h5>
2439<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2440This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2441<p>Note that unsigned integer remainder and signed integer remainder are
2442distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2443<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2444<h5>Example:</h5>
2445<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2446</pre>
2447
2448</div>
2449<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2450<div class="doc_subsubsection">
2451 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2452</div>
2453
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2454<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2455
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2456<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2457
2458<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2459 &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]2460</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2461
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2462<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2463
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2464<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman3e3fd8c2007-11-05 23:35:22 +0000[diff] [blame]2465signed division of its two operands. This instruction can also take
2466<a href="#t_vector">vector</a> versions of the values in which case
2467the elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]2468
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2469<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2470
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2471<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2472<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2473values. Both arguments must have identical types.</p>
2474
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2475<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2476
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2477<p>This instruction returns the <i>remainder</i> of a division (where the result
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2478has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
2479operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2480a value. For more information about the difference, see <a
2481 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2482Math Forum</a>. For a table of how this is implemented in various languages,
2483please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
2484Wikipedia: modulo operation</a>.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2485<p>Note that signed integer remainder and unsigned integer remainder are
2486distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2487<p>Taking the remainder of a division by zero leads to undefined behavior.
2488Overflow also leads to undefined behavior; this is a rare case, but can occur,
2489for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2490(The remainder doesn't actually overflow, but this rule lets srem be
2491implemented using instructions that return both the result of the division
2492and the remainder.)</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2493<h5>Example:</h5>
2494<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2495</pre>
2496
2497</div>
2498<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2499<div class="doc_subsubsection">
2500 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2501
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2502<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2503
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2504<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2505<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]2506</pre>
2507<h5>Overview:</h5>
2508<p>The '<tt>frem</tt>' instruction returns the remainder from the
2509division of its two operands.</p>
2510<h5>Arguments:</h5>
2511<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2512<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2513of floating point values. Both arguments must have identical types.</p>
2514
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2515<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2516
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2517<p>This instruction returns the <i>remainder</i> of a division.
2518The remainder has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2519
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2520<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2521
2522<pre>
2523 &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]2524</pre>
2525</div>
2526
2527<!-- ======================================================================= -->
2528<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2529Operations</a> </div>
2530<div class="doc_text">
2531<p>Bitwise binary operators are used to do various forms of
2532bit-twiddling in a program. They are generally very efficient
2533instructions and can commonly be strength reduced from other
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2534instructions. They require two operands of the same type, execute an operation on them,
2535and 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]2536</div>
2537
2538<!-- _______________________________________________________________________ -->
2539<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2540Instruction</a> </div>
2541<div class="doc_text">
2542<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2543<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]2544</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2545
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2546<h5>Overview:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2547
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2548<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2549the left a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2550
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2551<h5>Arguments:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2552
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2553<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2554 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2555type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2556
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2557<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2558
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2559<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
2560where n is the width of the result. If <tt>op2</tt> is (statically or dynamically) negative or
2561equal to or larger than the number of bits in <tt>op1</tt>, the result is undefined.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2562
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2563<h5>Example:</h5><pre>
2564 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2565 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2566 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2567 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2568</pre>
2569</div>
2570<!-- _______________________________________________________________________ -->
2571<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2572Instruction</a> </div>
2573<div class="doc_text">
2574<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2575<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]2576</pre>
2577
2578<h5>Overview:</h5>
2579<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2580operand shifted to the right a specified number of bits with zero fill.</p>
2581
2582<h5>Arguments:</h5>
2583<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2584<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]2585type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2586
2587<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2588
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2589<p>This instruction always performs a logical shift right operation. The most
2590significant bits of the result will be filled with zero bits after the
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2591shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
2592the number of bits in <tt>op1</tt>, the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2593
2594<h5>Example:</h5>
2595<pre>
2596 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2597 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2598 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2599 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2600 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2601</pre>
2602</div>
2603
2604<!-- _______________________________________________________________________ -->
2605<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2606Instruction</a> </div>
2607<div class="doc_text">
2608
2609<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2610<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]2611</pre>
2612
2613<h5>Overview:</h5>
2614<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2615operand shifted to the right a specified number of bits with sign extension.</p>
2616
2617<h5>Arguments:</h5>
2618<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2619<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]2620type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2621
2622<h5>Semantics:</h5>
2623<p>This instruction always performs an arithmetic shift right operation,
2624The most significant bits of the result will be filled with the sign bit
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2625of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
2626larger than the number of bits in <tt>op1</tt>, the result is undefined.
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2627</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2628
2629<h5>Example:</h5>
2630<pre>
2631 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2632 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2633 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2634 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2635 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2636</pre>
2637</div>
2638
2639<!-- _______________________________________________________________________ -->
2640<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2641Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2642
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2643<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2644
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2645<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2646
2647<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2648 &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]2649</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2650
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2651<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2652
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2653<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2654its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2655
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2656<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2657
2658<p>The two arguments to the '<tt>and</tt>' instruction must be
2659<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2660values. Both arguments must have identical types.</p>
2661
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2662<h5>Semantics:</h5>
2663<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
2664<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2665<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2666<table border="1" cellspacing="0" cellpadding="4">
2667 <tbody>
2668 <tr>
2669 <td>In0</td>
2670 <td>In1</td>
2671 <td>Out</td>
2672 </tr>
2673 <tr>
2674 <td>0</td>
2675 <td>0</td>
2676 <td>0</td>
2677 </tr>
2678 <tr>
2679 <td>0</td>
2680 <td>1</td>
2681 <td>0</td>
2682 </tr>
2683 <tr>
2684 <td>1</td>
2685 <td>0</td>
2686 <td>0</td>
2687 </tr>
2688 <tr>
2689 <td>1</td>
2690 <td>1</td>
2691 <td>1</td>
2692 </tr>
2693 </tbody>
2694</table>
2695</div>
2696<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2697<pre>
2698 &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]2699 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2700 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
2701</pre>
2702</div>
2703<!-- _______________________________________________________________________ -->
2704<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
2705<div class="doc_text">
2706<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2707<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]2708</pre>
2709<h5>Overview:</h5>
2710<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2711or of its two operands.</p>
2712<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2713
2714<p>The two arguments to the '<tt>or</tt>' instruction must be
2715<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2716values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2717<h5>Semantics:</h5>
2718<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
2719<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2720<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2721<table border="1" cellspacing="0" cellpadding="4">
2722 <tbody>
2723 <tr>
2724 <td>In0</td>
2725 <td>In1</td>
2726 <td>Out</td>
2727 </tr>
2728 <tr>
2729 <td>0</td>
2730 <td>0</td>
2731 <td>0</td>
2732 </tr>
2733 <tr>
2734 <td>0</td>
2735 <td>1</td>
2736 <td>1</td>
2737 </tr>
2738 <tr>
2739 <td>1</td>
2740 <td>0</td>
2741 <td>1</td>
2742 </tr>
2743 <tr>
2744 <td>1</td>
2745 <td>1</td>
2746 <td>1</td>
2747 </tr>
2748 </tbody>
2749</table>
2750</div>
2751<h5>Example:</h5>
2752<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2753 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2754 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
2755</pre>
2756</div>
2757<!-- _______________________________________________________________________ -->
2758<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2759Instruction</a> </div>
2760<div class="doc_text">
2761<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2762<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]2763</pre>
2764<h5>Overview:</h5>
2765<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2766or of its two operands. The <tt>xor</tt> is used to implement the
2767"one's complement" operation, which is the "~" operator in C.</p>
2768<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2769<p>The two arguments to the '<tt>xor</tt>' instruction must be
2770<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2771values. Both arguments must have identical types.</p>
2772
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2773<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2774
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2775<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
2776<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2777<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2778<table border="1" cellspacing="0" cellpadding="4">
2779 <tbody>
2780 <tr>
2781 <td>In0</td>
2782 <td>In1</td>
2783 <td>Out</td>
2784 </tr>
2785 <tr>
2786 <td>0</td>
2787 <td>0</td>
2788 <td>0</td>
2789 </tr>
2790 <tr>
2791 <td>0</td>
2792 <td>1</td>
2793 <td>1</td>
2794 </tr>
2795 <tr>
2796 <td>1</td>
2797 <td>0</td>
2798 <td>1</td>
2799 </tr>
2800 <tr>
2801 <td>1</td>
2802 <td>1</td>
2803 <td>0</td>
2804 </tr>
2805 </tbody>
2806</table>
2807</div>
2808<p> </p>
2809<h5>Example:</h5>
2810<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2811 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2812 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2813 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
2814</pre>
2815</div>
2816
2817<!-- ======================================================================= -->
2818<div class="doc_subsection">
2819 <a name="vectorops">Vector Operations</a>
2820</div>
2821
2822<div class="doc_text">
2823
2824<p>LLVM supports several instructions to represent vector operations in a
2825target-independent manner. These instructions cover the element-access and
2826vector-specific operations needed to process vectors effectively. While LLVM
2827does directly support these vector operations, many sophisticated algorithms
2828will want to use target-specific intrinsics to take full advantage of a specific
2829target.</p>
2830
2831</div>
2832
2833<!-- _______________________________________________________________________ -->
2834<div class="doc_subsubsection">
2835 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2836</div>
2837
2838<div class="doc_text">
2839
2840<h5>Syntax:</h5>
2841
2842<pre>
2843 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
2844</pre>
2845
2846<h5>Overview:</h5>
2847
2848<p>
2849The '<tt>extractelement</tt>' instruction extracts a single scalar
2850element from a vector at a specified index.
2851</p>
2852
2853
2854<h5>Arguments:</h5>
2855
2856<p>
2857The first operand of an '<tt>extractelement</tt>' instruction is a
2858value of <a href="#t_vector">vector</a> type. The second operand is
2859an index indicating the position from which to extract the element.
2860The index may be a variable.</p>
2861
2862<h5>Semantics:</h5>
2863
2864<p>
2865The result is a scalar of the same type as the element type of
2866<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2867<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2868results are undefined.
2869</p>
2870
2871<h5>Example:</h5>
2872
2873<pre>
2874 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
2875</pre>
2876</div>
2877
2878
2879<!-- _______________________________________________________________________ -->
2880<div class="doc_subsubsection">
2881 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2882</div>
2883
2884<div class="doc_text">
2885
2886<h5>Syntax:</h5>
2887
2888<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]2889 &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]2890</pre>
2891
2892<h5>Overview:</h5>
2893
2894<p>
2895The '<tt>insertelement</tt>' instruction inserts a scalar
2896element into a vector at a specified index.
2897</p>
2898
2899
2900<h5>Arguments:</h5>
2901
2902<p>
2903The first operand of an '<tt>insertelement</tt>' instruction is a
2904value of <a href="#t_vector">vector</a> type. The second operand is a
2905scalar value whose type must equal the element type of the first
2906operand. The third operand is an index indicating the position at
2907which to insert the value. The index may be a variable.</p>
2908
2909<h5>Semantics:</h5>
2910
2911<p>
2912The result is a vector of the same type as <tt>val</tt>. Its
2913element values are those of <tt>val</tt> except at position
2914<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2915exceeds the length of <tt>val</tt>, the results are undefined.
2916</p>
2917
2918<h5>Example:</h5>
2919
2920<pre>
2921 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
2922</pre>
2923</div>
2924
2925<!-- _______________________________________________________________________ -->
2926<div class="doc_subsubsection">
2927 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2928</div>
2929
2930<div class="doc_text">
2931
2932<h5>Syntax:</h5>
2933
2934<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame^]2935 &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]2936</pre>
2937
2938<h5>Overview:</h5>
2939
2940<p>
2941The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame^]2942from two input vectors, returning a vector with the same element type as
2943the input and length that is the same as the shuffle mask.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2944</p>
2945
2946<h5>Arguments:</h5>
2947
2948<p>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame^]2949The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2950with types that match each other. The third argument is a shuffle mask whose
2951element type is always 'i32'. The result of the instruction is a vector whose
2952length is the same as the shuffle mask and whose element type is the same as
2953the element type of the first two operands.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2954</p>
2955
2956<p>
2957The shuffle mask operand is required to be a constant vector with either
2958constant integer or undef values.
2959</p>
2960
2961<h5>Semantics:</h5>
2962
2963<p>
2964The elements of the two input vectors are numbered from left to right across
2965both of the vectors. The shuffle mask operand specifies, for each element of
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame^]2966the result vector, which element of the two input vectors the result element
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2967gets. The element selector may be undef (meaning "don't care") and the second
2968operand may be undef if performing a shuffle from only one vector.
2969</p>
2970
2971<h5>Example:</h5>
2972
2973<pre>
2974 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
2975 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
2976 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2977 &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^]2978 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
2979 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
2980 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
2981 &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]2982</pre>
2983</div>
2984
2985
2986<!-- ======================================================================= -->
2987<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2988 <a name="aggregateops">Aggregate Operations</a>
2989</div>
2990
2991<div class="doc_text">
2992
2993<p>LLVM supports several instructions for working with aggregate values.
2994</p>
2995
2996</div>
2997
2998<!-- _______________________________________________________________________ -->
2999<div class="doc_subsubsection">
3000 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3001</div>
3002
3003<div class="doc_text">
3004
3005<h5>Syntax:</h5>
3006
3007<pre>
3008 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3009</pre>
3010
3011<h5>Overview:</h5>
3012
3013<p>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3014The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3015or array element from an aggregate value.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3016</p>
3017
3018
3019<h5>Arguments:</h5>
3020
3021<p>
3022The first operand of an '<tt>extractvalue</tt>' instruction is a
3023value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3024type. The operands are constant indices to specify which value to extract
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3025in a similar manner as indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3026'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3027</p>
3028
3029<h5>Semantics:</h5>
3030
3031<p>
3032The result is the value at the position in the aggregate specified by
3033the index operands.
3034</p>
3035
3036<h5>Example:</h5>
3037
3038<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3039 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3040</pre>
3041</div>
3042
3043
3044<!-- _______________________________________________________________________ -->
3045<div class="doc_subsubsection">
3046 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3047</div>
3048
3049<div class="doc_text">
3050
3051<h5>Syntax:</h5>
3052
3053<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3054 &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]3055</pre>
3056
3057<h5>Overview:</h5>
3058
3059<p>
3060The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3061into a struct field or array element in an aggregate.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3062</p>
3063
3064
3065<h5>Arguments:</h5>
3066
3067<p>
3068The first operand of an '<tt>insertvalue</tt>' instruction is a
3069value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
3070The second operand is a first-class value to insert.
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]3071The following operands are constant indices
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3072indicating the position at which to insert the value in a similar manner as
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3073indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3074'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3075The value to insert must have the same type as the value identified
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3076by the indices.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3077</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3078
3079<h5>Semantics:</h5>
3080
3081<p>
3082The result is an aggregate of the same type as <tt>val</tt>. Its
3083value is that of <tt>val</tt> except that the value at the position
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3084specified by the indices is that of <tt>elt</tt>.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3085</p>
3086
3087<h5>Example:</h5>
3088
3089<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3090 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3091</pre>
3092</div>
3093
3094
3095<!-- ======================================================================= -->
3096<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3097 <a name="memoryops">Memory Access and Addressing Operations</a>
3098</div>
3099
3100<div class="doc_text">
3101
3102<p>A key design point of an SSA-based representation is how it
3103represents memory. In LLVM, no memory locations are in SSA form, which
3104makes things very simple. This section describes how to read, write,
3105allocate, and free memory in LLVM.</p>
3106
3107</div>
3108
3109<!-- _______________________________________________________________________ -->
3110<div class="doc_subsubsection">
3111 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3112</div>
3113
3114<div class="doc_text">
3115
3116<h5>Syntax:</h5>
3117
3118<pre>
3119 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3120</pre>
3121
3122<h5>Overview:</h5>
3123
3124<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3125heap and returns a pointer to it. The object is always allocated in the generic
3126address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3127
3128<h5>Arguments:</h5>
3129
3130<p>The '<tt>malloc</tt>' instruction allocates
3131<tt>sizeof(&lt;type&gt;)*NumElements</tt>
3132bytes of memory from the operating system and returns a pointer of the
3133appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3134number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3135If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3136be aligned to at least that boundary. If not specified, or if zero, the target can
3137choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3138
3139<p>'<tt>type</tt>' must be a sized type.</p>
3140
3141<h5>Semantics:</h5>
3142
3143<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3144a pointer is returned. The result of a zero byte allocattion is undefined. The
3145result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3146
3147<h5>Example:</h5>
3148
3149<pre>
3150 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
3151
3152 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3153 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3154 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3155 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3156 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3157</pre>
3158</div>
3159
3160<!-- _______________________________________________________________________ -->
3161<div class="doc_subsubsection">
3162 <a name="i_free">'<tt>free</tt>' Instruction</a>
3163</div>
3164
3165<div class="doc_text">
3166
3167<h5>Syntax:</h5>
3168
3169<pre>
3170 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
3171</pre>
3172
3173<h5>Overview:</h5>
3174
3175<p>The '<tt>free</tt>' instruction returns memory back to the unused
3176memory heap to be reallocated in the future.</p>
3177
3178<h5>Arguments:</h5>
3179
3180<p>'<tt>value</tt>' shall be a pointer value that points to a value
3181that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3182instruction.</p>
3183
3184<h5>Semantics:</h5>
3185
3186<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner329d6532008-04-19 22:41:32 +0000[diff] [blame]3187after this instruction executes. If the pointer is null, the operation
3188is a noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3189
3190<h5>Example:</h5>
3191
3192<pre>
3193 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
3194 free [4 x i8]* %array
3195</pre>
3196</div>
3197
3198<!-- _______________________________________________________________________ -->
3199<div class="doc_subsubsection">
3200 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3201</div>
3202
3203<div class="doc_text">
3204
3205<h5>Syntax:</h5>
3206
3207<pre>
3208 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3209</pre>
3210
3211<h5>Overview:</h5>
3212
3213<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3214currently executing function, to be automatically released when this function
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3215returns to its caller. The object is always allocated in the generic address
3216space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3217
3218<h5>Arguments:</h5>
3219
3220<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
3221bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3222appropriate type to the program. If "NumElements" is specified, it is the
3223number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3224If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3225to be aligned to at least that boundary. If not specified, or if zero, the target
3226can choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3227
3228<p>'<tt>type</tt>' may be any sized type.</p>
3229
3230<h5>Semantics:</h5>
3231
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3232<p>Memory is allocated; a pointer is returned. The operation is undefiend if
3233there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3234memory is automatically released when the function returns. The '<tt>alloca</tt>'
3235instruction is commonly used to represent automatic variables that must
3236have an address available. When the function returns (either with the <tt><a
3237 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]3238instructions), the memory is reclaimed. Allocating zero bytes
3239is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3240
3241<h5>Example:</h5>
3242
3243<pre>
3244 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3245 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3246 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3247 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
3248</pre>
3249</div>
3250
3251<!-- _______________________________________________________________________ -->
3252<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3253Instruction</a> </div>
3254<div class="doc_text">
3255<h5>Syntax:</h5>
3256<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>
3257<h5>Overview:</h5>
3258<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
3259<h5>Arguments:</h5>
3260<p>The argument to the '<tt>load</tt>' instruction specifies the memory
3261address from which to load. The pointer must point to a <a
3262 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3263marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
3264the number or order of execution of this <tt>load</tt> with other
3265volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3266instructions. </p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3267<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3268The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3269(that is, the alignment of the memory address). A value of 0 or an
3270omitted "align" argument means that the operation has the preferential
3271alignment for the target. It is the responsibility of the code emitter
3272to ensure that the alignment information is correct. Overestimating
3273the alignment results in an undefined behavior. Underestimating the
3274alignment may produce less efficient code. An alignment of 1 is always
3275safe.
3276</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3277<h5>Semantics:</h5>
3278<p>The location of memory pointed to is loaded.</p>
3279<h5>Examples:</h5>
3280<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3281 <a
3282 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3283 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3284</pre>
3285</div>
3286<!-- _______________________________________________________________________ -->
3287<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3288Instruction</a> </div>
3289<div class="doc_text">
3290<h5>Syntax:</h5>
3291<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3292 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3293</pre>
3294<h5>Overview:</h5>
3295<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
3296<h5>Arguments:</h5>
3297<p>There are two arguments to the '<tt>store</tt>' instruction: a value
3298to 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]3299operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3300of the '<tt>&lt;value&gt;</tt>'
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3301operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
3302optimizer is not allowed to modify the number or order of execution of
3303this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3304 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3305<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3306The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3307(that is, the alignment of the memory address). A value of 0 or an
3308omitted "align" argument means that the operation has the preferential
3309alignment for the target. It is the responsibility of the code emitter
3310to ensure that the alignment information is correct. Overestimating
3311the alignment results in an undefined behavior. Underestimating the
3312alignment may produce less efficient code. An alignment of 1 is always
3313safe.
3314</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3315<h5>Semantics:</h5>
3316<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
3317at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
3318<h5>Example:</h5>
3319<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3320 store i32 3, i32* %ptr <i>; yields {void}</i>
3321 %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]3322</pre>
3323</div>
3324
3325<!-- _______________________________________________________________________ -->
3326<div class="doc_subsubsection">
3327 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3328</div>
3329
3330<div class="doc_text">
3331<h5>Syntax:</h5>
3332<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3333 &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]3334</pre>
3335
3336<h5>Overview:</h5>
3337
3338<p>
3339The '<tt>getelementptr</tt>' instruction is used to get the address of a
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3340subelement of an aggregate data structure. It performs address calculation only
3341and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3342
3343<h5>Arguments:</h5>
3344
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3345<p>The first argument is always a pointer, and forms the basis of the
3346calculation. The remaining arguments are indices, that indicate which of the
3347elements of the aggregate object are indexed. The interpretation of each index
3348is dependent on the type being indexed into. The first index always indexes the
3349pointer value given as the first argument, the second index indexes a value of
3350the type pointed to (not necessarily the value directly pointed to, since the
3351first index can be non-zero), etc. The first type indexed into must be a pointer
3352value, subsequent types can be arrays, vectors and structs. Note that subsequent
3353types being indexed into can never be pointers, since that would require loading
3354the pointer before continuing calculation.</p>
3355
3356<p>The type of each index argument depends on the type it is indexing into.
3357When indexing into a (packed) structure, only <tt>i32</tt> integer
3358<b>constants</b> are allowed. When indexing into an array, pointer or vector,
3359only integers of 32 or 64 bits are allowed (also non-constants). 32-bit values
3360will be sign extended to 64-bits if required.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3361
3362<p>For example, let's consider a C code fragment and how it gets
3363compiled to LLVM:</p>
3364
3365<div class="doc_code">
3366<pre>
3367struct RT {
3368 char A;
3369 int B[10][20];
3370 char C;
3371};
3372struct ST {
3373 int X;
3374 double Y;
3375 struct RT Z;
3376};
3377
3378int *foo(struct ST *s) {
3379 return &amp;s[1].Z.B[5][13];
3380}
3381</pre>
3382</div>
3383
3384<p>The LLVM code generated by the GCC frontend is:</p>
3385
3386<div class="doc_code">
3387<pre>
3388%RT = type { i8 , [10 x [20 x i32]], i8 }
3389%ST = type { i32, double, %RT }
3390
3391define i32* %foo(%ST* %s) {
3392entry:
3393 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3394 ret i32* %reg
3395}
3396</pre>
3397</div>
3398
3399<h5>Semantics:</h5>
3400
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3401<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
3402type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3403}</tt>' type, a structure. The second index indexes into the third element of
3404the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3405i8 }</tt>' type, another structure. The third index indexes into the second
3406element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3407array. The two dimensions of the array are subscripted into, yielding an
3408'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3409to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
3410
3411<p>Note that it is perfectly legal to index partially through a
3412structure, returning a pointer to an inner element. Because of this,
3413the LLVM code for the given testcase is equivalent to:</p>
3414
3415<pre>
3416 define i32* %foo(%ST* %s) {
3417 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3418 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3419 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3420 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3421 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3422 ret i32* %t5
3423 }
3424</pre>
3425
3426<p>Note that it is undefined to access an array out of bounds: array and
3427pointer indexes must always be within the defined bounds of the array type.
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]3428The one exception for this rule is zero length arrays. These arrays are
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3429defined to be accessible as variable length arrays, which requires access
3430beyond the zero'th element.</p>
3431
3432<p>The getelementptr instruction is often confusing. For some more insight
3433into how it works, see <a href="GetElementPtr.html">the getelementptr
3434FAQ</a>.</p>
3435
3436<h5>Example:</h5>
3437
3438<pre>
3439 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3440 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3441 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3442 %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]3443 <i>; yields i8*:eptr</i>
3444 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3445</pre>
3446</div>
3447
3448<!-- ======================================================================= -->
3449<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3450</div>
3451<div class="doc_text">
3452<p>The instructions in this category are the conversion instructions (casting)
3453which all take a single operand and a type. They perform various bit conversions
3454on the operand.</p>
3455</div>
3456
3457<!-- _______________________________________________________________________ -->
3458<div class="doc_subsubsection">
3459 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3460</div>
3461<div class="doc_text">
3462
3463<h5>Syntax:</h5>
3464<pre>
3465 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3466</pre>
3467
3468<h5>Overview:</h5>
3469<p>
3470The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3471</p>
3472
3473<h5>Arguments:</h5>
3474<p>
3475The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3476be an <a href="#t_integer">integer</a> type, and a type that specifies the size
3477and type of the result, which must be an <a href="#t_integer">integer</a>
3478type. The bit size of <tt>value</tt> must be larger than the bit size of
3479<tt>ty2</tt>. Equal sized types are not allowed.</p>
3480
3481<h5>Semantics:</h5>
3482<p>
3483The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
3484and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3485larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3486It will always truncate bits.</p>
3487
3488<h5>Example:</h5>
3489<pre>
3490 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3491 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3492 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
3493</pre>
3494</div>
3495
3496<!-- _______________________________________________________________________ -->
3497<div class="doc_subsubsection">
3498 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3499</div>
3500<div class="doc_text">
3501
3502<h5>Syntax:</h5>
3503<pre>
3504 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3505</pre>
3506
3507<h5>Overview:</h5>
3508<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3509<tt>ty2</tt>.</p>
3510
3511
3512<h5>Arguments:</h5>
3513<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
3514<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3515also be of <a href="#t_integer">integer</a> type. The bit size of the
3516<tt>value</tt> must be smaller than the bit size of the destination type,
3517<tt>ty2</tt>.</p>
3518
3519<h5>Semantics:</h5>
3520<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
3521bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
3522
3523<p>When zero extending from i1, the result will always be either 0 or 1.</p>
3524
3525<h5>Example:</h5>
3526<pre>
3527 %X = zext i32 257 to i64 <i>; yields i64:257</i>
3528 %Y = zext i1 true to i32 <i>; yields i32:1</i>
3529</pre>
3530</div>
3531
3532<!-- _______________________________________________________________________ -->
3533<div class="doc_subsubsection">
3534 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3535</div>
3536<div class="doc_text">
3537
3538<h5>Syntax:</h5>
3539<pre>
3540 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3541</pre>
3542
3543<h5>Overview:</h5>
3544<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3545
3546<h5>Arguments:</h5>
3547<p>
3548The '<tt>sext</tt>' instruction takes a value to cast, which must be of
3549<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3550also be of <a href="#t_integer">integer</a> type. The bit size of the
3551<tt>value</tt> must be smaller than the bit size of the destination type,
3552<tt>ty2</tt>.</p>
3553
3554<h5>Semantics:</h5>
3555<p>
3556The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3557bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
3558the type <tt>ty2</tt>.</p>
3559
3560<p>When sign extending from i1, the extension always results in -1 or 0.</p>
3561
3562<h5>Example:</h5>
3563<pre>
3564 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
3565 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
3566</pre>
3567</div>
3568
3569<!-- _______________________________________________________________________ -->
3570<div class="doc_subsubsection">
3571 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3572</div>
3573
3574<div class="doc_text">
3575
3576<h5>Syntax:</h5>
3577
3578<pre>
3579 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3580</pre>
3581
3582<h5>Overview:</h5>
3583<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3584<tt>ty2</tt>.</p>
3585
3586
3587<h5>Arguments:</h5>
3588<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3589 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3590cast it to. The size of <tt>value</tt> must be larger than the size of
3591<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3592<i>no-op cast</i>.</p>
3593
3594<h5>Semantics:</h5>
3595<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3596<a href="#t_floating">floating point</a> type to a smaller
3597<a href="#t_floating">floating point</a> type. If the value cannot fit within
3598the destination type, <tt>ty2</tt>, then the results are undefined.</p>
3599
3600<h5>Example:</h5>
3601<pre>
3602 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3603 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3604</pre>
3605</div>
3606
3607<!-- _______________________________________________________________________ -->
3608<div class="doc_subsubsection">
3609 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3610</div>
3611<div class="doc_text">
3612
3613<h5>Syntax:</h5>
3614<pre>
3615 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3616</pre>
3617
3618<h5>Overview:</h5>
3619<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3620floating point value.</p>
3621
3622<h5>Arguments:</h5>
3623<p>The '<tt>fpext</tt>' instruction takes a
3624<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
3625and a <a href="#t_floating">floating point</a> type to cast it to. The source
3626type must be smaller than the destination type.</p>
3627
3628<h5>Semantics:</h5>
3629<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
3630<a href="#t_floating">floating point</a> type to a larger
3631<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
3632used to make a <i>no-op cast</i> because it always changes bits. Use
3633<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
3634
3635<h5>Example:</h5>
3636<pre>
3637 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3638 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3639</pre>
3640</div>
3641
3642<!-- _______________________________________________________________________ -->
3643<div class="doc_subsubsection">
3644 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
3645</div>
3646<div class="doc_text">
3647
3648<h5>Syntax:</h5>
3649<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3650 &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]3651</pre>
3652
3653<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3654<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3655unsigned integer equivalent of type <tt>ty2</tt>.
3656</p>
3657
3658<h5>Arguments:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3659<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]3660scalar or vector <a href="#t_floating">floating point</a> value, and a type
3661to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3662type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3663vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3664
3665<h5>Semantics:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3666<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3667<a href="#t_floating">floating point</a> operand into the nearest (rounding
3668towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3669the results are undefined.</p>
3670
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3671<h5>Example:</h5>
3672<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3673 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3674 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3675 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3676</pre>
3677</div>
3678
3679<!-- _______________________________________________________________________ -->
3680<div class="doc_subsubsection">
3681 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
3682</div>
3683<div class="doc_text">
3684
3685<h5>Syntax:</h5>
3686<pre>
3687 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3688</pre>
3689
3690<h5>Overview:</h5>
3691<p>The '<tt>fptosi</tt>' instruction converts
3692<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
3693</p>
3694
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3695<h5>Arguments:</h5>
3696<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]3697scalar or vector <a href="#t_floating">floating point</a> value, and a type
3698to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3699type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3700vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3701
3702<h5>Semantics:</h5>
3703<p>The '<tt>fptosi</tt>' instruction converts its
3704<a href="#t_floating">floating point</a> operand into the nearest (rounding
3705towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3706the results are undefined.</p>
3707
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3708<h5>Example:</h5>
3709<pre>
3710 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3711 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3712 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
3713</pre>
3714</div>
3715
3716<!-- _______________________________________________________________________ -->
3717<div class="doc_subsubsection">
3718 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
3719</div>
3720<div class="doc_text">
3721
3722<h5>Syntax:</h5>
3723<pre>
3724 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3725</pre>
3726
3727<h5>Overview:</h5>
3728<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
3729integer and converts that value to the <tt>ty2</tt> type.</p>
3730
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3731<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3732<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3733scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3734to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3735type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3736floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3737
3738<h5>Semantics:</h5>
3739<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
3740integer quantity and converts it to the corresponding floating point value. If
3741the value cannot fit in the floating point value, the results are undefined.</p>
3742
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3743<h5>Example:</h5>
3744<pre>
3745 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3746 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3747</pre>
3748</div>
3749
3750<!-- _______________________________________________________________________ -->
3751<div class="doc_subsubsection">
3752 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
3753</div>
3754<div class="doc_text">
3755
3756<h5>Syntax:</h5>
3757<pre>
3758 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3759</pre>
3760
3761<h5>Overview:</h5>
3762<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
3763integer and converts that value to the <tt>ty2</tt> type.</p>
3764
3765<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3766<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3767scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3768to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3769type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3770floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3771
3772<h5>Semantics:</h5>
3773<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
3774integer quantity and converts it to the corresponding floating point value. If
3775the value cannot fit in the floating point value, the results are undefined.</p>
3776
3777<h5>Example:</h5>
3778<pre>
3779 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3780 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3781</pre>
3782</div>
3783
3784<!-- _______________________________________________________________________ -->
3785<div class="doc_subsubsection">
3786 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3787</div>
3788<div class="doc_text">
3789
3790<h5>Syntax:</h5>
3791<pre>
3792 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3793</pre>
3794
3795<h5>Overview:</h5>
3796<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3797the integer type <tt>ty2</tt>.</p>
3798
3799<h5>Arguments:</h5>
3800<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3801must 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]3802<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]3803
3804<h5>Semantics:</h5>
3805<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3806<tt>ty2</tt> by interpreting the pointer value as an integer and either
3807truncating or zero extending that value to the size of the integer type. If
3808<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3809<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3810are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3811change.</p>
3812
3813<h5>Example:</h5>
3814<pre>
3815 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3816 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
3817</pre>
3818</div>
3819
3820<!-- _______________________________________________________________________ -->
3821<div class="doc_subsubsection">
3822 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3823</div>
3824<div class="doc_text">
3825
3826<h5>Syntax:</h5>
3827<pre>
3828 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3829</pre>
3830
3831<h5>Overview:</h5>
3832<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3833a pointer type, <tt>ty2</tt>.</p>
3834
3835<h5>Arguments:</h5>
3836<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
3837value to cast, and a type to cast it to, which must be a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3838<a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3839
3840<h5>Semantics:</h5>
3841<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3842<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3843the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3844size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3845the size of a pointer then a zero extension is done. If they are the same size,
3846nothing is done (<i>no-op cast</i>).</p>
3847
3848<h5>Example:</h5>
3849<pre>
3850 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3851 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3852 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
3853</pre>
3854</div>
3855
3856<!-- _______________________________________________________________________ -->
3857<div class="doc_subsubsection">
3858 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
3859</div>
3860<div class="doc_text">
3861
3862<h5>Syntax:</h5>
3863<pre>
3864 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3865</pre>
3866
3867<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3868
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3869<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
3870<tt>ty2</tt> without changing any bits.</p>
3871
3872<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3873
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3874<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Dan Gohman7305fa02008-09-08 16:45:59 +0000[diff] [blame]3875a non-aggregate first class value, and a type to cast it to, which must also be
3876a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
3877<tt>value</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3878and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3879type is a pointer, the destination type must also be a pointer. This
3880instruction supports bitwise conversion of vectors to integers and to vectors
3881of other types (as long as they have the same size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3882
3883<h5>Semantics:</h5>
3884<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
3885<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3886this conversion. The conversion is done as if the <tt>value</tt> had been
3887stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3888converted to other pointer types with this instruction. To convert pointers to
3889other types, use the <a href="#i_inttoptr">inttoptr</a> or
3890<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
3891
3892<h5>Example:</h5>
3893<pre>
3894 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
3895 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3896 %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]3897</pre>
3898</div>
3899
3900<!-- ======================================================================= -->
3901<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3902<div class="doc_text">
3903<p>The instructions in this category are the "miscellaneous"
3904instructions, which defy better classification.</p>
3905</div>
3906
3907<!-- _______________________________________________________________________ -->
3908<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3909</div>
3910<div class="doc_text">
3911<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3912<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]3913</pre>
3914<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]3915<p>The '<tt>icmp</tt>' instruction returns a boolean value or
3916a vector of boolean values based on comparison
3917of its two integer, integer vector, or pointer operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3918<h5>Arguments:</h5>
3919<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
3920the condition code indicating the kind of comparison to perform. It is not
3921a value, just a keyword. The possible condition code are:
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3922</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3923<ol>
3924 <li><tt>eq</tt>: equal</li>
3925 <li><tt>ne</tt>: not equal </li>
3926 <li><tt>ugt</tt>: unsigned greater than</li>
3927 <li><tt>uge</tt>: unsigned greater or equal</li>
3928 <li><tt>ult</tt>: unsigned less than</li>
3929 <li><tt>ule</tt>: unsigned less or equal</li>
3930 <li><tt>sgt</tt>: signed greater than</li>
3931 <li><tt>sge</tt>: signed greater or equal</li>
3932 <li><tt>slt</tt>: signed less than</li>
3933 <li><tt>sle</tt>: signed less or equal</li>
3934</ol>
3935<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]3936<a href="#t_pointer">pointer</a>
3937or integer <a href="#t_vector">vector</a> typed.
3938They must also be identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3939<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3940<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]3941the condition code given as <tt>cond</tt>. The comparison performed always
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]3942yields 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]3943</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3944<ol>
3945 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3946 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3947 </li>
3948 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3949 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3950 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3951 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3952 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3953 <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]3954 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3955 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3956 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3957 <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]3958 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3959 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3960 <li><tt>sge</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3961 <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]3962 <li><tt>slt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3963 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3964 <li><tt>sle</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3965 <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]3966</ol>
3967<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
3968values are compared as if they were integers.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]3969<p>If the operands are integer vectors, then they are compared
3970element by element. The result is an <tt>i1</tt> vector with
3971the same number of elements as the values being compared.
3972Otherwise, the result is an <tt>i1</tt>.
3973</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3974
3975<h5>Example:</h5>
3976<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3977 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3978 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3979 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3980 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3981 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
3982</pre>
3983</div>
3984
3985<!-- _______________________________________________________________________ -->
3986<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3987</div>
3988<div class="doc_text">
3989<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3990<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]3991</pre>
3992<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]3993<p>The '<tt>fcmp</tt>' instruction returns a boolean value
3994or vector of boolean values based on comparison
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3995of its operands.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]3996<p>
3997If the operands are floating point scalars, then the result
3998type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
3999</p>
4000<p>If the operands are floating point vectors, then the result type
4001is a vector of boolean with the same number of elements as the
4002operands being compared.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4003<h5>Arguments:</h5>
4004<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
4005the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4006a value, just a keyword. The possible condition code are:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4007<ol>
4008 <li><tt>false</tt>: no comparison, always returns false</li>
4009 <li><tt>oeq</tt>: ordered and equal</li>
4010 <li><tt>ogt</tt>: ordered and greater than </li>
4011 <li><tt>oge</tt>: ordered and greater than or equal</li>
4012 <li><tt>olt</tt>: ordered and less than </li>
4013 <li><tt>ole</tt>: ordered and less than or equal</li>
4014 <li><tt>one</tt>: ordered and not equal</li>
4015 <li><tt>ord</tt>: ordered (no nans)</li>
4016 <li><tt>ueq</tt>: unordered or equal</li>
4017 <li><tt>ugt</tt>: unordered or greater than </li>
4018 <li><tt>uge</tt>: unordered or greater than or equal</li>
4019 <li><tt>ult</tt>: unordered or less than </li>
4020 <li><tt>ule</tt>: unordered or less than or equal</li>
4021 <li><tt>une</tt>: unordered or not equal</li>
4022 <li><tt>uno</tt>: unordered (either nans)</li>
4023 <li><tt>true</tt>: no comparison, always returns true</li>
4024</ol>
4025<p><i>Ordered</i> means that neither operand is a QNAN while
4026<i>unordered</i> means that either operand may be a QNAN.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4027<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
4028either a <a href="#t_floating">floating point</a> type
4029or a <a href="#t_vector">vector</a> of floating point type.
4030They must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4031<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4032<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4033according to the condition code given as <tt>cond</tt>.
4034If the operands are vectors, then the vectors are compared
4035element by element.
4036Each comparison performed
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4037always yields an <a href="#t_primitive">i1</a> result, as follows:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4038<ol>
4039 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
4040 <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]4041 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4042 <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]4043 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4044 <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]4045 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4046 <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]4047 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4048 <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]4049 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4050 <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]4051 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4052 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
4053 <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]4054 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4055 <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]4056 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4057 <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]4058 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4059 <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]4060 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4061 <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]4062 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4063 <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]4064 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4065 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
4066 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4067</ol>
4068
4069<h5>Example:</h5>
4070<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]4071 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4072 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4073 &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]4074</pre>
4075</div>
4076
4077<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4078<div class="doc_subsubsection">
4079 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
4080</div>
4081<div class="doc_text">
4082<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4083<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]4084</pre>
4085<h5>Overview:</h5>
4086<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
4087element-wise comparison of its two integer vector operands.</p>
4088<h5>Arguments:</h5>
4089<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
4090the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4091a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4092<ol>
4093 <li><tt>eq</tt>: equal</li>
4094 <li><tt>ne</tt>: not equal </li>
4095 <li><tt>ugt</tt>: unsigned greater than</li>
4096 <li><tt>uge</tt>: unsigned greater or equal</li>
4097 <li><tt>ult</tt>: unsigned less than</li>
4098 <li><tt>ule</tt>: unsigned less or equal</li>
4099 <li><tt>sgt</tt>: signed greater than</li>
4100 <li><tt>sge</tt>: signed greater or equal</li>
4101 <li><tt>slt</tt>: signed less than</li>
4102 <li><tt>sle</tt>: signed less or equal</li>
4103</ol>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4104<p>The remaining two arguments must be <a href="#t_vector">vector</a> or
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4105<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
4106<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4107<p>The '<tt>vicmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4108according to the condition code given as <tt>cond</tt>. The comparison yields a
4109<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
4110identical type as the values being compared. The most significant bit in each
4111element is 1 if the element-wise comparison evaluates to true, and is 0
4112otherwise. All other bits of the result are undefined. The condition codes
4113are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4114instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4115
4116<h5>Example:</h5>
4117<pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4118 &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>
4119 &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]4120</pre>
4121</div>
4122
4123<!-- _______________________________________________________________________ -->
4124<div class="doc_subsubsection">
4125 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
4126</div>
4127<div class="doc_text">
4128<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4129<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]4130<h5>Overview:</h5>
4131<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
4132element-wise comparison of its two floating point vector operands. The output
4133elements have the same width as the input elements.</p>
4134<h5>Arguments:</h5>
4135<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
4136the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4137a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4138<ol>
4139 <li><tt>false</tt>: no comparison, always returns false</li>
4140 <li><tt>oeq</tt>: ordered and equal</li>
4141 <li><tt>ogt</tt>: ordered and greater than </li>
4142 <li><tt>oge</tt>: ordered and greater than or equal</li>
4143 <li><tt>olt</tt>: ordered and less than </li>
4144 <li><tt>ole</tt>: ordered and less than or equal</li>
4145 <li><tt>one</tt>: ordered and not equal</li>
4146 <li><tt>ord</tt>: ordered (no nans)</li>
4147 <li><tt>ueq</tt>: unordered or equal</li>
4148 <li><tt>ugt</tt>: unordered or greater than </li>
4149 <li><tt>uge</tt>: unordered or greater than or equal</li>
4150 <li><tt>ult</tt>: unordered or less than </li>
4151 <li><tt>ule</tt>: unordered or less than or equal</li>
4152 <li><tt>une</tt>: unordered or not equal</li>
4153 <li><tt>uno</tt>: unordered (either nans)</li>
4154 <li><tt>true</tt>: no comparison, always returns true</li>
4155</ol>
4156<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4157<a href="#t_floating">floating point</a> typed. They must also be identical
4158types.</p>
4159<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4160<p>The '<tt>vfcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4161according to the condition code given as <tt>cond</tt>. The comparison yields a
4162<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4163an identical number of elements as the values being compared, and each element
4164having identical with to the width of the floating point elements. The most
4165significant bit in each element is 1 if the element-wise comparison evaluates to
4166true, and is 0 otherwise. All other bits of the result are undefined. The
4167condition codes are evaluated identically to the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4168<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4169
4170<h5>Example:</h5>
4171<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]4172 <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4173 &lt;result&gt; = vfcmp oeq &lt;2 x float&gt; &lt; float 4, float 0 &gt;, &lt; float 5, float 0 &gt;
4174
4175 <i>; yields: result=&lt;2 x i64&gt; &lt; i64 -1, i64 0 &gt;</i>
4176 &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]4177</pre>
4178</div>
4179
4180<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4181<div class="doc_subsubsection">
4182 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4183</div>
4184
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4185<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4186
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4187<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4188
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4189<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4190<h5>Overview:</h5>
4191<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4192the SSA graph representing the function.</p>
4193<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4194
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4195<p>The type of the incoming values is specified with the first type
4196field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4197as arguments, with one pair for each predecessor basic block of the
4198current block. Only values of <a href="#t_firstclass">first class</a>
4199type may be used as the value arguments to the PHI node. Only labels
4200may be used as the label arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4201
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4202<p>There must be no non-phi instructions between the start of a basic
4203block and the PHI instructions: i.e. PHI instructions must be first in
4204a basic block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4205
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4206<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4207
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4208<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4209specified by the pair corresponding to the predecessor basic block that executed
4210just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4211
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4212<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4213<pre>
4214Loop: ; Infinite loop that counts from 0 on up...
4215 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4216 %nextindvar = add i32 %indvar, 1
4217 br label %Loop
4218</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4219</div>
4220
4221<!-- _______________________________________________________________________ -->
4222<div class="doc_subsubsection">
4223 <a name="i_select">'<tt>select</tt>' Instruction</a>
4224</div>
4225
4226<div class="doc_text">
4227
4228<h5>Syntax:</h5>
4229
4230<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4231 &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>
4232
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4233 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4234</pre>
4235
4236<h5>Overview:</h5>
4237
4238<p>
4239The '<tt>select</tt>' instruction is used to choose one value based on a
4240condition, without branching.
4241</p>
4242
4243
4244<h5>Arguments:</h5>
4245
4246<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4247The '<tt>select</tt>' instruction requires an 'i1' value or
4248a vector of 'i1' values indicating the
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4249condition, and two values of the same <a href="#t_firstclass">first class</a>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4250type. If the val1/val2 are vectors and
4251the condition is a scalar, then entire vectors are selected, not
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4252individual elements.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4253</p>
4254
4255<h5>Semantics:</h5>
4256
4257<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4258If 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]4259value argument; otherwise, it returns the second value argument.
4260</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4261<p>
4262If the condition is a vector of i1, then the value arguments must
4263be vectors of the same size, and the selection is done element
4264by element.
4265</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4266
4267<h5>Example:</h5>
4268
4269<pre>
4270 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4271</pre>
4272</div>
4273
4274
4275<!-- _______________________________________________________________________ -->
4276<div class="doc_subsubsection">
4277 <a name="i_call">'<tt>call</tt>' Instruction</a>
4278</div>
4279
4280<div class="doc_text">
4281
4282<h5>Syntax:</h5>
4283<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4284 &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]4285</pre>
4286
4287<h5>Overview:</h5>
4288
4289<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4290
4291<h5>Arguments:</h5>
4292
4293<p>This instruction requires several arguments:</p>
4294
4295<ol>
4296 <li>
4297 <p>The optional "tail" marker indicates whether the callee function accesses
4298 any allocas or varargs in the caller. If the "tail" marker is present, the
4299 function call is eligible for tail call optimization. Note that calls may
4300 be marked "tail" even if they do not occur before a <a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4301 href="#i_ret"><tt>ret</tt></a> instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4302 </li>
4303 <li>
4304 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
4305 convention</a> the call should use. If none is specified, the call defaults
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4306 to using C calling conventions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4307 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4308
4309 <li>
4310 <p>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4311 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
4312 and '<tt>inreg</tt>' attributes are valid here.</p>
4313 </li>
4314
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4315 <li>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4316 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4317 the type of the return value. Functions that return no value are marked
4318 <tt><a href="#t_void">void</a></tt>.</p>
4319 </li>
4320 <li>
4321 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4322 value being invoked. The argument types must match the types implied by
4323 this signature. This type can be omitted if the function is not varargs
4324 and if the function type does not return a pointer to a function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4325 </li>
4326 <li>
4327 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4328 be invoked. In most cases, this is a direct function invocation, but
4329 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4330 to function value.</p>
4331 </li>
4332 <li>
4333 <p>'<tt>function args</tt>': argument list whose types match the
4334 function signature argument types. All arguments must be of
4335 <a href="#t_firstclass">first class</a> type. If the function signature
4336 indicates the function accepts a variable number of arguments, the extra
4337 arguments can be specified.</p>
4338 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4339 <li>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4340 <p>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4341 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4342 '<tt>readnone</tt>' attributes are valid here.</p>
4343 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4344</ol>
4345
4346<h5>Semantics:</h5>
4347
4348<p>The '<tt>call</tt>' instruction is used to cause control flow to
4349transfer to a specified function, with its incoming arguments bound to
4350the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4351instruction in the called function, control flow continues with the
4352instruction after the function call, and the return value of the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4353function is bound to the result argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4354
4355<h5>Example:</h5>
4356
4357<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4358 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4359 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4360 %X = tail call i32 @foo() <i>; yields i32</i>
4361 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4362 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4363
4364 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4365 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]4366 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4367 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]4368 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]4369 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4370</pre>
4371
4372</div>
4373
4374<!-- _______________________________________________________________________ -->
4375<div class="doc_subsubsection">
4376 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4377</div>
4378
4379<div class="doc_text">
4380
4381<h5>Syntax:</h5>
4382
4383<pre>
4384 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4385</pre>
4386
4387<h5>Overview:</h5>
4388
4389<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
4390the "variable argument" area of a function call. It is used to implement the
4391<tt>va_arg</tt> macro in C.</p>
4392
4393<h5>Arguments:</h5>
4394
4395<p>This instruction takes a <tt>va_list*</tt> value and the type of
4396the argument. It returns a value of the specified argument type and
4397increments the <tt>va_list</tt> to point to the next argument. The
4398actual type of <tt>va_list</tt> is target specific.</p>
4399
4400<h5>Semantics:</h5>
4401
4402<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4403type from the specified <tt>va_list</tt> and causes the
4404<tt>va_list</tt> to point to the next argument. For more information,
4405see the variable argument handling <a href="#int_varargs">Intrinsic
4406Functions</a>.</p>
4407
4408<p>It is legal for this instruction to be called in a function which does not
4409take a variable number of arguments, for example, the <tt>vfprintf</tt>
4410function.</p>
4411
4412<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
4413href="#intrinsics">intrinsic function</a> because it takes a type as an
4414argument.</p>
4415
4416<h5>Example:</h5>
4417
4418<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4419
4420</div>
4421
4422<!-- *********************************************************************** -->
4423<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4424<!-- *********************************************************************** -->
4425
4426<div class="doc_text">
4427
4428<p>LLVM supports the notion of an "intrinsic function". These functions have
4429well known names and semantics and are required to follow certain restrictions.
4430Overall, these intrinsics represent an extension mechanism for the LLVM
4431language that does not require changing all of the transformations in LLVM when
4432adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
4433
4434<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
4435prefix is reserved in LLVM for intrinsic names; thus, function names may not
4436begin with this prefix. Intrinsic functions must always be external functions:
4437you cannot define the body of intrinsic functions. Intrinsic functions may
4438only be used in call or invoke instructions: it is illegal to take the address
4439of an intrinsic function. Additionally, because intrinsic functions are part
4440of the LLVM language, it is required if any are added that they be documented
4441here.</p>
4442
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4443<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4444a family of functions that perform the same operation but on different data
4445types. Because LLVM can represent over 8 million different integer types,
4446overloading is used commonly to allow an intrinsic function to operate on any
4447integer type. One or more of the argument types or the result type can be
4448overloaded to accept any integer type. Argument types may also be defined as
4449exactly matching a previous argument's type or the result type. This allows an
4450intrinsic function which accepts multiple arguments, but needs all of them to
4451be of the same type, to only be overloaded with respect to a single argument or
4452the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4453
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4454<p>Overloaded intrinsics will have the names of its overloaded argument types
4455encoded into its function name, each preceded by a period. Only those types
4456which are overloaded result in a name suffix. Arguments whose type is matched
4457against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4458take an integer of any width and returns an integer of exactly the same integer
4459width. This leads to a family of functions such as
4460<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4461Only one type, the return type, is overloaded, and only one type suffix is
4462required. Because the argument's type is matched against the return type, it
4463does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4464
4465<p>To learn how to add an intrinsic function, please see the
4466<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
4467</p>
4468
4469</div>
4470
4471<!-- ======================================================================= -->
4472<div class="doc_subsection">
4473 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4474</div>
4475
4476<div class="doc_text">
4477
4478<p>Variable argument support is defined in LLVM with the <a
4479 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4480intrinsic functions. These functions are related to the similarly
4481named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
4482
4483<p>All of these functions operate on arguments that use a
4484target-specific value type "<tt>va_list</tt>". The LLVM assembly
4485language reference manual does not define what this type is, so all
4486transformations should be prepared to handle these functions regardless of
4487the type used.</p>
4488
4489<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
4490instruction and the variable argument handling intrinsic functions are
4491used.</p>
4492
4493<div class="doc_code">
4494<pre>
4495define i32 @test(i32 %X, ...) {
4496 ; Initialize variable argument processing
4497 %ap = alloca i8*
4498 %ap2 = bitcast i8** %ap to i8*
4499 call void @llvm.va_start(i8* %ap2)
4500
4501 ; Read a single integer argument
4502 %tmp = va_arg i8** %ap, i32
4503
4504 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4505 %aq = alloca i8*
4506 %aq2 = bitcast i8** %aq to i8*
4507 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4508 call void @llvm.va_end(i8* %aq2)
4509
4510 ; Stop processing of arguments.
4511 call void @llvm.va_end(i8* %ap2)
4512 ret i32 %tmp
4513}
4514
4515declare void @llvm.va_start(i8*)
4516declare void @llvm.va_copy(i8*, i8*)
4517declare void @llvm.va_end(i8*)
4518</pre>
4519</div>
4520
4521</div>
4522
4523<!-- _______________________________________________________________________ -->
4524<div class="doc_subsubsection">
4525 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4526</div>
4527
4528
4529<div class="doc_text">
4530<h5>Syntax:</h5>
4531<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
4532<h5>Overview:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4533<p>The '<tt>llvm.va_start</tt>' intrinsic initializes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4534<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4535href="#i_va_arg">va_arg</a></tt>.</p>
4536
4537<h5>Arguments:</h5>
4538
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4539<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]4540
4541<h5>Semantics:</h5>
4542
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4543<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]4544macro available in C. In a target-dependent way, it initializes the
4545<tt>va_list</tt> element to which the argument points, so that the next call to
4546<tt>va_arg</tt> will produce the first variable argument passed to the function.
4547Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
4548last argument of the function as the compiler can figure that out.</p>
4549
4550</div>
4551
4552<!-- _______________________________________________________________________ -->
4553<div class="doc_subsubsection">
4554 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
4555</div>
4556
4557<div class="doc_text">
4558<h5>Syntax:</h5>
4559<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
4560<h5>Overview:</h5>
4561
4562<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
4563which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
4564or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
4565
4566<h5>Arguments:</h5>
4567
4568<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
4569
4570<h5>Semantics:</h5>
4571
4572<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
4573macro available in C. In a target-dependent way, it destroys the
4574<tt>va_list</tt> element to which the argument points. Calls to <a
4575href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4576<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4577<tt>llvm.va_end</tt>.</p>
4578
4579</div>
4580
4581<!-- _______________________________________________________________________ -->
4582<div class="doc_subsubsection">
4583 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
4584</div>
4585
4586<div class="doc_text">
4587
4588<h5>Syntax:</h5>
4589
4590<pre>
4591 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
4592</pre>
4593
4594<h5>Overview:</h5>
4595
4596<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4597from the source argument list to the destination argument list.</p>
4598
4599<h5>Arguments:</h5>
4600
4601<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
4602The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
4603
4604
4605<h5>Semantics:</h5>
4606
4607<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4608macro available in C. In a target-dependent way, it copies the source
4609<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4610intrinsic is necessary because the <tt><a href="#int_va_start">
4611llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4612example, memory allocation.</p>
4613
4614</div>
4615
4616<!-- ======================================================================= -->
4617<div class="doc_subsection">
4618 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4619</div>
4620
4621<div class="doc_text">
4622
4623<p>
4624LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]4625Collection</a> (GC) requires the implementation and generation of these
4626intrinsics.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4627These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
4628stack</a>, as well as garbage collector implementations that require <a
4629href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
4630Front-ends for type-safe garbage collected languages should generate these
4631intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4632href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4633</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]4634
4635<p>The garbage collection intrinsics only operate on objects in the generic
4636 address space (address space zero).</p>
4637
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4638</div>
4639
4640<!-- _______________________________________________________________________ -->
4641<div class="doc_subsubsection">
4642 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
4643</div>
4644
4645<div class="doc_text">
4646
4647<h5>Syntax:</h5>
4648
4649<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4650 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4651</pre>
4652
4653<h5>Overview:</h5>
4654
4655<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
4656the code generator, and allows some metadata to be associated with it.</p>
4657
4658<h5>Arguments:</h5>
4659
4660<p>The first argument specifies the address of a stack object that contains the
4661root pointer. The second pointer (which must be either a constant or a global
4662value address) contains the meta-data to be associated with the root.</p>
4663
4664<h5>Semantics:</h5>
4665
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]4666<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]4667location. At compile-time, the code generator generates information to allow
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4668the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4669intrinsic may only be used in a function which <a href="#gc">specifies a GC
4670algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4671
4672</div>
4673
4674
4675<!-- _______________________________________________________________________ -->
4676<div class="doc_subsubsection">
4677 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
4678</div>
4679
4680<div class="doc_text">
4681
4682<h5>Syntax:</h5>
4683
4684<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4685 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4686</pre>
4687
4688<h5>Overview:</h5>
4689
4690<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4691locations, allowing garbage collector implementations that require read
4692barriers.</p>
4693
4694<h5>Arguments:</h5>
4695
4696<p>The second argument is the address to read from, which should be an address
4697allocated from the garbage collector. The first object is a pointer to the
4698start of the referenced object, if needed by the language runtime (otherwise
4699null).</p>
4700
4701<h5>Semantics:</h5>
4702
4703<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4704instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4705garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4706may only be used in a function which <a href="#gc">specifies a GC
4707algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4708
4709</div>
4710
4711
4712<!-- _______________________________________________________________________ -->
4713<div class="doc_subsubsection">
4714 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
4715</div>
4716
4717<div class="doc_text">
4718
4719<h5>Syntax:</h5>
4720
4721<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4722 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4723</pre>
4724
4725<h5>Overview:</h5>
4726
4727<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4728locations, allowing garbage collector implementations that require write
4729barriers (such as generational or reference counting collectors).</p>
4730
4731<h5>Arguments:</h5>
4732
4733<p>The first argument is the reference to store, the second is the start of the
4734object to store it to, and the third is the address of the field of Obj to
4735store to. If the runtime does not require a pointer to the object, Obj may be
4736null.</p>
4737
4738<h5>Semantics:</h5>
4739
4740<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4741instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4742garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4743may only be used in a function which <a href="#gc">specifies a GC
4744algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4745
4746</div>
4747
4748
4749
4750<!-- ======================================================================= -->
4751<div class="doc_subsection">
4752 <a name="int_codegen">Code Generator Intrinsics</a>
4753</div>
4754
4755<div class="doc_text">
4756<p>
4757These intrinsics are provided by LLVM to expose special features that may only
4758be implemented with code generator support.
4759</p>
4760
4761</div>
4762
4763<!-- _______________________________________________________________________ -->
4764<div class="doc_subsubsection">
4765 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
4766</div>
4767
4768<div class="doc_text">
4769
4770<h5>Syntax:</h5>
4771<pre>
4772 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
4773</pre>
4774
4775<h5>Overview:</h5>
4776
4777<p>
4778The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4779target-specific value indicating the return address of the current function
4780or one of its callers.
4781</p>
4782
4783<h5>Arguments:</h5>
4784
4785<p>
4786The argument to this intrinsic indicates which function to return the address
4787for. Zero indicates the calling function, one indicates its caller, etc. The
4788argument is <b>required</b> to be a constant integer value.
4789</p>
4790
4791<h5>Semantics:</h5>
4792
4793<p>
4794The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4795the return address of the specified call frame, or zero if it cannot be
4796identified. The value returned by this intrinsic is likely to be incorrect or 0
4797for arguments other than zero, so it should only be used for debugging purposes.
4798</p>
4799
4800<p>
4801Note that calling this intrinsic does not prevent function inlining or other
4802aggressive transformations, so the value returned may not be that of the obvious
4803source-language caller.
4804</p>
4805</div>
4806
4807
4808<!-- _______________________________________________________________________ -->
4809<div class="doc_subsubsection">
4810 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
4811</div>
4812
4813<div class="doc_text">
4814
4815<h5>Syntax:</h5>
4816<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4817 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4818</pre>
4819
4820<h5>Overview:</h5>
4821
4822<p>
4823The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4824target-specific frame pointer value for the specified stack frame.
4825</p>
4826
4827<h5>Arguments:</h5>
4828
4829<p>
4830The argument to this intrinsic indicates which function to return the frame
4831pointer for. Zero indicates the calling function, one indicates its caller,
4832etc. The argument is <b>required</b> to be a constant integer value.
4833</p>
4834
4835<h5>Semantics:</h5>
4836
4837<p>
4838The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4839the frame address of the specified call frame, or zero if it cannot be
4840identified. The value returned by this intrinsic is likely to be incorrect or 0
4841for arguments other than zero, so it should only be used for debugging purposes.
4842</p>
4843
4844<p>
4845Note that calling this intrinsic does not prevent function inlining or other
4846aggressive transformations, so the value returned may not be that of the obvious
4847source-language caller.
4848</p>
4849</div>
4850
4851<!-- _______________________________________________________________________ -->
4852<div class="doc_subsubsection">
4853 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
4854</div>
4855
4856<div class="doc_text">
4857
4858<h5>Syntax:</h5>
4859<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4860 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4861</pre>
4862
4863<h5>Overview:</h5>
4864
4865<p>
4866The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
4867the function stack, for use with <a href="#int_stackrestore">
4868<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4869features like scoped automatic variable sized arrays in C99.
4870</p>
4871
4872<h5>Semantics:</h5>
4873
4874<p>
4875This intrinsic returns a opaque pointer value that can be passed to <a
4876href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
4877<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4878<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4879state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4880practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4881that were allocated after the <tt>llvm.stacksave</tt> was executed.
4882</p>
4883
4884</div>
4885
4886<!-- _______________________________________________________________________ -->
4887<div class="doc_subsubsection">
4888 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
4889</div>
4890
4891<div class="doc_text">
4892
4893<h5>Syntax:</h5>
4894<pre>
4895 declare void @llvm.stackrestore(i8 * %ptr)
4896</pre>
4897
4898<h5>Overview:</h5>
4899
4900<p>
4901The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4902the function stack to the state it was in when the corresponding <a
4903href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
4904useful for implementing language features like scoped automatic variable sized
4905arrays in C99.
4906</p>
4907
4908<h5>Semantics:</h5>
4909
4910<p>
4911See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
4912</p>
4913
4914</div>
4915
4916
4917<!-- _______________________________________________________________________ -->
4918<div class="doc_subsubsection">
4919 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
4920</div>
4921
4922<div class="doc_text">
4923
4924<h5>Syntax:</h5>
4925<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4926 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]4927</pre>
4928
4929<h5>Overview:</h5>
4930
4931
4932<p>
4933The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
4934a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4935no
4936effect on the behavior of the program but can change its performance
4937characteristics.
4938</p>
4939
4940<h5>Arguments:</h5>
4941
4942<p>
4943<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4944determining if the fetch should be for a read (0) or write (1), and
4945<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
4946locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
4947<tt>locality</tt> arguments must be constant integers.
4948</p>
4949
4950<h5>Semantics:</h5>
4951
4952<p>
4953This intrinsic does not modify the behavior of the program. In particular,
4954prefetches cannot trap and do not produce a value. On targets that support this
4955intrinsic, the prefetch can provide hints to the processor cache for better
4956performance.
4957</p>
4958
4959</div>
4960
4961<!-- _______________________________________________________________________ -->
4962<div class="doc_subsubsection">
4963 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
4964</div>
4965
4966<div class="doc_text">
4967
4968<h5>Syntax:</h5>
4969<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4970 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4971</pre>
4972
4973<h5>Overview:</h5>
4974
4975
4976<p>
4977The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]4978(PC) in a region of
4979code to simulators and other tools. The method is target specific, but it is
4980expected that the marker will use exported symbols to transmit the PC of the
4981marker.
4982The marker makes no guarantees that it will remain with any specific instruction
4983after optimizations. It is possible that the presence of a marker will inhibit
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4984optimizations. The intended use is to be inserted after optimizations to allow
4985correlations of simulation runs.
4986</p>
4987
4988<h5>Arguments:</h5>
4989
4990<p>
4991<tt>id</tt> is a numerical id identifying the marker.
4992</p>
4993
4994<h5>Semantics:</h5>
4995
4996<p>
4997This intrinsic does not modify the behavior of the program. Backends that do not
4998support this intrinisic may ignore it.
4999</p>
5000
5001</div>
5002
5003<!-- _______________________________________________________________________ -->
5004<div class="doc_subsubsection">
5005 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5006</div>
5007
5008<div class="doc_text">
5009
5010<h5>Syntax:</h5>
5011<pre>
5012 declare i64 @llvm.readcyclecounter( )
5013</pre>
5014
5015<h5>Overview:</h5>
5016
5017
5018<p>
5019The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5020counter register (or similar low latency, high accuracy clocks) on those targets
5021that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
5022As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
5023should only be used for small timings.
5024</p>
5025
5026<h5>Semantics:</h5>
5027
5028<p>
5029When directly supported, reading the cycle counter should not modify any memory.
5030Implementations are allowed to either return a application specific value or a
5031system wide value. On backends without support, this is lowered to a constant 0.
5032</p>
5033
5034</div>
5035
5036<!-- ======================================================================= -->
5037<div class="doc_subsection">
5038 <a name="int_libc">Standard C Library Intrinsics</a>
5039</div>
5040
5041<div class="doc_text">
5042<p>
5043LLVM provides intrinsics for a few important standard C library functions.
5044These intrinsics allow source-language front-ends to pass information about the
5045alignment of the pointer arguments to the code generator, providing opportunity
5046for more efficient code generation.
5047</p>
5048
5049</div>
5050
5051<!-- _______________________________________________________________________ -->
5052<div class="doc_subsubsection">
5053 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5054</div>
5055
5056<div class="doc_text">
5057
5058<h5>Syntax:</h5>
5059<pre>
5060 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5061 i32 &lt;len&gt;, i32 &lt;align&gt;)
5062 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5063 i64 &lt;len&gt;, i32 &lt;align&gt;)
5064</pre>
5065
5066<h5>Overview:</h5>
5067
5068<p>
5069The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5070location to the destination location.
5071</p>
5072
5073<p>
5074Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5075intrinsics do not return a value, and takes an extra alignment argument.
5076</p>
5077
5078<h5>Arguments:</h5>
5079
5080<p>
5081The first argument is a pointer to the destination, the second is a pointer to
5082the source. The third argument is an integer argument
5083specifying the number of bytes to copy, and the fourth argument is the alignment
5084of the source and destination locations.
5085</p>
5086
5087<p>
5088If the call to this intrinisic has an alignment value that is not 0 or 1, then
5089the caller guarantees that both the source and destination pointers are aligned
5090to that boundary.
5091</p>
5092
5093<h5>Semantics:</h5>
5094
5095<p>
5096The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5097location to the destination location, which are not allowed to overlap. It
5098copies "len" bytes of memory over. If the argument is known to be aligned to
5099some boundary, this can be specified as the fourth argument, otherwise it should
5100be set to 0 or 1.
5101</p>
5102</div>
5103
5104
5105<!-- _______________________________________________________________________ -->
5106<div class="doc_subsubsection">
5107 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5108</div>
5109
5110<div class="doc_text">
5111
5112<h5>Syntax:</h5>
5113<pre>
5114 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5115 i32 &lt;len&gt;, i32 &lt;align&gt;)
5116 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5117 i64 &lt;len&gt;, i32 &lt;align&gt;)
5118</pre>
5119
5120<h5>Overview:</h5>
5121
5122<p>
5123The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5124location to the destination location. It is similar to the
Chris Lattnerdba16ea2008-01-06 19:51:52 +0000[diff] [blame]5125'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5126</p>
5127
5128<p>
5129Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5130intrinsics do not return a value, and takes an extra alignment argument.
5131</p>
5132
5133<h5>Arguments:</h5>
5134
5135<p>
5136The first argument is a pointer to the destination, the second is a pointer to
5137the source. The third argument is an integer argument
5138specifying the number of bytes to copy, and the fourth argument is the alignment
5139of the source and destination locations.
5140</p>
5141
5142<p>
5143If the call to this intrinisic has an alignment value that is not 0 or 1, then
5144the caller guarantees that the source and destination pointers are aligned to
5145that boundary.
5146</p>
5147
5148<h5>Semantics:</h5>
5149
5150<p>
5151The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
5152location to the destination location, which may overlap. It
5153copies "len" bytes of memory over. If the argument is known to be aligned to
5154some boundary, this can be specified as the fourth argument, otherwise it should
5155be set to 0 or 1.
5156</p>
5157</div>
5158
5159
5160<!-- _______________________________________________________________________ -->
5161<div class="doc_subsubsection">
5162 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5163</div>
5164
5165<div class="doc_text">
5166
5167<h5>Syntax:</h5>
5168<pre>
5169 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5170 i32 &lt;len&gt;, i32 &lt;align&gt;)
5171 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5172 i64 &lt;len&gt;, i32 &lt;align&gt;)
5173</pre>
5174
5175<h5>Overview:</h5>
5176
5177<p>
5178The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
5179byte value.
5180</p>
5181
5182<p>
5183Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5184does not return a value, and takes an extra alignment argument.
5185</p>
5186
5187<h5>Arguments:</h5>
5188
5189<p>
5190The first argument is a pointer to the destination to fill, the second is the
5191byte value to fill it with, the third argument is an integer
5192argument specifying the number of bytes to fill, and the fourth argument is the
5193known alignment of destination location.
5194</p>
5195
5196<p>
5197If the call to this intrinisic has an alignment value that is not 0 or 1, then
5198the caller guarantees that the destination pointer is aligned to that boundary.
5199</p>
5200
5201<h5>Semantics:</h5>
5202
5203<p>
5204The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5205the
5206destination location. If the argument is known to be aligned to some boundary,
5207this can be specified as the fourth argument, otherwise it should be set to 0 or
52081.
5209</p>
5210</div>
5211
5212
5213<!-- _______________________________________________________________________ -->
5214<div class="doc_subsubsection">
5215 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5216</div>
5217
5218<div class="doc_text">
5219
5220<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5221<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]5222floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5223types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5224<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5225 declare float @llvm.sqrt.f32(float %Val)
5226 declare double @llvm.sqrt.f64(double %Val)
5227 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5228 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5229 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5230</pre>
5231
5232<h5>Overview:</h5>
5233
5234<p>
5235The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5236returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5237<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattnerf914a002008-01-29 07:00:44 +0000[diff] [blame]5238negative numbers other than -0.0 (which allows for better optimization, because
5239there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5240defined to return -0.0 like IEEE sqrt.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5241</p>
5242
5243<h5>Arguments:</h5>
5244
5245<p>
5246The argument and return value are floating point numbers of the same type.
5247</p>
5248
5249<h5>Semantics:</h5>
5250
5251<p>
5252This function returns the sqrt of the specified operand if it is a nonnegative
5253floating point number.
5254</p>
5255</div>
5256
5257<!-- _______________________________________________________________________ -->
5258<div class="doc_subsubsection">
5259 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5260</div>
5261
5262<div class="doc_text">
5263
5264<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5265<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]5266floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5267types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5268<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5269 declare float @llvm.powi.f32(float %Val, i32 %power)
5270 declare double @llvm.powi.f64(double %Val, i32 %power)
5271 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5272 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5273 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5274</pre>
5275
5276<h5>Overview:</h5>
5277
5278<p>
5279The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5280specified (positive or negative) power. The order of evaluation of
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5281multiplications is not defined. When a vector of floating point type is
5282used, the second argument remains a scalar integer value.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5283</p>
5284
5285<h5>Arguments:</h5>
5286
5287<p>
5288The second argument is an integer power, and the first is a value to raise to
5289that power.
5290</p>
5291
5292<h5>Semantics:</h5>
5293
5294<p>
5295This function returns the first value raised to the second power with an
5296unspecified sequence of rounding operations.</p>
5297</div>
5298
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5299<!-- _______________________________________________________________________ -->
5300<div class="doc_subsubsection">
5301 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5302</div>
5303
5304<div class="doc_text">
5305
5306<h5>Syntax:</h5>
5307<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5308floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5309types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5310<pre>
5311 declare float @llvm.sin.f32(float %Val)
5312 declare double @llvm.sin.f64(double %Val)
5313 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5314 declare fp128 @llvm.sin.f128(fp128 %Val)
5315 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5316</pre>
5317
5318<h5>Overview:</h5>
5319
5320<p>
5321The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5322</p>
5323
5324<h5>Arguments:</h5>
5325
5326<p>
5327The argument and return value are floating point numbers of the same type.
5328</p>
5329
5330<h5>Semantics:</h5>
5331
5332<p>
5333This function returns the sine of the specified operand, returning the
5334same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5335conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5336</div>
5337
5338<!-- _______________________________________________________________________ -->
5339<div class="doc_subsubsection">
5340 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5341</div>
5342
5343<div class="doc_text">
5344
5345<h5>Syntax:</h5>
5346<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
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 Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5349<pre>
5350 declare float @llvm.cos.f32(float %Val)
5351 declare double @llvm.cos.f64(double %Val)
5352 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5353 declare fp128 @llvm.cos.f128(fp128 %Val)
5354 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5355</pre>
5356
5357<h5>Overview:</h5>
5358
5359<p>
5360The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5361</p>
5362
5363<h5>Arguments:</h5>
5364
5365<p>
5366The argument and return value are floating point numbers of the same type.
5367</p>
5368
5369<h5>Semantics:</h5>
5370
5371<p>
5372This function returns the cosine of the specified operand, returning the
5373same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5374conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5375</div>
5376
5377<!-- _______________________________________________________________________ -->
5378<div class="doc_subsubsection">
5379 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5380</div>
5381
5382<div class="doc_text">
5383
5384<h5>Syntax:</h5>
5385<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5386floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5387types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5388<pre>
5389 declare float @llvm.pow.f32(float %Val, float %Power)
5390 declare double @llvm.pow.f64(double %Val, double %Power)
5391 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5392 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5393 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5394</pre>
5395
5396<h5>Overview:</h5>
5397
5398<p>
5399The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5400specified (positive or negative) power.
5401</p>
5402
5403<h5>Arguments:</h5>
5404
5405<p>
5406The second argument is a floating point power, and the first is a value to
5407raise to that power.
5408</p>
5409
5410<h5>Semantics:</h5>
5411
5412<p>
5413This function returns the first value raised to the second power,
5414returning the
5415same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5416conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5417</div>
5418
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5419
5420<!-- ======================================================================= -->
5421<div class="doc_subsection">
5422 <a name="int_manip">Bit Manipulation Intrinsics</a>
5423</div>
5424
5425<div class="doc_text">
5426<p>
5427LLVM provides intrinsics for a few important bit manipulation operations.
5428These allow efficient code generation for some algorithms.
5429</p>
5430
5431</div>
5432
5433<!-- _______________________________________________________________________ -->
5434<div class="doc_subsubsection">
5435 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5436</div>
5437
5438<div class="doc_text">
5439
5440<h5>Syntax:</h5>
5441<p>This is an overloaded intrinsic function. You can use bswap on any integer
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5442type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5443<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5444 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5445 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5446 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5447</pre>
5448
5449<h5>Overview:</h5>
5450
5451<p>
5452The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5453values with an even number of bytes (positive multiple of 16 bits). These are
5454useful for performing operations on data that is not in the target's native
5455byte order.
5456</p>
5457
5458<h5>Semantics:</h5>
5459
5460<p>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5461The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5462and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5463intrinsic returns an i32 value that has the four bytes of the input i32
5464swapped, 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]5465i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5466<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5467additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
5468</p>
5469
5470</div>
5471
5472<!-- _______________________________________________________________________ -->
5473<div class="doc_subsubsection">
5474 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5475</div>
5476
5477<div class="doc_text">
5478
5479<h5>Syntax:</h5>
5480<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]5481width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5482<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5483 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
5484 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5485 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5486 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5487 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5488</pre>
5489
5490<h5>Overview:</h5>
5491
5492<p>
5493The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5494value.
5495</p>
5496
5497<h5>Arguments:</h5>
5498
5499<p>
5500The only argument is the value to be counted. The argument may be of any
5501integer type. The return type must match the argument type.
5502</p>
5503
5504<h5>Semantics:</h5>
5505
5506<p>
5507The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5508</p>
5509</div>
5510
5511<!-- _______________________________________________________________________ -->
5512<div class="doc_subsubsection">
5513 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5514</div>
5515
5516<div class="doc_text">
5517
5518<h5>Syntax:</h5>
5519<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]5520integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5521<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5522 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5523 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5524 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5525 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5526 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5527</pre>
5528
5529<h5>Overview:</h5>
5530
5531<p>
5532The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5533leading zeros in a variable.
5534</p>
5535
5536<h5>Arguments:</h5>
5537
5538<p>
5539The only argument is the value to be counted. The argument may be of any
5540integer type. The return type must match the argument type.
5541</p>
5542
5543<h5>Semantics:</h5>
5544
5545<p>
5546The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5547in a variable. If the src == 0 then the result is the size in bits of the type
5548of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
5549</p>
5550</div>
5551
5552
5553
5554<!-- _______________________________________________________________________ -->
5555<div class="doc_subsubsection">
5556 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5557</div>
5558
5559<div class="doc_text">
5560
5561<h5>Syntax:</h5>
5562<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]5563integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5564<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5565 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5566 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5567 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5568 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5569 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5570</pre>
5571
5572<h5>Overview:</h5>
5573
5574<p>
5575The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5576trailing zeros.
5577</p>
5578
5579<h5>Arguments:</h5>
5580
5581<p>
5582The only argument is the value to be counted. The argument may be of any
5583integer type. The return type must match the argument type.
5584</p>
5585
5586<h5>Semantics:</h5>
5587
5588<p>
5589The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5590in a variable. If the src == 0 then the result is the size in bits of the type
5591of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5592</p>
5593</div>
5594
5595<!-- _______________________________________________________________________ -->
5596<div class="doc_subsubsection">
5597 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
5598</div>
5599
5600<div class="doc_text">
5601
5602<h5>Syntax:</h5>
5603<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5604on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5605<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5606 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5607 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5608</pre>
5609
5610<h5>Overview:</h5>
5611<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
5612range of bits from an integer value and returns them in the same bit width as
5613the original value.</p>
5614
5615<h5>Arguments:</h5>
5616<p>The first argument, <tt>%val</tt> and the result may be integer types of
5617any bit width but they must have the same bit width. The second and third
5618arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
5619
5620<h5>Semantics:</h5>
5621<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
5622of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5623<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5624operates in forward mode.</p>
5625<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5626right by <tt>%loBit</tt> bits and then ANDing it with a mask with
5627only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5628<ol>
5629 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5630 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5631 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5632 to determine the number of bits to retain.</li>
5633 <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]5634 <li>The mask is ANDed with <tt>%val</tt> to produce the result.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5635</ol>
5636<p>In reverse mode, a similar computation is made except that the bits are
5637returned in the reverse order. So, for example, if <tt>X</tt> has the value
5638<tt>i16 0x0ACF (101011001111)</tt> and we apply
5639<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5640<tt>i16 0x0026 (000000100110)</tt>.</p>
5641</div>
5642
5643<div class="doc_subsubsection">
5644 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5645</div>
5646
5647<div class="doc_text">
5648
5649<h5>Syntax:</h5>
5650<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5651on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5652<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5653 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5654 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]5655</pre>
5656
5657<h5>Overview:</h5>
5658<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5659of bits in an integer value with another integer value. It returns the integer
5660with the replaced bits.</p>
5661
5662<h5>Arguments:</h5>
5663<p>The first argument, <tt>%val</tt> and the result may be integer types of
5664any bit width but they must have the same bit width. <tt>%val</tt> is the value
5665whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5666integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5667type since they specify only a bit index.</p>
5668
5669<h5>Semantics:</h5>
5670<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5671of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5672<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5673operates in forward mode.</p>
5674<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5675truncating it down to the size of the replacement area or zero extending it
5676up to that size.</p>
5677<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5678are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5679in <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]5680to the <tt>%hi</tt>th bit.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5681<p>In reverse mode, a similar computation is made except that the bits are
5682reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5683<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]5684<h5>Examples:</h5>
5685<pre>
5686 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
5687 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5688 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5689 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
5690 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
5691</pre>
5692</div>
5693
5694<!-- ======================================================================= -->
5695<div class="doc_subsection">
5696 <a name="int_debugger">Debugger Intrinsics</a>
5697</div>
5698
5699<div class="doc_text">
5700<p>
5701The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5702are described in the <a
5703href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5704Debugging</a> document.
5705</p>
5706</div>
5707
5708
5709<!-- ======================================================================= -->
5710<div class="doc_subsection">
5711 <a name="int_eh">Exception Handling Intrinsics</a>
5712</div>
5713
5714<div class="doc_text">
5715<p> The LLVM exception handling intrinsics (which all start with
5716<tt>llvm.eh.</tt> prefix), are described in the <a
5717href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5718Handling</a> document. </p>
5719</div>
5720
5721<!-- ======================================================================= -->
5722<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5723 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5724</div>
5725
5726<div class="doc_text">
5727<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5728 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5729 the <tt>nest</tt> attribute, from a function. The result is a callable
5730 function pointer lacking the nest parameter - the caller does not need
5731 to provide a value for it. Instead, the value to use is stored in
5732 advance in a "trampoline", a block of memory usually allocated
5733 on the stack, which also contains code to splice the nest value into the
5734 argument list. This is used to implement the GCC nested function address
5735 extension.
5736</p>
5737<p>
5738 For example, if the function is
5739 <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]5740 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]5741<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5742 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5743 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5744 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5745 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5746</pre>
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]5747 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5748 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5749</div>
5750
5751<!-- _______________________________________________________________________ -->
5752<div class="doc_subsubsection">
5753 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5754</div>
5755<div class="doc_text">
5756<h5>Syntax:</h5>
5757<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5758declare 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]5759</pre>
5760<h5>Overview:</h5>
5761<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5762 This fills the memory pointed to by <tt>tramp</tt> with code
5763 and returns a function pointer suitable for executing it.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5764</p>
5765<h5>Arguments:</h5>
5766<p>
5767 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5768 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5769 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sands35012212007-08-22 23:39:54 +0000[diff] [blame]5770 intrinsic. Note that the size and the alignment are target-specific - LLVM
5771 currently provides no portable way of determining them, so a front-end that
5772 generates this intrinsic needs to have some target-specific knowledge.
5773 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]5774</p>
5775<h5>Semantics:</h5>
5776<p>
5777 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5778 dependent code, turning it into a function. A pointer to this function is
5779 returned, but needs to be bitcast to an
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5780 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5781 before being called. The new function's signature is the same as that of
5782 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5783 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5784 of pointer type. Calling the new function is equivalent to calling
5785 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5786 missing <tt>nest</tt> argument. If, after calling
5787 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5788 modified, then the effect of any later call to the returned function pointer is
5789 undefined.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5790</p>
5791</div>
5792
5793<!-- ======================================================================= -->
5794<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5795 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
5796</div>
5797
5798<div class="doc_text">
5799<p>
5800 These intrinsic functions expand the "universal IR" of LLVM to represent
5801 hardware constructs for atomic operations and memory synchronization. This
5802 provides an interface to the hardware, not an interface to the programmer. It
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5803 is aimed at a low enough level to allow any programming models or APIs
5804 (Application Programming Interfaces) which
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5805 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
5806 hardware behavior. Just as hardware provides a "universal IR" for source
5807 languages, it also provides a starting point for developing a "universal"
5808 atomic operation and synchronization IR.
5809</p>
5810<p>
5811 These do <em>not</em> form an API such as high-level threading libraries,
5812 software transaction memory systems, atomic primitives, and intrinsic
5813 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
5814 application libraries. The hardware interface provided by LLVM should allow
5815 a clean implementation of all of these APIs and parallel programming models.
5816 No one model or paradigm should be selected above others unless the hardware
5817 itself ubiquitously does so.
5818
5819</p>
5820</div>
5821
5822<!-- _______________________________________________________________________ -->
5823<div class="doc_subsubsection">
5824 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5825</div>
5826<div class="doc_text">
5827<h5>Syntax:</h5>
5828<pre>
5829declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
5830i1 &lt;device&gt; )
5831
5832</pre>
5833<h5>Overview:</h5>
5834<p>
5835 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5836 specific pairs of memory access types.
5837</p>
5838<h5>Arguments:</h5>
5839<p>
5840 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
5841 The first four arguments enables a specific barrier as listed below. The fith
5842 argument specifies that the barrier applies to io or device or uncached memory.
5843
5844</p>
5845 <ul>
5846 <li><tt>ll</tt>: load-load barrier</li>
5847 <li><tt>ls</tt>: load-store barrier</li>
5848 <li><tt>sl</tt>: store-load barrier</li>
5849 <li><tt>ss</tt>: store-store barrier</li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5850 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5851 </ul>
5852<h5>Semantics:</h5>
5853<p>
5854 This intrinsic causes the system to enforce some ordering constraints upon
5855 the loads and stores of the program. This barrier does not indicate
5856 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5857 which they occur. For any of the specified pairs of load and store operations
5858 (f.ex. load-load, or store-load), all of the first operations preceding the
5859 barrier will complete before any of the second operations succeeding the
5860 barrier begin. Specifically the semantics for each pairing is as follows:
5861</p>
5862 <ul>
5863 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5864 after the barrier begins.</li>
5865
5866 <li><tt>ls</tt>: All loads before the barrier must complete before any
5867 store after the barrier begins.</li>
5868 <li><tt>ss</tt>: All stores before the barrier must complete before any
5869 store after the barrier begins.</li>
5870 <li><tt>sl</tt>: All stores before the barrier must complete before any
5871 load after the barrier begins.</li>
5872 </ul>
5873<p>
5874 These semantics are applied with a logical "and" behavior when more than one
5875 is enabled in a single memory barrier intrinsic.
5876</p>
5877<p>
5878 Backends may implement stronger barriers than those requested when they do not
5879 support as fine grained a barrier as requested. Some architectures do not
5880 need all types of barriers and on such architectures, these become noops.
5881</p>
5882<h5>Example:</h5>
5883<pre>
5884%ptr = malloc i32
5885 store i32 4, %ptr
5886
5887%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
5888 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
5889 <i>; guarantee the above finishes</i>
5890 store i32 8, %ptr <i>; before this begins</i>
5891</pre>
5892</div>
5893
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5894<!-- _______________________________________________________________________ -->
5895<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5896 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5897</div>
5898<div class="doc_text">
5899<h5>Syntax:</h5>
5900<p>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5901 This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
5902 any integer bit width and for different address spaces. Not all targets
5903 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5904
5905<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5906declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
5907declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
5908declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
5909declare 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]5910
5911</pre>
5912<h5>Overview:</h5>
5913<p>
5914 This loads a value in memory and compares it to a given value. If they are
5915 equal, it stores a new value into the memory.
5916</p>
5917<h5>Arguments:</h5>
5918<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5919 The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5920 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
5921 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
5922 this integer type. While any bit width integer may be used, targets may only
5923 lower representations they support in hardware.
5924
5925</p>
5926<h5>Semantics:</h5>
5927<p>
5928 This entire intrinsic must be executed atomically. It first loads the value
5929 in memory pointed to by <tt>ptr</tt> and compares it with the value
5930 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
5931 loaded value is yielded in all cases. This provides the equivalent of an
5932 atomic compare-and-swap operation within the SSA framework.
5933</p>
5934<h5>Examples:</h5>
5935
5936<pre>
5937%ptr = malloc i32
5938 store i32 4, %ptr
5939
5940%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5941%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5942 <i>; yields {i32}:result1 = 4</i>
5943%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5944%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5945
5946%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5947%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5948 <i>; yields {i32}:result2 = 8</i>
5949%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
5950
5951%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
5952</pre>
5953</div>
5954
5955<!-- _______________________________________________________________________ -->
5956<div class="doc_subsubsection">
5957 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
5958</div>
5959<div class="doc_text">
5960<h5>Syntax:</h5>
5961
5962<p>
5963 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
5964 integer bit width. Not all targets support all bit widths however.</p>
5965<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5966declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
5967declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
5968declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
5969declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5970
5971</pre>
5972<h5>Overview:</h5>
5973<p>
5974 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
5975 the value from memory. It then stores the value in <tt>val</tt> in the memory
5976 at <tt>ptr</tt>.
5977</p>
5978<h5>Arguments:</h5>
5979
5980<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5981 The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5982 <tt>val</tt> argument and the result must be integers of the same bit width.
5983 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
5984 integer type. The targets may only lower integer representations they
5985 support.
5986</p>
5987<h5>Semantics:</h5>
5988<p>
5989 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
5990 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
5991 equivalent of an atomic swap operation within the SSA framework.
5992
5993</p>
5994<h5>Examples:</h5>
5995<pre>
5996%ptr = malloc i32
5997 store i32 4, %ptr
5998
5999%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6000%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6001 <i>; yields {i32}:result1 = 4</i>
6002%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6003%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6004
6005%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6006%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6007 <i>; yields {i32}:result2 = 8</i>
6008
6009%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6010%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6011</pre>
6012</div>
6013
6014<!-- _______________________________________________________________________ -->
6015<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6016 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6017
6018</div>
6019<div class="doc_text">
6020<h5>Syntax:</h5>
6021<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6022 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]6023 integer bit width. Not all targets support all bit widths however.</p>
6024<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6025declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6026declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6027declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6028declare 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]6029
6030</pre>
6031<h5>Overview:</h5>
6032<p>
6033 This intrinsic adds <tt>delta</tt> to the value stored in memory at
6034 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6035</p>
6036<h5>Arguments:</h5>
6037<p>
6038
6039 The intrinsic takes two arguments, the first a pointer to an integer value
6040 and the second an integer value. The result is also an integer value. These
6041 integer types can have any bit width, but they must all have the same bit
6042 width. The targets may only lower integer representations they support.
6043</p>
6044<h5>Semantics:</h5>
6045<p>
6046 This intrinsic does a series of operations atomically. It first loads the
6047 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6048 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6049</p>
6050
6051<h5>Examples:</h5>
6052<pre>
6053%ptr = malloc i32
6054 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6055%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6056 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6057%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6058 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6059%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6060 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6061%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6062</pre>
6063</div>
6064
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6065<!-- _______________________________________________________________________ -->
6066<div class="doc_subsubsection">
6067 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6068
6069</div>
6070<div class="doc_text">
6071<h5>Syntax:</h5>
6072<p>
6073 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]6074 any integer bit width and for different address spaces. Not all targets
6075 support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6076<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6077declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6078declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6079declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6080declare 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]6081
6082</pre>
6083<h5>Overview:</h5>
6084<p>
6085 This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6086 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6087</p>
6088<h5>Arguments:</h5>
6089<p>
6090
6091 The intrinsic takes two arguments, the first a pointer to an integer value
6092 and the second an integer value. The result is also an integer value. These
6093 integer types can have any bit width, but they must all have the same bit
6094 width. The targets may only lower integer representations they support.
6095</p>
6096<h5>Semantics:</h5>
6097<p>
6098 This intrinsic does a series of operations atomically. It first loads the
6099 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6100 result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6101</p>
6102
6103<h5>Examples:</h5>
6104<pre>
6105%ptr = malloc i32
6106 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6107%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6108 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6109%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6110 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6111%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6112 <i>; yields {i32}:result3 = 2</i>
6113%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6114</pre>
6115</div>
6116
6117<!-- _______________________________________________________________________ -->
6118<div class="doc_subsubsection">
6119 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6120 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6121 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6122 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
6123
6124</div>
6125<div class="doc_text">
6126<h5>Syntax:</h5>
6127<p>
6128 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
6129 <tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6130 <tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
6131 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6132<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6133declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6134declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6135declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6136declare 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]6137
6138</pre>
6139
6140<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6141declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6142declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6143declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6144declare 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]6145
6146</pre>
6147
6148<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6149declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6150declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6151declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6152declare 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]6153
6154</pre>
6155
6156<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6157declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6158declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6159declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6160declare 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]6161
6162</pre>
6163<h5>Overview:</h5>
6164<p>
6165 These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6166 the value stored in memory at <tt>ptr</tt>. It yields the original value
6167 at <tt>ptr</tt>.
6168</p>
6169<h5>Arguments:</h5>
6170<p>
6171
6172 These intrinsics take two arguments, the first a pointer to an integer value
6173 and the second an integer value. The result is also an integer value. These
6174 integer types can have any bit width, but they must all have the same bit
6175 width. The targets may only lower integer representations they support.
6176</p>
6177<h5>Semantics:</h5>
6178<p>
6179 These intrinsics does a series of operations atomically. They first load the
6180 value stored at <tt>ptr</tt>. They then do the bitwise operation
6181 <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
6182 value stored at <tt>ptr</tt>.
6183</p>
6184
6185<h5>Examples:</h5>
6186<pre>
6187%ptr = malloc i32
6188 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6189%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6190 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6191%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6192 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6193%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6194 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6195%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6196 <i>; yields {i32}:result3 = FF</i>
6197%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6198</pre>
6199</div>
6200
6201
6202<!-- _______________________________________________________________________ -->
6203<div class="doc_subsubsection">
6204 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6205 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6206 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6207 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
6208
6209</div>
6210<div class="doc_text">
6211<h5>Syntax:</h5>
6212<p>
6213 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6214 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6215 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6216 address spaces. Not all targets
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6217 support all bit widths however.</p>
6218<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6219declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6220declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6221declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6222declare 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]6223
6224</pre>
6225
6226<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6227declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6228declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6229declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6230declare 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]6231
6232</pre>
6233
6234<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6235declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6236declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6237declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6238declare 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]6239
6240</pre>
6241
6242<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6243declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6244declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6245declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6246declare 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]6247
6248</pre>
6249<h5>Overview:</h5>
6250<p>
6251 These intrinsics takes the signed or unsigned minimum or maximum of
6252 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6253 original value at <tt>ptr</tt>.
6254</p>
6255<h5>Arguments:</h5>
6256<p>
6257
6258 These intrinsics take two arguments, the first a pointer to an integer value
6259 and the second an integer value. The result is also an integer value. These
6260 integer types can have any bit width, but they must all have the same bit
6261 width. The targets may only lower integer representations they support.
6262</p>
6263<h5>Semantics:</h5>
6264<p>
6265 These intrinsics does a series of operations atomically. They first load the
6266 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
6267 <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
6268 the original value stored at <tt>ptr</tt>.
6269</p>
6270
6271<h5>Examples:</h5>
6272<pre>
6273%ptr = malloc i32
6274 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6275%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6276 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6277%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6278 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6279%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6280 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6281%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6282 <i>; yields {i32}:result3 = 8</i>
6283%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6284</pre>
6285</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6286
6287<!-- ======================================================================= -->
6288<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6289 <a name="int_general">General Intrinsics</a>
6290</div>
6291
6292<div class="doc_text">
6293<p> This class of intrinsics is designed to be generic and has
6294no specific purpose. </p>
6295</div>
6296
6297<!-- _______________________________________________________________________ -->
6298<div class="doc_subsubsection">
6299 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6300</div>
6301
6302<div class="doc_text">
6303
6304<h5>Syntax:</h5>
6305<pre>
6306 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6307</pre>
6308
6309<h5>Overview:</h5>
6310
6311<p>
6312The '<tt>llvm.var.annotation</tt>' intrinsic
6313</p>
6314
6315<h5>Arguments:</h5>
6316
6317<p>
6318The first argument is a pointer to a value, the second is a pointer to a
6319global string, the third is a pointer to a global string which is the source
6320file name, and the last argument is the line number.
6321</p>
6322
6323<h5>Semantics:</h5>
6324
6325<p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6326This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6327This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6328annotations. These have no other defined use, they are ignored by code
6329generation and optimization.
6330</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6331</div>
6332
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6333<!-- _______________________________________________________________________ -->
6334<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]6335 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6336</div>
6337
6338<div class="doc_text">
6339
6340<h5>Syntax:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6341<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6342any integer bit width.
6343</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6344<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]6345 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6346 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6347 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6348 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6349 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]6350</pre>
6351
6352<h5>Overview:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6353
6354<p>
6355The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6356</p>
6357
6358<h5>Arguments:</h5>
6359
6360<p>
6361The first argument is an integer value (result of some expression),
6362the second is a pointer to a global string, the third is a pointer to a global
6363string which is the source file name, and the last argument is the line number.
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6364It returns the value of the first argument.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6365</p>
6366
6367<h5>Semantics:</h5>
6368
6369<p>
6370This intrinsic allows annotations to be put on arbitrary expressions
6371with arbitrary strings. This can be useful for special purpose optimizations
6372that want to look for these annotations. These have no other defined use, they
6373are ignored by code generation and optimization.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6374</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6375</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6376
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6377<!-- _______________________________________________________________________ -->
6378<div class="doc_subsubsection">
6379 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6380</div>
6381
6382<div class="doc_text">
6383
6384<h5>Syntax:</h5>
6385<pre>
6386 declare void @llvm.trap()
6387</pre>
6388
6389<h5>Overview:</h5>
6390
6391<p>
6392The '<tt>llvm.trap</tt>' intrinsic
6393</p>
6394
6395<h5>Arguments:</h5>
6396
6397<p>
6398None
6399</p>
6400
6401<h5>Semantics:</h5>
6402
6403<p>
6404This intrinsics is lowered to the target dependent trap instruction. If the
6405target does not have a trap instruction, this intrinsic will be lowered to the
6406call of the abort() function.
6407</p>
6408</div>
6409
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6410<!-- *********************************************************************** -->
6411<hr>
6412<address>
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Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6417
6418 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
6419 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
6420 Last modified: $Date$
6421</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]6422
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