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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>
27 <li><a href="#aliasstructure">Aliases</a>
28 <li><a href="#paramattrs">Parameter Attributes</a></li>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]29 <li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]30 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
31 <li><a href="#datalayout">Data Layout</a></li>
32 </ol>
33 </li>
34 <li><a href="#typesystem">Type System</a>
35 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]36 <li><a href="#t_classifications">Type Classifications</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]37 <li><a href="#t_primitive">Primitive Types</a>
38 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]39 <li><a href="#t_floating">Floating Point Types</a></li>
40 <li><a href="#t_void">Void Type</a></li>
41 <li><a href="#t_label">Label Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]42 </ol>
43 </li>
44 <li><a href="#t_derived">Derived Types</a>
45 <ol>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]46 <li><a href="#t_integer">Integer Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]47 <li><a href="#t_array">Array Type</a></li>
48 <li><a href="#t_function">Function Type</a></li>
49 <li><a href="#t_pointer">Pointer Type</a></li>
50 <li><a href="#t_struct">Structure Type</a></li>
51 <li><a href="#t_pstruct">Packed Structure Type</a></li>
52 <li><a href="#t_vector">Vector Type</a></li>
53 <li><a href="#t_opaque">Opaque Type</a></li>
54 </ol>
55 </li>
56 </ol>
57 </li>
58 <li><a href="#constants">Constants</a>
59 <ol>
60 <li><a href="#simpleconstants">Simple Constants</a>
61 <li><a href="#aggregateconstants">Aggregate Constants</a>
62 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
63 <li><a href="#undefvalues">Undefined Values</a>
64 <li><a href="#constantexprs">Constant Expressions</a>
65 </ol>
66 </li>
67 <li><a href="#othervalues">Other Values</a>
68 <ol>
69 <li><a href="#inlineasm">Inline Assembler Expressions</a>
70 </ol>
71 </li>
72 <li><a href="#instref">Instruction Reference</a>
73 <ol>
74 <li><a href="#terminators">Terminator Instructions</a>
75 <ol>
76 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
77 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
78 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
79 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
80 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
81 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
82 </ol>
83 </li>
84 <li><a href="#binaryops">Binary Operations</a>
85 <ol>
86 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
87 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
88 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
89 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
90 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
91 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
92 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
93 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
94 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
95 </ol>
96 </li>
97 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
98 <ol>
99 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
100 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
101 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
102 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
103 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
104 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
105 </ol>
106 </li>
107 <li><a href="#vectorops">Vector Operations</a>
108 <ol>
109 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
110 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
111 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
112 </ol>
113 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]114 <li><a href="#aggregateops">Aggregate Operations</a>
115 <ol>
116 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
117 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
118 </ol>
119 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]120 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
121 <ol>
122 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
123 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
124 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
125 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
126 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
127 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
128 </ol>
129 </li>
130 <li><a href="#convertops">Conversion Operations</a>
131 <ol>
132 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
133 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
134 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
135 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
136 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
137 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
138 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
139 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
140 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
141 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
142 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
143 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
144 </ol>
145 <li><a href="#otherops">Other Operations</a>
146 <ol>
147 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
148 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]149 <li><a href="#i_vicmp">'<tt>vicmp</tt>' Instruction</a></li>
150 <li><a href="#i_vfcmp">'<tt>vfcmp</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]151 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
152 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
153 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
154 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]155 <li><a href="#i_getresult">'<tt>getresult</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]156 </ol>
157 </li>
158 </ol>
159 </li>
160 <li><a href="#intrinsics">Intrinsic Functions</a>
161 <ol>
162 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
163 <ol>
164 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
165 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
166 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
167 </ol>
168 </li>
169 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
170 <ol>
171 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
172 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
173 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
174 </ol>
175 </li>
176 <li><a href="#int_codegen">Code Generator Intrinsics</a>
177 <ol>
178 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
179 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
180 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
181 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
182 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
183 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
184 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
185 </ol>
186 </li>
187 <li><a href="#int_libc">Standard C Library Intrinsics</a>
188 <ol>
189 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
190 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
191 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
192 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
193 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]194 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
195 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
196 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]197 </ol>
198 </li>
199 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
200 <ol>
201 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
202 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
203 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
204 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
205 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
206 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
207 </ol>
208 </li>
209 <li><a href="#int_debugger">Debugger intrinsics</a></li>
210 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]211 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]212 <ol>
213 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]214 </ol>
215 </li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]216 <li><a href="#int_atomics">Atomic intrinsics</a>
217 <ol>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]218 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]219 <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]220 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]221 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
222 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
223 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
224 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
225 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
226 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
227 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
228 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
229 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
230 <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]231 </ol>
232 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]233 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]234 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]235 <li><a href="#int_var_annotation">
Tanya Lattner51369f32007-09-22 00:01:26 +0000[diff] [blame]236 <tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]237 <li><a href="#int_annotation">
Tanya Lattner51369f32007-09-22 00:01:26 +0000[diff] [blame]238 <tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]239 <li><a href="#int_trap">
240 <tt>llvm.trap</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]241 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]242 </li>
243 </ol>
244 </li>
245</ol>
246
247<div class="doc_author">
248 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
249 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
250</div>
251
252<!-- *********************************************************************** -->
253<div class="doc_section"> <a name="abstract">Abstract </a></div>
254<!-- *********************************************************************** -->
255
256<div class="doc_text">
257<p>This document is a reference manual for the LLVM assembly language.
258LLVM is an SSA based representation that provides type safety,
259low-level operations, flexibility, and the capability of representing
260'all' high-level languages cleanly. It is the common code
261representation used throughout all phases of the LLVM compilation
262strategy.</p>
263</div>
264
265<!-- *********************************************************************** -->
266<div class="doc_section"> <a name="introduction">Introduction</a> </div>
267<!-- *********************************************************************** -->
268
269<div class="doc_text">
270
271<p>The LLVM code representation is designed to be used in three
272different forms: as an in-memory compiler IR, as an on-disk bitcode
273representation (suitable for fast loading by a Just-In-Time compiler),
274and as a human readable assembly language representation. This allows
275LLVM to provide a powerful intermediate representation for efficient
276compiler transformations and analysis, while providing a natural means
277to debug and visualize the transformations. The three different forms
278of LLVM are all equivalent. This document describes the human readable
279representation and notation.</p>
280
281<p>The LLVM representation aims to be light-weight and low-level
282while being expressive, typed, and extensible at the same time. It
283aims to be a "universal IR" of sorts, by being at a low enough level
284that high-level ideas may be cleanly mapped to it (similar to how
285microprocessors are "universal IR's", allowing many source languages to
286be mapped to them). By providing type information, LLVM can be used as
287the target of optimizations: for example, through pointer analysis, it
288can be proven that a C automatic variable is never accessed outside of
289the current function... allowing it to be promoted to a simple SSA
290value instead of a memory location.</p>
291
292</div>
293
294<!-- _______________________________________________________________________ -->
295<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
296
297<div class="doc_text">
298
299<p>It is important to note that this document describes 'well formed'
300LLVM assembly language. There is a difference between what the parser
301accepts and what is considered 'well formed'. For example, the
302following instruction is syntactically okay, but not well formed:</p>
303
304<div class="doc_code">
305<pre>
306%x = <a href="#i_add">add</a> i32 1, %x
307</pre>
308</div>
309
310<p>...because the definition of <tt>%x</tt> does not dominate all of
311its uses. The LLVM infrastructure provides a verification pass that may
312be used to verify that an LLVM module is well formed. This pass is
313automatically run by the parser after parsing input assembly and by
314the optimizer before it outputs bitcode. The violations pointed out
315by the verifier pass indicate bugs in transformation passes or input to
316the parser.</p>
317</div>
318
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]319<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]320
321<!-- *********************************************************************** -->
322<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
323<!-- *********************************************************************** -->
324
325<div class="doc_text">
326
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]327 <p>LLVM identifiers come in two basic types: global and local. Global
328 identifiers (functions, global variables) begin with the @ character. Local
329 identifiers (register names, types) begin with the % character. Additionally,
330 there are three different formats for identifiers, for different purposes:
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]331
332<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]333 <li>Named values are represented as a string of characters with their prefix.
334 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
335 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]336 Identifiers which require other characters in their names can be surrounded
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]337 with quotes. In this way, anything except a <tt>&quot;</tt> character can
338 be used in a named value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]339
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]340 <li>Unnamed values are represented as an unsigned numeric value with their
341 prefix. For example, %12, @2, %44.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]342
343 <li>Constants, which are described in a <a href="#constants">section about
344 constants</a>, below.</li>
345</ol>
346
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]347<p>LLVM requires that values start with a prefix for two reasons: Compilers
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]348don't need to worry about name clashes with reserved words, and the set of
349reserved words may be expanded in the future without penalty. Additionally,
350unnamed identifiers allow a compiler to quickly come up with a temporary
351variable without having to avoid symbol table conflicts.</p>
352
353<p>Reserved words in LLVM are very similar to reserved words in other
354languages. There are keywords for different opcodes
355('<tt><a href="#i_add">add</a></tt>',
356 '<tt><a href="#i_bitcast">bitcast</a></tt>',
357 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
358href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
359and others. These reserved words cannot conflict with variable names, because
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]360none of them start with a prefix character ('%' or '@').</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]361
362<p>Here is an example of LLVM code to multiply the integer variable
363'<tt>%X</tt>' by 8:</p>
364
365<p>The easy way:</p>
366
367<div class="doc_code">
368<pre>
369%result = <a href="#i_mul">mul</a> i32 %X, 8
370</pre>
371</div>
372
373<p>After strength reduction:</p>
374
375<div class="doc_code">
376<pre>
377%result = <a href="#i_shl">shl</a> i32 %X, i8 3
378</pre>
379</div>
380
381<p>And the hard way:</p>
382
383<div class="doc_code">
384<pre>
385<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
386<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
387%result = <a href="#i_add">add</a> i32 %1, %1
388</pre>
389</div>
390
391<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
392important lexical features of LLVM:</p>
393
394<ol>
395
396 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
397 line.</li>
398
399 <li>Unnamed temporaries are created when the result of a computation is not
400 assigned to a named value.</li>
401
402 <li>Unnamed temporaries are numbered sequentially</li>
403
404</ol>
405
406<p>...and it also shows a convention that we follow in this document. When
407demonstrating instructions, we will follow an instruction with a comment that
408defines the type and name of value produced. Comments are shown in italic
409text.</p>
410
411</div>
412
413<!-- *********************************************************************** -->
414<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
415<!-- *********************************************************************** -->
416
417<!-- ======================================================================= -->
418<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
419</div>
420
421<div class="doc_text">
422
423<p>LLVM programs are composed of "Module"s, each of which is a
424translation unit of the input programs. Each module consists of
425functions, global variables, and symbol table entries. Modules may be
426combined together with the LLVM linker, which merges function (and
427global variable) definitions, resolves forward declarations, and merges
428symbol table entries. Here is an example of the "hello world" module:</p>
429
430<div class="doc_code">
431<pre><i>; Declare the string constant as a global constant...</i>
432<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
433 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
434
435<i>; External declaration of the puts function</i>
436<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
437
438<i>; Definition of main function</i>
439define i32 @main() { <i>; i32()* </i>
440 <i>; Convert [13x i8 ]* to i8 *...</i>
441 %cast210 = <a
442 href="#i_getelementptr">getelementptr</a> [13 x i8 ]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
443
444 <i>; Call puts function to write out the string to stdout...</i>
445 <a
446 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
447 <a
448 href="#i_ret">ret</a> i32 0<br>}<br>
449</pre>
450</div>
451
452<p>This example is made up of a <a href="#globalvars">global variable</a>
453named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
454function, and a <a href="#functionstructure">function definition</a>
455for "<tt>main</tt>".</p>
456
457<p>In general, a module is made up of a list of global values,
458where both functions and global variables are global values. Global values are
459represented by a pointer to a memory location (in this case, a pointer to an
460array of char, and a pointer to a function), and have one of the following <a
461href="#linkage">linkage types</a>.</p>
462
463</div>
464
465<!-- ======================================================================= -->
466<div class="doc_subsection">
467 <a name="linkage">Linkage Types</a>
468</div>
469
470<div class="doc_text">
471
472<p>
473All Global Variables and Functions have one of the following types of linkage:
474</p>
475
476<dl>
477
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]478 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]479
480 <dd>Global values with internal linkage are only directly accessible by
481 objects in the current module. In particular, linking code into a module with
482 an internal global value may cause the internal to be renamed as necessary to
483 avoid collisions. Because the symbol is internal to the module, all
484 references can be updated. This corresponds to the notion of the
485 '<tt>static</tt>' keyword in C.
486 </dd>
487
488 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
489
490 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
491 the same name when linkage occurs. This is typically used to implement
492 inline functions, templates, or other code which must be generated in each
493 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
494 allowed to be discarded.
495 </dd>
496
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]497 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
498
499 <dd>"<tt>common</tt>" linkage is exactly the same as <tt>linkonce</tt>
500 linkage, except that unreferenced <tt>common</tt> globals may not be
501 discarded. This is used for globals that may be emitted in multiple
502 translation units, but that are not guaranteed to be emitted into every
503 translation unit that uses them. One example of this is tentative
504 definitions in C, such as "<tt>int X;</tt>" at global scope.
505 </dd>
506
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]507 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
508
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]509 <dd>"<tt>weak</tt>" linkage is the same as <tt>common</tt> linkage, except
510 that some targets may choose to emit different assembly sequences for them
511 for target-dependent reasons. This is used for globals that are declared
512 "weak" in C source code.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]513 </dd>
514
515 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
516
517 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
518 pointer to array type. When two global variables with appending linkage are
519 linked together, the two global arrays are appended together. This is the
520 LLVM, typesafe, equivalent of having the system linker append together
521 "sections" with identical names when .o files are linked.
522 </dd>
523
524 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
525 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
526 until linked, if not linked, the symbol becomes null instead of being an
527 undefined reference.
528 </dd>
529
530 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
531
532 <dd>If none of the above identifiers are used, the global is externally
533 visible, meaning that it participates in linkage and can be used to resolve
534 external symbol references.
535 </dd>
536</dl>
537
538 <p>
539 The next two types of linkage are targeted for Microsoft Windows platform
540 only. They are designed to support importing (exporting) symbols from (to)
541 DLLs.
542 </p>
543
544 <dl>
545 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
546
547 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
548 or variable via a global pointer to a pointer that is set up by the DLL
549 exporting the symbol. On Microsoft Windows targets, the pointer name is
550 formed by combining <code>_imp__</code> and the function or variable name.
551 </dd>
552
553 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
554
555 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
556 pointer to a pointer in a DLL, so that it can be referenced with the
557 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
558 name is formed by combining <code>_imp__</code> and the function or variable
559 name.
560 </dd>
561
562</dl>
563
564<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
565variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
566variable and was linked with this one, one of the two would be renamed,
567preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
568external (i.e., lacking any linkage declarations), they are accessible
569outside of the current module.</p>
570<p>It is illegal for a function <i>declaration</i>
571to have any linkage type other than "externally visible", <tt>dllimport</tt>,
572or <tt>extern_weak</tt>.</p>
573<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
574linkages.
575</div>
576
577<!-- ======================================================================= -->
578<div class="doc_subsection">
579 <a name="callingconv">Calling Conventions</a>
580</div>
581
582<div class="doc_text">
583
584<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
585and <a href="#i_invoke">invokes</a> can all have an optional calling convention
586specified for the call. The calling convention of any pair of dynamic
587caller/callee must match, or the behavior of the program is undefined. The
588following calling conventions are supported by LLVM, and more may be added in
589the future:</p>
590
591<dl>
592 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
593
594 <dd>This calling convention (the default if no other calling convention is
595 specified) matches the target C calling conventions. This calling convention
596 supports varargs function calls and tolerates some mismatch in the declared
597 prototype and implemented declaration of the function (as does normal C).
598 </dd>
599
600 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
601
602 <dd>This calling convention attempts to make calls as fast as possible
603 (e.g. by passing things in registers). This calling convention allows the
604 target to use whatever tricks it wants to produce fast code for the target,
605 without having to conform to an externally specified ABI. Implementations of
Arnold Schwaighofer07444922008-05-14 09:17:12 +0000[diff] [blame]606 this convention should allow arbitrary
607 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> to be
608 supported. This calling convention does not support varargs and requires the
609 prototype of all callees to exactly match the prototype of the function
610 definition.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]611 </dd>
612
613 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
614
615 <dd>This calling convention attempts to make code in the caller as efficient
616 as possible under the assumption that the call is not commonly executed. As
617 such, these calls often preserve all registers so that the call does not break
618 any live ranges in the caller side. This calling convention does not support
619 varargs and requires the prototype of all callees to exactly match the
620 prototype of the function definition.
621 </dd>
622
623 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
624
625 <dd>Any calling convention may be specified by number, allowing
626 target-specific calling conventions to be used. Target specific calling
627 conventions start at 64.
628 </dd>
629</dl>
630
631<p>More calling conventions can be added/defined on an as-needed basis, to
632support pascal conventions or any other well-known target-independent
633convention.</p>
634
635</div>
636
637<!-- ======================================================================= -->
638<div class="doc_subsection">
639 <a name="visibility">Visibility Styles</a>
640</div>
641
642<div class="doc_text">
643
644<p>
645All Global Variables and Functions have one of the following visibility styles:
646</p>
647
648<dl>
649 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
650
651 <dd>On ELF, default visibility means that the declaration is visible to other
652 modules and, in shared libraries, means that the declared entity may be
653 overridden. On Darwin, default visibility means that the declaration is
654 visible to other modules. Default visibility corresponds to "external
655 linkage" in the language.
656 </dd>
657
658 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
659
660 <dd>Two declarations of an object with hidden visibility refer to the same
661 object if they are in the same shared object. Usually, hidden visibility
662 indicates that the symbol will not be placed into the dynamic symbol table,
663 so no other module (executable or shared library) can reference it
664 directly.
665 </dd>
666
667 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
668
669 <dd>On ELF, protected visibility indicates that the symbol will be placed in
670 the dynamic symbol table, but that references within the defining module will
671 bind to the local symbol. That is, the symbol cannot be overridden by another
672 module.
673 </dd>
674</dl>
675
676</div>
677
678<!-- ======================================================================= -->
679<div class="doc_subsection">
680 <a name="globalvars">Global Variables</a>
681</div>
682
683<div class="doc_text">
684
685<p>Global variables define regions of memory allocated at compilation time
686instead of run-time. Global variables may optionally be initialized, may have
687an explicit section to be placed in, and may have an optional explicit alignment
688specified. A variable may be defined as "thread_local", which means that it
689will not be shared by threads (each thread will have a separated copy of the
690variable). A variable may be defined as a global "constant," which indicates
691that the contents of the variable will <b>never</b> be modified (enabling better
692optimization, allowing the global data to be placed in the read-only section of
693an executable, etc). Note that variables that need runtime initialization
694cannot be marked "constant" as there is a store to the variable.</p>
695
696<p>
697LLVM explicitly allows <em>declarations</em> of global variables to be marked
698constant, even if the final definition of the global is not. This capability
699can be used to enable slightly better optimization of the program, but requires
700the language definition to guarantee that optimizations based on the
701'constantness' are valid for the translation units that do not include the
702definition.
703</p>
704
705<p>As SSA values, global variables define pointer values that are in
706scope (i.e. they dominate) all basic blocks in the program. Global
707variables always define a pointer to their "content" type because they
708describe a region of memory, and all memory objects in LLVM are
709accessed through pointers.</p>
710
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]711<p>A global variable may be declared to reside in a target-specifc numbered
712address space. For targets that support them, address spaces may affect how
713optimizations are performed and/or what target instructions are used to access
Christopher Lamb20a39e92007-12-12 08:44:39 +0000[diff] [blame]714the variable. The default address space is zero. The address space qualifier
715must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]716
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]717<p>LLVM allows an explicit section to be specified for globals. If the target
718supports it, it will emit globals to the section specified.</p>
719
720<p>An explicit alignment may be specified for a global. If not present, or if
721the alignment is set to zero, the alignment of the global is set by the target
722to whatever it feels convenient. If an explicit alignment is specified, the
723global is forced to have at least that much alignment. All alignments must be
724a power of 2.</p>
725
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]726<p>For example, the following defines a global in a numbered address space with
727an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]728
729<div class="doc_code">
730<pre>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]731@G = constant float 1.0 addrspace(5), section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]732</pre>
733</div>
734
735</div>
736
737
738<!-- ======================================================================= -->
739<div class="doc_subsection">
740 <a name="functionstructure">Functions</a>
741</div>
742
743<div class="doc_text">
744
745<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
746an optional <a href="#linkage">linkage type</a>, an optional
747<a href="#visibility">visibility style</a>, an optional
748<a href="#callingconv">calling convention</a>, a return type, an optional
749<a href="#paramattrs">parameter attribute</a> for the return type, a function
750name, a (possibly empty) argument list (each with optional
751<a href="#paramattrs">parameter attributes</a>), an optional section, an
Gordon Henriksend606f5b2007-12-10 03:30:21 +0000[diff] [blame]752optional alignment, an optional <a href="#gc">garbage collector name</a>, an
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]753opening curly brace, a list of basic blocks, and a closing curly brace.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]754
755LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
756optional <a href="#linkage">linkage type</a>, an optional
757<a href="#visibility">visibility style</a>, an optional
758<a href="#callingconv">calling convention</a>, a return type, an optional
759<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]760name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksend606f5b2007-12-10 03:30:21 +0000[diff] [blame]761<a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]762
763<p>A function definition contains a list of basic blocks, forming the CFG for
764the function. Each basic block may optionally start with a label (giving the
765basic block a symbol table entry), contains a list of instructions, and ends
766with a <a href="#terminators">terminator</a> instruction (such as a branch or
767function return).</p>
768
769<p>The first basic block in a function is special in two ways: it is immediately
770executed on entrance to the function, and it is not allowed to have predecessor
771basic blocks (i.e. there can not be any branches to the entry block of a
772function). Because the block can have no predecessors, it also cannot have any
773<a href="#i_phi">PHI nodes</a>.</p>
774
775<p>LLVM allows an explicit section to be specified for functions. If the target
776supports it, it will emit functions to the section specified.</p>
777
778<p>An explicit alignment may be specified for a function. If not present, or if
779the alignment is set to zero, the alignment of the function is set by the target
780to whatever it feels convenient. If an explicit alignment is specified, the
781function is forced to have at least that much alignment. All alignments must be
782a power of 2.</p>
783
784</div>
785
786
787<!-- ======================================================================= -->
788<div class="doc_subsection">
789 <a name="aliasstructure">Aliases</a>
790</div>
791<div class="doc_text">
792 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikov96822812008-03-22 08:36:14 +0000[diff] [blame]793 function, global variable, another alias or bitcast of global value). Aliases
794 may have an optional <a href="#linkage">linkage type</a>, and an
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]795 optional <a href="#visibility">visibility style</a>.</p>
796
797 <h5>Syntax:</h5>
798
799<div class="doc_code">
800<pre>
801@&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
802</pre>
803</div>
804
805</div>
806
807
808
809<!-- ======================================================================= -->
810<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
811<div class="doc_text">
812 <p>The return type and each parameter of a function type may have a set of
813 <i>parameter attributes</i> associated with them. Parameter attributes are
814 used to communicate additional information about the result or parameters of
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]815 a function. Parameter attributes are considered to be part of the function,
816 not of the function type, so functions with different parameter attributes
817 can have the same function type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]818
819 <p>Parameter attributes are simple keywords that follow the type specified. If
820 multiple parameter attributes are needed, they are space separated. For
821 example:</p>
822
823<div class="doc_code">
824<pre>
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]825declare i32 @printf(i8* noalias , ...) nounwind
826declare i32 @atoi(i8*) nounwind readonly
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]827</pre>
828</div>
829
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]830 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
831 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]832
833 <p>Currently, only the following parameter attributes are defined:</p>
834 <dl>
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]835 <dt><tt>zeroext</tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]836 <dd>This indicates that the parameter should be zero extended just before
837 a call to this function.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]838
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]839 <dt><tt>signext</tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]840 <dd>This indicates that the parameter should be sign extended just before
841 a call to this function.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]842
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]843 <dt><tt>inreg</tt></dt>
844 <dd>This indicates that the parameter should be placed in register (if
845 possible) during assembling function call. Support for this attribute is
846 target-specific</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]847
848 <dt><tt>byval</tt></dt>
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]849 <dd>This indicates that the pointer parameter should really be passed by
850 value to the function. The attribute implies that a hidden copy of the
851 pointee is made between the caller and the callee, so the callee is unable
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]852 to modify the value in the callee. This attribute is only valid on LLVM
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]853 pointer arguments. It is generally used to pass structs and arrays by
854 value, but is also valid on scalars (even though this is silly).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]855
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]856 <dt><tt>sret</tt></dt>
Duncan Sands616cc032008-02-18 04:19:38 +0000[diff] [blame]857 <dd>This indicates that the pointer parameter specifies the address of a
858 structure that is the return value of the function in the source program.
Duncan Sandsef0e9e42008-03-17 12:17:41 +0000[diff] [blame]859 Loads and stores to the structure are assumed not to trap.
Duncan Sands616cc032008-02-18 04:19:38 +0000[diff] [blame]860 May only be applied to the first parameter.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]861
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]862 <dt><tt>noalias</tt></dt>
Owen Andersonc4fc4cd2008-02-18 04:09:01 +0000[diff] [blame]863 <dd>This indicates that the parameter does not alias any global or any other
864 parameter. The caller is responsible for ensuring that this is the case,
865 usually by placing the value in a stack allocation.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]866
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]867 <dt><tt>noreturn</tt></dt>
868 <dd>This function attribute indicates that the function never returns. This
869 indicates to LLVM that every call to this function should be treated as if
870 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]871
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]872 <dt><tt>nounwind</tt></dt>
Duncan Sandsef0e9e42008-03-17 12:17:41 +0000[diff] [blame]873 <dd>This function attribute indicates that no exceptions unwind out of the
874 function. Usually this is because the function makes no use of exceptions,
875 but it may also be that the function catches any exceptions thrown when
876 executing it.</dd>
877
Duncan Sands4ee46812007-07-27 19:57:41 +0000[diff] [blame]878 <dt><tt>nest</tt></dt>
Duncan Sandsf1a7d4c2008-07-08 09:27:25 +0000[diff] [blame]879 <dd>This indicates that the pointer parameter can be excised using the
Duncan Sands4ee46812007-07-27 19:57:41 +0000[diff] [blame]880 <a href="#int_trampoline">trampoline intrinsics</a>.</dd>
Duncan Sands13e13f82007-11-22 20:23:04 +0000[diff] [blame]881 <dt><tt>readonly</tt></dt>
Duncan Sandsd69c0e62007-11-14 21:14:02 +0000[diff] [blame]882 <dd>This function attribute indicates that the function has no side-effects
Duncan Sands13e13f82007-11-22 20:23:04 +0000[diff] [blame]883 except for producing a return value or throwing an exception. The value
884 returned must only depend on the function arguments and/or global variables.
885 It may use values obtained by dereferencing pointers.</dd>
886 <dt><tt>readnone</tt></dt>
887 <dd>A <tt>readnone</tt> function has the same restrictions as a <tt>readonly</tt>
Duncan Sandsd69c0e62007-11-14 21:14:02 +0000[diff] [blame]888 function, but in addition it is not allowed to dereference any pointer arguments
889 or global variables.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]890 </dl>
891
892</div>
893
894<!-- ======================================================================= -->
895<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]896 <a name="gc">Garbage Collector Names</a>
897</div>
898
899<div class="doc_text">
900<p>Each function may specify a garbage collector name, which is simply a
901string.</p>
902
903<div class="doc_code"><pre
904>define void @f() gc "name" { ...</pre></div>
905
906<p>The compiler declares the supported values of <i>name</i>. Specifying a
907collector which will cause the compiler to alter its output in order to support
908the named garbage collection algorithm.</p>
909</div>
910
911<!-- ======================================================================= -->
912<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]913 <a name="moduleasm">Module-Level Inline Assembly</a>
914</div>
915
916<div class="doc_text">
917<p>
918Modules may contain "module-level inline asm" blocks, which corresponds to the
919GCC "file scope inline asm" blocks. These blocks are internally concatenated by
920LLVM and treated as a single unit, but may be separated in the .ll file if
921desired. The syntax is very simple:
922</p>
923
924<div class="doc_code">
925<pre>
926module asm "inline asm code goes here"
927module asm "more can go here"
928</pre>
929</div>
930
931<p>The strings can contain any character by escaping non-printable characters.
932 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
933 for the number.
934</p>
935
936<p>
937 The inline asm code is simply printed to the machine code .s file when
938 assembly code is generated.
939</p>
940</div>
941
942<!-- ======================================================================= -->
943<div class="doc_subsection">
944 <a name="datalayout">Data Layout</a>
945</div>
946
947<div class="doc_text">
948<p>A module may specify a target specific data layout string that specifies how
949data is to be laid out in memory. The syntax for the data layout is simply:</p>
950<pre> target datalayout = "<i>layout specification</i>"</pre>
951<p>The <i>layout specification</i> consists of a list of specifications
952separated by the minus sign character ('-'). Each specification starts with a
953letter and may include other information after the letter to define some
954aspect of the data layout. The specifications accepted are as follows: </p>
955<dl>
956 <dt><tt>E</tt></dt>
957 <dd>Specifies that the target lays out data in big-endian form. That is, the
958 bits with the most significance have the lowest address location.</dd>
959 <dt><tt>e</tt></dt>
960 <dd>Specifies that hte target lays out data in little-endian form. That is,
961 the bits with the least significance have the lowest address location.</dd>
962 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
963 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
964 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
965 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
966 too.</dd>
967 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
968 <dd>This specifies the alignment for an integer type of a given bit
969 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
970 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
971 <dd>This specifies the alignment for a vector type of a given bit
972 <i>size</i>.</dd>
973 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
974 <dd>This specifies the alignment for a floating point type of a given bit
975 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
976 (double).</dd>
977 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
978 <dd>This specifies the alignment for an aggregate type of a given bit
979 <i>size</i>.</dd>
980</dl>
981<p>When constructing the data layout for a given target, LLVM starts with a
982default set of specifications which are then (possibly) overriden by the
983specifications in the <tt>datalayout</tt> keyword. The default specifications
984are given in this list:</p>
985<ul>
986 <li><tt>E</tt> - big endian</li>
987 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
988 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
989 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
990 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
991 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
992 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
993 alignment of 64-bits</li>
994 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
995 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
996 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
997 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
998 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
999</ul>
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]1000<p>When LLVM is determining the alignment for a given type, it uses the
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1001following rules:
1002<ol>
1003 <li>If the type sought is an exact match for one of the specifications, that
1004 specification is used.</li>
1005 <li>If no match is found, and the type sought is an integer type, then the
1006 smallest integer type that is larger than the bitwidth of the sought type is
1007 used. If none of the specifications are larger than the bitwidth then the the
1008 largest integer type is used. For example, given the default specifications
1009 above, the i7 type will use the alignment of i8 (next largest) while both
1010 i65 and i256 will use the alignment of i64 (largest specified).</li>
1011 <li>If no match is found, and the type sought is a vector type, then the
1012 largest vector type that is smaller than the sought vector type will be used
1013 as a fall back. This happens because <128 x double> can be implemented in
1014 terms of 64 <2 x double>, for example.</li>
1015</ol>
1016</div>
1017
1018<!-- *********************************************************************** -->
1019<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1020<!-- *********************************************************************** -->
1021
1022<div class="doc_text">
1023
1024<p>The LLVM type system is one of the most important features of the
1025intermediate representation. Being typed enables a number of
1026optimizations to be performed on the IR directly, without having to do
1027extra analyses on the side before the transformation. A strong type
1028system makes it easier to read the generated code and enables novel
1029analyses and transformations that are not feasible to perform on normal
1030three address code representations.</p>
1031
1032</div>
1033
1034<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1035<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1036Classifications</a> </div>
1037<div class="doc_text">
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1038<p>The types fall into a few useful
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1039classifications:</p>
1040
1041<table border="1" cellspacing="0" cellpadding="4">
1042 <tbody>
1043 <tr><th>Classification</th><th>Types</th></tr>
1044 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1045 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1046 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1047 </tr>
1048 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1049 <td><a href="#t_floating">floating point</a></td>
1050 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1051 </tr>
1052 <tr>
1053 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1054 <td><a href="#t_integer">integer</a>,
1055 <a href="#t_floating">floating point</a>,
1056 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1057 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1058 <a href="#t_struct">structure</a>,
1059 <a href="#t_array">array</a>,
Dan Gohmand13951e2008-05-23 22:50:26 +0000[diff] [blame]1060 <a href="#t_label">label</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1061 </td>
1062 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1063 <tr>
1064 <td><a href="#t_primitive">primitive</a></td>
1065 <td><a href="#t_label">label</a>,
1066 <a href="#t_void">void</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1067 <a href="#t_floating">floating point</a>.</td>
1068 </tr>
1069 <tr>
1070 <td><a href="#t_derived">derived</a></td>
1071 <td><a href="#t_integer">integer</a>,
1072 <a href="#t_array">array</a>,
1073 <a href="#t_function">function</a>,
1074 <a href="#t_pointer">pointer</a>,
1075 <a href="#t_struct">structure</a>,
1076 <a href="#t_pstruct">packed structure</a>,
1077 <a href="#t_vector">vector</a>,
1078 <a href="#t_opaque">opaque</a>.
1079 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1080 </tbody>
1081</table>
1082
1083<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1084most important. Values of these types are the only ones which can be
1085produced by instructions, passed as arguments, or used as operands to
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]1086instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1087</div>
1088
1089<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1090<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1091
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1092<div class="doc_text">
1093<p>The primitive types are the fundamental building blocks of the LLVM
1094system.</p>
1095
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1096</div>
1097
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1098<!-- _______________________________________________________________________ -->
1099<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1100
1101<div class="doc_text">
1102 <table>
1103 <tbody>
1104 <tr><th>Type</th><th>Description</th></tr>
1105 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1106 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1107 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1108 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1109 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1110 </tbody>
1111 </table>
1112</div>
1113
1114<!-- _______________________________________________________________________ -->
1115<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1116
1117<div class="doc_text">
1118<h5>Overview:</h5>
1119<p>The void type does not represent any value and has no size.</p>
1120
1121<h5>Syntax:</h5>
1122
1123<pre>
1124 void
1125</pre>
1126</div>
1127
1128<!-- _______________________________________________________________________ -->
1129<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1130
1131<div class="doc_text">
1132<h5>Overview:</h5>
1133<p>The label type represents code labels.</p>
1134
1135<h5>Syntax:</h5>
1136
1137<pre>
1138 label
1139</pre>
1140</div>
1141
1142
1143<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1144<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1145
1146<div class="doc_text">
1147
1148<p>The real power in LLVM comes from the derived types in the system.
1149This is what allows a programmer to represent arrays, functions,
1150pointers, and other useful types. Note that these derived types may be
1151recursive: For example, it is possible to have a two dimensional array.</p>
1152
1153</div>
1154
1155<!-- _______________________________________________________________________ -->
1156<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1157
1158<div class="doc_text">
1159
1160<h5>Overview:</h5>
1161<p>The integer type is a very simple derived type that simply specifies an
1162arbitrary bit width for the integer type desired. Any bit width from 1 bit to
11632^23-1 (about 8 million) can be specified.</p>
1164
1165<h5>Syntax:</h5>
1166
1167<pre>
1168 iN
1169</pre>
1170
1171<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1172value.</p>
1173
1174<h5>Examples:</h5>
1175<table class="layout">
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1176 <tbody>
1177 <tr>
1178 <td><tt>i1</tt></td>
1179 <td>a single-bit integer.</td>
1180 </tr><tr>
1181 <td><tt>i32</tt></td>
1182 <td>a 32-bit integer.</td>
1183 </tr><tr>
1184 <td><tt>i1942652</tt></td>
1185 <td>a really big integer of over 1 million bits.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1186 </tr>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1187 </tbody>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1188</table>
1189</div>
1190
1191<!-- _______________________________________________________________________ -->
1192<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1193
1194<div class="doc_text">
1195
1196<h5>Overview:</h5>
1197
1198<p>The array type is a very simple derived type that arranges elements
1199sequentially in memory. The array type requires a size (number of
1200elements) and an underlying data type.</p>
1201
1202<h5>Syntax:</h5>
1203
1204<pre>
1205 [&lt;# elements&gt; x &lt;elementtype&gt;]
1206</pre>
1207
1208<p>The number of elements is a constant integer value; elementtype may
1209be any type with a size.</p>
1210
1211<h5>Examples:</h5>
1212<table class="layout">
1213 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1214 <td class="left"><tt>[40 x i32]</tt></td>
1215 <td class="left">Array of 40 32-bit integer values.</td>
1216 </tr>
1217 <tr class="layout">
1218 <td class="left"><tt>[41 x i32]</tt></td>
1219 <td class="left">Array of 41 32-bit integer values.</td>
1220 </tr>
1221 <tr class="layout">
1222 <td class="left"><tt>[4 x i8]</tt></td>
1223 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1224 </tr>
1225</table>
1226<p>Here are some examples of multidimensional arrays:</p>
1227<table class="layout">
1228 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1229 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1230 <td class="left">3x4 array of 32-bit integer values.</td>
1231 </tr>
1232 <tr class="layout">
1233 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1234 <td class="left">12x10 array of single precision floating point values.</td>
1235 </tr>
1236 <tr class="layout">
1237 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1238 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1239 </tr>
1240</table>
1241
1242<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1243length array. Normally, accesses past the end of an array are undefined in
1244LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1245As a special case, however, zero length arrays are recognized to be variable
1246length. This allows implementation of 'pascal style arrays' with the LLVM
1247type "{ i32, [0 x float]}", for example.</p>
1248
1249</div>
1250
1251<!-- _______________________________________________________________________ -->
1252<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
1253<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1254
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1255<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1256
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1257<p>The function type can be thought of as a function signature. It
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1258consists of a return type and a list of formal parameter types. The
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1259return 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]1260If 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]1261class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1262
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1263<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1264
1265<pre>
1266 &lt;returntype list&gt; (&lt;parameter list&gt;)
1267</pre>
1268
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1269<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
1270specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1271which indicates that the function takes a variable number of arguments.
1272Variable argument functions can access their arguments with the <a
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1273 href="#int_varargs">variable argument handling intrinsic</a> functions.
1274'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1275<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1276
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1277<h5>Examples:</h5>
1278<table class="layout">
1279 <tr class="layout">
1280 <td class="left"><tt>i32 (i32)</tt></td>
1281 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1282 </td>
1283 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1284 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1285 </tt></td>
1286 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1287 an <tt>i16</tt> that should be sign extended and a
1288 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1289 <tt>float</tt>.
1290 </td>
1291 </tr><tr class="layout">
1292 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1293 <td class="left">A vararg function that takes at least one
1294 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1295 which returns an integer. This is the signature for <tt>printf</tt> in
1296 LLVM.
1297 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1298 </tr><tr class="layout">
1299 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Devang Patel6dddba22008-03-24 18:10:52 +0000[diff] [blame]1300 <td class="left">A function taking an <tt>i32></tt>, returning two
1301 <tt> i32 </tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1302 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1303 </tr>
1304</table>
1305
1306</div>
1307<!-- _______________________________________________________________________ -->
1308<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
1309<div class="doc_text">
1310<h5>Overview:</h5>
1311<p>The structure type is used to represent a collection of data members
1312together in memory. The packing of the field types is defined to match
1313the ABI of the underlying processor. The elements of a structure may
1314be any type that has a size.</p>
1315<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1316and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1317field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1318instruction.</p>
1319<h5>Syntax:</h5>
1320<pre> { &lt;type list&gt; }<br></pre>
1321<h5>Examples:</h5>
1322<table class="layout">
1323 <tr class="layout">
1324 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1325 <td class="left">A triple of three <tt>i32</tt> values</td>
1326 </tr><tr class="layout">
1327 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1328 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1329 second element is a <a href="#t_pointer">pointer</a> to a
1330 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1331 an <tt>i32</tt>.</td>
1332 </tr>
1333</table>
1334</div>
1335
1336<!-- _______________________________________________________________________ -->
1337<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1338</div>
1339<div class="doc_text">
1340<h5>Overview:</h5>
1341<p>The packed structure type is used to represent a collection of data members
1342together in memory. There is no padding between fields. Further, the alignment
1343of a packed structure is 1 byte. The elements of a packed structure may
1344be any type that has a size.</p>
1345<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1346and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1347field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1348instruction.</p>
1349<h5>Syntax:</h5>
1350<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1351<h5>Examples:</h5>
1352<table class="layout">
1353 <tr class="layout">
1354 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1355 <td class="left">A triple of three <tt>i32</tt> values</td>
1356 </tr><tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1357 <td class="left"><tt>&lt; { float, i32 (i32)* } &gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1358 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1359 second element is a <a href="#t_pointer">pointer</a> to a
1360 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1361 an <tt>i32</tt>.</td>
1362 </tr>
1363</table>
1364</div>
1365
1366<!-- _______________________________________________________________________ -->
1367<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
1368<div class="doc_text">
1369<h5>Overview:</h5>
1370<p>As in many languages, the pointer type represents a pointer or
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]1371reference to another object, which must live in memory. Pointer types may have
1372an optional address space attribute defining the target-specific numbered
1373address space where the pointed-to object resides. The default address space is
1374zero.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1375<h5>Syntax:</h5>
1376<pre> &lt;type&gt; *<br></pre>
1377<h5>Examples:</h5>
1378<table class="layout">
1379 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1380 <td class="left"><tt>[4x i32]*</tt></td>
1381 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1382 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1383 </tr>
1384 <tr class="layout">
1385 <td class="left"><tt>i32 (i32 *) *</tt></td>
1386 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1387 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1388 <tt>i32</tt>.</td>
1389 </tr>
1390 <tr class="layout">
1391 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1392 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1393 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1394 </tr>
1395</table>
1396</div>
1397
1398<!-- _______________________________________________________________________ -->
1399<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
1400<div class="doc_text">
1401
1402<h5>Overview:</h5>
1403
1404<p>A vector type is a simple derived type that represents a vector
1405of elements. Vector types are used when multiple primitive data
1406are operated in parallel using a single instruction (SIMD).
1407A vector type requires a size (number of
1408elements) and an underlying primitive data type. Vectors must have a power
1409of two length (1, 2, 4, 8, 16 ...). Vector types are
1410considered <a href="#t_firstclass">first class</a>.</p>
1411
1412<h5>Syntax:</h5>
1413
1414<pre>
1415 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1416</pre>
1417
1418<p>The number of elements is a constant integer value; elementtype may
1419be any integer or floating point type.</p>
1420
1421<h5>Examples:</h5>
1422
1423<table class="layout">
1424 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1425 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1426 <td class="left">Vector of 4 32-bit integer values.</td>
1427 </tr>
1428 <tr class="layout">
1429 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1430 <td class="left">Vector of 8 32-bit floating-point values.</td>
1431 </tr>
1432 <tr class="layout">
1433 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1434 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1435 </tr>
1436</table>
1437</div>
1438
1439<!-- _______________________________________________________________________ -->
1440<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1441<div class="doc_text">
1442
1443<h5>Overview:</h5>
1444
1445<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksenda0706e2007-10-14 00:34:53 +0000[diff] [blame]1446corresponds (for example) to the C notion of a forward declared structure type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1447In LLVM, opaque types can eventually be resolved to any type (not just a
1448structure type).</p>
1449
1450<h5>Syntax:</h5>
1451
1452<pre>
1453 opaque
1454</pre>
1455
1456<h5>Examples:</h5>
1457
1458<table class="layout">
1459 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1460 <td class="left"><tt>opaque</tt></td>
1461 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1462 </tr>
1463</table>
1464</div>
1465
1466
1467<!-- *********************************************************************** -->
1468<div class="doc_section"> <a name="constants">Constants</a> </div>
1469<!-- *********************************************************************** -->
1470
1471<div class="doc_text">
1472
1473<p>LLVM has several different basic types of constants. This section describes
1474them all and their syntax.</p>
1475
1476</div>
1477
1478<!-- ======================================================================= -->
1479<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1480
1481<div class="doc_text">
1482
1483<dl>
1484 <dt><b>Boolean constants</b></dt>
1485
1486 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1487 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
1488 </dd>
1489
1490 <dt><b>Integer constants</b></dt>
1491
1492 <dd>Standard integers (such as '4') are constants of the <a
1493 href="#t_integer">integer</a> type. Negative numbers may be used with
1494 integer types.
1495 </dd>
1496
1497 <dt><b>Floating point constants</b></dt>
1498
1499 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1500 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]1501 notation (see below). The assembler requires the exact decimal value of
1502 a floating-point constant. For example, the assembler accepts 1.25 but
1503 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1504 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1505
1506 <dt><b>Null pointer constants</b></dt>
1507
1508 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
1509 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1510
1511</dl>
1512
1513<p>The one non-intuitive notation for constants is the optional hexadecimal form
1514of floating point constants. For example, the form '<tt>double
15150x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
15164.5e+15</tt>'. The only time hexadecimal floating point constants are required
1517(and the only time that they are generated by the disassembler) is when a
1518floating point constant must be emitted but it cannot be represented as a
1519decimal floating point number. For example, NaN's, infinities, and other
1520special values are represented in their IEEE hexadecimal format so that
1521assembly and disassembly do not cause any bits to change in the constants.</p>
1522
1523</div>
1524
1525<!-- ======================================================================= -->
1526<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1527</div>
1528
1529<div class="doc_text">
1530<p>Aggregate constants arise from aggregation of simple constants
1531and smaller aggregate constants.</p>
1532
1533<dl>
1534 <dt><b>Structure constants</b></dt>
1535
1536 <dd>Structure constants are represented with notation similar to structure
1537 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner6c8de962007-12-25 20:34:52 +0000[diff] [blame]1538 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1539 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]1540 must have <a href="#t_struct">structure type</a>, and the number and
1541 types of elements must match those specified by the type.
1542 </dd>
1543
1544 <dt><b>Array constants</b></dt>
1545
1546 <dd>Array constants are represented with notation similar to array type
1547 definitions (a comma separated list of elements, surrounded by square brackets
1548 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
1549 constants must have <a href="#t_array">array type</a>, and the number and
1550 types of elements must match those specified by the type.
1551 </dd>
1552
1553 <dt><b>Vector constants</b></dt>
1554
1555 <dd>Vector constants are represented with notation similar to vector type
1556 definitions (a comma separated list of elements, surrounded by
1557 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1558 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
1559 href="#t_vector">vector type</a>, and the number and types of elements must
1560 match those specified by the type.
1561 </dd>
1562
1563 <dt><b>Zero initialization</b></dt>
1564
1565 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1566 value to zero of <em>any</em> type, including scalar and aggregate types.
1567 This is often used to avoid having to print large zero initializers (e.g. for
1568 large arrays) and is always exactly equivalent to using explicit zero
1569 initializers.
1570 </dd>
1571</dl>
1572
1573</div>
1574
1575<!-- ======================================================================= -->
1576<div class="doc_subsection">
1577 <a name="globalconstants">Global Variable and Function Addresses</a>
1578</div>
1579
1580<div class="doc_text">
1581
1582<p>The addresses of <a href="#globalvars">global variables</a> and <a
1583href="#functionstructure">functions</a> are always implicitly valid (link-time)
1584constants. These constants are explicitly referenced when the <a
1585href="#identifiers">identifier for the global</a> is used and always have <a
1586href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1587file:</p>
1588
1589<div class="doc_code">
1590<pre>
1591@X = global i32 17
1592@Y = global i32 42
1593@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
1594</pre>
1595</div>
1596
1597</div>
1598
1599<!-- ======================================================================= -->
1600<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
1601<div class="doc_text">
1602 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
1603 no specific value. Undefined values may be of any type and be used anywhere
1604 a constant is permitted.</p>
1605
1606 <p>Undefined values indicate to the compiler that the program is well defined
1607 no matter what value is used, giving the compiler more freedom to optimize.
1608 </p>
1609</div>
1610
1611<!-- ======================================================================= -->
1612<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1613</div>
1614
1615<div class="doc_text">
1616
1617<p>Constant expressions are used to allow expressions involving other constants
1618to be used as constants. Constant expressions may be of any <a
1619href="#t_firstclass">first class</a> type and may involve any LLVM operation
1620that does not have side effects (e.g. load and call are not supported). The
1621following is the syntax for constant expressions:</p>
1622
1623<dl>
1624 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1625 <dd>Truncate a constant to another type. The bit size of CST must be larger
1626 than the bit size of TYPE. Both types must be integers.</dd>
1627
1628 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1629 <dd>Zero extend a constant to another type. The bit size of CST must be
1630 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1631
1632 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1633 <dd>Sign extend a constant to another type. The bit size of CST must be
1634 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1635
1636 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1637 <dd>Truncate a floating point constant to another floating point type. The
1638 size of CST must be larger than the size of TYPE. Both types must be
1639 floating point.</dd>
1640
1641 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1642 <dd>Floating point extend a constant to another type. The size of CST must be
1643 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1644
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]1645 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1646 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1647 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1648 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1649 of the same number of elements. If the value won't fit in the integer type,
1650 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1651
1652 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
1653 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1654 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1655 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1656 of the same number of elements. If the value won't fit in the integer type,
1657 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1658
1659 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
1660 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1661 constant. TYPE must be a scalar or vector floating point type. CST must be of
1662 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1663 of the same number of elements. If the value won't fit in the floating point
1664 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1665
1666 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
1667 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1668 constant. TYPE must be a scalar or vector floating point type. CST must be of
1669 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1670 of the same number of elements. If the value won't fit in the floating point
1671 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1672
1673 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1674 <dd>Convert a pointer typed constant to the corresponding integer constant
1675 TYPE must be an integer type. CST must be of pointer type. The CST value is
1676 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1677
1678 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1679 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1680 pointer type. CST must be of integer type. The CST value is zero extended,
1681 truncated, or unchanged to make it fit in a pointer size. This one is
1682 <i>really</i> dangerous!</dd>
1683
1684 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
1685 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1686 identical (same number of bits). The conversion is done as if the CST value
1687 was stored to memory and read back as TYPE. In other words, no bits change
1688 with this operator, just the type. This can be used for conversion of
1689 vector types to any other type, as long as they have the same bit width. For
1690 pointers it is only valid to cast to another pointer type.
1691 </dd>
1692
1693 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1694
1695 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1696 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1697 instruction, the index list may have zero or more indexes, which are required
1698 to make sense for the type of "CSTPTR".</dd>
1699
1700 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1701
1702 <dd>Perform the <a href="#i_select">select operation</a> on
1703 constants.</dd>
1704
1705 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1706 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1707
1708 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1709 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
1710
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]1711 <dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
1712 <dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
1713
1714 <dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
1715 <dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
1716
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1717 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1718
1719 <dd>Perform the <a href="#i_extractelement">extractelement
1720 operation</a> on constants.
1721
1722 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1723
1724 <dd>Perform the <a href="#i_insertelement">insertelement
1725 operation</a> on constants.</dd>
1726
1727
1728 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1729
1730 <dd>Perform the <a href="#i_shufflevector">shufflevector
1731 operation</a> on constants.</dd>
1732
1733 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1734
1735 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1736 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
1737 binary</a> operations. The constraints on operands are the same as those for
1738 the corresponding instruction (e.g. no bitwise operations on floating point
1739 values are allowed).</dd>
1740</dl>
1741</div>
1742
1743<!-- *********************************************************************** -->
1744<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1745<!-- *********************************************************************** -->
1746
1747<!-- ======================================================================= -->
1748<div class="doc_subsection">
1749<a name="inlineasm">Inline Assembler Expressions</a>
1750</div>
1751
1752<div class="doc_text">
1753
1754<p>
1755LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1756Module-Level Inline Assembly</a>) through the use of a special value. This
1757value represents the inline assembler as a string (containing the instructions
1758to emit), a list of operand constraints (stored as a string), and a flag that
1759indicates whether or not the inline asm expression has side effects. An example
1760inline assembler expression is:
1761</p>
1762
1763<div class="doc_code">
1764<pre>
1765i32 (i32) asm "bswap $0", "=r,r"
1766</pre>
1767</div>
1768
1769<p>
1770Inline assembler expressions may <b>only</b> be used as the callee operand of
1771a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1772</p>
1773
1774<div class="doc_code">
1775<pre>
1776%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
1777</pre>
1778</div>
1779
1780<p>
1781Inline asms with side effects not visible in the constraint list must be marked
1782as having side effects. This is done through the use of the
1783'<tt>sideeffect</tt>' keyword, like so:
1784</p>
1785
1786<div class="doc_code">
1787<pre>
1788call void asm sideeffect "eieio", ""()
1789</pre>
1790</div>
1791
1792<p>TODO: The format of the asm and constraints string still need to be
1793documented here. Constraints on what can be done (e.g. duplication, moving, etc
1794need to be documented).
1795</p>
1796
1797</div>
1798
1799<!-- *********************************************************************** -->
1800<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1801<!-- *********************************************************************** -->
1802
1803<div class="doc_text">
1804
1805<p>The LLVM instruction set consists of several different
1806classifications of instructions: <a href="#terminators">terminator
1807instructions</a>, <a href="#binaryops">binary instructions</a>,
1808<a href="#bitwiseops">bitwise binary instructions</a>, <a
1809 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1810instructions</a>.</p>
1811
1812</div>
1813
1814<!-- ======================================================================= -->
1815<div class="doc_subsection"> <a name="terminators">Terminator
1816Instructions</a> </div>
1817
1818<div class="doc_text">
1819
1820<p>As mentioned <a href="#functionstructure">previously</a>, every
1821basic block in a program ends with a "Terminator" instruction, which
1822indicates which block should be executed after the current block is
1823finished. These terminator instructions typically yield a '<tt>void</tt>'
1824value: they produce control flow, not values (the one exception being
1825the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
1826<p>There are six different terminator instructions: the '<a
1827 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1828instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
1829the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1830 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1831 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
1832
1833</div>
1834
1835<!-- _______________________________________________________________________ -->
1836<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1837Instruction</a> </div>
1838<div class="doc_text">
1839<h5>Syntax:</h5>
1840<pre> ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
1841 ret void <i>; Return from void function</i>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1842 ret &lt;type&gt; &lt;value&gt;, &lt;type&gt; &lt;value&gt; <i>; Return two values from a non-void function </i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1843</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1844
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1845<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1846
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1847<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
1848value) from a function back to the caller.</p>
1849<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1850returns value(s) and then causes control flow, and one that just causes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1851control flow to occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1852
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1853<h5>Arguments:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1854
1855<p>The '<tt>ret</tt>' instruction may return zero, one or multiple values.
1856The type of each return value must be a '<a href="#t_firstclass">first
1857class</a>' type. Note that a function is not <a href="#wellformed">well
1858formed</a> if there exists a '<tt>ret</tt>' instruction inside of the
1859function that returns values that do not match the return type of the
1860function.</p>
1861
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1862<h5>Semantics:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1863
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1864<p>When the '<tt>ret</tt>' instruction is executed, control flow
1865returns back to the calling function's context. If the caller is a "<a
1866 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
1867the instruction after the call. If the caller was an "<a
1868 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
1869at the beginning of the "normal" destination block. If the instruction
1870returns a value, that value shall set the call or invoke instruction's
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1871return value. If the instruction returns multiple values then these
Devang Patelec8a5b02008-03-11 05:51:59 +0000[diff] [blame]1872values can only be accessed through a '<a href="#i_getresult"><tt>getresult</tt>
1873</a>' instruction.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1874
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1875<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1876
1877<pre>
1878 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1879 ret void <i>; Return from a void function</i>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1880 ret i32 4, i8 2 <i>; Return two values 4 and 2 </i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1881</pre>
1882</div>
1883<!-- _______________________________________________________________________ -->
1884<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
1885<div class="doc_text">
1886<h5>Syntax:</h5>
1887<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
1888</pre>
1889<h5>Overview:</h5>
1890<p>The '<tt>br</tt>' instruction is used to cause control flow to
1891transfer to a different basic block in the current function. There are
1892two forms of this instruction, corresponding to a conditional branch
1893and an unconditional branch.</p>
1894<h5>Arguments:</h5>
1895<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
1896single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
1897unconditional form of the '<tt>br</tt>' instruction takes a single
1898'<tt>label</tt>' value as a target.</p>
1899<h5>Semantics:</h5>
1900<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
1901argument is evaluated. If the value is <tt>true</tt>, control flows
1902to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1903control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
1904<h5>Example:</h5>
1905<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
1906 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
1907</div>
1908<!-- _______________________________________________________________________ -->
1909<div class="doc_subsubsection">
1910 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1911</div>
1912
1913<div class="doc_text">
1914<h5>Syntax:</h5>
1915
1916<pre>
1917 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1918</pre>
1919
1920<h5>Overview:</h5>
1921
1922<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1923several different places. It is a generalization of the '<tt>br</tt>'
1924instruction, allowing a branch to occur to one of many possible
1925destinations.</p>
1926
1927
1928<h5>Arguments:</h5>
1929
1930<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1931comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1932an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1933table is not allowed to contain duplicate constant entries.</p>
1934
1935<h5>Semantics:</h5>
1936
1937<p>The <tt>switch</tt> instruction specifies a table of values and
1938destinations. When the '<tt>switch</tt>' instruction is executed, this
1939table is searched for the given value. If the value is found, control flow is
1940transfered to the corresponding destination; otherwise, control flow is
1941transfered to the default destination.</p>
1942
1943<h5>Implementation:</h5>
1944
1945<p>Depending on properties of the target machine and the particular
1946<tt>switch</tt> instruction, this instruction may be code generated in different
1947ways. For example, it could be generated as a series of chained conditional
1948branches or with a lookup table.</p>
1949
1950<h5>Example:</h5>
1951
1952<pre>
1953 <i>; Emulate a conditional br instruction</i>
1954 %Val = <a href="#i_zext">zext</a> i1 %value to i32
1955 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
1956
1957 <i>; Emulate an unconditional br instruction</i>
1958 switch i32 0, label %dest [ ]
1959
1960 <i>; Implement a jump table:</i>
1961 switch i32 %val, label %otherwise [ i32 0, label %onzero
1962 i32 1, label %onone
1963 i32 2, label %ontwo ]
1964</pre>
1965</div>
1966
1967<!-- _______________________________________________________________________ -->
1968<div class="doc_subsubsection">
1969 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1970</div>
1971
1972<div class="doc_text">
1973
1974<h5>Syntax:</h5>
1975
1976<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]1977 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] &lt;ptr to function ty&gt; &lt;function ptr val&gt;(&lt;function args&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1978 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
1979</pre>
1980
1981<h5>Overview:</h5>
1982
1983<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1984function, with the possibility of control flow transfer to either the
1985'<tt>normal</tt>' label or the
1986'<tt>exception</tt>' label. If the callee function returns with the
1987"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1988"normal" label. If the callee (or any indirect callees) returns with the "<a
1989href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1990continued at the dynamically nearest "exception" label. If the callee function
Devang Patelec8a5b02008-03-11 05:51:59 +0000[diff] [blame]1991returns multiple values then individual return values are only accessible through
1992a '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1993
1994<h5>Arguments:</h5>
1995
1996<p>This instruction requires several arguments:</p>
1997
1998<ol>
1999 <li>
2000 The optional "cconv" marker indicates which <a href="#callingconv">calling
2001 convention</a> the call should use. If none is specified, the call defaults
2002 to using C calling conventions.
2003 </li>
2004 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
2005 function value being invoked. In most cases, this is a direct function
2006 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
2007 an arbitrary pointer to function value.
2008 </li>
2009
2010 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
2011 function to be invoked. </li>
2012
2013 <li>'<tt>function args</tt>': argument list whose types match the function
2014 signature argument types. If the function signature indicates the function
2015 accepts a variable number of arguments, the extra arguments can be
2016 specified. </li>
2017
2018 <li>'<tt>normal label</tt>': the label reached when the called function
2019 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2020
2021 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2022 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2023
2024</ol>
2025
2026<h5>Semantics:</h5>
2027
2028<p>This instruction is designed to operate as a standard '<tt><a
2029href="#i_call">call</a></tt>' instruction in most regards. The primary
2030difference is that it establishes an association with a label, which is used by
2031the runtime library to unwind the stack.</p>
2032
2033<p>This instruction is used in languages with destructors to ensure that proper
2034cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2035exception. Additionally, this is important for implementation of
2036'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2037
2038<h5>Example:</h5>
2039<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2040 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2041 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2042 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2043 unwind label %TestCleanup <i>; {i32}:retval set</i>
2044</pre>
2045</div>
2046
2047
2048<!-- _______________________________________________________________________ -->
2049
2050<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2051Instruction</a> </div>
2052
2053<div class="doc_text">
2054
2055<h5>Syntax:</h5>
2056<pre>
2057 unwind
2058</pre>
2059
2060<h5>Overview:</h5>
2061
2062<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2063at the first callee in the dynamic call stack which used an <a
2064href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2065primarily used to implement exception handling.</p>
2066
2067<h5>Semantics:</h5>
2068
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2069<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2070immediately halt. The dynamic call stack is then searched for the first <a
2071href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2072execution continues at the "exceptional" destination block specified by the
2073<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2074dynamic call chain, undefined behavior results.</p>
2075</div>
2076
2077<!-- _______________________________________________________________________ -->
2078
2079<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2080Instruction</a> </div>
2081
2082<div class="doc_text">
2083
2084<h5>Syntax:</h5>
2085<pre>
2086 unreachable
2087</pre>
2088
2089<h5>Overview:</h5>
2090
2091<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2092instruction is used to inform the optimizer that a particular portion of the
2093code is not reachable. This can be used to indicate that the code after a
2094no-return function cannot be reached, and other facts.</p>
2095
2096<h5>Semantics:</h5>
2097
2098<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2099</div>
2100
2101
2102
2103<!-- ======================================================================= -->
2104<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
2105<div class="doc_text">
2106<p>Binary operators are used to do most of the computation in a
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2107program. They require two operands of the same type, execute an operation on them, and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2108produce a single value. The operands might represent
2109multiple 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]2110The result value has the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2111<p>There are several different binary operators:</p>
2112</div>
2113<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2114<div class="doc_subsubsection">
2115 <a name="i_add">'<tt>add</tt>' Instruction</a>
2116</div>
2117
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2118<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2119
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2120<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2121
2122<pre>
2123 &lt;result&gt; = add &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2124</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2125
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2126<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2127
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2128<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2129
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2130<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2131
2132<p>The two arguments to the '<tt>add</tt>' instruction must be <a
2133 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
2134 <a href="#t_vector">vector</a> values. Both arguments must have identical
2135 types.</p>
2136
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2137<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2138
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2139<p>The value produced is the integer or floating point sum of the two
2140operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2141
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2142<p>If an integer sum has unsigned overflow, the result returned is the
2143mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2144the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2145
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2146<p>Because LLVM integers use a two's complement representation, this
2147instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2148
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2149<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2150
2151<pre>
2152 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2153</pre>
2154</div>
2155<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2156<div class="doc_subsubsection">
2157 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2158</div>
2159
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2160<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2161
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2162<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2163
2164<pre>
2165 &lt;result&gt; = sub &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2166</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2167
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2168<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2169
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2170<p>The '<tt>sub</tt>' instruction returns the difference of its two
2171operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2172
2173<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2174'<tt>neg</tt>' instruction present in most other intermediate
2175representations.</p>
2176
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2177<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2178
2179<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
2180 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2181 or <a href="#t_vector">vector</a> values. Both arguments must have identical
2182 types.</p>
2183
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2184<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2185
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2186<p>The value produced is the integer or floating point difference of
2187the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2188
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2189<p>If an integer difference has unsigned overflow, the result returned is the
2190mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2191the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2192
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2193<p>Because LLVM integers use a two's complement representation, this
2194instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2195
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2196<h5>Example:</h5>
2197<pre>
2198 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2199 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2200</pre>
2201</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2202
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2203<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2204<div class="doc_subsubsection">
2205 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2206</div>
2207
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2208<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2209
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2210<h5>Syntax:</h5>
2211<pre> &lt;result&gt; = mul &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2212</pre>
2213<h5>Overview:</h5>
2214<p>The '<tt>mul</tt>' instruction returns the product of its two
2215operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2216
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2217<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2218
2219<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
2220href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2221or <a href="#t_vector">vector</a> values. Both arguments must have identical
2222types.</p>
2223
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2224<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2225
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2226<p>The value produced is the integer or floating point product of the
2227two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2228
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2229<p>If the result of an integer multiplication has unsigned overflow,
2230the result returned is the mathematical result modulo
22312<sup>n</sup>, where n is the bit width of the result.</p>
2232<p>Because LLVM integers use a two's complement representation, and the
2233result is the same width as the operands, this instruction returns the
2234correct result for both signed and unsigned integers. If a full product
2235(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2236should be sign-extended or zero-extended as appropriate to the
2237width of the full product.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2238<h5>Example:</h5>
2239<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
2240</pre>
2241</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2242
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2243<!-- _______________________________________________________________________ -->
2244<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2245</a></div>
2246<div class="doc_text">
2247<h5>Syntax:</h5>
2248<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2249</pre>
2250<h5>Overview:</h5>
2251<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2252operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2253
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2254<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2255
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2256<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2257<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2258values. Both arguments must have identical types.</p>
2259
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2260<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2261
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2262<p>The value produced is the unsigned integer quotient of the two operands.</p>
2263<p>Note that unsigned integer division and signed integer division are distinct
2264operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2265<p>Division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2266<h5>Example:</h5>
2267<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2268</pre>
2269</div>
2270<!-- _______________________________________________________________________ -->
2271<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2272</a> </div>
2273<div class="doc_text">
2274<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2275<pre>
2276 &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2277</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2278
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2279<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2280
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2281<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2282operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2283
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2284<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2285
2286<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2287<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2288values. Both arguments must have identical types.</p>
2289
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2290<h5>Semantics:</h5>
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2291<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]2292<p>Note that signed integer division and unsigned integer division are distinct
2293operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2294<p>Division by zero leads to undefined behavior. Overflow also leads to
2295undefined behavior; this is a rare case, but can occur, for example,
2296by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2297<h5>Example:</h5>
2298<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2299</pre>
2300</div>
2301<!-- _______________________________________________________________________ -->
2302<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2303Instruction</a> </div>
2304<div class="doc_text">
2305<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2306<pre>
2307 &lt;result&gt; = fdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2308</pre>
2309<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2310
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2311<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
2312operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2313
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2314<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2315
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2316<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2317<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2318of floating point values. Both arguments must have identical types.</p>
2319
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2320<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2321
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2322<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2323
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2324<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2325
2326<pre>
2327 &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]2328</pre>
2329</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2330
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2331<!-- _______________________________________________________________________ -->
2332<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2333</div>
2334<div class="doc_text">
2335<h5>Syntax:</h5>
2336<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2337</pre>
2338<h5>Overview:</h5>
2339<p>The '<tt>urem</tt>' instruction returns the remainder from the
2340unsigned division of its two arguments.</p>
2341<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2342<p>The two arguments to the '<tt>urem</tt>' instruction must be
2343<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2344values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2345<h5>Semantics:</h5>
2346<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2347This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2348<p>Note that unsigned integer remainder and signed integer remainder are
2349distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2350<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2351<h5>Example:</h5>
2352<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2353</pre>
2354
2355</div>
2356<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2357<div class="doc_subsubsection">
2358 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2359</div>
2360
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2361<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2362
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2363<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2364
2365<pre>
2366 &lt;result&gt; = srem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2367</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2368
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2369<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2370
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2371<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman3e3fd8c2007-11-05 23:35:22 +0000[diff] [blame]2372signed division of its two operands. This instruction can also take
2373<a href="#t_vector">vector</a> versions of the values in which case
2374the elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]2375
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2376<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2377
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2378<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2379<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2380values. Both arguments must have identical types.</p>
2381
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2382<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2383
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2384<p>This instruction returns the <i>remainder</i> of a division (where the result
2385has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2386operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2387a value. For more information about the difference, see <a
2388 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2389Math Forum</a>. For a table of how this is implemented in various languages,
2390please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
2391Wikipedia: modulo operation</a>.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2392<p>Note that signed integer remainder and unsigned integer remainder are
2393distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2394<p>Taking the remainder of a division by zero leads to undefined behavior.
2395Overflow also leads to undefined behavior; this is a rare case, but can occur,
2396for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2397(The remainder doesn't actually overflow, but this rule lets srem be
2398implemented using instructions that return both the result of the division
2399and the remainder.)</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2400<h5>Example:</h5>
2401<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2402</pre>
2403
2404</div>
2405<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2406<div class="doc_subsubsection">
2407 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2408
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2409<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2410
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2411<h5>Syntax:</h5>
2412<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2413</pre>
2414<h5>Overview:</h5>
2415<p>The '<tt>frem</tt>' instruction returns the remainder from the
2416division of its two operands.</p>
2417<h5>Arguments:</h5>
2418<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2419<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2420of floating point values. Both arguments must have identical types.</p>
2421
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2422<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2423
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2424<p>This instruction returns the <i>remainder</i> of a division.
2425The remainder has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2426
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2427<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2428
2429<pre>
2430 &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]2431</pre>
2432</div>
2433
2434<!-- ======================================================================= -->
2435<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2436Operations</a> </div>
2437<div class="doc_text">
2438<p>Bitwise binary operators are used to do various forms of
2439bit-twiddling in a program. They are generally very efficient
2440instructions and can commonly be strength reduced from other
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2441instructions. They require two operands of the same type, execute an operation on them,
2442and 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]2443</div>
2444
2445<!-- _______________________________________________________________________ -->
2446<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2447Instruction</a> </div>
2448<div class="doc_text">
2449<h5>Syntax:</h5>
2450<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2451</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2452
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2453<h5>Overview:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2454
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2455<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2456the left a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2457
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2458<h5>Arguments:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2459
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2460<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2461 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2462type. '<tt>var2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2463
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2464<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2465
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2466<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup> mod 2<sup>n</sup>,
2467where n is the width of the result. If <tt>var2</tt> is (statically or dynamically) negative or
2468equal to or larger than the number of bits in <tt>var1</tt>, the result is undefined.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2469
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2470<h5>Example:</h5><pre>
2471 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2472 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2473 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2474 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2475</pre>
2476</div>
2477<!-- _______________________________________________________________________ -->
2478<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2479Instruction</a> </div>
2480<div class="doc_text">
2481<h5>Syntax:</h5>
2482<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2483</pre>
2484
2485<h5>Overview:</h5>
2486<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2487operand shifted to the right a specified number of bits with zero fill.</p>
2488
2489<h5>Arguments:</h5>
2490<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2491<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2492type. '<tt>var2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2493
2494<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2495
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2496<p>This instruction always performs a logical shift right operation. The most
2497significant bits of the result will be filled with zero bits after the
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2498shift. If <tt>var2</tt> is (statically or dynamically) equal to or larger than
2499the number of bits in <tt>var1</tt>, the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2500
2501<h5>Example:</h5>
2502<pre>
2503 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2504 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2505 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2506 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2507 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2508</pre>
2509</div>
2510
2511<!-- _______________________________________________________________________ -->
2512<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2513Instruction</a> </div>
2514<div class="doc_text">
2515
2516<h5>Syntax:</h5>
2517<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2518</pre>
2519
2520<h5>Overview:</h5>
2521<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2522operand shifted to the right a specified number of bits with sign extension.</p>
2523
2524<h5>Arguments:</h5>
2525<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2526<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2527type. '<tt>var2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2528
2529<h5>Semantics:</h5>
2530<p>This instruction always performs an arithmetic shift right operation,
2531The most significant bits of the result will be filled with the sign bit
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2532of <tt>var1</tt>. If <tt>var2</tt> is (statically or dynamically) equal to or
2533larger than the number of bits in <tt>var1</tt>, the result is undefined.
2534</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2535
2536<h5>Example:</h5>
2537<pre>
2538 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2539 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2540 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2541 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2542 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2543</pre>
2544</div>
2545
2546<!-- _______________________________________________________________________ -->
2547<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2548Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2549
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2550<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2551
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2552<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2553
2554<pre>
2555 &lt;result&gt; = and &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2556</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2557
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2558<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2559
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2560<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2561its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2562
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2563<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2564
2565<p>The two arguments to the '<tt>and</tt>' instruction must be
2566<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2567values. Both arguments must have identical types.</p>
2568
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2569<h5>Semantics:</h5>
2570<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
2571<p> </p>
2572<div style="align: center">
2573<table border="1" cellspacing="0" cellpadding="4">
2574 <tbody>
2575 <tr>
2576 <td>In0</td>
2577 <td>In1</td>
2578 <td>Out</td>
2579 </tr>
2580 <tr>
2581 <td>0</td>
2582 <td>0</td>
2583 <td>0</td>
2584 </tr>
2585 <tr>
2586 <td>0</td>
2587 <td>1</td>
2588 <td>0</td>
2589 </tr>
2590 <tr>
2591 <td>1</td>
2592 <td>0</td>
2593 <td>0</td>
2594 </tr>
2595 <tr>
2596 <td>1</td>
2597 <td>1</td>
2598 <td>1</td>
2599 </tr>
2600 </tbody>
2601</table>
2602</div>
2603<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2604<pre>
2605 &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]2606 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2607 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
2608</pre>
2609</div>
2610<!-- _______________________________________________________________________ -->
2611<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
2612<div class="doc_text">
2613<h5>Syntax:</h5>
2614<pre> &lt;result&gt; = or &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2615</pre>
2616<h5>Overview:</h5>
2617<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2618or of its two operands.</p>
2619<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2620
2621<p>The two arguments to the '<tt>or</tt>' instruction must be
2622<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2623values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2624<h5>Semantics:</h5>
2625<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
2626<p> </p>
2627<div style="align: center">
2628<table border="1" cellspacing="0" cellpadding="4">
2629 <tbody>
2630 <tr>
2631 <td>In0</td>
2632 <td>In1</td>
2633 <td>Out</td>
2634 </tr>
2635 <tr>
2636 <td>0</td>
2637 <td>0</td>
2638 <td>0</td>
2639 </tr>
2640 <tr>
2641 <td>0</td>
2642 <td>1</td>
2643 <td>1</td>
2644 </tr>
2645 <tr>
2646 <td>1</td>
2647 <td>0</td>
2648 <td>1</td>
2649 </tr>
2650 <tr>
2651 <td>1</td>
2652 <td>1</td>
2653 <td>1</td>
2654 </tr>
2655 </tbody>
2656</table>
2657</div>
2658<h5>Example:</h5>
2659<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2660 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2661 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
2662</pre>
2663</div>
2664<!-- _______________________________________________________________________ -->
2665<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2666Instruction</a> </div>
2667<div class="doc_text">
2668<h5>Syntax:</h5>
2669<pre> &lt;result&gt; = xor &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2670</pre>
2671<h5>Overview:</h5>
2672<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2673or of its two operands. The <tt>xor</tt> is used to implement the
2674"one's complement" operation, which is the "~" operator in C.</p>
2675<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2676<p>The two arguments to the '<tt>xor</tt>' instruction must be
2677<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2678values. Both arguments must have identical types.</p>
2679
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2680<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2681
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2682<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
2683<p> </p>
2684<div style="align: center">
2685<table border="1" cellspacing="0" cellpadding="4">
2686 <tbody>
2687 <tr>
2688 <td>In0</td>
2689 <td>In1</td>
2690 <td>Out</td>
2691 </tr>
2692 <tr>
2693 <td>0</td>
2694 <td>0</td>
2695 <td>0</td>
2696 </tr>
2697 <tr>
2698 <td>0</td>
2699 <td>1</td>
2700 <td>1</td>
2701 </tr>
2702 <tr>
2703 <td>1</td>
2704 <td>0</td>
2705 <td>1</td>
2706 </tr>
2707 <tr>
2708 <td>1</td>
2709 <td>1</td>
2710 <td>0</td>
2711 </tr>
2712 </tbody>
2713</table>
2714</div>
2715<p> </p>
2716<h5>Example:</h5>
2717<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2718 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2719 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2720 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
2721</pre>
2722</div>
2723
2724<!-- ======================================================================= -->
2725<div class="doc_subsection">
2726 <a name="vectorops">Vector Operations</a>
2727</div>
2728
2729<div class="doc_text">
2730
2731<p>LLVM supports several instructions to represent vector operations in a
2732target-independent manner. These instructions cover the element-access and
2733vector-specific operations needed to process vectors effectively. While LLVM
2734does directly support these vector operations, many sophisticated algorithms
2735will want to use target-specific intrinsics to take full advantage of a specific
2736target.</p>
2737
2738</div>
2739
2740<!-- _______________________________________________________________________ -->
2741<div class="doc_subsubsection">
2742 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2743</div>
2744
2745<div class="doc_text">
2746
2747<h5>Syntax:</h5>
2748
2749<pre>
2750 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
2751</pre>
2752
2753<h5>Overview:</h5>
2754
2755<p>
2756The '<tt>extractelement</tt>' instruction extracts a single scalar
2757element from a vector at a specified index.
2758</p>
2759
2760
2761<h5>Arguments:</h5>
2762
2763<p>
2764The first operand of an '<tt>extractelement</tt>' instruction is a
2765value of <a href="#t_vector">vector</a> type. The second operand is
2766an index indicating the position from which to extract the element.
2767The index may be a variable.</p>
2768
2769<h5>Semantics:</h5>
2770
2771<p>
2772The result is a scalar of the same type as the element type of
2773<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2774<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2775results are undefined.
2776</p>
2777
2778<h5>Example:</h5>
2779
2780<pre>
2781 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
2782</pre>
2783</div>
2784
2785
2786<!-- _______________________________________________________________________ -->
2787<div class="doc_subsubsection">
2788 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2789</div>
2790
2791<div class="doc_text">
2792
2793<h5>Syntax:</h5>
2794
2795<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]2796 &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]2797</pre>
2798
2799<h5>Overview:</h5>
2800
2801<p>
2802The '<tt>insertelement</tt>' instruction inserts a scalar
2803element into a vector at a specified index.
2804</p>
2805
2806
2807<h5>Arguments:</h5>
2808
2809<p>
2810The first operand of an '<tt>insertelement</tt>' instruction is a
2811value of <a href="#t_vector">vector</a> type. The second operand is a
2812scalar value whose type must equal the element type of the first
2813operand. The third operand is an index indicating the position at
2814which to insert the value. The index may be a variable.</p>
2815
2816<h5>Semantics:</h5>
2817
2818<p>
2819The result is a vector of the same type as <tt>val</tt>. Its
2820element values are those of <tt>val</tt> except at position
2821<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2822exceeds the length of <tt>val</tt>, the results are undefined.
2823</p>
2824
2825<h5>Example:</h5>
2826
2827<pre>
2828 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
2829</pre>
2830</div>
2831
2832<!-- _______________________________________________________________________ -->
2833<div class="doc_subsubsection">
2834 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2835</div>
2836
2837<div class="doc_text">
2838
2839<h5>Syntax:</h5>
2840
2841<pre>
2842 &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;n x i32&gt; &lt;mask&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
2843</pre>
2844
2845<h5>Overview:</h5>
2846
2847<p>
2848The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2849from two input vectors, returning a vector of the same type.
2850</p>
2851
2852<h5>Arguments:</h5>
2853
2854<p>
2855The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2856with types that match each other and types that match the result of the
2857instruction. The third argument is a shuffle mask, which has the same number
2858of elements as the other vector type, but whose element type is always 'i32'.
2859</p>
2860
2861<p>
2862The shuffle mask operand is required to be a constant vector with either
2863constant integer or undef values.
2864</p>
2865
2866<h5>Semantics:</h5>
2867
2868<p>
2869The elements of the two input vectors are numbered from left to right across
2870both of the vectors. The shuffle mask operand specifies, for each element of
2871the result vector, which element of the two input registers the result element
2872gets. The element selector may be undef (meaning "don't care") and the second
2873operand may be undef if performing a shuffle from only one vector.
2874</p>
2875
2876<h5>Example:</h5>
2877
2878<pre>
2879 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
2880 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
2881 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2882 &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.
2883</pre>
2884</div>
2885
2886
2887<!-- ======================================================================= -->
2888<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2889 <a name="aggregateops">Aggregate Operations</a>
2890</div>
2891
2892<div class="doc_text">
2893
2894<p>LLVM supports several instructions for working with aggregate values.
2895</p>
2896
2897</div>
2898
2899<!-- _______________________________________________________________________ -->
2900<div class="doc_subsubsection">
2901 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
2902</div>
2903
2904<div class="doc_text">
2905
2906<h5>Syntax:</h5>
2907
2908<pre>
2909 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
2910</pre>
2911
2912<h5>Overview:</h5>
2913
2914<p>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]2915The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
2916or array element from an aggregate value.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2917</p>
2918
2919
2920<h5>Arguments:</h5>
2921
2922<p>
2923The first operand of an '<tt>extractvalue</tt>' instruction is a
2924value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]2925type. The operands are constant indices to specify which value to extract
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]2926in a similar manner as indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2927'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2928</p>
2929
2930<h5>Semantics:</h5>
2931
2932<p>
2933The result is the value at the position in the aggregate specified by
2934the index operands.
2935</p>
2936
2937<h5>Example:</h5>
2938
2939<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]2940 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2941</pre>
2942</div>
2943
2944
2945<!-- _______________________________________________________________________ -->
2946<div class="doc_subsubsection">
2947 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
2948</div>
2949
2950<div class="doc_text">
2951
2952<h5>Syntax:</h5>
2953
2954<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]2955 &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]2956</pre>
2957
2958<h5>Overview:</h5>
2959
2960<p>
2961The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]2962into a struct field or array element in an aggregate.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2963</p>
2964
2965
2966<h5>Arguments:</h5>
2967
2968<p>
2969The first operand of an '<tt>insertvalue</tt>' instruction is a
2970value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
2971The second operand is a first-class value to insert.
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]2972The following operands are constant indices
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]2973indicating the position at which to insert the value in a similar manner as
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]2974indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2975'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2976The value to insert must have the same type as the value identified
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]2977by the indices.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2978
2979<h5>Semantics:</h5>
2980
2981<p>
2982The result is an aggregate of the same type as <tt>val</tt>. Its
2983value is that of <tt>val</tt> except that the value at the position
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]2984specified by the indices is that of <tt>elt</tt>.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2985</p>
2986
2987<h5>Example:</h5>
2988
2989<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]2990 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2991</pre>
2992</div>
2993
2994
2995<!-- ======================================================================= -->
2996<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2997 <a name="memoryops">Memory Access and Addressing Operations</a>
2998</div>
2999
3000<div class="doc_text">
3001
3002<p>A key design point of an SSA-based representation is how it
3003represents memory. In LLVM, no memory locations are in SSA form, which
3004makes things very simple. This section describes how to read, write,
3005allocate, and free memory in LLVM.</p>
3006
3007</div>
3008
3009<!-- _______________________________________________________________________ -->
3010<div class="doc_subsubsection">
3011 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3012</div>
3013
3014<div class="doc_text">
3015
3016<h5>Syntax:</h5>
3017
3018<pre>
3019 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3020</pre>
3021
3022<h5>Overview:</h5>
3023
3024<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3025heap and returns a pointer to it. The object is always allocated in the generic
3026address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3027
3028<h5>Arguments:</h5>
3029
3030<p>The '<tt>malloc</tt>' instruction allocates
3031<tt>sizeof(&lt;type&gt;)*NumElements</tt>
3032bytes of memory from the operating system and returns a pointer of the
3033appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3034number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3035If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3036be aligned to at least that boundary. If not specified, or if zero, the target can
3037choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3038
3039<p>'<tt>type</tt>' must be a sized type.</p>
3040
3041<h5>Semantics:</h5>
3042
3043<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3044a pointer is returned. The result of a zero byte allocattion is undefined. The
3045result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3046
3047<h5>Example:</h5>
3048
3049<pre>
3050 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
3051
3052 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3053 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3054 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3055 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3056 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3057</pre>
3058</div>
3059
3060<!-- _______________________________________________________________________ -->
3061<div class="doc_subsubsection">
3062 <a name="i_free">'<tt>free</tt>' Instruction</a>
3063</div>
3064
3065<div class="doc_text">
3066
3067<h5>Syntax:</h5>
3068
3069<pre>
3070 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
3071</pre>
3072
3073<h5>Overview:</h5>
3074
3075<p>The '<tt>free</tt>' instruction returns memory back to the unused
3076memory heap to be reallocated in the future.</p>
3077
3078<h5>Arguments:</h5>
3079
3080<p>'<tt>value</tt>' shall be a pointer value that points to a value
3081that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3082instruction.</p>
3083
3084<h5>Semantics:</h5>
3085
3086<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner329d6532008-04-19 22:41:32 +0000[diff] [blame]3087after this instruction executes. If the pointer is null, the operation
3088is a noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3089
3090<h5>Example:</h5>
3091
3092<pre>
3093 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
3094 free [4 x i8]* %array
3095</pre>
3096</div>
3097
3098<!-- _______________________________________________________________________ -->
3099<div class="doc_subsubsection">
3100 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3101</div>
3102
3103<div class="doc_text">
3104
3105<h5>Syntax:</h5>
3106
3107<pre>
3108 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3109</pre>
3110
3111<h5>Overview:</h5>
3112
3113<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3114currently executing function, to be automatically released when this function
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3115returns to its caller. The object is always allocated in the generic address
3116space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3117
3118<h5>Arguments:</h5>
3119
3120<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
3121bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3122appropriate type to the program. If "NumElements" is specified, it is the
3123number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3124If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3125to be aligned to at least that boundary. If not specified, or if zero, the target
3126can choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3127
3128<p>'<tt>type</tt>' may be any sized type.</p>
3129
3130<h5>Semantics:</h5>
3131
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3132<p>Memory is allocated; a pointer is returned. The operation is undefiend if
3133there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3134memory is automatically released when the function returns. The '<tt>alloca</tt>'
3135instruction is commonly used to represent automatic variables that must
3136have an address available. When the function returns (either with the <tt><a
3137 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]3138instructions), the memory is reclaimed. Allocating zero bytes
3139is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3140
3141<h5>Example:</h5>
3142
3143<pre>
3144 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3145 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3146 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3147 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
3148</pre>
3149</div>
3150
3151<!-- _______________________________________________________________________ -->
3152<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3153Instruction</a> </div>
3154<div class="doc_text">
3155<h5>Syntax:</h5>
3156<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>
3157<h5>Overview:</h5>
3158<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
3159<h5>Arguments:</h5>
3160<p>The argument to the '<tt>load</tt>' instruction specifies the memory
3161address from which to load. The pointer must point to a <a
3162 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3163marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
3164the number or order of execution of this <tt>load</tt> with other
3165volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3166instructions. </p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3167<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3168The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3169(that is, the alignment of the memory address). A value of 0 or an
3170omitted "align" argument means that the operation has the preferential
3171alignment for the target. It is the responsibility of the code emitter
3172to ensure that the alignment information is correct. Overestimating
3173the alignment results in an undefined behavior. Underestimating the
3174alignment may produce less efficient code. An alignment of 1 is always
3175safe.
3176</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3177<h5>Semantics:</h5>
3178<p>The location of memory pointed to is loaded.</p>
3179<h5>Examples:</h5>
3180<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3181 <a
3182 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3183 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3184</pre>
3185</div>
3186<!-- _______________________________________________________________________ -->
3187<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3188Instruction</a> </div>
3189<div class="doc_text">
3190<h5>Syntax:</h5>
3191<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3192 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3193</pre>
3194<h5>Overview:</h5>
3195<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
3196<h5>Arguments:</h5>
3197<p>There are two arguments to the '<tt>store</tt>' instruction: a value
3198to 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]3199operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3200of the '<tt>&lt;value&gt;</tt>'
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3201operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
3202optimizer is not allowed to modify the number or order of execution of
3203this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3204 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3205<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3206The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3207(that is, the alignment of the memory address). A value of 0 or an
3208omitted "align" argument means that the operation has the preferential
3209alignment for the target. It is the responsibility of the code emitter
3210to ensure that the alignment information is correct. Overestimating
3211the alignment results in an undefined behavior. Underestimating the
3212alignment may produce less efficient code. An alignment of 1 is always
3213safe.
3214</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3215<h5>Semantics:</h5>
3216<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
3217at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
3218<h5>Example:</h5>
3219<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3220 store i32 3, i32* %ptr <i>; yields {void}</i>
3221 %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]3222</pre>
3223</div>
3224
3225<!-- _______________________________________________________________________ -->
3226<div class="doc_subsubsection">
3227 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3228</div>
3229
3230<div class="doc_text">
3231<h5>Syntax:</h5>
3232<pre>
3233 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
3234</pre>
3235
3236<h5>Overview:</h5>
3237
3238<p>
3239The '<tt>getelementptr</tt>' instruction is used to get the address of a
3240subelement of an aggregate data structure.</p>
3241
3242<h5>Arguments:</h5>
3243
3244<p>This instruction takes a list of integer operands that indicate what
3245elements of the aggregate object to index to. The actual types of the arguments
3246provided depend on the type of the first pointer argument. The
3247'<tt>getelementptr</tt>' instruction is used to index down through the type
3248levels of a structure or to a specific index in an array. When indexing into a
3249structure, only <tt>i32</tt> integer constants are allowed. When indexing
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]3250into an array or pointer, only integers of 32 or 64 bits are allowed; 32-bit
3251values will be sign extended to 64-bits if required.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3252
3253<p>For example, let's consider a C code fragment and how it gets
3254compiled to LLVM:</p>
3255
3256<div class="doc_code">
3257<pre>
3258struct RT {
3259 char A;
3260 int B[10][20];
3261 char C;
3262};
3263struct ST {
3264 int X;
3265 double Y;
3266 struct RT Z;
3267};
3268
3269int *foo(struct ST *s) {
3270 return &amp;s[1].Z.B[5][13];
3271}
3272</pre>
3273</div>
3274
3275<p>The LLVM code generated by the GCC frontend is:</p>
3276
3277<div class="doc_code">
3278<pre>
3279%RT = type { i8 , [10 x [20 x i32]], i8 }
3280%ST = type { i32, double, %RT }
3281
3282define i32* %foo(%ST* %s) {
3283entry:
3284 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3285 ret i32* %reg
3286}
3287</pre>
3288</div>
3289
3290<h5>Semantics:</h5>
3291
3292<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
3293on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
3294and <a href="#t_array">array</a> types can use a 32-bit or 64-bit
3295<a href="#t_integer">integer</a> type but the value will always be sign extended
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3296to 64-bits. <a href="#t_struct">Structure</a> and <a href="#t_pstruct">packed
3297structure</a> types require <tt>i32</tt> <b>constants</b>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3298
3299<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
3300type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3301}</tt>' type, a structure. The second index indexes into the third element of
3302the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3303i8 }</tt>' type, another structure. The third index indexes into the second
3304element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3305array. The two dimensions of the array are subscripted into, yielding an
3306'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3307to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
3308
3309<p>Note that it is perfectly legal to index partially through a
3310structure, returning a pointer to an inner element. Because of this,
3311the LLVM code for the given testcase is equivalent to:</p>
3312
3313<pre>
3314 define i32* %foo(%ST* %s) {
3315 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3316 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3317 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3318 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3319 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3320 ret i32* %t5
3321 }
3322</pre>
3323
3324<p>Note that it is undefined to access an array out of bounds: array and
3325pointer indexes must always be within the defined bounds of the array type.
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]3326The one exception for this rule is zero length arrays. These arrays are
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3327defined to be accessible as variable length arrays, which requires access
3328beyond the zero'th element.</p>
3329
3330<p>The getelementptr instruction is often confusing. For some more insight
3331into how it works, see <a href="GetElementPtr.html">the getelementptr
3332FAQ</a>.</p>
3333
3334<h5>Example:</h5>
3335
3336<pre>
3337 <i>; yields [12 x i8]*:aptr</i>
3338 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
3339</pre>
3340</div>
3341
3342<!-- ======================================================================= -->
3343<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3344</div>
3345<div class="doc_text">
3346<p>The instructions in this category are the conversion instructions (casting)
3347which all take a single operand and a type. They perform various bit conversions
3348on the operand.</p>
3349</div>
3350
3351<!-- _______________________________________________________________________ -->
3352<div class="doc_subsubsection">
3353 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3354</div>
3355<div class="doc_text">
3356
3357<h5>Syntax:</h5>
3358<pre>
3359 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3360</pre>
3361
3362<h5>Overview:</h5>
3363<p>
3364The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3365</p>
3366
3367<h5>Arguments:</h5>
3368<p>
3369The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3370be an <a href="#t_integer">integer</a> type, and a type that specifies the size
3371and type of the result, which must be an <a href="#t_integer">integer</a>
3372type. The bit size of <tt>value</tt> must be larger than the bit size of
3373<tt>ty2</tt>. Equal sized types are not allowed.</p>
3374
3375<h5>Semantics:</h5>
3376<p>
3377The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
3378and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3379larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3380It will always truncate bits.</p>
3381
3382<h5>Example:</h5>
3383<pre>
3384 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3385 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3386 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
3387</pre>
3388</div>
3389
3390<!-- _______________________________________________________________________ -->
3391<div class="doc_subsubsection">
3392 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3393</div>
3394<div class="doc_text">
3395
3396<h5>Syntax:</h5>
3397<pre>
3398 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3399</pre>
3400
3401<h5>Overview:</h5>
3402<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3403<tt>ty2</tt>.</p>
3404
3405
3406<h5>Arguments:</h5>
3407<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
3408<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3409also be of <a href="#t_integer">integer</a> type. The bit size of the
3410<tt>value</tt> must be smaller than the bit size of the destination type,
3411<tt>ty2</tt>.</p>
3412
3413<h5>Semantics:</h5>
3414<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
3415bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
3416
3417<p>When zero extending from i1, the result will always be either 0 or 1.</p>
3418
3419<h5>Example:</h5>
3420<pre>
3421 %X = zext i32 257 to i64 <i>; yields i64:257</i>
3422 %Y = zext i1 true to i32 <i>; yields i32:1</i>
3423</pre>
3424</div>
3425
3426<!-- _______________________________________________________________________ -->
3427<div class="doc_subsubsection">
3428 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3429</div>
3430<div class="doc_text">
3431
3432<h5>Syntax:</h5>
3433<pre>
3434 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3435</pre>
3436
3437<h5>Overview:</h5>
3438<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3439
3440<h5>Arguments:</h5>
3441<p>
3442The '<tt>sext</tt>' instruction takes a value to cast, which must be of
3443<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3444also be of <a href="#t_integer">integer</a> type. The bit size of the
3445<tt>value</tt> must be smaller than the bit size of the destination type,
3446<tt>ty2</tt>.</p>
3447
3448<h5>Semantics:</h5>
3449<p>
3450The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3451bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
3452the type <tt>ty2</tt>.</p>
3453
3454<p>When sign extending from i1, the extension always results in -1 or 0.</p>
3455
3456<h5>Example:</h5>
3457<pre>
3458 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
3459 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
3460</pre>
3461</div>
3462
3463<!-- _______________________________________________________________________ -->
3464<div class="doc_subsubsection">
3465 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3466</div>
3467
3468<div class="doc_text">
3469
3470<h5>Syntax:</h5>
3471
3472<pre>
3473 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3474</pre>
3475
3476<h5>Overview:</h5>
3477<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3478<tt>ty2</tt>.</p>
3479
3480
3481<h5>Arguments:</h5>
3482<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3483 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3484cast it to. The size of <tt>value</tt> must be larger than the size of
3485<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3486<i>no-op cast</i>.</p>
3487
3488<h5>Semantics:</h5>
3489<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3490<a href="#t_floating">floating point</a> type to a smaller
3491<a href="#t_floating">floating point</a> type. If the value cannot fit within
3492the destination type, <tt>ty2</tt>, then the results are undefined.</p>
3493
3494<h5>Example:</h5>
3495<pre>
3496 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3497 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3498</pre>
3499</div>
3500
3501<!-- _______________________________________________________________________ -->
3502<div class="doc_subsubsection">
3503 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3504</div>
3505<div class="doc_text">
3506
3507<h5>Syntax:</h5>
3508<pre>
3509 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3510</pre>
3511
3512<h5>Overview:</h5>
3513<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3514floating point value.</p>
3515
3516<h5>Arguments:</h5>
3517<p>The '<tt>fpext</tt>' instruction takes a
3518<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
3519and a <a href="#t_floating">floating point</a> type to cast it to. The source
3520type must be smaller than the destination type.</p>
3521
3522<h5>Semantics:</h5>
3523<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
3524<a href="#t_floating">floating point</a> type to a larger
3525<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
3526used to make a <i>no-op cast</i> because it always changes bits. Use
3527<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
3528
3529<h5>Example:</h5>
3530<pre>
3531 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3532 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3533</pre>
3534</div>
3535
3536<!-- _______________________________________________________________________ -->
3537<div class="doc_subsubsection">
3538 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
3539</div>
3540<div class="doc_text">
3541
3542<h5>Syntax:</h5>
3543<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3544 &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]3545</pre>
3546
3547<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3548<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3549unsigned integer equivalent of type <tt>ty2</tt>.
3550</p>
3551
3552<h5>Arguments:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3553<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]3554scalar or vector <a href="#t_floating">floating point</a> value, and a type
3555to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3556type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3557vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3558
3559<h5>Semantics:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3560<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3561<a href="#t_floating">floating point</a> operand into the nearest (rounding
3562towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3563the results are undefined.</p>
3564
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3565<h5>Example:</h5>
3566<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3567 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3568 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3569 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3570</pre>
3571</div>
3572
3573<!-- _______________________________________________________________________ -->
3574<div class="doc_subsubsection">
3575 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
3576</div>
3577<div class="doc_text">
3578
3579<h5>Syntax:</h5>
3580<pre>
3581 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3582</pre>
3583
3584<h5>Overview:</h5>
3585<p>The '<tt>fptosi</tt>' instruction converts
3586<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
3587</p>
3588
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3589<h5>Arguments:</h5>
3590<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]3591scalar or vector <a href="#t_floating">floating point</a> value, and a type
3592to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3593type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3594vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3595
3596<h5>Semantics:</h5>
3597<p>The '<tt>fptosi</tt>' instruction converts its
3598<a href="#t_floating">floating point</a> operand into the nearest (rounding
3599towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3600the results are undefined.</p>
3601
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3602<h5>Example:</h5>
3603<pre>
3604 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3605 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3606 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
3607</pre>
3608</div>
3609
3610<!-- _______________________________________________________________________ -->
3611<div class="doc_subsubsection">
3612 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
3613</div>
3614<div class="doc_text">
3615
3616<h5>Syntax:</h5>
3617<pre>
3618 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3619</pre>
3620
3621<h5>Overview:</h5>
3622<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
3623integer and converts that value to the <tt>ty2</tt> type.</p>
3624
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3625<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3626<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3627scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3628to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3629type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3630floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3631
3632<h5>Semantics:</h5>
3633<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
3634integer quantity and converts it to the corresponding floating point value. If
3635the value cannot fit in the floating point value, the results are undefined.</p>
3636
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3637<h5>Example:</h5>
3638<pre>
3639 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
3640 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
3641</pre>
3642</div>
3643
3644<!-- _______________________________________________________________________ -->
3645<div class="doc_subsubsection">
3646 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
3647</div>
3648<div class="doc_text">
3649
3650<h5>Syntax:</h5>
3651<pre>
3652 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3653</pre>
3654
3655<h5>Overview:</h5>
3656<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
3657integer and converts that value to the <tt>ty2</tt> type.</p>
3658
3659<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3660<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3661scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3662to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3663type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3664floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3665
3666<h5>Semantics:</h5>
3667<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
3668integer quantity and converts it to the corresponding floating point value. If
3669the value cannot fit in the floating point value, the results are undefined.</p>
3670
3671<h5>Example:</h5>
3672<pre>
3673 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
3674 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
3675</pre>
3676</div>
3677
3678<!-- _______________________________________________________________________ -->
3679<div class="doc_subsubsection">
3680 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3681</div>
3682<div class="doc_text">
3683
3684<h5>Syntax:</h5>
3685<pre>
3686 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3687</pre>
3688
3689<h5>Overview:</h5>
3690<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3691the integer type <tt>ty2</tt>.</p>
3692
3693<h5>Arguments:</h5>
3694<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3695must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
3696<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3697
3698<h5>Semantics:</h5>
3699<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3700<tt>ty2</tt> by interpreting the pointer value as an integer and either
3701truncating or zero extending that value to the size of the integer type. If
3702<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3703<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3704are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3705change.</p>
3706
3707<h5>Example:</h5>
3708<pre>
3709 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3710 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
3711</pre>
3712</div>
3713
3714<!-- _______________________________________________________________________ -->
3715<div class="doc_subsubsection">
3716 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3717</div>
3718<div class="doc_text">
3719
3720<h5>Syntax:</h5>
3721<pre>
3722 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3723</pre>
3724
3725<h5>Overview:</h5>
3726<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3727a pointer type, <tt>ty2</tt>.</p>
3728
3729<h5>Arguments:</h5>
3730<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
3731value to cast, and a type to cast it to, which must be a
3732<a href="#t_pointer">pointer</a> type.
3733
3734<h5>Semantics:</h5>
3735<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3736<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3737the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3738size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3739the size of a pointer then a zero extension is done. If they are the same size,
3740nothing is done (<i>no-op cast</i>).</p>
3741
3742<h5>Example:</h5>
3743<pre>
3744 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3745 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3746 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
3747</pre>
3748</div>
3749
3750<!-- _______________________________________________________________________ -->
3751<div class="doc_subsubsection">
3752 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
3753</div>
3754<div class="doc_text">
3755
3756<h5>Syntax:</h5>
3757<pre>
3758 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3759</pre>
3760
3761<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3762
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3763<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
3764<tt>ty2</tt> without changing any bits.</p>
3765
3766<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3767
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3768<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
3769a first class value, and a type to cast it to, which must also be a <a
3770 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
3771and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3772type is a pointer, the destination type must also be a pointer. This
3773instruction supports bitwise conversion of vectors to integers and to vectors
3774of other types (as long as they have the same size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3775
3776<h5>Semantics:</h5>
3777<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
3778<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3779this conversion. The conversion is done as if the <tt>value</tt> had been
3780stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3781converted to other pointer types with this instruction. To convert pointers to
3782other types, use the <a href="#i_inttoptr">inttoptr</a> or
3783<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
3784
3785<h5>Example:</h5>
3786<pre>
3787 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
3788 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3789 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
3790</pre>
3791</div>
3792
3793<!-- ======================================================================= -->
3794<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3795<div class="doc_text">
3796<p>The instructions in this category are the "miscellaneous"
3797instructions, which defy better classification.</p>
3798</div>
3799
3800<!-- _______________________________________________________________________ -->
3801<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3802</div>
3803<div class="doc_text">
3804<h5>Syntax:</h5>
3805<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
3806</pre>
3807<h5>Overview:</h5>
3808<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3809of its two integer or pointer operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3810<h5>Arguments:</h5>
3811<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
3812the condition code indicating the kind of comparison to perform. It is not
3813a value, just a keyword. The possible condition code are:
3814<ol>
3815 <li><tt>eq</tt>: equal</li>
3816 <li><tt>ne</tt>: not equal </li>
3817 <li><tt>ugt</tt>: unsigned greater than</li>
3818 <li><tt>uge</tt>: unsigned greater or equal</li>
3819 <li><tt>ult</tt>: unsigned less than</li>
3820 <li><tt>ule</tt>: unsigned less or equal</li>
3821 <li><tt>sgt</tt>: signed greater than</li>
3822 <li><tt>sge</tt>: signed greater or equal</li>
3823 <li><tt>slt</tt>: signed less than</li>
3824 <li><tt>sle</tt>: signed less or equal</li>
3825</ol>
3826<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
3827<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
3828<h5>Semantics:</h5>
3829<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3830the condition code given as <tt>cond</tt>. The comparison performed always
3831yields a <a href="#t_primitive">i1</a> result, as follows:
3832<ol>
3833 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3834 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3835 </li>
3836 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3837 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3838 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3839 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3840 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3841 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3842 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3843 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3844 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3845 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3846 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3847 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3848 <li><tt>sge</tt>: interprets the operands as signed values and yields
3849 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3850 <li><tt>slt</tt>: interprets the operands as signed values and yields
3851 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3852 <li><tt>sle</tt>: interprets the operands as signed values and yields
3853 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3854</ol>
3855<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
3856values are compared as if they were integers.</p>
3857
3858<h5>Example:</h5>
3859<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3860 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3861 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3862 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3863 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3864 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
3865</pre>
3866</div>
3867
3868<!-- _______________________________________________________________________ -->
3869<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3870</div>
3871<div class="doc_text">
3872<h5>Syntax:</h5>
3873<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
3874</pre>
3875<h5>Overview:</h5>
3876<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3877of its floating point operands.</p>
3878<h5>Arguments:</h5>
3879<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
3880the condition code indicating the kind of comparison to perform. It is not
3881a value, just a keyword. The possible condition code are:
3882<ol>
3883 <li><tt>false</tt>: no comparison, always returns false</li>
3884 <li><tt>oeq</tt>: ordered and equal</li>
3885 <li><tt>ogt</tt>: ordered and greater than </li>
3886 <li><tt>oge</tt>: ordered and greater than or equal</li>
3887 <li><tt>olt</tt>: ordered and less than </li>
3888 <li><tt>ole</tt>: ordered and less than or equal</li>
3889 <li><tt>one</tt>: ordered and not equal</li>
3890 <li><tt>ord</tt>: ordered (no nans)</li>
3891 <li><tt>ueq</tt>: unordered or equal</li>
3892 <li><tt>ugt</tt>: unordered or greater than </li>
3893 <li><tt>uge</tt>: unordered or greater than or equal</li>
3894 <li><tt>ult</tt>: unordered or less than </li>
3895 <li><tt>ule</tt>: unordered or less than or equal</li>
3896 <li><tt>une</tt>: unordered or not equal</li>
3897 <li><tt>uno</tt>: unordered (either nans)</li>
3898 <li><tt>true</tt>: no comparison, always returns true</li>
3899</ol>
3900<p><i>Ordered</i> means that neither operand is a QNAN while
3901<i>unordered</i> means that either operand may be a QNAN.</p>
3902<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3903<a href="#t_floating">floating point</a> typed. They must have identical
3904types.</p>
3905<h5>Semantics:</h5>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]3906<p>The '<tt>fcmp</tt>' instruction compares <tt>var1</tt> and <tt>var2</tt>
3907according to the condition code given as <tt>cond</tt>. The comparison performed
3908always yields a <a href="#t_primitive">i1</a> result, as follows:
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3909<ol>
3910 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
3911 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
3912 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
3913 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
3914 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
3915 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
3916 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3917 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
3918 <tt>var1</tt> is less than <tt>var2</tt>.</li>
3919 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
3920 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3921 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
3922 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
3923 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3924 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
3925 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
3926 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
3927 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3928 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
3929 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3930 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
3931 <tt>var1</tt> is less than <tt>var2</tt>.</li>
3932 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
3933 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3934 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
3935 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
3936 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
3937 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3938</ol>
3939
3940<h5>Example:</h5>
3941<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3942 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3943 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3944 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3945</pre>
3946</div>
3947
3948<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]3949<div class="doc_subsubsection">
3950 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
3951</div>
3952<div class="doc_text">
3953<h5>Syntax:</h5>
3954<pre> &lt;result&gt; = vicmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
3955</pre>
3956<h5>Overview:</h5>
3957<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
3958element-wise comparison of its two integer vector operands.</p>
3959<h5>Arguments:</h5>
3960<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
3961the condition code indicating the kind of comparison to perform. It is not
3962a value, just a keyword. The possible condition code are:
3963<ol>
3964 <li><tt>eq</tt>: equal</li>
3965 <li><tt>ne</tt>: not equal </li>
3966 <li><tt>ugt</tt>: unsigned greater than</li>
3967 <li><tt>uge</tt>: unsigned greater or equal</li>
3968 <li><tt>ult</tt>: unsigned less than</li>
3969 <li><tt>ule</tt>: unsigned less or equal</li>
3970 <li><tt>sgt</tt>: signed greater than</li>
3971 <li><tt>sge</tt>: signed greater or equal</li>
3972 <li><tt>slt</tt>: signed less than</li>
3973 <li><tt>sle</tt>: signed less or equal</li>
3974</ol>
3975<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
3976<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
3977<h5>Semantics:</h5>
3978<p>The '<tt>vicmp</tt>' instruction compares <tt>var1</tt> and <tt>var2</tt>
3979according to the condition code given as <tt>cond</tt>. The comparison yields a
3980<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
3981identical type as the values being compared. The most significant bit in each
3982element is 1 if the element-wise comparison evaluates to true, and is 0
3983otherwise. All other bits of the result are undefined. The condition codes
3984are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
3985instruction</a>.
3986
3987<h5>Example:</h5>
3988<pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3989 &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>
3990 &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]3991</pre>
3992</div>
3993
3994<!-- _______________________________________________________________________ -->
3995<div class="doc_subsubsection">
3996 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
3997</div>
3998<div class="doc_text">
3999<h5>Syntax:</h5>
4000<pre> &lt;result&gt; = vfcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt;</pre>
4001<h5>Overview:</h5>
4002<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
4003element-wise comparison of its two floating point vector operands. The output
4004elements have the same width as the input elements.</p>
4005<h5>Arguments:</h5>
4006<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
4007the condition code indicating the kind of comparison to perform. It is not
4008a value, just a keyword. The possible condition code are:
4009<ol>
4010 <li><tt>false</tt>: no comparison, always returns false</li>
4011 <li><tt>oeq</tt>: ordered and equal</li>
4012 <li><tt>ogt</tt>: ordered and greater than </li>
4013 <li><tt>oge</tt>: ordered and greater than or equal</li>
4014 <li><tt>olt</tt>: ordered and less than </li>
4015 <li><tt>ole</tt>: ordered and less than or equal</li>
4016 <li><tt>one</tt>: ordered and not equal</li>
4017 <li><tt>ord</tt>: ordered (no nans)</li>
4018 <li><tt>ueq</tt>: unordered or equal</li>
4019 <li><tt>ugt</tt>: unordered or greater than </li>
4020 <li><tt>uge</tt>: unordered or greater than or equal</li>
4021 <li><tt>ult</tt>: unordered or less than </li>
4022 <li><tt>ule</tt>: unordered or less than or equal</li>
4023 <li><tt>une</tt>: unordered or not equal</li>
4024 <li><tt>uno</tt>: unordered (either nans)</li>
4025 <li><tt>true</tt>: no comparison, always returns true</li>
4026</ol>
4027<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4028<a href="#t_floating">floating point</a> typed. They must also be identical
4029types.</p>
4030<h5>Semantics:</h5>
4031<p>The '<tt>vfcmp</tt>' instruction compares <tt>var1</tt> and <tt>var2</tt>
4032according to the condition code given as <tt>cond</tt>. The comparison yields a
4033<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4034an identical number of elements as the values being compared, and each element
4035having identical with to the width of the floating point elements. The most
4036significant bit in each element is 1 if the element-wise comparison evaluates to
4037true, and is 0 otherwise. All other bits of the result are undefined. The
4038condition codes are evaluated identically to the
4039<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.
4040
4041<h5>Example:</h5>
4042<pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4043 &lt;result&gt; = vfcmp oeq &lt;2 x float&gt; &lt; float 4, float 0 &gt;, &lt; float 5, float 0 &gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4044 &lt;result&gt; = vfcmp ult &lt;2 x double&gt; &lt; double 1, double 2 &gt;, &lt; double 2, double 2&gt; <i>; yields: result=&lt;2 x i64&gt; &lt; i64 -1, i64 0 &gt;</i>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4045</pre>
4046</div>
4047
4048<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4049<div class="doc_subsubsection">
4050 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4051</div>
4052
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4053<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4054
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4055<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4056
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4057<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4058<h5>Overview:</h5>
4059<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4060the SSA graph representing the function.</p>
4061<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4062
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4063<p>The type of the incoming values is specified with the first type
4064field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4065as arguments, with one pair for each predecessor basic block of the
4066current block. Only values of <a href="#t_firstclass">first class</a>
4067type may be used as the value arguments to the PHI node. Only labels
4068may be used as the label arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4069
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4070<p>There must be no non-phi instructions between the start of a basic
4071block and the PHI instructions: i.e. PHI instructions must be first in
4072a basic block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4073
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4074<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4075
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4076<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4077specified by the pair corresponding to the predecessor basic block that executed
4078just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4079
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4080<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4081<pre>
4082Loop: ; Infinite loop that counts from 0 on up...
4083 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4084 %nextindvar = add i32 %indvar, 1
4085 br label %Loop
4086</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4087</div>
4088
4089<!-- _______________________________________________________________________ -->
4090<div class="doc_subsubsection">
4091 <a name="i_select">'<tt>select</tt>' Instruction</a>
4092</div>
4093
4094<div class="doc_text">
4095
4096<h5>Syntax:</h5>
4097
4098<pre>
4099 &lt;result&gt; = select i1 &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
4100</pre>
4101
4102<h5>Overview:</h5>
4103
4104<p>
4105The '<tt>select</tt>' instruction is used to choose one value based on a
4106condition, without branching.
4107</p>
4108
4109
4110<h5>Arguments:</h5>
4111
4112<p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4113The '<tt>select</tt>' instruction requires an 'i1' value indicating the
4114condition, and two values of the same <a href="#t_firstclass">first class</a>
4115type. If the val1/val2 are vectors, the entire vectors are selected, not
4116individual elements.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4117</p>
4118
4119<h5>Semantics:</h5>
4120
4121<p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4122If the i1 condition evaluates is 1, the instruction returns the first
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4123value argument; otherwise, it returns the second value argument.
4124</p>
4125
4126<h5>Example:</h5>
4127
4128<pre>
4129 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4130</pre>
4131</div>
4132
4133
4134<!-- _______________________________________________________________________ -->
4135<div class="doc_subsubsection">
4136 <a name="i_call">'<tt>call</tt>' Instruction</a>
4137</div>
4138
4139<div class="doc_text">
4140
4141<h5>Syntax:</h5>
4142<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4143 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] &lt;ty&gt; [&lt;fnty&gt;*] &lt;fnptrval&gt;(&lt;param list&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4144</pre>
4145
4146<h5>Overview:</h5>
4147
4148<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4149
4150<h5>Arguments:</h5>
4151
4152<p>This instruction requires several arguments:</p>
4153
4154<ol>
4155 <li>
4156 <p>The optional "tail" marker indicates whether the callee function accesses
4157 any allocas or varargs in the caller. If the "tail" marker is present, the
4158 function call is eligible for tail call optimization. Note that calls may
4159 be marked "tail" even if they do not occur before a <a
4160 href="#i_ret"><tt>ret</tt></a> instruction.
4161 </li>
4162 <li>
4163 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
4164 convention</a> the call should use. If none is specified, the call defaults
4165 to using C calling conventions.
4166 </li>
4167 <li>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4168 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4169 the type of the return value. Functions that return no value are marked
4170 <tt><a href="#t_void">void</a></tt>.</p>
4171 </li>
4172 <li>
4173 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4174 value being invoked. The argument types must match the types implied by
4175 this signature. This type can be omitted if the function is not varargs
4176 and if the function type does not return a pointer to a function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4177 </li>
4178 <li>
4179 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4180 be invoked. In most cases, this is a direct function invocation, but
4181 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4182 to function value.</p>
4183 </li>
4184 <li>
4185 <p>'<tt>function args</tt>': argument list whose types match the
4186 function signature argument types. All arguments must be of
4187 <a href="#t_firstclass">first class</a> type. If the function signature
4188 indicates the function accepts a variable number of arguments, the extra
4189 arguments can be specified.</p>
4190 </li>
4191</ol>
4192
4193<h5>Semantics:</h5>
4194
4195<p>The '<tt>call</tt>' instruction is used to cause control flow to
4196transfer to a specified function, with its incoming arguments bound to
4197the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4198instruction in the called function, control flow continues with the
4199instruction after the function call, and the return value of the
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4200function is bound to the result argument. If the callee returns multiple
4201values then the return values of the function are only accessible through
4202the '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4203
4204<h5>Example:</h5>
4205
4206<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4207 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4208 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4209 %X = tail call i32 @foo() <i>; yields i32</i>
4210 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4211 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4212
4213 %struct.A = type { i32, i8 }
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4214 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
4215 %gr = getresult %struct.A %r, 0 <i>; yields i32</i>
4216 %gr1 = getresult %struct.A %r, 1 <i>; yields i8</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4217</pre>
4218
4219</div>
4220
4221<!-- _______________________________________________________________________ -->
4222<div class="doc_subsubsection">
4223 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4224</div>
4225
4226<div class="doc_text">
4227
4228<h5>Syntax:</h5>
4229
4230<pre>
4231 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4232</pre>
4233
4234<h5>Overview:</h5>
4235
4236<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
4237the "variable argument" area of a function call. It is used to implement the
4238<tt>va_arg</tt> macro in C.</p>
4239
4240<h5>Arguments:</h5>
4241
4242<p>This instruction takes a <tt>va_list*</tt> value and the type of
4243the argument. It returns a value of the specified argument type and
4244increments the <tt>va_list</tt> to point to the next argument. The
4245actual type of <tt>va_list</tt> is target specific.</p>
4246
4247<h5>Semantics:</h5>
4248
4249<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4250type from the specified <tt>va_list</tt> and causes the
4251<tt>va_list</tt> to point to the next argument. For more information,
4252see the variable argument handling <a href="#int_varargs">Intrinsic
4253Functions</a>.</p>
4254
4255<p>It is legal for this instruction to be called in a function which does not
4256take a variable number of arguments, for example, the <tt>vfprintf</tt>
4257function.</p>
4258
4259<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
4260href="#intrinsics">intrinsic function</a> because it takes a type as an
4261argument.</p>
4262
4263<h5>Example:</h5>
4264
4265<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4266
4267</div>
4268
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4269<!-- _______________________________________________________________________ -->
4270<div class="doc_subsubsection">
4271 <a name="i_getresult">'<tt>getresult</tt>' Instruction</a>
4272</div>
4273
4274<div class="doc_text">
4275
4276<h5>Syntax:</h5>
4277<pre>
Chris Lattneree9da3f2008-03-21 17:20:51 +0000[diff] [blame]4278 &lt;resultval&gt; = getresult &lt;type&gt; &lt;retval&gt;, &lt;index&gt;
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4279</pre>
Chris Lattneree9da3f2008-03-21 17:20:51 +0000[diff] [blame]4280
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4281<h5>Overview:</h5>
4282
4283<p> The '<tt>getresult</tt>' instruction is used to extract individual values
Chris Lattneree9da3f2008-03-21 17:20:51 +0000[diff] [blame]4284from a '<tt><a href="#i_call">call</a></tt>'
4285or '<tt><a href="#i_invoke">invoke</a></tt>' instruction that returns multiple
4286results.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4287
4288<h5>Arguments:</h5>
4289
Chris Lattneree9da3f2008-03-21 17:20:51 +0000[diff] [blame]4290<p>The '<tt>getresult</tt>' instruction takes a call or invoke value as its
Chris Lattnerd8dd3522008-04-23 04:06:52 +0000[diff] [blame]4291first argument, or an undef value. The value must have <a
4292href="#t_struct">structure type</a>. The second argument is a constant
4293unsigned index value which must be in range for the number of values returned
4294by the call.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4295
4296<h5>Semantics:</h5>
4297
Chris Lattneree9da3f2008-03-21 17:20:51 +0000[diff] [blame]4298<p>The '<tt>getresult</tt>' instruction extracts the element identified by
4299'<tt>index</tt>' from the aggregate value.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4300
4301<h5>Example:</h5>
4302
4303<pre>
4304 %struct.A = type { i32, i8 }
4305
4306 %r = call %struct.A @foo()
Chris Lattneree9da3f2008-03-21 17:20:51 +0000[diff] [blame]4307 %gr = getresult %struct.A %r, 0 <i>; yields i32:%gr</i>
4308 %gr1 = getresult %struct.A %r, 1 <i>; yields i8:%gr1</i>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4309 add i32 %gr, 42
4310 add i8 %gr1, 41
4311</pre>
4312
4313</div>
4314
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4315<!-- *********************************************************************** -->
4316<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4317<!-- *********************************************************************** -->
4318
4319<div class="doc_text">
4320
4321<p>LLVM supports the notion of an "intrinsic function". These functions have
4322well known names and semantics and are required to follow certain restrictions.
4323Overall, these intrinsics represent an extension mechanism for the LLVM
4324language that does not require changing all of the transformations in LLVM when
4325adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
4326
4327<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
4328prefix is reserved in LLVM for intrinsic names; thus, function names may not
4329begin with this prefix. Intrinsic functions must always be external functions:
4330you cannot define the body of intrinsic functions. Intrinsic functions may
4331only be used in call or invoke instructions: it is illegal to take the address
4332of an intrinsic function. Additionally, because intrinsic functions are part
4333of the LLVM language, it is required if any are added that they be documented
4334here.</p>
4335
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4336<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4337a family of functions that perform the same operation but on different data
4338types. Because LLVM can represent over 8 million different integer types,
4339overloading is used commonly to allow an intrinsic function to operate on any
4340integer type. One or more of the argument types or the result type can be
4341overloaded to accept any integer type. Argument types may also be defined as
4342exactly matching a previous argument's type or the result type. This allows an
4343intrinsic function which accepts multiple arguments, but needs all of them to
4344be of the same type, to only be overloaded with respect to a single argument or
4345the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4346
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4347<p>Overloaded intrinsics will have the names of its overloaded argument types
4348encoded into its function name, each preceded by a period. Only those types
4349which are overloaded result in a name suffix. Arguments whose type is matched
4350against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4351take an integer of any width and returns an integer of exactly the same integer
4352width. This leads to a family of functions such as
4353<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4354Only one type, the return type, is overloaded, and only one type suffix is
4355required. Because the argument's type is matched against the return type, it
4356does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4357
4358<p>To learn how to add an intrinsic function, please see the
4359<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
4360</p>
4361
4362</div>
4363
4364<!-- ======================================================================= -->
4365<div class="doc_subsection">
4366 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4367</div>
4368
4369<div class="doc_text">
4370
4371<p>Variable argument support is defined in LLVM with the <a
4372 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4373intrinsic functions. These functions are related to the similarly
4374named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
4375
4376<p>All of these functions operate on arguments that use a
4377target-specific value type "<tt>va_list</tt>". The LLVM assembly
4378language reference manual does not define what this type is, so all
4379transformations should be prepared to handle these functions regardless of
4380the type used.</p>
4381
4382<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
4383instruction and the variable argument handling intrinsic functions are
4384used.</p>
4385
4386<div class="doc_code">
4387<pre>
4388define i32 @test(i32 %X, ...) {
4389 ; Initialize variable argument processing
4390 %ap = alloca i8*
4391 %ap2 = bitcast i8** %ap to i8*
4392 call void @llvm.va_start(i8* %ap2)
4393
4394 ; Read a single integer argument
4395 %tmp = va_arg i8** %ap, i32
4396
4397 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4398 %aq = alloca i8*
4399 %aq2 = bitcast i8** %aq to i8*
4400 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4401 call void @llvm.va_end(i8* %aq2)
4402
4403 ; Stop processing of arguments.
4404 call void @llvm.va_end(i8* %ap2)
4405 ret i32 %tmp
4406}
4407
4408declare void @llvm.va_start(i8*)
4409declare void @llvm.va_copy(i8*, i8*)
4410declare void @llvm.va_end(i8*)
4411</pre>
4412</div>
4413
4414</div>
4415
4416<!-- _______________________________________________________________________ -->
4417<div class="doc_subsubsection">
4418 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4419</div>
4420
4421
4422<div class="doc_text">
4423<h5>Syntax:</h5>
4424<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
4425<h5>Overview:</h5>
4426<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
4427<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4428href="#i_va_arg">va_arg</a></tt>.</p>
4429
4430<h5>Arguments:</h5>
4431
4432<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
4433
4434<h5>Semantics:</h5>
4435
4436<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
4437macro available in C. In a target-dependent way, it initializes the
4438<tt>va_list</tt> element to which the argument points, so that the next call to
4439<tt>va_arg</tt> will produce the first variable argument passed to the function.
4440Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
4441last argument of the function as the compiler can figure that out.</p>
4442
4443</div>
4444
4445<!-- _______________________________________________________________________ -->
4446<div class="doc_subsubsection">
4447 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
4448</div>
4449
4450<div class="doc_text">
4451<h5>Syntax:</h5>
4452<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
4453<h5>Overview:</h5>
4454
4455<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
4456which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
4457or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
4458
4459<h5>Arguments:</h5>
4460
4461<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
4462
4463<h5>Semantics:</h5>
4464
4465<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
4466macro available in C. In a target-dependent way, it destroys the
4467<tt>va_list</tt> element to which the argument points. Calls to <a
4468href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4469<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4470<tt>llvm.va_end</tt>.</p>
4471
4472</div>
4473
4474<!-- _______________________________________________________________________ -->
4475<div class="doc_subsubsection">
4476 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
4477</div>
4478
4479<div class="doc_text">
4480
4481<h5>Syntax:</h5>
4482
4483<pre>
4484 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
4485</pre>
4486
4487<h5>Overview:</h5>
4488
4489<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4490from the source argument list to the destination argument list.</p>
4491
4492<h5>Arguments:</h5>
4493
4494<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
4495The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
4496
4497
4498<h5>Semantics:</h5>
4499
4500<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4501macro available in C. In a target-dependent way, it copies the source
4502<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4503intrinsic is necessary because the <tt><a href="#int_va_start">
4504llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4505example, memory allocation.</p>
4506
4507</div>
4508
4509<!-- ======================================================================= -->
4510<div class="doc_subsection">
4511 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4512</div>
4513
4514<div class="doc_text">
4515
4516<p>
4517LLVM support for <a href="GarbageCollection.html">Accurate Garbage
4518Collection</a> requires the implementation and generation of these intrinsics.
4519These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
4520stack</a>, as well as garbage collector implementations that require <a
4521href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
4522Front-ends for type-safe garbage collected languages should generate these
4523intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4524href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4525</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]4526
4527<p>The garbage collection intrinsics only operate on objects in the generic
4528 address space (address space zero).</p>
4529
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4530</div>
4531
4532<!-- _______________________________________________________________________ -->
4533<div class="doc_subsubsection">
4534 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
4535</div>
4536
4537<div class="doc_text">
4538
4539<h5>Syntax:</h5>
4540
4541<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4542 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4543</pre>
4544
4545<h5>Overview:</h5>
4546
4547<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
4548the code generator, and allows some metadata to be associated with it.</p>
4549
4550<h5>Arguments:</h5>
4551
4552<p>The first argument specifies the address of a stack object that contains the
4553root pointer. The second pointer (which must be either a constant or a global
4554value address) contains the meta-data to be associated with the root.</p>
4555
4556<h5>Semantics:</h5>
4557
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]4558<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]4559location. At compile-time, the code generator generates information to allow
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4560the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4561intrinsic may only be used in a function which <a href="#gc">specifies a GC
4562algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4563
4564</div>
4565
4566
4567<!-- _______________________________________________________________________ -->
4568<div class="doc_subsubsection">
4569 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
4570</div>
4571
4572<div class="doc_text">
4573
4574<h5>Syntax:</h5>
4575
4576<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4577 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4578</pre>
4579
4580<h5>Overview:</h5>
4581
4582<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4583locations, allowing garbage collector implementations that require read
4584barriers.</p>
4585
4586<h5>Arguments:</h5>
4587
4588<p>The second argument is the address to read from, which should be an address
4589allocated from the garbage collector. The first object is a pointer to the
4590start of the referenced object, if needed by the language runtime (otherwise
4591null).</p>
4592
4593<h5>Semantics:</h5>
4594
4595<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4596instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4597garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4598may only be used in a function which <a href="#gc">specifies a GC
4599algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4600
4601</div>
4602
4603
4604<!-- _______________________________________________________________________ -->
4605<div class="doc_subsubsection">
4606 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
4607</div>
4608
4609<div class="doc_text">
4610
4611<h5>Syntax:</h5>
4612
4613<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4614 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4615</pre>
4616
4617<h5>Overview:</h5>
4618
4619<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4620locations, allowing garbage collector implementations that require write
4621barriers (such as generational or reference counting collectors).</p>
4622
4623<h5>Arguments:</h5>
4624
4625<p>The first argument is the reference to store, the second is the start of the
4626object to store it to, and the third is the address of the field of Obj to
4627store to. If the runtime does not require a pointer to the object, Obj may be
4628null.</p>
4629
4630<h5>Semantics:</h5>
4631
4632<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4633instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4634garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4635may only be used in a function which <a href="#gc">specifies a GC
4636algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4637
4638</div>
4639
4640
4641
4642<!-- ======================================================================= -->
4643<div class="doc_subsection">
4644 <a name="int_codegen">Code Generator Intrinsics</a>
4645</div>
4646
4647<div class="doc_text">
4648<p>
4649These intrinsics are provided by LLVM to expose special features that may only
4650be implemented with code generator support.
4651</p>
4652
4653</div>
4654
4655<!-- _______________________________________________________________________ -->
4656<div class="doc_subsubsection">
4657 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
4658</div>
4659
4660<div class="doc_text">
4661
4662<h5>Syntax:</h5>
4663<pre>
4664 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
4665</pre>
4666
4667<h5>Overview:</h5>
4668
4669<p>
4670The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4671target-specific value indicating the return address of the current function
4672or one of its callers.
4673</p>
4674
4675<h5>Arguments:</h5>
4676
4677<p>
4678The argument to this intrinsic indicates which function to return the address
4679for. Zero indicates the calling function, one indicates its caller, etc. The
4680argument is <b>required</b> to be a constant integer value.
4681</p>
4682
4683<h5>Semantics:</h5>
4684
4685<p>
4686The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4687the return address of the specified call frame, or zero if it cannot be
4688identified. The value returned by this intrinsic is likely to be incorrect or 0
4689for arguments other than zero, so it should only be used for debugging purposes.
4690</p>
4691
4692<p>
4693Note that calling this intrinsic does not prevent function inlining or other
4694aggressive transformations, so the value returned may not be that of the obvious
4695source-language caller.
4696</p>
4697</div>
4698
4699
4700<!-- _______________________________________________________________________ -->
4701<div class="doc_subsubsection">
4702 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
4703</div>
4704
4705<div class="doc_text">
4706
4707<h5>Syntax:</h5>
4708<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4709 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4710</pre>
4711
4712<h5>Overview:</h5>
4713
4714<p>
4715The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4716target-specific frame pointer value for the specified stack frame.
4717</p>
4718
4719<h5>Arguments:</h5>
4720
4721<p>
4722The argument to this intrinsic indicates which function to return the frame
4723pointer for. Zero indicates the calling function, one indicates its caller,
4724etc. The argument is <b>required</b> to be a constant integer value.
4725</p>
4726
4727<h5>Semantics:</h5>
4728
4729<p>
4730The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4731the frame address of the specified call frame, or zero if it cannot be
4732identified. The value returned by this intrinsic is likely to be incorrect or 0
4733for arguments other than zero, so it should only be used for debugging purposes.
4734</p>
4735
4736<p>
4737Note that calling this intrinsic does not prevent function inlining or other
4738aggressive transformations, so the value returned may not be that of the obvious
4739source-language caller.
4740</p>
4741</div>
4742
4743<!-- _______________________________________________________________________ -->
4744<div class="doc_subsubsection">
4745 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
4746</div>
4747
4748<div class="doc_text">
4749
4750<h5>Syntax:</h5>
4751<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4752 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4753</pre>
4754
4755<h5>Overview:</h5>
4756
4757<p>
4758The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
4759the function stack, for use with <a href="#int_stackrestore">
4760<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4761features like scoped automatic variable sized arrays in C99.
4762</p>
4763
4764<h5>Semantics:</h5>
4765
4766<p>
4767This intrinsic returns a opaque pointer value that can be passed to <a
4768href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
4769<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4770<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4771state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4772practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4773that were allocated after the <tt>llvm.stacksave</tt> was executed.
4774</p>
4775
4776</div>
4777
4778<!-- _______________________________________________________________________ -->
4779<div class="doc_subsubsection">
4780 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
4781</div>
4782
4783<div class="doc_text">
4784
4785<h5>Syntax:</h5>
4786<pre>
4787 declare void @llvm.stackrestore(i8 * %ptr)
4788</pre>
4789
4790<h5>Overview:</h5>
4791
4792<p>
4793The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4794the function stack to the state it was in when the corresponding <a
4795href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
4796useful for implementing language features like scoped automatic variable sized
4797arrays in C99.
4798</p>
4799
4800<h5>Semantics:</h5>
4801
4802<p>
4803See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
4804</p>
4805
4806</div>
4807
4808
4809<!-- _______________________________________________________________________ -->
4810<div class="doc_subsubsection">
4811 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
4812</div>
4813
4814<div class="doc_text">
4815
4816<h5>Syntax:</h5>
4817<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4818 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]4819</pre>
4820
4821<h5>Overview:</h5>
4822
4823
4824<p>
4825The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
4826a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4827no
4828effect on the behavior of the program but can change its performance
4829characteristics.
4830</p>
4831
4832<h5>Arguments:</h5>
4833
4834<p>
4835<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4836determining if the fetch should be for a read (0) or write (1), and
4837<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
4838locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
4839<tt>locality</tt> arguments must be constant integers.
4840</p>
4841
4842<h5>Semantics:</h5>
4843
4844<p>
4845This intrinsic does not modify the behavior of the program. In particular,
4846prefetches cannot trap and do not produce a value. On targets that support this
4847intrinsic, the prefetch can provide hints to the processor cache for better
4848performance.
4849</p>
4850
4851</div>
4852
4853<!-- _______________________________________________________________________ -->
4854<div class="doc_subsubsection">
4855 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
4856</div>
4857
4858<div class="doc_text">
4859
4860<h5>Syntax:</h5>
4861<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4862 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4863</pre>
4864
4865<h5>Overview:</h5>
4866
4867
4868<p>
4869The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4870(PC) in a region of
4871code to simulators and other tools. The method is target specific, but it is
4872expected that the marker will use exported symbols to transmit the PC of the marker.
4873The marker makes no guarantees that it will remain with any specific instruction
4874after optimizations. It is possible that the presence of a marker will inhibit
4875optimizations. The intended use is to be inserted after optimizations to allow
4876correlations of simulation runs.
4877</p>
4878
4879<h5>Arguments:</h5>
4880
4881<p>
4882<tt>id</tt> is a numerical id identifying the marker.
4883</p>
4884
4885<h5>Semantics:</h5>
4886
4887<p>
4888This intrinsic does not modify the behavior of the program. Backends that do not
4889support this intrinisic may ignore it.
4890</p>
4891
4892</div>
4893
4894<!-- _______________________________________________________________________ -->
4895<div class="doc_subsubsection">
4896 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
4897</div>
4898
4899<div class="doc_text">
4900
4901<h5>Syntax:</h5>
4902<pre>
4903 declare i64 @llvm.readcyclecounter( )
4904</pre>
4905
4906<h5>Overview:</h5>
4907
4908
4909<p>
4910The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4911counter register (or similar low latency, high accuracy clocks) on those targets
4912that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4913As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4914should only be used for small timings.
4915</p>
4916
4917<h5>Semantics:</h5>
4918
4919<p>
4920When directly supported, reading the cycle counter should not modify any memory.
4921Implementations are allowed to either return a application specific value or a
4922system wide value. On backends without support, this is lowered to a constant 0.
4923</p>
4924
4925</div>
4926
4927<!-- ======================================================================= -->
4928<div class="doc_subsection">
4929 <a name="int_libc">Standard C Library Intrinsics</a>
4930</div>
4931
4932<div class="doc_text">
4933<p>
4934LLVM provides intrinsics for a few important standard C library functions.
4935These intrinsics allow source-language front-ends to pass information about the
4936alignment of the pointer arguments to the code generator, providing opportunity
4937for more efficient code generation.
4938</p>
4939
4940</div>
4941
4942<!-- _______________________________________________________________________ -->
4943<div class="doc_subsubsection">
4944 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
4945</div>
4946
4947<div class="doc_text">
4948
4949<h5>Syntax:</h5>
4950<pre>
4951 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4952 i32 &lt;len&gt;, i32 &lt;align&gt;)
4953 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4954 i64 &lt;len&gt;, i32 &lt;align&gt;)
4955</pre>
4956
4957<h5>Overview:</h5>
4958
4959<p>
4960The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
4961location to the destination location.
4962</p>
4963
4964<p>
4965Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4966intrinsics do not return a value, and takes an extra alignment argument.
4967</p>
4968
4969<h5>Arguments:</h5>
4970
4971<p>
4972The first argument is a pointer to the destination, the second is a pointer to
4973the source. The third argument is an integer argument
4974specifying the number of bytes to copy, and the fourth argument is the alignment
4975of the source and destination locations.
4976</p>
4977
4978<p>
4979If the call to this intrinisic has an alignment value that is not 0 or 1, then
4980the caller guarantees that both the source and destination pointers are aligned
4981to that boundary.
4982</p>
4983
4984<h5>Semantics:</h5>
4985
4986<p>
4987The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
4988location to the destination location, which are not allowed to overlap. It
4989copies "len" bytes of memory over. If the argument is known to be aligned to
4990some boundary, this can be specified as the fourth argument, otherwise it should
4991be set to 0 or 1.
4992</p>
4993</div>
4994
4995
4996<!-- _______________________________________________________________________ -->
4997<div class="doc_subsubsection">
4998 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
4999</div>
5000
5001<div class="doc_text">
5002
5003<h5>Syntax:</h5>
5004<pre>
5005 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5006 i32 &lt;len&gt;, i32 &lt;align&gt;)
5007 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5008 i64 &lt;len&gt;, i32 &lt;align&gt;)
5009</pre>
5010
5011<h5>Overview:</h5>
5012
5013<p>
5014The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5015location to the destination location. It is similar to the
Chris Lattnerdba16ea2008-01-06 19:51:52 +0000[diff] [blame]5016'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5017</p>
5018
5019<p>
5020Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5021intrinsics do not return a value, and takes an extra alignment argument.
5022</p>
5023
5024<h5>Arguments:</h5>
5025
5026<p>
5027The first argument is a pointer to the destination, the second is a pointer to
5028the source. The third argument is an integer argument
5029specifying the number of bytes to copy, and the fourth argument is the alignment
5030of the source and destination locations.
5031</p>
5032
5033<p>
5034If the call to this intrinisic has an alignment value that is not 0 or 1, then
5035the caller guarantees that the source and destination pointers are aligned to
5036that boundary.
5037</p>
5038
5039<h5>Semantics:</h5>
5040
5041<p>
5042The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
5043location to the destination location, which may overlap. It
5044copies "len" bytes of memory over. If the argument is known to be aligned to
5045some boundary, this can be specified as the fourth argument, otherwise it should
5046be set to 0 or 1.
5047</p>
5048</div>
5049
5050
5051<!-- _______________________________________________________________________ -->
5052<div class="doc_subsubsection">
5053 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5054</div>
5055
5056<div class="doc_text">
5057
5058<h5>Syntax:</h5>
5059<pre>
5060 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5061 i32 &lt;len&gt;, i32 &lt;align&gt;)
5062 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5063 i64 &lt;len&gt;, i32 &lt;align&gt;)
5064</pre>
5065
5066<h5>Overview:</h5>
5067
5068<p>
5069The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
5070byte value.
5071</p>
5072
5073<p>
5074Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5075does 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 to fill, the second is the
5082byte value to fill it with, the third argument is an integer
5083argument specifying the number of bytes to fill, and the fourth argument is the
5084known alignment of destination location.
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 the destination pointer is aligned to that boundary.
5090</p>
5091
5092<h5>Semantics:</h5>
5093
5094<p>
5095The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5096the
5097destination location. If the argument is known to be aligned to some boundary,
5098this can be specified as the fourth argument, otherwise it should be set to 0 or
50991.
5100</p>
5101</div>
5102
5103
5104<!-- _______________________________________________________________________ -->
5105<div class="doc_subsubsection">
5106 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5107</div>
5108
5109<div class="doc_text">
5110
5111<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5112<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]5113floating point or vector of floating point type. Not all targets support all
5114types however.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5115<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5116 declare float @llvm.sqrt.f32(float %Val)
5117 declare double @llvm.sqrt.f64(double %Val)
5118 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5119 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5120 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5121</pre>
5122
5123<h5>Overview:</h5>
5124
5125<p>
5126The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5127returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5128<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattnerf914a002008-01-29 07:00:44 +0000[diff] [blame]5129negative numbers other than -0.0 (which allows for better optimization, because
5130there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5131defined to return -0.0 like IEEE sqrt.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5132</p>
5133
5134<h5>Arguments:</h5>
5135
5136<p>
5137The argument and return value are floating point numbers of the same type.
5138</p>
5139
5140<h5>Semantics:</h5>
5141
5142<p>
5143This function returns the sqrt of the specified operand if it is a nonnegative
5144floating point number.
5145</p>
5146</div>
5147
5148<!-- _______________________________________________________________________ -->
5149<div class="doc_subsubsection">
5150 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5151</div>
5152
5153<div class="doc_text">
5154
5155<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5156<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]5157floating point or vector of floating point type. Not all targets support all
5158types however.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5159<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5160 declare float @llvm.powi.f32(float %Val, i32 %power)
5161 declare double @llvm.powi.f64(double %Val, i32 %power)
5162 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5163 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5164 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5165</pre>
5166
5167<h5>Overview:</h5>
5168
5169<p>
5170The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5171specified (positive or negative) power. The order of evaluation of
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5172multiplications is not defined. When a vector of floating point type is
5173used, the second argument remains a scalar integer value.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5174</p>
5175
5176<h5>Arguments:</h5>
5177
5178<p>
5179The second argument is an integer power, and the first is a value to raise to
5180that power.
5181</p>
5182
5183<h5>Semantics:</h5>
5184
5185<p>
5186This function returns the first value raised to the second power with an
5187unspecified sequence of rounding operations.</p>
5188</div>
5189
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5190<!-- _______________________________________________________________________ -->
5191<div class="doc_subsubsection">
5192 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5193</div>
5194
5195<div class="doc_text">
5196
5197<h5>Syntax:</h5>
5198<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5199floating point or vector of floating point type. Not all targets support all
5200types however.
5201<pre>
5202 declare float @llvm.sin.f32(float %Val)
5203 declare double @llvm.sin.f64(double %Val)
5204 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5205 declare fp128 @llvm.sin.f128(fp128 %Val)
5206 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5207</pre>
5208
5209<h5>Overview:</h5>
5210
5211<p>
5212The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5213</p>
5214
5215<h5>Arguments:</h5>
5216
5217<p>
5218The argument and return value are floating point numbers of the same type.
5219</p>
5220
5221<h5>Semantics:</h5>
5222
5223<p>
5224This function returns the sine of the specified operand, returning the
5225same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5226conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5227</div>
5228
5229<!-- _______________________________________________________________________ -->
5230<div class="doc_subsubsection">
5231 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5232</div>
5233
5234<div class="doc_text">
5235
5236<h5>Syntax:</h5>
5237<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5238floating point or vector of floating point type. Not all targets support all
5239types however.
5240<pre>
5241 declare float @llvm.cos.f32(float %Val)
5242 declare double @llvm.cos.f64(double %Val)
5243 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5244 declare fp128 @llvm.cos.f128(fp128 %Val)
5245 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5246</pre>
5247
5248<h5>Overview:</h5>
5249
5250<p>
5251The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5252</p>
5253
5254<h5>Arguments:</h5>
5255
5256<p>
5257The argument and return value are floating point numbers of the same type.
5258</p>
5259
5260<h5>Semantics:</h5>
5261
5262<p>
5263This function returns the cosine of the specified operand, returning the
5264same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5265conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5266</div>
5267
5268<!-- _______________________________________________________________________ -->
5269<div class="doc_subsubsection">
5270 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5271</div>
5272
5273<div class="doc_text">
5274
5275<h5>Syntax:</h5>
5276<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5277floating point or vector of floating point type. Not all targets support all
5278types however.
5279<pre>
5280 declare float @llvm.pow.f32(float %Val, float %Power)
5281 declare double @llvm.pow.f64(double %Val, double %Power)
5282 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5283 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5284 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5285</pre>
5286
5287<h5>Overview:</h5>
5288
5289<p>
5290The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5291specified (positive or negative) power.
5292</p>
5293
5294<h5>Arguments:</h5>
5295
5296<p>
5297The second argument is a floating point power, and the first is a value to
5298raise to that power.
5299</p>
5300
5301<h5>Semantics:</h5>
5302
5303<p>
5304This function returns the first value raised to the second power,
5305returning the
5306same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5307conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5308</div>
5309
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5310
5311<!-- ======================================================================= -->
5312<div class="doc_subsection">
5313 <a name="int_manip">Bit Manipulation Intrinsics</a>
5314</div>
5315
5316<div class="doc_text">
5317<p>
5318LLVM provides intrinsics for a few important bit manipulation operations.
5319These allow efficient code generation for some algorithms.
5320</p>
5321
5322</div>
5323
5324<!-- _______________________________________________________________________ -->
5325<div class="doc_subsubsection">
5326 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5327</div>
5328
5329<div class="doc_text">
5330
5331<h5>Syntax:</h5>
5332<p>This is an overloaded intrinsic function. You can use bswap on any integer
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5333type that is an even number of bytes (i.e. BitWidth % 16 == 0).
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5334<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5335 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5336 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5337 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5338</pre>
5339
5340<h5>Overview:</h5>
5341
5342<p>
5343The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5344values with an even number of bytes (positive multiple of 16 bits). These are
5345useful for performing operations on data that is not in the target's native
5346byte order.
5347</p>
5348
5349<h5>Semantics:</h5>
5350
5351<p>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5352The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5353and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5354intrinsic returns an i32 value that has the four bytes of the input i32
5355swapped, 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]5356i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5357<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5358additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
5359</p>
5360
5361</div>
5362
5363<!-- _______________________________________________________________________ -->
5364<div class="doc_subsubsection">
5365 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5366</div>
5367
5368<div class="doc_text">
5369
5370<h5>Syntax:</h5>
5371<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
5372width. Not all targets support all bit widths however.
5373<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5374 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
5375 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5376 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5377 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5378 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5379</pre>
5380
5381<h5>Overview:</h5>
5382
5383<p>
5384The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5385value.
5386</p>
5387
5388<h5>Arguments:</h5>
5389
5390<p>
5391The only argument is the value to be counted. The argument may be of any
5392integer type. The return type must match the argument type.
5393</p>
5394
5395<h5>Semantics:</h5>
5396
5397<p>
5398The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5399</p>
5400</div>
5401
5402<!-- _______________________________________________________________________ -->
5403<div class="doc_subsubsection">
5404 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5405</div>
5406
5407<div class="doc_text">
5408
5409<h5>Syntax:</h5>
5410<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
5411integer bit width. Not all targets support all bit widths however.
5412<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5413 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5414 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5415 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5416 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5417 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5418</pre>
5419
5420<h5>Overview:</h5>
5421
5422<p>
5423The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5424leading zeros in a variable.
5425</p>
5426
5427<h5>Arguments:</h5>
5428
5429<p>
5430The only argument is the value to be counted. The argument may be of any
5431integer type. The return type must match the argument type.
5432</p>
5433
5434<h5>Semantics:</h5>
5435
5436<p>
5437The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5438in a variable. If the src == 0 then the result is the size in bits of the type
5439of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
5440</p>
5441</div>
5442
5443
5444
5445<!-- _______________________________________________________________________ -->
5446<div class="doc_subsubsection">
5447 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5448</div>
5449
5450<div class="doc_text">
5451
5452<h5>Syntax:</h5>
5453<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
5454integer bit width. Not all targets support all bit widths however.
5455<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5456 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5457 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5458 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5459 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5460 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5461</pre>
5462
5463<h5>Overview:</h5>
5464
5465<p>
5466The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5467trailing zeros.
5468</p>
5469
5470<h5>Arguments:</h5>
5471
5472<p>
5473The only argument is the value to be counted. The argument may be of any
5474integer type. The return type must match the argument type.
5475</p>
5476
5477<h5>Semantics:</h5>
5478
5479<p>
5480The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5481in a variable. If the src == 0 then the result is the size in bits of the type
5482of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5483</p>
5484</div>
5485
5486<!-- _______________________________________________________________________ -->
5487<div class="doc_subsubsection">
5488 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
5489</div>
5490
5491<div class="doc_text">
5492
5493<h5>Syntax:</h5>
5494<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
5495on any integer bit width.
5496<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5497 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5498 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5499</pre>
5500
5501<h5>Overview:</h5>
5502<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
5503range of bits from an integer value and returns them in the same bit width as
5504the original value.</p>
5505
5506<h5>Arguments:</h5>
5507<p>The first argument, <tt>%val</tt> and the result may be integer types of
5508any bit width but they must have the same bit width. The second and third
5509arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
5510
5511<h5>Semantics:</h5>
5512<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
5513of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5514<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5515operates in forward mode.</p>
5516<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5517right by <tt>%loBit</tt> bits and then ANDing it with a mask with
5518only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5519<ol>
5520 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5521 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5522 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5523 to determine the number of bits to retain.</li>
5524 <li>A mask of the retained bits is created by shifting a -1 value.</li>
5525 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
5526</ol>
5527<p>In reverse mode, a similar computation is made except that the bits are
5528returned in the reverse order. So, for example, if <tt>X</tt> has the value
5529<tt>i16 0x0ACF (101011001111)</tt> and we apply
5530<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5531<tt>i16 0x0026 (000000100110)</tt>.</p>
5532</div>
5533
5534<div class="doc_subsubsection">
5535 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5536</div>
5537
5538<div class="doc_text">
5539
5540<h5>Syntax:</h5>
5541<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
5542on any integer bit width.
5543<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5544 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5545 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]5546</pre>
5547
5548<h5>Overview:</h5>
5549<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5550of bits in an integer value with another integer value. It returns the integer
5551with the replaced bits.</p>
5552
5553<h5>Arguments:</h5>
5554<p>The first argument, <tt>%val</tt> and the result may be integer types of
5555any bit width but they must have the same bit width. <tt>%val</tt> is the value
5556whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5557integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5558type since they specify only a bit index.</p>
5559
5560<h5>Semantics:</h5>
5561<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5562of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5563<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5564operates in forward mode.</p>
5565<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5566truncating it down to the size of the replacement area or zero extending it
5567up to that size.</p>
5568<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5569are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5570in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
5571to the <tt>%hi</tt>th bit.
5572<p>In reverse mode, a similar computation is made except that the bits are
5573reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
5574<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.
5575<h5>Examples:</h5>
5576<pre>
5577 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
5578 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5579 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5580 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
5581 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
5582</pre>
5583</div>
5584
5585<!-- ======================================================================= -->
5586<div class="doc_subsection">
5587 <a name="int_debugger">Debugger Intrinsics</a>
5588</div>
5589
5590<div class="doc_text">
5591<p>
5592The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5593are described in the <a
5594href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5595Debugging</a> document.
5596</p>
5597</div>
5598
5599
5600<!-- ======================================================================= -->
5601<div class="doc_subsection">
5602 <a name="int_eh">Exception Handling Intrinsics</a>
5603</div>
5604
5605<div class="doc_text">
5606<p> The LLVM exception handling intrinsics (which all start with
5607<tt>llvm.eh.</tt> prefix), are described in the <a
5608href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5609Handling</a> document. </p>
5610</div>
5611
5612<!-- ======================================================================= -->
5613<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5614 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5615</div>
5616
5617<div class="doc_text">
5618<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5619 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5620 the <tt>nest</tt> attribute, from a function. The result is a callable
5621 function pointer lacking the nest parameter - the caller does not need
5622 to provide a value for it. Instead, the value to use is stored in
5623 advance in a "trampoline", a block of memory usually allocated
5624 on the stack, which also contains code to splice the nest value into the
5625 argument list. This is used to implement the GCC nested function address
5626 extension.
5627</p>
5628<p>
5629 For example, if the function is
5630 <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]5631 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]5632<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5633 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5634 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5635 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5636 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5637</pre>
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]5638 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5639 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5640</div>
5641
5642<!-- _______________________________________________________________________ -->
5643<div class="doc_subsubsection">
5644 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5645</div>
5646<div class="doc_text">
5647<h5>Syntax:</h5>
5648<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5649declare 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]5650</pre>
5651<h5>Overview:</h5>
5652<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5653 This fills the memory pointed to by <tt>tramp</tt> with code
5654 and returns a function pointer suitable for executing it.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5655</p>
5656<h5>Arguments:</h5>
5657<p>
5658 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5659 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5660 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sands35012212007-08-22 23:39:54 +0000[diff] [blame]5661 intrinsic. Note that the size and the alignment are target-specific - LLVM
5662 currently provides no portable way of determining them, so a front-end that
5663 generates this intrinsic needs to have some target-specific knowledge.
5664 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]5665</p>
5666<h5>Semantics:</h5>
5667<p>
5668 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5669 dependent code, turning it into a function. A pointer to this function is
5670 returned, but needs to be bitcast to an
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5671 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5672 before being called. The new function's signature is the same as that of
5673 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5674 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5675 of pointer type. Calling the new function is equivalent to calling
5676 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5677 missing <tt>nest</tt> argument. If, after calling
5678 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5679 modified, then the effect of any later call to the returned function pointer is
5680 undefined.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5681</p>
5682</div>
5683
5684<!-- ======================================================================= -->
5685<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5686 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
5687</div>
5688
5689<div class="doc_text">
5690<p>
5691 These intrinsic functions expand the "universal IR" of LLVM to represent
5692 hardware constructs for atomic operations and memory synchronization. This
5693 provides an interface to the hardware, not an interface to the programmer. It
5694 is aimed at a low enough level to allow any programming models or APIs which
5695 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
5696 hardware behavior. Just as hardware provides a "universal IR" for source
5697 languages, it also provides a starting point for developing a "universal"
5698 atomic operation and synchronization IR.
5699</p>
5700<p>
5701 These do <em>not</em> form an API such as high-level threading libraries,
5702 software transaction memory systems, atomic primitives, and intrinsic
5703 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
5704 application libraries. The hardware interface provided by LLVM should allow
5705 a clean implementation of all of these APIs and parallel programming models.
5706 No one model or paradigm should be selected above others unless the hardware
5707 itself ubiquitously does so.
5708
5709</p>
5710</div>
5711
5712<!-- _______________________________________________________________________ -->
5713<div class="doc_subsubsection">
5714 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5715</div>
5716<div class="doc_text">
5717<h5>Syntax:</h5>
5718<pre>
5719declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
5720i1 &lt;device&gt; )
5721
5722</pre>
5723<h5>Overview:</h5>
5724<p>
5725 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5726 specific pairs of memory access types.
5727</p>
5728<h5>Arguments:</h5>
5729<p>
5730 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
5731 The first four arguments enables a specific barrier as listed below. The fith
5732 argument specifies that the barrier applies to io or device or uncached memory.
5733
5734</p>
5735 <ul>
5736 <li><tt>ll</tt>: load-load barrier</li>
5737 <li><tt>ls</tt>: load-store barrier</li>
5738 <li><tt>sl</tt>: store-load barrier</li>
5739 <li><tt>ss</tt>: store-store barrier</li>
5740 <li><tt>device</tt>: barrier applies to device and uncached memory also.
5741 </ul>
5742<h5>Semantics:</h5>
5743<p>
5744 This intrinsic causes the system to enforce some ordering constraints upon
5745 the loads and stores of the program. This barrier does not indicate
5746 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5747 which they occur. For any of the specified pairs of load and store operations
5748 (f.ex. load-load, or store-load), all of the first operations preceding the
5749 barrier will complete before any of the second operations succeeding the
5750 barrier begin. Specifically the semantics for each pairing is as follows:
5751</p>
5752 <ul>
5753 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5754 after the barrier begins.</li>
5755
5756 <li><tt>ls</tt>: All loads before the barrier must complete before any
5757 store after the barrier begins.</li>
5758 <li><tt>ss</tt>: All stores before the barrier must complete before any
5759 store after the barrier begins.</li>
5760 <li><tt>sl</tt>: All stores before the barrier must complete before any
5761 load after the barrier begins.</li>
5762 </ul>
5763<p>
5764 These semantics are applied with a logical "and" behavior when more than one
5765 is enabled in a single memory barrier intrinsic.
5766</p>
5767<p>
5768 Backends may implement stronger barriers than those requested when they do not
5769 support as fine grained a barrier as requested. Some architectures do not
5770 need all types of barriers and on such architectures, these become noops.
5771</p>
5772<h5>Example:</h5>
5773<pre>
5774%ptr = malloc i32
5775 store i32 4, %ptr
5776
5777%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
5778 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
5779 <i>; guarantee the above finishes</i>
5780 store i32 8, %ptr <i>; before this begins</i>
5781</pre>
5782</div>
5783
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5784<!-- _______________________________________________________________________ -->
5785<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5786 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5787</div>
5788<div class="doc_text">
5789<h5>Syntax:</h5>
5790<p>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5791 This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
5792 any integer bit width and for different address spaces. Not all targets
5793 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5794
5795<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5796declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
5797declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
5798declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
5799declare 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]5800
5801</pre>
5802<h5>Overview:</h5>
5803<p>
5804 This loads a value in memory and compares it to a given value. If they are
5805 equal, it stores a new value into the memory.
5806</p>
5807<h5>Arguments:</h5>
5808<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5809 The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5810 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
5811 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
5812 this integer type. While any bit width integer may be used, targets may only
5813 lower representations they support in hardware.
5814
5815</p>
5816<h5>Semantics:</h5>
5817<p>
5818 This entire intrinsic must be executed atomically. It first loads the value
5819 in memory pointed to by <tt>ptr</tt> and compares it with the value
5820 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
5821 loaded value is yielded in all cases. This provides the equivalent of an
5822 atomic compare-and-swap operation within the SSA framework.
5823</p>
5824<h5>Examples:</h5>
5825
5826<pre>
5827%ptr = malloc i32
5828 store i32 4, %ptr
5829
5830%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5831%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5832 <i>; yields {i32}:result1 = 4</i>
5833%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5834%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5835
5836%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5837%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5838 <i>; yields {i32}:result2 = 8</i>
5839%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
5840
5841%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
5842</pre>
5843</div>
5844
5845<!-- _______________________________________________________________________ -->
5846<div class="doc_subsubsection">
5847 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
5848</div>
5849<div class="doc_text">
5850<h5>Syntax:</h5>
5851
5852<p>
5853 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
5854 integer bit width. Not all targets support all bit widths however.</p>
5855<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5856declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
5857declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
5858declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
5859declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5860
5861</pre>
5862<h5>Overview:</h5>
5863<p>
5864 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
5865 the value from memory. It then stores the value in <tt>val</tt> in the memory
5866 at <tt>ptr</tt>.
5867</p>
5868<h5>Arguments:</h5>
5869
5870<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5871 The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5872 <tt>val</tt> argument and the result must be integers of the same bit width.
5873 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
5874 integer type. The targets may only lower integer representations they
5875 support.
5876</p>
5877<h5>Semantics:</h5>
5878<p>
5879 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
5880 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
5881 equivalent of an atomic swap operation within the SSA framework.
5882
5883</p>
5884<h5>Examples:</h5>
5885<pre>
5886%ptr = malloc i32
5887 store i32 4, %ptr
5888
5889%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5890%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5891 <i>; yields {i32}:result1 = 4</i>
5892%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5893%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5894
5895%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5896%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5897 <i>; yields {i32}:result2 = 8</i>
5898
5899%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
5900%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
5901</pre>
5902</div>
5903
5904<!-- _______________________________________________________________________ -->
5905<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5906 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5907
5908</div>
5909<div class="doc_text">
5910<h5>Syntax:</h5>
5911<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5912 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]5913 integer bit width. Not all targets support all bit widths however.</p>
5914<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5915declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
5916declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
5917declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
5918declare 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]5919
5920</pre>
5921<h5>Overview:</h5>
5922<p>
5923 This intrinsic adds <tt>delta</tt> to the value stored in memory at
5924 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
5925</p>
5926<h5>Arguments:</h5>
5927<p>
5928
5929 The intrinsic takes two arguments, the first a pointer to an integer value
5930 and the second an integer value. The result is also an integer value. These
5931 integer types can have any bit width, but they must all have the same bit
5932 width. The targets may only lower integer representations they support.
5933</p>
5934<h5>Semantics:</h5>
5935<p>
5936 This intrinsic does a series of operations atomically. It first loads the
5937 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
5938 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
5939</p>
5940
5941<h5>Examples:</h5>
5942<pre>
5943%ptr = malloc i32
5944 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5945%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5946 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5947%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5948 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5949%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5950 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5951%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5952</pre>
5953</div>
5954
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5955<!-- _______________________________________________________________________ -->
5956<div class="doc_subsubsection">
5957 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
5958
5959</div>
5960<div class="doc_text">
5961<h5>Syntax:</h5>
5962<p>
5963 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]5964 any integer bit width and for different address spaces. Not all targets
5965 support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5966<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5967declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
5968declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
5969declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
5970declare 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]5971
5972</pre>
5973<h5>Overview:</h5>
5974<p>
5975 This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
5976 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
5977</p>
5978<h5>Arguments:</h5>
5979<p>
5980
5981 The intrinsic takes two arguments, the first a pointer to an integer value
5982 and the second an integer value. The result is also an integer value. These
5983 integer types can have any bit width, but they must all have the same bit
5984 width. The targets may only lower integer representations they support.
5985</p>
5986<h5>Semantics:</h5>
5987<p>
5988 This intrinsic does a series of operations atomically. It first loads the
5989 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
5990 result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
5991</p>
5992
5993<h5>Examples:</h5>
5994<pre>
5995%ptr = malloc i32
5996 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5997%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5998 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5999%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6000 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6001%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6002 <i>; yields {i32}:result3 = 2</i>
6003%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6004</pre>
6005</div>
6006
6007<!-- _______________________________________________________________________ -->
6008<div class="doc_subsubsection">
6009 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6010 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6011 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6012 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
6013
6014</div>
6015<div class="doc_text">
6016<h5>Syntax:</h5>
6017<p>
6018 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
6019 <tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6020 <tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
6021 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6022<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6023declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6024declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6025declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6026declare 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]6027
6028</pre>
6029
6030<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6031declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6032declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6033declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6034declare 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]6035
6036</pre>
6037
6038<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6039declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6040declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6041declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6042declare 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]6043
6044</pre>
6045
6046<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6047declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6048declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6049declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6050declare 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]6051
6052</pre>
6053<h5>Overview:</h5>
6054<p>
6055 These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6056 the value stored in memory at <tt>ptr</tt>. It yields the original value
6057 at <tt>ptr</tt>.
6058</p>
6059<h5>Arguments:</h5>
6060<p>
6061
6062 These intrinsics take two arguments, the first a pointer to an integer value
6063 and the second an integer value. The result is also an integer value. These
6064 integer types can have any bit width, but they must all have the same bit
6065 width. The targets may only lower integer representations they support.
6066</p>
6067<h5>Semantics:</h5>
6068<p>
6069 These intrinsics does a series of operations atomically. They first load the
6070 value stored at <tt>ptr</tt>. They then do the bitwise operation
6071 <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
6072 value stored at <tt>ptr</tt>.
6073</p>
6074
6075<h5>Examples:</h5>
6076<pre>
6077%ptr = malloc i32
6078 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6079%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6080 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6081%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6082 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6083%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6084 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6085%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6086 <i>; yields {i32}:result3 = FF</i>
6087%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6088</pre>
6089</div>
6090
6091
6092<!-- _______________________________________________________________________ -->
6093<div class="doc_subsubsection">
6094 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6095 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6096 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6097 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
6098
6099</div>
6100<div class="doc_text">
6101<h5>Syntax:</h5>
6102<p>
6103 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6104 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6105 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6106 address spaces. Not all targets
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6107 support all bit widths however.</p>
6108<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6109declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6110declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6111declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6112declare 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]6113
6114</pre>
6115
6116<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6117declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6118declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6119declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6120declare 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]6121
6122</pre>
6123
6124<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6125declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6126declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6127declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6128declare 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]6129
6130</pre>
6131
6132<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6133declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6134declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6135declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6136declare 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]6137
6138</pre>
6139<h5>Overview:</h5>
6140<p>
6141 These intrinsics takes the signed or unsigned minimum or maximum of
6142 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6143 original value at <tt>ptr</tt>.
6144</p>
6145<h5>Arguments:</h5>
6146<p>
6147
6148 These intrinsics take two arguments, the first a pointer to an integer value
6149 and the second an integer value. The result is also an integer value. These
6150 integer types can have any bit width, but they must all have the same bit
6151 width. The targets may only lower integer representations they support.
6152</p>
6153<h5>Semantics:</h5>
6154<p>
6155 These intrinsics does a series of operations atomically. They first load the
6156 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
6157 <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
6158 the original value stored at <tt>ptr</tt>.
6159</p>
6160
6161<h5>Examples:</h5>
6162<pre>
6163%ptr = malloc i32
6164 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6165%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6166 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6167%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6168 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6169%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6170 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6171%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6172 <i>; yields {i32}:result3 = 8</i>
6173%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6174</pre>
6175</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6176
6177<!-- ======================================================================= -->
6178<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6179 <a name="int_general">General Intrinsics</a>
6180</div>
6181
6182<div class="doc_text">
6183<p> This class of intrinsics is designed to be generic and has
6184no specific purpose. </p>
6185</div>
6186
6187<!-- _______________________________________________________________________ -->
6188<div class="doc_subsubsection">
6189 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6190</div>
6191
6192<div class="doc_text">
6193
6194<h5>Syntax:</h5>
6195<pre>
6196 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6197</pre>
6198
6199<h5>Overview:</h5>
6200
6201<p>
6202The '<tt>llvm.var.annotation</tt>' intrinsic
6203</p>
6204
6205<h5>Arguments:</h5>
6206
6207<p>
6208The first argument is a pointer to a value, the second is a pointer to a
6209global string, the third is a pointer to a global string which is the source
6210file name, and the last argument is the line number.
6211</p>
6212
6213<h5>Semantics:</h5>
6214
6215<p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6216This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6217This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6218annotations. These have no other defined use, they are ignored by code
6219generation and optimization.
6220</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6221</div>
6222
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6223<!-- _______________________________________________________________________ -->
6224<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]6225 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6226</div>
6227
6228<div class="doc_text">
6229
6230<h5>Syntax:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6231<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6232any integer bit width.
6233</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6234<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]6235 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6236 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6237 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6238 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6239 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]6240</pre>
6241
6242<h5>Overview:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6243
6244<p>
6245The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6246</p>
6247
6248<h5>Arguments:</h5>
6249
6250<p>
6251The first argument is an integer value (result of some expression),
6252the second is a pointer to a global string, the third is a pointer to a global
6253string which is the source file name, and the last argument is the line number.
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6254It returns the value of the first argument.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6255</p>
6256
6257<h5>Semantics:</h5>
6258
6259<p>
6260This intrinsic allows annotations to be put on arbitrary expressions
6261with arbitrary strings. This can be useful for special purpose optimizations
6262that want to look for these annotations. These have no other defined use, they
6263are ignored by code generation and optimization.
6264</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6265
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6266<!-- _______________________________________________________________________ -->
6267<div class="doc_subsubsection">
6268 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6269</div>
6270
6271<div class="doc_text">
6272
6273<h5>Syntax:</h5>
6274<pre>
6275 declare void @llvm.trap()
6276</pre>
6277
6278<h5>Overview:</h5>
6279
6280<p>
6281The '<tt>llvm.trap</tt>' intrinsic
6282</p>
6283
6284<h5>Arguments:</h5>
6285
6286<p>
6287None
6288</p>
6289
6290<h5>Semantics:</h5>
6291
6292<p>
6293This intrinsics is lowered to the target dependent trap instruction. If the
6294target does not have a trap instruction, this intrinsic will be lowered to the
6295call of the abort() function.
6296</p>
6297</div>
6298
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6299<!-- *********************************************************************** -->
6300<hr>
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Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6306
6307 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
6308 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
6309 Last modified: $Date$
6310</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]6311
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6312</body>
6313</html>