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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.">
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11</head>
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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>
219 <li><a href="#int_atomic_lcs"><tt>llvm.atomic.lcs</tt></a></li>
220 <li><a href="#int_atomic_las"><tt>llvm.atomic.las</tt></a></li>
221 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]222 </ol>
223 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]224 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]225 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]226 <li><a href="#int_var_annotation">
Tanya Lattner51369f32007-09-22 00:01:26 +0000[diff] [blame]227 <tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]228 <li><a href="#int_annotation">
Tanya Lattner51369f32007-09-22 00:01:26 +0000[diff] [blame]229 <tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]230 <li><a href="#int_trap">
231 <tt>llvm.trap</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]232 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]233 </li>
234 </ol>
235 </li>
236</ol>
237
238<div class="doc_author">
239 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
240 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
241</div>
242
243<!-- *********************************************************************** -->
244<div class="doc_section"> <a name="abstract">Abstract </a></div>
245<!-- *********************************************************************** -->
246
247<div class="doc_text">
248<p>This document is a reference manual for the LLVM assembly language.
249LLVM is an SSA based representation that provides type safety,
250low-level operations, flexibility, and the capability of representing
251'all' high-level languages cleanly. It is the common code
252representation used throughout all phases of the LLVM compilation
253strategy.</p>
254</div>
255
256<!-- *********************************************************************** -->
257<div class="doc_section"> <a name="introduction">Introduction</a> </div>
258<!-- *********************************************************************** -->
259
260<div class="doc_text">
261
262<p>The LLVM code representation is designed to be used in three
263different forms: as an in-memory compiler IR, as an on-disk bitcode
264representation (suitable for fast loading by a Just-In-Time compiler),
265and as a human readable assembly language representation. This allows
266LLVM to provide a powerful intermediate representation for efficient
267compiler transformations and analysis, while providing a natural means
268to debug and visualize the transformations. The three different forms
269of LLVM are all equivalent. This document describes the human readable
270representation and notation.</p>
271
272<p>The LLVM representation aims to be light-weight and low-level
273while being expressive, typed, and extensible at the same time. It
274aims to be a "universal IR" of sorts, by being at a low enough level
275that high-level ideas may be cleanly mapped to it (similar to how
276microprocessors are "universal IR's", allowing many source languages to
277be mapped to them). By providing type information, LLVM can be used as
278the target of optimizations: for example, through pointer analysis, it
279can be proven that a C automatic variable is never accessed outside of
280the current function... allowing it to be promoted to a simple SSA
281value instead of a memory location.</p>
282
283</div>
284
285<!-- _______________________________________________________________________ -->
286<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
287
288<div class="doc_text">
289
290<p>It is important to note that this document describes 'well formed'
291LLVM assembly language. There is a difference between what the parser
292accepts and what is considered 'well formed'. For example, the
293following instruction is syntactically okay, but not well formed:</p>
294
295<div class="doc_code">
296<pre>
297%x = <a href="#i_add">add</a> i32 1, %x
298</pre>
299</div>
300
301<p>...because the definition of <tt>%x</tt> does not dominate all of
302its uses. The LLVM infrastructure provides a verification pass that may
303be used to verify that an LLVM module is well formed. This pass is
304automatically run by the parser after parsing input assembly and by
305the optimizer before it outputs bitcode. The violations pointed out
306by the verifier pass indicate bugs in transformation passes or input to
307the parser.</p>
308</div>
309
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]310<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]311
312<!-- *********************************************************************** -->
313<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
314<!-- *********************************************************************** -->
315
316<div class="doc_text">
317
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]318 <p>LLVM identifiers come in two basic types: global and local. Global
319 identifiers (functions, global variables) begin with the @ character. Local
320 identifiers (register names, types) begin with the % character. Additionally,
321 there are three different formats for identifiers, for different purposes:
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]322
323<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]324 <li>Named values are represented as a string of characters with their prefix.
325 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
326 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]327 Identifiers which require other characters in their names can be surrounded
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]328 with quotes. In this way, anything except a <tt>&quot;</tt> character can
329 be used in a named value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]330
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]331 <li>Unnamed values are represented as an unsigned numeric value with their
332 prefix. For example, %12, @2, %44.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]333
334 <li>Constants, which are described in a <a href="#constants">section about
335 constants</a>, below.</li>
336</ol>
337
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]338<p>LLVM requires that values start with a prefix for two reasons: Compilers
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]339don't need to worry about name clashes with reserved words, and the set of
340reserved words may be expanded in the future without penalty. Additionally,
341unnamed identifiers allow a compiler to quickly come up with a temporary
342variable without having to avoid symbol table conflicts.</p>
343
344<p>Reserved words in LLVM are very similar to reserved words in other
345languages. There are keywords for different opcodes
346('<tt><a href="#i_add">add</a></tt>',
347 '<tt><a href="#i_bitcast">bitcast</a></tt>',
348 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
349href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
350and others. These reserved words cannot conflict with variable names, because
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]351none of them start with a prefix character ('%' or '@').</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]352
353<p>Here is an example of LLVM code to multiply the integer variable
354'<tt>%X</tt>' by 8:</p>
355
356<p>The easy way:</p>
357
358<div class="doc_code">
359<pre>
360%result = <a href="#i_mul">mul</a> i32 %X, 8
361</pre>
362</div>
363
364<p>After strength reduction:</p>
365
366<div class="doc_code">
367<pre>
368%result = <a href="#i_shl">shl</a> i32 %X, i8 3
369</pre>
370</div>
371
372<p>And the hard way:</p>
373
374<div class="doc_code">
375<pre>
376<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
377<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
378%result = <a href="#i_add">add</a> i32 %1, %1
379</pre>
380</div>
381
382<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
383important lexical features of LLVM:</p>
384
385<ol>
386
387 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
388 line.</li>
389
390 <li>Unnamed temporaries are created when the result of a computation is not
391 assigned to a named value.</li>
392
393 <li>Unnamed temporaries are numbered sequentially</li>
394
395</ol>
396
397<p>...and it also shows a convention that we follow in this document. When
398demonstrating instructions, we will follow an instruction with a comment that
399defines the type and name of value produced. Comments are shown in italic
400text.</p>
401
402</div>
403
404<!-- *********************************************************************** -->
405<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
406<!-- *********************************************************************** -->
407
408<!-- ======================================================================= -->
409<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
410</div>
411
412<div class="doc_text">
413
414<p>LLVM programs are composed of "Module"s, each of which is a
415translation unit of the input programs. Each module consists of
416functions, global variables, and symbol table entries. Modules may be
417combined together with the LLVM linker, which merges function (and
418global variable) definitions, resolves forward declarations, and merges
419symbol table entries. Here is an example of the "hello world" module:</p>
420
421<div class="doc_code">
422<pre><i>; Declare the string constant as a global constant...</i>
423<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
424 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
425
426<i>; External declaration of the puts function</i>
427<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
428
429<i>; Definition of main function</i>
430define i32 @main() { <i>; i32()* </i>
431 <i>; Convert [13x i8 ]* to i8 *...</i>
432 %cast210 = <a
433 href="#i_getelementptr">getelementptr</a> [13 x i8 ]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
434
435 <i>; Call puts function to write out the string to stdout...</i>
436 <a
437 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
438 <a
439 href="#i_ret">ret</a> i32 0<br>}<br>
440</pre>
441</div>
442
443<p>This example is made up of a <a href="#globalvars">global variable</a>
444named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
445function, and a <a href="#functionstructure">function definition</a>
446for "<tt>main</tt>".</p>
447
448<p>In general, a module is made up of a list of global values,
449where both functions and global variables are global values. Global values are
450represented by a pointer to a memory location (in this case, a pointer to an
451array of char, and a pointer to a function), and have one of the following <a
452href="#linkage">linkage types</a>.</p>
453
454</div>
455
456<!-- ======================================================================= -->
457<div class="doc_subsection">
458 <a name="linkage">Linkage Types</a>
459</div>
460
461<div class="doc_text">
462
463<p>
464All Global Variables and Functions have one of the following types of linkage:
465</p>
466
467<dl>
468
469 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
470
471 <dd>Global values with internal linkage are only directly accessible by
472 objects in the current module. In particular, linking code into a module with
473 an internal global value may cause the internal to be renamed as necessary to
474 avoid collisions. Because the symbol is internal to the module, all
475 references can be updated. This corresponds to the notion of the
476 '<tt>static</tt>' keyword in C.
477 </dd>
478
479 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
480
481 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
482 the same name when linkage occurs. This is typically used to implement
483 inline functions, templates, or other code which must be generated in each
484 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
485 allowed to be discarded.
486 </dd>
487
488 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
489
490 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
491 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
492 used for globals that may be emitted in multiple translation units, but that
493 are not guaranteed to be emitted into every translation unit that uses them.
494 One example of this are common globals in C, such as "<tt>int X;</tt>" at
495 global scope.
496 </dd>
497
498 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
499
500 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
501 pointer to array type. When two global variables with appending linkage are
502 linked together, the two global arrays are appended together. This is the
503 LLVM, typesafe, equivalent of having the system linker append together
504 "sections" with identical names when .o files are linked.
505 </dd>
506
507 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
508 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
509 until linked, if not linked, the symbol becomes null instead of being an
510 undefined reference.
511 </dd>
512
513 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
514
515 <dd>If none of the above identifiers are used, the global is externally
516 visible, meaning that it participates in linkage and can be used to resolve
517 external symbol references.
518 </dd>
519</dl>
520
521 <p>
522 The next two types of linkage are targeted for Microsoft Windows platform
523 only. They are designed to support importing (exporting) symbols from (to)
524 DLLs.
525 </p>
526
527 <dl>
528 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
529
530 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
531 or variable via a global pointer to a pointer that is set up by the DLL
532 exporting the symbol. On Microsoft Windows targets, the pointer name is
533 formed by combining <code>_imp__</code> and the function or variable name.
534 </dd>
535
536 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
537
538 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
539 pointer to a pointer in a DLL, so that it can be referenced with the
540 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
541 name is formed by combining <code>_imp__</code> and the function or variable
542 name.
543 </dd>
544
545</dl>
546
547<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
548variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
549variable and was linked with this one, one of the two would be renamed,
550preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
551external (i.e., lacking any linkage declarations), they are accessible
552outside of the current module.</p>
553<p>It is illegal for a function <i>declaration</i>
554to have any linkage type other than "externally visible", <tt>dllimport</tt>,
555or <tt>extern_weak</tt>.</p>
556<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
557linkages.
558</div>
559
560<!-- ======================================================================= -->
561<div class="doc_subsection">
562 <a name="callingconv">Calling Conventions</a>
563</div>
564
565<div class="doc_text">
566
567<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
568and <a href="#i_invoke">invokes</a> can all have an optional calling convention
569specified for the call. The calling convention of any pair of dynamic
570caller/callee must match, or the behavior of the program is undefined. The
571following calling conventions are supported by LLVM, and more may be added in
572the future:</p>
573
574<dl>
575 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
576
577 <dd>This calling convention (the default if no other calling convention is
578 specified) matches the target C calling conventions. This calling convention
579 supports varargs function calls and tolerates some mismatch in the declared
580 prototype and implemented declaration of the function (as does normal C).
581 </dd>
582
583 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
584
585 <dd>This calling convention attempts to make calls as fast as possible
586 (e.g. by passing things in registers). This calling convention allows the
587 target to use whatever tricks it wants to produce fast code for the target,
588 without having to conform to an externally specified ABI. Implementations of
Arnold Schwaighofer07444922008-05-14 09:17:12 +0000[diff] [blame]589 this convention should allow arbitrary
590 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> to be
591 supported. This calling convention does not support varargs and requires the
592 prototype of all callees to exactly match the prototype of the function
593 definition.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]594 </dd>
595
596 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
597
598 <dd>This calling convention attempts to make code in the caller as efficient
599 as possible under the assumption that the call is not commonly executed. As
600 such, these calls often preserve all registers so that the call does not break
601 any live ranges in the caller side. This calling convention does not support
602 varargs and requires the prototype of all callees to exactly match the
603 prototype of the function definition.
604 </dd>
605
606 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
607
608 <dd>Any calling convention may be specified by number, allowing
609 target-specific calling conventions to be used. Target specific calling
610 conventions start at 64.
611 </dd>
612</dl>
613
614<p>More calling conventions can be added/defined on an as-needed basis, to
615support pascal conventions or any other well-known target-independent
616convention.</p>
617
618</div>
619
620<!-- ======================================================================= -->
621<div class="doc_subsection">
622 <a name="visibility">Visibility Styles</a>
623</div>
624
625<div class="doc_text">
626
627<p>
628All Global Variables and Functions have one of the following visibility styles:
629</p>
630
631<dl>
632 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
633
634 <dd>On ELF, default visibility means that the declaration is visible to other
635 modules and, in shared libraries, means that the declared entity may be
636 overridden. On Darwin, default visibility means that the declaration is
637 visible to other modules. Default visibility corresponds to "external
638 linkage" in the language.
639 </dd>
640
641 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
642
643 <dd>Two declarations of an object with hidden visibility refer to the same
644 object if they are in the same shared object. Usually, hidden visibility
645 indicates that the symbol will not be placed into the dynamic symbol table,
646 so no other module (executable or shared library) can reference it
647 directly.
648 </dd>
649
650 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
651
652 <dd>On ELF, protected visibility indicates that the symbol will be placed in
653 the dynamic symbol table, but that references within the defining module will
654 bind to the local symbol. That is, the symbol cannot be overridden by another
655 module.
656 </dd>
657</dl>
658
659</div>
660
661<!-- ======================================================================= -->
662<div class="doc_subsection">
663 <a name="globalvars">Global Variables</a>
664</div>
665
666<div class="doc_text">
667
668<p>Global variables define regions of memory allocated at compilation time
669instead of run-time. Global variables may optionally be initialized, may have
670an explicit section to be placed in, and may have an optional explicit alignment
671specified. A variable may be defined as "thread_local", which means that it
672will not be shared by threads (each thread will have a separated copy of the
673variable). A variable may be defined as a global "constant," which indicates
674that the contents of the variable will <b>never</b> be modified (enabling better
675optimization, allowing the global data to be placed in the read-only section of
676an executable, etc). Note that variables that need runtime initialization
677cannot be marked "constant" as there is a store to the variable.</p>
678
679<p>
680LLVM explicitly allows <em>declarations</em> of global variables to be marked
681constant, even if the final definition of the global is not. This capability
682can be used to enable slightly better optimization of the program, but requires
683the language definition to guarantee that optimizations based on the
684'constantness' are valid for the translation units that do not include the
685definition.
686</p>
687
688<p>As SSA values, global variables define pointer values that are in
689scope (i.e. they dominate) all basic blocks in the program. Global
690variables always define a pointer to their "content" type because they
691describe a region of memory, and all memory objects in LLVM are
692accessed through pointers.</p>
693
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]694<p>A global variable may be declared to reside in a target-specifc numbered
695address space. For targets that support them, address spaces may affect how
696optimizations are performed and/or what target instructions are used to access
Christopher Lamb20a39e92007-12-12 08:44:39 +0000[diff] [blame]697the variable. The default address space is zero. The address space qualifier
698must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]699
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]700<p>LLVM allows an explicit section to be specified for globals. If the target
701supports it, it will emit globals to the section specified.</p>
702
703<p>An explicit alignment may be specified for a global. If not present, or if
704the alignment is set to zero, the alignment of the global is set by the target
705to whatever it feels convenient. If an explicit alignment is specified, the
706global is forced to have at least that much alignment. All alignments must be
707a power of 2.</p>
708
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]709<p>For example, the following defines a global in a numbered address space with
710an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]711
712<div class="doc_code">
713<pre>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]714@G = constant float 1.0 addrspace(5), section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]715</pre>
716</div>
717
718</div>
719
720
721<!-- ======================================================================= -->
722<div class="doc_subsection">
723 <a name="functionstructure">Functions</a>
724</div>
725
726<div class="doc_text">
727
728<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
729an optional <a href="#linkage">linkage type</a>, an optional
730<a href="#visibility">visibility style</a>, an optional
731<a href="#callingconv">calling convention</a>, a return type, an optional
732<a href="#paramattrs">parameter attribute</a> for the return type, a function
733name, a (possibly empty) argument list (each with optional
734<a href="#paramattrs">parameter attributes</a>), an optional section, an
Gordon Henriksend606f5b2007-12-10 03:30:21 +0000[diff] [blame]735optional alignment, an optional <a href="#gc">garbage collector name</a>, an
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]736opening curly brace, a list of basic blocks, and a closing curly brace.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]737
738LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
739optional <a href="#linkage">linkage type</a>, an optional
740<a href="#visibility">visibility style</a>, an optional
741<a href="#callingconv">calling convention</a>, a return type, an optional
742<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]743name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksend606f5b2007-12-10 03:30:21 +0000[diff] [blame]744<a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]745
746<p>A function definition contains a list of basic blocks, forming the CFG for
747the function. Each basic block may optionally start with a label (giving the
748basic block a symbol table entry), contains a list of instructions, and ends
749with a <a href="#terminators">terminator</a> instruction (such as a branch or
750function return).</p>
751
752<p>The first basic block in a function is special in two ways: it is immediately
753executed on entrance to the function, and it is not allowed to have predecessor
754basic blocks (i.e. there can not be any branches to the entry block of a
755function). Because the block can have no predecessors, it also cannot have any
756<a href="#i_phi">PHI nodes</a>.</p>
757
758<p>LLVM allows an explicit section to be specified for functions. If the target
759supports it, it will emit functions to the section specified.</p>
760
761<p>An explicit alignment may be specified for a function. If not present, or if
762the alignment is set to zero, the alignment of the function is set by the target
763to whatever it feels convenient. If an explicit alignment is specified, the
764function is forced to have at least that much alignment. All alignments must be
765a power of 2.</p>
766
767</div>
768
769
770<!-- ======================================================================= -->
771<div class="doc_subsection">
772 <a name="aliasstructure">Aliases</a>
773</div>
774<div class="doc_text">
775 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikov96822812008-03-22 08:36:14 +0000[diff] [blame]776 function, global variable, another alias or bitcast of global value). Aliases
777 may have an optional <a href="#linkage">linkage type</a>, and an
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]778 optional <a href="#visibility">visibility style</a>.</p>
779
780 <h5>Syntax:</h5>
781
782<div class="doc_code">
783<pre>
784@&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
785</pre>
786</div>
787
788</div>
789
790
791
792<!-- ======================================================================= -->
793<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
794<div class="doc_text">
795 <p>The return type and each parameter of a function type may have a set of
796 <i>parameter attributes</i> associated with them. Parameter attributes are
797 used to communicate additional information about the result or parameters of
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]798 a function. Parameter attributes are considered to be part of the function,
799 not of the function type, so functions with different parameter attributes
800 can have the same function type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]801
802 <p>Parameter attributes are simple keywords that follow the type specified. If
803 multiple parameter attributes are needed, they are space separated. For
804 example:</p>
805
806<div class="doc_code">
807<pre>
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]808declare i32 @printf(i8* noalias , ...) nounwind
809declare i32 @atoi(i8*) nounwind readonly
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]810</pre>
811</div>
812
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]813 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
814 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]815
816 <p>Currently, only the following parameter attributes are defined:</p>
817 <dl>
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]818 <dt><tt>zeroext</tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]819 <dd>This indicates that the parameter should be zero extended just before
820 a call to this function.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]821
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]822 <dt><tt>signext</tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]823 <dd>This indicates that the parameter should be sign extended just before
824 a call to this function.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]825
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]826 <dt><tt>inreg</tt></dt>
827 <dd>This indicates that the parameter should be placed in register (if
828 possible) during assembling function call. Support for this attribute is
829 target-specific</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]830
831 <dt><tt>byval</tt></dt>
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]832 <dd>This indicates that the pointer parameter should really be passed by
833 value to the function. The attribute implies that a hidden copy of the
834 pointee is made between the caller and the callee, so the callee is unable
835 to modify the value in the callee. This attribute is only valid on llvm
836 pointer arguments. It is generally used to pass structs and arrays by
837 value, but is also valid on scalars (even though this is silly).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]838
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]839 <dt><tt>sret</tt></dt>
Duncan Sands616cc032008-02-18 04:19:38 +0000[diff] [blame]840 <dd>This indicates that the pointer parameter specifies the address of a
841 structure that is the return value of the function in the source program.
Duncan Sandsef0e9e42008-03-17 12:17:41 +0000[diff] [blame]842 Loads and stores to the structure are assumed not to trap.
Duncan Sands616cc032008-02-18 04:19:38 +0000[diff] [blame]843 May only be applied to the first parameter.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]844
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]845 <dt><tt>noalias</tt></dt>
Owen Andersonc4fc4cd2008-02-18 04:09:01 +0000[diff] [blame]846 <dd>This indicates that the parameter does not alias any global or any other
847 parameter. The caller is responsible for ensuring that this is the case,
848 usually by placing the value in a stack allocation.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]849
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]850 <dt><tt>noreturn</tt></dt>
851 <dd>This function attribute indicates that the function never returns. This
852 indicates to LLVM that every call to this function should be treated as if
853 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]854
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]855 <dt><tt>nounwind</tt></dt>
Duncan Sandsef0e9e42008-03-17 12:17:41 +0000[diff] [blame]856 <dd>This function attribute indicates that no exceptions unwind out of the
857 function. Usually this is because the function makes no use of exceptions,
858 but it may also be that the function catches any exceptions thrown when
859 executing it.</dd>
860
Duncan Sands4ee46812007-07-27 19:57:41 +0000[diff] [blame]861 <dt><tt>nest</tt></dt>
862 <dd>This indicates that the parameter can be excised using the
863 <a href="#int_trampoline">trampoline intrinsics</a>.</dd>
Duncan Sands13e13f82007-11-22 20:23:04 +0000[diff] [blame]864 <dt><tt>readonly</tt></dt>
Duncan Sandsd69c0e62007-11-14 21:14:02 +0000[diff] [blame]865 <dd>This function attribute indicates that the function has no side-effects
Duncan Sands13e13f82007-11-22 20:23:04 +0000[diff] [blame]866 except for producing a return value or throwing an exception. The value
867 returned must only depend on the function arguments and/or global variables.
868 It may use values obtained by dereferencing pointers.</dd>
869 <dt><tt>readnone</tt></dt>
870 <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]871 function, but in addition it is not allowed to dereference any pointer arguments
872 or global variables.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]873 </dl>
874
875</div>
876
877<!-- ======================================================================= -->
878<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]879 <a name="gc">Garbage Collector Names</a>
880</div>
881
882<div class="doc_text">
883<p>Each function may specify a garbage collector name, which is simply a
884string.</p>
885
886<div class="doc_code"><pre
887>define void @f() gc "name" { ...</pre></div>
888
889<p>The compiler declares the supported values of <i>name</i>. Specifying a
890collector which will cause the compiler to alter its output in order to support
891the named garbage collection algorithm.</p>
892</div>
893
894<!-- ======================================================================= -->
895<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]896 <a name="moduleasm">Module-Level Inline Assembly</a>
897</div>
898
899<div class="doc_text">
900<p>
901Modules may contain "module-level inline asm" blocks, which corresponds to the
902GCC "file scope inline asm" blocks. These blocks are internally concatenated by
903LLVM and treated as a single unit, but may be separated in the .ll file if
904desired. The syntax is very simple:
905</p>
906
907<div class="doc_code">
908<pre>
909module asm "inline asm code goes here"
910module asm "more can go here"
911</pre>
912</div>
913
914<p>The strings can contain any character by escaping non-printable characters.
915 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
916 for the number.
917</p>
918
919<p>
920 The inline asm code is simply printed to the machine code .s file when
921 assembly code is generated.
922</p>
923</div>
924
925<!-- ======================================================================= -->
926<div class="doc_subsection">
927 <a name="datalayout">Data Layout</a>
928</div>
929
930<div class="doc_text">
931<p>A module may specify a target specific data layout string that specifies how
932data is to be laid out in memory. The syntax for the data layout is simply:</p>
933<pre> target datalayout = "<i>layout specification</i>"</pre>
934<p>The <i>layout specification</i> consists of a list of specifications
935separated by the minus sign character ('-'). Each specification starts with a
936letter and may include other information after the letter to define some
937aspect of the data layout. The specifications accepted are as follows: </p>
938<dl>
939 <dt><tt>E</tt></dt>
940 <dd>Specifies that the target lays out data in big-endian form. That is, the
941 bits with the most significance have the lowest address location.</dd>
942 <dt><tt>e</tt></dt>
943 <dd>Specifies that hte target lays out data in little-endian form. That is,
944 the bits with the least significance have the lowest address location.</dd>
945 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
946 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
947 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
948 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
949 too.</dd>
950 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
951 <dd>This specifies the alignment for an integer type of a given bit
952 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
953 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
954 <dd>This specifies the alignment for a vector type of a given bit
955 <i>size</i>.</dd>
956 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
957 <dd>This specifies the alignment for a floating point type of a given bit
958 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
959 (double).</dd>
960 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
961 <dd>This specifies the alignment for an aggregate type of a given bit
962 <i>size</i>.</dd>
963</dl>
964<p>When constructing the data layout for a given target, LLVM starts with a
965default set of specifications which are then (possibly) overriden by the
966specifications in the <tt>datalayout</tt> keyword. The default specifications
967are given in this list:</p>
968<ul>
969 <li><tt>E</tt> - big endian</li>
970 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
971 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
972 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
973 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
974 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
975 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
976 alignment of 64-bits</li>
977 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
978 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
979 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
980 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
981 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
982</ul>
983<p>When llvm is determining the alignment for a given type, it uses the
984following rules:
985<ol>
986 <li>If the type sought is an exact match for one of the specifications, that
987 specification is used.</li>
988 <li>If no match is found, and the type sought is an integer type, then the
989 smallest integer type that is larger than the bitwidth of the sought type is
990 used. If none of the specifications are larger than the bitwidth then the the
991 largest integer type is used. For example, given the default specifications
992 above, the i7 type will use the alignment of i8 (next largest) while both
993 i65 and i256 will use the alignment of i64 (largest specified).</li>
994 <li>If no match is found, and the type sought is a vector type, then the
995 largest vector type that is smaller than the sought vector type will be used
996 as a fall back. This happens because <128 x double> can be implemented in
997 terms of 64 <2 x double>, for example.</li>
998</ol>
999</div>
1000
1001<!-- *********************************************************************** -->
1002<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1003<!-- *********************************************************************** -->
1004
1005<div class="doc_text">
1006
1007<p>The LLVM type system is one of the most important features of the
1008intermediate representation. Being typed enables a number of
1009optimizations to be performed on the IR directly, without having to do
1010extra analyses on the side before the transformation. A strong type
1011system makes it easier to read the generated code and enables novel
1012analyses and transformations that are not feasible to perform on normal
1013three address code representations.</p>
1014
1015</div>
1016
1017<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1018<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1019Classifications</a> </div>
1020<div class="doc_text">
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1021<p>The types fall into a few useful
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1022classifications:</p>
1023
1024<table border="1" cellspacing="0" cellpadding="4">
1025 <tbody>
1026 <tr><th>Classification</th><th>Types</th></tr>
1027 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1028 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1029 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1030 </tr>
1031 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1032 <td><a href="#t_floating">floating point</a></td>
1033 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1034 </tr>
1035 <tr>
1036 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1037 <td><a href="#t_integer">integer</a>,
1038 <a href="#t_floating">floating point</a>,
1039 <a href="#t_pointer">pointer</a>,
1040 <a href="#t_vector">vector</a>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1041 <a href="#t_struct">structure</a>,
1042 <a href="#t_array">array</a>,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1043 </td>
1044 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1045 <tr>
1046 <td><a href="#t_primitive">primitive</a></td>
1047 <td><a href="#t_label">label</a>,
1048 <a href="#t_void">void</a>,
1049 <a href="#t_integer">integer</a>,
1050 <a href="#t_floating">floating point</a>.</td>
1051 </tr>
1052 <tr>
1053 <td><a href="#t_derived">derived</a></td>
1054 <td><a href="#t_integer">integer</a>,
1055 <a href="#t_array">array</a>,
1056 <a href="#t_function">function</a>,
1057 <a href="#t_pointer">pointer</a>,
1058 <a href="#t_struct">structure</a>,
1059 <a href="#t_pstruct">packed structure</a>,
1060 <a href="#t_vector">vector</a>,
1061 <a href="#t_opaque">opaque</a>.
1062 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1063 </tbody>
1064</table>
1065
1066<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1067most important. Values of these types are the only ones which can be
1068produced by instructions, passed as arguments, or used as operands to
1069instructions. This means that all structures and arrays must be
1070manipulated either by pointer or by component.</p>
1071</div>
1072
1073<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1074<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1075
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1076<div class="doc_text">
1077<p>The primitive types are the fundamental building blocks of the LLVM
1078system.</p>
1079
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1080</div>
1081
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1082<!-- _______________________________________________________________________ -->
1083<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1084
1085<div class="doc_text">
1086 <table>
1087 <tbody>
1088 <tr><th>Type</th><th>Description</th></tr>
1089 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1090 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1091 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1092 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1093 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1094 </tbody>
1095 </table>
1096</div>
1097
1098<!-- _______________________________________________________________________ -->
1099<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1100
1101<div class="doc_text">
1102<h5>Overview:</h5>
1103<p>The void type does not represent any value and has no size.</p>
1104
1105<h5>Syntax:</h5>
1106
1107<pre>
1108 void
1109</pre>
1110</div>
1111
1112<!-- _______________________________________________________________________ -->
1113<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1114
1115<div class="doc_text">
1116<h5>Overview:</h5>
1117<p>The label type represents code labels.</p>
1118
1119<h5>Syntax:</h5>
1120
1121<pre>
1122 label
1123</pre>
1124</div>
1125
1126
1127<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1128<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1129
1130<div class="doc_text">
1131
1132<p>The real power in LLVM comes from the derived types in the system.
1133This is what allows a programmer to represent arrays, functions,
1134pointers, and other useful types. Note that these derived types may be
1135recursive: For example, it is possible to have a two dimensional array.</p>
1136
1137</div>
1138
1139<!-- _______________________________________________________________________ -->
1140<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1141
1142<div class="doc_text">
1143
1144<h5>Overview:</h5>
1145<p>The integer type is a very simple derived type that simply specifies an
1146arbitrary bit width for the integer type desired. Any bit width from 1 bit to
11472^23-1 (about 8 million) can be specified.</p>
1148
1149<h5>Syntax:</h5>
1150
1151<pre>
1152 iN
1153</pre>
1154
1155<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1156value.</p>
1157
1158<h5>Examples:</h5>
1159<table class="layout">
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1160 <tbody>
1161 <tr>
1162 <td><tt>i1</tt></td>
1163 <td>a single-bit integer.</td>
1164 </tr><tr>
1165 <td><tt>i32</tt></td>
1166 <td>a 32-bit integer.</td>
1167 </tr><tr>
1168 <td><tt>i1942652</tt></td>
1169 <td>a really big integer of over 1 million bits.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1170 </tr>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1171 </tbody>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1172</table>
1173</div>
1174
1175<!-- _______________________________________________________________________ -->
1176<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1177
1178<div class="doc_text">
1179
1180<h5>Overview:</h5>
1181
1182<p>The array type is a very simple derived type that arranges elements
1183sequentially in memory. The array type requires a size (number of
1184elements) and an underlying data type.</p>
1185
1186<h5>Syntax:</h5>
1187
1188<pre>
1189 [&lt;# elements&gt; x &lt;elementtype&gt;]
1190</pre>
1191
1192<p>The number of elements is a constant integer value; elementtype may
1193be any type with a size.</p>
1194
1195<h5>Examples:</h5>
1196<table class="layout">
1197 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1198 <td class="left"><tt>[40 x i32]</tt></td>
1199 <td class="left">Array of 40 32-bit integer values.</td>
1200 </tr>
1201 <tr class="layout">
1202 <td class="left"><tt>[41 x i32]</tt></td>
1203 <td class="left">Array of 41 32-bit integer values.</td>
1204 </tr>
1205 <tr class="layout">
1206 <td class="left"><tt>[4 x i8]</tt></td>
1207 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1208 </tr>
1209</table>
1210<p>Here are some examples of multidimensional arrays:</p>
1211<table class="layout">
1212 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1213 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1214 <td class="left">3x4 array of 32-bit integer values.</td>
1215 </tr>
1216 <tr class="layout">
1217 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1218 <td class="left">12x10 array of single precision floating point values.</td>
1219 </tr>
1220 <tr class="layout">
1221 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1222 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1223 </tr>
1224</table>
1225
1226<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1227length array. Normally, accesses past the end of an array are undefined in
1228LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1229As a special case, however, zero length arrays are recognized to be variable
1230length. This allows implementation of 'pascal style arrays' with the LLVM
1231type "{ i32, [0 x float]}", for example.</p>
1232
1233</div>
1234
1235<!-- _______________________________________________________________________ -->
1236<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
1237<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1238
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1239<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1240
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1241<p>The function type can be thought of as a function signature. It
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1242consists of a return type and a list of formal parameter types. The
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1243return 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]1244If 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]1245class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1246
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1247<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1248
1249<pre>
1250 &lt;returntype list&gt; (&lt;parameter list&gt;)
1251</pre>
1252
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1253<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
1254specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1255which indicates that the function takes a variable number of arguments.
1256Variable argument functions can access their arguments with the <a
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1257 href="#int_varargs">variable argument handling intrinsic</a> functions.
1258'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1259<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1260
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1261<h5>Examples:</h5>
1262<table class="layout">
1263 <tr class="layout">
1264 <td class="left"><tt>i32 (i32)</tt></td>
1265 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1266 </td>
1267 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1268 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1269 </tt></td>
1270 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1271 an <tt>i16</tt> that should be sign extended and a
1272 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1273 <tt>float</tt>.
1274 </td>
1275 </tr><tr class="layout">
1276 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1277 <td class="left">A vararg function that takes at least one
1278 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1279 which returns an integer. This is the signature for <tt>printf</tt> in
1280 LLVM.
1281 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1282 </tr><tr class="layout">
1283 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Devang Patel6dddba22008-03-24 18:10:52 +0000[diff] [blame]1284 <td class="left">A function taking an <tt>i32></tt>, returning two
1285 <tt> i32 </tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1286 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1287 </tr>
1288</table>
1289
1290</div>
1291<!-- _______________________________________________________________________ -->
1292<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
1293<div class="doc_text">
1294<h5>Overview:</h5>
1295<p>The structure type is used to represent a collection of data members
1296together in memory. The packing of the field types is defined to match
1297the ABI of the underlying processor. The elements of a structure may
1298be any type that has a size.</p>
1299<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1300and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1301field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1302instruction.</p>
1303<h5>Syntax:</h5>
1304<pre> { &lt;type list&gt; }<br></pre>
1305<h5>Examples:</h5>
1306<table class="layout">
1307 <tr class="layout">
1308 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1309 <td class="left">A triple of three <tt>i32</tt> values</td>
1310 </tr><tr class="layout">
1311 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1312 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1313 second element is a <a href="#t_pointer">pointer</a> to a
1314 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1315 an <tt>i32</tt>.</td>
1316 </tr>
1317</table>
1318</div>
1319
1320<!-- _______________________________________________________________________ -->
1321<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1322</div>
1323<div class="doc_text">
1324<h5>Overview:</h5>
1325<p>The packed structure type is used to represent a collection of data members
1326together in memory. There is no padding between fields. Further, the alignment
1327of a packed structure is 1 byte. The elements of a packed structure may
1328be any type that has a size.</p>
1329<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1330and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1331field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1332instruction.</p>
1333<h5>Syntax:</h5>
1334<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1335<h5>Examples:</h5>
1336<table class="layout">
1337 <tr class="layout">
1338 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1339 <td class="left">A triple of three <tt>i32</tt> values</td>
1340 </tr><tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1341 <td class="left"><tt>&lt; { float, i32 (i32)* } &gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1342 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1343 second element is a <a href="#t_pointer">pointer</a> to a
1344 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1345 an <tt>i32</tt>.</td>
1346 </tr>
1347</table>
1348</div>
1349
1350<!-- _______________________________________________________________________ -->
1351<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
1352<div class="doc_text">
1353<h5>Overview:</h5>
1354<p>As in many languages, the pointer type represents a pointer or
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]1355reference to another object, which must live in memory. Pointer types may have
1356an optional address space attribute defining the target-specific numbered
1357address space where the pointed-to object resides. The default address space is
1358zero.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1359<h5>Syntax:</h5>
1360<pre> &lt;type&gt; *<br></pre>
1361<h5>Examples:</h5>
1362<table class="layout">
1363 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1364 <td class="left"><tt>[4x i32]*</tt></td>
1365 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1366 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1367 </tr>
1368 <tr class="layout">
1369 <td class="left"><tt>i32 (i32 *) *</tt></td>
1370 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1371 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1372 <tt>i32</tt>.</td>
1373 </tr>
1374 <tr class="layout">
1375 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1376 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1377 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1378 </tr>
1379</table>
1380</div>
1381
1382<!-- _______________________________________________________________________ -->
1383<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
1384<div class="doc_text">
1385
1386<h5>Overview:</h5>
1387
1388<p>A vector type is a simple derived type that represents a vector
1389of elements. Vector types are used when multiple primitive data
1390are operated in parallel using a single instruction (SIMD).
1391A vector type requires a size (number of
1392elements) and an underlying primitive data type. Vectors must have a power
1393of two length (1, 2, 4, 8, 16 ...). Vector types are
1394considered <a href="#t_firstclass">first class</a>.</p>
1395
1396<h5>Syntax:</h5>
1397
1398<pre>
1399 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1400</pre>
1401
1402<p>The number of elements is a constant integer value; elementtype may
1403be any integer or floating point type.</p>
1404
1405<h5>Examples:</h5>
1406
1407<table class="layout">
1408 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1409 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1410 <td class="left">Vector of 4 32-bit integer values.</td>
1411 </tr>
1412 <tr class="layout">
1413 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1414 <td class="left">Vector of 8 32-bit floating-point values.</td>
1415 </tr>
1416 <tr class="layout">
1417 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1418 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1419 </tr>
1420</table>
1421</div>
1422
1423<!-- _______________________________________________________________________ -->
1424<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1425<div class="doc_text">
1426
1427<h5>Overview:</h5>
1428
1429<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksenda0706e2007-10-14 00:34:53 +0000[diff] [blame]1430corresponds (for example) to the C notion of a forward declared structure type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1431In LLVM, opaque types can eventually be resolved to any type (not just a
1432structure type).</p>
1433
1434<h5>Syntax:</h5>
1435
1436<pre>
1437 opaque
1438</pre>
1439
1440<h5>Examples:</h5>
1441
1442<table class="layout">
1443 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1444 <td class="left"><tt>opaque</tt></td>
1445 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1446 </tr>
1447</table>
1448</div>
1449
1450
1451<!-- *********************************************************************** -->
1452<div class="doc_section"> <a name="constants">Constants</a> </div>
1453<!-- *********************************************************************** -->
1454
1455<div class="doc_text">
1456
1457<p>LLVM has several different basic types of constants. This section describes
1458them all and their syntax.</p>
1459
1460</div>
1461
1462<!-- ======================================================================= -->
1463<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1464
1465<div class="doc_text">
1466
1467<dl>
1468 <dt><b>Boolean constants</b></dt>
1469
1470 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1471 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
1472 </dd>
1473
1474 <dt><b>Integer constants</b></dt>
1475
1476 <dd>Standard integers (such as '4') are constants of the <a
1477 href="#t_integer">integer</a> type. Negative numbers may be used with
1478 integer types.
1479 </dd>
1480
1481 <dt><b>Floating point constants</b></dt>
1482
1483 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1484 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]1485 notation (see below). The assembler requires the exact decimal value of
1486 a floating-point constant. For example, the assembler accepts 1.25 but
1487 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1488 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1489
1490 <dt><b>Null pointer constants</b></dt>
1491
1492 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
1493 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1494
1495</dl>
1496
1497<p>The one non-intuitive notation for constants is the optional hexadecimal form
1498of floating point constants. For example, the form '<tt>double
14990x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
15004.5e+15</tt>'. The only time hexadecimal floating point constants are required
1501(and the only time that they are generated by the disassembler) is when a
1502floating point constant must be emitted but it cannot be represented as a
1503decimal floating point number. For example, NaN's, infinities, and other
1504special values are represented in their IEEE hexadecimal format so that
1505assembly and disassembly do not cause any bits to change in the constants.</p>
1506
1507</div>
1508
1509<!-- ======================================================================= -->
1510<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1511</div>
1512
1513<div class="doc_text">
1514<p>Aggregate constants arise from aggregation of simple constants
1515and smaller aggregate constants.</p>
1516
1517<dl>
1518 <dt><b>Structure constants</b></dt>
1519
1520 <dd>Structure constants are represented with notation similar to structure
1521 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner6c8de962007-12-25 20:34:52 +0000[diff] [blame]1522 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1523 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]1524 must have <a href="#t_struct">structure type</a>, and the number and
1525 types of elements must match those specified by the type.
1526 </dd>
1527
1528 <dt><b>Array constants</b></dt>
1529
1530 <dd>Array constants are represented with notation similar to array type
1531 definitions (a comma separated list of elements, surrounded by square brackets
1532 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
1533 constants must have <a href="#t_array">array type</a>, and the number and
1534 types of elements must match those specified by the type.
1535 </dd>
1536
1537 <dt><b>Vector constants</b></dt>
1538
1539 <dd>Vector constants are represented with notation similar to vector type
1540 definitions (a comma separated list of elements, surrounded by
1541 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1542 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
1543 href="#t_vector">vector type</a>, and the number and types of elements must
1544 match those specified by the type.
1545 </dd>
1546
1547 <dt><b>Zero initialization</b></dt>
1548
1549 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1550 value to zero of <em>any</em> type, including scalar and aggregate types.
1551 This is often used to avoid having to print large zero initializers (e.g. for
1552 large arrays) and is always exactly equivalent to using explicit zero
1553 initializers.
1554 </dd>
1555</dl>
1556
1557</div>
1558
1559<!-- ======================================================================= -->
1560<div class="doc_subsection">
1561 <a name="globalconstants">Global Variable and Function Addresses</a>
1562</div>
1563
1564<div class="doc_text">
1565
1566<p>The addresses of <a href="#globalvars">global variables</a> and <a
1567href="#functionstructure">functions</a> are always implicitly valid (link-time)
1568constants. These constants are explicitly referenced when the <a
1569href="#identifiers">identifier for the global</a> is used and always have <a
1570href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1571file:</p>
1572
1573<div class="doc_code">
1574<pre>
1575@X = global i32 17
1576@Y = global i32 42
1577@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
1578</pre>
1579</div>
1580
1581</div>
1582
1583<!-- ======================================================================= -->
1584<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
1585<div class="doc_text">
1586 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
1587 no specific value. Undefined values may be of any type and be used anywhere
1588 a constant is permitted.</p>
1589
1590 <p>Undefined values indicate to the compiler that the program is well defined
1591 no matter what value is used, giving the compiler more freedom to optimize.
1592 </p>
1593</div>
1594
1595<!-- ======================================================================= -->
1596<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1597</div>
1598
1599<div class="doc_text">
1600
1601<p>Constant expressions are used to allow expressions involving other constants
1602to be used as constants. Constant expressions may be of any <a
1603href="#t_firstclass">first class</a> type and may involve any LLVM operation
1604that does not have side effects (e.g. load and call are not supported). The
1605following is the syntax for constant expressions:</p>
1606
1607<dl>
1608 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1609 <dd>Truncate a constant to another type. The bit size of CST must be larger
1610 than the bit size of TYPE. Both types must be integers.</dd>
1611
1612 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1613 <dd>Zero extend a constant to another type. The bit size of CST must be
1614 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1615
1616 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1617 <dd>Sign extend a constant to another type. The bit size of CST must be
1618 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1619
1620 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1621 <dd>Truncate a floating point constant to another floating point type. The
1622 size of CST must be larger than the size of TYPE. Both types must be
1623 floating point.</dd>
1624
1625 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1626 <dd>Floating point extend a constant to another type. The size of CST must be
1627 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1628
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]1629 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1630 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1631 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1632 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1633 of the same number of elements. If the value won't fit in the integer type,
1634 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1635
1636 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
1637 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1638 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1639 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1640 of the same number of elements. If the value won't fit in the integer type,
1641 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1642
1643 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
1644 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1645 constant. TYPE must be a scalar or vector floating point type. CST must be of
1646 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1647 of the same number of elements. If the value won't fit in the floating point
1648 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1649
1650 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
1651 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1652 constant. TYPE must be a scalar or vector floating point type. CST must be of
1653 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1654 of the same number of elements. If the value won't fit in the floating point
1655 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1656
1657 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1658 <dd>Convert a pointer typed constant to the corresponding integer constant
1659 TYPE must be an integer type. CST must be of pointer type. The CST value is
1660 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1661
1662 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1663 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1664 pointer type. CST must be of integer type. The CST value is zero extended,
1665 truncated, or unchanged to make it fit in a pointer size. This one is
1666 <i>really</i> dangerous!</dd>
1667
1668 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
1669 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1670 identical (same number of bits). The conversion is done as if the CST value
1671 was stored to memory and read back as TYPE. In other words, no bits change
1672 with this operator, just the type. This can be used for conversion of
1673 vector types to any other type, as long as they have the same bit width. For
1674 pointers it is only valid to cast to another pointer type.
1675 </dd>
1676
1677 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1678
1679 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1680 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1681 instruction, the index list may have zero or more indexes, which are required
1682 to make sense for the type of "CSTPTR".</dd>
1683
1684 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1685
1686 <dd>Perform the <a href="#i_select">select operation</a> on
1687 constants.</dd>
1688
1689 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1690 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1691
1692 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1693 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
1694
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]1695 <dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
1696 <dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
1697
1698 <dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
1699 <dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
1700
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1701 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1702
1703 <dd>Perform the <a href="#i_extractelement">extractelement
1704 operation</a> on constants.
1705
1706 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1707
1708 <dd>Perform the <a href="#i_insertelement">insertelement
1709 operation</a> on constants.</dd>
1710
1711
1712 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1713
1714 <dd>Perform the <a href="#i_shufflevector">shufflevector
1715 operation</a> on constants.</dd>
1716
1717 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1718
1719 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1720 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
1721 binary</a> operations. The constraints on operands are the same as those for
1722 the corresponding instruction (e.g. no bitwise operations on floating point
1723 values are allowed).</dd>
1724</dl>
1725</div>
1726
1727<!-- *********************************************************************** -->
1728<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1729<!-- *********************************************************************** -->
1730
1731<!-- ======================================================================= -->
1732<div class="doc_subsection">
1733<a name="inlineasm">Inline Assembler Expressions</a>
1734</div>
1735
1736<div class="doc_text">
1737
1738<p>
1739LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1740Module-Level Inline Assembly</a>) through the use of a special value. This
1741value represents the inline assembler as a string (containing the instructions
1742to emit), a list of operand constraints (stored as a string), and a flag that
1743indicates whether or not the inline asm expression has side effects. An example
1744inline assembler expression is:
1745</p>
1746
1747<div class="doc_code">
1748<pre>
1749i32 (i32) asm "bswap $0", "=r,r"
1750</pre>
1751</div>
1752
1753<p>
1754Inline assembler expressions may <b>only</b> be used as the callee operand of
1755a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1756</p>
1757
1758<div class="doc_code">
1759<pre>
1760%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
1761</pre>
1762</div>
1763
1764<p>
1765Inline asms with side effects not visible in the constraint list must be marked
1766as having side effects. This is done through the use of the
1767'<tt>sideeffect</tt>' keyword, like so:
1768</p>
1769
1770<div class="doc_code">
1771<pre>
1772call void asm sideeffect "eieio", ""()
1773</pre>
1774</div>
1775
1776<p>TODO: The format of the asm and constraints string still need to be
1777documented here. Constraints on what can be done (e.g. duplication, moving, etc
1778need to be documented).
1779</p>
1780
1781</div>
1782
1783<!-- *********************************************************************** -->
1784<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1785<!-- *********************************************************************** -->
1786
1787<div class="doc_text">
1788
1789<p>The LLVM instruction set consists of several different
1790classifications of instructions: <a href="#terminators">terminator
1791instructions</a>, <a href="#binaryops">binary instructions</a>,
1792<a href="#bitwiseops">bitwise binary instructions</a>, <a
1793 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1794instructions</a>.</p>
1795
1796</div>
1797
1798<!-- ======================================================================= -->
1799<div class="doc_subsection"> <a name="terminators">Terminator
1800Instructions</a> </div>
1801
1802<div class="doc_text">
1803
1804<p>As mentioned <a href="#functionstructure">previously</a>, every
1805basic block in a program ends with a "Terminator" instruction, which
1806indicates which block should be executed after the current block is
1807finished. These terminator instructions typically yield a '<tt>void</tt>'
1808value: they produce control flow, not values (the one exception being
1809the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
1810<p>There are six different terminator instructions: the '<a
1811 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1812instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
1813the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1814 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1815 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
1816
1817</div>
1818
1819<!-- _______________________________________________________________________ -->
1820<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1821Instruction</a> </div>
1822<div class="doc_text">
1823<h5>Syntax:</h5>
1824<pre> ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
1825 ret void <i>; Return from void function</i>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1826 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]1827</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1828
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1829<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1830
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1831<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
1832value) from a function back to the caller.</p>
1833<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1834returns value(s) and then causes control flow, and one that just causes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1835control flow to occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1836
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1837<h5>Arguments:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1838
1839<p>The '<tt>ret</tt>' instruction may return zero, one or multiple values.
1840The type of each return value must be a '<a href="#t_firstclass">first
1841class</a>' type. Note that a function is not <a href="#wellformed">well
1842formed</a> if there exists a '<tt>ret</tt>' instruction inside of the
1843function that returns values that do not match the return type of the
1844function.</p>
1845
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1846<h5>Semantics:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1847
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1848<p>When the '<tt>ret</tt>' instruction is executed, control flow
1849returns back to the calling function's context. If the caller is a "<a
1850 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
1851the instruction after the call. If the caller was an "<a
1852 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
1853at the beginning of the "normal" destination block. If the instruction
1854returns a value, that value shall set the call or invoke instruction's
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1855return value. If the instruction returns multiple values then these
Devang Patelec8a5b02008-03-11 05:51:59 +0000[diff] [blame]1856values can only be accessed through a '<a href="#i_getresult"><tt>getresult</tt>
1857</a>' instruction.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1858
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1859<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1860
1861<pre>
1862 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1863 ret void <i>; Return from a void function</i>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1864 ret i32 4, i8 2 <i>; Return two values 4 and 2 </i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1865</pre>
1866</div>
1867<!-- _______________________________________________________________________ -->
1868<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
1869<div class="doc_text">
1870<h5>Syntax:</h5>
1871<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
1872</pre>
1873<h5>Overview:</h5>
1874<p>The '<tt>br</tt>' instruction is used to cause control flow to
1875transfer to a different basic block in the current function. There are
1876two forms of this instruction, corresponding to a conditional branch
1877and an unconditional branch.</p>
1878<h5>Arguments:</h5>
1879<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
1880single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
1881unconditional form of the '<tt>br</tt>' instruction takes a single
1882'<tt>label</tt>' value as a target.</p>
1883<h5>Semantics:</h5>
1884<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
1885argument is evaluated. If the value is <tt>true</tt>, control flows
1886to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1887control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
1888<h5>Example:</h5>
1889<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
1890 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
1891</div>
1892<!-- _______________________________________________________________________ -->
1893<div class="doc_subsubsection">
1894 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1895</div>
1896
1897<div class="doc_text">
1898<h5>Syntax:</h5>
1899
1900<pre>
1901 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1902</pre>
1903
1904<h5>Overview:</h5>
1905
1906<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1907several different places. It is a generalization of the '<tt>br</tt>'
1908instruction, allowing a branch to occur to one of many possible
1909destinations.</p>
1910
1911
1912<h5>Arguments:</h5>
1913
1914<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1915comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1916an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1917table is not allowed to contain duplicate constant entries.</p>
1918
1919<h5>Semantics:</h5>
1920
1921<p>The <tt>switch</tt> instruction specifies a table of values and
1922destinations. When the '<tt>switch</tt>' instruction is executed, this
1923table is searched for the given value. If the value is found, control flow is
1924transfered to the corresponding destination; otherwise, control flow is
1925transfered to the default destination.</p>
1926
1927<h5>Implementation:</h5>
1928
1929<p>Depending on properties of the target machine and the particular
1930<tt>switch</tt> instruction, this instruction may be code generated in different
1931ways. For example, it could be generated as a series of chained conditional
1932branches or with a lookup table.</p>
1933
1934<h5>Example:</h5>
1935
1936<pre>
1937 <i>; Emulate a conditional br instruction</i>
1938 %Val = <a href="#i_zext">zext</a> i1 %value to i32
1939 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
1940
1941 <i>; Emulate an unconditional br instruction</i>
1942 switch i32 0, label %dest [ ]
1943
1944 <i>; Implement a jump table:</i>
1945 switch i32 %val, label %otherwise [ i32 0, label %onzero
1946 i32 1, label %onone
1947 i32 2, label %ontwo ]
1948</pre>
1949</div>
1950
1951<!-- _______________________________________________________________________ -->
1952<div class="doc_subsubsection">
1953 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1954</div>
1955
1956<div class="doc_text">
1957
1958<h5>Syntax:</h5>
1959
1960<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]1961 &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]1962 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
1963</pre>
1964
1965<h5>Overview:</h5>
1966
1967<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1968function, with the possibility of control flow transfer to either the
1969'<tt>normal</tt>' label or the
1970'<tt>exception</tt>' label. If the callee function returns with the
1971"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1972"normal" label. If the callee (or any indirect callees) returns with the "<a
1973href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1974continued at the dynamically nearest "exception" label. If the callee function
Devang Patelec8a5b02008-03-11 05:51:59 +0000[diff] [blame]1975returns multiple values then individual return values are only accessible through
1976a '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1977
1978<h5>Arguments:</h5>
1979
1980<p>This instruction requires several arguments:</p>
1981
1982<ol>
1983 <li>
1984 The optional "cconv" marker indicates which <a href="#callingconv">calling
1985 convention</a> the call should use. If none is specified, the call defaults
1986 to using C calling conventions.
1987 </li>
1988 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1989 function value being invoked. In most cases, this is a direct function
1990 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1991 an arbitrary pointer to function value.
1992 </li>
1993
1994 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1995 function to be invoked. </li>
1996
1997 <li>'<tt>function args</tt>': argument list whose types match the function
1998 signature argument types. If the function signature indicates the function
1999 accepts a variable number of arguments, the extra arguments can be
2000 specified. </li>
2001
2002 <li>'<tt>normal label</tt>': the label reached when the called function
2003 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2004
2005 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2006 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2007
2008</ol>
2009
2010<h5>Semantics:</h5>
2011
2012<p>This instruction is designed to operate as a standard '<tt><a
2013href="#i_call">call</a></tt>' instruction in most regards. The primary
2014difference is that it establishes an association with a label, which is used by
2015the runtime library to unwind the stack.</p>
2016
2017<p>This instruction is used in languages with destructors to ensure that proper
2018cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2019exception. Additionally, this is important for implementation of
2020'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2021
2022<h5>Example:</h5>
2023<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2024 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2025 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2026 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2027 unwind label %TestCleanup <i>; {i32}:retval set</i>
2028</pre>
2029</div>
2030
2031
2032<!-- _______________________________________________________________________ -->
2033
2034<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2035Instruction</a> </div>
2036
2037<div class="doc_text">
2038
2039<h5>Syntax:</h5>
2040<pre>
2041 unwind
2042</pre>
2043
2044<h5>Overview:</h5>
2045
2046<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2047at the first callee in the dynamic call stack which used an <a
2048href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2049primarily used to implement exception handling.</p>
2050
2051<h5>Semantics:</h5>
2052
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2053<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2054immediately halt. The dynamic call stack is then searched for the first <a
2055href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2056execution continues at the "exceptional" destination block specified by the
2057<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2058dynamic call chain, undefined behavior results.</p>
2059</div>
2060
2061<!-- _______________________________________________________________________ -->
2062
2063<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2064Instruction</a> </div>
2065
2066<div class="doc_text">
2067
2068<h5>Syntax:</h5>
2069<pre>
2070 unreachable
2071</pre>
2072
2073<h5>Overview:</h5>
2074
2075<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2076instruction is used to inform the optimizer that a particular portion of the
2077code is not reachable. This can be used to indicate that the code after a
2078no-return function cannot be reached, and other facts.</p>
2079
2080<h5>Semantics:</h5>
2081
2082<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2083</div>
2084
2085
2086
2087<!-- ======================================================================= -->
2088<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
2089<div class="doc_text">
2090<p>Binary operators are used to do most of the computation in a
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2091program. They require two operands of the same type, execute an operation on them, and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2092produce a single value. The operands might represent
2093multiple 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]2094The result value has the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2095<p>There are several different binary operators:</p>
2096</div>
2097<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2098<div class="doc_subsubsection">
2099 <a name="i_add">'<tt>add</tt>' Instruction</a>
2100</div>
2101
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2102<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2103
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2104<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2105
2106<pre>
2107 &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]2108</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2109
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2110<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2111
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2112<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2113
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2114<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2115
2116<p>The two arguments to the '<tt>add</tt>' instruction must be <a
2117 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
2118 <a href="#t_vector">vector</a> values. Both arguments must have identical
2119 types.</p>
2120
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2121<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2122
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2123<p>The value produced is the integer or floating point sum of the two
2124operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2125
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2126<p>If an integer sum has unsigned overflow, the result returned is the
2127mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2128the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2129
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2130<p>Because LLVM integers use a two's complement representation, this
2131instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2132
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2133<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2134
2135<pre>
2136 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2137</pre>
2138</div>
2139<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2140<div class="doc_subsubsection">
2141 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2142</div>
2143
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2144<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2145
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2146<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2147
2148<pre>
2149 &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]2150</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2151
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2152<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2153
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2154<p>The '<tt>sub</tt>' instruction returns the difference of its two
2155operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2156
2157<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2158'<tt>neg</tt>' instruction present in most other intermediate
2159representations.</p>
2160
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2161<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2162
2163<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
2164 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2165 or <a href="#t_vector">vector</a> values. Both arguments must have identical
2166 types.</p>
2167
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2168<h5>Semantics:</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 value produced is the integer or floating point difference of
2171the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2172
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2173<p>If an integer difference has unsigned overflow, the result returned is the
2174mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2175the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2176
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2177<p>Because LLVM integers use a two's complement representation, this
2178instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2179
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2180<h5>Example:</h5>
2181<pre>
2182 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2183 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2184</pre>
2185</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2186
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2187<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2188<div class="doc_subsubsection">
2189 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2190</div>
2191
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2192<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2193
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2194<h5>Syntax:</h5>
2195<pre> &lt;result&gt; = mul &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2196</pre>
2197<h5>Overview:</h5>
2198<p>The '<tt>mul</tt>' instruction returns the product of its two
2199operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2200
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2201<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2202
2203<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
2204href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2205or <a href="#t_vector">vector</a> values. Both arguments must have identical
2206types.</p>
2207
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2208<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2209
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2210<p>The value produced is the integer or floating point product of the
2211two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2212
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2213<p>If the result of an integer multiplication has unsigned overflow,
2214the result returned is the mathematical result modulo
22152<sup>n</sup>, where n is the bit width of the result.</p>
2216<p>Because LLVM integers use a two's complement representation, and the
2217result is the same width as the operands, this instruction returns the
2218correct result for both signed and unsigned integers. If a full product
2219(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2220should be sign-extended or zero-extended as appropriate to the
2221width of the full product.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2222<h5>Example:</h5>
2223<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
2224</pre>
2225</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2226
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2227<!-- _______________________________________________________________________ -->
2228<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2229</a></div>
2230<div class="doc_text">
2231<h5>Syntax:</h5>
2232<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2233</pre>
2234<h5>Overview:</h5>
2235<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2236operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2237
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2238<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2239
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2240<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2241<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2242values. Both arguments must have identical types.</p>
2243
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2244<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2245
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2246<p>The value produced is the unsigned integer quotient of the two operands.</p>
2247<p>Note that unsigned integer division and signed integer division are distinct
2248operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2249<p>Division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2250<h5>Example:</h5>
2251<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2252</pre>
2253</div>
2254<!-- _______________________________________________________________________ -->
2255<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2256</a> </div>
2257<div class="doc_text">
2258<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2259<pre>
2260 &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]2261</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2262
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2263<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2264
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2265<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2266operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2267
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2268<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2269
2270<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2271<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2272values. Both arguments must have identical types.</p>
2273
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2274<h5>Semantics:</h5>
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2275<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]2276<p>Note that signed integer division and unsigned integer division are distinct
2277operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2278<p>Division by zero leads to undefined behavior. Overflow also leads to
2279undefined behavior; this is a rare case, but can occur, for example,
2280by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2281<h5>Example:</h5>
2282<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2283</pre>
2284</div>
2285<!-- _______________________________________________________________________ -->
2286<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2287Instruction</a> </div>
2288<div class="doc_text">
2289<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2290<pre>
2291 &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]2292</pre>
2293<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2294
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2295<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
2296operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2297
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2298<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2299
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2300<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2301<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2302of floating point values. Both arguments must have identical types.</p>
2303
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2304<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2305
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2306<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2307
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2308<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2309
2310<pre>
2311 &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]2312</pre>
2313</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2314
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2315<!-- _______________________________________________________________________ -->
2316<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2317</div>
2318<div class="doc_text">
2319<h5>Syntax:</h5>
2320<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2321</pre>
2322<h5>Overview:</h5>
2323<p>The '<tt>urem</tt>' instruction returns the remainder from the
2324unsigned division of its two arguments.</p>
2325<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2326<p>The two arguments to the '<tt>urem</tt>' instruction must be
2327<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2328values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2329<h5>Semantics:</h5>
2330<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2331This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2332<p>Note that unsigned integer remainder and signed integer remainder are
2333distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2334<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2335<h5>Example:</h5>
2336<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2337</pre>
2338
2339</div>
2340<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2341<div class="doc_subsubsection">
2342 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2343</div>
2344
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2345<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2346
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2347<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2348
2349<pre>
2350 &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]2351</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2352
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2353<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2354
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2355<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman3e3fd8c2007-11-05 23:35:22 +0000[diff] [blame]2356signed division of its two operands. This instruction can also take
2357<a href="#t_vector">vector</a> versions of the values in which case
2358the elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]2359
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2360<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2361
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2362<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2363<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2364values. Both arguments must have identical types.</p>
2365
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2366<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2367
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2368<p>This instruction returns the <i>remainder</i> of a division (where the result
2369has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2370operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2371a value. For more information about the difference, see <a
2372 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2373Math Forum</a>. For a table of how this is implemented in various languages,
2374please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
2375Wikipedia: modulo operation</a>.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2376<p>Note that signed integer remainder and unsigned integer remainder are
2377distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2378<p>Taking the remainder of a division by zero leads to undefined behavior.
2379Overflow also leads to undefined behavior; this is a rare case, but can occur,
2380for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2381(The remainder doesn't actually overflow, but this rule lets srem be
2382implemented using instructions that return both the result of the division
2383and the remainder.)</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2384<h5>Example:</h5>
2385<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2386</pre>
2387
2388</div>
2389<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2390<div class="doc_subsubsection">
2391 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2392
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2393<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2394
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2395<h5>Syntax:</h5>
2396<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2397</pre>
2398<h5>Overview:</h5>
2399<p>The '<tt>frem</tt>' instruction returns the remainder from the
2400division of its two operands.</p>
2401<h5>Arguments:</h5>
2402<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2403<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2404of floating point values. Both arguments must have identical types.</p>
2405
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2406<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2407
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2408<p>This instruction returns the <i>remainder</i> of a division.
2409The remainder has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2410
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2411<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2412
2413<pre>
2414 &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]2415</pre>
2416</div>
2417
2418<!-- ======================================================================= -->
2419<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2420Operations</a> </div>
2421<div class="doc_text">
2422<p>Bitwise binary operators are used to do various forms of
2423bit-twiddling in a program. They are generally very efficient
2424instructions and can commonly be strength reduced from other
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2425instructions. They require two operands of the same type, execute an operation on them,
2426and 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]2427</div>
2428
2429<!-- _______________________________________________________________________ -->
2430<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2431Instruction</a> </div>
2432<div class="doc_text">
2433<h5>Syntax:</h5>
2434<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2435</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2436
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2437<h5>Overview:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2438
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2439<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2440the left a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2441
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2442<h5>Arguments:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2443
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2444<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2445 href="#t_integer">integer</a> type. '<tt>var2</tt>' is treated as an
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2446unsigned value. This instruction does not support
2447<a href="#t_vector">vector</a> operands.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2448
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2449<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2450
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2451<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup> mod 2<sup>n</sup>,
2452where n is the width of the result. If <tt>var2</tt> is (statically or dynamically) negative or
2453equal 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]2454
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2455<h5>Example:</h5><pre>
2456 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2457 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2458 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2459 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2460</pre>
2461</div>
2462<!-- _______________________________________________________________________ -->
2463<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2464Instruction</a> </div>
2465<div class="doc_text">
2466<h5>Syntax:</h5>
2467<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2468</pre>
2469
2470<h5>Overview:</h5>
2471<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2472operand shifted to the right a specified number of bits with zero fill.</p>
2473
2474<h5>Arguments:</h5>
2475<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2476<a href="#t_integer">integer</a> type. '<tt>var2</tt>' is treated as an
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2477unsigned value. This instruction does not support
2478<a href="#t_vector">vector</a> operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2479
2480<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2481
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2482<p>This instruction always performs a logical shift right operation. The most
2483significant bits of the result will be filled with zero bits after the
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2484shift. If <tt>var2</tt> is (statically or dynamically) equal to or larger than
2485the number of bits in <tt>var1</tt>, the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2486
2487<h5>Example:</h5>
2488<pre>
2489 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2490 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2491 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2492 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2493 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2494</pre>
2495</div>
2496
2497<!-- _______________________________________________________________________ -->
2498<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2499Instruction</a> </div>
2500<div class="doc_text">
2501
2502<h5>Syntax:</h5>
2503<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2504</pre>
2505
2506<h5>Overview:</h5>
2507<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2508operand shifted to the right a specified number of bits with sign extension.</p>
2509
2510<h5>Arguments:</h5>
2511<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2512<a href="#t_integer">integer</a> type. '<tt>var2</tt>' is treated as an
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2513unsigned value. This instruction does not support
2514<a href="#t_vector">vector</a> operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2515
2516<h5>Semantics:</h5>
2517<p>This instruction always performs an arithmetic shift right operation,
2518The most significant bits of the result will be filled with the sign bit
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2519of <tt>var1</tt>. If <tt>var2</tt> is (statically or dynamically) equal to or
2520larger than the number of bits in <tt>var1</tt>, the result is undefined.
2521</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2522
2523<h5>Example:</h5>
2524<pre>
2525 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2526 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2527 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2528 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2529 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2530</pre>
2531</div>
2532
2533<!-- _______________________________________________________________________ -->
2534<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2535Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2536
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2537<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2538
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2539<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2540
2541<pre>
2542 &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]2543</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2544
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2545<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2546
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2547<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2548its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2549
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2550<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2551
2552<p>The two arguments to the '<tt>and</tt>' instruction must be
2553<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2554values. Both arguments must have identical types.</p>
2555
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2556<h5>Semantics:</h5>
2557<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
2558<p> </p>
2559<div style="align: center">
2560<table border="1" cellspacing="0" cellpadding="4">
2561 <tbody>
2562 <tr>
2563 <td>In0</td>
2564 <td>In1</td>
2565 <td>Out</td>
2566 </tr>
2567 <tr>
2568 <td>0</td>
2569 <td>0</td>
2570 <td>0</td>
2571 </tr>
2572 <tr>
2573 <td>0</td>
2574 <td>1</td>
2575 <td>0</td>
2576 </tr>
2577 <tr>
2578 <td>1</td>
2579 <td>0</td>
2580 <td>0</td>
2581 </tr>
2582 <tr>
2583 <td>1</td>
2584 <td>1</td>
2585 <td>1</td>
2586 </tr>
2587 </tbody>
2588</table>
2589</div>
2590<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2591<pre>
2592 &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]2593 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2594 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
2595</pre>
2596</div>
2597<!-- _______________________________________________________________________ -->
2598<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
2599<div class="doc_text">
2600<h5>Syntax:</h5>
2601<pre> &lt;result&gt; = or &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2602</pre>
2603<h5>Overview:</h5>
2604<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2605or of its two operands.</p>
2606<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2607
2608<p>The two arguments to the '<tt>or</tt>' instruction must be
2609<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2610values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2611<h5>Semantics:</h5>
2612<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
2613<p> </p>
2614<div style="align: center">
2615<table border="1" cellspacing="0" cellpadding="4">
2616 <tbody>
2617 <tr>
2618 <td>In0</td>
2619 <td>In1</td>
2620 <td>Out</td>
2621 </tr>
2622 <tr>
2623 <td>0</td>
2624 <td>0</td>
2625 <td>0</td>
2626 </tr>
2627 <tr>
2628 <td>0</td>
2629 <td>1</td>
2630 <td>1</td>
2631 </tr>
2632 <tr>
2633 <td>1</td>
2634 <td>0</td>
2635 <td>1</td>
2636 </tr>
2637 <tr>
2638 <td>1</td>
2639 <td>1</td>
2640 <td>1</td>
2641 </tr>
2642 </tbody>
2643</table>
2644</div>
2645<h5>Example:</h5>
2646<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2647 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2648 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
2649</pre>
2650</div>
2651<!-- _______________________________________________________________________ -->
2652<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2653Instruction</a> </div>
2654<div class="doc_text">
2655<h5>Syntax:</h5>
2656<pre> &lt;result&gt; = xor &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2657</pre>
2658<h5>Overview:</h5>
2659<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2660or of its two operands. The <tt>xor</tt> is used to implement the
2661"one's complement" operation, which is the "~" operator in C.</p>
2662<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2663<p>The two arguments to the '<tt>xor</tt>' instruction must be
2664<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2665values. Both arguments must have identical types.</p>
2666
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2667<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]2668
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2669<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
2670<p> </p>
2671<div style="align: center">
2672<table border="1" cellspacing="0" cellpadding="4">
2673 <tbody>
2674 <tr>
2675 <td>In0</td>
2676 <td>In1</td>
2677 <td>Out</td>
2678 </tr>
2679 <tr>
2680 <td>0</td>
2681 <td>0</td>
2682 <td>0</td>
2683 </tr>
2684 <tr>
2685 <td>0</td>
2686 <td>1</td>
2687 <td>1</td>
2688 </tr>
2689 <tr>
2690 <td>1</td>
2691 <td>0</td>
2692 <td>1</td>
2693 </tr>
2694 <tr>
2695 <td>1</td>
2696 <td>1</td>
2697 <td>0</td>
2698 </tr>
2699 </tbody>
2700</table>
2701</div>
2702<p> </p>
2703<h5>Example:</h5>
2704<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2705 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2706 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2707 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
2708</pre>
2709</div>
2710
2711<!-- ======================================================================= -->
2712<div class="doc_subsection">
2713 <a name="vectorops">Vector Operations</a>
2714</div>
2715
2716<div class="doc_text">
2717
2718<p>LLVM supports several instructions to represent vector operations in a
2719target-independent manner. These instructions cover the element-access and
2720vector-specific operations needed to process vectors effectively. While LLVM
2721does directly support these vector operations, many sophisticated algorithms
2722will want to use target-specific intrinsics to take full advantage of a specific
2723target.</p>
2724
2725</div>
2726
2727<!-- _______________________________________________________________________ -->
2728<div class="doc_subsubsection">
2729 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2730</div>
2731
2732<div class="doc_text">
2733
2734<h5>Syntax:</h5>
2735
2736<pre>
2737 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
2738</pre>
2739
2740<h5>Overview:</h5>
2741
2742<p>
2743The '<tt>extractelement</tt>' instruction extracts a single scalar
2744element from a vector at a specified index.
2745</p>
2746
2747
2748<h5>Arguments:</h5>
2749
2750<p>
2751The first operand of an '<tt>extractelement</tt>' instruction is a
2752value of <a href="#t_vector">vector</a> type. The second operand is
2753an index indicating the position from which to extract the element.
2754The index may be a variable.</p>
2755
2756<h5>Semantics:</h5>
2757
2758<p>
2759The result is a scalar of the same type as the element type of
2760<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2761<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2762results are undefined.
2763</p>
2764
2765<h5>Example:</h5>
2766
2767<pre>
2768 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
2769</pre>
2770</div>
2771
2772
2773<!-- _______________________________________________________________________ -->
2774<div class="doc_subsubsection">
2775 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2776</div>
2777
2778<div class="doc_text">
2779
2780<h5>Syntax:</h5>
2781
2782<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]2783 &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]2784</pre>
2785
2786<h5>Overview:</h5>
2787
2788<p>
2789The '<tt>insertelement</tt>' instruction inserts a scalar
2790element into a vector at a specified index.
2791</p>
2792
2793
2794<h5>Arguments:</h5>
2795
2796<p>
2797The first operand of an '<tt>insertelement</tt>' instruction is a
2798value of <a href="#t_vector">vector</a> type. The second operand is a
2799scalar value whose type must equal the element type of the first
2800operand. The third operand is an index indicating the position at
2801which to insert the value. The index may be a variable.</p>
2802
2803<h5>Semantics:</h5>
2804
2805<p>
2806The result is a vector of the same type as <tt>val</tt>. Its
2807element values are those of <tt>val</tt> except at position
2808<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2809exceeds the length of <tt>val</tt>, the results are undefined.
2810</p>
2811
2812<h5>Example:</h5>
2813
2814<pre>
2815 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
2816</pre>
2817</div>
2818
2819<!-- _______________________________________________________________________ -->
2820<div class="doc_subsubsection">
2821 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2822</div>
2823
2824<div class="doc_text">
2825
2826<h5>Syntax:</h5>
2827
2828<pre>
2829 &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>
2830</pre>
2831
2832<h5>Overview:</h5>
2833
2834<p>
2835The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2836from two input vectors, returning a vector of the same type.
2837</p>
2838
2839<h5>Arguments:</h5>
2840
2841<p>
2842The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2843with types that match each other and types that match the result of the
2844instruction. The third argument is a shuffle mask, which has the same number
2845of elements as the other vector type, but whose element type is always 'i32'.
2846</p>
2847
2848<p>
2849The shuffle mask operand is required to be a constant vector with either
2850constant integer or undef values.
2851</p>
2852
2853<h5>Semantics:</h5>
2854
2855<p>
2856The elements of the two input vectors are numbered from left to right across
2857both of the vectors. The shuffle mask operand specifies, for each element of
2858the result vector, which element of the two input registers the result element
2859gets. The element selector may be undef (meaning "don't care") and the second
2860operand may be undef if performing a shuffle from only one vector.
2861</p>
2862
2863<h5>Example:</h5>
2864
2865<pre>
2866 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
2867 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
2868 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2869 &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.
2870</pre>
2871</div>
2872
2873
2874<!-- ======================================================================= -->
2875<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2876 <a name="aggregateops">Aggregate Operations</a>
2877</div>
2878
2879<div class="doc_text">
2880
2881<p>LLVM supports several instructions for working with aggregate values.
2882</p>
2883
2884</div>
2885
2886<!-- _______________________________________________________________________ -->
2887<div class="doc_subsubsection">
2888 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
2889</div>
2890
2891<div class="doc_text">
2892
2893<h5>Syntax:</h5>
2894
2895<pre>
2896 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
2897</pre>
2898
2899<h5>Overview:</h5>
2900
2901<p>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]2902The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
2903or array element from an aggregate value.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2904</p>
2905
2906
2907<h5>Arguments:</h5>
2908
2909<p>
2910The first operand of an '<tt>extractvalue</tt>' instruction is a
2911value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]2912type. The operands are constant indices to specify which value to extract
2913in the same manner as indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2914'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2915</p>
2916
2917<h5>Semantics:</h5>
2918
2919<p>
2920The result is the value at the position in the aggregate specified by
2921the index operands.
2922</p>
2923
2924<h5>Example:</h5>
2925
2926<pre>
2927 %result = extractvalue {i32, float} %agg, i32 0 <i>; yields i32</i>
2928</pre>
2929</div>
2930
2931
2932<!-- _______________________________________________________________________ -->
2933<div class="doc_subsubsection">
2934 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
2935</div>
2936
2937<div class="doc_text">
2938
2939<h5>Syntax:</h5>
2940
2941<pre>
2942 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
2943</pre>
2944
2945<h5>Overview:</h5>
2946
2947<p>
2948The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]2949into a struct field or array element in an aggregate.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2950</p>
2951
2952
2953<h5>Arguments:</h5>
2954
2955<p>
2956The first operand of an '<tt>insertvalue</tt>' instruction is a
2957value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
2958The second operand is a first-class value to insert.
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]2959type of the first operand. The following operands are constant indices
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2960indicating the position at which to insert the value in the same manner as
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]2961indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2962'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2963The value to insert must have the same type as the value identified
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]2964by the indices.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2965
2966<h5>Semantics:</h5>
2967
2968<p>
2969The result is an aggregate of the same type as <tt>val</tt>. Its
2970value is that of <tt>val</tt> except that the value at the position
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]2971specified by the indices is that of <tt>elt</tt>.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2972</p>
2973
2974<h5>Example:</h5>
2975
2976<pre>
2977 %result = insertvalue {i32, float} %agg, i32 1, i32 0 <i>; yields {i32, float}</i>
2978</pre>
2979</div>
2980
2981
2982<!-- ======================================================================= -->
2983<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2984 <a name="memoryops">Memory Access and Addressing Operations</a>
2985</div>
2986
2987<div class="doc_text">
2988
2989<p>A key design point of an SSA-based representation is how it
2990represents memory. In LLVM, no memory locations are in SSA form, which
2991makes things very simple. This section describes how to read, write,
2992allocate, and free memory in LLVM.</p>
2993
2994</div>
2995
2996<!-- _______________________________________________________________________ -->
2997<div class="doc_subsubsection">
2998 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2999</div>
3000
3001<div class="doc_text">
3002
3003<h5>Syntax:</h5>
3004
3005<pre>
3006 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3007</pre>
3008
3009<h5>Overview:</h5>
3010
3011<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3012heap and returns a pointer to it. The object is always allocated in the generic
3013address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3014
3015<h5>Arguments:</h5>
3016
3017<p>The '<tt>malloc</tt>' instruction allocates
3018<tt>sizeof(&lt;type&gt;)*NumElements</tt>
3019bytes of memory from the operating system and returns a pointer of the
3020appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3021number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3022If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3023be aligned to at least that boundary. If not specified, or if zero, the target can
3024choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3025
3026<p>'<tt>type</tt>' must be a sized type.</p>
3027
3028<h5>Semantics:</h5>
3029
3030<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3031a pointer is returned. The result of a zero byte allocattion is undefined. The
3032result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3033
3034<h5>Example:</h5>
3035
3036<pre>
3037 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
3038
3039 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3040 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3041 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3042 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3043 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3044</pre>
3045</div>
3046
3047<!-- _______________________________________________________________________ -->
3048<div class="doc_subsubsection">
3049 <a name="i_free">'<tt>free</tt>' Instruction</a>
3050</div>
3051
3052<div class="doc_text">
3053
3054<h5>Syntax:</h5>
3055
3056<pre>
3057 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
3058</pre>
3059
3060<h5>Overview:</h5>
3061
3062<p>The '<tt>free</tt>' instruction returns memory back to the unused
3063memory heap to be reallocated in the future.</p>
3064
3065<h5>Arguments:</h5>
3066
3067<p>'<tt>value</tt>' shall be a pointer value that points to a value
3068that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3069instruction.</p>
3070
3071<h5>Semantics:</h5>
3072
3073<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner329d6532008-04-19 22:41:32 +0000[diff] [blame]3074after this instruction executes. If the pointer is null, the operation
3075is a noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3076
3077<h5>Example:</h5>
3078
3079<pre>
3080 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
3081 free [4 x i8]* %array
3082</pre>
3083</div>
3084
3085<!-- _______________________________________________________________________ -->
3086<div class="doc_subsubsection">
3087 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3088</div>
3089
3090<div class="doc_text">
3091
3092<h5>Syntax:</h5>
3093
3094<pre>
3095 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3096</pre>
3097
3098<h5>Overview:</h5>
3099
3100<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3101currently executing function, to be automatically released when this function
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3102returns to its caller. The object is always allocated in the generic address
3103space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3104
3105<h5>Arguments:</h5>
3106
3107<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
3108bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3109appropriate type to the program. If "NumElements" is specified, it is the
3110number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3111If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3112to be aligned to at least that boundary. If not specified, or if zero, the target
3113can choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3114
3115<p>'<tt>type</tt>' may be any sized type.</p>
3116
3117<h5>Semantics:</h5>
3118
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3119<p>Memory is allocated; a pointer is returned. The operation is undefiend if
3120there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3121memory is automatically released when the function returns. The '<tt>alloca</tt>'
3122instruction is commonly used to represent automatic variables that must
3123have an address available. When the function returns (either with the <tt><a
3124 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]3125instructions), the memory is reclaimed. Allocating zero bytes
3126is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3127
3128<h5>Example:</h5>
3129
3130<pre>
3131 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3132 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3133 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3134 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
3135</pre>
3136</div>
3137
3138<!-- _______________________________________________________________________ -->
3139<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3140Instruction</a> </div>
3141<div class="doc_text">
3142<h5>Syntax:</h5>
3143<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>
3144<h5>Overview:</h5>
3145<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
3146<h5>Arguments:</h5>
3147<p>The argument to the '<tt>load</tt>' instruction specifies the memory
3148address from which to load. The pointer must point to a <a
3149 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3150marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
3151the number or order of execution of this <tt>load</tt> with other
3152volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3153instructions. </p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3154<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3155The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3156(that is, the alignment of the memory address). A value of 0 or an
3157omitted "align" argument means that the operation has the preferential
3158alignment for the target. It is the responsibility of the code emitter
3159to ensure that the alignment information is correct. Overestimating
3160the alignment results in an undefined behavior. Underestimating the
3161alignment may produce less efficient code. An alignment of 1 is always
3162safe.
3163</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3164<h5>Semantics:</h5>
3165<p>The location of memory pointed to is loaded.</p>
3166<h5>Examples:</h5>
3167<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3168 <a
3169 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3170 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3171</pre>
3172</div>
3173<!-- _______________________________________________________________________ -->
3174<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3175Instruction</a> </div>
3176<div class="doc_text">
3177<h5>Syntax:</h5>
3178<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3179 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3180</pre>
3181<h5>Overview:</h5>
3182<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
3183<h5>Arguments:</h5>
3184<p>There are two arguments to the '<tt>store</tt>' instruction: a value
3185to 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]3186operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3187of the '<tt>&lt;value&gt;</tt>'
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3188operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
3189optimizer is not allowed to modify the number or order of execution of
3190this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3191 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3192<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3193The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3194(that is, the alignment of the memory address). A value of 0 or an
3195omitted "align" argument means that the operation has the preferential
3196alignment for the target. It is the responsibility of the code emitter
3197to ensure that the alignment information is correct. Overestimating
3198the alignment results in an undefined behavior. Underestimating the
3199alignment may produce less efficient code. An alignment of 1 is always
3200safe.
3201</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3202<h5>Semantics:</h5>
3203<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
3204at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
3205<h5>Example:</h5>
3206<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3207 store i32 3, i32* %ptr <i>; yields {void}</i>
3208 %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]3209</pre>
3210</div>
3211
3212<!-- _______________________________________________________________________ -->
3213<div class="doc_subsubsection">
3214 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3215</div>
3216
3217<div class="doc_text">
3218<h5>Syntax:</h5>
3219<pre>
3220 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
3221</pre>
3222
3223<h5>Overview:</h5>
3224
3225<p>
3226The '<tt>getelementptr</tt>' instruction is used to get the address of a
3227subelement of an aggregate data structure.</p>
3228
3229<h5>Arguments:</h5>
3230
3231<p>This instruction takes a list of integer operands that indicate what
3232elements of the aggregate object to index to. The actual types of the arguments
3233provided depend on the type of the first pointer argument. The
3234'<tt>getelementptr</tt>' instruction is used to index down through the type
3235levels of a structure or to a specific index in an array. When indexing into a
3236structure, only <tt>i32</tt> integer constants are allowed. When indexing
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]3237into an array or pointer, only integers of 32 or 64 bits are allowed; 32-bit
3238values will be sign extended to 64-bits if required.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3239
3240<p>For example, let's consider a C code fragment and how it gets
3241compiled to LLVM:</p>
3242
3243<div class="doc_code">
3244<pre>
3245struct RT {
3246 char A;
3247 int B[10][20];
3248 char C;
3249};
3250struct ST {
3251 int X;
3252 double Y;
3253 struct RT Z;
3254};
3255
3256int *foo(struct ST *s) {
3257 return &amp;s[1].Z.B[5][13];
3258}
3259</pre>
3260</div>
3261
3262<p>The LLVM code generated by the GCC frontend is:</p>
3263
3264<div class="doc_code">
3265<pre>
3266%RT = type { i8 , [10 x [20 x i32]], i8 }
3267%ST = type { i32, double, %RT }
3268
3269define i32* %foo(%ST* %s) {
3270entry:
3271 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3272 ret i32* %reg
3273}
3274</pre>
3275</div>
3276
3277<h5>Semantics:</h5>
3278
3279<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
3280on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
3281and <a href="#t_array">array</a> types can use a 32-bit or 64-bit
3282<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]3283to 64-bits. <a href="#t_struct">Structure</a> and <a href="#t_pstruct">packed
3284structure</a> types require <tt>i32</tt> <b>constants</b>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3285
3286<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
3287type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3288}</tt>' type, a structure. The second index indexes into the third element of
3289the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3290i8 }</tt>' type, another structure. The third index indexes into the second
3291element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3292array. The two dimensions of the array are subscripted into, yielding an
3293'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3294to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
3295
3296<p>Note that it is perfectly legal to index partially through a
3297structure, returning a pointer to an inner element. Because of this,
3298the LLVM code for the given testcase is equivalent to:</p>
3299
3300<pre>
3301 define i32* %foo(%ST* %s) {
3302 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3303 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3304 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3305 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3306 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3307 ret i32* %t5
3308 }
3309</pre>
3310
3311<p>Note that it is undefined to access an array out of bounds: array and
3312pointer indexes must always be within the defined bounds of the array type.
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]3313The one exception for this rule is zero length arrays. These arrays are
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3314defined to be accessible as variable length arrays, which requires access
3315beyond the zero'th element.</p>
3316
3317<p>The getelementptr instruction is often confusing. For some more insight
3318into how it works, see <a href="GetElementPtr.html">the getelementptr
3319FAQ</a>.</p>
3320
3321<h5>Example:</h5>
3322
3323<pre>
3324 <i>; yields [12 x i8]*:aptr</i>
3325 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
3326</pre>
3327</div>
3328
3329<!-- ======================================================================= -->
3330<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3331</div>
3332<div class="doc_text">
3333<p>The instructions in this category are the conversion instructions (casting)
3334which all take a single operand and a type. They perform various bit conversions
3335on the operand.</p>
3336</div>
3337
3338<!-- _______________________________________________________________________ -->
3339<div class="doc_subsubsection">
3340 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3341</div>
3342<div class="doc_text">
3343
3344<h5>Syntax:</h5>
3345<pre>
3346 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3347</pre>
3348
3349<h5>Overview:</h5>
3350<p>
3351The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3352</p>
3353
3354<h5>Arguments:</h5>
3355<p>
3356The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3357be an <a href="#t_integer">integer</a> type, and a type that specifies the size
3358and type of the result, which must be an <a href="#t_integer">integer</a>
3359type. The bit size of <tt>value</tt> must be larger than the bit size of
3360<tt>ty2</tt>. Equal sized types are not allowed.</p>
3361
3362<h5>Semantics:</h5>
3363<p>
3364The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
3365and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3366larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3367It will always truncate bits.</p>
3368
3369<h5>Example:</h5>
3370<pre>
3371 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3372 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3373 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
3374</pre>
3375</div>
3376
3377<!-- _______________________________________________________________________ -->
3378<div class="doc_subsubsection">
3379 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3380</div>
3381<div class="doc_text">
3382
3383<h5>Syntax:</h5>
3384<pre>
3385 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3386</pre>
3387
3388<h5>Overview:</h5>
3389<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3390<tt>ty2</tt>.</p>
3391
3392
3393<h5>Arguments:</h5>
3394<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
3395<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3396also be of <a href="#t_integer">integer</a> type. The bit size of the
3397<tt>value</tt> must be smaller than the bit size of the destination type,
3398<tt>ty2</tt>.</p>
3399
3400<h5>Semantics:</h5>
3401<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
3402bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
3403
3404<p>When zero extending from i1, the result will always be either 0 or 1.</p>
3405
3406<h5>Example:</h5>
3407<pre>
3408 %X = zext i32 257 to i64 <i>; yields i64:257</i>
3409 %Y = zext i1 true to i32 <i>; yields i32:1</i>
3410</pre>
3411</div>
3412
3413<!-- _______________________________________________________________________ -->
3414<div class="doc_subsubsection">
3415 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3416</div>
3417<div class="doc_text">
3418
3419<h5>Syntax:</h5>
3420<pre>
3421 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3422</pre>
3423
3424<h5>Overview:</h5>
3425<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3426
3427<h5>Arguments:</h5>
3428<p>
3429The '<tt>sext</tt>' instruction takes a value to cast, which must be of
3430<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3431also be of <a href="#t_integer">integer</a> type. The bit size of the
3432<tt>value</tt> must be smaller than the bit size of the destination type,
3433<tt>ty2</tt>.</p>
3434
3435<h5>Semantics:</h5>
3436<p>
3437The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3438bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
3439the type <tt>ty2</tt>.</p>
3440
3441<p>When sign extending from i1, the extension always results in -1 or 0.</p>
3442
3443<h5>Example:</h5>
3444<pre>
3445 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
3446 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
3447</pre>
3448</div>
3449
3450<!-- _______________________________________________________________________ -->
3451<div class="doc_subsubsection">
3452 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3453</div>
3454
3455<div class="doc_text">
3456
3457<h5>Syntax:</h5>
3458
3459<pre>
3460 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3461</pre>
3462
3463<h5>Overview:</h5>
3464<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3465<tt>ty2</tt>.</p>
3466
3467
3468<h5>Arguments:</h5>
3469<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3470 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3471cast it to. The size of <tt>value</tt> must be larger than the size of
3472<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3473<i>no-op cast</i>.</p>
3474
3475<h5>Semantics:</h5>
3476<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3477<a href="#t_floating">floating point</a> type to a smaller
3478<a href="#t_floating">floating point</a> type. If the value cannot fit within
3479the destination type, <tt>ty2</tt>, then the results are undefined.</p>
3480
3481<h5>Example:</h5>
3482<pre>
3483 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3484 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3485</pre>
3486</div>
3487
3488<!-- _______________________________________________________________________ -->
3489<div class="doc_subsubsection">
3490 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3491</div>
3492<div class="doc_text">
3493
3494<h5>Syntax:</h5>
3495<pre>
3496 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3497</pre>
3498
3499<h5>Overview:</h5>
3500<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3501floating point value.</p>
3502
3503<h5>Arguments:</h5>
3504<p>The '<tt>fpext</tt>' instruction takes a
3505<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
3506and a <a href="#t_floating">floating point</a> type to cast it to. The source
3507type must be smaller than the destination type.</p>
3508
3509<h5>Semantics:</h5>
3510<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
3511<a href="#t_floating">floating point</a> type to a larger
3512<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
3513used to make a <i>no-op cast</i> because it always changes bits. Use
3514<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
3515
3516<h5>Example:</h5>
3517<pre>
3518 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3519 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3520</pre>
3521</div>
3522
3523<!-- _______________________________________________________________________ -->
3524<div class="doc_subsubsection">
3525 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
3526</div>
3527<div class="doc_text">
3528
3529<h5>Syntax:</h5>
3530<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3531 &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]3532</pre>
3533
3534<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3535<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3536unsigned integer equivalent of type <tt>ty2</tt>.
3537</p>
3538
3539<h5>Arguments:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3540<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]3541scalar or vector <a href="#t_floating">floating point</a> value, and a type
3542to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3543type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3544vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3545
3546<h5>Semantics:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3547<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3548<a href="#t_floating">floating point</a> operand into the nearest (rounding
3549towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3550the results are undefined.</p>
3551
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3552<h5>Example:</h5>
3553<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3554 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3555 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3556 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3557</pre>
3558</div>
3559
3560<!-- _______________________________________________________________________ -->
3561<div class="doc_subsubsection">
3562 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
3563</div>
3564<div class="doc_text">
3565
3566<h5>Syntax:</h5>
3567<pre>
3568 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3569</pre>
3570
3571<h5>Overview:</h5>
3572<p>The '<tt>fptosi</tt>' instruction converts
3573<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
3574</p>
3575
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3576<h5>Arguments:</h5>
3577<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]3578scalar or vector <a href="#t_floating">floating point</a> value, and a type
3579to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3580type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3581vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3582
3583<h5>Semantics:</h5>
3584<p>The '<tt>fptosi</tt>' instruction converts its
3585<a href="#t_floating">floating point</a> operand into the nearest (rounding
3586towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3587the results are undefined.</p>
3588
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3589<h5>Example:</h5>
3590<pre>
3591 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3592 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3593 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
3594</pre>
3595</div>
3596
3597<!-- _______________________________________________________________________ -->
3598<div class="doc_subsubsection">
3599 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
3600</div>
3601<div class="doc_text">
3602
3603<h5>Syntax:</h5>
3604<pre>
3605 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3606</pre>
3607
3608<h5>Overview:</h5>
3609<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
3610integer and converts that value to the <tt>ty2</tt> type.</p>
3611
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3612<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3613<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3614scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3615to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3616type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3617floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3618
3619<h5>Semantics:</h5>
3620<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
3621integer quantity and converts it to the corresponding floating point value. If
3622the value cannot fit in the floating point value, the results are undefined.</p>
3623
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3624<h5>Example:</h5>
3625<pre>
3626 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
3627 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
3628</pre>
3629</div>
3630
3631<!-- _______________________________________________________________________ -->
3632<div class="doc_subsubsection">
3633 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
3634</div>
3635<div class="doc_text">
3636
3637<h5>Syntax:</h5>
3638<pre>
3639 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3640</pre>
3641
3642<h5>Overview:</h5>
3643<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
3644integer and converts that value to the <tt>ty2</tt> type.</p>
3645
3646<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3647<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3648scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3649to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3650type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3651floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3652
3653<h5>Semantics:</h5>
3654<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
3655integer quantity and converts it to the corresponding floating point value. If
3656the value cannot fit in the floating point value, the results are undefined.</p>
3657
3658<h5>Example:</h5>
3659<pre>
3660 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
3661 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
3662</pre>
3663</div>
3664
3665<!-- _______________________________________________________________________ -->
3666<div class="doc_subsubsection">
3667 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3668</div>
3669<div class="doc_text">
3670
3671<h5>Syntax:</h5>
3672<pre>
3673 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3674</pre>
3675
3676<h5>Overview:</h5>
3677<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3678the integer type <tt>ty2</tt>.</p>
3679
3680<h5>Arguments:</h5>
3681<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3682must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
3683<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3684
3685<h5>Semantics:</h5>
3686<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3687<tt>ty2</tt> by interpreting the pointer value as an integer and either
3688truncating or zero extending that value to the size of the integer type. If
3689<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3690<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3691are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3692change.</p>
3693
3694<h5>Example:</h5>
3695<pre>
3696 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3697 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
3698</pre>
3699</div>
3700
3701<!-- _______________________________________________________________________ -->
3702<div class="doc_subsubsection">
3703 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3704</div>
3705<div class="doc_text">
3706
3707<h5>Syntax:</h5>
3708<pre>
3709 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3710</pre>
3711
3712<h5>Overview:</h5>
3713<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3714a pointer type, <tt>ty2</tt>.</p>
3715
3716<h5>Arguments:</h5>
3717<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
3718value to cast, and a type to cast it to, which must be a
3719<a href="#t_pointer">pointer</a> type.
3720
3721<h5>Semantics:</h5>
3722<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3723<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3724the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3725size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3726the size of a pointer then a zero extension is done. If they are the same size,
3727nothing is done (<i>no-op cast</i>).</p>
3728
3729<h5>Example:</h5>
3730<pre>
3731 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3732 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3733 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
3734</pre>
3735</div>
3736
3737<!-- _______________________________________________________________________ -->
3738<div class="doc_subsubsection">
3739 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
3740</div>
3741<div class="doc_text">
3742
3743<h5>Syntax:</h5>
3744<pre>
3745 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3746</pre>
3747
3748<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]3749
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3750<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
3751<tt>ty2</tt> without changing any bits.</p>
3752
3753<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]3754
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3755<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
3756a first class value, and a type to cast it to, which must also be a <a
3757 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
3758and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]3759type is a pointer, the destination type must also be a pointer. This
3760instruction supports bitwise conversion of vectors to integers and to vectors
3761of other types (as long as they have the same size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3762
3763<h5>Semantics:</h5>
3764<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
3765<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3766this conversion. The conversion is done as if the <tt>value</tt> had been
3767stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3768converted to other pointer types with this instruction. To convert pointers to
3769other types, use the <a href="#i_inttoptr">inttoptr</a> or
3770<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
3771
3772<h5>Example:</h5>
3773<pre>
3774 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
3775 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3776 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
3777</pre>
3778</div>
3779
3780<!-- ======================================================================= -->
3781<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3782<div class="doc_text">
3783<p>The instructions in this category are the "miscellaneous"
3784instructions, which defy better classification.</p>
3785</div>
3786
3787<!-- _______________________________________________________________________ -->
3788<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3789</div>
3790<div class="doc_text">
3791<h5>Syntax:</h5>
3792<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
3793</pre>
3794<h5>Overview:</h5>
3795<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3796of its two integer or pointer operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3797<h5>Arguments:</h5>
3798<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
3799the condition code indicating the kind of comparison to perform. It is not
3800a value, just a keyword. The possible condition code are:
3801<ol>
3802 <li><tt>eq</tt>: equal</li>
3803 <li><tt>ne</tt>: not equal </li>
3804 <li><tt>ugt</tt>: unsigned greater than</li>
3805 <li><tt>uge</tt>: unsigned greater or equal</li>
3806 <li><tt>ult</tt>: unsigned less than</li>
3807 <li><tt>ule</tt>: unsigned less or equal</li>
3808 <li><tt>sgt</tt>: signed greater than</li>
3809 <li><tt>sge</tt>: signed greater or equal</li>
3810 <li><tt>slt</tt>: signed less than</li>
3811 <li><tt>sle</tt>: signed less or equal</li>
3812</ol>
3813<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
3814<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
3815<h5>Semantics:</h5>
3816<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3817the condition code given as <tt>cond</tt>. The comparison performed always
3818yields a <a href="#t_primitive">i1</a> result, as follows:
3819<ol>
3820 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3821 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3822 </li>
3823 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3824 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3825 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3826 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3827 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3828 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3829 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3830 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3831 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3832 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3833 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3834 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3835 <li><tt>sge</tt>: interprets the operands as signed values and yields
3836 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3837 <li><tt>slt</tt>: interprets the operands as signed values and yields
3838 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3839 <li><tt>sle</tt>: interprets the operands as signed values and yields
3840 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3841</ol>
3842<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
3843values are compared as if they were integers.</p>
3844
3845<h5>Example:</h5>
3846<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3847 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3848 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3849 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3850 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3851 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
3852</pre>
3853</div>
3854
3855<!-- _______________________________________________________________________ -->
3856<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3857</div>
3858<div class="doc_text">
3859<h5>Syntax:</h5>
3860<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
3861</pre>
3862<h5>Overview:</h5>
3863<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3864of its floating point operands.</p>
3865<h5>Arguments:</h5>
3866<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
3867the condition code indicating the kind of comparison to perform. It is not
3868a value, just a keyword. The possible condition code are:
3869<ol>
3870 <li><tt>false</tt>: no comparison, always returns false</li>
3871 <li><tt>oeq</tt>: ordered and equal</li>
3872 <li><tt>ogt</tt>: ordered and greater than </li>
3873 <li><tt>oge</tt>: ordered and greater than or equal</li>
3874 <li><tt>olt</tt>: ordered and less than </li>
3875 <li><tt>ole</tt>: ordered and less than or equal</li>
3876 <li><tt>one</tt>: ordered and not equal</li>
3877 <li><tt>ord</tt>: ordered (no nans)</li>
3878 <li><tt>ueq</tt>: unordered or equal</li>
3879 <li><tt>ugt</tt>: unordered or greater than </li>
3880 <li><tt>uge</tt>: unordered or greater than or equal</li>
3881 <li><tt>ult</tt>: unordered or less than </li>
3882 <li><tt>ule</tt>: unordered or less than or equal</li>
3883 <li><tt>une</tt>: unordered or not equal</li>
3884 <li><tt>uno</tt>: unordered (either nans)</li>
3885 <li><tt>true</tt>: no comparison, always returns true</li>
3886</ol>
3887<p><i>Ordered</i> means that neither operand is a QNAN while
3888<i>unordered</i> means that either operand may be a QNAN.</p>
3889<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3890<a href="#t_floating">floating point</a> typed. They must have identical
3891types.</p>
3892<h5>Semantics:</h5>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]3893<p>The '<tt>fcmp</tt>' instruction compares <tt>var1</tt> and <tt>var2</tt>
3894according to the condition code given as <tt>cond</tt>. The comparison performed
3895always yields a <a href="#t_primitive">i1</a> result, as follows:
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3896<ol>
3897 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
3898 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
3899 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
3900 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
3901 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
3902 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
3903 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3904 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
3905 <tt>var1</tt> is less than <tt>var2</tt>.</li>
3906 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
3907 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3908 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
3909 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
3910 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3911 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
3912 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
3913 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
3914 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3915 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
3916 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3917 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
3918 <tt>var1</tt> is less than <tt>var2</tt>.</li>
3919 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
3920 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3921 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
3922 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
3923 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
3924 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3925</ol>
3926
3927<h5>Example:</h5>
3928<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3929 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3930 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3931 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3932</pre>
3933</div>
3934
3935<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]3936<div class="doc_subsubsection">
3937 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
3938</div>
3939<div class="doc_text">
3940<h5>Syntax:</h5>
3941<pre> &lt;result&gt; = vicmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
3942</pre>
3943<h5>Overview:</h5>
3944<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
3945element-wise comparison of its two integer vector operands.</p>
3946<h5>Arguments:</h5>
3947<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
3948the condition code indicating the kind of comparison to perform. It is not
3949a value, just a keyword. The possible condition code are:
3950<ol>
3951 <li><tt>eq</tt>: equal</li>
3952 <li><tt>ne</tt>: not equal </li>
3953 <li><tt>ugt</tt>: unsigned greater than</li>
3954 <li><tt>uge</tt>: unsigned greater or equal</li>
3955 <li><tt>ult</tt>: unsigned less than</li>
3956 <li><tt>ule</tt>: unsigned less or equal</li>
3957 <li><tt>sgt</tt>: signed greater than</li>
3958 <li><tt>sge</tt>: signed greater or equal</li>
3959 <li><tt>slt</tt>: signed less than</li>
3960 <li><tt>sle</tt>: signed less or equal</li>
3961</ol>
3962<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
3963<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
3964<h5>Semantics:</h5>
3965<p>The '<tt>vicmp</tt>' instruction compares <tt>var1</tt> and <tt>var2</tt>
3966according to the condition code given as <tt>cond</tt>. The comparison yields a
3967<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
3968identical type as the values being compared. The most significant bit in each
3969element is 1 if the element-wise comparison evaluates to true, and is 0
3970otherwise. All other bits of the result are undefined. The condition codes
3971are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
3972instruction</a>.
3973
3974<h5>Example:</h5>
3975<pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]3976 &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>
3977 &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]3978</pre>
3979</div>
3980
3981<!-- _______________________________________________________________________ -->
3982<div class="doc_subsubsection">
3983 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
3984</div>
3985<div class="doc_text">
3986<h5>Syntax:</h5>
3987<pre> &lt;result&gt; = vfcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt;</pre>
3988<h5>Overview:</h5>
3989<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
3990element-wise comparison of its two floating point vector operands. The output
3991elements have the same width as the input elements.</p>
3992<h5>Arguments:</h5>
3993<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
3994the condition code indicating the kind of comparison to perform. It is not
3995a value, just a keyword. The possible condition code are:
3996<ol>
3997 <li><tt>false</tt>: no comparison, always returns false</li>
3998 <li><tt>oeq</tt>: ordered and equal</li>
3999 <li><tt>ogt</tt>: ordered and greater than </li>
4000 <li><tt>oge</tt>: ordered and greater than or equal</li>
4001 <li><tt>olt</tt>: ordered and less than </li>
4002 <li><tt>ole</tt>: ordered and less than or equal</li>
4003 <li><tt>one</tt>: ordered and not equal</li>
4004 <li><tt>ord</tt>: ordered (no nans)</li>
4005 <li><tt>ueq</tt>: unordered or equal</li>
4006 <li><tt>ugt</tt>: unordered or greater than </li>
4007 <li><tt>uge</tt>: unordered or greater than or equal</li>
4008 <li><tt>ult</tt>: unordered or less than </li>
4009 <li><tt>ule</tt>: unordered or less than or equal</li>
4010 <li><tt>une</tt>: unordered or not equal</li>
4011 <li><tt>uno</tt>: unordered (either nans)</li>
4012 <li><tt>true</tt>: no comparison, always returns true</li>
4013</ol>
4014<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4015<a href="#t_floating">floating point</a> typed. They must also be identical
4016types.</p>
4017<h5>Semantics:</h5>
4018<p>The '<tt>vfcmp</tt>' instruction compares <tt>var1</tt> and <tt>var2</tt>
4019according to the condition code given as <tt>cond</tt>. The comparison yields a
4020<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4021an identical number of elements as the values being compared, and each element
4022having identical with to the width of the floating point elements. The most
4023significant bit in each element is 1 if the element-wise comparison evaluates to
4024true, and is 0 otherwise. All other bits of the result are undefined. The
4025condition codes are evaluated identically to the
4026<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.
4027
4028<h5>Example:</h5>
4029<pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]4030 &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>
4031 &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]4032</pre>
4033</div>
4034
4035<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]4036<div class="doc_subsubsection">
4037 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4038</div>
4039
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4040<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]4041
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4042<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]4043
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4044<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4045<h5>Overview:</h5>
4046<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4047the SSA graph representing the function.</p>
4048<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]4049
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4050<p>The type of the incoming values is specified with the first type
4051field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4052as arguments, with one pair for each predecessor basic block of the
4053current block. Only values of <a href="#t_firstclass">first class</a>
4054type may be used as the value arguments to the PHI node. Only labels
4055may be used as the label arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]4056
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4057<p>There must be no non-phi instructions between the start of a basic
4058block and the PHI instructions: i.e. PHI instructions must be first in
4059a basic block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]4060
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4061<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]4062
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4063<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4064specified by the pair corresponding to the predecessor basic block that executed
4065just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]4066
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4067<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]4068<pre>
4069Loop: ; Infinite loop that counts from 0 on up...
4070 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4071 %nextindvar = add i32 %indvar, 1
4072 br label %Loop
4073</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4074</div>
4075
4076<!-- _______________________________________________________________________ -->
4077<div class="doc_subsubsection">
4078 <a name="i_select">'<tt>select</tt>' Instruction</a>
4079</div>
4080
4081<div class="doc_text">
4082
4083<h5>Syntax:</h5>
4084
4085<pre>
4086 &lt;result&gt; = select i1 &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
4087</pre>
4088
4089<h5>Overview:</h5>
4090
4091<p>
4092The '<tt>select</tt>' instruction is used to choose one value based on a
4093condition, without branching.
4094</p>
4095
4096
4097<h5>Arguments:</h5>
4098
4099<p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]4100The '<tt>select</tt>' instruction requires an 'i1' value indicating the
4101condition, and two values of the same <a href="#t_firstclass">first class</a>
4102type. If the val1/val2 are vectors, the entire vectors are selected, not
4103individual elements.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4104</p>
4105
4106<h5>Semantics:</h5>
4107
4108<p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame^]4109If the i1 condition evaluates is 1, the instruction returns the first
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4110value argument; otherwise, it returns the second value argument.
4111</p>
4112
4113<h5>Example:</h5>
4114
4115<pre>
4116 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4117</pre>
4118</div>
4119
4120
4121<!-- _______________________________________________________________________ -->
4122<div class="doc_subsubsection">
4123 <a name="i_call">'<tt>call</tt>' Instruction</a>
4124</div>
4125
4126<div class="doc_text">
4127
4128<h5>Syntax:</h5>
4129<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4130 &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]4131</pre>
4132
4133<h5>Overview:</h5>
4134
4135<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4136
4137<h5>Arguments:</h5>
4138
4139<p>This instruction requires several arguments:</p>
4140
4141<ol>
4142 <li>
4143 <p>The optional "tail" marker indicates whether the callee function accesses
4144 any allocas or varargs in the caller. If the "tail" marker is present, the
4145 function call is eligible for tail call optimization. Note that calls may
4146 be marked "tail" even if they do not occur before a <a
4147 href="#i_ret"><tt>ret</tt></a> instruction.
4148 </li>
4149 <li>
4150 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
4151 convention</a> the call should use. If none is specified, the call defaults
4152 to using C calling conventions.
4153 </li>
4154 <li>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4155 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4156 the type of the return value. Functions that return no value are marked
4157 <tt><a href="#t_void">void</a></tt>.</p>
4158 </li>
4159 <li>
4160 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4161 value being invoked. The argument types must match the types implied by
4162 this signature. This type can be omitted if the function is not varargs
4163 and if the function type does not return a pointer to a function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4164 </li>
4165 <li>
4166 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4167 be invoked. In most cases, this is a direct function invocation, but
4168 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4169 to function value.</p>
4170 </li>
4171 <li>
4172 <p>'<tt>function args</tt>': argument list whose types match the
4173 function signature argument types. All arguments must be of
4174 <a href="#t_firstclass">first class</a> type. If the function signature
4175 indicates the function accepts a variable number of arguments, the extra
4176 arguments can be specified.</p>
4177 </li>
4178</ol>
4179
4180<h5>Semantics:</h5>
4181
4182<p>The '<tt>call</tt>' instruction is used to cause control flow to
4183transfer to a specified function, with its incoming arguments bound to
4184the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4185instruction in the called function, control flow continues with the
4186instruction after the function call, and the return value of the
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4187function is bound to the result argument. If the callee returns multiple
4188values then the return values of the function are only accessible through
4189the '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4190
4191<h5>Example:</h5>
4192
4193<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4194 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4195 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4196 %X = tail call i32 @foo() <i>; yields i32</i>
4197 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4198 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4199
4200 %struct.A = type { i32, i8 }
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4201 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
4202 %gr = getresult %struct.A %r, 0 <i>; yields i32</i>
4203 %gr1 = getresult %struct.A %r, 1 <i>; yields i8</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4204</pre>
4205
4206</div>
4207
4208<!-- _______________________________________________________________________ -->
4209<div class="doc_subsubsection">
4210 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4211</div>
4212
4213<div class="doc_text">
4214
4215<h5>Syntax:</h5>
4216
4217<pre>
4218 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4219</pre>
4220
4221<h5>Overview:</h5>
4222
4223<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
4224the "variable argument" area of a function call. It is used to implement the
4225<tt>va_arg</tt> macro in C.</p>
4226
4227<h5>Arguments:</h5>
4228
4229<p>This instruction takes a <tt>va_list*</tt> value and the type of
4230the argument. It returns a value of the specified argument type and
4231increments the <tt>va_list</tt> to point to the next argument. The
4232actual type of <tt>va_list</tt> is target specific.</p>
4233
4234<h5>Semantics:</h5>
4235
4236<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4237type from the specified <tt>va_list</tt> and causes the
4238<tt>va_list</tt> to point to the next argument. For more information,
4239see the variable argument handling <a href="#int_varargs">Intrinsic
4240Functions</a>.</p>
4241
4242<p>It is legal for this instruction to be called in a function which does not
4243take a variable number of arguments, for example, the <tt>vfprintf</tt>
4244function.</p>
4245
4246<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
4247href="#intrinsics">intrinsic function</a> because it takes a type as an
4248argument.</p>
4249
4250<h5>Example:</h5>
4251
4252<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4253
4254</div>
4255
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4256<!-- _______________________________________________________________________ -->
4257<div class="doc_subsubsection">
4258 <a name="i_getresult">'<tt>getresult</tt>' Instruction</a>
4259</div>
4260
4261<div class="doc_text">
4262
4263<h5>Syntax:</h5>
4264<pre>
Chris Lattneree9da3f2008-03-21 17:20:51 +0000[diff] [blame]4265 &lt;resultval&gt; = getresult &lt;type&gt; &lt;retval&gt;, &lt;index&gt;
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4266</pre>
Chris Lattneree9da3f2008-03-21 17:20:51 +0000[diff] [blame]4267
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4268<h5>Overview:</h5>
4269
4270<p> The '<tt>getresult</tt>' instruction is used to extract individual values
Chris Lattneree9da3f2008-03-21 17:20:51 +0000[diff] [blame]4271from a '<tt><a href="#i_call">call</a></tt>'
4272or '<tt><a href="#i_invoke">invoke</a></tt>' instruction that returns multiple
4273results.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4274
4275<h5>Arguments:</h5>
4276
Chris Lattneree9da3f2008-03-21 17:20:51 +0000[diff] [blame]4277<p>The '<tt>getresult</tt>' instruction takes a call or invoke value as its
Chris Lattnerd8dd3522008-04-23 04:06:52 +0000[diff] [blame]4278first argument, or an undef value. The value must have <a
4279href="#t_struct">structure type</a>. The second argument is a constant
4280unsigned index value which must be in range for the number of values returned
4281by the call.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4282
4283<h5>Semantics:</h5>
4284
Chris Lattneree9da3f2008-03-21 17:20:51 +0000[diff] [blame]4285<p>The '<tt>getresult</tt>' instruction extracts the element identified by
4286'<tt>index</tt>' from the aggregate value.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4287
4288<h5>Example:</h5>
4289
4290<pre>
4291 %struct.A = type { i32, i8 }
4292
4293 %r = call %struct.A @foo()
Chris Lattneree9da3f2008-03-21 17:20:51 +0000[diff] [blame]4294 %gr = getresult %struct.A %r, 0 <i>; yields i32:%gr</i>
4295 %gr1 = getresult %struct.A %r, 1 <i>; yields i8:%gr1</i>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4296 add i32 %gr, 42
4297 add i8 %gr1, 41
4298</pre>
4299
4300</div>
4301
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4302<!-- *********************************************************************** -->
4303<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4304<!-- *********************************************************************** -->
4305
4306<div class="doc_text">
4307
4308<p>LLVM supports the notion of an "intrinsic function". These functions have
4309well known names and semantics and are required to follow certain restrictions.
4310Overall, these intrinsics represent an extension mechanism for the LLVM
4311language that does not require changing all of the transformations in LLVM when
4312adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
4313
4314<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
4315prefix is reserved in LLVM for intrinsic names; thus, function names may not
4316begin with this prefix. Intrinsic functions must always be external functions:
4317you cannot define the body of intrinsic functions. Intrinsic functions may
4318only be used in call or invoke instructions: it is illegal to take the address
4319of an intrinsic function. Additionally, because intrinsic functions are part
4320of the LLVM language, it is required if any are added that they be documented
4321here.</p>
4322
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4323<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4324a family of functions that perform the same operation but on different data
4325types. Because LLVM can represent over 8 million different integer types,
4326overloading is used commonly to allow an intrinsic function to operate on any
4327integer type. One or more of the argument types or the result type can be
4328overloaded to accept any integer type. Argument types may also be defined as
4329exactly matching a previous argument's type or the result type. This allows an
4330intrinsic function which accepts multiple arguments, but needs all of them to
4331be of the same type, to only be overloaded with respect to a single argument or
4332the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4333
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4334<p>Overloaded intrinsics will have the names of its overloaded argument types
4335encoded into its function name, each preceded by a period. Only those types
4336which are overloaded result in a name suffix. Arguments whose type is matched
4337against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4338take an integer of any width and returns an integer of exactly the same integer
4339width. This leads to a family of functions such as
4340<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4341Only one type, the return type, is overloaded, and only one type suffix is
4342required. Because the argument's type is matched against the return type, it
4343does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4344
4345<p>To learn how to add an intrinsic function, please see the
4346<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
4347</p>
4348
4349</div>
4350
4351<!-- ======================================================================= -->
4352<div class="doc_subsection">
4353 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4354</div>
4355
4356<div class="doc_text">
4357
4358<p>Variable argument support is defined in LLVM with the <a
4359 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4360intrinsic functions. These functions are related to the similarly
4361named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
4362
4363<p>All of these functions operate on arguments that use a
4364target-specific value type "<tt>va_list</tt>". The LLVM assembly
4365language reference manual does not define what this type is, so all
4366transformations should be prepared to handle these functions regardless of
4367the type used.</p>
4368
4369<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
4370instruction and the variable argument handling intrinsic functions are
4371used.</p>
4372
4373<div class="doc_code">
4374<pre>
4375define i32 @test(i32 %X, ...) {
4376 ; Initialize variable argument processing
4377 %ap = alloca i8*
4378 %ap2 = bitcast i8** %ap to i8*
4379 call void @llvm.va_start(i8* %ap2)
4380
4381 ; Read a single integer argument
4382 %tmp = va_arg i8** %ap, i32
4383
4384 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4385 %aq = alloca i8*
4386 %aq2 = bitcast i8** %aq to i8*
4387 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4388 call void @llvm.va_end(i8* %aq2)
4389
4390 ; Stop processing of arguments.
4391 call void @llvm.va_end(i8* %ap2)
4392 ret i32 %tmp
4393}
4394
4395declare void @llvm.va_start(i8*)
4396declare void @llvm.va_copy(i8*, i8*)
4397declare void @llvm.va_end(i8*)
4398</pre>
4399</div>
4400
4401</div>
4402
4403<!-- _______________________________________________________________________ -->
4404<div class="doc_subsubsection">
4405 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4406</div>
4407
4408
4409<div class="doc_text">
4410<h5>Syntax:</h5>
4411<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
4412<h5>Overview:</h5>
4413<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
4414<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4415href="#i_va_arg">va_arg</a></tt>.</p>
4416
4417<h5>Arguments:</h5>
4418
4419<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
4420
4421<h5>Semantics:</h5>
4422
4423<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
4424macro available in C. In a target-dependent way, it initializes the
4425<tt>va_list</tt> element to which the argument points, so that the next call to
4426<tt>va_arg</tt> will produce the first variable argument passed to the function.
4427Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
4428last argument of the function as the compiler can figure that out.</p>
4429
4430</div>
4431
4432<!-- _______________________________________________________________________ -->
4433<div class="doc_subsubsection">
4434 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
4435</div>
4436
4437<div class="doc_text">
4438<h5>Syntax:</h5>
4439<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
4440<h5>Overview:</h5>
4441
4442<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
4443which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
4444or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
4445
4446<h5>Arguments:</h5>
4447
4448<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
4449
4450<h5>Semantics:</h5>
4451
4452<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
4453macro available in C. In a target-dependent way, it destroys the
4454<tt>va_list</tt> element to which the argument points. Calls to <a
4455href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4456<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4457<tt>llvm.va_end</tt>.</p>
4458
4459</div>
4460
4461<!-- _______________________________________________________________________ -->
4462<div class="doc_subsubsection">
4463 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
4464</div>
4465
4466<div class="doc_text">
4467
4468<h5>Syntax:</h5>
4469
4470<pre>
4471 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
4472</pre>
4473
4474<h5>Overview:</h5>
4475
4476<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4477from the source argument list to the destination argument list.</p>
4478
4479<h5>Arguments:</h5>
4480
4481<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
4482The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
4483
4484
4485<h5>Semantics:</h5>
4486
4487<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4488macro available in C. In a target-dependent way, it copies the source
4489<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4490intrinsic is necessary because the <tt><a href="#int_va_start">
4491llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4492example, memory allocation.</p>
4493
4494</div>
4495
4496<!-- ======================================================================= -->
4497<div class="doc_subsection">
4498 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4499</div>
4500
4501<div class="doc_text">
4502
4503<p>
4504LLVM support for <a href="GarbageCollection.html">Accurate Garbage
4505Collection</a> requires the implementation and generation of these intrinsics.
4506These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
4507stack</a>, as well as garbage collector implementations that require <a
4508href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
4509Front-ends for type-safe garbage collected languages should generate these
4510intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4511href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4512</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]4513
4514<p>The garbage collection intrinsics only operate on objects in the generic
4515 address space (address space zero).</p>
4516
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4517</div>
4518
4519<!-- _______________________________________________________________________ -->
4520<div class="doc_subsubsection">
4521 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
4522</div>
4523
4524<div class="doc_text">
4525
4526<h5>Syntax:</h5>
4527
4528<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4529 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4530</pre>
4531
4532<h5>Overview:</h5>
4533
4534<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
4535the code generator, and allows some metadata to be associated with it.</p>
4536
4537<h5>Arguments:</h5>
4538
4539<p>The first argument specifies the address of a stack object that contains the
4540root pointer. The second pointer (which must be either a constant or a global
4541value address) contains the meta-data to be associated with the root.</p>
4542
4543<h5>Semantics:</h5>
4544
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]4545<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]4546location. At compile-time, the code generator generates information to allow
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4547the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4548intrinsic may only be used in a function which <a href="#gc">specifies a GC
4549algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4550
4551</div>
4552
4553
4554<!-- _______________________________________________________________________ -->
4555<div class="doc_subsubsection">
4556 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
4557</div>
4558
4559<div class="doc_text">
4560
4561<h5>Syntax:</h5>
4562
4563<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4564 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4565</pre>
4566
4567<h5>Overview:</h5>
4568
4569<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4570locations, allowing garbage collector implementations that require read
4571barriers.</p>
4572
4573<h5>Arguments:</h5>
4574
4575<p>The second argument is the address to read from, which should be an address
4576allocated from the garbage collector. The first object is a pointer to the
4577start of the referenced object, if needed by the language runtime (otherwise
4578null).</p>
4579
4580<h5>Semantics:</h5>
4581
4582<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4583instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4584garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4585may only be used in a function which <a href="#gc">specifies a GC
4586algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4587
4588</div>
4589
4590
4591<!-- _______________________________________________________________________ -->
4592<div class="doc_subsubsection">
4593 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
4594</div>
4595
4596<div class="doc_text">
4597
4598<h5>Syntax:</h5>
4599
4600<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4601 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4602</pre>
4603
4604<h5>Overview:</h5>
4605
4606<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4607locations, allowing garbage collector implementations that require write
4608barriers (such as generational or reference counting collectors).</p>
4609
4610<h5>Arguments:</h5>
4611
4612<p>The first argument is the reference to store, the second is the start of the
4613object to store it to, and the third is the address of the field of Obj to
4614store to. If the runtime does not require a pointer to the object, Obj may be
4615null.</p>
4616
4617<h5>Semantics:</h5>
4618
4619<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4620instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4621garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4622may only be used in a function which <a href="#gc">specifies a GC
4623algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4624
4625</div>
4626
4627
4628
4629<!-- ======================================================================= -->
4630<div class="doc_subsection">
4631 <a name="int_codegen">Code Generator Intrinsics</a>
4632</div>
4633
4634<div class="doc_text">
4635<p>
4636These intrinsics are provided by LLVM to expose special features that may only
4637be implemented with code generator support.
4638</p>
4639
4640</div>
4641
4642<!-- _______________________________________________________________________ -->
4643<div class="doc_subsubsection">
4644 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
4645</div>
4646
4647<div class="doc_text">
4648
4649<h5>Syntax:</h5>
4650<pre>
4651 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
4652</pre>
4653
4654<h5>Overview:</h5>
4655
4656<p>
4657The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4658target-specific value indicating the return address of the current function
4659or one of its callers.
4660</p>
4661
4662<h5>Arguments:</h5>
4663
4664<p>
4665The argument to this intrinsic indicates which function to return the address
4666for. Zero indicates the calling function, one indicates its caller, etc. The
4667argument is <b>required</b> to be a constant integer value.
4668</p>
4669
4670<h5>Semantics:</h5>
4671
4672<p>
4673The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4674the return address of the specified call frame, or zero if it cannot be
4675identified. The value returned by this intrinsic is likely to be incorrect or 0
4676for arguments other than zero, so it should only be used for debugging purposes.
4677</p>
4678
4679<p>
4680Note that calling this intrinsic does not prevent function inlining or other
4681aggressive transformations, so the value returned may not be that of the obvious
4682source-language caller.
4683</p>
4684</div>
4685
4686
4687<!-- _______________________________________________________________________ -->
4688<div class="doc_subsubsection">
4689 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
4690</div>
4691
4692<div class="doc_text">
4693
4694<h5>Syntax:</h5>
4695<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4696 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4697</pre>
4698
4699<h5>Overview:</h5>
4700
4701<p>
4702The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4703target-specific frame pointer value for the specified stack frame.
4704</p>
4705
4706<h5>Arguments:</h5>
4707
4708<p>
4709The argument to this intrinsic indicates which function to return the frame
4710pointer for. Zero indicates the calling function, one indicates its caller,
4711etc. The argument is <b>required</b> to be a constant integer value.
4712</p>
4713
4714<h5>Semantics:</h5>
4715
4716<p>
4717The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4718the frame address of the specified call frame, or zero if it cannot be
4719identified. The value returned by this intrinsic is likely to be incorrect or 0
4720for arguments other than zero, so it should only be used for debugging purposes.
4721</p>
4722
4723<p>
4724Note that calling this intrinsic does not prevent function inlining or other
4725aggressive transformations, so the value returned may not be that of the obvious
4726source-language caller.
4727</p>
4728</div>
4729
4730<!-- _______________________________________________________________________ -->
4731<div class="doc_subsubsection">
4732 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
4733</div>
4734
4735<div class="doc_text">
4736
4737<h5>Syntax:</h5>
4738<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4739 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4740</pre>
4741
4742<h5>Overview:</h5>
4743
4744<p>
4745The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
4746the function stack, for use with <a href="#int_stackrestore">
4747<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4748features like scoped automatic variable sized arrays in C99.
4749</p>
4750
4751<h5>Semantics:</h5>
4752
4753<p>
4754This intrinsic returns a opaque pointer value that can be passed to <a
4755href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
4756<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4757<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4758state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4759practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4760that were allocated after the <tt>llvm.stacksave</tt> was executed.
4761</p>
4762
4763</div>
4764
4765<!-- _______________________________________________________________________ -->
4766<div class="doc_subsubsection">
4767 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
4768</div>
4769
4770<div class="doc_text">
4771
4772<h5>Syntax:</h5>
4773<pre>
4774 declare void @llvm.stackrestore(i8 * %ptr)
4775</pre>
4776
4777<h5>Overview:</h5>
4778
4779<p>
4780The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4781the function stack to the state it was in when the corresponding <a
4782href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
4783useful for implementing language features like scoped automatic variable sized
4784arrays in C99.
4785</p>
4786
4787<h5>Semantics:</h5>
4788
4789<p>
4790See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
4791</p>
4792
4793</div>
4794
4795
4796<!-- _______________________________________________________________________ -->
4797<div class="doc_subsubsection">
4798 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
4799</div>
4800
4801<div class="doc_text">
4802
4803<h5>Syntax:</h5>
4804<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4805 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]4806</pre>
4807
4808<h5>Overview:</h5>
4809
4810
4811<p>
4812The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
4813a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4814no
4815effect on the behavior of the program but can change its performance
4816characteristics.
4817</p>
4818
4819<h5>Arguments:</h5>
4820
4821<p>
4822<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4823determining if the fetch should be for a read (0) or write (1), and
4824<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
4825locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
4826<tt>locality</tt> arguments must be constant integers.
4827</p>
4828
4829<h5>Semantics:</h5>
4830
4831<p>
4832This intrinsic does not modify the behavior of the program. In particular,
4833prefetches cannot trap and do not produce a value. On targets that support this
4834intrinsic, the prefetch can provide hints to the processor cache for better
4835performance.
4836</p>
4837
4838</div>
4839
4840<!-- _______________________________________________________________________ -->
4841<div class="doc_subsubsection">
4842 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
4843</div>
4844
4845<div class="doc_text">
4846
4847<h5>Syntax:</h5>
4848<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4849 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4850</pre>
4851
4852<h5>Overview:</h5>
4853
4854
4855<p>
4856The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4857(PC) in a region of
4858code to simulators and other tools. The method is target specific, but it is
4859expected that the marker will use exported symbols to transmit the PC of the marker.
4860The marker makes no guarantees that it will remain with any specific instruction
4861after optimizations. It is possible that the presence of a marker will inhibit
4862optimizations. The intended use is to be inserted after optimizations to allow
4863correlations of simulation runs.
4864</p>
4865
4866<h5>Arguments:</h5>
4867
4868<p>
4869<tt>id</tt> is a numerical id identifying the marker.
4870</p>
4871
4872<h5>Semantics:</h5>
4873
4874<p>
4875This intrinsic does not modify the behavior of the program. Backends that do not
4876support this intrinisic may ignore it.
4877</p>
4878
4879</div>
4880
4881<!-- _______________________________________________________________________ -->
4882<div class="doc_subsubsection">
4883 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
4884</div>
4885
4886<div class="doc_text">
4887
4888<h5>Syntax:</h5>
4889<pre>
4890 declare i64 @llvm.readcyclecounter( )
4891</pre>
4892
4893<h5>Overview:</h5>
4894
4895
4896<p>
4897The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4898counter register (or similar low latency, high accuracy clocks) on those targets
4899that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4900As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4901should only be used for small timings.
4902</p>
4903
4904<h5>Semantics:</h5>
4905
4906<p>
4907When directly supported, reading the cycle counter should not modify any memory.
4908Implementations are allowed to either return a application specific value or a
4909system wide value. On backends without support, this is lowered to a constant 0.
4910</p>
4911
4912</div>
4913
4914<!-- ======================================================================= -->
4915<div class="doc_subsection">
4916 <a name="int_libc">Standard C Library Intrinsics</a>
4917</div>
4918
4919<div class="doc_text">
4920<p>
4921LLVM provides intrinsics for a few important standard C library functions.
4922These intrinsics allow source-language front-ends to pass information about the
4923alignment of the pointer arguments to the code generator, providing opportunity
4924for more efficient code generation.
4925</p>
4926
4927</div>
4928
4929<!-- _______________________________________________________________________ -->
4930<div class="doc_subsubsection">
4931 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
4932</div>
4933
4934<div class="doc_text">
4935
4936<h5>Syntax:</h5>
4937<pre>
4938 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4939 i32 &lt;len&gt;, i32 &lt;align&gt;)
4940 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4941 i64 &lt;len&gt;, i32 &lt;align&gt;)
4942</pre>
4943
4944<h5>Overview:</h5>
4945
4946<p>
4947The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
4948location to the destination location.
4949</p>
4950
4951<p>
4952Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4953intrinsics do not return a value, and takes an extra alignment argument.
4954</p>
4955
4956<h5>Arguments:</h5>
4957
4958<p>
4959The first argument is a pointer to the destination, the second is a pointer to
4960the source. The third argument is an integer argument
4961specifying the number of bytes to copy, and the fourth argument is the alignment
4962of the source and destination locations.
4963</p>
4964
4965<p>
4966If the call to this intrinisic has an alignment value that is not 0 or 1, then
4967the caller guarantees that both the source and destination pointers are aligned
4968to that boundary.
4969</p>
4970
4971<h5>Semantics:</h5>
4972
4973<p>
4974The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
4975location to the destination location, which are not allowed to overlap. It
4976copies "len" bytes of memory over. If the argument is known to be aligned to
4977some boundary, this can be specified as the fourth argument, otherwise it should
4978be set to 0 or 1.
4979</p>
4980</div>
4981
4982
4983<!-- _______________________________________________________________________ -->
4984<div class="doc_subsubsection">
4985 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
4986</div>
4987
4988<div class="doc_text">
4989
4990<h5>Syntax:</h5>
4991<pre>
4992 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4993 i32 &lt;len&gt;, i32 &lt;align&gt;)
4994 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4995 i64 &lt;len&gt;, i32 &lt;align&gt;)
4996</pre>
4997
4998<h5>Overview:</h5>
4999
5000<p>
5001The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5002location to the destination location. It is similar to the
Chris Lattnerdba16ea2008-01-06 19:51:52 +0000[diff] [blame]5003'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5004</p>
5005
5006<p>
5007Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5008intrinsics do not return a value, and takes an extra alignment argument.
5009</p>
5010
5011<h5>Arguments:</h5>
5012
5013<p>
5014The first argument is a pointer to the destination, the second is a pointer to
5015the source. The third argument is an integer argument
5016specifying the number of bytes to copy, and the fourth argument is the alignment
5017of the source and destination locations.
5018</p>
5019
5020<p>
5021If the call to this intrinisic has an alignment value that is not 0 or 1, then
5022the caller guarantees that the source and destination pointers are aligned to
5023that boundary.
5024</p>
5025
5026<h5>Semantics:</h5>
5027
5028<p>
5029The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
5030location to the destination location, which may overlap. It
5031copies "len" bytes of memory over. If the argument is known to be aligned to
5032some boundary, this can be specified as the fourth argument, otherwise it should
5033be set to 0 or 1.
5034</p>
5035</div>
5036
5037
5038<!-- _______________________________________________________________________ -->
5039<div class="doc_subsubsection">
5040 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5041</div>
5042
5043<div class="doc_text">
5044
5045<h5>Syntax:</h5>
5046<pre>
5047 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5048 i32 &lt;len&gt;, i32 &lt;align&gt;)
5049 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5050 i64 &lt;len&gt;, i32 &lt;align&gt;)
5051</pre>
5052
5053<h5>Overview:</h5>
5054
5055<p>
5056The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
5057byte value.
5058</p>
5059
5060<p>
5061Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5062does not return a value, and takes an extra alignment argument.
5063</p>
5064
5065<h5>Arguments:</h5>
5066
5067<p>
5068The first argument is a pointer to the destination to fill, the second is the
5069byte value to fill it with, the third argument is an integer
5070argument specifying the number of bytes to fill, and the fourth argument is the
5071known alignment of destination location.
5072</p>
5073
5074<p>
5075If the call to this intrinisic has an alignment value that is not 0 or 1, then
5076the caller guarantees that the destination pointer is aligned to that boundary.
5077</p>
5078
5079<h5>Semantics:</h5>
5080
5081<p>
5082The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5083the
5084destination location. If the argument is known to be aligned to some boundary,
5085this can be specified as the fourth argument, otherwise it should be set to 0 or
50861.
5087</p>
5088</div>
5089
5090
5091<!-- _______________________________________________________________________ -->
5092<div class="doc_subsubsection">
5093 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5094</div>
5095
5096<div class="doc_text">
5097
5098<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5099<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]5100floating point or vector of floating point type. Not all targets support all
5101types however.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5102<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5103 declare float @llvm.sqrt.f32(float %Val)
5104 declare double @llvm.sqrt.f64(double %Val)
5105 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5106 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5107 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5108</pre>
5109
5110<h5>Overview:</h5>
5111
5112<p>
5113The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5114returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5115<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattnerf914a002008-01-29 07:00:44 +0000[diff] [blame]5116negative numbers other than -0.0 (which allows for better optimization, because
5117there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5118defined to return -0.0 like IEEE sqrt.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5119</p>
5120
5121<h5>Arguments:</h5>
5122
5123<p>
5124The argument and return value are floating point numbers of the same type.
5125</p>
5126
5127<h5>Semantics:</h5>
5128
5129<p>
5130This function returns the sqrt of the specified operand if it is a nonnegative
5131floating point number.
5132</p>
5133</div>
5134
5135<!-- _______________________________________________________________________ -->
5136<div class="doc_subsubsection">
5137 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5138</div>
5139
5140<div class="doc_text">
5141
5142<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5143<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]5144floating point or vector of floating point type. Not all targets support all
5145types however.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5146<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5147 declare float @llvm.powi.f32(float %Val, i32 %power)
5148 declare double @llvm.powi.f64(double %Val, i32 %power)
5149 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5150 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5151 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5152</pre>
5153
5154<h5>Overview:</h5>
5155
5156<p>
5157The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5158specified (positive or negative) power. The order of evaluation of
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5159multiplications is not defined. When a vector of floating point type is
5160used, the second argument remains a scalar integer value.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5161</p>
5162
5163<h5>Arguments:</h5>
5164
5165<p>
5166The second argument is an integer power, and the first is a value to raise to
5167that power.
5168</p>
5169
5170<h5>Semantics:</h5>
5171
5172<p>
5173This function returns the first value raised to the second power with an
5174unspecified sequence of rounding operations.</p>
5175</div>
5176
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5177<!-- _______________________________________________________________________ -->
5178<div class="doc_subsubsection">
5179 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5180</div>
5181
5182<div class="doc_text">
5183
5184<h5>Syntax:</h5>
5185<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5186floating point or vector of floating point type. Not all targets support all
5187types however.
5188<pre>
5189 declare float @llvm.sin.f32(float %Val)
5190 declare double @llvm.sin.f64(double %Val)
5191 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5192 declare fp128 @llvm.sin.f128(fp128 %Val)
5193 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5194</pre>
5195
5196<h5>Overview:</h5>
5197
5198<p>
5199The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5200</p>
5201
5202<h5>Arguments:</h5>
5203
5204<p>
5205The argument and return value are floating point numbers of the same type.
5206</p>
5207
5208<h5>Semantics:</h5>
5209
5210<p>
5211This function returns the sine of the specified operand, returning the
5212same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5213conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5214</div>
5215
5216<!-- _______________________________________________________________________ -->
5217<div class="doc_subsubsection">
5218 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5219</div>
5220
5221<div class="doc_text">
5222
5223<h5>Syntax:</h5>
5224<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5225floating point or vector of floating point type. Not all targets support all
5226types however.
5227<pre>
5228 declare float @llvm.cos.f32(float %Val)
5229 declare double @llvm.cos.f64(double %Val)
5230 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5231 declare fp128 @llvm.cos.f128(fp128 %Val)
5232 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5233</pre>
5234
5235<h5>Overview:</h5>
5236
5237<p>
5238The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5239</p>
5240
5241<h5>Arguments:</h5>
5242
5243<p>
5244The argument and return value are floating point numbers of the same type.
5245</p>
5246
5247<h5>Semantics:</h5>
5248
5249<p>
5250This function returns the cosine of the specified operand, returning the
5251same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5252conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5253</div>
5254
5255<!-- _______________________________________________________________________ -->
5256<div class="doc_subsubsection">
5257 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5258</div>
5259
5260<div class="doc_text">
5261
5262<h5>Syntax:</h5>
5263<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5264floating point or vector of floating point type. Not all targets support all
5265types however.
5266<pre>
5267 declare float @llvm.pow.f32(float %Val, float %Power)
5268 declare double @llvm.pow.f64(double %Val, double %Power)
5269 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5270 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5271 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5272</pre>
5273
5274<h5>Overview:</h5>
5275
5276<p>
5277The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5278specified (positive or negative) power.
5279</p>
5280
5281<h5>Arguments:</h5>
5282
5283<p>
5284The second argument is a floating point power, and the first is a value to
5285raise to that power.
5286</p>
5287
5288<h5>Semantics:</h5>
5289
5290<p>
5291This function returns the first value raised to the second power,
5292returning the
5293same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5294conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5295</div>
5296
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5297
5298<!-- ======================================================================= -->
5299<div class="doc_subsection">
5300 <a name="int_manip">Bit Manipulation Intrinsics</a>
5301</div>
5302
5303<div class="doc_text">
5304<p>
5305LLVM provides intrinsics for a few important bit manipulation operations.
5306These allow efficient code generation for some algorithms.
5307</p>
5308
5309</div>
5310
5311<!-- _______________________________________________________________________ -->
5312<div class="doc_subsubsection">
5313 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5314</div>
5315
5316<div class="doc_text">
5317
5318<h5>Syntax:</h5>
5319<p>This is an overloaded intrinsic function. You can use bswap on any integer
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5320type that is an even number of bytes (i.e. BitWidth % 16 == 0).
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5321<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5322 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5323 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5324 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5325</pre>
5326
5327<h5>Overview:</h5>
5328
5329<p>
5330The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5331values with an even number of bytes (positive multiple of 16 bits). These are
5332useful for performing operations on data that is not in the target's native
5333byte order.
5334</p>
5335
5336<h5>Semantics:</h5>
5337
5338<p>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5339The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5340and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5341intrinsic returns an i32 value that has the four bytes of the input i32
5342swapped, 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]5343i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5344<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5345additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
5346</p>
5347
5348</div>
5349
5350<!-- _______________________________________________________________________ -->
5351<div class="doc_subsubsection">
5352 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5353</div>
5354
5355<div class="doc_text">
5356
5357<h5>Syntax:</h5>
5358<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
5359width. Not all targets support all bit widths however.
5360<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5361 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
5362 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5363 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5364 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5365 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5366</pre>
5367
5368<h5>Overview:</h5>
5369
5370<p>
5371The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5372value.
5373</p>
5374
5375<h5>Arguments:</h5>
5376
5377<p>
5378The only argument is the value to be counted. The argument may be of any
5379integer type. The return type must match the argument type.
5380</p>
5381
5382<h5>Semantics:</h5>
5383
5384<p>
5385The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5386</p>
5387</div>
5388
5389<!-- _______________________________________________________________________ -->
5390<div class="doc_subsubsection">
5391 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5392</div>
5393
5394<div class="doc_text">
5395
5396<h5>Syntax:</h5>
5397<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
5398integer bit width. Not all targets support all bit widths however.
5399<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5400 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5401 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5402 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5403 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5404 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5405</pre>
5406
5407<h5>Overview:</h5>
5408
5409<p>
5410The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5411leading zeros in a variable.
5412</p>
5413
5414<h5>Arguments:</h5>
5415
5416<p>
5417The only argument is the value to be counted. The argument may be of any
5418integer type. The return type must match the argument type.
5419</p>
5420
5421<h5>Semantics:</h5>
5422
5423<p>
5424The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5425in a variable. If the src == 0 then the result is the size in bits of the type
5426of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
5427</p>
5428</div>
5429
5430
5431
5432<!-- _______________________________________________________________________ -->
5433<div class="doc_subsubsection">
5434 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5435</div>
5436
5437<div class="doc_text">
5438
5439<h5>Syntax:</h5>
5440<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
5441integer bit width. Not all targets support all bit widths however.
5442<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5443 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5444 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5445 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5446 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5447 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5448</pre>
5449
5450<h5>Overview:</h5>
5451
5452<p>
5453The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5454trailing zeros.
5455</p>
5456
5457<h5>Arguments:</h5>
5458
5459<p>
5460The only argument is the value to be counted. The argument may be of any
5461integer type. The return type must match the argument type.
5462</p>
5463
5464<h5>Semantics:</h5>
5465
5466<p>
5467The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5468in a variable. If the src == 0 then the result is the size in bits of the type
5469of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5470</p>
5471</div>
5472
5473<!-- _______________________________________________________________________ -->
5474<div class="doc_subsubsection">
5475 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
5476</div>
5477
5478<div class="doc_text">
5479
5480<h5>Syntax:</h5>
5481<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
5482on any integer bit width.
5483<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5484 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5485 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5486</pre>
5487
5488<h5>Overview:</h5>
5489<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
5490range of bits from an integer value and returns them in the same bit width as
5491the original value.</p>
5492
5493<h5>Arguments:</h5>
5494<p>The first argument, <tt>%val</tt> and the result may be integer types of
5495any bit width but they must have the same bit width. The second and third
5496arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
5497
5498<h5>Semantics:</h5>
5499<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
5500of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5501<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5502operates in forward mode.</p>
5503<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5504right by <tt>%loBit</tt> bits and then ANDing it with a mask with
5505only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5506<ol>
5507 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5508 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5509 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5510 to determine the number of bits to retain.</li>
5511 <li>A mask of the retained bits is created by shifting a -1 value.</li>
5512 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
5513</ol>
5514<p>In reverse mode, a similar computation is made except that the bits are
5515returned in the reverse order. So, for example, if <tt>X</tt> has the value
5516<tt>i16 0x0ACF (101011001111)</tt> and we apply
5517<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5518<tt>i16 0x0026 (000000100110)</tt>.</p>
5519</div>
5520
5521<div class="doc_subsubsection">
5522 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5523</div>
5524
5525<div class="doc_text">
5526
5527<h5>Syntax:</h5>
5528<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
5529on any integer bit width.
5530<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5531 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5532 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]5533</pre>
5534
5535<h5>Overview:</h5>
5536<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5537of bits in an integer value with another integer value. It returns the integer
5538with the replaced bits.</p>
5539
5540<h5>Arguments:</h5>
5541<p>The first argument, <tt>%val</tt> and the result may be integer types of
5542any bit width but they must have the same bit width. <tt>%val</tt> is the value
5543whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5544integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5545type since they specify only a bit index.</p>
5546
5547<h5>Semantics:</h5>
5548<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5549of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5550<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5551operates in forward mode.</p>
5552<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5553truncating it down to the size of the replacement area or zero extending it
5554up to that size.</p>
5555<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5556are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5557in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
5558to the <tt>%hi</tt>th bit.
5559<p>In reverse mode, a similar computation is made except that the bits are
5560reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
5561<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.
5562<h5>Examples:</h5>
5563<pre>
5564 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
5565 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5566 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5567 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
5568 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
5569</pre>
5570</div>
5571
5572<!-- ======================================================================= -->
5573<div class="doc_subsection">
5574 <a name="int_debugger">Debugger Intrinsics</a>
5575</div>
5576
5577<div class="doc_text">
5578<p>
5579The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5580are described in the <a
5581href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5582Debugging</a> document.
5583</p>
5584</div>
5585
5586
5587<!-- ======================================================================= -->
5588<div class="doc_subsection">
5589 <a name="int_eh">Exception Handling Intrinsics</a>
5590</div>
5591
5592<div class="doc_text">
5593<p> The LLVM exception handling intrinsics (which all start with
5594<tt>llvm.eh.</tt> prefix), are described in the <a
5595href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5596Handling</a> document. </p>
5597</div>
5598
5599<!-- ======================================================================= -->
5600<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5601 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5602</div>
5603
5604<div class="doc_text">
5605<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5606 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5607 the <tt>nest</tt> attribute, from a function. The result is a callable
5608 function pointer lacking the nest parameter - the caller does not need
5609 to provide a value for it. Instead, the value to use is stored in
5610 advance in a "trampoline", a block of memory usually allocated
5611 on the stack, which also contains code to splice the nest value into the
5612 argument list. This is used to implement the GCC nested function address
5613 extension.
5614</p>
5615<p>
5616 For example, if the function is
5617 <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]5618 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]5619<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5620 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5621 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5622 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5623 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5624</pre>
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]5625 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5626 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5627</div>
5628
5629<!-- _______________________________________________________________________ -->
5630<div class="doc_subsubsection">
5631 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5632</div>
5633<div class="doc_text">
5634<h5>Syntax:</h5>
5635<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5636declare 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]5637</pre>
5638<h5>Overview:</h5>
5639<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5640 This fills the memory pointed to by <tt>tramp</tt> with code
5641 and returns a function pointer suitable for executing it.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5642</p>
5643<h5>Arguments:</h5>
5644<p>
5645 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5646 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5647 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sands35012212007-08-22 23:39:54 +0000[diff] [blame]5648 intrinsic. Note that the size and the alignment are target-specific - LLVM
5649 currently provides no portable way of determining them, so a front-end that
5650 generates this intrinsic needs to have some target-specific knowledge.
5651 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]5652</p>
5653<h5>Semantics:</h5>
5654<p>
5655 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5656 dependent code, turning it into a function. A pointer to this function is
5657 returned, but needs to be bitcast to an
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5658 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5659 before being called. The new function's signature is the same as that of
5660 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5661 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5662 of pointer type. Calling the new function is equivalent to calling
5663 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5664 missing <tt>nest</tt> argument. If, after calling
5665 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5666 modified, then the effect of any later call to the returned function pointer is
5667 undefined.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5668</p>
5669</div>
5670
5671<!-- ======================================================================= -->
5672<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5673 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
5674</div>
5675
5676<div class="doc_text">
5677<p>
5678 These intrinsic functions expand the "universal IR" of LLVM to represent
5679 hardware constructs for atomic operations and memory synchronization. This
5680 provides an interface to the hardware, not an interface to the programmer. It
5681 is aimed at a low enough level to allow any programming models or APIs which
5682 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
5683 hardware behavior. Just as hardware provides a "universal IR" for source
5684 languages, it also provides a starting point for developing a "universal"
5685 atomic operation and synchronization IR.
5686</p>
5687<p>
5688 These do <em>not</em> form an API such as high-level threading libraries,
5689 software transaction memory systems, atomic primitives, and intrinsic
5690 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
5691 application libraries. The hardware interface provided by LLVM should allow
5692 a clean implementation of all of these APIs and parallel programming models.
5693 No one model or paradigm should be selected above others unless the hardware
5694 itself ubiquitously does so.
5695
5696</p>
5697</div>
5698
5699<!-- _______________________________________________________________________ -->
5700<div class="doc_subsubsection">
5701 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5702</div>
5703<div class="doc_text">
5704<h5>Syntax:</h5>
5705<pre>
5706declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
5707i1 &lt;device&gt; )
5708
5709</pre>
5710<h5>Overview:</h5>
5711<p>
5712 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5713 specific pairs of memory access types.
5714</p>
5715<h5>Arguments:</h5>
5716<p>
5717 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
5718 The first four arguments enables a specific barrier as listed below. The fith
5719 argument specifies that the barrier applies to io or device or uncached memory.
5720
5721</p>
5722 <ul>
5723 <li><tt>ll</tt>: load-load barrier</li>
5724 <li><tt>ls</tt>: load-store barrier</li>
5725 <li><tt>sl</tt>: store-load barrier</li>
5726 <li><tt>ss</tt>: store-store barrier</li>
5727 <li><tt>device</tt>: barrier applies to device and uncached memory also.
5728 </ul>
5729<h5>Semantics:</h5>
5730<p>
5731 This intrinsic causes the system to enforce some ordering constraints upon
5732 the loads and stores of the program. This barrier does not indicate
5733 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5734 which they occur. For any of the specified pairs of load and store operations
5735 (f.ex. load-load, or store-load), all of the first operations preceding the
5736 barrier will complete before any of the second operations succeeding the
5737 barrier begin. Specifically the semantics for each pairing is as follows:
5738</p>
5739 <ul>
5740 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5741 after the barrier begins.</li>
5742
5743 <li><tt>ls</tt>: All loads before the barrier must complete before any
5744 store after the barrier begins.</li>
5745 <li><tt>ss</tt>: All stores before the barrier must complete before any
5746 store after the barrier begins.</li>
5747 <li><tt>sl</tt>: All stores before the barrier must complete before any
5748 load after the barrier begins.</li>
5749 </ul>
5750<p>
5751 These semantics are applied with a logical "and" behavior when more than one
5752 is enabled in a single memory barrier intrinsic.
5753</p>
5754<p>
5755 Backends may implement stronger barriers than those requested when they do not
5756 support as fine grained a barrier as requested. Some architectures do not
5757 need all types of barriers and on such architectures, these become noops.
5758</p>
5759<h5>Example:</h5>
5760<pre>
5761%ptr = malloc i32
5762 store i32 4, %ptr
5763
5764%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
5765 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
5766 <i>; guarantee the above finishes</i>
5767 store i32 8, %ptr <i>; before this begins</i>
5768</pre>
5769</div>
5770
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5771<!-- _______________________________________________________________________ -->
5772<div class="doc_subsubsection">
5773 <a name="int_atomic_lcs">'<tt>llvm.atomic.lcs.*</tt>' Intrinsic</a>
5774</div>
5775<div class="doc_text">
5776<h5>Syntax:</h5>
5777<p>
5778 This is an overloaded intrinsic. You can use <tt>llvm.atomic.lcs</tt> on any
5779 integer bit width. Not all targets support all bit widths however.</p>
5780
5781<pre>
5782declare i8 @llvm.atomic.lcs.i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
5783declare i16 @llvm.atomic.lcs.i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
5784declare i32 @llvm.atomic.lcs.i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
5785declare i64 @llvm.atomic.lcs.i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
5786
5787</pre>
5788<h5>Overview:</h5>
5789<p>
5790 This loads a value in memory and compares it to a given value. If they are
5791 equal, it stores a new value into the memory.
5792</p>
5793<h5>Arguments:</h5>
5794<p>
5795 The <tt>llvm.atomic.lcs</tt> intrinsic takes three arguments. The result as
5796 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
5797 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
5798 this integer type. While any bit width integer may be used, targets may only
5799 lower representations they support in hardware.
5800
5801</p>
5802<h5>Semantics:</h5>
5803<p>
5804 This entire intrinsic must be executed atomically. It first loads the value
5805 in memory pointed to by <tt>ptr</tt> and compares it with the value
5806 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
5807 loaded value is yielded in all cases. This provides the equivalent of an
5808 atomic compare-and-swap operation within the SSA framework.
5809</p>
5810<h5>Examples:</h5>
5811
5812<pre>
5813%ptr = malloc i32
5814 store i32 4, %ptr
5815
5816%val1 = add i32 4, 4
5817%result1 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 4, %val1 )
5818 <i>; yields {i32}:result1 = 4</i>
5819%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5820%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5821
5822%val2 = add i32 1, 1
5823%result2 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 5, %val2 )
5824 <i>; yields {i32}:result2 = 8</i>
5825%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
5826
5827%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
5828</pre>
5829</div>
5830
5831<!-- _______________________________________________________________________ -->
5832<div class="doc_subsubsection">
5833 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
5834</div>
5835<div class="doc_text">
5836<h5>Syntax:</h5>
5837
5838<p>
5839 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
5840 integer bit width. Not all targets support all bit widths however.</p>
5841<pre>
5842declare i8 @llvm.atomic.swap.i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
5843declare i16 @llvm.atomic.swap.i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
5844declare i32 @llvm.atomic.swap.i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
5845declare i64 @llvm.atomic.swap.i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
5846
5847</pre>
5848<h5>Overview:</h5>
5849<p>
5850 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
5851 the value from memory. It then stores the value in <tt>val</tt> in the memory
5852 at <tt>ptr</tt>.
5853</p>
5854<h5>Arguments:</h5>
5855
5856<p>
5857 The <tt>llvm.atomic.ls</tt> intrinsic takes two arguments. Both the
5858 <tt>val</tt> argument and the result must be integers of the same bit width.
5859 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
5860 integer type. The targets may only lower integer representations they
5861 support.
5862</p>
5863<h5>Semantics:</h5>
5864<p>
5865 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
5866 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
5867 equivalent of an atomic swap operation within the SSA framework.
5868
5869</p>
5870<h5>Examples:</h5>
5871<pre>
5872%ptr = malloc i32
5873 store i32 4, %ptr
5874
5875%val1 = add i32 4, 4
5876%result1 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val1 )
5877 <i>; yields {i32}:result1 = 4</i>
5878%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5879%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5880
5881%val2 = add i32 1, 1
5882%result2 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val2 )
5883 <i>; yields {i32}:result2 = 8</i>
5884
5885%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
5886%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
5887</pre>
5888</div>
5889
5890<!-- _______________________________________________________________________ -->
5891<div class="doc_subsubsection">
5892 <a name="int_atomic_las">'<tt>llvm.atomic.las.*</tt>' Intrinsic</a>
5893
5894</div>
5895<div class="doc_text">
5896<h5>Syntax:</h5>
5897<p>
5898 This is an overloaded intrinsic. You can use <tt>llvm.atomic.las</tt> on any
5899 integer bit width. Not all targets support all bit widths however.</p>
5900<pre>
5901declare i8 @llvm.atomic.las.i8.( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
5902declare i16 @llvm.atomic.las.i16.( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
5903declare i32 @llvm.atomic.las.i32.( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
5904declare i64 @llvm.atomic.las.i64.( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
5905
5906</pre>
5907<h5>Overview:</h5>
5908<p>
5909 This intrinsic adds <tt>delta</tt> to the value stored in memory at
5910 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
5911</p>
5912<h5>Arguments:</h5>
5913<p>
5914
5915 The intrinsic takes two arguments, the first a pointer to an integer value
5916 and the second an integer value. The result is also an integer value. These
5917 integer types can have any bit width, but they must all have the same bit
5918 width. The targets may only lower integer representations they support.
5919</p>
5920<h5>Semantics:</h5>
5921<p>
5922 This intrinsic does a series of operations atomically. It first loads the
5923 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
5924 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
5925</p>
5926
5927<h5>Examples:</h5>
5928<pre>
5929%ptr = malloc i32
5930 store i32 4, %ptr
5931%result1 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 4 )
5932 <i>; yields {i32}:result1 = 4</i>
5933%result2 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 2 )
5934 <i>; yields {i32}:result2 = 8</i>
5935%result3 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 5 )
5936 <i>; yields {i32}:result3 = 10</i>
5937%memval = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
5938</pre>
5939</div>
5940
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5941
5942<!-- ======================================================================= -->
5943<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5944 <a name="int_general">General Intrinsics</a>
5945</div>
5946
5947<div class="doc_text">
5948<p> This class of intrinsics is designed to be generic and has
5949no specific purpose. </p>
5950</div>
5951
5952<!-- _______________________________________________________________________ -->
5953<div class="doc_subsubsection">
5954 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
5955</div>
5956
5957<div class="doc_text">
5958
5959<h5>Syntax:</h5>
5960<pre>
5961 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5962</pre>
5963
5964<h5>Overview:</h5>
5965
5966<p>
5967The '<tt>llvm.var.annotation</tt>' intrinsic
5968</p>
5969
5970<h5>Arguments:</h5>
5971
5972<p>
5973The first argument is a pointer to a value, the second is a pointer to a
5974global string, the third is a pointer to a global string which is the source
5975file name, and the last argument is the line number.
5976</p>
5977
5978<h5>Semantics:</h5>
5979
5980<p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]5981This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5982This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]5983annotations. These have no other defined use, they are ignored by code
5984generation and optimization.
5985</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5986</div>
5987
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]5988<!-- _______________________________________________________________________ -->
5989<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]5990 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]5991</div>
5992
5993<div class="doc_text">
5994
5995<h5>Syntax:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]5996<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
5997any integer bit width.
5998</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]5999<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]6000 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6001 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6002 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6003 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6004 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]6005</pre>
6006
6007<h5>Overview:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6008
6009<p>
6010The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6011</p>
6012
6013<h5>Arguments:</h5>
6014
6015<p>
6016The first argument is an integer value (result of some expression),
6017the second is a pointer to a global string, the third is a pointer to a global
6018string which is the source file name, and the last argument is the line number.
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6019It returns the value of the first argument.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6020</p>
6021
6022<h5>Semantics:</h5>
6023
6024<p>
6025This intrinsic allows annotations to be put on arbitrary expressions
6026with arbitrary strings. This can be useful for special purpose optimizations
6027that want to look for these annotations. These have no other defined use, they
6028are ignored by code generation and optimization.
6029</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6030
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6031<!-- _______________________________________________________________________ -->
6032<div class="doc_subsubsection">
6033 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6034</div>
6035
6036<div class="doc_text">
6037
6038<h5>Syntax:</h5>
6039<pre>
6040 declare void @llvm.trap()
6041</pre>
6042
6043<h5>Overview:</h5>
6044
6045<p>
6046The '<tt>llvm.trap</tt>' intrinsic
6047</p>
6048
6049<h5>Arguments:</h5>
6050
6051<p>
6052None
6053</p>
6054
6055<h5>Semantics:</h5>
6056
6057<p>
6058This intrinsics is lowered to the target dependent trap instruction. If the
6059target does not have a trap instruction, this intrinsic will be lowered to the
6060call of the abort() function.
6061</p>
6062</div>
6063
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6064<!-- *********************************************************************** -->
6065<hr>
6066<address>
6067 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
6068 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
6069 <a href="http://validator.w3.org/check/referer"><img
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]6070 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6071
6072 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
6073 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
6074 Last modified: $Date$
6075</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]6076
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6077</body>
6078</html>