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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 44676cf84be8f7ba48233dd88ae9e4c977431510 / . / docs / LangRef.html
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5 <title>LLVM Assembly Language Reference Manual</title>
6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
12
13<body>
14
15<div class="doc_title"> LLVM Language Reference Manual </div>
16<ol>
17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
23 <li><a href="#linkage">Linkage Types</a></li>
24 <li><a href="#callingconv">Calling Conventions</a></li>
25 <li><a href="#globalvars">Global Variables</a></li>
26 <li><a href="#functionstructure">Functions</a></li>
27 <li><a href="#aliasstructure">Aliases</a>
28 <li><a href="#paramattrs">Parameter Attributes</a></li>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]29 <li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]30 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
31 <li><a href="#datalayout">Data Layout</a></li>
32 </ol>
33 </li>
34 <li><a href="#typesystem">Type System</a>
35 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]36 <li><a href="#t_classifications">Type Classifications</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]37 <li><a href="#t_primitive">Primitive Types</a>
38 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]39 <li><a href="#t_floating">Floating Point Types</a></li>
40 <li><a href="#t_void">Void Type</a></li>
41 <li><a href="#t_label">Label Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]42 </ol>
43 </li>
44 <li><a href="#t_derived">Derived Types</a>
45 <ol>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]46 <li><a href="#t_integer">Integer Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]47 <li><a href="#t_array">Array Type</a></li>
48 <li><a href="#t_function">Function Type</a></li>
49 <li><a href="#t_pointer">Pointer Type</a></li>
50 <li><a href="#t_struct">Structure Type</a></li>
51 <li><a href="#t_pstruct">Packed Structure Type</a></li>
52 <li><a href="#t_vector">Vector Type</a></li>
53 <li><a href="#t_opaque">Opaque Type</a></li>
54 </ol>
55 </li>
56 </ol>
57 </li>
58 <li><a href="#constants">Constants</a>
59 <ol>
60 <li><a href="#simpleconstants">Simple Constants</a>
61 <li><a href="#aggregateconstants">Aggregate Constants</a>
62 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
63 <li><a href="#undefvalues">Undefined Values</a>
64 <li><a href="#constantexprs">Constant Expressions</a>
65 </ol>
66 </li>
67 <li><a href="#othervalues">Other Values</a>
68 <ol>
69 <li><a href="#inlineasm">Inline Assembler Expressions</a>
70 </ol>
71 </li>
72 <li><a href="#instref">Instruction Reference</a>
73 <ol>
74 <li><a href="#terminators">Terminator Instructions</a>
75 <ol>
76 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
77 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
78 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
79 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
80 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
81 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
82 </ol>
83 </li>
84 <li><a href="#binaryops">Binary Operations</a>
85 <ol>
86 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
87 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
88 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
89 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
90 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
91 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
92 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
93 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
94 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
95 </ol>
96 </li>
97 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
98 <ol>
99 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
100 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
101 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
102 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
103 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
104 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
105 </ol>
106 </li>
107 <li><a href="#vectorops">Vector Operations</a>
108 <ol>
109 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
110 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
111 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
112 </ol>
113 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]114 <li><a href="#aggregateops">Aggregate Operations</a>
115 <ol>
116 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
117 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
118 </ol>
119 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]120 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
121 <ol>
122 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
123 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
124 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
125 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
126 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
127 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
128 </ol>
129 </li>
130 <li><a href="#convertops">Conversion Operations</a>
131 <ol>
132 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
133 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
134 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
135 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
136 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
137 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
138 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
139 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
140 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
141 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
142 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
143 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
144 </ol>
145 <li><a href="#otherops">Other Operations</a>
146 <ol>
147 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
148 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]149 <li><a href="#i_vicmp">'<tt>vicmp</tt>' Instruction</a></li>
150 <li><a href="#i_vfcmp">'<tt>vfcmp</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]151 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
152 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
153 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
154 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]155 <li><a href="#i_getresult">'<tt>getresult</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]156 </ol>
157 </li>
158 </ol>
159 </li>
160 <li><a href="#intrinsics">Intrinsic Functions</a>
161 <ol>
162 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
163 <ol>
164 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
165 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
166 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
167 </ol>
168 </li>
169 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
170 <ol>
171 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
172 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
173 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
174 </ol>
175 </li>
176 <li><a href="#int_codegen">Code Generator Intrinsics</a>
177 <ol>
178 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
179 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
180 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
181 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
182 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
183 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
184 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
185 </ol>
186 </li>
187 <li><a href="#int_libc">Standard C Library Intrinsics</a>
188 <ol>
189 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
190 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
191 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
192 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
193 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]194 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
195 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
196 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]197 </ol>
198 </li>
199 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
200 <ol>
201 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
202 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
203 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
204 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
205 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
206 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
207 </ol>
208 </li>
209 <li><a href="#int_debugger">Debugger intrinsics</a></li>
210 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]211 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]212 <ol>
213 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]214 </ol>
215 </li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]216 <li><a href="#int_atomics">Atomic intrinsics</a>
217 <ol>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]218 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]219 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]220 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]221 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
222 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
223 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
224 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
225 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
226 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
227 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
228 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
229 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
230 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]231 </ol>
232 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]233 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]234 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]235 <li><a href="#int_var_annotation">
Tanya Lattner51369f32007-09-22 00:01:26 +0000[diff] [blame]236 <tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]237 <li><a href="#int_annotation">
Tanya Lattner51369f32007-09-22 00:01:26 +0000[diff] [blame]238 <tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]239 <li><a href="#int_trap">
240 <tt>llvm.trap</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]241 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]242 </li>
243 </ol>
244 </li>
245</ol>
246
247<div class="doc_author">
248 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
249 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
250</div>
251
252<!-- *********************************************************************** -->
253<div class="doc_section"> <a name="abstract">Abstract </a></div>
254<!-- *********************************************************************** -->
255
256<div class="doc_text">
257<p>This document is a reference manual for the LLVM assembly language.
Bill Wendlinge7846a52008-08-05 22:29:16 +0000[diff] [blame]258LLVM is a Static Single Assignment (SSA) based representation that provides
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]259type safety, low-level operations, flexibility, and the capability of
260representing 'all' high-level languages cleanly. It is the common code
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]261representation used throughout all phases of the LLVM compilation
262strategy.</p>
263</div>
264
265<!-- *********************************************************************** -->
266<div class="doc_section"> <a name="introduction">Introduction</a> </div>
267<!-- *********************************************************************** -->
268
269<div class="doc_text">
270
271<p>The LLVM code representation is designed to be used in three
272different forms: as an in-memory compiler IR, as an on-disk bitcode
273representation (suitable for fast loading by a Just-In-Time compiler),
274and as a human readable assembly language representation. This allows
275LLVM to provide a powerful intermediate representation for efficient
276compiler transformations and analysis, while providing a natural means
277to debug and visualize the transformations. The three different forms
278of LLVM are all equivalent. This document describes the human readable
279representation and notation.</p>
280
281<p>The LLVM representation aims to be light-weight and low-level
282while being expressive, typed, and extensible at the same time. It
283aims to be a "universal IR" of sorts, by being at a low enough level
284that high-level ideas may be cleanly mapped to it (similar to how
285microprocessors are "universal IR's", allowing many source languages to
286be mapped to them). By providing type information, LLVM can be used as
287the target of optimizations: for example, through pointer analysis, it
288can be proven that a C automatic variable is never accessed outside of
289the current function... allowing it to be promoted to a simple SSA
290value instead of a memory location.</p>
291
292</div>
293
294<!-- _______________________________________________________________________ -->
295<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
296
297<div class="doc_text">
298
299<p>It is important to note that this document describes 'well formed'
300LLVM assembly language. There is a difference between what the parser
301accepts and what is considered 'well formed'. For example, the
302following instruction is syntactically okay, but not well formed:</p>
303
304<div class="doc_code">
305<pre>
306%x = <a href="#i_add">add</a> i32 1, %x
307</pre>
308</div>
309
310<p>...because the definition of <tt>%x</tt> does not dominate all of
311its uses. The LLVM infrastructure provides a verification pass that may
312be used to verify that an LLVM module is well formed. This pass is
313automatically run by the parser after parsing input assembly and by
314the optimizer before it outputs bitcode. The violations pointed out
315by the verifier pass indicate bugs in transformation passes or input to
316the parser.</p>
317</div>
318
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]319<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]320
321<!-- *********************************************************************** -->
322<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
323<!-- *********************************************************************** -->
324
325<div class="doc_text">
326
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]327 <p>LLVM identifiers come in two basic types: global and local. Global
328 identifiers (functions, global variables) begin with the @ character. Local
329 identifiers (register names, types) begin with the % character. Additionally,
330 there are three different formats for identifiers, for different purposes:
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]331
332<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]333 <li>Named values are represented as a string of characters with their prefix.
334 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
335 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]336 Identifiers which require other characters in their names can be surrounded
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]337 with quotes. In this way, anything except a <tt>&quot;</tt> character can
338 be used in a named value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]339
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]340 <li>Unnamed values are represented as an unsigned numeric value with their
341 prefix. For example, %12, @2, %44.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]342
343 <li>Constants, which are described in a <a href="#constants">section about
344 constants</a>, below.</li>
345</ol>
346
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]347<p>LLVM requires that values start with a prefix for two reasons: Compilers
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]348don't need to worry about name clashes with reserved words, and the set of
349reserved words may be expanded in the future without penalty. Additionally,
350unnamed identifiers allow a compiler to quickly come up with a temporary
351variable without having to avoid symbol table conflicts.</p>
352
353<p>Reserved words in LLVM are very similar to reserved words in other
354languages. There are keywords for different opcodes
355('<tt><a href="#i_add">add</a></tt>',
356 '<tt><a href="#i_bitcast">bitcast</a></tt>',
357 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
358href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
359and others. These reserved words cannot conflict with variable names, because
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]360none of them start with a prefix character ('%' or '@').</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]361
362<p>Here is an example of LLVM code to multiply the integer variable
363'<tt>%X</tt>' by 8:</p>
364
365<p>The easy way:</p>
366
367<div class="doc_code">
368<pre>
369%result = <a href="#i_mul">mul</a> i32 %X, 8
370</pre>
371</div>
372
373<p>After strength reduction:</p>
374
375<div class="doc_code">
376<pre>
377%result = <a href="#i_shl">shl</a> i32 %X, i8 3
378</pre>
379</div>
380
381<p>And the hard way:</p>
382
383<div class="doc_code">
384<pre>
385<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
386<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
387%result = <a href="#i_add">add</a> i32 %1, %1
388</pre>
389</div>
390
391<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
392important lexical features of LLVM:</p>
393
394<ol>
395
396 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
397 line.</li>
398
399 <li>Unnamed temporaries are created when the result of a computation is not
400 assigned to a named value.</li>
401
402 <li>Unnamed temporaries are numbered sequentially</li>
403
404</ol>
405
406<p>...and it also shows a convention that we follow in this document. When
407demonstrating instructions, we will follow an instruction with a comment that
408defines the type and name of value produced. Comments are shown in italic
409text.</p>
410
411</div>
412
413<!-- *********************************************************************** -->
414<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
415<!-- *********************************************************************** -->
416
417<!-- ======================================================================= -->
418<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
419</div>
420
421<div class="doc_text">
422
423<p>LLVM programs are composed of "Module"s, each of which is a
424translation unit of the input programs. Each module consists of
425functions, global variables, and symbol table entries. Modules may be
426combined together with the LLVM linker, which merges function (and
427global variable) definitions, resolves forward declarations, and merges
428symbol table entries. Here is an example of the "hello world" module:</p>
429
430<div class="doc_code">
431<pre><i>; Declare the string constant as a global constant...</i>
432<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
433 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
434
435<i>; External declaration of the puts function</i>
436<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
437
438<i>; Definition of main function</i>
439define i32 @main() { <i>; i32()* </i>
440 <i>; Convert [13x i8 ]* to i8 *...</i>
441 %cast210 = <a
442 href="#i_getelementptr">getelementptr</a> [13 x i8 ]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
443
444 <i>; Call puts function to write out the string to stdout...</i>
445 <a
446 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
447 <a
448 href="#i_ret">ret</a> i32 0<br>}<br>
449</pre>
450</div>
451
452<p>This example is made up of a <a href="#globalvars">global variable</a>
453named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
454function, and a <a href="#functionstructure">function definition</a>
455for "<tt>main</tt>".</p>
456
457<p>In general, a module is made up of a list of global values,
458where both functions and global variables are global values. Global values are
459represented by a pointer to a memory location (in this case, a pointer to an
460array of char, and a pointer to a function), and have one of the following <a
461href="#linkage">linkage types</a>.</p>
462
463</div>
464
465<!-- ======================================================================= -->
466<div class="doc_subsection">
467 <a name="linkage">Linkage Types</a>
468</div>
469
470<div class="doc_text">
471
472<p>
473All Global Variables and Functions have one of the following types of linkage:
474</p>
475
476<dl>
477
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]478 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]479
480 <dd>Global values with internal linkage are only directly accessible by
481 objects in the current module. In particular, linking code into a module with
482 an internal global value may cause the internal to be renamed as necessary to
483 avoid collisions. Because the symbol is internal to the module, all
484 references can be updated. This corresponds to the notion of the
485 '<tt>static</tt>' keyword in C.
486 </dd>
487
488 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
489
490 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
491 the same name when linkage occurs. This is typically used to implement
492 inline functions, templates, or other code which must be generated in each
493 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
494 allowed to be discarded.
495 </dd>
496
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]497 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
498
499 <dd>"<tt>common</tt>" linkage is exactly the same as <tt>linkonce</tt>
500 linkage, except that unreferenced <tt>common</tt> globals may not be
501 discarded. This is used for globals that may be emitted in multiple
502 translation units, but that are not guaranteed to be emitted into every
503 translation unit that uses them. One example of this is tentative
504 definitions in C, such as "<tt>int X;</tt>" at global scope.
505 </dd>
506
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]507 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
508
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]509 <dd>"<tt>weak</tt>" linkage is the same as <tt>common</tt> linkage, except
510 that some targets may choose to emit different assembly sequences for them
511 for target-dependent reasons. This is used for globals that are declared
512 "weak" in C source code.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]513 </dd>
514
515 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
516
517 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
518 pointer to array type. When two global variables with appending linkage are
519 linked together, the two global arrays are appended together. This is the
520 LLVM, typesafe, equivalent of having the system linker append together
521 "sections" with identical names when .o files are linked.
522 </dd>
523
524 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]525 <dd>The semantics of this linkage follow the ELF object file model: the
526 symbol is weak until linked, if not linked, the symbol becomes null instead
527 of being an undefined reference.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]528 </dd>
529
530 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
531
532 <dd>If none of the above identifiers are used, the global is externally
533 visible, meaning that it participates in linkage and can be used to resolve
534 external symbol references.
535 </dd>
536</dl>
537
538 <p>
539 The next two types of linkage are targeted for Microsoft Windows platform
540 only. They are designed to support importing (exporting) symbols from (to)
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]541 DLLs (Dynamic Link Libraries).
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]542 </p>
543
544 <dl>
545 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
546
547 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
548 or variable via a global pointer to a pointer that is set up by the DLL
549 exporting the symbol. On Microsoft Windows targets, the pointer name is
550 formed by combining <code>_imp__</code> and the function or variable name.
551 </dd>
552
553 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
554
555 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
556 pointer to a pointer in a DLL, so that it can be referenced with the
557 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
558 name is formed by combining <code>_imp__</code> and the function or variable
559 name.
560 </dd>
561
562</dl>
563
564<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
565variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
566variable and was linked with this one, one of the two would be renamed,
567preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
568external (i.e., lacking any linkage declarations), they are accessible
569outside of the current module.</p>
570<p>It is illegal for a function <i>declaration</i>
571to have any linkage type other than "externally visible", <tt>dllimport</tt>,
572or <tt>extern_weak</tt>.</p>
573<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
574linkages.
575</div>
576
577<!-- ======================================================================= -->
578<div class="doc_subsection">
579 <a name="callingconv">Calling Conventions</a>
580</div>
581
582<div class="doc_text">
583
584<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
585and <a href="#i_invoke">invokes</a> can all have an optional calling convention
586specified for the call. The calling convention of any pair of dynamic
587caller/callee must match, or the behavior of the program is undefined. The
588following calling conventions are supported by LLVM, and more may be added in
589the future:</p>
590
591<dl>
592 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
593
594 <dd>This calling convention (the default if no other calling convention is
595 specified) matches the target C calling conventions. This calling convention
596 supports varargs function calls and tolerates some mismatch in the declared
597 prototype and implemented declaration of the function (as does normal C).
598 </dd>
599
600 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
601
602 <dd>This calling convention attempts to make calls as fast as possible
603 (e.g. by passing things in registers). This calling convention allows the
604 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]605 without having to conform to an externally specified ABI (Application Binary
606 Interface). Implementations of this convention should allow arbitrary
Arnold Schwaighofer07444922008-05-14 09:17:12 +0000[diff] [blame]607 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> to be
608 supported. This calling convention does not support varargs and requires the
609 prototype of all callees to exactly match the prototype of the function
610 definition.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]611 </dd>
612
613 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
614
615 <dd>This calling convention attempts to make code in the caller as efficient
616 as possible under the assumption that the call is not commonly executed. As
617 such, these calls often preserve all registers so that the call does not break
618 any live ranges in the caller side. This calling convention does not support
619 varargs and requires the prototype of all callees to exactly match the
620 prototype of the function definition.
621 </dd>
622
623 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
624
625 <dd>Any calling convention may be specified by number, allowing
626 target-specific calling conventions to be used. Target specific calling
627 conventions start at 64.
628 </dd>
629</dl>
630
631<p>More calling conventions can be added/defined on an as-needed basis, to
632support pascal conventions or any other well-known target-independent
633convention.</p>
634
635</div>
636
637<!-- ======================================================================= -->
638<div class="doc_subsection">
639 <a name="visibility">Visibility Styles</a>
640</div>
641
642<div class="doc_text">
643
644<p>
645All Global Variables and Functions have one of the following visibility styles:
646</p>
647
648<dl>
649 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
650
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]651 <dd>On targets that use the ELF object file format, default visibility means
652 that the declaration is visible to other
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]653 modules and, in shared libraries, means that the declared entity may be
654 overridden. On Darwin, default visibility means that the declaration is
655 visible to other modules. Default visibility corresponds to "external
656 linkage" in the language.
657 </dd>
658
659 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
660
661 <dd>Two declarations of an object with hidden visibility refer to the same
662 object if they are in the same shared object. Usually, hidden visibility
663 indicates that the symbol will not be placed into the dynamic symbol table,
664 so no other module (executable or shared library) can reference it
665 directly.
666 </dd>
667
668 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
669
670 <dd>On ELF, protected visibility indicates that the symbol will be placed in
671 the dynamic symbol table, but that references within the defining module will
672 bind to the local symbol. That is, the symbol cannot be overridden by another
673 module.
674 </dd>
675</dl>
676
677</div>
678
679<!-- ======================================================================= -->
680<div class="doc_subsection">
681 <a name="globalvars">Global Variables</a>
682</div>
683
684<div class="doc_text">
685
686<p>Global variables define regions of memory allocated at compilation time
687instead of run-time. Global variables may optionally be initialized, may have
688an explicit section to be placed in, and may have an optional explicit alignment
689specified. A variable may be defined as "thread_local", which means that it
690will not be shared by threads (each thread will have a separated copy of the
691variable). A variable may be defined as a global "constant," which indicates
692that the contents of the variable will <b>never</b> be modified (enabling better
693optimization, allowing the global data to be placed in the read-only section of
694an executable, etc). Note that variables that need runtime initialization
695cannot be marked "constant" as there is a store to the variable.</p>
696
697<p>
698LLVM explicitly allows <em>declarations</em> of global variables to be marked
699constant, even if the final definition of the global is not. This capability
700can be used to enable slightly better optimization of the program, but requires
701the language definition to guarantee that optimizations based on the
702'constantness' are valid for the translation units that do not include the
703definition.
704</p>
705
706<p>As SSA values, global variables define pointer values that are in
707scope (i.e. they dominate) all basic blocks in the program. Global
708variables always define a pointer to their "content" type because they
709describe a region of memory, and all memory objects in LLVM are
710accessed through pointers.</p>
711
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]712<p>A global variable may be declared to reside in a target-specifc numbered
713address space. For targets that support them, address spaces may affect how
714optimizations are performed and/or what target instructions are used to access
Christopher Lamb20a39e92007-12-12 08:44:39 +0000[diff] [blame]715the variable. The default address space is zero. The address space qualifier
716must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]717
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]718<p>LLVM allows an explicit section to be specified for globals. If the target
719supports it, it will emit globals to the section specified.</p>
720
721<p>An explicit alignment may be specified for a global. If not present, or if
722the alignment is set to zero, the alignment of the global is set by the target
723to whatever it feels convenient. If an explicit alignment is specified, the
724global is forced to have at least that much alignment. All alignments must be
725a power of 2.</p>
726
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]727<p>For example, the following defines a global in a numbered address space with
728an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]729
730<div class="doc_code">
731<pre>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]732@G = constant float 1.0 addrspace(5), section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]733</pre>
734</div>
735
736</div>
737
738
739<!-- ======================================================================= -->
740<div class="doc_subsection">
741 <a name="functionstructure">Functions</a>
742</div>
743
744<div class="doc_text">
745
746<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
747an optional <a href="#linkage">linkage type</a>, an optional
748<a href="#visibility">visibility style</a>, an optional
749<a href="#callingconv">calling convention</a>, a return type, an optional
750<a href="#paramattrs">parameter attribute</a> for the return type, a function
751name, a (possibly empty) argument list (each with optional
752<a href="#paramattrs">parameter attributes</a>), an optional section, an
Gordon Henriksend606f5b2007-12-10 03:30:21 +0000[diff] [blame]753optional alignment, an optional <a href="#gc">garbage collector name</a>, an
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]754opening curly brace, a list of basic blocks, and a closing curly brace.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]755
756LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
757optional <a href="#linkage">linkage type</a>, an optional
758<a href="#visibility">visibility style</a>, an optional
759<a href="#callingconv">calling convention</a>, a return type, an optional
760<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]761name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksend606f5b2007-12-10 03:30:21 +0000[diff] [blame]762<a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]763
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]764<p>A function definition contains a list of basic blocks, forming the CFG
765(Control Flow Graph) for
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]766the function. Each basic block may optionally start with a label (giving the
767basic block a symbol table entry), contains a list of instructions, and ends
768with a <a href="#terminators">terminator</a> instruction (such as a branch or
769function return).</p>
770
771<p>The first basic block in a function is special in two ways: it is immediately
772executed on entrance to the function, and it is not allowed to have predecessor
773basic blocks (i.e. there can not be any branches to the entry block of a
774function). Because the block can have no predecessors, it also cannot have any
775<a href="#i_phi">PHI nodes</a>.</p>
776
777<p>LLVM allows an explicit section to be specified for functions. If the target
778supports it, it will emit functions to the section specified.</p>
779
780<p>An explicit alignment may be specified for a function. If not present, or if
781the alignment is set to zero, the alignment of the function is set by the target
782to whatever it feels convenient. If an explicit alignment is specified, the
783function is forced to have at least that much alignment. All alignments must be
784a power of 2.</p>
785
786</div>
787
788
789<!-- ======================================================================= -->
790<div class="doc_subsection">
791 <a name="aliasstructure">Aliases</a>
792</div>
793<div class="doc_text">
794 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikov96822812008-03-22 08:36:14 +0000[diff] [blame]795 function, global variable, another alias or bitcast of global value). Aliases
796 may have an optional <a href="#linkage">linkage type</a>, and an
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]797 optional <a href="#visibility">visibility style</a>.</p>
798
799 <h5>Syntax:</h5>
800
801<div class="doc_code">
802<pre>
803@&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
804</pre>
805</div>
806
807</div>
808
809
810
811<!-- ======================================================================= -->
812<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
813<div class="doc_text">
814 <p>The return type and each parameter of a function type may have a set of
815 <i>parameter attributes</i> associated with them. Parameter attributes are
816 used to communicate additional information about the result or parameters of
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]817 a function. Parameter attributes are considered to be part of the function,
818 not of the function type, so functions with different parameter attributes
819 can have the same function type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]820
821 <p>Parameter attributes are simple keywords that follow the type specified. If
822 multiple parameter attributes are needed, they are space separated. For
823 example:</p>
824
825<div class="doc_code">
826<pre>
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]827declare i32 @printf(i8* noalias , ...) nounwind
828declare i32 @atoi(i8*) nounwind readonly
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]829</pre>
830</div>
831
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]832 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
833 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]834
835 <p>Currently, only the following parameter attributes are defined:</p>
836 <dl>
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]837 <dt><tt>zeroext</tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]838 <dd>This indicates that the parameter should be zero extended just before
839 a call to this function.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]840
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]841 <dt><tt>signext</tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]842 <dd>This indicates that the parameter should be sign extended just before
843 a call to this function.</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>inreg</tt></dt>
846 <dd>This indicates that the parameter should be placed in register (if
847 possible) during assembling function call. Support for this attribute is
848 target-specific</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]849
850 <dt><tt>byval</tt></dt>
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]851 <dd>This indicates that the pointer parameter should really be passed by
852 value to the function. The attribute implies that a hidden copy of the
853 pointee is made between the caller and the callee, so the callee is unable
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]854 to modify the value in the callee. This attribute is only valid on LLVM
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]855 pointer arguments. It is generally used to pass structs and arrays by
856 value, but is also valid on scalars (even though this is silly).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]857
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]858 <dt><tt>sret</tt></dt>
Duncan Sands616cc032008-02-18 04:19:38 +0000[diff] [blame]859 <dd>This indicates that the pointer parameter specifies the address of a
860 structure that is the return value of the function in the source program.
Duncan Sandsef0e9e42008-03-17 12:17:41 +0000[diff] [blame]861 Loads and stores to the structure are assumed not to trap.
Duncan Sands616cc032008-02-18 04:19:38 +0000[diff] [blame]862 May only be applied to the first parameter.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]863
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]864 <dt><tt>noalias</tt></dt>
Owen Andersonc4fc4cd2008-02-18 04:09:01 +0000[diff] [blame]865 <dd>This indicates that the parameter does not alias any global or any other
866 parameter. The caller is responsible for ensuring that this is the case,
867 usually by placing the value in a stack allocation.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]868
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]869 <dt><tt>noreturn</tt></dt>
870 <dd>This function attribute indicates that the function never returns. This
871 indicates to LLVM that every call to this function should be treated as if
872 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]873
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]874 <dt><tt>nounwind</tt></dt>
Duncan Sandsef0e9e42008-03-17 12:17:41 +0000[diff] [blame]875 <dd>This function attribute indicates that no exceptions unwind out of the
876 function. Usually this is because the function makes no use of exceptions,
877 but it may also be that the function catches any exceptions thrown when
878 executing it.</dd>
879
Duncan Sands4ee46812007-07-27 19:57:41 +0000[diff] [blame]880 <dt><tt>nest</tt></dt>
Duncan Sandsf1a7d4c2008-07-08 09:27:25 +0000[diff] [blame]881 <dd>This indicates that the pointer parameter can be excised using the
Duncan Sands4ee46812007-07-27 19:57:41 +0000[diff] [blame]882 <a href="#int_trampoline">trampoline intrinsics</a>.</dd>
Duncan Sands13e13f82007-11-22 20:23:04 +0000[diff] [blame]883 <dt><tt>readonly</tt></dt>
Duncan Sandsd69c0e62007-11-14 21:14:02 +0000[diff] [blame]884 <dd>This function attribute indicates that the function has no side-effects
Duncan Sands13e13f82007-11-22 20:23:04 +0000[diff] [blame]885 except for producing a return value or throwing an exception. The value
886 returned must only depend on the function arguments and/or global variables.
887 It may use values obtained by dereferencing pointers.</dd>
888 <dt><tt>readnone</tt></dt>
889 <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]890 function, but in addition it is not allowed to dereference any pointer arguments
891 or global variables.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]892 </dl>
893
894</div>
895
896<!-- ======================================================================= -->
897<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]898 <a name="gc">Garbage Collector Names</a>
899</div>
900
901<div class="doc_text">
902<p>Each function may specify a garbage collector name, which is simply a
903string.</p>
904
905<div class="doc_code"><pre
906>define void @f() gc "name" { ...</pre></div>
907
908<p>The compiler declares the supported values of <i>name</i>. Specifying a
909collector which will cause the compiler to alter its output in order to support
910the named garbage collection algorithm.</p>
911</div>
912
913<!-- ======================================================================= -->
914<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]915 <a name="moduleasm">Module-Level Inline Assembly</a>
916</div>
917
918<div class="doc_text">
919<p>
920Modules may contain "module-level inline asm" blocks, which corresponds to the
921GCC "file scope inline asm" blocks. These blocks are internally concatenated by
922LLVM and treated as a single unit, but may be separated in the .ll file if
923desired. The syntax is very simple:
924</p>
925
926<div class="doc_code">
927<pre>
928module asm "inline asm code goes here"
929module asm "more can go here"
930</pre>
931</div>
932
933<p>The strings can contain any character by escaping non-printable characters.
934 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
935 for the number.
936</p>
937
938<p>
939 The inline asm code is simply printed to the machine code .s file when
940 assembly code is generated.
941</p>
942</div>
943
944<!-- ======================================================================= -->
945<div class="doc_subsection">
946 <a name="datalayout">Data Layout</a>
947</div>
948
949<div class="doc_text">
950<p>A module may specify a target specific data layout string that specifies how
951data is to be laid out in memory. The syntax for the data layout is simply:</p>
952<pre> target datalayout = "<i>layout specification</i>"</pre>
953<p>The <i>layout specification</i> consists of a list of specifications
954separated by the minus sign character ('-'). Each specification starts with a
955letter and may include other information after the letter to define some
956aspect of the data layout. The specifications accepted are as follows: </p>
957<dl>
958 <dt><tt>E</tt></dt>
959 <dd>Specifies that the target lays out data in big-endian form. That is, the
960 bits with the most significance have the lowest address location.</dd>
961 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]962 <dd>Specifies that the target lays out data in little-endian form. That is,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]963 the bits with the least significance have the lowest address location.</dd>
964 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
965 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
966 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
967 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
968 too.</dd>
969 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
970 <dd>This specifies the alignment for an integer type of a given bit
971 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
972 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
973 <dd>This specifies the alignment for a vector type of a given bit
974 <i>size</i>.</dd>
975 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
976 <dd>This specifies the alignment for a floating point type of a given bit
977 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
978 (double).</dd>
979 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
980 <dd>This specifies the alignment for an aggregate type of a given bit
981 <i>size</i>.</dd>
982</dl>
983<p>When constructing the data layout for a given target, LLVM starts with a
984default set of specifications which are then (possibly) overriden by the
985specifications in the <tt>datalayout</tt> keyword. The default specifications
986are given in this list:</p>
987<ul>
988 <li><tt>E</tt> - big endian</li>
989 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
990 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
991 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
992 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
993 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]994 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]995 alignment of 64-bits</li>
996 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
997 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
998 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
999 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1000 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
1001</ul>
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]1002<p>When LLVM is determining the alignment for a given type, it uses the
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1003following rules:
1004<ol>
1005 <li>If the type sought is an exact match for one of the specifications, that
1006 specification is used.</li>
1007 <li>If no match is found, and the type sought is an integer type, then the
1008 smallest integer type that is larger than the bitwidth of the sought type is
1009 used. If none of the specifications are larger than the bitwidth then the the
1010 largest integer type is used. For example, given the default specifications
1011 above, the i7 type will use the alignment of i8 (next largest) while both
1012 i65 and i256 will use the alignment of i64 (largest specified).</li>
1013 <li>If no match is found, and the type sought is a vector type, then the
1014 largest vector type that is smaller than the sought vector type will be used
1015 as a fall back. This happens because <128 x double> can be implemented in
1016 terms of 64 <2 x double>, for example.</li>
1017</ol>
1018</div>
1019
1020<!-- *********************************************************************** -->
1021<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1022<!-- *********************************************************************** -->
1023
1024<div class="doc_text">
1025
1026<p>The LLVM type system is one of the most important features of the
1027intermediate representation. Being typed enables a number of
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1028optimizations to be performed on the intermediate representation directly,
1029without having to do
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1030extra analyses on the side before the transformation. A strong type
1031system makes it easier to read the generated code and enables novel
1032analyses and transformations that are not feasible to perform on normal
1033three address code representations.</p>
1034
1035</div>
1036
1037<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1038<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1039Classifications</a> </div>
1040<div class="doc_text">
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1041<p>The types fall into a few useful
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1042classifications:</p>
1043
1044<table border="1" cellspacing="0" cellpadding="4">
1045 <tbody>
1046 <tr><th>Classification</th><th>Types</th></tr>
1047 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1048 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1049 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1050 </tr>
1051 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1052 <td><a href="#t_floating">floating point</a></td>
1053 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1054 </tr>
1055 <tr>
1056 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1057 <td><a href="#t_integer">integer</a>,
1058 <a href="#t_floating">floating point</a>,
1059 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1060 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1061 <a href="#t_struct">structure</a>,
1062 <a href="#t_array">array</a>,
Dan Gohmand13951e2008-05-23 22:50:26 +0000[diff] [blame]1063 <a href="#t_label">label</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1064 </td>
1065 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1066 <tr>
1067 <td><a href="#t_primitive">primitive</a></td>
1068 <td><a href="#t_label">label</a>,
1069 <a href="#t_void">void</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1070 <a href="#t_floating">floating point</a>.</td>
1071 </tr>
1072 <tr>
1073 <td><a href="#t_derived">derived</a></td>
1074 <td><a href="#t_integer">integer</a>,
1075 <a href="#t_array">array</a>,
1076 <a href="#t_function">function</a>,
1077 <a href="#t_pointer">pointer</a>,
1078 <a href="#t_struct">structure</a>,
1079 <a href="#t_pstruct">packed structure</a>,
1080 <a href="#t_vector">vector</a>,
1081 <a href="#t_opaque">opaque</a>.
1082 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1083 </tbody>
1084</table>
1085
1086<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1087most important. Values of these types are the only ones which can be
1088produced by instructions, passed as arguments, or used as operands to
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]1089instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1090</div>
1091
1092<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1093<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1094
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1095<div class="doc_text">
1096<p>The primitive types are the fundamental building blocks of the LLVM
1097system.</p>
1098
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1099</div>
1100
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1101<!-- _______________________________________________________________________ -->
1102<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1103
1104<div class="doc_text">
1105 <table>
1106 <tbody>
1107 <tr><th>Type</th><th>Description</th></tr>
1108 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1109 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1110 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1111 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1112 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1113 </tbody>
1114 </table>
1115</div>
1116
1117<!-- _______________________________________________________________________ -->
1118<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1119
1120<div class="doc_text">
1121<h5>Overview:</h5>
1122<p>The void type does not represent any value and has no size.</p>
1123
1124<h5>Syntax:</h5>
1125
1126<pre>
1127 void
1128</pre>
1129</div>
1130
1131<!-- _______________________________________________________________________ -->
1132<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1133
1134<div class="doc_text">
1135<h5>Overview:</h5>
1136<p>The label type represents code labels.</p>
1137
1138<h5>Syntax:</h5>
1139
1140<pre>
1141 label
1142</pre>
1143</div>
1144
1145
1146<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1147<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1148
1149<div class="doc_text">
1150
1151<p>The real power in LLVM comes from the derived types in the system.
1152This is what allows a programmer to represent arrays, functions,
1153pointers, and other useful types. Note that these derived types may be
1154recursive: For example, it is possible to have a two dimensional array.</p>
1155
1156</div>
1157
1158<!-- _______________________________________________________________________ -->
1159<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1160
1161<div class="doc_text">
1162
1163<h5>Overview:</h5>
1164<p>The integer type is a very simple derived type that simply specifies an
1165arbitrary bit width for the integer type desired. Any bit width from 1 bit to
11662^23-1 (about 8 million) can be specified.</p>
1167
1168<h5>Syntax:</h5>
1169
1170<pre>
1171 iN
1172</pre>
1173
1174<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1175value.</p>
1176
1177<h5>Examples:</h5>
1178<table class="layout">
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1179 <tbody>
1180 <tr>
1181 <td><tt>i1</tt></td>
1182 <td>a single-bit integer.</td>
1183 </tr><tr>
1184 <td><tt>i32</tt></td>
1185 <td>a 32-bit integer.</td>
1186 </tr><tr>
1187 <td><tt>i1942652</tt></td>
1188 <td>a really big integer of over 1 million bits.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1189 </tr>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1190 </tbody>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1191</table>
1192</div>
1193
1194<!-- _______________________________________________________________________ -->
1195<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1196
1197<div class="doc_text">
1198
1199<h5>Overview:</h5>
1200
1201<p>The array type is a very simple derived type that arranges elements
1202sequentially in memory. The array type requires a size (number of
1203elements) and an underlying data type.</p>
1204
1205<h5>Syntax:</h5>
1206
1207<pre>
1208 [&lt;# elements&gt; x &lt;elementtype&gt;]
1209</pre>
1210
1211<p>The number of elements is a constant integer value; elementtype may
1212be any type with a size.</p>
1213
1214<h5>Examples:</h5>
1215<table class="layout">
1216 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1217 <td class="left"><tt>[40 x i32]</tt></td>
1218 <td class="left">Array of 40 32-bit integer values.</td>
1219 </tr>
1220 <tr class="layout">
1221 <td class="left"><tt>[41 x i32]</tt></td>
1222 <td class="left">Array of 41 32-bit integer values.</td>
1223 </tr>
1224 <tr class="layout">
1225 <td class="left"><tt>[4 x i8]</tt></td>
1226 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1227 </tr>
1228</table>
1229<p>Here are some examples of multidimensional arrays:</p>
1230<table class="layout">
1231 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1232 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1233 <td class="left">3x4 array of 32-bit integer values.</td>
1234 </tr>
1235 <tr class="layout">
1236 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1237 <td class="left">12x10 array of single precision floating point values.</td>
1238 </tr>
1239 <tr class="layout">
1240 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1241 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1242 </tr>
1243</table>
1244
1245<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1246length array. Normally, accesses past the end of an array are undefined in
1247LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1248As a special case, however, zero length arrays are recognized to be variable
1249length. This allows implementation of 'pascal style arrays' with the LLVM
1250type "{ i32, [0 x float]}", for example.</p>
1251
1252</div>
1253
1254<!-- _______________________________________________________________________ -->
1255<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
1256<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1257
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1258<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1259
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1260<p>The function type can be thought of as a function signature. It
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1261consists of a return type and a list of formal parameter types. The
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1262return 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]1263If 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]1264class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1265
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1266<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1267
1268<pre>
1269 &lt;returntype list&gt; (&lt;parameter list&gt;)
1270</pre>
1271
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1272<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
1273specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1274which indicates that the function takes a variable number of arguments.
1275Variable argument functions can access their arguments with the <a
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1276 href="#int_varargs">variable argument handling intrinsic</a> functions.
1277'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1278<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1279
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1280<h5>Examples:</h5>
1281<table class="layout">
1282 <tr class="layout">
1283 <td class="left"><tt>i32 (i32)</tt></td>
1284 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1285 </td>
1286 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1287 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1288 </tt></td>
1289 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1290 an <tt>i16</tt> that should be sign extended and a
1291 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1292 <tt>float</tt>.
1293 </td>
1294 </tr><tr class="layout">
1295 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1296 <td class="left">A vararg function that takes at least one
1297 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1298 which returns an integer. This is the signature for <tt>printf</tt> in
1299 LLVM.
1300 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1301 </tr><tr class="layout">
1302 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Devang Patel6dddba22008-03-24 18:10:52 +0000[diff] [blame]1303 <td class="left">A function taking an <tt>i32></tt>, returning two
1304 <tt> i32 </tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1305 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1306 </tr>
1307</table>
1308
1309</div>
1310<!-- _______________________________________________________________________ -->
1311<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
1312<div class="doc_text">
1313<h5>Overview:</h5>
1314<p>The structure type is used to represent a collection of data members
1315together in memory. The packing of the field types is defined to match
1316the ABI of the underlying processor. The elements of a structure may
1317be any type that has a size.</p>
1318<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1319and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1320field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1321instruction.</p>
1322<h5>Syntax:</h5>
1323<pre> { &lt;type list&gt; }<br></pre>
1324<h5>Examples:</h5>
1325<table class="layout">
1326 <tr class="layout">
1327 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1328 <td class="left">A triple of three <tt>i32</tt> values</td>
1329 </tr><tr class="layout">
1330 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1331 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1332 second element is a <a href="#t_pointer">pointer</a> to a
1333 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1334 an <tt>i32</tt>.</td>
1335 </tr>
1336</table>
1337</div>
1338
1339<!-- _______________________________________________________________________ -->
1340<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1341</div>
1342<div class="doc_text">
1343<h5>Overview:</h5>
1344<p>The packed structure type is used to represent a collection of data members
1345together in memory. There is no padding between fields. Further, the alignment
1346of a packed structure is 1 byte. The elements of a packed structure may
1347be any type that has a size.</p>
1348<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1349and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1350field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1351instruction.</p>
1352<h5>Syntax:</h5>
1353<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1354<h5>Examples:</h5>
1355<table class="layout">
1356 <tr class="layout">
1357 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1358 <td class="left">A triple of three <tt>i32</tt> values</td>
1359 </tr><tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1360 <td class="left"><tt>&lt; { float, i32 (i32)* } &gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1361 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1362 second element is a <a href="#t_pointer">pointer</a> to a
1363 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1364 an <tt>i32</tt>.</td>
1365 </tr>
1366</table>
1367</div>
1368
1369<!-- _______________________________________________________________________ -->
1370<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
1371<div class="doc_text">
1372<h5>Overview:</h5>
1373<p>As in many languages, the pointer type represents a pointer or
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]1374reference to another object, which must live in memory. Pointer types may have
1375an optional address space attribute defining the target-specific numbered
1376address space where the pointed-to object resides. The default address space is
1377zero.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1378<h5>Syntax:</h5>
1379<pre> &lt;type&gt; *<br></pre>
1380<h5>Examples:</h5>
1381<table class="layout">
1382 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1383 <td class="left"><tt>[4x i32]*</tt></td>
1384 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1385 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1386 </tr>
1387 <tr class="layout">
1388 <td class="left"><tt>i32 (i32 *) *</tt></td>
1389 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1390 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1391 <tt>i32</tt>.</td>
1392 </tr>
1393 <tr class="layout">
1394 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1395 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1396 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1397 </tr>
1398</table>
1399</div>
1400
1401<!-- _______________________________________________________________________ -->
1402<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
1403<div class="doc_text">
1404
1405<h5>Overview:</h5>
1406
1407<p>A vector type is a simple derived type that represents a vector
1408of elements. Vector types are used when multiple primitive data
1409are operated in parallel using a single instruction (SIMD).
1410A vector type requires a size (number of
1411elements) and an underlying primitive data type. Vectors must have a power
1412of two length (1, 2, 4, 8, 16 ...). Vector types are
1413considered <a href="#t_firstclass">first class</a>.</p>
1414
1415<h5>Syntax:</h5>
1416
1417<pre>
1418 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1419</pre>
1420
1421<p>The number of elements is a constant integer value; elementtype may
1422be any integer or floating point type.</p>
1423
1424<h5>Examples:</h5>
1425
1426<table class="layout">
1427 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1428 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1429 <td class="left">Vector of 4 32-bit integer values.</td>
1430 </tr>
1431 <tr class="layout">
1432 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1433 <td class="left">Vector of 8 32-bit floating-point values.</td>
1434 </tr>
1435 <tr class="layout">
1436 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1437 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1438 </tr>
1439</table>
1440</div>
1441
1442<!-- _______________________________________________________________________ -->
1443<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1444<div class="doc_text">
1445
1446<h5>Overview:</h5>
1447
1448<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksenda0706e2007-10-14 00:34:53 +0000[diff] [blame]1449corresponds (for example) to the C notion of a forward declared structure type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1450In LLVM, opaque types can eventually be resolved to any type (not just a
1451structure type).</p>
1452
1453<h5>Syntax:</h5>
1454
1455<pre>
1456 opaque
1457</pre>
1458
1459<h5>Examples:</h5>
1460
1461<table class="layout">
1462 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1463 <td class="left"><tt>opaque</tt></td>
1464 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1465 </tr>
1466</table>
1467</div>
1468
1469
1470<!-- *********************************************************************** -->
1471<div class="doc_section"> <a name="constants">Constants</a> </div>
1472<!-- *********************************************************************** -->
1473
1474<div class="doc_text">
1475
1476<p>LLVM has several different basic types of constants. This section describes
1477them all and their syntax.</p>
1478
1479</div>
1480
1481<!-- ======================================================================= -->
1482<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1483
1484<div class="doc_text">
1485
1486<dl>
1487 <dt><b>Boolean constants</b></dt>
1488
1489 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1490 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
1491 </dd>
1492
1493 <dt><b>Integer constants</b></dt>
1494
1495 <dd>Standard integers (such as '4') are constants of the <a
1496 href="#t_integer">integer</a> type. Negative numbers may be used with
1497 integer types.
1498 </dd>
1499
1500 <dt><b>Floating point constants</b></dt>
1501
1502 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1503 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]1504 notation (see below). The assembler requires the exact decimal value of
1505 a floating-point constant. For example, the assembler accepts 1.25 but
1506 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1507 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1508
1509 <dt><b>Null pointer constants</b></dt>
1510
1511 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
1512 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1513
1514</dl>
1515
1516<p>The one non-intuitive notation for constants is the optional hexadecimal form
1517of floating point constants. For example, the form '<tt>double
15180x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
15194.5e+15</tt>'. The only time hexadecimal floating point constants are required
1520(and the only time that they are generated by the disassembler) is when a
1521floating point constant must be emitted but it cannot be represented as a
1522decimal floating point number. For example, NaN's, infinities, and other
1523special values are represented in their IEEE hexadecimal format so that
1524assembly and disassembly do not cause any bits to change in the constants.</p>
1525
1526</div>
1527
1528<!-- ======================================================================= -->
1529<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1530</div>
1531
1532<div class="doc_text">
1533<p>Aggregate constants arise from aggregation of simple constants
1534and smaller aggregate constants.</p>
1535
1536<dl>
1537 <dt><b>Structure constants</b></dt>
1538
1539 <dd>Structure constants are represented with notation similar to structure
1540 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner6c8de962007-12-25 20:34:52 +0000[diff] [blame]1541 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1542 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]1543 must have <a href="#t_struct">structure type</a>, and the number and
1544 types of elements must match those specified by the type.
1545 </dd>
1546
1547 <dt><b>Array constants</b></dt>
1548
1549 <dd>Array constants are represented with notation similar to array type
1550 definitions (a comma separated list of elements, surrounded by square brackets
1551 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
1552 constants must have <a href="#t_array">array type</a>, and the number and
1553 types of elements must match those specified by the type.
1554 </dd>
1555
1556 <dt><b>Vector constants</b></dt>
1557
1558 <dd>Vector constants are represented with notation similar to vector type
1559 definitions (a comma separated list of elements, surrounded by
1560 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1561 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
1562 href="#t_vector">vector type</a>, and the number and types of elements must
1563 match those specified by the type.
1564 </dd>
1565
1566 <dt><b>Zero initialization</b></dt>
1567
1568 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1569 value to zero of <em>any</em> type, including scalar and aggregate types.
1570 This is often used to avoid having to print large zero initializers (e.g. for
1571 large arrays) and is always exactly equivalent to using explicit zero
1572 initializers.
1573 </dd>
1574</dl>
1575
1576</div>
1577
1578<!-- ======================================================================= -->
1579<div class="doc_subsection">
1580 <a name="globalconstants">Global Variable and Function Addresses</a>
1581</div>
1582
1583<div class="doc_text">
1584
1585<p>The addresses of <a href="#globalvars">global variables</a> and <a
1586href="#functionstructure">functions</a> are always implicitly valid (link-time)
1587constants. These constants are explicitly referenced when the <a
1588href="#identifiers">identifier for the global</a> is used and always have <a
1589href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1590file:</p>
1591
1592<div class="doc_code">
1593<pre>
1594@X = global i32 17
1595@Y = global i32 42
1596@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
1597</pre>
1598</div>
1599
1600</div>
1601
1602<!-- ======================================================================= -->
1603<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
1604<div class="doc_text">
1605 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
1606 no specific value. Undefined values may be of any type and be used anywhere
1607 a constant is permitted.</p>
1608
1609 <p>Undefined values indicate to the compiler that the program is well defined
1610 no matter what value is used, giving the compiler more freedom to optimize.
1611 </p>
1612</div>
1613
1614<!-- ======================================================================= -->
1615<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1616</div>
1617
1618<div class="doc_text">
1619
1620<p>Constant expressions are used to allow expressions involving other constants
1621to be used as constants. Constant expressions may be of any <a
1622href="#t_firstclass">first class</a> type and may involve any LLVM operation
1623that does not have side effects (e.g. load and call are not supported). The
1624following is the syntax for constant expressions:</p>
1625
1626<dl>
1627 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1628 <dd>Truncate a constant to another type. The bit size of CST must be larger
1629 than the bit size of TYPE. Both types must be integers.</dd>
1630
1631 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1632 <dd>Zero extend a constant to another type. The bit size of CST must be
1633 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1634
1635 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1636 <dd>Sign extend a constant to another type. The bit size of CST must be
1637 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1638
1639 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1640 <dd>Truncate a floating point constant to another floating point type. The
1641 size of CST must be larger than the size of TYPE. Both types must be
1642 floating point.</dd>
1643
1644 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1645 <dd>Floating point extend a constant to another type. The size of CST must be
1646 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1647
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]1648 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1649 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1650 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1651 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1652 of the same number of elements. If the value won't fit in the integer type,
1653 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1654
1655 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
1656 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1657 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1658 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1659 of the same number of elements. If the value won't fit in the integer type,
1660 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1661
1662 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
1663 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1664 constant. TYPE must be a scalar or vector floating point type. CST must be of
1665 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1666 of the same number of elements. If the value won't fit in the floating point
1667 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1668
1669 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
1670 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1671 constant. TYPE must be a scalar or vector floating point type. CST must be of
1672 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1673 of the same number of elements. If the value won't fit in the floating point
1674 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1675
1676 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1677 <dd>Convert a pointer typed constant to the corresponding integer constant
1678 TYPE must be an integer type. CST must be of pointer type. The CST value is
1679 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1680
1681 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1682 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1683 pointer type. CST must be of integer type. The CST value is zero extended,
1684 truncated, or unchanged to make it fit in a pointer size. This one is
1685 <i>really</i> dangerous!</dd>
1686
1687 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
1688 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1689 identical (same number of bits). The conversion is done as if the CST value
1690 was stored to memory and read back as TYPE. In other words, no bits change
1691 with this operator, just the type. This can be used for conversion of
1692 vector types to any other type, as long as they have the same bit width. For
1693 pointers it is only valid to cast to another pointer type.
1694 </dd>
1695
1696 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1697
1698 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1699 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1700 instruction, the index list may have zero or more indexes, which are required
1701 to make sense for the type of "CSTPTR".</dd>
1702
1703 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1704
1705 <dd>Perform the <a href="#i_select">select operation</a> on
1706 constants.</dd>
1707
1708 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1709 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1710
1711 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1712 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
1713
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]1714 <dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
1715 <dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
1716
1717 <dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
1718 <dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
1719
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1720 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1721
1722 <dd>Perform the <a href="#i_extractelement">extractelement
1723 operation</a> on constants.
1724
1725 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1726
1727 <dd>Perform the <a href="#i_insertelement">insertelement
1728 operation</a> on constants.</dd>
1729
1730
1731 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1732
1733 <dd>Perform the <a href="#i_shufflevector">shufflevector
1734 operation</a> on constants.</dd>
1735
1736 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1737
1738 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1739 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
1740 binary</a> operations. The constraints on operands are the same as those for
1741 the corresponding instruction (e.g. no bitwise operations on floating point
1742 values are allowed).</dd>
1743</dl>
1744</div>
1745
1746<!-- *********************************************************************** -->
1747<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1748<!-- *********************************************************************** -->
1749
1750<!-- ======================================================================= -->
1751<div class="doc_subsection">
1752<a name="inlineasm">Inline Assembler Expressions</a>
1753</div>
1754
1755<div class="doc_text">
1756
1757<p>
1758LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1759Module-Level Inline Assembly</a>) through the use of a special value. This
1760value represents the inline assembler as a string (containing the instructions
1761to emit), a list of operand constraints (stored as a string), and a flag that
1762indicates whether or not the inline asm expression has side effects. An example
1763inline assembler expression is:
1764</p>
1765
1766<div class="doc_code">
1767<pre>
1768i32 (i32) asm "bswap $0", "=r,r"
1769</pre>
1770</div>
1771
1772<p>
1773Inline assembler expressions may <b>only</b> be used as the callee operand of
1774a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1775</p>
1776
1777<div class="doc_code">
1778<pre>
1779%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
1780</pre>
1781</div>
1782
1783<p>
1784Inline asms with side effects not visible in the constraint list must be marked
1785as having side effects. This is done through the use of the
1786'<tt>sideeffect</tt>' keyword, like so:
1787</p>
1788
1789<div class="doc_code">
1790<pre>
1791call void asm sideeffect "eieio", ""()
1792</pre>
1793</div>
1794
1795<p>TODO: The format of the asm and constraints string still need to be
1796documented here. Constraints on what can be done (e.g. duplication, moving, etc
1797need to be documented).
1798</p>
1799
1800</div>
1801
1802<!-- *********************************************************************** -->
1803<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1804<!-- *********************************************************************** -->
1805
1806<div class="doc_text">
1807
1808<p>The LLVM instruction set consists of several different
1809classifications of instructions: <a href="#terminators">terminator
1810instructions</a>, <a href="#binaryops">binary instructions</a>,
1811<a href="#bitwiseops">bitwise binary instructions</a>, <a
1812 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1813instructions</a>.</p>
1814
1815</div>
1816
1817<!-- ======================================================================= -->
1818<div class="doc_subsection"> <a name="terminators">Terminator
1819Instructions</a> </div>
1820
1821<div class="doc_text">
1822
1823<p>As mentioned <a href="#functionstructure">previously</a>, every
1824basic block in a program ends with a "Terminator" instruction, which
1825indicates which block should be executed after the current block is
1826finished. These terminator instructions typically yield a '<tt>void</tt>'
1827value: they produce control flow, not values (the one exception being
1828the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
1829<p>There are six different terminator instructions: the '<a
1830 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1831instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
1832the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1833 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1834 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
1835
1836</div>
1837
1838<!-- _______________________________________________________________________ -->
1839<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1840Instruction</a> </div>
1841<div class="doc_text">
1842<h5>Syntax:</h5>
1843<pre> ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
1844 ret void <i>; Return from void function</i>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1845 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]1846</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1847
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1848<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1849
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1850<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
1851value) from a function back to the caller.</p>
1852<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1853returns value(s) and then causes control flow, and one that just causes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1854control flow to occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1855
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1856<h5>Arguments:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1857
1858<p>The '<tt>ret</tt>' instruction may return zero, one or multiple values.
1859The type of each return value must be a '<a href="#t_firstclass">first
1860class</a>' type. Note that a function is not <a href="#wellformed">well
1861formed</a> if there exists a '<tt>ret</tt>' instruction inside of the
1862function that returns values that do not match the return type of the
1863function.</p>
1864
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1865<h5>Semantics:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1866
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1867<p>When the '<tt>ret</tt>' instruction is executed, control flow
1868returns back to the calling function's context. If the caller is a "<a
1869 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
1870the instruction after the call. If the caller was an "<a
1871 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
1872at the beginning of the "normal" destination block. If the instruction
1873returns a value, that value shall set the call or invoke instruction's
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1874return value. If the instruction returns multiple values then these
Devang Patelec8a5b02008-03-11 05:51:59 +0000[diff] [blame]1875values can only be accessed through a '<a href="#i_getresult"><tt>getresult</tt>
1876</a>' instruction.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1877
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1878<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1879
1880<pre>
1881 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1882 ret void <i>; Return from a void function</i>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1883 ret i32 4, i8 2 <i>; Return two values 4 and 2 </i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1884</pre>
1885</div>
1886<!-- _______________________________________________________________________ -->
1887<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
1888<div class="doc_text">
1889<h5>Syntax:</h5>
1890<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
1891</pre>
1892<h5>Overview:</h5>
1893<p>The '<tt>br</tt>' instruction is used to cause control flow to
1894transfer to a different basic block in the current function. There are
1895two forms of this instruction, corresponding to a conditional branch
1896and an unconditional branch.</p>
1897<h5>Arguments:</h5>
1898<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
1899single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
1900unconditional form of the '<tt>br</tt>' instruction takes a single
1901'<tt>label</tt>' value as a target.</p>
1902<h5>Semantics:</h5>
1903<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
1904argument is evaluated. If the value is <tt>true</tt>, control flows
1905to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1906control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
1907<h5>Example:</h5>
1908<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
1909 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
1910</div>
1911<!-- _______________________________________________________________________ -->
1912<div class="doc_subsubsection">
1913 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1914</div>
1915
1916<div class="doc_text">
1917<h5>Syntax:</h5>
1918
1919<pre>
1920 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1921</pre>
1922
1923<h5>Overview:</h5>
1924
1925<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1926several different places. It is a generalization of the '<tt>br</tt>'
1927instruction, allowing a branch to occur to one of many possible
1928destinations.</p>
1929
1930
1931<h5>Arguments:</h5>
1932
1933<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1934comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1935an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1936table is not allowed to contain duplicate constant entries.</p>
1937
1938<h5>Semantics:</h5>
1939
1940<p>The <tt>switch</tt> instruction specifies a table of values and
1941destinations. When the '<tt>switch</tt>' instruction is executed, this
1942table is searched for the given value. If the value is found, control flow is
1943transfered to the corresponding destination; otherwise, control flow is
1944transfered to the default destination.</p>
1945
1946<h5>Implementation:</h5>
1947
1948<p>Depending on properties of the target machine and the particular
1949<tt>switch</tt> instruction, this instruction may be code generated in different
1950ways. For example, it could be generated as a series of chained conditional
1951branches or with a lookup table.</p>
1952
1953<h5>Example:</h5>
1954
1955<pre>
1956 <i>; Emulate a conditional br instruction</i>
1957 %Val = <a href="#i_zext">zext</a> i1 %value to i32
1958 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
1959
1960 <i>; Emulate an unconditional br instruction</i>
1961 switch i32 0, label %dest [ ]
1962
1963 <i>; Implement a jump table:</i>
1964 switch i32 %val, label %otherwise [ i32 0, label %onzero
1965 i32 1, label %onone
1966 i32 2, label %ontwo ]
1967</pre>
1968</div>
1969
1970<!-- _______________________________________________________________________ -->
1971<div class="doc_subsubsection">
1972 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1973</div>
1974
1975<div class="doc_text">
1976
1977<h5>Syntax:</h5>
1978
1979<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]1980 &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]1981 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
1982</pre>
1983
1984<h5>Overview:</h5>
1985
1986<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1987function, with the possibility of control flow transfer to either the
1988'<tt>normal</tt>' label or the
1989'<tt>exception</tt>' label. If the callee function returns with the
1990"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1991"normal" label. If the callee (or any indirect callees) returns with the "<a
1992href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1993continued at the dynamically nearest "exception" label. If the callee function
Devang Patelec8a5b02008-03-11 05:51:59 +0000[diff] [blame]1994returns multiple values then individual return values are only accessible through
1995a '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1996
1997<h5>Arguments:</h5>
1998
1999<p>This instruction requires several arguments:</p>
2000
2001<ol>
2002 <li>
2003 The optional "cconv" marker indicates which <a href="#callingconv">calling
2004 convention</a> the call should use. If none is specified, the call defaults
2005 to using C calling conventions.
2006 </li>
2007 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
2008 function value being invoked. In most cases, this is a direct function
2009 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
2010 an arbitrary pointer to function value.
2011 </li>
2012
2013 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
2014 function to be invoked. </li>
2015
2016 <li>'<tt>function args</tt>': argument list whose types match the function
2017 signature argument types. If the function signature indicates the function
2018 accepts a variable number of arguments, the extra arguments can be
2019 specified. </li>
2020
2021 <li>'<tt>normal label</tt>': the label reached when the called function
2022 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2023
2024 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2025 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2026
2027</ol>
2028
2029<h5>Semantics:</h5>
2030
2031<p>This instruction is designed to operate as a standard '<tt><a
2032href="#i_call">call</a></tt>' instruction in most regards. The primary
2033difference is that it establishes an association with a label, which is used by
2034the runtime library to unwind the stack.</p>
2035
2036<p>This instruction is used in languages with destructors to ensure that proper
2037cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2038exception. Additionally, this is important for implementation of
2039'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2040
2041<h5>Example:</h5>
2042<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2043 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2044 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2045 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2046 unwind label %TestCleanup <i>; {i32}:retval set</i>
2047</pre>
2048</div>
2049
2050
2051<!-- _______________________________________________________________________ -->
2052
2053<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2054Instruction</a> </div>
2055
2056<div class="doc_text">
2057
2058<h5>Syntax:</h5>
2059<pre>
2060 unwind
2061</pre>
2062
2063<h5>Overview:</h5>
2064
2065<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2066at the first callee in the dynamic call stack which used an <a
2067href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2068primarily used to implement exception handling.</p>
2069
2070<h5>Semantics:</h5>
2071
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2072<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2073immediately halt. The dynamic call stack is then searched for the first <a
2074href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2075execution continues at the "exceptional" destination block specified by the
2076<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2077dynamic call chain, undefined behavior results.</p>
2078</div>
2079
2080<!-- _______________________________________________________________________ -->
2081
2082<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2083Instruction</a> </div>
2084
2085<div class="doc_text">
2086
2087<h5>Syntax:</h5>
2088<pre>
2089 unreachable
2090</pre>
2091
2092<h5>Overview:</h5>
2093
2094<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2095instruction is used to inform the optimizer that a particular portion of the
2096code is not reachable. This can be used to indicate that the code after a
2097no-return function cannot be reached, and other facts.</p>
2098
2099<h5>Semantics:</h5>
2100
2101<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2102</div>
2103
2104
2105
2106<!-- ======================================================================= -->
2107<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
2108<div class="doc_text">
2109<p>Binary operators are used to do most of the computation in a
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2110program. They require two operands of the same type, execute an operation on them, and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2111produce a single value. The operands might represent
2112multiple 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]2113The result value has the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2114<p>There are several different binary operators:</p>
2115</div>
2116<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2117<div class="doc_subsubsection">
2118 <a name="i_add">'<tt>add</tt>' Instruction</a>
2119</div>
2120
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2121<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2122
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2123<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2124
2125<pre>
2126 &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]2127</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2128
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2129<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2130
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2131<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2132
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2133<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2134
2135<p>The two arguments to the '<tt>add</tt>' instruction must be <a
2136 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
2137 <a href="#t_vector">vector</a> values. Both arguments must have identical
2138 types.</p>
2139
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2140<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2141
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2142<p>The value produced is the integer or floating point sum of the two
2143operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2144
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2145<p>If an integer sum has unsigned overflow, the result returned is the
2146mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2147the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2148
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2149<p>Because LLVM integers use a two's complement representation, this
2150instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2151
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2152<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2153
2154<pre>
2155 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2156</pre>
2157</div>
2158<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2159<div class="doc_subsubsection">
2160 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2161</div>
2162
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2163<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2164
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2165<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2166
2167<pre>
2168 &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]2169</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2170
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2171<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2172
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2173<p>The '<tt>sub</tt>' instruction returns the difference of its two
2174operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2175
2176<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2177'<tt>neg</tt>' instruction present in most other intermediate
2178representations.</p>
2179
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2180<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2181
2182<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
2183 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2184 or <a href="#t_vector">vector</a> values. Both arguments must have identical
2185 types.</p>
2186
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2187<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2188
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2189<p>The value produced is the integer or floating point difference of
2190the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2191
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2192<p>If an integer difference has unsigned overflow, the result returned is the
2193mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2194the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2195
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2196<p>Because LLVM integers use a two's complement representation, this
2197instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2198
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2199<h5>Example:</h5>
2200<pre>
2201 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2202 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2203</pre>
2204</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2205
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2206<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2207<div class="doc_subsubsection">
2208 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2209</div>
2210
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2211<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2212
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2213<h5>Syntax:</h5>
2214<pre> &lt;result&gt; = mul &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2215</pre>
2216<h5>Overview:</h5>
2217<p>The '<tt>mul</tt>' instruction returns the product of its two
2218operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2219
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2220<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2221
2222<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
2223href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2224or <a href="#t_vector">vector</a> values. Both arguments must have identical
2225types.</p>
2226
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2227<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2228
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2229<p>The value produced is the integer or floating point product of the
2230two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2231
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2232<p>If the result of an integer multiplication has unsigned overflow,
2233the result returned is the mathematical result modulo
22342<sup>n</sup>, where n is the bit width of the result.</p>
2235<p>Because LLVM integers use a two's complement representation, and the
2236result is the same width as the operands, this instruction returns the
2237correct result for both signed and unsigned integers. If a full product
2238(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2239should be sign-extended or zero-extended as appropriate to the
2240width of the full product.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2241<h5>Example:</h5>
2242<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
2243</pre>
2244</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2245
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2246<!-- _______________________________________________________________________ -->
2247<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2248</a></div>
2249<div class="doc_text">
2250<h5>Syntax:</h5>
2251<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2252</pre>
2253<h5>Overview:</h5>
2254<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2255operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2256
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2257<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2258
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2259<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2260<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2261values. Both arguments must have identical types.</p>
2262
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2263<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2264
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2265<p>The value produced is the unsigned integer quotient of the two operands.</p>
2266<p>Note that unsigned integer division and signed integer division are distinct
2267operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2268<p>Division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2269<h5>Example:</h5>
2270<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2271</pre>
2272</div>
2273<!-- _______________________________________________________________________ -->
2274<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2275</a> </div>
2276<div class="doc_text">
2277<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2278<pre>
2279 &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]2280</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2281
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2282<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2283
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2284<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2285operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2286
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2287<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2288
2289<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2290<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2291values. Both arguments must have identical types.</p>
2292
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2293<h5>Semantics:</h5>
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2294<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]2295<p>Note that signed integer division and unsigned integer division are distinct
2296operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2297<p>Division by zero leads to undefined behavior. Overflow also leads to
2298undefined behavior; this is a rare case, but can occur, for example,
2299by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2300<h5>Example:</h5>
2301<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2302</pre>
2303</div>
2304<!-- _______________________________________________________________________ -->
2305<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2306Instruction</a> </div>
2307<div class="doc_text">
2308<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2309<pre>
2310 &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]2311</pre>
2312<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2313
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2314<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
2315operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2316
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2317<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2318
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2319<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2320<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2321of floating point values. Both arguments must have identical types.</p>
2322
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2323<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2324
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2325<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2326
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2327<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2328
2329<pre>
2330 &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]2331</pre>
2332</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2333
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2334<!-- _______________________________________________________________________ -->
2335<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2336</div>
2337<div class="doc_text">
2338<h5>Syntax:</h5>
2339<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2340</pre>
2341<h5>Overview:</h5>
2342<p>The '<tt>urem</tt>' instruction returns the remainder from the
2343unsigned division of its two arguments.</p>
2344<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2345<p>The two arguments to the '<tt>urem</tt>' instruction must be
2346<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2347values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2348<h5>Semantics:</h5>
2349<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2350This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2351<p>Note that unsigned integer remainder and signed integer remainder are
2352distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2353<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2354<h5>Example:</h5>
2355<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2356</pre>
2357
2358</div>
2359<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2360<div class="doc_subsubsection">
2361 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2362</div>
2363
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2364<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2365
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2366<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2367
2368<pre>
2369 &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]2370</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2371
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2372<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2373
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2374<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman3e3fd8c2007-11-05 23:35:22 +0000[diff] [blame]2375signed division of its two operands. This instruction can also take
2376<a href="#t_vector">vector</a> versions of the values in which case
2377the elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]2378
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2379<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2380
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2381<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2382<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2383values. Both arguments must have identical types.</p>
2384
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2385<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2386
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2387<p>This instruction returns the <i>remainder</i> of a division (where the result
2388has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2389operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2390a value. For more information about the difference, see <a
2391 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2392Math Forum</a>. For a table of how this is implemented in various languages,
2393please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
2394Wikipedia: modulo operation</a>.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2395<p>Note that signed integer remainder and unsigned integer remainder are
2396distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2397<p>Taking the remainder of a division by zero leads to undefined behavior.
2398Overflow also leads to undefined behavior; this is a rare case, but can occur,
2399for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2400(The remainder doesn't actually overflow, but this rule lets srem be
2401implemented using instructions that return both the result of the division
2402and the remainder.)</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2403<h5>Example:</h5>
2404<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2405</pre>
2406
2407</div>
2408<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2409<div class="doc_subsubsection">
2410 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2411
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2412<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2413
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2414<h5>Syntax:</h5>
2415<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2416</pre>
2417<h5>Overview:</h5>
2418<p>The '<tt>frem</tt>' instruction returns the remainder from the
2419division of its two operands.</p>
2420<h5>Arguments:</h5>
2421<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2422<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2423of floating point values. Both arguments must have identical types.</p>
2424
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2425<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2426
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2427<p>This instruction returns the <i>remainder</i> of a division.
2428The remainder has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2429
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2430<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2431
2432<pre>
2433 &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]2434</pre>
2435</div>
2436
2437<!-- ======================================================================= -->
2438<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2439Operations</a> </div>
2440<div class="doc_text">
2441<p>Bitwise binary operators are used to do various forms of
2442bit-twiddling in a program. They are generally very efficient
2443instructions and can commonly be strength reduced from other
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2444instructions. They require two operands of the same type, execute an operation on them,
2445and 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]2446</div>
2447
2448<!-- _______________________________________________________________________ -->
2449<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2450Instruction</a> </div>
2451<div class="doc_text">
2452<h5>Syntax:</h5>
2453<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2454</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2455
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2456<h5>Overview:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2457
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2458<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2459the left a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2460
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2461<h5>Arguments:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2462
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2463<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2464 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2465type. '<tt>var2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2466
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2467<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2468
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2469<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup> mod 2<sup>n</sup>,
2470where n is the width of the result. If <tt>var2</tt> is (statically or dynamically) negative or
2471equal 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]2472
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2473<h5>Example:</h5><pre>
2474 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2475 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2476 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2477 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2478</pre>
2479</div>
2480<!-- _______________________________________________________________________ -->
2481<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2482Instruction</a> </div>
2483<div class="doc_text">
2484<h5>Syntax:</h5>
2485<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2486</pre>
2487
2488<h5>Overview:</h5>
2489<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2490operand shifted to the right a specified number of bits with zero fill.</p>
2491
2492<h5>Arguments:</h5>
2493<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2494<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2495type. '<tt>var2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2496
2497<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2498
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2499<p>This instruction always performs a logical shift right operation. The most
2500significant bits of the result will be filled with zero bits after the
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2501shift. If <tt>var2</tt> is (statically or dynamically) equal to or larger than
2502the number of bits in <tt>var1</tt>, the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2503
2504<h5>Example:</h5>
2505<pre>
2506 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2507 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2508 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2509 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2510 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2511</pre>
2512</div>
2513
2514<!-- _______________________________________________________________________ -->
2515<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2516Instruction</a> </div>
2517<div class="doc_text">
2518
2519<h5>Syntax:</h5>
2520<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2521</pre>
2522
2523<h5>Overview:</h5>
2524<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2525operand shifted to the right a specified number of bits with sign extension.</p>
2526
2527<h5>Arguments:</h5>
2528<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2529<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2530type. '<tt>var2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2531
2532<h5>Semantics:</h5>
2533<p>This instruction always performs an arithmetic shift right operation,
2534The most significant bits of the result will be filled with the sign bit
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2535of <tt>var1</tt>. If <tt>var2</tt> is (statically or dynamically) equal to or
2536larger than the number of bits in <tt>var1</tt>, the result is undefined.
2537</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2538
2539<h5>Example:</h5>
2540<pre>
2541 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2542 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2543 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2544 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2545 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2546</pre>
2547</div>
2548
2549<!-- _______________________________________________________________________ -->
2550<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2551Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2552
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2553<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2554
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2555<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2556
2557<pre>
2558 &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]2559</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2560
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2561<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2562
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2563<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2564its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2565
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2566<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2567
2568<p>The two arguments to the '<tt>and</tt>' instruction must be
2569<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2570values. Both arguments must have identical types.</p>
2571
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2572<h5>Semantics:</h5>
2573<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
2574<p> </p>
2575<div style="align: center">
2576<table border="1" cellspacing="0" cellpadding="4">
2577 <tbody>
2578 <tr>
2579 <td>In0</td>
2580 <td>In1</td>
2581 <td>Out</td>
2582 </tr>
2583 <tr>
2584 <td>0</td>
2585 <td>0</td>
2586 <td>0</td>
2587 </tr>
2588 <tr>
2589 <td>0</td>
2590 <td>1</td>
2591 <td>0</td>
2592 </tr>
2593 <tr>
2594 <td>1</td>
2595 <td>0</td>
2596 <td>0</td>
2597 </tr>
2598 <tr>
2599 <td>1</td>
2600 <td>1</td>
2601 <td>1</td>
2602 </tr>
2603 </tbody>
2604</table>
2605</div>
2606<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2607<pre>
2608 &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]2609 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2610 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
2611</pre>
2612</div>
2613<!-- _______________________________________________________________________ -->
2614<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
2615<div class="doc_text">
2616<h5>Syntax:</h5>
2617<pre> &lt;result&gt; = or &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2618</pre>
2619<h5>Overview:</h5>
2620<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2621or of its two operands.</p>
2622<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2623
2624<p>The two arguments to the '<tt>or</tt>' instruction must be
2625<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2626values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2627<h5>Semantics:</h5>
2628<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
2629<p> </p>
2630<div style="align: center">
2631<table border="1" cellspacing="0" cellpadding="4">
2632 <tbody>
2633 <tr>
2634 <td>In0</td>
2635 <td>In1</td>
2636 <td>Out</td>
2637 </tr>
2638 <tr>
2639 <td>0</td>
2640 <td>0</td>
2641 <td>0</td>
2642 </tr>
2643 <tr>
2644 <td>0</td>
2645 <td>1</td>
2646 <td>1</td>
2647 </tr>
2648 <tr>
2649 <td>1</td>
2650 <td>0</td>
2651 <td>1</td>
2652 </tr>
2653 <tr>
2654 <td>1</td>
2655 <td>1</td>
2656 <td>1</td>
2657 </tr>
2658 </tbody>
2659</table>
2660</div>
2661<h5>Example:</h5>
2662<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2663 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2664 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
2665</pre>
2666</div>
2667<!-- _______________________________________________________________________ -->
2668<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2669Instruction</a> </div>
2670<div class="doc_text">
2671<h5>Syntax:</h5>
2672<pre> &lt;result&gt; = xor &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2673</pre>
2674<h5>Overview:</h5>
2675<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2676or of its two operands. The <tt>xor</tt> is used to implement the
2677"one's complement" operation, which is the "~" operator in C.</p>
2678<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2679<p>The two arguments to the '<tt>xor</tt>' instruction must be
2680<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2681values. Both arguments must have identical types.</p>
2682
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2683<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2684
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2685<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
2686<p> </p>
2687<div style="align: center">
2688<table border="1" cellspacing="0" cellpadding="4">
2689 <tbody>
2690 <tr>
2691 <td>In0</td>
2692 <td>In1</td>
2693 <td>Out</td>
2694 </tr>
2695 <tr>
2696 <td>0</td>
2697 <td>0</td>
2698 <td>0</td>
2699 </tr>
2700 <tr>
2701 <td>0</td>
2702 <td>1</td>
2703 <td>1</td>
2704 </tr>
2705 <tr>
2706 <td>1</td>
2707 <td>0</td>
2708 <td>1</td>
2709 </tr>
2710 <tr>
2711 <td>1</td>
2712 <td>1</td>
2713 <td>0</td>
2714 </tr>
2715 </tbody>
2716</table>
2717</div>
2718<p> </p>
2719<h5>Example:</h5>
2720<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2721 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2722 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2723 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
2724</pre>
2725</div>
2726
2727<!-- ======================================================================= -->
2728<div class="doc_subsection">
2729 <a name="vectorops">Vector Operations</a>
2730</div>
2731
2732<div class="doc_text">
2733
2734<p>LLVM supports several instructions to represent vector operations in a
2735target-independent manner. These instructions cover the element-access and
2736vector-specific operations needed to process vectors effectively. While LLVM
2737does directly support these vector operations, many sophisticated algorithms
2738will want to use target-specific intrinsics to take full advantage of a specific
2739target.</p>
2740
2741</div>
2742
2743<!-- _______________________________________________________________________ -->
2744<div class="doc_subsubsection">
2745 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2746</div>
2747
2748<div class="doc_text">
2749
2750<h5>Syntax:</h5>
2751
2752<pre>
2753 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
2754</pre>
2755
2756<h5>Overview:</h5>
2757
2758<p>
2759The '<tt>extractelement</tt>' instruction extracts a single scalar
2760element from a vector at a specified index.
2761</p>
2762
2763
2764<h5>Arguments:</h5>
2765
2766<p>
2767The first operand of an '<tt>extractelement</tt>' instruction is a
2768value of <a href="#t_vector">vector</a> type. The second operand is
2769an index indicating the position from which to extract the element.
2770The index may be a variable.</p>
2771
2772<h5>Semantics:</h5>
2773
2774<p>
2775The result is a scalar of the same type as the element type of
2776<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2777<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2778results are undefined.
2779</p>
2780
2781<h5>Example:</h5>
2782
2783<pre>
2784 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
2785</pre>
2786</div>
2787
2788
2789<!-- _______________________________________________________________________ -->
2790<div class="doc_subsubsection">
2791 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2792</div>
2793
2794<div class="doc_text">
2795
2796<h5>Syntax:</h5>
2797
2798<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]2799 &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]2800</pre>
2801
2802<h5>Overview:</h5>
2803
2804<p>
2805The '<tt>insertelement</tt>' instruction inserts a scalar
2806element into a vector at a specified index.
2807</p>
2808
2809
2810<h5>Arguments:</h5>
2811
2812<p>
2813The first operand of an '<tt>insertelement</tt>' instruction is a
2814value of <a href="#t_vector">vector</a> type. The second operand is a
2815scalar value whose type must equal the element type of the first
2816operand. The third operand is an index indicating the position at
2817which to insert the value. The index may be a variable.</p>
2818
2819<h5>Semantics:</h5>
2820
2821<p>
2822The result is a vector of the same type as <tt>val</tt>. Its
2823element values are those of <tt>val</tt> except at position
2824<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2825exceeds the length of <tt>val</tt>, the results are undefined.
2826</p>
2827
2828<h5>Example:</h5>
2829
2830<pre>
2831 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
2832</pre>
2833</div>
2834
2835<!-- _______________________________________________________________________ -->
2836<div class="doc_subsubsection">
2837 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2838</div>
2839
2840<div class="doc_text">
2841
2842<h5>Syntax:</h5>
2843
2844<pre>
2845 &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>
2846</pre>
2847
2848<h5>Overview:</h5>
2849
2850<p>
2851The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2852from two input vectors, returning a vector of the same type.
2853</p>
2854
2855<h5>Arguments:</h5>
2856
2857<p>
2858The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2859with types that match each other and types that match the result of the
2860instruction. The third argument is a shuffle mask, which has the same number
2861of elements as the other vector type, but whose element type is always 'i32'.
2862</p>
2863
2864<p>
2865The shuffle mask operand is required to be a constant vector with either
2866constant integer or undef values.
2867</p>
2868
2869<h5>Semantics:</h5>
2870
2871<p>
2872The elements of the two input vectors are numbered from left to right across
2873both of the vectors. The shuffle mask operand specifies, for each element of
2874the result vector, which element of the two input registers the result element
2875gets. The element selector may be undef (meaning "don't care") and the second
2876operand may be undef if performing a shuffle from only one vector.
2877</p>
2878
2879<h5>Example:</h5>
2880
2881<pre>
2882 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
2883 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
2884 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2885 &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.
2886</pre>
2887</div>
2888
2889
2890<!-- ======================================================================= -->
2891<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2892 <a name="aggregateops">Aggregate Operations</a>
2893</div>
2894
2895<div class="doc_text">
2896
2897<p>LLVM supports several instructions for working with aggregate values.
2898</p>
2899
2900</div>
2901
2902<!-- _______________________________________________________________________ -->
2903<div class="doc_subsubsection">
2904 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
2905</div>
2906
2907<div class="doc_text">
2908
2909<h5>Syntax:</h5>
2910
2911<pre>
2912 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
2913</pre>
2914
2915<h5>Overview:</h5>
2916
2917<p>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]2918The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
2919or array element from an aggregate value.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2920</p>
2921
2922
2923<h5>Arguments:</h5>
2924
2925<p>
2926The first operand of an '<tt>extractvalue</tt>' instruction is a
2927value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]2928type. The operands are constant indices to specify which value to extract
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]2929in a similar manner as indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2930'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2931</p>
2932
2933<h5>Semantics:</h5>
2934
2935<p>
2936The result is the value at the position in the aggregate specified by
2937the index operands.
2938</p>
2939
2940<h5>Example:</h5>
2941
2942<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]2943 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2944</pre>
2945</div>
2946
2947
2948<!-- _______________________________________________________________________ -->
2949<div class="doc_subsubsection">
2950 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
2951</div>
2952
2953<div class="doc_text">
2954
2955<h5>Syntax:</h5>
2956
2957<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]2958 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;val&gt;, &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2959</pre>
2960
2961<h5>Overview:</h5>
2962
2963<p>
2964The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]2965into a struct field or array element in an aggregate.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2966</p>
2967
2968
2969<h5>Arguments:</h5>
2970
2971<p>
2972The first operand of an '<tt>insertvalue</tt>' instruction is a
2973value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
2974The second operand is a first-class value to insert.
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]2975The following operands are constant indices
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]2976indicating the position at which to insert the value in a similar manner as
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]2977indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2978'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2979The value to insert must have the same type as the value identified
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]2980by the indices.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2981
2982<h5>Semantics:</h5>
2983
2984<p>
2985The result is an aggregate of the same type as <tt>val</tt>. Its
2986value is that of <tt>val</tt> except that the value at the position
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]2987specified by the indices is that of <tt>elt</tt>.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2988</p>
2989
2990<h5>Example:</h5>
2991
2992<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]2993 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]2994</pre>
2995</div>
2996
2997
2998<!-- ======================================================================= -->
2999<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3000 <a name="memoryops">Memory Access and Addressing Operations</a>
3001</div>
3002
3003<div class="doc_text">
3004
3005<p>A key design point of an SSA-based representation is how it
3006represents memory. In LLVM, no memory locations are in SSA form, which
3007makes things very simple. This section describes how to read, write,
3008allocate, and free memory in LLVM.</p>
3009
3010</div>
3011
3012<!-- _______________________________________________________________________ -->
3013<div class="doc_subsubsection">
3014 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3015</div>
3016
3017<div class="doc_text">
3018
3019<h5>Syntax:</h5>
3020
3021<pre>
3022 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3023</pre>
3024
3025<h5>Overview:</h5>
3026
3027<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3028heap and returns a pointer to it. The object is always allocated in the generic
3029address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3030
3031<h5>Arguments:</h5>
3032
3033<p>The '<tt>malloc</tt>' instruction allocates
3034<tt>sizeof(&lt;type&gt;)*NumElements</tt>
3035bytes of memory from the operating system and returns a pointer of the
3036appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3037number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3038If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3039be aligned to at least that boundary. If not specified, or if zero, the target can
3040choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3041
3042<p>'<tt>type</tt>' must be a sized type.</p>
3043
3044<h5>Semantics:</h5>
3045
3046<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3047a pointer is returned. The result of a zero byte allocattion is undefined. The
3048result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3049
3050<h5>Example:</h5>
3051
3052<pre>
3053 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
3054
3055 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3056 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3057 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3058 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3059 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3060</pre>
3061</div>
3062
3063<!-- _______________________________________________________________________ -->
3064<div class="doc_subsubsection">
3065 <a name="i_free">'<tt>free</tt>' Instruction</a>
3066</div>
3067
3068<div class="doc_text">
3069
3070<h5>Syntax:</h5>
3071
3072<pre>
3073 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
3074</pre>
3075
3076<h5>Overview:</h5>
3077
3078<p>The '<tt>free</tt>' instruction returns memory back to the unused
3079memory heap to be reallocated in the future.</p>
3080
3081<h5>Arguments:</h5>
3082
3083<p>'<tt>value</tt>' shall be a pointer value that points to a value
3084that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3085instruction.</p>
3086
3087<h5>Semantics:</h5>
3088
3089<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner329d6532008-04-19 22:41:32 +0000[diff] [blame]3090after this instruction executes. If the pointer is null, the operation
3091is a noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3092
3093<h5>Example:</h5>
3094
3095<pre>
3096 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
3097 free [4 x i8]* %array
3098</pre>
3099</div>
3100
3101<!-- _______________________________________________________________________ -->
3102<div class="doc_subsubsection">
3103 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3104</div>
3105
3106<div class="doc_text">
3107
3108<h5>Syntax:</h5>
3109
3110<pre>
3111 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3112</pre>
3113
3114<h5>Overview:</h5>
3115
3116<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3117currently executing function, to be automatically released when this function
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3118returns to its caller. The object is always allocated in the generic address
3119space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3120
3121<h5>Arguments:</h5>
3122
3123<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
3124bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3125appropriate type to the program. If "NumElements" is specified, it is the
3126number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3127If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3128to be aligned to at least that boundary. If not specified, or if zero, the target
3129can choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3130
3131<p>'<tt>type</tt>' may be any sized type.</p>
3132
3133<h5>Semantics:</h5>
3134
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3135<p>Memory is allocated; a pointer is returned. The operation is undefiend if
3136there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3137memory is automatically released when the function returns. The '<tt>alloca</tt>'
3138instruction is commonly used to represent automatic variables that must
3139have an address available. When the function returns (either with the <tt><a
3140 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]3141instructions), the memory is reclaimed. Allocating zero bytes
3142is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3143
3144<h5>Example:</h5>
3145
3146<pre>
3147 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3148 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3149 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3150 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
3151</pre>
3152</div>
3153
3154<!-- _______________________________________________________________________ -->
3155<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3156Instruction</a> </div>
3157<div class="doc_text">
3158<h5>Syntax:</h5>
3159<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>
3160<h5>Overview:</h5>
3161<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
3162<h5>Arguments:</h5>
3163<p>The argument to the '<tt>load</tt>' instruction specifies the memory
3164address from which to load. The pointer must point to a <a
3165 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3166marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
3167the number or order of execution of this <tt>load</tt> with other
3168volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3169instructions. </p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3170<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3171The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3172(that is, the alignment of the memory address). A value of 0 or an
3173omitted "align" argument means that the operation has the preferential
3174alignment for the target. It is the responsibility of the code emitter
3175to ensure that the alignment information is correct. Overestimating
3176the alignment results in an undefined behavior. Underestimating the
3177alignment may produce less efficient code. An alignment of 1 is always
3178safe.
3179</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3180<h5>Semantics:</h5>
3181<p>The location of memory pointed to is loaded.</p>
3182<h5>Examples:</h5>
3183<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3184 <a
3185 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3186 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3187</pre>
3188</div>
3189<!-- _______________________________________________________________________ -->
3190<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3191Instruction</a> </div>
3192<div class="doc_text">
3193<h5>Syntax:</h5>
3194<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3195 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3196</pre>
3197<h5>Overview:</h5>
3198<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
3199<h5>Arguments:</h5>
3200<p>There are two arguments to the '<tt>store</tt>' instruction: a value
3201to 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]3202operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3203of the '<tt>&lt;value&gt;</tt>'
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3204operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
3205optimizer is not allowed to modify the number or order of execution of
3206this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3207 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3208<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3209The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3210(that is, the alignment of the memory address). A value of 0 or an
3211omitted "align" argument means that the operation has the preferential
3212alignment for the target. It is the responsibility of the code emitter
3213to ensure that the alignment information is correct. Overestimating
3214the alignment results in an undefined behavior. Underestimating the
3215alignment may produce less efficient code. An alignment of 1 is always
3216safe.
3217</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3218<h5>Semantics:</h5>
3219<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
3220at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
3221<h5>Example:</h5>
3222<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3223 store i32 3, i32* %ptr <i>; yields {void}</i>
3224 %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]3225</pre>
3226</div>
3227
3228<!-- _______________________________________________________________________ -->
3229<div class="doc_subsubsection">
3230 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3231</div>
3232
3233<div class="doc_text">
3234<h5>Syntax:</h5>
3235<pre>
3236 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
3237</pre>
3238
3239<h5>Overview:</h5>
3240
3241<p>
3242The '<tt>getelementptr</tt>' instruction is used to get the address of a
3243subelement of an aggregate data structure.</p>
3244
3245<h5>Arguments:</h5>
3246
3247<p>This instruction takes a list of integer operands that indicate what
3248elements of the aggregate object to index to. The actual types of the arguments
3249provided depend on the type of the first pointer argument. The
3250'<tt>getelementptr</tt>' instruction is used to index down through the type
3251levels of a structure or to a specific index in an array. When indexing into a
3252structure, only <tt>i32</tt> integer constants are allowed. When indexing
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]3253into an array or pointer, only integers of 32 or 64 bits are allowed; 32-bit
3254values will be sign extended to 64-bits if required.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3255
3256<p>For example, let's consider a C code fragment and how it gets
3257compiled to LLVM:</p>
3258
3259<div class="doc_code">
3260<pre>
3261struct RT {
3262 char A;
3263 int B[10][20];
3264 char C;
3265};
3266struct ST {
3267 int X;
3268 double Y;
3269 struct RT Z;
3270};
3271
3272int *foo(struct ST *s) {
3273 return &amp;s[1].Z.B[5][13];
3274}
3275</pre>
3276</div>
3277
3278<p>The LLVM code generated by the GCC frontend is:</p>
3279
3280<div class="doc_code">
3281<pre>
3282%RT = type { i8 , [10 x [20 x i32]], i8 }
3283%ST = type { i32, double, %RT }
3284
3285define i32* %foo(%ST* %s) {
3286entry:
3287 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3288 ret i32* %reg
3289}
3290</pre>
3291</div>
3292
3293<h5>Semantics:</h5>
3294
3295<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
3296on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
3297and <a href="#t_array">array</a> types can use a 32-bit or 64-bit
3298<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]3299to 64-bits. <a href="#t_struct">Structure</a> and <a href="#t_pstruct">packed
3300structure</a> types require <tt>i32</tt> <b>constants</b>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3301
3302<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
3303type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3304}</tt>' type, a structure. The second index indexes into the third element of
3305the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3306i8 }</tt>' type, another structure. The third index indexes into the second
3307element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3308array. The two dimensions of the array are subscripted into, yielding an
3309'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3310to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
3311
3312<p>Note that it is perfectly legal to index partially through a
3313structure, returning a pointer to an inner element. Because of this,
3314the LLVM code for the given testcase is equivalent to:</p>
3315
3316<pre>
3317 define i32* %foo(%ST* %s) {
3318 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3319 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3320 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3321 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3322 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3323 ret i32* %t5
3324 }
3325</pre>
3326
3327<p>Note that it is undefined to access an array out of bounds: array and
3328pointer indexes must always be within the defined bounds of the array type.
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]3329The one exception for this rule is zero length arrays. These arrays are
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3330defined to be accessible as variable length arrays, which requires access
3331beyond the zero'th element.</p>
3332
3333<p>The getelementptr instruction is often confusing. For some more insight
3334into how it works, see <a href="GetElementPtr.html">the getelementptr
3335FAQ</a>.</p>
3336
3337<h5>Example:</h5>
3338
3339<pre>
3340 <i>; yields [12 x i8]*:aptr</i>
3341 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
3342</pre>
3343</div>
3344
3345<!-- ======================================================================= -->
3346<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3347</div>
3348<div class="doc_text">
3349<p>The instructions in this category are the conversion instructions (casting)
3350which all take a single operand and a type. They perform various bit conversions
3351on the operand.</p>
3352</div>
3353
3354<!-- _______________________________________________________________________ -->
3355<div class="doc_subsubsection">
3356 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3357</div>
3358<div class="doc_text">
3359
3360<h5>Syntax:</h5>
3361<pre>
3362 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3363</pre>
3364
3365<h5>Overview:</h5>
3366<p>
3367The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3368</p>
3369
3370<h5>Arguments:</h5>
3371<p>
3372The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3373be an <a href="#t_integer">integer</a> type, and a type that specifies the size
3374and type of the result, which must be an <a href="#t_integer">integer</a>
3375type. The bit size of <tt>value</tt> must be larger than the bit size of
3376<tt>ty2</tt>. Equal sized types are not allowed.</p>
3377
3378<h5>Semantics:</h5>
3379<p>
3380The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
3381and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3382larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3383It will always truncate bits.</p>
3384
3385<h5>Example:</h5>
3386<pre>
3387 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3388 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3389 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
3390</pre>
3391</div>
3392
3393<!-- _______________________________________________________________________ -->
3394<div class="doc_subsubsection">
3395 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3396</div>
3397<div class="doc_text">
3398
3399<h5>Syntax:</h5>
3400<pre>
3401 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3402</pre>
3403
3404<h5>Overview:</h5>
3405<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3406<tt>ty2</tt>.</p>
3407
3408
3409<h5>Arguments:</h5>
3410<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
3411<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3412also be of <a href="#t_integer">integer</a> type. The bit size of the
3413<tt>value</tt> must be smaller than the bit size of the destination type,
3414<tt>ty2</tt>.</p>
3415
3416<h5>Semantics:</h5>
3417<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
3418bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
3419
3420<p>When zero extending from i1, the result will always be either 0 or 1.</p>
3421
3422<h5>Example:</h5>
3423<pre>
3424 %X = zext i32 257 to i64 <i>; yields i64:257</i>
3425 %Y = zext i1 true to i32 <i>; yields i32:1</i>
3426</pre>
3427</div>
3428
3429<!-- _______________________________________________________________________ -->
3430<div class="doc_subsubsection">
3431 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3432</div>
3433<div class="doc_text">
3434
3435<h5>Syntax:</h5>
3436<pre>
3437 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3438</pre>
3439
3440<h5>Overview:</h5>
3441<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3442
3443<h5>Arguments:</h5>
3444<p>
3445The '<tt>sext</tt>' instruction takes a value to cast, which must be of
3446<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3447also be of <a href="#t_integer">integer</a> type. The bit size of the
3448<tt>value</tt> must be smaller than the bit size of the destination type,
3449<tt>ty2</tt>.</p>
3450
3451<h5>Semantics:</h5>
3452<p>
3453The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3454bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
3455the type <tt>ty2</tt>.</p>
3456
3457<p>When sign extending from i1, the extension always results in -1 or 0.</p>
3458
3459<h5>Example:</h5>
3460<pre>
3461 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
3462 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
3463</pre>
3464</div>
3465
3466<!-- _______________________________________________________________________ -->
3467<div class="doc_subsubsection">
3468 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3469</div>
3470
3471<div class="doc_text">
3472
3473<h5>Syntax:</h5>
3474
3475<pre>
3476 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3477</pre>
3478
3479<h5>Overview:</h5>
3480<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3481<tt>ty2</tt>.</p>
3482
3483
3484<h5>Arguments:</h5>
3485<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3486 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3487cast it to. The size of <tt>value</tt> must be larger than the size of
3488<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3489<i>no-op cast</i>.</p>
3490
3491<h5>Semantics:</h5>
3492<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3493<a href="#t_floating">floating point</a> type to a smaller
3494<a href="#t_floating">floating point</a> type. If the value cannot fit within
3495the destination type, <tt>ty2</tt>, then the results are undefined.</p>
3496
3497<h5>Example:</h5>
3498<pre>
3499 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3500 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3501</pre>
3502</div>
3503
3504<!-- _______________________________________________________________________ -->
3505<div class="doc_subsubsection">
3506 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3507</div>
3508<div class="doc_text">
3509
3510<h5>Syntax:</h5>
3511<pre>
3512 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3513</pre>
3514
3515<h5>Overview:</h5>
3516<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3517floating point value.</p>
3518
3519<h5>Arguments:</h5>
3520<p>The '<tt>fpext</tt>' instruction takes a
3521<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
3522and a <a href="#t_floating">floating point</a> type to cast it to. The source
3523type must be smaller than the destination type.</p>
3524
3525<h5>Semantics:</h5>
3526<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
3527<a href="#t_floating">floating point</a> type to a larger
3528<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
3529used to make a <i>no-op cast</i> because it always changes bits. Use
3530<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
3531
3532<h5>Example:</h5>
3533<pre>
3534 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3535 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3536</pre>
3537</div>
3538
3539<!-- _______________________________________________________________________ -->
3540<div class="doc_subsubsection">
3541 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
3542</div>
3543<div class="doc_text">
3544
3545<h5>Syntax:</h5>
3546<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3547 &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]3548</pre>
3549
3550<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3551<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3552unsigned integer equivalent of type <tt>ty2</tt>.
3553</p>
3554
3555<h5>Arguments:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3556<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]3557scalar or vector <a href="#t_floating">floating point</a> value, and a type
3558to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3559type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3560vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3561
3562<h5>Semantics:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3563<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3564<a href="#t_floating">floating point</a> operand into the nearest (rounding
3565towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3566the results are undefined.</p>
3567
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3568<h5>Example:</h5>
3569<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3570 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3571 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3572 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3573</pre>
3574</div>
3575
3576<!-- _______________________________________________________________________ -->
3577<div class="doc_subsubsection">
3578 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
3579</div>
3580<div class="doc_text">
3581
3582<h5>Syntax:</h5>
3583<pre>
3584 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3585</pre>
3586
3587<h5>Overview:</h5>
3588<p>The '<tt>fptosi</tt>' instruction converts
3589<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
3590</p>
3591
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3592<h5>Arguments:</h5>
3593<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]3594scalar or vector <a href="#t_floating">floating point</a> value, and a type
3595to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3596type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3597vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3598
3599<h5>Semantics:</h5>
3600<p>The '<tt>fptosi</tt>' instruction converts its
3601<a href="#t_floating">floating point</a> operand into the nearest (rounding
3602towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3603the results are undefined.</p>
3604
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3605<h5>Example:</h5>
3606<pre>
3607 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3608 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3609 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
3610</pre>
3611</div>
3612
3613<!-- _______________________________________________________________________ -->
3614<div class="doc_subsubsection">
3615 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
3616</div>
3617<div class="doc_text">
3618
3619<h5>Syntax:</h5>
3620<pre>
3621 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3622</pre>
3623
3624<h5>Overview:</h5>
3625<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
3626integer and converts that value to the <tt>ty2</tt> type.</p>
3627
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3628<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3629<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3630scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3631to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3632type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3633floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3634
3635<h5>Semantics:</h5>
3636<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
3637integer quantity and converts it to the corresponding floating point value. If
3638the value cannot fit in the floating point value, the results are undefined.</p>
3639
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3640<h5>Example:</h5>
3641<pre>
3642 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
3643 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
3644</pre>
3645</div>
3646
3647<!-- _______________________________________________________________________ -->
3648<div class="doc_subsubsection">
3649 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
3650</div>
3651<div class="doc_text">
3652
3653<h5>Syntax:</h5>
3654<pre>
3655 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3656</pre>
3657
3658<h5>Overview:</h5>
3659<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
3660integer and converts that value to the <tt>ty2</tt> type.</p>
3661
3662<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3663<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3664scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3665to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3666type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3667floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3668
3669<h5>Semantics:</h5>
3670<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
3671integer quantity and converts it to the corresponding floating point value. If
3672the value cannot fit in the floating point value, the results are undefined.</p>
3673
3674<h5>Example:</h5>
3675<pre>
3676 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
3677 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
3678</pre>
3679</div>
3680
3681<!-- _______________________________________________________________________ -->
3682<div class="doc_subsubsection">
3683 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3684</div>
3685<div class="doc_text">
3686
3687<h5>Syntax:</h5>
3688<pre>
3689 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3690</pre>
3691
3692<h5>Overview:</h5>
3693<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3694the integer type <tt>ty2</tt>.</p>
3695
3696<h5>Arguments:</h5>
3697<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3698must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
3699<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3700
3701<h5>Semantics:</h5>
3702<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3703<tt>ty2</tt> by interpreting the pointer value as an integer and either
3704truncating or zero extending that value to the size of the integer type. If
3705<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3706<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3707are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3708change.</p>
3709
3710<h5>Example:</h5>
3711<pre>
3712 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3713 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
3714</pre>
3715</div>
3716
3717<!-- _______________________________________________________________________ -->
3718<div class="doc_subsubsection">
3719 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3720</div>
3721<div class="doc_text">
3722
3723<h5>Syntax:</h5>
3724<pre>
3725 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3726</pre>
3727
3728<h5>Overview:</h5>
3729<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3730a pointer type, <tt>ty2</tt>.</p>
3731
3732<h5>Arguments:</h5>
3733<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
3734value to cast, and a type to cast it to, which must be a
3735<a href="#t_pointer">pointer</a> type.
3736
3737<h5>Semantics:</h5>
3738<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3739<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3740the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3741size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3742the size of a pointer then a zero extension is done. If they are the same size,
3743nothing is done (<i>no-op cast</i>).</p>
3744
3745<h5>Example:</h5>
3746<pre>
3747 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3748 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3749 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
3750</pre>
3751</div>
3752
3753<!-- _______________________________________________________________________ -->
3754<div class="doc_subsubsection">
3755 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
3756</div>
3757<div class="doc_text">
3758
3759<h5>Syntax:</h5>
3760<pre>
3761 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3762</pre>
3763
3764<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3765
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3766<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
3767<tt>ty2</tt> without changing any bits.</p>
3768
3769<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3770
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3771<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
3772a first class value, and a type to cast it to, which must also be a <a
3773 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
3774and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3775type is a pointer, the destination type must also be a pointer. This
3776instruction supports bitwise conversion of vectors to integers and to vectors
3777of other types (as long as they have the same size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3778
3779<h5>Semantics:</h5>
3780<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
3781<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3782this conversion. The conversion is done as if the <tt>value</tt> had been
3783stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3784converted to other pointer types with this instruction. To convert pointers to
3785other types, use the <a href="#i_inttoptr">inttoptr</a> or
3786<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
3787
3788<h5>Example:</h5>
3789<pre>
3790 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
3791 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3792 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
3793</pre>
3794</div>
3795
3796<!-- ======================================================================= -->
3797<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3798<div class="doc_text">
3799<p>The instructions in this category are the "miscellaneous"
3800instructions, which defy better classification.</p>
3801</div>
3802
3803<!-- _______________________________________________________________________ -->
3804<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3805</div>
3806<div class="doc_text">
3807<h5>Syntax:</h5>
3808<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
3809</pre>
3810<h5>Overview:</h5>
3811<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3812of its two integer or pointer operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3813<h5>Arguments:</h5>
3814<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
3815the condition code indicating the kind of comparison to perform. It is not
3816a value, just a keyword. The possible condition code are:
3817<ol>
3818 <li><tt>eq</tt>: equal</li>
3819 <li><tt>ne</tt>: not equal </li>
3820 <li><tt>ugt</tt>: unsigned greater than</li>
3821 <li><tt>uge</tt>: unsigned greater or equal</li>
3822 <li><tt>ult</tt>: unsigned less than</li>
3823 <li><tt>ule</tt>: unsigned less or equal</li>
3824 <li><tt>sgt</tt>: signed greater than</li>
3825 <li><tt>sge</tt>: signed greater or equal</li>
3826 <li><tt>slt</tt>: signed less than</li>
3827 <li><tt>sle</tt>: signed less or equal</li>
3828</ol>
3829<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
3830<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
3831<h5>Semantics:</h5>
3832<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3833the condition code given as <tt>cond</tt>. The comparison performed always
3834yields a <a href="#t_primitive">i1</a> result, as follows:
3835<ol>
3836 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3837 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3838 </li>
3839 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3840 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3841 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3842 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3843 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3844 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3845 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3846 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3847 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3848 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3849 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3850 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3851 <li><tt>sge</tt>: interprets the operands as signed values and yields
3852 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3853 <li><tt>slt</tt>: interprets the operands as signed values and yields
3854 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3855 <li><tt>sle</tt>: interprets the operands as signed values and yields
3856 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3857</ol>
3858<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
3859values are compared as if they were integers.</p>
3860
3861<h5>Example:</h5>
3862<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3863 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3864 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3865 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3866 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3867 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
3868</pre>
3869</div>
3870
3871<!-- _______________________________________________________________________ -->
3872<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3873</div>
3874<div class="doc_text">
3875<h5>Syntax:</h5>
3876<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
3877</pre>
3878<h5>Overview:</h5>
3879<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3880of its floating point operands.</p>
3881<h5>Arguments:</h5>
3882<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
3883the condition code indicating the kind of comparison to perform. It is not
3884a value, just a keyword. The possible condition code are:
3885<ol>
3886 <li><tt>false</tt>: no comparison, always returns false</li>
3887 <li><tt>oeq</tt>: ordered and equal</li>
3888 <li><tt>ogt</tt>: ordered and greater than </li>
3889 <li><tt>oge</tt>: ordered and greater than or equal</li>
3890 <li><tt>olt</tt>: ordered and less than </li>
3891 <li><tt>ole</tt>: ordered and less than or equal</li>
3892 <li><tt>one</tt>: ordered and not equal</li>
3893 <li><tt>ord</tt>: ordered (no nans)</li>
3894 <li><tt>ueq</tt>: unordered or equal</li>
3895 <li><tt>ugt</tt>: unordered or greater than </li>
3896 <li><tt>uge</tt>: unordered or greater than or equal</li>
3897 <li><tt>ult</tt>: unordered or less than </li>
3898 <li><tt>ule</tt>: unordered or less than or equal</li>
3899 <li><tt>une</tt>: unordered or not equal</li>
3900 <li><tt>uno</tt>: unordered (either nans)</li>
3901 <li><tt>true</tt>: no comparison, always returns true</li>
3902</ol>
3903<p><i>Ordered</i> means that neither operand is a QNAN while
3904<i>unordered</i> means that either operand may be a QNAN.</p>
3905<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3906<a href="#t_floating">floating point</a> typed. They must have identical
3907types.</p>
3908<h5>Semantics:</h5>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]3909<p>The '<tt>fcmp</tt>' instruction compares <tt>var1</tt> and <tt>var2</tt>
3910according to the condition code given as <tt>cond</tt>. The comparison performed
3911always yields a <a href="#t_primitive">i1</a> result, as follows:
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3912<ol>
3913 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
3914 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
3915 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
3916 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
3917 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
3918 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
3919 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3920 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
3921 <tt>var1</tt> is less than <tt>var2</tt>.</li>
3922 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
3923 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3924 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
3925 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
3926 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3927 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
3928 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
3929 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
3930 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3931 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
3932 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3933 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
3934 <tt>var1</tt> is less than <tt>var2</tt>.</li>
3935 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
3936 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3937 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
3938 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
3939 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
3940 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3941</ol>
3942
3943<h5>Example:</h5>
3944<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3945 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3946 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3947 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3948</pre>
3949</div>
3950
3951<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]3952<div class="doc_subsubsection">
3953 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
3954</div>
3955<div class="doc_text">
3956<h5>Syntax:</h5>
3957<pre> &lt;result&gt; = vicmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
3958</pre>
3959<h5>Overview:</h5>
3960<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
3961element-wise comparison of its two integer vector operands.</p>
3962<h5>Arguments:</h5>
3963<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
3964the condition code indicating the kind of comparison to perform. It is not
3965a value, just a keyword. The possible condition code are:
3966<ol>
3967 <li><tt>eq</tt>: equal</li>
3968 <li><tt>ne</tt>: not equal </li>
3969 <li><tt>ugt</tt>: unsigned greater than</li>
3970 <li><tt>uge</tt>: unsigned greater or equal</li>
3971 <li><tt>ult</tt>: unsigned less than</li>
3972 <li><tt>ule</tt>: unsigned less or equal</li>
3973 <li><tt>sgt</tt>: signed greater than</li>
3974 <li><tt>sge</tt>: signed greater or equal</li>
3975 <li><tt>slt</tt>: signed less than</li>
3976 <li><tt>sle</tt>: signed less or equal</li>
3977</ol>
3978<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
3979<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
3980<h5>Semantics:</h5>
3981<p>The '<tt>vicmp</tt>' instruction compares <tt>var1</tt> and <tt>var2</tt>
3982according to the condition code given as <tt>cond</tt>. The comparison yields a
3983<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
3984identical type as the values being compared. The most significant bit in each
3985element is 1 if the element-wise comparison evaluates to true, and is 0
3986otherwise. All other bits of the result are undefined. The condition codes
3987are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
3988instruction</a>.
3989
3990<h5>Example:</h5>
3991<pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3992 &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>
3993 &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]3994</pre>
3995</div>
3996
3997<!-- _______________________________________________________________________ -->
3998<div class="doc_subsubsection">
3999 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
4000</div>
4001<div class="doc_text">
4002<h5>Syntax:</h5>
4003<pre> &lt;result&gt; = vfcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt;</pre>
4004<h5>Overview:</h5>
4005<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
4006element-wise comparison of its two floating point vector operands. The output
4007elements have the same width as the input elements.</p>
4008<h5>Arguments:</h5>
4009<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
4010the condition code indicating the kind of comparison to perform. It is not
4011a value, just a keyword. The possible condition code are:
4012<ol>
4013 <li><tt>false</tt>: no comparison, always returns false</li>
4014 <li><tt>oeq</tt>: ordered and equal</li>
4015 <li><tt>ogt</tt>: ordered and greater than </li>
4016 <li><tt>oge</tt>: ordered and greater than or equal</li>
4017 <li><tt>olt</tt>: ordered and less than </li>
4018 <li><tt>ole</tt>: ordered and less than or equal</li>
4019 <li><tt>one</tt>: ordered and not equal</li>
4020 <li><tt>ord</tt>: ordered (no nans)</li>
4021 <li><tt>ueq</tt>: unordered or equal</li>
4022 <li><tt>ugt</tt>: unordered or greater than </li>
4023 <li><tt>uge</tt>: unordered or greater than or equal</li>
4024 <li><tt>ult</tt>: unordered or less than </li>
4025 <li><tt>ule</tt>: unordered or less than or equal</li>
4026 <li><tt>une</tt>: unordered or not equal</li>
4027 <li><tt>uno</tt>: unordered (either nans)</li>
4028 <li><tt>true</tt>: no comparison, always returns true</li>
4029</ol>
4030<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4031<a href="#t_floating">floating point</a> typed. They must also be identical
4032types.</p>
4033<h5>Semantics:</h5>
4034<p>The '<tt>vfcmp</tt>' instruction compares <tt>var1</tt> and <tt>var2</tt>
4035according to the condition code given as <tt>cond</tt>. The comparison yields a
4036<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4037an identical number of elements as the values being compared, and each element
4038having identical with to the width of the floating point elements. The most
4039significant bit in each element is 1 if the element-wise comparison evaluates to
4040true, and is 0 otherwise. All other bits of the result are undefined. The
4041condition codes are evaluated identically to the
4042<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.
4043
4044<h5>Example:</h5>
4045<pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4046 &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>
4047 &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]4048</pre>
4049</div>
4050
4051<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4052<div class="doc_subsubsection">
4053 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4054</div>
4055
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4056<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4057
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4058<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4059
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4060<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4061<h5>Overview:</h5>
4062<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4063the SSA graph representing the function.</p>
4064<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4065
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4066<p>The type of the incoming values is specified with the first type
4067field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4068as arguments, with one pair for each predecessor basic block of the
4069current block. Only values of <a href="#t_firstclass">first class</a>
4070type may be used as the value arguments to the PHI node. Only labels
4071may be used as the label arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4072
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4073<p>There must be no non-phi instructions between the start of a basic
4074block and the PHI instructions: i.e. PHI instructions must be first in
4075a basic block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4076
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4077<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4078
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4079<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4080specified by the pair corresponding to the predecessor basic block that executed
4081just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4082
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4083<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4084<pre>
4085Loop: ; Infinite loop that counts from 0 on up...
4086 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4087 %nextindvar = add i32 %indvar, 1
4088 br label %Loop
4089</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4090</div>
4091
4092<!-- _______________________________________________________________________ -->
4093<div class="doc_subsubsection">
4094 <a name="i_select">'<tt>select</tt>' Instruction</a>
4095</div>
4096
4097<div class="doc_text">
4098
4099<h5>Syntax:</h5>
4100
4101<pre>
4102 &lt;result&gt; = select i1 &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
4103</pre>
4104
4105<h5>Overview:</h5>
4106
4107<p>
4108The '<tt>select</tt>' instruction is used to choose one value based on a
4109condition, without branching.
4110</p>
4111
4112
4113<h5>Arguments:</h5>
4114
4115<p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4116The '<tt>select</tt>' instruction requires an 'i1' value indicating the
4117condition, and two values of the same <a href="#t_firstclass">first class</a>
4118type. If the val1/val2 are vectors, the entire vectors are selected, not
4119individual elements.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4120</p>
4121
4122<h5>Semantics:</h5>
4123
4124<p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4125If the i1 condition evaluates is 1, the instruction returns the first
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4126value argument; otherwise, it returns the second value argument.
4127</p>
4128
4129<h5>Example:</h5>
4130
4131<pre>
4132 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4133</pre>
4134</div>
4135
4136
4137<!-- _______________________________________________________________________ -->
4138<div class="doc_subsubsection">
4139 <a name="i_call">'<tt>call</tt>' Instruction</a>
4140</div>
4141
4142<div class="doc_text">
4143
4144<h5>Syntax:</h5>
4145<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4146 &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]4147</pre>
4148
4149<h5>Overview:</h5>
4150
4151<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4152
4153<h5>Arguments:</h5>
4154
4155<p>This instruction requires several arguments:</p>
4156
4157<ol>
4158 <li>
4159 <p>The optional "tail" marker indicates whether the callee function accesses
4160 any allocas or varargs in the caller. If the "tail" marker is present, the
4161 function call is eligible for tail call optimization. Note that calls may
4162 be marked "tail" even if they do not occur before a <a
4163 href="#i_ret"><tt>ret</tt></a> instruction.
4164 </li>
4165 <li>
4166 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
4167 convention</a> the call should use. If none is specified, the call defaults
4168 to using C calling conventions.
4169 </li>
4170 <li>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4171 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4172 the type of the return value. Functions that return no value are marked
4173 <tt><a href="#t_void">void</a></tt>.</p>
4174 </li>
4175 <li>
4176 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4177 value being invoked. The argument types must match the types implied by
4178 this signature. This type can be omitted if the function is not varargs
4179 and if the function type does not return a pointer to a function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4180 </li>
4181 <li>
4182 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4183 be invoked. In most cases, this is a direct function invocation, but
4184 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4185 to function value.</p>
4186 </li>
4187 <li>
4188 <p>'<tt>function args</tt>': argument list whose types match the
4189 function signature argument types. All arguments must be of
4190 <a href="#t_firstclass">first class</a> type. If the function signature
4191 indicates the function accepts a variable number of arguments, the extra
4192 arguments can be specified.</p>
4193 </li>
4194</ol>
4195
4196<h5>Semantics:</h5>
4197
4198<p>The '<tt>call</tt>' instruction is used to cause control flow to
4199transfer to a specified function, with its incoming arguments bound to
4200the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4201instruction in the called function, control flow continues with the
4202instruction after the function call, and the return value of the
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4203function is bound to the result argument. If the callee returns multiple
4204values then the return values of the function are only accessible through
4205the '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4206
4207<h5>Example:</h5>
4208
4209<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4210 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4211 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4212 %X = tail call i32 @foo() <i>; yields i32</i>
4213 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4214 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4215
4216 %struct.A = type { i32, i8 }
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4217 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
4218 %gr = getresult %struct.A %r, 0 <i>; yields i32</i>
4219 %gr1 = getresult %struct.A %r, 1 <i>; yields i8</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4220</pre>
4221
4222</div>
4223
4224<!-- _______________________________________________________________________ -->
4225<div class="doc_subsubsection">
4226 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4227</div>
4228
4229<div class="doc_text">
4230
4231<h5>Syntax:</h5>
4232
4233<pre>
4234 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4235</pre>
4236
4237<h5>Overview:</h5>
4238
4239<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
4240the "variable argument" area of a function call. It is used to implement the
4241<tt>va_arg</tt> macro in C.</p>
4242
4243<h5>Arguments:</h5>
4244
4245<p>This instruction takes a <tt>va_list*</tt> value and the type of
4246the argument. It returns a value of the specified argument type and
4247increments the <tt>va_list</tt> to point to the next argument. The
4248actual type of <tt>va_list</tt> is target specific.</p>
4249
4250<h5>Semantics:</h5>
4251
4252<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4253type from the specified <tt>va_list</tt> and causes the
4254<tt>va_list</tt> to point to the next argument. For more information,
4255see the variable argument handling <a href="#int_varargs">Intrinsic
4256Functions</a>.</p>
4257
4258<p>It is legal for this instruction to be called in a function which does not
4259take a variable number of arguments, for example, the <tt>vfprintf</tt>
4260function.</p>
4261
4262<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
4263href="#intrinsics">intrinsic function</a> because it takes a type as an
4264argument.</p>
4265
4266<h5>Example:</h5>
4267
4268<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4269
4270</div>
4271
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4272<!-- _______________________________________________________________________ -->
4273<div class="doc_subsubsection">
4274 <a name="i_getresult">'<tt>getresult</tt>' Instruction</a>
4275</div>
4276
4277<div class="doc_text">
4278
4279<h5>Syntax:</h5>
4280<pre>
Chris Lattneree9da3f2008-03-21 17:20:51 +0000[diff] [blame]4281 &lt;resultval&gt; = getresult &lt;type&gt; &lt;retval&gt;, &lt;index&gt;
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4282</pre>
Chris Lattneree9da3f2008-03-21 17:20:51 +0000[diff] [blame]4283
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4284<h5>Overview:</h5>
4285
4286<p> The '<tt>getresult</tt>' instruction is used to extract individual values
Chris Lattneree9da3f2008-03-21 17:20:51 +0000[diff] [blame]4287from a '<tt><a href="#i_call">call</a></tt>'
4288or '<tt><a href="#i_invoke">invoke</a></tt>' instruction that returns multiple
4289results.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4290
4291<h5>Arguments:</h5>
4292
Chris Lattneree9da3f2008-03-21 17:20:51 +0000[diff] [blame]4293<p>The '<tt>getresult</tt>' instruction takes a call or invoke value as its
Chris Lattnerd8dd3522008-04-23 04:06:52 +0000[diff] [blame]4294first argument, or an undef value. The value must have <a
4295href="#t_struct">structure type</a>. The second argument is a constant
4296unsigned index value which must be in range for the number of values returned
4297by the call.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4298
4299<h5>Semantics:</h5>
4300
Chris Lattneree9da3f2008-03-21 17:20:51 +0000[diff] [blame]4301<p>The '<tt>getresult</tt>' instruction extracts the element identified by
4302'<tt>index</tt>' from the aggregate value.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4303
4304<h5>Example:</h5>
4305
4306<pre>
4307 %struct.A = type { i32, i8 }
4308
4309 %r = call %struct.A @foo()
Chris Lattneree9da3f2008-03-21 17:20:51 +0000[diff] [blame]4310 %gr = getresult %struct.A %r, 0 <i>; yields i32:%gr</i>
4311 %gr1 = getresult %struct.A %r, 1 <i>; yields i8:%gr1</i>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4312 add i32 %gr, 42
4313 add i8 %gr1, 41
4314</pre>
4315
4316</div>
4317
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4318<!-- *********************************************************************** -->
4319<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4320<!-- *********************************************************************** -->
4321
4322<div class="doc_text">
4323
4324<p>LLVM supports the notion of an "intrinsic function". These functions have
4325well known names and semantics and are required to follow certain restrictions.
4326Overall, these intrinsics represent an extension mechanism for the LLVM
4327language that does not require changing all of the transformations in LLVM when
4328adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
4329
4330<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
4331prefix is reserved in LLVM for intrinsic names; thus, function names may not
4332begin with this prefix. Intrinsic functions must always be external functions:
4333you cannot define the body of intrinsic functions. Intrinsic functions may
4334only be used in call or invoke instructions: it is illegal to take the address
4335of an intrinsic function. Additionally, because intrinsic functions are part
4336of the LLVM language, it is required if any are added that they be documented
4337here.</p>
4338
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4339<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4340a family of functions that perform the same operation but on different data
4341types. Because LLVM can represent over 8 million different integer types,
4342overloading is used commonly to allow an intrinsic function to operate on any
4343integer type. One or more of the argument types or the result type can be
4344overloaded to accept any integer type. Argument types may also be defined as
4345exactly matching a previous argument's type or the result type. This allows an
4346intrinsic function which accepts multiple arguments, but needs all of them to
4347be of the same type, to only be overloaded with respect to a single argument or
4348the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4349
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4350<p>Overloaded intrinsics will have the names of its overloaded argument types
4351encoded into its function name, each preceded by a period. Only those types
4352which are overloaded result in a name suffix. Arguments whose type is matched
4353against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4354take an integer of any width and returns an integer of exactly the same integer
4355width. This leads to a family of functions such as
4356<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4357Only one type, the return type, is overloaded, and only one type suffix is
4358required. Because the argument's type is matched against the return type, it
4359does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4360
4361<p>To learn how to add an intrinsic function, please see the
4362<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
4363</p>
4364
4365</div>
4366
4367<!-- ======================================================================= -->
4368<div class="doc_subsection">
4369 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4370</div>
4371
4372<div class="doc_text">
4373
4374<p>Variable argument support is defined in LLVM with the <a
4375 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4376intrinsic functions. These functions are related to the similarly
4377named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
4378
4379<p>All of these functions operate on arguments that use a
4380target-specific value type "<tt>va_list</tt>". The LLVM assembly
4381language reference manual does not define what this type is, so all
4382transformations should be prepared to handle these functions regardless of
4383the type used.</p>
4384
4385<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
4386instruction and the variable argument handling intrinsic functions are
4387used.</p>
4388
4389<div class="doc_code">
4390<pre>
4391define i32 @test(i32 %X, ...) {
4392 ; Initialize variable argument processing
4393 %ap = alloca i8*
4394 %ap2 = bitcast i8** %ap to i8*
4395 call void @llvm.va_start(i8* %ap2)
4396
4397 ; Read a single integer argument
4398 %tmp = va_arg i8** %ap, i32
4399
4400 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4401 %aq = alloca i8*
4402 %aq2 = bitcast i8** %aq to i8*
4403 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4404 call void @llvm.va_end(i8* %aq2)
4405
4406 ; Stop processing of arguments.
4407 call void @llvm.va_end(i8* %ap2)
4408 ret i32 %tmp
4409}
4410
4411declare void @llvm.va_start(i8*)
4412declare void @llvm.va_copy(i8*, i8*)
4413declare void @llvm.va_end(i8*)
4414</pre>
4415</div>
4416
4417</div>
4418
4419<!-- _______________________________________________________________________ -->
4420<div class="doc_subsubsection">
4421 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4422</div>
4423
4424
4425<div class="doc_text">
4426<h5>Syntax:</h5>
4427<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
4428<h5>Overview:</h5>
4429<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
4430<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4431href="#i_va_arg">va_arg</a></tt>.</p>
4432
4433<h5>Arguments:</h5>
4434
4435<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
4436
4437<h5>Semantics:</h5>
4438
4439<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
4440macro available in C. In a target-dependent way, it initializes the
4441<tt>va_list</tt> element to which the argument points, so that the next call to
4442<tt>va_arg</tt> will produce the first variable argument passed to the function.
4443Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
4444last argument of the function as the compiler can figure that out.</p>
4445
4446</div>
4447
4448<!-- _______________________________________________________________________ -->
4449<div class="doc_subsubsection">
4450 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
4451</div>
4452
4453<div class="doc_text">
4454<h5>Syntax:</h5>
4455<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
4456<h5>Overview:</h5>
4457
4458<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
4459which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
4460or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
4461
4462<h5>Arguments:</h5>
4463
4464<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
4465
4466<h5>Semantics:</h5>
4467
4468<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
4469macro available in C. In a target-dependent way, it destroys the
4470<tt>va_list</tt> element to which the argument points. Calls to <a
4471href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4472<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4473<tt>llvm.va_end</tt>.</p>
4474
4475</div>
4476
4477<!-- _______________________________________________________________________ -->
4478<div class="doc_subsubsection">
4479 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
4480</div>
4481
4482<div class="doc_text">
4483
4484<h5>Syntax:</h5>
4485
4486<pre>
4487 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
4488</pre>
4489
4490<h5>Overview:</h5>
4491
4492<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4493from the source argument list to the destination argument list.</p>
4494
4495<h5>Arguments:</h5>
4496
4497<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
4498The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
4499
4500
4501<h5>Semantics:</h5>
4502
4503<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4504macro available in C. In a target-dependent way, it copies the source
4505<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4506intrinsic is necessary because the <tt><a href="#int_va_start">
4507llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4508example, memory allocation.</p>
4509
4510</div>
4511
4512<!-- ======================================================================= -->
4513<div class="doc_subsection">
4514 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4515</div>
4516
4517<div class="doc_text">
4518
4519<p>
4520LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]4521Collection</a> (GC) requires the implementation and generation of these
4522intrinsics.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4523These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
4524stack</a>, as well as garbage collector implementations that require <a
4525href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
4526Front-ends for type-safe garbage collected languages should generate these
4527intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4528href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4529</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]4530
4531<p>The garbage collection intrinsics only operate on objects in the generic
4532 address space (address space zero).</p>
4533
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4534</div>
4535
4536<!-- _______________________________________________________________________ -->
4537<div class="doc_subsubsection">
4538 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
4539</div>
4540
4541<div class="doc_text">
4542
4543<h5>Syntax:</h5>
4544
4545<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4546 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4547</pre>
4548
4549<h5>Overview:</h5>
4550
4551<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
4552the code generator, and allows some metadata to be associated with it.</p>
4553
4554<h5>Arguments:</h5>
4555
4556<p>The first argument specifies the address of a stack object that contains the
4557root pointer. The second pointer (which must be either a constant or a global
4558value address) contains the meta-data to be associated with the root.</p>
4559
4560<h5>Semantics:</h5>
4561
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]4562<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]4563location. At compile-time, the code generator generates information to allow
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4564the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4565intrinsic may only be used in a function which <a href="#gc">specifies a GC
4566algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4567
4568</div>
4569
4570
4571<!-- _______________________________________________________________________ -->
4572<div class="doc_subsubsection">
4573 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
4574</div>
4575
4576<div class="doc_text">
4577
4578<h5>Syntax:</h5>
4579
4580<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4581 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4582</pre>
4583
4584<h5>Overview:</h5>
4585
4586<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4587locations, allowing garbage collector implementations that require read
4588barriers.</p>
4589
4590<h5>Arguments:</h5>
4591
4592<p>The second argument is the address to read from, which should be an address
4593allocated from the garbage collector. The first object is a pointer to the
4594start of the referenced object, if needed by the language runtime (otherwise
4595null).</p>
4596
4597<h5>Semantics:</h5>
4598
4599<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4600instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4601garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4602may only be used in a function which <a href="#gc">specifies a GC
4603algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4604
4605</div>
4606
4607
4608<!-- _______________________________________________________________________ -->
4609<div class="doc_subsubsection">
4610 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
4611</div>
4612
4613<div class="doc_text">
4614
4615<h5>Syntax:</h5>
4616
4617<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4618 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4619</pre>
4620
4621<h5>Overview:</h5>
4622
4623<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4624locations, allowing garbage collector implementations that require write
4625barriers (such as generational or reference counting collectors).</p>
4626
4627<h5>Arguments:</h5>
4628
4629<p>The first argument is the reference to store, the second is the start of the
4630object to store it to, and the third is the address of the field of Obj to
4631store to. If the runtime does not require a pointer to the object, Obj may be
4632null.</p>
4633
4634<h5>Semantics:</h5>
4635
4636<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4637instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4638garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4639may only be used in a function which <a href="#gc">specifies a GC
4640algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4641
4642</div>
4643
4644
4645
4646<!-- ======================================================================= -->
4647<div class="doc_subsection">
4648 <a name="int_codegen">Code Generator Intrinsics</a>
4649</div>
4650
4651<div class="doc_text">
4652<p>
4653These intrinsics are provided by LLVM to expose special features that may only
4654be implemented with code generator support.
4655</p>
4656
4657</div>
4658
4659<!-- _______________________________________________________________________ -->
4660<div class="doc_subsubsection">
4661 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
4662</div>
4663
4664<div class="doc_text">
4665
4666<h5>Syntax:</h5>
4667<pre>
4668 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
4669</pre>
4670
4671<h5>Overview:</h5>
4672
4673<p>
4674The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4675target-specific value indicating the return address of the current function
4676or one of its callers.
4677</p>
4678
4679<h5>Arguments:</h5>
4680
4681<p>
4682The argument to this intrinsic indicates which function to return the address
4683for. Zero indicates the calling function, one indicates its caller, etc. The
4684argument is <b>required</b> to be a constant integer value.
4685</p>
4686
4687<h5>Semantics:</h5>
4688
4689<p>
4690The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4691the return address of the specified call frame, or zero if it cannot be
4692identified. The value returned by this intrinsic is likely to be incorrect or 0
4693for arguments other than zero, so it should only be used for debugging purposes.
4694</p>
4695
4696<p>
4697Note that calling this intrinsic does not prevent function inlining or other
4698aggressive transformations, so the value returned may not be that of the obvious
4699source-language caller.
4700</p>
4701</div>
4702
4703
4704<!-- _______________________________________________________________________ -->
4705<div class="doc_subsubsection">
4706 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
4707</div>
4708
4709<div class="doc_text">
4710
4711<h5>Syntax:</h5>
4712<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4713 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4714</pre>
4715
4716<h5>Overview:</h5>
4717
4718<p>
4719The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4720target-specific frame pointer value for the specified stack frame.
4721</p>
4722
4723<h5>Arguments:</h5>
4724
4725<p>
4726The argument to this intrinsic indicates which function to return the frame
4727pointer for. Zero indicates the calling function, one indicates its caller,
4728etc. The argument is <b>required</b> to be a constant integer value.
4729</p>
4730
4731<h5>Semantics:</h5>
4732
4733<p>
4734The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4735the frame address of the specified call frame, or zero if it cannot be
4736identified. The value returned by this intrinsic is likely to be incorrect or 0
4737for arguments other than zero, so it should only be used for debugging purposes.
4738</p>
4739
4740<p>
4741Note that calling this intrinsic does not prevent function inlining or other
4742aggressive transformations, so the value returned may not be that of the obvious
4743source-language caller.
4744</p>
4745</div>
4746
4747<!-- _______________________________________________________________________ -->
4748<div class="doc_subsubsection">
4749 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
4750</div>
4751
4752<div class="doc_text">
4753
4754<h5>Syntax:</h5>
4755<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4756 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4757</pre>
4758
4759<h5>Overview:</h5>
4760
4761<p>
4762The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
4763the function stack, for use with <a href="#int_stackrestore">
4764<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4765features like scoped automatic variable sized arrays in C99.
4766</p>
4767
4768<h5>Semantics:</h5>
4769
4770<p>
4771This intrinsic returns a opaque pointer value that can be passed to <a
4772href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
4773<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4774<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4775state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4776practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4777that were allocated after the <tt>llvm.stacksave</tt> was executed.
4778</p>
4779
4780</div>
4781
4782<!-- _______________________________________________________________________ -->
4783<div class="doc_subsubsection">
4784 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
4785</div>
4786
4787<div class="doc_text">
4788
4789<h5>Syntax:</h5>
4790<pre>
4791 declare void @llvm.stackrestore(i8 * %ptr)
4792</pre>
4793
4794<h5>Overview:</h5>
4795
4796<p>
4797The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4798the function stack to the state it was in when the corresponding <a
4799href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
4800useful for implementing language features like scoped automatic variable sized
4801arrays in C99.
4802</p>
4803
4804<h5>Semantics:</h5>
4805
4806<p>
4807See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
4808</p>
4809
4810</div>
4811
4812
4813<!-- _______________________________________________________________________ -->
4814<div class="doc_subsubsection">
4815 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
4816</div>
4817
4818<div class="doc_text">
4819
4820<h5>Syntax:</h5>
4821<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4822 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]4823</pre>
4824
4825<h5>Overview:</h5>
4826
4827
4828<p>
4829The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
4830a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4831no
4832effect on the behavior of the program but can change its performance
4833characteristics.
4834</p>
4835
4836<h5>Arguments:</h5>
4837
4838<p>
4839<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4840determining if the fetch should be for a read (0) or write (1), and
4841<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
4842locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
4843<tt>locality</tt> arguments must be constant integers.
4844</p>
4845
4846<h5>Semantics:</h5>
4847
4848<p>
4849This intrinsic does not modify the behavior of the program. In particular,
4850prefetches cannot trap and do not produce a value. On targets that support this
4851intrinsic, the prefetch can provide hints to the processor cache for better
4852performance.
4853</p>
4854
4855</div>
4856
4857<!-- _______________________________________________________________________ -->
4858<div class="doc_subsubsection">
4859 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
4860</div>
4861
4862<div class="doc_text">
4863
4864<h5>Syntax:</h5>
4865<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4866 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4867</pre>
4868
4869<h5>Overview:</h5>
4870
4871
4872<p>
4873The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]4874(PC) in a region of
4875code to simulators and other tools. The method is target specific, but it is
4876expected that the marker will use exported symbols to transmit the PC of the
4877marker.
4878The marker makes no guarantees that it will remain with any specific instruction
4879after optimizations. It is possible that the presence of a marker will inhibit
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4880optimizations. The intended use is to be inserted after optimizations to allow
4881correlations of simulation runs.
4882</p>
4883
4884<h5>Arguments:</h5>
4885
4886<p>
4887<tt>id</tt> is a numerical id identifying the marker.
4888</p>
4889
4890<h5>Semantics:</h5>
4891
4892<p>
4893This intrinsic does not modify the behavior of the program. Backends that do not
4894support this intrinisic may ignore it.
4895</p>
4896
4897</div>
4898
4899<!-- _______________________________________________________________________ -->
4900<div class="doc_subsubsection">
4901 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
4902</div>
4903
4904<div class="doc_text">
4905
4906<h5>Syntax:</h5>
4907<pre>
4908 declare i64 @llvm.readcyclecounter( )
4909</pre>
4910
4911<h5>Overview:</h5>
4912
4913
4914<p>
4915The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4916counter register (or similar low latency, high accuracy clocks) on those targets
4917that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4918As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4919should only be used for small timings.
4920</p>
4921
4922<h5>Semantics:</h5>
4923
4924<p>
4925When directly supported, reading the cycle counter should not modify any memory.
4926Implementations are allowed to either return a application specific value or a
4927system wide value. On backends without support, this is lowered to a constant 0.
4928</p>
4929
4930</div>
4931
4932<!-- ======================================================================= -->
4933<div class="doc_subsection">
4934 <a name="int_libc">Standard C Library Intrinsics</a>
4935</div>
4936
4937<div class="doc_text">
4938<p>
4939LLVM provides intrinsics for a few important standard C library functions.
4940These intrinsics allow source-language front-ends to pass information about the
4941alignment of the pointer arguments to the code generator, providing opportunity
4942for more efficient code generation.
4943</p>
4944
4945</div>
4946
4947<!-- _______________________________________________________________________ -->
4948<div class="doc_subsubsection">
4949 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
4950</div>
4951
4952<div class="doc_text">
4953
4954<h5>Syntax:</h5>
4955<pre>
4956 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4957 i32 &lt;len&gt;, i32 &lt;align&gt;)
4958 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4959 i64 &lt;len&gt;, i32 &lt;align&gt;)
4960</pre>
4961
4962<h5>Overview:</h5>
4963
4964<p>
4965The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
4966location to the destination location.
4967</p>
4968
4969<p>
4970Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4971intrinsics do not return a value, and takes an extra alignment argument.
4972</p>
4973
4974<h5>Arguments:</h5>
4975
4976<p>
4977The first argument is a pointer to the destination, the second is a pointer to
4978the source. The third argument is an integer argument
4979specifying the number of bytes to copy, and the fourth argument is the alignment
4980of the source and destination locations.
4981</p>
4982
4983<p>
4984If the call to this intrinisic has an alignment value that is not 0 or 1, then
4985the caller guarantees that both the source and destination pointers are aligned
4986to that boundary.
4987</p>
4988
4989<h5>Semantics:</h5>
4990
4991<p>
4992The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
4993location to the destination location, which are not allowed to overlap. It
4994copies "len" bytes of memory over. If the argument is known to be aligned to
4995some boundary, this can be specified as the fourth argument, otherwise it should
4996be set to 0 or 1.
4997</p>
4998</div>
4999
5000
5001<!-- _______________________________________________________________________ -->
5002<div class="doc_subsubsection">
5003 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5004</div>
5005
5006<div class="doc_text">
5007
5008<h5>Syntax:</h5>
5009<pre>
5010 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5011 i32 &lt;len&gt;, i32 &lt;align&gt;)
5012 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5013 i64 &lt;len&gt;, i32 &lt;align&gt;)
5014</pre>
5015
5016<h5>Overview:</h5>
5017
5018<p>
5019The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5020location to the destination location. It is similar to the
Chris Lattnerdba16ea2008-01-06 19:51:52 +0000[diff] [blame]5021'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5022</p>
5023
5024<p>
5025Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5026intrinsics do not return a value, and takes an extra alignment argument.
5027</p>
5028
5029<h5>Arguments:</h5>
5030
5031<p>
5032The first argument is a pointer to the destination, the second is a pointer to
5033the source. The third argument is an integer argument
5034specifying the number of bytes to copy, and the fourth argument is the alignment
5035of the source and destination locations.
5036</p>
5037
5038<p>
5039If the call to this intrinisic has an alignment value that is not 0 or 1, then
5040the caller guarantees that the source and destination pointers are aligned to
5041that boundary.
5042</p>
5043
5044<h5>Semantics:</h5>
5045
5046<p>
5047The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
5048location to the destination location, which may overlap. It
5049copies "len" bytes of memory over. If the argument is known to be aligned to
5050some boundary, this can be specified as the fourth argument, otherwise it should
5051be set to 0 or 1.
5052</p>
5053</div>
5054
5055
5056<!-- _______________________________________________________________________ -->
5057<div class="doc_subsubsection">
5058 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5059</div>
5060
5061<div class="doc_text">
5062
5063<h5>Syntax:</h5>
5064<pre>
5065 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5066 i32 &lt;len&gt;, i32 &lt;align&gt;)
5067 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5068 i64 &lt;len&gt;, i32 &lt;align&gt;)
5069</pre>
5070
5071<h5>Overview:</h5>
5072
5073<p>
5074The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
5075byte value.
5076</p>
5077
5078<p>
5079Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5080does not return a value, and takes an extra alignment argument.
5081</p>
5082
5083<h5>Arguments:</h5>
5084
5085<p>
5086The first argument is a pointer to the destination to fill, the second is the
5087byte value to fill it with, the third argument is an integer
5088argument specifying the number of bytes to fill, and the fourth argument is the
5089known alignment of destination location.
5090</p>
5091
5092<p>
5093If the call to this intrinisic has an alignment value that is not 0 or 1, then
5094the caller guarantees that the destination pointer is aligned to that boundary.
5095</p>
5096
5097<h5>Semantics:</h5>
5098
5099<p>
5100The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5101the
5102destination location. If the argument is known to be aligned to some boundary,
5103this can be specified as the fourth argument, otherwise it should be set to 0 or
51041.
5105</p>
5106</div>
5107
5108
5109<!-- _______________________________________________________________________ -->
5110<div class="doc_subsubsection">
5111 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5112</div>
5113
5114<div class="doc_text">
5115
5116<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5117<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]5118floating point or vector of floating point type. Not all targets support all
5119types however.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5120<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5121 declare float @llvm.sqrt.f32(float %Val)
5122 declare double @llvm.sqrt.f64(double %Val)
5123 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5124 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5125 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5126</pre>
5127
5128<h5>Overview:</h5>
5129
5130<p>
5131The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5132returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5133<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattnerf914a002008-01-29 07:00:44 +0000[diff] [blame]5134negative numbers other than -0.0 (which allows for better optimization, because
5135there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5136defined to return -0.0 like IEEE sqrt.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5137</p>
5138
5139<h5>Arguments:</h5>
5140
5141<p>
5142The argument and return value are floating point numbers of the same type.
5143</p>
5144
5145<h5>Semantics:</h5>
5146
5147<p>
5148This function returns the sqrt of the specified operand if it is a nonnegative
5149floating point number.
5150</p>
5151</div>
5152
5153<!-- _______________________________________________________________________ -->
5154<div class="doc_subsubsection">
5155 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5156</div>
5157
5158<div class="doc_text">
5159
5160<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5161<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]5162floating point or vector of floating point type. Not all targets support all
5163types however.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5164<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5165 declare float @llvm.powi.f32(float %Val, i32 %power)
5166 declare double @llvm.powi.f64(double %Val, i32 %power)
5167 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5168 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5169 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5170</pre>
5171
5172<h5>Overview:</h5>
5173
5174<p>
5175The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5176specified (positive or negative) power. The order of evaluation of
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5177multiplications is not defined. When a vector of floating point type is
5178used, the second argument remains a scalar integer value.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5179</p>
5180
5181<h5>Arguments:</h5>
5182
5183<p>
5184The second argument is an integer power, and the first is a value to raise to
5185that power.
5186</p>
5187
5188<h5>Semantics:</h5>
5189
5190<p>
5191This function returns the first value raised to the second power with an
5192unspecified sequence of rounding operations.</p>
5193</div>
5194
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5195<!-- _______________________________________________________________________ -->
5196<div class="doc_subsubsection">
5197 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5198</div>
5199
5200<div class="doc_text">
5201
5202<h5>Syntax:</h5>
5203<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5204floating point or vector of floating point type. Not all targets support all
5205types however.
5206<pre>
5207 declare float @llvm.sin.f32(float %Val)
5208 declare double @llvm.sin.f64(double %Val)
5209 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5210 declare fp128 @llvm.sin.f128(fp128 %Val)
5211 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5212</pre>
5213
5214<h5>Overview:</h5>
5215
5216<p>
5217The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5218</p>
5219
5220<h5>Arguments:</h5>
5221
5222<p>
5223The argument and return value are floating point numbers of the same type.
5224</p>
5225
5226<h5>Semantics:</h5>
5227
5228<p>
5229This function returns the sine of the specified operand, returning the
5230same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5231conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5232</div>
5233
5234<!-- _______________________________________________________________________ -->
5235<div class="doc_subsubsection">
5236 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5237</div>
5238
5239<div class="doc_text">
5240
5241<h5>Syntax:</h5>
5242<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5243floating point or vector of floating point type. Not all targets support all
5244types however.
5245<pre>
5246 declare float @llvm.cos.f32(float %Val)
5247 declare double @llvm.cos.f64(double %Val)
5248 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5249 declare fp128 @llvm.cos.f128(fp128 %Val)
5250 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5251</pre>
5252
5253<h5>Overview:</h5>
5254
5255<p>
5256The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5257</p>
5258
5259<h5>Arguments:</h5>
5260
5261<p>
5262The argument and return value are floating point numbers of the same type.
5263</p>
5264
5265<h5>Semantics:</h5>
5266
5267<p>
5268This function returns the cosine of the specified operand, returning the
5269same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5270conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5271</div>
5272
5273<!-- _______________________________________________________________________ -->
5274<div class="doc_subsubsection">
5275 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5276</div>
5277
5278<div class="doc_text">
5279
5280<h5>Syntax:</h5>
5281<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5282floating point or vector of floating point type. Not all targets support all
5283types however.
5284<pre>
5285 declare float @llvm.pow.f32(float %Val, float %Power)
5286 declare double @llvm.pow.f64(double %Val, double %Power)
5287 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5288 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5289 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5290</pre>
5291
5292<h5>Overview:</h5>
5293
5294<p>
5295The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5296specified (positive or negative) power.
5297</p>
5298
5299<h5>Arguments:</h5>
5300
5301<p>
5302The second argument is a floating point power, and the first is a value to
5303raise to that power.
5304</p>
5305
5306<h5>Semantics:</h5>
5307
5308<p>
5309This function returns the first value raised to the second power,
5310returning the
5311same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5312conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5313</div>
5314
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5315
5316<!-- ======================================================================= -->
5317<div class="doc_subsection">
5318 <a name="int_manip">Bit Manipulation Intrinsics</a>
5319</div>
5320
5321<div class="doc_text">
5322<p>
5323LLVM provides intrinsics for a few important bit manipulation operations.
5324These allow efficient code generation for some algorithms.
5325</p>
5326
5327</div>
5328
5329<!-- _______________________________________________________________________ -->
5330<div class="doc_subsubsection">
5331 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5332</div>
5333
5334<div class="doc_text">
5335
5336<h5>Syntax:</h5>
5337<p>This is an overloaded intrinsic function. You can use bswap on any integer
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5338type that is an even number of bytes (i.e. BitWidth % 16 == 0).
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5339<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5340 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5341 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5342 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5343</pre>
5344
5345<h5>Overview:</h5>
5346
5347<p>
5348The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5349values with an even number of bytes (positive multiple of 16 bits). These are
5350useful for performing operations on data that is not in the target's native
5351byte order.
5352</p>
5353
5354<h5>Semantics:</h5>
5355
5356<p>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5357The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5358and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5359intrinsic returns an i32 value that has the four bytes of the input i32
5360swapped, 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]5361i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5362<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5363additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
5364</p>
5365
5366</div>
5367
5368<!-- _______________________________________________________________________ -->
5369<div class="doc_subsubsection">
5370 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5371</div>
5372
5373<div class="doc_text">
5374
5375<h5>Syntax:</h5>
5376<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
5377width. Not all targets support all bit widths however.
5378<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5379 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
5380 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5381 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5382 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5383 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5384</pre>
5385
5386<h5>Overview:</h5>
5387
5388<p>
5389The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5390value.
5391</p>
5392
5393<h5>Arguments:</h5>
5394
5395<p>
5396The only argument is the value to be counted. The argument may be of any
5397integer type. The return type must match the argument type.
5398</p>
5399
5400<h5>Semantics:</h5>
5401
5402<p>
5403The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5404</p>
5405</div>
5406
5407<!-- _______________________________________________________________________ -->
5408<div class="doc_subsubsection">
5409 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5410</div>
5411
5412<div class="doc_text">
5413
5414<h5>Syntax:</h5>
5415<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
5416integer bit width. Not all targets support all bit widths however.
5417<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5418 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5419 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5420 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5421 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5422 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5423</pre>
5424
5425<h5>Overview:</h5>
5426
5427<p>
5428The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5429leading zeros in a variable.
5430</p>
5431
5432<h5>Arguments:</h5>
5433
5434<p>
5435The only argument is the value to be counted. The argument may be of any
5436integer type. The return type must match the argument type.
5437</p>
5438
5439<h5>Semantics:</h5>
5440
5441<p>
5442The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5443in a variable. If the src == 0 then the result is the size in bits of the type
5444of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
5445</p>
5446</div>
5447
5448
5449
5450<!-- _______________________________________________________________________ -->
5451<div class="doc_subsubsection">
5452 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5453</div>
5454
5455<div class="doc_text">
5456
5457<h5>Syntax:</h5>
5458<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
5459integer bit width. Not all targets support all bit widths however.
5460<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5461 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5462 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5463 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5464 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5465 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5466</pre>
5467
5468<h5>Overview:</h5>
5469
5470<p>
5471The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5472trailing zeros.
5473</p>
5474
5475<h5>Arguments:</h5>
5476
5477<p>
5478The only argument is the value to be counted. The argument may be of any
5479integer type. The return type must match the argument type.
5480</p>
5481
5482<h5>Semantics:</h5>
5483
5484<p>
5485The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5486in a variable. If the src == 0 then the result is the size in bits of the type
5487of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5488</p>
5489</div>
5490
5491<!-- _______________________________________________________________________ -->
5492<div class="doc_subsubsection">
5493 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
5494</div>
5495
5496<div class="doc_text">
5497
5498<h5>Syntax:</h5>
5499<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
5500on any integer bit width.
5501<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5502 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5503 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5504</pre>
5505
5506<h5>Overview:</h5>
5507<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
5508range of bits from an integer value and returns them in the same bit width as
5509the original value.</p>
5510
5511<h5>Arguments:</h5>
5512<p>The first argument, <tt>%val</tt> and the result may be integer types of
5513any bit width but they must have the same bit width. The second and third
5514arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
5515
5516<h5>Semantics:</h5>
5517<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
5518of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5519<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5520operates in forward mode.</p>
5521<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5522right by <tt>%loBit</tt> bits and then ANDing it with a mask with
5523only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5524<ol>
5525 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5526 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5527 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5528 to determine the number of bits to retain.</li>
5529 <li>A mask of the retained bits is created by shifting a -1 value.</li>
5530 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
5531</ol>
5532<p>In reverse mode, a similar computation is made except that the bits are
5533returned in the reverse order. So, for example, if <tt>X</tt> has the value
5534<tt>i16 0x0ACF (101011001111)</tt> and we apply
5535<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5536<tt>i16 0x0026 (000000100110)</tt>.</p>
5537</div>
5538
5539<div class="doc_subsubsection">
5540 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5541</div>
5542
5543<div class="doc_text">
5544
5545<h5>Syntax:</h5>
5546<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
5547on any integer bit width.
5548<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5549 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5550 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]5551</pre>
5552
5553<h5>Overview:</h5>
5554<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5555of bits in an integer value with another integer value. It returns the integer
5556with the replaced bits.</p>
5557
5558<h5>Arguments:</h5>
5559<p>The first argument, <tt>%val</tt> and the result may be integer types of
5560any bit width but they must have the same bit width. <tt>%val</tt> is the value
5561whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5562integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5563type since they specify only a bit index.</p>
5564
5565<h5>Semantics:</h5>
5566<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5567of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5568<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5569operates in forward mode.</p>
5570<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5571truncating it down to the size of the replacement area or zero extending it
5572up to that size.</p>
5573<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5574are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5575in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
5576to the <tt>%hi</tt>th bit.
5577<p>In reverse mode, a similar computation is made except that the bits are
5578reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
5579<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.
5580<h5>Examples:</h5>
5581<pre>
5582 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
5583 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5584 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5585 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
5586 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
5587</pre>
5588</div>
5589
5590<!-- ======================================================================= -->
5591<div class="doc_subsection">
5592 <a name="int_debugger">Debugger Intrinsics</a>
5593</div>
5594
5595<div class="doc_text">
5596<p>
5597The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5598are described in the <a
5599href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5600Debugging</a> document.
5601</p>
5602</div>
5603
5604
5605<!-- ======================================================================= -->
5606<div class="doc_subsection">
5607 <a name="int_eh">Exception Handling Intrinsics</a>
5608</div>
5609
5610<div class="doc_text">
5611<p> The LLVM exception handling intrinsics (which all start with
5612<tt>llvm.eh.</tt> prefix), are described in the <a
5613href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5614Handling</a> document. </p>
5615</div>
5616
5617<!-- ======================================================================= -->
5618<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5619 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5620</div>
5621
5622<div class="doc_text">
5623<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5624 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5625 the <tt>nest</tt> attribute, from a function. The result is a callable
5626 function pointer lacking the nest parameter - the caller does not need
5627 to provide a value for it. Instead, the value to use is stored in
5628 advance in a "trampoline", a block of memory usually allocated
5629 on the stack, which also contains code to splice the nest value into the
5630 argument list. This is used to implement the GCC nested function address
5631 extension.
5632</p>
5633<p>
5634 For example, if the function is
5635 <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]5636 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]5637<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5638 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5639 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5640 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5641 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5642</pre>
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]5643 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5644 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5645</div>
5646
5647<!-- _______________________________________________________________________ -->
5648<div class="doc_subsubsection">
5649 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5650</div>
5651<div class="doc_text">
5652<h5>Syntax:</h5>
5653<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5654declare 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]5655</pre>
5656<h5>Overview:</h5>
5657<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5658 This fills the memory pointed to by <tt>tramp</tt> with code
5659 and returns a function pointer suitable for executing it.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5660</p>
5661<h5>Arguments:</h5>
5662<p>
5663 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5664 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5665 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sands35012212007-08-22 23:39:54 +0000[diff] [blame]5666 intrinsic. Note that the size and the alignment are target-specific - LLVM
5667 currently provides no portable way of determining them, so a front-end that
5668 generates this intrinsic needs to have some target-specific knowledge.
5669 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]5670</p>
5671<h5>Semantics:</h5>
5672<p>
5673 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5674 dependent code, turning it into a function. A pointer to this function is
5675 returned, but needs to be bitcast to an
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5676 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5677 before being called. The new function's signature is the same as that of
5678 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5679 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5680 of pointer type. Calling the new function is equivalent to calling
5681 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5682 missing <tt>nest</tt> argument. If, after calling
5683 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5684 modified, then the effect of any later call to the returned function pointer is
5685 undefined.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5686</p>
5687</div>
5688
5689<!-- ======================================================================= -->
5690<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5691 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
5692</div>
5693
5694<div class="doc_text">
5695<p>
5696 These intrinsic functions expand the "universal IR" of LLVM to represent
5697 hardware constructs for atomic operations and memory synchronization. This
5698 provides an interface to the hardware, not an interface to the programmer. It
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5699 is aimed at a low enough level to allow any programming models or APIs
5700 (Application Programming Interfaces) which
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5701 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
5702 hardware behavior. Just as hardware provides a "universal IR" for source
5703 languages, it also provides a starting point for developing a "universal"
5704 atomic operation and synchronization IR.
5705</p>
5706<p>
5707 These do <em>not</em> form an API such as high-level threading libraries,
5708 software transaction memory systems, atomic primitives, and intrinsic
5709 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
5710 application libraries. The hardware interface provided by LLVM should allow
5711 a clean implementation of all of these APIs and parallel programming models.
5712 No one model or paradigm should be selected above others unless the hardware
5713 itself ubiquitously does so.
5714
5715</p>
5716</div>
5717
5718<!-- _______________________________________________________________________ -->
5719<div class="doc_subsubsection">
5720 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5721</div>
5722<div class="doc_text">
5723<h5>Syntax:</h5>
5724<pre>
5725declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
5726i1 &lt;device&gt; )
5727
5728</pre>
5729<h5>Overview:</h5>
5730<p>
5731 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5732 specific pairs of memory access types.
5733</p>
5734<h5>Arguments:</h5>
5735<p>
5736 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
5737 The first four arguments enables a specific barrier as listed below. The fith
5738 argument specifies that the barrier applies to io or device or uncached memory.
5739
5740</p>
5741 <ul>
5742 <li><tt>ll</tt>: load-load barrier</li>
5743 <li><tt>ls</tt>: load-store barrier</li>
5744 <li><tt>sl</tt>: store-load barrier</li>
5745 <li><tt>ss</tt>: store-store barrier</li>
5746 <li><tt>device</tt>: barrier applies to device and uncached memory also.
5747 </ul>
5748<h5>Semantics:</h5>
5749<p>
5750 This intrinsic causes the system to enforce some ordering constraints upon
5751 the loads and stores of the program. This barrier does not indicate
5752 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5753 which they occur. For any of the specified pairs of load and store operations
5754 (f.ex. load-load, or store-load), all of the first operations preceding the
5755 barrier will complete before any of the second operations succeeding the
5756 barrier begin. Specifically the semantics for each pairing is as follows:
5757</p>
5758 <ul>
5759 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5760 after the barrier begins.</li>
5761
5762 <li><tt>ls</tt>: All loads before the barrier must complete before any
5763 store after the barrier begins.</li>
5764 <li><tt>ss</tt>: All stores before the barrier must complete before any
5765 store after the barrier begins.</li>
5766 <li><tt>sl</tt>: All stores before the barrier must complete before any
5767 load after the barrier begins.</li>
5768 </ul>
5769<p>
5770 These semantics are applied with a logical "and" behavior when more than one
5771 is enabled in a single memory barrier intrinsic.
5772</p>
5773<p>
5774 Backends may implement stronger barriers than those requested when they do not
5775 support as fine grained a barrier as requested. Some architectures do not
5776 need all types of barriers and on such architectures, these become noops.
5777</p>
5778<h5>Example:</h5>
5779<pre>
5780%ptr = malloc i32
5781 store i32 4, %ptr
5782
5783%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
5784 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
5785 <i>; guarantee the above finishes</i>
5786 store i32 8, %ptr <i>; before this begins</i>
5787</pre>
5788</div>
5789
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5790<!-- _______________________________________________________________________ -->
5791<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5792 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5793</div>
5794<div class="doc_text">
5795<h5>Syntax:</h5>
5796<p>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5797 This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
5798 any integer bit width and for different address spaces. Not all targets
5799 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5800
5801<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5802declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
5803declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
5804declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
5805declare i64 @llvm.atomic.cmp.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5806
5807</pre>
5808<h5>Overview:</h5>
5809<p>
5810 This loads a value in memory and compares it to a given value. If they are
5811 equal, it stores a new value into the memory.
5812</p>
5813<h5>Arguments:</h5>
5814<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5815 The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5816 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
5817 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
5818 this integer type. While any bit width integer may be used, targets may only
5819 lower representations they support in hardware.
5820
5821</p>
5822<h5>Semantics:</h5>
5823<p>
5824 This entire intrinsic must be executed atomically. It first loads the value
5825 in memory pointed to by <tt>ptr</tt> and compares it with the value
5826 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
5827 loaded value is yielded in all cases. This provides the equivalent of an
5828 atomic compare-and-swap operation within the SSA framework.
5829</p>
5830<h5>Examples:</h5>
5831
5832<pre>
5833%ptr = malloc i32
5834 store i32 4, %ptr
5835
5836%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5837%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5838 <i>; yields {i32}:result1 = 4</i>
5839%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5840%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5841
5842%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5843%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5844 <i>; yields {i32}:result2 = 8</i>
5845%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
5846
5847%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
5848</pre>
5849</div>
5850
5851<!-- _______________________________________________________________________ -->
5852<div class="doc_subsubsection">
5853 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
5854</div>
5855<div class="doc_text">
5856<h5>Syntax:</h5>
5857
5858<p>
5859 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
5860 integer bit width. Not all targets support all bit widths however.</p>
5861<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5862declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
5863declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
5864declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
5865declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5866
5867</pre>
5868<h5>Overview:</h5>
5869<p>
5870 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
5871 the value from memory. It then stores the value in <tt>val</tt> in the memory
5872 at <tt>ptr</tt>.
5873</p>
5874<h5>Arguments:</h5>
5875
5876<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5877 The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5878 <tt>val</tt> argument and the result must be integers of the same bit width.
5879 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
5880 integer type. The targets may only lower integer representations they
5881 support.
5882</p>
5883<h5>Semantics:</h5>
5884<p>
5885 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
5886 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
5887 equivalent of an atomic swap operation within the SSA framework.
5888
5889</p>
5890<h5>Examples:</h5>
5891<pre>
5892%ptr = malloc i32
5893 store i32 4, %ptr
5894
5895%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5896%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5897 <i>; yields {i32}:result1 = 4</i>
5898%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5899%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5900
5901%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5902%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5903 <i>; yields {i32}:result2 = 8</i>
5904
5905%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
5906%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
5907</pre>
5908</div>
5909
5910<!-- _______________________________________________________________________ -->
5911<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5912 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5913
5914</div>
5915<div class="doc_text">
5916<h5>Syntax:</h5>
5917<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5918 This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on any
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5919 integer bit width. Not all targets support all bit widths however.</p>
5920<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5921declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
5922declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
5923declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
5924declare i64 @llvm.atomic.load.add.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5925
5926</pre>
5927<h5>Overview:</h5>
5928<p>
5929 This intrinsic adds <tt>delta</tt> to the value stored in memory at
5930 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
5931</p>
5932<h5>Arguments:</h5>
5933<p>
5934
5935 The intrinsic takes two arguments, the first a pointer to an integer value
5936 and the second an integer value. The result is also an integer value. These
5937 integer types can have any bit width, but they must all have the same bit
5938 width. The targets may only lower integer representations they support.
5939</p>
5940<h5>Semantics:</h5>
5941<p>
5942 This intrinsic does a series of operations atomically. It first loads the
5943 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
5944 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
5945</p>
5946
5947<h5>Examples:</h5>
5948<pre>
5949%ptr = malloc i32
5950 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5951%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5952 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5953%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5954 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5955%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5956 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5957%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5958</pre>
5959</div>
5960
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5961<!-- _______________________________________________________________________ -->
5962<div class="doc_subsubsection">
5963 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
5964
5965</div>
5966<div class="doc_text">
5967<h5>Syntax:</h5>
5968<p>
5969 This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5970 any integer bit width and for different address spaces. Not all targets
5971 support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5972<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5973declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
5974declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
5975declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
5976declare i64 @llvm.atomic.load.sub.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5977
5978</pre>
5979<h5>Overview:</h5>
5980<p>
5981 This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
5982 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
5983</p>
5984<h5>Arguments:</h5>
5985<p>
5986
5987 The intrinsic takes two arguments, the first a pointer to an integer value
5988 and the second an integer value. The result is also an integer value. These
5989 integer types can have any bit width, but they must all have the same bit
5990 width. The targets may only lower integer representations they support.
5991</p>
5992<h5>Semantics:</h5>
5993<p>
5994 This intrinsic does a series of operations atomically. It first loads the
5995 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
5996 result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
5997</p>
5998
5999<h5>Examples:</h5>
6000<pre>
6001%ptr = malloc i32
6002 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6003%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6004 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6005%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6006 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6007%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6008 <i>; yields {i32}:result3 = 2</i>
6009%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6010</pre>
6011</div>
6012
6013<!-- _______________________________________________________________________ -->
6014<div class="doc_subsubsection">
6015 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6016 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6017 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6018 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
6019
6020</div>
6021<div class="doc_text">
6022<h5>Syntax:</h5>
6023<p>
6024 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
6025 <tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6026 <tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
6027 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6028<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6029declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6030declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6031declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6032declare i64 @llvm.atomic.load.and.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6033
6034</pre>
6035
6036<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6037declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6038declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6039declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6040declare i64 @llvm.atomic.load.or.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6041
6042</pre>
6043
6044<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6045declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6046declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6047declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6048declare i64 @llvm.atomic.load.nand.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6049
6050</pre>
6051
6052<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6053declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6054declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6055declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6056declare i64 @llvm.atomic.load.xor.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6057
6058</pre>
6059<h5>Overview:</h5>
6060<p>
6061 These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6062 the value stored in memory at <tt>ptr</tt>. It yields the original value
6063 at <tt>ptr</tt>.
6064</p>
6065<h5>Arguments:</h5>
6066<p>
6067
6068 These intrinsics take two arguments, the first a pointer to an integer value
6069 and the second an integer value. The result is also an integer value. These
6070 integer types can have any bit width, but they must all have the same bit
6071 width. The targets may only lower integer representations they support.
6072</p>
6073<h5>Semantics:</h5>
6074<p>
6075 These intrinsics does a series of operations atomically. They first load the
6076 value stored at <tt>ptr</tt>. They then do the bitwise operation
6077 <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
6078 value stored at <tt>ptr</tt>.
6079</p>
6080
6081<h5>Examples:</h5>
6082<pre>
6083%ptr = malloc i32
6084 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6085%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6086 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6087%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6088 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6089%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6090 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6091%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6092 <i>; yields {i32}:result3 = FF</i>
6093%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6094</pre>
6095</div>
6096
6097
6098<!-- _______________________________________________________________________ -->
6099<div class="doc_subsubsection">
6100 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6101 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6102 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6103 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
6104
6105</div>
6106<div class="doc_text">
6107<h5>Syntax:</h5>
6108<p>
6109 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6110 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6111 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6112 address spaces. Not all targets
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6113 support all bit widths however.</p>
6114<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6115declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6116declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6117declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6118declare i64 @llvm.atomic.load.max.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6119
6120</pre>
6121
6122<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6123declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6124declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6125declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6126declare i64 @llvm.atomic.load.min.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6127
6128</pre>
6129
6130<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6131declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6132declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6133declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6134declare i64 @llvm.atomic.load.umax.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6135
6136</pre>
6137
6138<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6139declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6140declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6141declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6142declare i64 @llvm.atomic.load.umin.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6143
6144</pre>
6145<h5>Overview:</h5>
6146<p>
6147 These intrinsics takes the signed or unsigned minimum or maximum of
6148 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6149 original value at <tt>ptr</tt>.
6150</p>
6151<h5>Arguments:</h5>
6152<p>
6153
6154 These intrinsics take two arguments, the first a pointer to an integer value
6155 and the second an integer value. The result is also an integer value. These
6156 integer types can have any bit width, but they must all have the same bit
6157 width. The targets may only lower integer representations they support.
6158</p>
6159<h5>Semantics:</h5>
6160<p>
6161 These intrinsics does a series of operations atomically. They first load the
6162 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
6163 <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
6164 the original value stored at <tt>ptr</tt>.
6165</p>
6166
6167<h5>Examples:</h5>
6168<pre>
6169%ptr = malloc i32
6170 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6171%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6172 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6173%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6174 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6175%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6176 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6177%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6178 <i>; yields {i32}:result3 = 8</i>
6179%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6180</pre>
6181</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6182
6183<!-- ======================================================================= -->
6184<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6185 <a name="int_general">General Intrinsics</a>
6186</div>
6187
6188<div class="doc_text">
6189<p> This class of intrinsics is designed to be generic and has
6190no specific purpose. </p>
6191</div>
6192
6193<!-- _______________________________________________________________________ -->
6194<div class="doc_subsubsection">
6195 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6196</div>
6197
6198<div class="doc_text">
6199
6200<h5>Syntax:</h5>
6201<pre>
6202 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6203</pre>
6204
6205<h5>Overview:</h5>
6206
6207<p>
6208The '<tt>llvm.var.annotation</tt>' intrinsic
6209</p>
6210
6211<h5>Arguments:</h5>
6212
6213<p>
6214The first argument is a pointer to a value, the second is a pointer to a
6215global string, the third is a pointer to a global string which is the source
6216file name, and the last argument is the line number.
6217</p>
6218
6219<h5>Semantics:</h5>
6220
6221<p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6222This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6223This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6224annotations. These have no other defined use, they are ignored by code
6225generation and optimization.
6226</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6227</div>
6228
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6229<!-- _______________________________________________________________________ -->
6230<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]6231 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6232</div>
6233
6234<div class="doc_text">
6235
6236<h5>Syntax:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6237<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6238any integer bit width.
6239</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6240<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]6241 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6242 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6243 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6244 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6245 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]6246</pre>
6247
6248<h5>Overview:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6249
6250<p>
6251The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6252</p>
6253
6254<h5>Arguments:</h5>
6255
6256<p>
6257The first argument is an integer value (result of some expression),
6258the second is a pointer to a global string, the third is a pointer to a global
6259string which is the source file name, and the last argument is the line number.
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6260It returns the value of the first argument.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6261</p>
6262
6263<h5>Semantics:</h5>
6264
6265<p>
6266This intrinsic allows annotations to be put on arbitrary expressions
6267with arbitrary strings. This can be useful for special purpose optimizations
6268that want to look for these annotations. These have no other defined use, they
6269are ignored by code generation and optimization.
6270</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6271
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6272<!-- _______________________________________________________________________ -->
6273<div class="doc_subsubsection">
6274 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6275</div>
6276
6277<div class="doc_text">
6278
6279<h5>Syntax:</h5>
6280<pre>
6281 declare void @llvm.trap()
6282</pre>
6283
6284<h5>Overview:</h5>
6285
6286<p>
6287The '<tt>llvm.trap</tt>' intrinsic
6288</p>
6289
6290<h5>Arguments:</h5>
6291
6292<p>
6293None
6294</p>
6295
6296<h5>Semantics:</h5>
6297
6298<p>
6299This intrinsics is lowered to the target dependent trap instruction. If the
6300target does not have a trap instruction, this intrinsic will be lowered to the
6301call of the abort() function.
6302</p>
6303</div>
6304
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6305<!-- *********************************************************************** -->
6306<hr>
6307<address>
6308 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
6309 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
6310 <a href="http://validator.w3.org/check/referer"><img
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]6311 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6312
6313 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
6314 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
6315 Last modified: $Date$
6316</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]6317
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6318</body>
6319</html>