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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>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]25 <li><a href="#namedtypes">Named Types</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]26 <li><a href="#globalvars">Global Variables</a></li>
27 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]28 <li><a href="#aliasstructure">Aliases</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]29 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]30 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]31 <li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]32 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
33 <li><a href="#datalayout">Data Layout</a></li>
34 </ol>
35 </li>
36 <li><a href="#typesystem">Type System</a>
37 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]38 <li><a href="#t_classifications">Type Classifications</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]39 <li><a href="#t_primitive">Primitive Types</a>
40 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]41 <li><a href="#t_floating">Floating Point Types</a></li>
42 <li><a href="#t_void">Void Type</a></li>
43 <li><a href="#t_label">Label Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]44 </ol>
45 </li>
46 <li><a href="#t_derived">Derived Types</a>
47 <ol>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]48 <li><a href="#t_integer">Integer Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]49 <li><a href="#t_array">Array Type</a></li>
50 <li><a href="#t_function">Function Type</a></li>
51 <li><a href="#t_pointer">Pointer Type</a></li>
52 <li><a href="#t_struct">Structure Type</a></li>
53 <li><a href="#t_pstruct">Packed Structure Type</a></li>
54 <li><a href="#t_vector">Vector Type</a></li>
55 <li><a href="#t_opaque">Opaque Type</a></li>
56 </ol>
57 </li>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]58 <li><a href="#t_uprefs">Type Up-references</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]59 </ol>
60 </li>
61 <li><a href="#constants">Constants</a>
62 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]63 <li><a href="#simpleconstants">Simple Constants</a></li>
64 <li><a href="#aggregateconstants">Aggregate Constants</a></li>
65 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
66 <li><a href="#undefvalues">Undefined Values</a></li>
67 <li><a href="#constantexprs">Constant Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]68 </ol>
69 </li>
70 <li><a href="#othervalues">Other Values</a>
71 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]72 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]73 </ol>
74 </li>
75 <li><a href="#instref">Instruction Reference</a>
76 <ol>
77 <li><a href="#terminators">Terminator Instructions</a>
78 <ol>
79 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
80 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
81 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
82 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
83 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
84 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
85 </ol>
86 </li>
87 <li><a href="#binaryops">Binary Operations</a>
88 <ol>
89 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
90 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
91 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
92 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
93 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
94 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
95 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
96 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
97 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
98 </ol>
99 </li>
100 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
101 <ol>
102 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
103 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
104 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
105 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
106 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
107 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
108 </ol>
109 </li>
110 <li><a href="#vectorops">Vector Operations</a>
111 <ol>
112 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
113 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
114 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
115 </ol>
116 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]117 <li><a href="#aggregateops">Aggregate Operations</a>
118 <ol>
119 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
120 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
121 </ol>
122 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]123 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
124 <ol>
125 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
126 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
127 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
128 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
129 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
130 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
131 </ol>
132 </li>
133 <li><a href="#convertops">Conversion Operations</a>
134 <ol>
135 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
136 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
137 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
138 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
139 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
140 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
141 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
142 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
143 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
144 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
145 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
146 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
147 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]148 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]149 <li><a href="#otherops">Other Operations</a>
150 <ol>
151 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
152 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]153 <li><a href="#i_vicmp">'<tt>vicmp</tt>' Instruction</a></li>
154 <li><a href="#i_vfcmp">'<tt>vfcmp</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]155 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
156 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
157 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
158 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
159 </ol>
160 </li>
161 </ol>
162 </li>
163 <li><a href="#intrinsics">Intrinsic Functions</a>
164 <ol>
165 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
166 <ol>
167 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
168 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
169 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
170 </ol>
171 </li>
172 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
173 <ol>
174 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
175 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
176 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
177 </ol>
178 </li>
179 <li><a href="#int_codegen">Code Generator Intrinsics</a>
180 <ol>
181 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
182 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
183 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
184 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
185 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
186 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
187 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
188 </ol>
189 </li>
190 <li><a href="#int_libc">Standard C Library Intrinsics</a>
191 <ol>
192 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
193 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
194 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
195 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
196 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]197 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
198 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
199 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]200 </ol>
201 </li>
202 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
203 <ol>
204 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
205 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
206 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
207 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
208 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
209 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
210 </ol>
211 </li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame^]212 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
213 <ol>
214 <li><a href="#int_sadd_ovf">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
215 <li><a href="#int_uadd_ovf">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
216 <li><a href="#int_ssub_ovf">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
217 <li><a href="#int_usub_ovf">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
218 <li><a href="#int_smul_ovf">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
219 </ol>
220 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]221 <li><a href="#int_debugger">Debugger intrinsics</a></li>
222 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]223 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]224 <ol>
225 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]226 </ol>
227 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]228 <li><a href="#int_atomics">Atomic intrinsics</a>
229 <ol>
230 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
231 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
232 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
233 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
234 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
235 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
236 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
237 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
238 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
239 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
240 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
241 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
242 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
243 </ol>
244 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]245 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]246 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]247 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]248 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]249 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]250 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]251 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]252 '<tt>llvm.trap</tt>' Intrinsic</a></li>
253 <li><a href="#int_stackprotector">
254 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]255 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]256 </li>
257 </ol>
258 </li>
259</ol>
260
261<div class="doc_author">
262 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
263 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
264</div>
265
266<!-- *********************************************************************** -->
267<div class="doc_section"> <a name="abstract">Abstract </a></div>
268<!-- *********************************************************************** -->
269
270<div class="doc_text">
271<p>This document is a reference manual for the LLVM assembly language.
Bill Wendlinge7846a52008-08-05 22:29:16 +0000[diff] [blame]272LLVM is a Static Single Assignment (SSA) based representation that provides
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]273type safety, low-level operations, flexibility, and the capability of
274representing 'all' high-level languages cleanly. It is the common code
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]275representation used throughout all phases of the LLVM compilation
276strategy.</p>
277</div>
278
279<!-- *********************************************************************** -->
280<div class="doc_section"> <a name="introduction">Introduction</a> </div>
281<!-- *********************************************************************** -->
282
283<div class="doc_text">
284
285<p>The LLVM code representation is designed to be used in three
286different forms: as an in-memory compiler IR, as an on-disk bitcode
287representation (suitable for fast loading by a Just-In-Time compiler),
288and as a human readable assembly language representation. This allows
289LLVM to provide a powerful intermediate representation for efficient
290compiler transformations and analysis, while providing a natural means
291to debug and visualize the transformations. The three different forms
292of LLVM are all equivalent. This document describes the human readable
293representation and notation.</p>
294
295<p>The LLVM representation aims to be light-weight and low-level
296while being expressive, typed, and extensible at the same time. It
297aims to be a "universal IR" of sorts, by being at a low enough level
298that high-level ideas may be cleanly mapped to it (similar to how
299microprocessors are "universal IR's", allowing many source languages to
300be mapped to them). By providing type information, LLVM can be used as
301the target of optimizations: for example, through pointer analysis, it
302can be proven that a C automatic variable is never accessed outside of
303the current function... allowing it to be promoted to a simple SSA
304value instead of a memory location.</p>
305
306</div>
307
308<!-- _______________________________________________________________________ -->
309<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
310
311<div class="doc_text">
312
313<p>It is important to note that this document describes 'well formed'
314LLVM assembly language. There is a difference between what the parser
315accepts and what is considered 'well formed'. For example, the
316following instruction is syntactically okay, but not well formed:</p>
317
318<div class="doc_code">
319<pre>
320%x = <a href="#i_add">add</a> i32 1, %x
321</pre>
322</div>
323
324<p>...because the definition of <tt>%x</tt> does not dominate all of
325its uses. The LLVM infrastructure provides a verification pass that may
326be used to verify that an LLVM module is well formed. This pass is
327automatically run by the parser after parsing input assembly and by
328the optimizer before it outputs bitcode. The violations pointed out
329by the verifier pass indicate bugs in transformation passes or input to
330the parser.</p>
331</div>
332
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]333<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]334
335<!-- *********************************************************************** -->
336<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
337<!-- *********************************************************************** -->
338
339<div class="doc_text">
340
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]341 <p>LLVM identifiers come in two basic types: global and local. Global
342 identifiers (functions, global variables) begin with the @ character. Local
343 identifiers (register names, types) begin with the % character. Additionally,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]344 there are three different formats for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]345
346<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]347 <li>Named values are represented as a string of characters with their prefix.
348 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
349 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]350 Identifiers which require other characters in their names can be surrounded
Daniel Dunbar73f9a772008-10-14 23:51:43 +0000[diff] [blame]351 with quotes. Special characters may be escaped using "\xx" where xx is the
352 ASCII code for the character in hexadecimal. In this way, any character can
353 be used in a name value, even quotes themselves.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]354
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]355 <li>Unnamed values are represented as an unsigned numeric value with their
356 prefix. For example, %12, @2, %44.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]357
358 <li>Constants, which are described in a <a href="#constants">section about
359 constants</a>, below.</li>
360</ol>
361
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]362<p>LLVM requires that values start with a prefix for two reasons: Compilers
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]363don't need to worry about name clashes with reserved words, and the set of
364reserved words may be expanded in the future without penalty. Additionally,
365unnamed identifiers allow a compiler to quickly come up with a temporary
366variable without having to avoid symbol table conflicts.</p>
367
368<p>Reserved words in LLVM are very similar to reserved words in other
369languages. There are keywords for different opcodes
370('<tt><a href="#i_add">add</a></tt>',
371 '<tt><a href="#i_bitcast">bitcast</a></tt>',
372 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
373href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
374and others. These reserved words cannot conflict with variable names, because
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]375none of them start with a prefix character ('%' or '@').</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]376
377<p>Here is an example of LLVM code to multiply the integer variable
378'<tt>%X</tt>' by 8:</p>
379
380<p>The easy way:</p>
381
382<div class="doc_code">
383<pre>
384%result = <a href="#i_mul">mul</a> i32 %X, 8
385</pre>
386</div>
387
388<p>After strength reduction:</p>
389
390<div class="doc_code">
391<pre>
392%result = <a href="#i_shl">shl</a> i32 %X, i8 3
393</pre>
394</div>
395
396<p>And the hard way:</p>
397
398<div class="doc_code">
399<pre>
400<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
401<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
402%result = <a href="#i_add">add</a> i32 %1, %1
403</pre>
404</div>
405
406<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
407important lexical features of LLVM:</p>
408
409<ol>
410
411 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
412 line.</li>
413
414 <li>Unnamed temporaries are created when the result of a computation is not
415 assigned to a named value.</li>
416
417 <li>Unnamed temporaries are numbered sequentially</li>
418
419</ol>
420
421<p>...and it also shows a convention that we follow in this document. When
422demonstrating instructions, we will follow an instruction with a comment that
423defines the type and name of value produced. Comments are shown in italic
424text.</p>
425
426</div>
427
428<!-- *********************************************************************** -->
429<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
430<!-- *********************************************************************** -->
431
432<!-- ======================================================================= -->
433<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
434</div>
435
436<div class="doc_text">
437
438<p>LLVM programs are composed of "Module"s, each of which is a
439translation unit of the input programs. Each module consists of
440functions, global variables, and symbol table entries. Modules may be
441combined together with the LLVM linker, which merges function (and
442global variable) definitions, resolves forward declarations, and merges
443symbol table entries. Here is an example of the "hello world" module:</p>
444
445<div class="doc_code">
446<pre><i>; Declare the string constant as a global constant...</i>
447<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
448 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
449
450<i>; External declaration of the puts function</i>
451<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
452
453<i>; Definition of main function</i>
454define i32 @main() { <i>; i32()* </i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]455 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]456 %cast210 = <a
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]457 href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]458
459 <i>; Call puts function to write out the string to stdout...</i>
460 <a
461 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
462 <a
463 href="#i_ret">ret</a> i32 0<br>}<br>
464</pre>
465</div>
466
467<p>This example is made up of a <a href="#globalvars">global variable</a>
468named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
469function, and a <a href="#functionstructure">function definition</a>
470for "<tt>main</tt>".</p>
471
472<p>In general, a module is made up of a list of global values,
473where both functions and global variables are global values. Global values are
474represented by a pointer to a memory location (in this case, a pointer to an
475array of char, and a pointer to a function), and have one of the following <a
476href="#linkage">linkage types</a>.</p>
477
478</div>
479
480<!-- ======================================================================= -->
481<div class="doc_subsection">
482 <a name="linkage">Linkage Types</a>
483</div>
484
485<div class="doc_text">
486
487<p>
488All Global Variables and Functions have one of the following types of linkage:
489</p>
490
491<dl>
492
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]493 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
494
495 <dd>Global values with private linkage are only directly accessible by
496 objects in the current module. In particular, linking code into a module with
497 an private global value may cause the private to be renamed as necessary to
498 avoid collisions. Because the symbol is private to the module, all
499 references can be updated. This doesn't show up in any symbol table in the
500 object file.
501 </dd>
502
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]503 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]504
Duncan Sandsa75223a2009-01-16 09:29:46 +0000[diff] [blame]505 <dd> Similar to private, but the value shows as a local symbol (STB_LOCAL in
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]506 the case of ELF) in the object file. This corresponds to the notion of the
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]507 '<tt>static</tt>' keyword in C.
508 </dd>
509
510 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
511
512 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
513 the same name when linkage occurs. This is typically used to implement
514 inline functions, templates, or other code which must be generated in each
515 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
516 allowed to be discarded.
517 </dd>
518
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]519 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
520
521 <dd>"<tt>common</tt>" linkage is exactly the same as <tt>linkonce</tt>
522 linkage, except that unreferenced <tt>common</tt> globals may not be
523 discarded. This is used for globals that may be emitted in multiple
524 translation units, but that are not guaranteed to be emitted into every
525 translation unit that uses them. One example of this is tentative
526 definitions in C, such as "<tt>int X;</tt>" at global scope.
527 </dd>
528
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]529 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
530
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]531 <dd>"<tt>weak</tt>" linkage is the same as <tt>common</tt> linkage, except
532 that some targets may choose to emit different assembly sequences for them
533 for target-dependent reasons. This is used for globals that are declared
534 "weak" in C source code.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]535 </dd>
536
537 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
538
539 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
540 pointer to array type. When two global variables with appending linkage are
541 linked together, the two global arrays are appended together. This is the
542 LLVM, typesafe, equivalent of having the system linker append together
543 "sections" with identical names when .o files are linked.
544 </dd>
545
546 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]547 <dd>The semantics of this linkage follow the ELF object file model: the
548 symbol is weak until linked, if not linked, the symbol becomes null instead
549 of being an undefined reference.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]550 </dd>
551
552 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
553
554 <dd>If none of the above identifiers are used, the global is externally
555 visible, meaning that it participates in linkage and can be used to resolve
556 external symbol references.
557 </dd>
558</dl>
559
560 <p>
561 The next two types of linkage are targeted for Microsoft Windows platform
562 only. They are designed to support importing (exporting) symbols from (to)
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]563 DLLs (Dynamic Link Libraries).
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]564 </p>
565
566 <dl>
567 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
568
569 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
570 or variable via a global pointer to a pointer that is set up by the DLL
571 exporting the symbol. On Microsoft Windows targets, the pointer name is
Dan Gohman5ec99832009-01-12 21:35:55 +0000[diff] [blame]572 formed by combining <code>__imp_</code> and the function or variable name.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]573 </dd>
574
575 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
576
577 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
578 pointer to a pointer in a DLL, so that it can be referenced with the
579 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
Dan Gohman5ec99832009-01-12 21:35:55 +0000[diff] [blame]580 name is formed by combining <code>__imp_</code> and the function or variable
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]581 name.
582 </dd>
583
584</dl>
585
Dan Gohman4dfac702008-11-24 17:18:39 +0000[diff] [blame]586<p>For example, since the "<tt>.LC0</tt>"
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]587variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
588variable and was linked with this one, one of the two would be renamed,
589preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
590external (i.e., lacking any linkage declarations), they are accessible
591outside of the current module.</p>
592<p>It is illegal for a function <i>declaration</i>
593to have any linkage type other than "externally visible", <tt>dllimport</tt>,
594or <tt>extern_weak</tt>.</p>
595<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]596linkages.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]597</div>
598
599<!-- ======================================================================= -->
600<div class="doc_subsection">
601 <a name="callingconv">Calling Conventions</a>
602</div>
603
604<div class="doc_text">
605
606<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
607and <a href="#i_invoke">invokes</a> can all have an optional calling convention
608specified for the call. The calling convention of any pair of dynamic
609caller/callee must match, or the behavior of the program is undefined. The
610following calling conventions are supported by LLVM, and more may be added in
611the future:</p>
612
613<dl>
614 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
615
616 <dd>This calling convention (the default if no other calling convention is
617 specified) matches the target C calling conventions. This calling convention
618 supports varargs function calls and tolerates some mismatch in the declared
619 prototype and implemented declaration of the function (as does normal C).
620 </dd>
621
622 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
623
624 <dd>This calling convention attempts to make calls as fast as possible
625 (e.g. by passing things in registers). This calling convention allows the
626 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]627 without having to conform to an externally specified ABI (Application Binary
628 Interface). Implementations of this convention should allow arbitrary
Arnold Schwaighofer07444922008-05-14 09:17:12 +0000[diff] [blame]629 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> to be
630 supported. This calling convention does not support varargs and requires the
631 prototype of all callees to exactly match the prototype of the function
632 definition.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]633 </dd>
634
635 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
636
637 <dd>This calling convention attempts to make code in the caller as efficient
638 as possible under the assumption that the call is not commonly executed. As
639 such, these calls often preserve all registers so that the call does not break
640 any live ranges in the caller side. This calling convention does not support
641 varargs and requires the prototype of all callees to exactly match the
642 prototype of the function definition.
643 </dd>
644
645 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
646
647 <dd>Any calling convention may be specified by number, allowing
648 target-specific calling conventions to be used. Target specific calling
649 conventions start at 64.
650 </dd>
651</dl>
652
653<p>More calling conventions can be added/defined on an as-needed basis, to
654support pascal conventions or any other well-known target-independent
655convention.</p>
656
657</div>
658
659<!-- ======================================================================= -->
660<div class="doc_subsection">
661 <a name="visibility">Visibility Styles</a>
662</div>
663
664<div class="doc_text">
665
666<p>
667All Global Variables and Functions have one of the following visibility styles:
668</p>
669
670<dl>
671 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
672
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]673 <dd>On targets that use the ELF object file format, default visibility means
674 that the declaration is visible to other
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]675 modules and, in shared libraries, means that the declared entity may be
676 overridden. On Darwin, default visibility means that the declaration is
677 visible to other modules. Default visibility corresponds to "external
678 linkage" in the language.
679 </dd>
680
681 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
682
683 <dd>Two declarations of an object with hidden visibility refer to the same
684 object if they are in the same shared object. Usually, hidden visibility
685 indicates that the symbol will not be placed into the dynamic symbol table,
686 so no other module (executable or shared library) can reference it
687 directly.
688 </dd>
689
690 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
691
692 <dd>On ELF, protected visibility indicates that the symbol will be placed in
693 the dynamic symbol table, but that references within the defining module will
694 bind to the local symbol. That is, the symbol cannot be overridden by another
695 module.
696 </dd>
697</dl>
698
699</div>
700
701<!-- ======================================================================= -->
702<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]703 <a name="namedtypes">Named Types</a>
704</div>
705
706<div class="doc_text">
707
708<p>LLVM IR allows you to specify name aliases for certain types. This can make
709it easier to read the IR and make the IR more condensed (particularly when
710recursive types are involved). An example of a name specification is:
711</p>
712
713<div class="doc_code">
714<pre>
715%mytype = type { %mytype*, i32 }
716</pre>
717</div>
718
719<p>You may give a name to any <a href="#typesystem">type</a> except "<a
720href="t_void">void</a>". Type name aliases may be used anywhere a type is
721expected with the syntax "%mytype".</p>
722
723<p>Note that type names are aliases for the structural type that they indicate,
724and that you can therefore specify multiple names for the same type. This often
725leads to confusing behavior when dumping out a .ll file. Since LLVM IR uses
726structural typing, the name is not part of the type. When printing out LLVM IR,
727the printer will pick <em>one name</em> to render all types of a particular
728shape. This means that if you have code where two different source types end up
729having the same LLVM type, that the dumper will sometimes print the "wrong" or
730unexpected type. This is an important design point and isn't going to
731change.</p>
732
733</div>
734
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]735<!-- ======================================================================= -->
736<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]737 <a name="globalvars">Global Variables</a>
738</div>
739
740<div class="doc_text">
741
742<p>Global variables define regions of memory allocated at compilation time
743instead of run-time. Global variables may optionally be initialized, may have
744an explicit section to be placed in, and may have an optional explicit alignment
745specified. A variable may be defined as "thread_local", which means that it
746will not be shared by threads (each thread will have a separated copy of the
747variable). A variable may be defined as a global "constant," which indicates
748that the contents of the variable will <b>never</b> be modified (enabling better
749optimization, allowing the global data to be placed in the read-only section of
750an executable, etc). Note that variables that need runtime initialization
751cannot be marked "constant" as there is a store to the variable.</p>
752
753<p>
754LLVM explicitly allows <em>declarations</em> of global variables to be marked
755constant, even if the final definition of the global is not. This capability
756can be used to enable slightly better optimization of the program, but requires
757the language definition to guarantee that optimizations based on the
758'constantness' are valid for the translation units that do not include the
759definition.
760</p>
761
762<p>As SSA values, global variables define pointer values that are in
763scope (i.e. they dominate) all basic blocks in the program. Global
764variables always define a pointer to their "content" type because they
765describe a region of memory, and all memory objects in LLVM are
766accessed through pointers.</p>
767
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]768<p>A global variable may be declared to reside in a target-specifc numbered
769address space. For targets that support them, address spaces may affect how
770optimizations are performed and/or what target instructions are used to access
Christopher Lamb20a39e92007-12-12 08:44:39 +0000[diff] [blame]771the variable. The default address space is zero. The address space qualifier
772must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]773
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]774<p>LLVM allows an explicit section to be specified for globals. If the target
775supports it, it will emit globals to the section specified.</p>
776
777<p>An explicit alignment may be specified for a global. If not present, or if
778the alignment is set to zero, the alignment of the global is set by the target
779to whatever it feels convenient. If an explicit alignment is specified, the
780global is forced to have at least that much alignment. All alignments must be
781a power of 2.</p>
782
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]783<p>For example, the following defines a global in a numbered address space with
784an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]785
786<div class="doc_code">
787<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]788@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]789</pre>
790</div>
791
792</div>
793
794
795<!-- ======================================================================= -->
796<div class="doc_subsection">
797 <a name="functionstructure">Functions</a>
798</div>
799
800<div class="doc_text">
801
802<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
803an optional <a href="#linkage">linkage type</a>, an optional
804<a href="#visibility">visibility style</a>, an optional
805<a href="#callingconv">calling convention</a>, a return type, an optional
806<a href="#paramattrs">parameter attribute</a> for the return type, a function
807name, a (possibly empty) argument list (each with optional
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]808<a href="#paramattrs">parameter attributes</a>), optional
809<a href="#fnattrs">function attributes</a>, an optional section,
810an optional alignment, an optional <a href="#gc">garbage collector name</a>,
Chris Lattneree202542008-10-04 18:10:21 +0000[diff] [blame]811an opening curly brace, a list of basic blocks, and a closing curly brace.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]812
813LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
814optional <a href="#linkage">linkage type</a>, an optional
815<a href="#visibility">visibility style</a>, an optional
816<a href="#callingconv">calling convention</a>, a return type, an optional
817<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]818name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksend606f5b2007-12-10 03:30:21 +0000[diff] [blame]819<a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]820
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]821<p>A function definition contains a list of basic blocks, forming the CFG
822(Control Flow Graph) for
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]823the function. Each basic block may optionally start with a label (giving the
824basic block a symbol table entry), contains a list of instructions, and ends
825with a <a href="#terminators">terminator</a> instruction (such as a branch or
826function return).</p>
827
828<p>The first basic block in a function is special in two ways: it is immediately
829executed on entrance to the function, and it is not allowed to have predecessor
830basic blocks (i.e. there can not be any branches to the entry block of a
831function). Because the block can have no predecessors, it also cannot have any
832<a href="#i_phi">PHI nodes</a>.</p>
833
834<p>LLVM allows an explicit section to be specified for functions. If the target
835supports it, it will emit functions to the section specified.</p>
836
837<p>An explicit alignment may be specified for a function. If not present, or if
838the alignment is set to zero, the alignment of the function is set by the target
839to whatever it feels convenient. If an explicit alignment is specified, the
840function is forced to have at least that much alignment. All alignments must be
841a power of 2.</p>
842
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]843 <h5>Syntax:</h5>
844
845<div class="doc_code">
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]846<tt>
847define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
848 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
849 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
850 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
851 [<a href="#gc">gc</a>] { ... }
852</tt>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]853</div>
854
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]855</div>
856
857
858<!-- ======================================================================= -->
859<div class="doc_subsection">
860 <a name="aliasstructure">Aliases</a>
861</div>
862<div class="doc_text">
863 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikov96822812008-03-22 08:36:14 +0000[diff] [blame]864 function, global variable, another alias or bitcast of global value). Aliases
865 may have an optional <a href="#linkage">linkage type</a>, and an
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]866 optional <a href="#visibility">visibility style</a>.</p>
867
868 <h5>Syntax:</h5>
869
870<div class="doc_code">
871<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]872@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]873</pre>
874</div>
875
876</div>
877
878
879
880<!-- ======================================================================= -->
881<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
882<div class="doc_text">
883 <p>The return type and each parameter of a function type may have a set of
884 <i>parameter attributes</i> associated with them. Parameter attributes are
885 used to communicate additional information about the result or parameters of
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]886 a function. Parameter attributes are considered to be part of the function,
887 not of the function type, so functions with different parameter attributes
888 can have the same function type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]889
890 <p>Parameter attributes are simple keywords that follow the type specified. If
891 multiple parameter attributes are needed, they are space separated. For
892 example:</p>
893
894<div class="doc_code">
895<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]896declare i32 @printf(i8* noalias , ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]897declare i32 @atoi(i8 zeroext)
898declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]899</pre>
900</div>
901
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]902 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
903 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]904
905 <p>Currently, only the following parameter attributes are defined:</p>
906 <dl>
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]907 <dt><tt>zeroext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]908 <dd>This indicates to the code generator that the parameter or return value
909 should be zero-extended to a 32-bit value by the caller (for a parameter)
910 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]911
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]912 <dt><tt>signext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]913 <dd>This indicates to the code generator that the parameter or return value
914 should be sign-extended to a 32-bit value by the caller (for a parameter)
915 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]916
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]917 <dt><tt>inreg</tt></dt>
Dale Johannesenc08a0e22008-09-25 20:47:45 +0000[diff] [blame]918 <dd>This indicates that this parameter or return value should be treated
919 in a special target-dependent fashion during while emitting code for a
920 function call or return (usually, by putting it in a register as opposed
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]921 to memory, though some targets use it to distinguish between two different
922 kinds of registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]923
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]924 <dt><tt><a name="byval">byval</a></tt></dt>
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]925 <dd>This indicates that the pointer parameter should really be passed by
926 value to the function. The attribute implies that a hidden copy of the
927 pointee is made between the caller and the callee, so the callee is unable
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]928 to modify the value in the callee. This attribute is only valid on LLVM
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]929 pointer arguments. It is generally used to pass structs and arrays by
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]930 value, but is also valid on pointers to scalars. The copy is considered to
931 belong to the caller not the callee (for example,
932 <tt><a href="#readonly">readonly</a></tt> functions should not write to
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]933 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnere39c5bf2009-02-05 05:42:28 +0000[diff] [blame]934 values. The byval attribute also supports specifying an alignment with the
935 align attribute. This has a target-specific effect on the code generator
936 that usually indicates a desired alignment for the synthesized stack
937 slot.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]938
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]939 <dt><tt>sret</tt></dt>
Duncan Sands616cc032008-02-18 04:19:38 +0000[diff] [blame]940 <dd>This indicates that the pointer parameter specifies the address of a
941 structure that is the return value of the function in the source program.
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]942 This pointer must be guaranteed by the caller to be valid: loads and stores
943 to the structure may be assumed by the callee to not to trap. This may only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]944 be applied to the first parameter. This is not a valid attribute for
945 return values. </dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]946
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]947 <dt><tt>noalias</tt></dt>
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]948 <dd>This indicates that the pointer does not alias any global or any other
949 parameter. The caller is responsible for ensuring that this is the
Nick Lewyckya604a942008-11-24 05:00:44 +0000[diff] [blame]950 case. On a function return value, <tt>noalias</tt> additionally indicates
951 that the pointer does not alias any other pointers visible to the
Nick Lewycky40fb6f22008-12-19 06:39:12 +0000[diff] [blame]952 caller. For further details, please see the discussion of the NoAlias
953 response in
954 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
955 analysis</a>.</dd>
956
957 <dt><tt>nocapture</tt></dt>
958 <dd>This indicates that the callee does not make any copies of the pointer
959 that outlive the callee itself. This is not a valid attribute for return
960 values.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]961
Duncan Sands4ee46812007-07-27 19:57:41 +0000[diff] [blame]962 <dt><tt>nest</tt></dt>
Duncan Sandsf1a7d4c2008-07-08 09:27:25 +0000[diff] [blame]963 <dd>This indicates that the pointer parameter can be excised using the
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]964 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
965 attribute for return values.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]966 </dl>
967
968</div>
969
970<!-- ======================================================================= -->
971<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]972 <a name="gc">Garbage Collector Names</a>
973</div>
974
975<div class="doc_text">
976<p>Each function may specify a garbage collector name, which is simply a
977string.</p>
978
979<div class="doc_code"><pre
980>define void @f() gc "name" { ...</pre></div>
981
982<p>The compiler declares the supported values of <i>name</i>. Specifying a
983collector which will cause the compiler to alter its output in order to support
984the named garbage collection algorithm.</p>
985</div>
986
987<!-- ======================================================================= -->
988<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]989 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]990</div>
991
992<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]993
994<p>Function attributes are set to communicate additional information about
995 a function. Function attributes are considered to be part of the function,
996 not of the function type, so functions with different parameter attributes
997 can have the same function type.</p>
998
999 <p>Function attributes are simple keywords that follow the type specified. If
1000 multiple attributes are needed, they are space separated. For
1001 example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1002
1003<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1004<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1005define void @f() noinline { ... }
1006define void @f() alwaysinline { ... }
1007define void @f() alwaysinline optsize { ... }
1008define void @f() optsize
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1009</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1010</div>
1011
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1012<dl>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1013<dt><tt>alwaysinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1014<dd>This attribute indicates that the inliner should attempt to inline this
1015function into callers whenever possible, ignoring any active inlining size
1016threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1017
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1018<dt><tt>noinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1019<dd>This attribute indicates that the inliner should never inline this function
Chris Lattner377f3ae2008-10-05 17:14:59 +0000[diff] [blame]1020in any situation. This attribute may not be used together with the
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1021<tt>alwaysinline</tt> attribute.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1022
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1023<dt><tt>optsize</tt></dt>
Devang Patelc29099b2008-09-29 18:34:44 +0000[diff] [blame]1024<dd>This attribute suggests that optimization passes and code generator passes
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1025make choices that keep the code size of this function low, and otherwise do
1026optimizations specifically to reduce code size.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1027
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1028<dt><tt>noreturn</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1029<dd>This function attribute indicates that the function never returns normally.
1030This produces undefined behavior at runtime if the function ever does
1031dynamically return.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1032
1033<dt><tt>nounwind</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1034<dd>This function attribute indicates that the function never returns with an
1035unwind or exceptional control flow. If the function does unwind, its runtime
1036behavior is undefined.</dd>
1037
1038<dt><tt>readnone</tt></dt>
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]1039<dd>This attribute indicates that the function computes its result (or the
1040exception it throws) based strictly on its arguments, without dereferencing any
1041pointer arguments or otherwise accessing any mutable state (e.g. memory, control
1042registers, etc) visible to caller functions. It does not write through any
1043pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments) and
1044never changes any state visible to callers.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1045
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]1046<dt><tt><a name="readonly">readonly</a></tt></dt>
1047<dd>This attribute indicates that the function does not write through any
1048pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments)
1049or otherwise modify any state (e.g. memory, control registers, etc) visible to
1050caller functions. It may dereference pointer arguments and read state that may
1051be set in the caller. A readonly function always returns the same value (or
1052throws the same exception) when called with the same set of arguments and global
1053state.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1054
1055<dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1056<dd>This attribute indicates that the function should emit a stack smashing
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1057protector. It is in the form of a "canary"&mdash;a random value placed on the
1058stack before the local variables that's checked upon return from the function to
1059see if it has been overwritten. A heuristic is used to determine if a function
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1060needs stack protectors or not.
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1061
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1062<p>If a function that has an <tt>ssp</tt> attribute is inlined into a function
1063that doesn't have an <tt>ssp</tt> attribute, then the resulting function will
1064have an <tt>ssp</tt> attribute.</p></dd>
1065
1066<dt><tt>sspreq</tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1067<dd>This attribute indicates that the function should <em>always</em> emit a
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1068stack smashing protector. This overrides the <tt><a href="#ssp">ssp</a></tt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1069function attribute.
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1070
1071<p>If a function that has an <tt>sspreq</tt> attribute is inlined into a
1072function that doesn't have an <tt>sspreq</tt> attribute or which has
1073an <tt>ssp</tt> attribute, then the resulting function will have
1074an <tt>sspreq</tt> attribute.</p></dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1075</dl>
1076
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1077</div>
1078
1079<!-- ======================================================================= -->
1080<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1081 <a name="moduleasm">Module-Level Inline Assembly</a>
1082</div>
1083
1084<div class="doc_text">
1085<p>
1086Modules may contain "module-level inline asm" blocks, which corresponds to the
1087GCC "file scope inline asm" blocks. These blocks are internally concatenated by
1088LLVM and treated as a single unit, but may be separated in the .ll file if
1089desired. The syntax is very simple:
1090</p>
1091
1092<div class="doc_code">
1093<pre>
1094module asm "inline asm code goes here"
1095module asm "more can go here"
1096</pre>
1097</div>
1098
1099<p>The strings can contain any character by escaping non-printable characters.
1100 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
1101 for the number.
1102</p>
1103
1104<p>
1105 The inline asm code is simply printed to the machine code .s file when
1106 assembly code is generated.
1107</p>
1108</div>
1109
1110<!-- ======================================================================= -->
1111<div class="doc_subsection">
1112 <a name="datalayout">Data Layout</a>
1113</div>
1114
1115<div class="doc_text">
1116<p>A module may specify a target specific data layout string that specifies how
1117data is to be laid out in memory. The syntax for the data layout is simply:</p>
1118<pre> target datalayout = "<i>layout specification</i>"</pre>
1119<p>The <i>layout specification</i> consists of a list of specifications
1120separated by the minus sign character ('-'). Each specification starts with a
1121letter and may include other information after the letter to define some
1122aspect of the data layout. The specifications accepted are as follows: </p>
1123<dl>
1124 <dt><tt>E</tt></dt>
1125 <dd>Specifies that the target lays out data in big-endian form. That is, the
1126 bits with the most significance have the lowest address location.</dd>
1127 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1128 <dd>Specifies that the target lays out data in little-endian form. That is,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1129 the bits with the least significance have the lowest address location.</dd>
1130 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1131 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
1132 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
1133 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
1134 too.</dd>
1135 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1136 <dd>This specifies the alignment for an integer type of a given bit
1137 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1138 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1139 <dd>This specifies the alignment for a vector type of a given bit
1140 <i>size</i>.</dd>
1141 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1142 <dd>This specifies the alignment for a floating point type of a given bit
1143 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1144 (double).</dd>
1145 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1146 <dd>This specifies the alignment for an aggregate type of a given bit
1147 <i>size</i>.</dd>
1148</dl>
1149<p>When constructing the data layout for a given target, LLVM starts with a
1150default set of specifications which are then (possibly) overriden by the
1151specifications in the <tt>datalayout</tt> keyword. The default specifications
1152are given in this list:</p>
1153<ul>
1154 <li><tt>E</tt> - big endian</li>
1155 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1156 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1157 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1158 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1159 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1160 <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]1161 alignment of 64-bits</li>
1162 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1163 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1164 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1165 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1166 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
1167</ul>
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]1168<p>When LLVM is determining the alignment for a given type, it uses the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1169following rules:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1170<ol>
1171 <li>If the type sought is an exact match for one of the specifications, that
1172 specification is used.</li>
1173 <li>If no match is found, and the type sought is an integer type, then the
1174 smallest integer type that is larger than the bitwidth of the sought type is
1175 used. If none of the specifications are larger than the bitwidth then the the
1176 largest integer type is used. For example, given the default specifications
1177 above, the i7 type will use the alignment of i8 (next largest) while both
1178 i65 and i256 will use the alignment of i64 (largest specified).</li>
1179 <li>If no match is found, and the type sought is a vector type, then the
1180 largest vector type that is smaller than the sought vector type will be used
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1181 as a fall back. This happens because &lt;128 x double&gt; can be implemented
1182 in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1183</ol>
1184</div>
1185
1186<!-- *********************************************************************** -->
1187<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1188<!-- *********************************************************************** -->
1189
1190<div class="doc_text">
1191
1192<p>The LLVM type system is one of the most important features of the
1193intermediate representation. Being typed enables a number of
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1194optimizations to be performed on the intermediate representation directly,
1195without having to do
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1196extra analyses on the side before the transformation. A strong type
1197system makes it easier to read the generated code and enables novel
1198analyses and transformations that are not feasible to perform on normal
1199three address code representations.</p>
1200
1201</div>
1202
1203<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1204<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1205Classifications</a> </div>
1206<div class="doc_text">
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1207<p>The types fall into a few useful
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1208classifications:</p>
1209
1210<table border="1" cellspacing="0" cellpadding="4">
1211 <tbody>
1212 <tr><th>Classification</th><th>Types</th></tr>
1213 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1214 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1215 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1216 </tr>
1217 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1218 <td><a href="#t_floating">floating point</a></td>
1219 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1220 </tr>
1221 <tr>
1222 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1223 <td><a href="#t_integer">integer</a>,
1224 <a href="#t_floating">floating point</a>,
1225 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1226 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1227 <a href="#t_struct">structure</a>,
1228 <a href="#t_array">array</a>,
Dan Gohmand13951e2008-05-23 22:50:26 +0000[diff] [blame]1229 <a href="#t_label">label</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1230 </td>
1231 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1232 <tr>
1233 <td><a href="#t_primitive">primitive</a></td>
1234 <td><a href="#t_label">label</a>,
1235 <a href="#t_void">void</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1236 <a href="#t_floating">floating point</a>.</td>
1237 </tr>
1238 <tr>
1239 <td><a href="#t_derived">derived</a></td>
1240 <td><a href="#t_integer">integer</a>,
1241 <a href="#t_array">array</a>,
1242 <a href="#t_function">function</a>,
1243 <a href="#t_pointer">pointer</a>,
1244 <a href="#t_struct">structure</a>,
1245 <a href="#t_pstruct">packed structure</a>,
1246 <a href="#t_vector">vector</a>,
1247 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1248 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1249 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1250 </tbody>
1251</table>
1252
1253<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1254most important. Values of these types are the only ones which can be
1255produced by instructions, passed as arguments, or used as operands to
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]1256instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1257</div>
1258
1259<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1260<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1261
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1262<div class="doc_text">
1263<p>The primitive types are the fundamental building blocks of the LLVM
1264system.</p>
1265
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1266</div>
1267
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1268<!-- _______________________________________________________________________ -->
1269<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1270
1271<div class="doc_text">
1272 <table>
1273 <tbody>
1274 <tr><th>Type</th><th>Description</th></tr>
1275 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1276 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1277 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1278 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1279 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1280 </tbody>
1281 </table>
1282</div>
1283
1284<!-- _______________________________________________________________________ -->
1285<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1286
1287<div class="doc_text">
1288<h5>Overview:</h5>
1289<p>The void type does not represent any value and has no size.</p>
1290
1291<h5>Syntax:</h5>
1292
1293<pre>
1294 void
1295</pre>
1296</div>
1297
1298<!-- _______________________________________________________________________ -->
1299<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1300
1301<div class="doc_text">
1302<h5>Overview:</h5>
1303<p>The label type represents code labels.</p>
1304
1305<h5>Syntax:</h5>
1306
1307<pre>
1308 label
1309</pre>
1310</div>
1311
1312
1313<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1314<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1315
1316<div class="doc_text">
1317
1318<p>The real power in LLVM comes from the derived types in the system.
1319This is what allows a programmer to represent arrays, functions,
1320pointers, and other useful types. Note that these derived types may be
1321recursive: For example, it is possible to have a two dimensional array.</p>
1322
1323</div>
1324
1325<!-- _______________________________________________________________________ -->
1326<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1327
1328<div class="doc_text">
1329
1330<h5>Overview:</h5>
1331<p>The integer type is a very simple derived type that simply specifies an
1332arbitrary bit width for the integer type desired. Any bit width from 1 bit to
13332^23-1 (about 8 million) can be specified.</p>
1334
1335<h5>Syntax:</h5>
1336
1337<pre>
1338 iN
1339</pre>
1340
1341<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1342value.</p>
1343
1344<h5>Examples:</h5>
1345<table class="layout">
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1346 <tbody>
1347 <tr>
1348 <td><tt>i1</tt></td>
1349 <td>a single-bit integer.</td>
1350 </tr><tr>
1351 <td><tt>i32</tt></td>
1352 <td>a 32-bit integer.</td>
1353 </tr><tr>
1354 <td><tt>i1942652</tt></td>
1355 <td>a really big integer of over 1 million bits.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1356 </tr>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1357 </tbody>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1358</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1359
1360<p>Note that the code generator does not yet support large integer types
1361to be used as function return types. The specific limit on how large a
1362return type the code generator can currently handle is target-dependent;
1363currently it's often 64 bits for 32-bit targets and 128 bits for 64-bit
1364targets.</p>
1365
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1366</div>
1367
1368<!-- _______________________________________________________________________ -->
1369<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1370
1371<div class="doc_text">
1372
1373<h5>Overview:</h5>
1374
1375<p>The array type is a very simple derived type that arranges elements
1376sequentially in memory. The array type requires a size (number of
1377elements) and an underlying data type.</p>
1378
1379<h5>Syntax:</h5>
1380
1381<pre>
1382 [&lt;# elements&gt; x &lt;elementtype&gt;]
1383</pre>
1384
1385<p>The number of elements is a constant integer value; elementtype may
1386be any type with a size.</p>
1387
1388<h5>Examples:</h5>
1389<table class="layout">
1390 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1391 <td class="left"><tt>[40 x i32]</tt></td>
1392 <td class="left">Array of 40 32-bit integer values.</td>
1393 </tr>
1394 <tr class="layout">
1395 <td class="left"><tt>[41 x i32]</tt></td>
1396 <td class="left">Array of 41 32-bit integer values.</td>
1397 </tr>
1398 <tr class="layout">
1399 <td class="left"><tt>[4 x i8]</tt></td>
1400 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1401 </tr>
1402</table>
1403<p>Here are some examples of multidimensional arrays:</p>
1404<table class="layout">
1405 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1406 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1407 <td class="left">3x4 array of 32-bit integer values.</td>
1408 </tr>
1409 <tr class="layout">
1410 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1411 <td class="left">12x10 array of single precision floating point values.</td>
1412 </tr>
1413 <tr class="layout">
1414 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1415 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1416 </tr>
1417</table>
1418
1419<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1420length array. Normally, accesses past the end of an array are undefined in
1421LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1422As a special case, however, zero length arrays are recognized to be variable
1423length. This allows implementation of 'pascal style arrays' with the LLVM
1424type "{ i32, [0 x float]}", for example.</p>
1425
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1426<p>Note that the code generator does not yet support large aggregate types
1427to be used as function return types. The specific limit on how large an
1428aggregate return type the code generator can currently handle is
1429target-dependent, and also dependent on the aggregate element types.</p>
1430
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1431</div>
1432
1433<!-- _______________________________________________________________________ -->
1434<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
1435<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1436
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1437<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1438
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1439<p>The function type can be thought of as a function signature. It
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1440consists of a return type and a list of formal parameter types. The
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1441return 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]1442If 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]1443class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1444
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1445<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1446
1447<pre>
1448 &lt;returntype list&gt; (&lt;parameter list&gt;)
1449</pre>
1450
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1451<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
1452specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1453which indicates that the function takes a variable number of arguments.
1454Variable argument functions can access their arguments with the <a
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1455 href="#int_varargs">variable argument handling intrinsic</a> functions.
1456'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1457<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1458
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1459<h5>Examples:</h5>
1460<table class="layout">
1461 <tr class="layout">
1462 <td class="left"><tt>i32 (i32)</tt></td>
1463 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1464 </td>
1465 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1466 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1467 </tt></td>
1468 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1469 an <tt>i16</tt> that should be sign extended and a
1470 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1471 <tt>float</tt>.
1472 </td>
1473 </tr><tr class="layout">
1474 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1475 <td class="left">A vararg function that takes at least one
1476 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1477 which returns an integer. This is the signature for <tt>printf</tt> in
1478 LLVM.
1479 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1480 </tr><tr class="layout">
1481 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Misha Brukmanafc88b02008-11-27 06:41:20 +0000[diff] [blame]1482 <td class="left">A function taking an <tt>i32</tt>, returning two
1483 <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1484 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1485 </tr>
1486</table>
1487
1488</div>
1489<!-- _______________________________________________________________________ -->
1490<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
1491<div class="doc_text">
1492<h5>Overview:</h5>
1493<p>The structure type is used to represent a collection of data members
1494together in memory. The packing of the field types is defined to match
1495the ABI of the underlying processor. The elements of a structure may
1496be any type that has a size.</p>
1497<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1498and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1499field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1500instruction.</p>
1501<h5>Syntax:</h5>
1502<pre> { &lt;type list&gt; }<br></pre>
1503<h5>Examples:</h5>
1504<table class="layout">
1505 <tr class="layout">
1506 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1507 <td class="left">A triple of three <tt>i32</tt> values</td>
1508 </tr><tr class="layout">
1509 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1510 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1511 second element is a <a href="#t_pointer">pointer</a> to a
1512 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1513 an <tt>i32</tt>.</td>
1514 </tr>
1515</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1516
1517<p>Note that the code generator does not yet support large aggregate types
1518to be used as function return types. The specific limit on how large an
1519aggregate return type the code generator can currently handle is
1520target-dependent, and also dependent on the aggregate element types.</p>
1521
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1522</div>
1523
1524<!-- _______________________________________________________________________ -->
1525<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1526</div>
1527<div class="doc_text">
1528<h5>Overview:</h5>
1529<p>The packed structure type is used to represent a collection of data members
1530together in memory. There is no padding between fields. Further, the alignment
1531of a packed structure is 1 byte. The elements of a packed structure may
1532be any type that has a size.</p>
1533<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1534and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1535field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1536instruction.</p>
1537<h5>Syntax:</h5>
1538<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1539<h5>Examples:</h5>
1540<table class="layout">
1541 <tr class="layout">
1542 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1543 <td class="left">A triple of three <tt>i32</tt> values</td>
1544 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1545 <td class="left">
1546<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1547 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1548 second element is a <a href="#t_pointer">pointer</a> to a
1549 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1550 an <tt>i32</tt>.</td>
1551 </tr>
1552</table>
1553</div>
1554
1555<!-- _______________________________________________________________________ -->
1556<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
1557<div class="doc_text">
1558<h5>Overview:</h5>
1559<p>As in many languages, the pointer type represents a pointer or
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]1560reference to another object, which must live in memory. Pointer types may have
1561an optional address space attribute defining the target-specific numbered
1562address space where the pointed-to object resides. The default address space is
1563zero.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1564<h5>Syntax:</h5>
1565<pre> &lt;type&gt; *<br></pre>
1566<h5>Examples:</h5>
1567<table class="layout">
1568 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1569 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1570 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1571 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1572 </tr>
1573 <tr class="layout">
1574 <td class="left"><tt>i32 (i32 *) *</tt></td>
1575 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1576 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1577 <tt>i32</tt>.</td>
1578 </tr>
1579 <tr class="layout">
1580 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1581 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1582 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1583 </tr>
1584</table>
1585</div>
1586
1587<!-- _______________________________________________________________________ -->
1588<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
1589<div class="doc_text">
1590
1591<h5>Overview:</h5>
1592
1593<p>A vector type is a simple derived type that represents a vector
1594of elements. Vector types are used when multiple primitive data
1595are operated in parallel using a single instruction (SIMD).
1596A vector type requires a size (number of
1597elements) and an underlying primitive data type. Vectors must have a power
1598of two length (1, 2, 4, 8, 16 ...). Vector types are
1599considered <a href="#t_firstclass">first class</a>.</p>
1600
1601<h5>Syntax:</h5>
1602
1603<pre>
1604 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1605</pre>
1606
1607<p>The number of elements is a constant integer value; elementtype may
1608be any integer or floating point type.</p>
1609
1610<h5>Examples:</h5>
1611
1612<table class="layout">
1613 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1614 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1615 <td class="left">Vector of 4 32-bit integer values.</td>
1616 </tr>
1617 <tr class="layout">
1618 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1619 <td class="left">Vector of 8 32-bit floating-point values.</td>
1620 </tr>
1621 <tr class="layout">
1622 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1623 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1624 </tr>
1625</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1626
1627<p>Note that the code generator does not yet support large vector types
1628to be used as function return types. The specific limit on how large a
1629vector return type codegen can currently handle is target-dependent;
1630currently it's often a few times longer than a hardware vector register.</p>
1631
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1632</div>
1633
1634<!-- _______________________________________________________________________ -->
1635<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1636<div class="doc_text">
1637
1638<h5>Overview:</h5>
1639
1640<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksenda0706e2007-10-14 00:34:53 +0000[diff] [blame]1641corresponds (for example) to the C notion of a forward declared structure type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1642In LLVM, opaque types can eventually be resolved to any type (not just a
1643structure type).</p>
1644
1645<h5>Syntax:</h5>
1646
1647<pre>
1648 opaque
1649</pre>
1650
1651<h5>Examples:</h5>
1652
1653<table class="layout">
1654 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1655 <td class="left"><tt>opaque</tt></td>
1656 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1657 </tr>
1658</table>
1659</div>
1660
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1661<!-- ======================================================================= -->
1662<div class="doc_subsection">
1663 <a name="t_uprefs">Type Up-references</a>
1664</div>
1665
1666<div class="doc_text">
1667<h5>Overview:</h5>
1668<p>
1669An "up reference" allows you to refer to a lexically enclosing type without
1670requiring it to have a name. For instance, a structure declaration may contain a
1671pointer to any of the types it is lexically a member of. Example of up
1672references (with their equivalent as named type declarations) include:</p>
1673
1674<pre>
1675 { \2 * } %x = type { %t* }
1676 { \2 }* %y = type { %y }*
1677 \1* %z = type %z*
1678</pre>
1679
1680<p>
1681An up reference is needed by the asmprinter for printing out cyclic types when
1682there is no declared name for a type in the cycle. Because the asmprinter does
1683not want to print out an infinite type string, it needs a syntax to handle
1684recursive types that have no names (all names are optional in llvm IR).
1685</p>
1686
1687<h5>Syntax:</h5>
1688<pre>
1689 \&lt;level&gt;
1690</pre>
1691
1692<p>
1693The level is the count of the lexical type that is being referred to.
1694</p>
1695
1696<h5>Examples:</h5>
1697
1698<table class="layout">
1699 <tr class="layout">
1700 <td class="left"><tt>\1*</tt></td>
1701 <td class="left">Self-referential pointer.</td>
1702 </tr>
1703 <tr class="layout">
1704 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1705 <td class="left">Recursive structure where the upref refers to the out-most
1706 structure.</td>
1707 </tr>
1708</table>
1709</div>
1710
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1711
1712<!-- *********************************************************************** -->
1713<div class="doc_section"> <a name="constants">Constants</a> </div>
1714<!-- *********************************************************************** -->
1715
1716<div class="doc_text">
1717
1718<p>LLVM has several different basic types of constants. This section describes
1719them all and their syntax.</p>
1720
1721</div>
1722
1723<!-- ======================================================================= -->
1724<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1725
1726<div class="doc_text">
1727
1728<dl>
1729 <dt><b>Boolean constants</b></dt>
1730
1731 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1732 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
1733 </dd>
1734
1735 <dt><b>Integer constants</b></dt>
1736
1737 <dd>Standard integers (such as '4') are constants of the <a
1738 href="#t_integer">integer</a> type. Negative numbers may be used with
1739 integer types.
1740 </dd>
1741
1742 <dt><b>Floating point constants</b></dt>
1743
1744 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1745 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]1746 notation (see below). The assembler requires the exact decimal value of
1747 a floating-point constant. For example, the assembler accepts 1.25 but
1748 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1749 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1750
1751 <dt><b>Null pointer constants</b></dt>
1752
1753 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
1754 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1755
1756</dl>
1757
1758<p>The one non-intuitive notation for constants is the optional hexadecimal form
1759of floating point constants. For example, the form '<tt>double
17600x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
17614.5e+15</tt>'. The only time hexadecimal floating point constants are required
1762(and the only time that they are generated by the disassembler) is when a
1763floating point constant must be emitted but it cannot be represented as a
1764decimal floating point number. For example, NaN's, infinities, and other
1765special values are represented in their IEEE hexadecimal format so that
1766assembly and disassembly do not cause any bits to change in the constants.</p>
1767
1768</div>
1769
1770<!-- ======================================================================= -->
1771<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1772</div>
1773
1774<div class="doc_text">
1775<p>Aggregate constants arise from aggregation of simple constants
1776and smaller aggregate constants.</p>
1777
1778<dl>
1779 <dt><b>Structure constants</b></dt>
1780
1781 <dd>Structure constants are represented with notation similar to structure
1782 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner6c8de962007-12-25 20:34:52 +0000[diff] [blame]1783 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1784 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]1785 must have <a href="#t_struct">structure type</a>, and the number and
1786 types of elements must match those specified by the type.
1787 </dd>
1788
1789 <dt><b>Array constants</b></dt>
1790
1791 <dd>Array constants are represented with notation similar to array type
1792 definitions (a comma separated list of elements, surrounded by square brackets
1793 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
1794 constants must have <a href="#t_array">array type</a>, and the number and
1795 types of elements must match those specified by the type.
1796 </dd>
1797
1798 <dt><b>Vector constants</b></dt>
1799
1800 <dd>Vector constants are represented with notation similar to vector type
1801 definitions (a comma separated list of elements, surrounded by
1802 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1803 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
1804 href="#t_vector">vector type</a>, and the number and types of elements must
1805 match those specified by the type.
1806 </dd>
1807
1808 <dt><b>Zero initialization</b></dt>
1809
1810 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1811 value to zero of <em>any</em> type, including scalar and aggregate types.
1812 This is often used to avoid having to print large zero initializers (e.g. for
1813 large arrays) and is always exactly equivalent to using explicit zero
1814 initializers.
1815 </dd>
1816</dl>
1817
1818</div>
1819
1820<!-- ======================================================================= -->
1821<div class="doc_subsection">
1822 <a name="globalconstants">Global Variable and Function Addresses</a>
1823</div>
1824
1825<div class="doc_text">
1826
1827<p>The addresses of <a href="#globalvars">global variables</a> and <a
1828href="#functionstructure">functions</a> are always implicitly valid (link-time)
1829constants. These constants are explicitly referenced when the <a
1830href="#identifiers">identifier for the global</a> is used and always have <a
1831href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1832file:</p>
1833
1834<div class="doc_code">
1835<pre>
1836@X = global i32 17
1837@Y = global i32 42
1838@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
1839</pre>
1840</div>
1841
1842</div>
1843
1844<!-- ======================================================================= -->
1845<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
1846<div class="doc_text">
1847 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
1848 no specific value. Undefined values may be of any type and be used anywhere
1849 a constant is permitted.</p>
1850
1851 <p>Undefined values indicate to the compiler that the program is well defined
1852 no matter what value is used, giving the compiler more freedom to optimize.
1853 </p>
1854</div>
1855
1856<!-- ======================================================================= -->
1857<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1858</div>
1859
1860<div class="doc_text">
1861
1862<p>Constant expressions are used to allow expressions involving other constants
1863to be used as constants. Constant expressions may be of any <a
1864href="#t_firstclass">first class</a> type and may involve any LLVM operation
1865that does not have side effects (e.g. load and call are not supported). The
1866following is the syntax for constant expressions:</p>
1867
1868<dl>
1869 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1870 <dd>Truncate a constant to another type. The bit size of CST must be larger
1871 than the bit size of TYPE. Both types must be integers.</dd>
1872
1873 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1874 <dd>Zero extend a constant to another type. The bit size of CST must be
1875 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1876
1877 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1878 <dd>Sign extend a constant to another type. The bit size of CST must be
1879 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1880
1881 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1882 <dd>Truncate a floating point constant to another floating point type. The
1883 size of CST must be larger than the size of TYPE. Both types must be
1884 floating point.</dd>
1885
1886 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1887 <dd>Floating point extend a constant to another type. The size of CST must be
1888 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1889
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]1890 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1891 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1892 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1893 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1894 of the same number of elements. If the value won't fit in the integer type,
1895 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1896
1897 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
1898 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1899 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1900 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1901 of the same number of elements. If the value won't fit in the integer type,
1902 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1903
1904 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
1905 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1906 constant. TYPE must be a scalar or vector floating point type. CST must be of
1907 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1908 of the same number of elements. If the value won't fit in the floating point
1909 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1910
1911 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
1912 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1913 constant. TYPE must be a scalar or vector floating point type. CST must be of
1914 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1915 of the same number of elements. If the value won't fit in the floating point
1916 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1917
1918 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1919 <dd>Convert a pointer typed constant to the corresponding integer constant
1920 TYPE must be an integer type. CST must be of pointer type. The CST value is
1921 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1922
1923 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1924 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1925 pointer type. CST must be of integer type. The CST value is zero extended,
1926 truncated, or unchanged to make it fit in a pointer size. This one is
1927 <i>really</i> dangerous!</dd>
1928
1929 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
1930 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1931 identical (same number of bits). The conversion is done as if the CST value
1932 was stored to memory and read back as TYPE. In other words, no bits change
1933 with this operator, just the type. This can be used for conversion of
1934 vector types to any other type, as long as they have the same bit width. For
Dan Gohman7305fa02008-09-08 16:45:59 +0000[diff] [blame]1935 pointers it is only valid to cast to another pointer type. It is not valid
1936 to bitcast to or from an aggregate type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1937 </dd>
1938
1939 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1940
1941 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1942 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1943 instruction, the index list may have zero or more indexes, which are required
1944 to make sense for the type of "CSTPTR".</dd>
1945
1946 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1947
1948 <dd>Perform the <a href="#i_select">select operation</a> on
1949 constants.</dd>
1950
1951 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1952 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1953
1954 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1955 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
1956
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]1957 <dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
1958 <dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
1959
1960 <dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
1961 <dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
1962
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1963 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1964
1965 <dd>Perform the <a href="#i_extractelement">extractelement
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1966 operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1967
1968 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1969
1970 <dd>Perform the <a href="#i_insertelement">insertelement
1971 operation</a> on constants.</dd>
1972
1973
1974 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1975
1976 <dd>Perform the <a href="#i_shufflevector">shufflevector
1977 operation</a> on constants.</dd>
1978
1979 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1980
1981 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1982 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
1983 binary</a> operations. The constraints on operands are the same as those for
1984 the corresponding instruction (e.g. no bitwise operations on floating point
1985 values are allowed).</dd>
1986</dl>
1987</div>
1988
1989<!-- *********************************************************************** -->
1990<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1991<!-- *********************************************************************** -->
1992
1993<!-- ======================================================================= -->
1994<div class="doc_subsection">
1995<a name="inlineasm">Inline Assembler Expressions</a>
1996</div>
1997
1998<div class="doc_text">
1999
2000<p>
2001LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
2002Module-Level Inline Assembly</a>) through the use of a special value. This
2003value represents the inline assembler as a string (containing the instructions
2004to emit), a list of operand constraints (stored as a string), and a flag that
2005indicates whether or not the inline asm expression has side effects. An example
2006inline assembler expression is:
2007</p>
2008
2009<div class="doc_code">
2010<pre>
2011i32 (i32) asm "bswap $0", "=r,r"
2012</pre>
2013</div>
2014
2015<p>
2016Inline assembler expressions may <b>only</b> be used as the callee operand of
2017a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
2018</p>
2019
2020<div class="doc_code">
2021<pre>
2022%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2023</pre>
2024</div>
2025
2026<p>
2027Inline asms with side effects not visible in the constraint list must be marked
2028as having side effects. This is done through the use of the
2029'<tt>sideeffect</tt>' keyword, like so:
2030</p>
2031
2032<div class="doc_code">
2033<pre>
2034call void asm sideeffect "eieio", ""()
2035</pre>
2036</div>
2037
2038<p>TODO: The format of the asm and constraints string still need to be
2039documented here. Constraints on what can be done (e.g. duplication, moving, etc
Chris Lattner1cdd64e2008-10-04 18:36:02 +0000[diff] [blame]2040need to be documented). This is probably best done by reference to another
2041document that covers inline asm from a holistic perspective.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2042</p>
2043
2044</div>
2045
2046<!-- *********************************************************************** -->
2047<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2048<!-- *********************************************************************** -->
2049
2050<div class="doc_text">
2051
2052<p>The LLVM instruction set consists of several different
2053classifications of instructions: <a href="#terminators">terminator
2054instructions</a>, <a href="#binaryops">binary instructions</a>,
2055<a href="#bitwiseops">bitwise binary instructions</a>, <a
2056 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
2057instructions</a>.</p>
2058
2059</div>
2060
2061<!-- ======================================================================= -->
2062<div class="doc_subsection"> <a name="terminators">Terminator
2063Instructions</a> </div>
2064
2065<div class="doc_text">
2066
2067<p>As mentioned <a href="#functionstructure">previously</a>, every
2068basic block in a program ends with a "Terminator" instruction, which
2069indicates which block should be executed after the current block is
2070finished. These terminator instructions typically yield a '<tt>void</tt>'
2071value: they produce control flow, not values (the one exception being
2072the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2073<p>There are six different terminator instructions: the '<a
2074 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
2075instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
2076the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
2077 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
2078 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
2079
2080</div>
2081
2082<!-- _______________________________________________________________________ -->
2083<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2084Instruction</a> </div>
2085<div class="doc_text">
2086<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2087<pre>
2088 ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2089 ret void <i>; Return from void function</i>
2090</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2091
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2092<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2093
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2094<p>The '<tt>ret</tt>' instruction is used to return control flow (and
2095optionally a value) from a function back to the caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2096<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2097returns a value and then causes control flow, and one that just causes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2098control flow to occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2099
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2100<h5>Arguments:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2101
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2102<p>The '<tt>ret</tt>' instruction optionally accepts a single argument,
2103the return value. The type of the return value must be a
2104'<a href="#t_firstclass">first class</a>' type.</p>
2105
2106<p>A function is not <a href="#wellformed">well formed</a> if
2107it it has a non-void return type and contains a '<tt>ret</tt>'
2108instruction with no return value or a return value with a type that
2109does not match its type, or if it has a void return type and contains
2110a '<tt>ret</tt>' instruction with a return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2111
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2112<h5>Semantics:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2113
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2114<p>When the '<tt>ret</tt>' instruction is executed, control flow
2115returns back to the calling function's context. If the caller is a "<a
2116 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
2117the instruction after the call. If the caller was an "<a
2118 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
2119at the beginning of the "normal" destination block. If the instruction
2120returns a value, that value shall set the call or invoke instruction's
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2121return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2122
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2123<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2124
2125<pre>
2126 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2127 ret void <i>; Return from a void function</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2128 ret { i32, i8 } { i32 4, i8 2 } <i>; Return an aggregate of values 4 and 2</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2129</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2130
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]2131<p>Note that the code generator does not yet fully support large
2132 return values. The specific sizes that are currently supported are
2133 dependent on the target. For integers, on 32-bit targets the limit
2134 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2135 For aggregate types, the current limits are dependent on the element
2136 types; for example targets are often limited to 2 total integer
2137 elements and 2 total floating-point elements.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2138
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2139</div>
2140<!-- _______________________________________________________________________ -->
2141<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
2142<div class="doc_text">
2143<h5>Syntax:</h5>
2144<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
2145</pre>
2146<h5>Overview:</h5>
2147<p>The '<tt>br</tt>' instruction is used to cause control flow to
2148transfer to a different basic block in the current function. There are
2149two forms of this instruction, corresponding to a conditional branch
2150and an unconditional branch.</p>
2151<h5>Arguments:</h5>
2152<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
2153single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
2154unconditional form of the '<tt>br</tt>' instruction takes a single
2155'<tt>label</tt>' value as a target.</p>
2156<h5>Semantics:</h5>
2157<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
2158argument is evaluated. If the value is <tt>true</tt>, control flows
2159to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2160control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2161<h5>Example:</h5>
2162<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
2163 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
2164</div>
2165<!-- _______________________________________________________________________ -->
2166<div class="doc_subsubsection">
2167 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2168</div>
2169
2170<div class="doc_text">
2171<h5>Syntax:</h5>
2172
2173<pre>
2174 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2175</pre>
2176
2177<h5>Overview:</h5>
2178
2179<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
2180several different places. It is a generalization of the '<tt>br</tt>'
2181instruction, allowing a branch to occur to one of many possible
2182destinations.</p>
2183
2184
2185<h5>Arguments:</h5>
2186
2187<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
2188comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
2189an array of pairs of comparison value constants and '<tt>label</tt>'s. The
2190table is not allowed to contain duplicate constant entries.</p>
2191
2192<h5>Semantics:</h5>
2193
2194<p>The <tt>switch</tt> instruction specifies a table of values and
2195destinations. When the '<tt>switch</tt>' instruction is executed, this
2196table is searched for the given value. If the value is found, control flow is
2197transfered to the corresponding destination; otherwise, control flow is
2198transfered to the default destination.</p>
2199
2200<h5>Implementation:</h5>
2201
2202<p>Depending on properties of the target machine and the particular
2203<tt>switch</tt> instruction, this instruction may be code generated in different
2204ways. For example, it could be generated as a series of chained conditional
2205branches or with a lookup table.</p>
2206
2207<h5>Example:</h5>
2208
2209<pre>
2210 <i>; Emulate a conditional br instruction</i>
2211 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2212 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2213
2214 <i>; Emulate an unconditional br instruction</i>
2215 switch i32 0, label %dest [ ]
2216
2217 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2218 switch i32 %val, label %otherwise [ i32 0, label %onzero
2219 i32 1, label %onone
2220 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2221</pre>
2222</div>
2223
2224<!-- _______________________________________________________________________ -->
2225<div class="doc_subsubsection">
2226 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2227</div>
2228
2229<div class="doc_text">
2230
2231<h5>Syntax:</h5>
2232
2233<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2234 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ptr to function ty&gt; &lt;function ptr val&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2235 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2236</pre>
2237
2238<h5>Overview:</h5>
2239
2240<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
2241function, with the possibility of control flow transfer to either the
2242'<tt>normal</tt>' label or the
2243'<tt>exception</tt>' label. If the callee function returns with the
2244"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
2245"normal" label. If the callee (or any indirect callees) returns with the "<a
2246href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2247continued at the dynamically nearest "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2248
2249<h5>Arguments:</h5>
2250
2251<p>This instruction requires several arguments:</p>
2252
2253<ol>
2254 <li>
2255 The optional "cconv" marker indicates which <a href="#callingconv">calling
2256 convention</a> the call should use. If none is specified, the call defaults
2257 to using C calling conventions.
2258 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2259
2260 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
2261 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
2262 and '<tt>inreg</tt>' attributes are valid here.</li>
2263
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2264 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
2265 function value being invoked. In most cases, this is a direct function
2266 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
2267 an arbitrary pointer to function value.
2268 </li>
2269
2270 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
2271 function to be invoked. </li>
2272
2273 <li>'<tt>function args</tt>': argument list whose types match the function
2274 signature argument types. If the function signature indicates the function
2275 accepts a variable number of arguments, the extra arguments can be
2276 specified. </li>
2277
2278 <li>'<tt>normal label</tt>': the label reached when the called function
2279 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2280
2281 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2282 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2283
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2284 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2285 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2286 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2287</ol>
2288
2289<h5>Semantics:</h5>
2290
2291<p>This instruction is designed to operate as a standard '<tt><a
2292href="#i_call">call</a></tt>' instruction in most regards. The primary
2293difference is that it establishes an association with a label, which is used by
2294the runtime library to unwind the stack.</p>
2295
2296<p>This instruction is used in languages with destructors to ensure that proper
2297cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2298exception. Additionally, this is important for implementation of
2299'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2300
2301<h5>Example:</h5>
2302<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2303 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2304 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2305 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2306 unwind label %TestCleanup <i>; {i32}:retval set</i>
2307</pre>
2308</div>
2309
2310
2311<!-- _______________________________________________________________________ -->
2312
2313<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2314Instruction</a> </div>
2315
2316<div class="doc_text">
2317
2318<h5>Syntax:</h5>
2319<pre>
2320 unwind
2321</pre>
2322
2323<h5>Overview:</h5>
2324
2325<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2326at the first callee in the dynamic call stack which used an <a
2327href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2328primarily used to implement exception handling.</p>
2329
2330<h5>Semantics:</h5>
2331
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2332<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2333immediately halt. The dynamic call stack is then searched for the first <a
2334href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2335execution continues at the "exceptional" destination block specified by the
2336<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2337dynamic call chain, undefined behavior results.</p>
2338</div>
2339
2340<!-- _______________________________________________________________________ -->
2341
2342<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2343Instruction</a> </div>
2344
2345<div class="doc_text">
2346
2347<h5>Syntax:</h5>
2348<pre>
2349 unreachable
2350</pre>
2351
2352<h5>Overview:</h5>
2353
2354<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2355instruction is used to inform the optimizer that a particular portion of the
2356code is not reachable. This can be used to indicate that the code after a
2357no-return function cannot be reached, and other facts.</p>
2358
2359<h5>Semantics:</h5>
2360
2361<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2362</div>
2363
2364
2365
2366<!-- ======================================================================= -->
2367<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
2368<div class="doc_text">
2369<p>Binary operators are used to do most of the computation in a
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2370program. They require two operands of the same type, execute an operation on them, and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2371produce a single value. The operands might represent
2372multiple 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]2373The result value has the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2374<p>There are several different binary operators:</p>
2375</div>
2376<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2377<div class="doc_subsubsection">
2378 <a name="i_add">'<tt>add</tt>' Instruction</a>
2379</div>
2380
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2381<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2382
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2383<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2384
2385<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2386 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2387</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2388
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2389<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2390
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2391<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2392
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2393<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2394
2395<p>The two arguments to the '<tt>add</tt>' instruction must be <a
2396 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
2397 <a href="#t_vector">vector</a> values. Both arguments must have identical
2398 types.</p>
2399
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2400<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2401
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2402<p>The value produced is the integer or floating point sum of the two
2403operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2404
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2405<p>If an integer sum has unsigned overflow, the result returned is the
2406mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2407the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2408
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2409<p>Because LLVM integers use a two's complement representation, this
2410instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2411
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2412<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2413
2414<pre>
2415 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2416</pre>
2417</div>
2418<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2419<div class="doc_subsubsection">
2420 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2421</div>
2422
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2423<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2424
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2425<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2426
2427<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2428 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2429</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2430
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2431<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2432
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2433<p>The '<tt>sub</tt>' instruction returns the difference of its two
2434operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2435
2436<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2437'<tt>neg</tt>' instruction present in most other intermediate
2438representations.</p>
2439
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2440<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2441
2442<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
2443 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2444 or <a href="#t_vector">vector</a> values. Both arguments must have identical
2445 types.</p>
2446
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2447<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2448
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2449<p>The value produced is the integer or floating point difference of
2450the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2451
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2452<p>If an integer difference has unsigned overflow, the result returned is the
2453mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2454the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2455
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2456<p>Because LLVM integers use a two's complement representation, this
2457instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2458
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2459<h5>Example:</h5>
2460<pre>
2461 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2462 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2463</pre>
2464</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2465
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2466<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2467<div class="doc_subsubsection">
2468 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2469</div>
2470
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2471<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2472
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2473<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2474<pre> &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2475</pre>
2476<h5>Overview:</h5>
2477<p>The '<tt>mul</tt>' instruction returns the product of its two
2478operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2479
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2480<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2481
2482<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
2483href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2484or <a href="#t_vector">vector</a> values. Both arguments must have identical
2485types.</p>
2486
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2487<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2488
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2489<p>The value produced is the integer or floating point product of the
2490two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2491
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2492<p>If the result of an integer multiplication has unsigned overflow,
2493the result returned is the mathematical result modulo
24942<sup>n</sup>, where n is the bit width of the result.</p>
2495<p>Because LLVM integers use a two's complement representation, and the
2496result is the same width as the operands, this instruction returns the
2497correct result for both signed and unsigned integers. If a full product
2498(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2499should be sign-extended or zero-extended as appropriate to the
2500width of the full product.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2501<h5>Example:</h5>
2502<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
2503</pre>
2504</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2505
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2506<!-- _______________________________________________________________________ -->
2507<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2508</a></div>
2509<div class="doc_text">
2510<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2511<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2512</pre>
2513<h5>Overview:</h5>
2514<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2515operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2516
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2517<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2518
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2519<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2520<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2521values. Both arguments must have identical types.</p>
2522
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2523<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2524
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2525<p>The value produced is the unsigned integer quotient of the two operands.</p>
2526<p>Note that unsigned integer division and signed integer division are distinct
2527operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2528<p>Division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2529<h5>Example:</h5>
2530<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2531</pre>
2532</div>
2533<!-- _______________________________________________________________________ -->
2534<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2535</a> </div>
2536<div class="doc_text">
2537<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2538<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2539 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2540</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2541
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2542<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2543
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2544<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2545operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2546
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2547<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2548
2549<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2550<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2551values. Both arguments must have identical types.</p>
2552
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2553<h5>Semantics:</h5>
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2554<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]2555<p>Note that signed integer division and unsigned integer division are distinct
2556operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2557<p>Division by zero leads to undefined behavior. Overflow also leads to
2558undefined behavior; this is a rare case, but can occur, for example,
2559by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2560<h5>Example:</h5>
2561<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2562</pre>
2563</div>
2564<!-- _______________________________________________________________________ -->
2565<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2566Instruction</a> </div>
2567<div class="doc_text">
2568<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2569<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2570 &lt;result&gt; = fdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2571</pre>
2572<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2573
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2574<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
2575operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2576
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2577<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2578
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2579<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2580<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2581of floating point values. Both arguments must have identical types.</p>
2582
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2583<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2584
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2585<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2586
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2587<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2588
2589<pre>
2590 &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]2591</pre>
2592</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2593
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2594<!-- _______________________________________________________________________ -->
2595<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2596</div>
2597<div class="doc_text">
2598<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2599<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2600</pre>
2601<h5>Overview:</h5>
2602<p>The '<tt>urem</tt>' instruction returns the remainder from the
2603unsigned division of its two arguments.</p>
2604<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2605<p>The two arguments to the '<tt>urem</tt>' instruction must be
2606<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2607values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2608<h5>Semantics:</h5>
2609<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2610This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2611<p>Note that unsigned integer remainder and signed integer remainder are
2612distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2613<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2614<h5>Example:</h5>
2615<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2616</pre>
2617
2618</div>
2619<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2620<div class="doc_subsubsection">
2621 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2622</div>
2623
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2624<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2625
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2626<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2627
2628<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2629 &lt;result&gt; = srem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2630</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2631
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2632<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2633
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2634<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman3e3fd8c2007-11-05 23:35:22 +0000[diff] [blame]2635signed division of its two operands. This instruction can also take
2636<a href="#t_vector">vector</a> versions of the values in which case
2637the elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]2638
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2639<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2640
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2641<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2642<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2643values. Both arguments must have identical types.</p>
2644
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2645<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2646
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2647<p>This instruction returns the <i>remainder</i> of a division (where the result
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2648has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
2649operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2650a value. For more information about the difference, see <a
2651 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2652Math Forum</a>. For a table of how this is implemented in various languages,
2653please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
2654Wikipedia: modulo operation</a>.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2655<p>Note that signed integer remainder and unsigned integer remainder are
2656distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2657<p>Taking the remainder of a division by zero leads to undefined behavior.
2658Overflow also leads to undefined behavior; this is a rare case, but can occur,
2659for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2660(The remainder doesn't actually overflow, but this rule lets srem be
2661implemented using instructions that return both the result of the division
2662and the remainder.)</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2663<h5>Example:</h5>
2664<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2665</pre>
2666
2667</div>
2668<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2669<div class="doc_subsubsection">
2670 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2671
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2672<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2673
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2674<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2675<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2676</pre>
2677<h5>Overview:</h5>
2678<p>The '<tt>frem</tt>' instruction returns the remainder from the
2679division of its two operands.</p>
2680<h5>Arguments:</h5>
2681<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2682<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2683of floating point values. Both arguments must have identical types.</p>
2684
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2685<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2686
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2687<p>This instruction returns the <i>remainder</i> of a division.
2688The remainder has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2689
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2690<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2691
2692<pre>
2693 &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]2694</pre>
2695</div>
2696
2697<!-- ======================================================================= -->
2698<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2699Operations</a> </div>
2700<div class="doc_text">
2701<p>Bitwise binary operators are used to do various forms of
2702bit-twiddling in a program. They are generally very efficient
2703instructions and can commonly be strength reduced from other
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2704instructions. They require two operands of the same type, execute an operation on them,
2705and 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]2706</div>
2707
2708<!-- _______________________________________________________________________ -->
2709<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2710Instruction</a> </div>
2711<div class="doc_text">
2712<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2713<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2714</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2715
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2716<h5>Overview:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2717
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2718<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2719the left a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2720
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2721<h5>Arguments:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2722
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2723<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2724 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2725type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2726
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2727<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2728
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2729<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
2730where n is the width of the result. If <tt>op2</tt> is (statically or dynamically) negative or
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2731equal to or larger than the number of bits in <tt>op1</tt>, the result is undefined.
2732If the arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2733corresponding shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2734
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2735<h5>Example:</h5><pre>
2736 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2737 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2738 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2739 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2740 &lt;result&gt; = shl &lt;2 x i32&gt; &lt; i32 1, i32 1&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 2, i32 4&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2741</pre>
2742</div>
2743<!-- _______________________________________________________________________ -->
2744<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2745Instruction</a> </div>
2746<div class="doc_text">
2747<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2748<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2749</pre>
2750
2751<h5>Overview:</h5>
2752<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2753operand shifted to the right a specified number of bits with zero fill.</p>
2754
2755<h5>Arguments:</h5>
2756<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2757<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2758type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2759
2760<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2761
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2762<p>This instruction always performs a logical shift right operation. The most
2763significant bits of the result will be filled with zero bits after the
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2764shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2765the number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
2766vectors, each vector element of <tt>op1</tt> is shifted by the corresponding shift
2767amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2768
2769<h5>Example:</h5>
2770<pre>
2771 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2772 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2773 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2774 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2775 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2776 &lt;result&gt; = lshr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0x7FFFFFFF, i32 1&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2777</pre>
2778</div>
2779
2780<!-- _______________________________________________________________________ -->
2781<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2782Instruction</a> </div>
2783<div class="doc_text">
2784
2785<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2786<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2787</pre>
2788
2789<h5>Overview:</h5>
2790<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2791operand shifted to the right a specified number of bits with sign extension.</p>
2792
2793<h5>Arguments:</h5>
2794<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2795<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2796type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2797
2798<h5>Semantics:</h5>
2799<p>This instruction always performs an arithmetic shift right operation,
2800The most significant bits of the result will be filled with the sign bit
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2801of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2802larger than the number of bits in <tt>op1</tt>, the result is undefined. If the
2803arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2804corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2805
2806<h5>Example:</h5>
2807<pre>
2808 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2809 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2810 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2811 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2812 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2813 &lt;result&gt; = ashr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 3&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 -1, i32 0&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2814</pre>
2815</div>
2816
2817<!-- _______________________________________________________________________ -->
2818<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2819Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2820
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2821<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2822
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2823<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2824
2825<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2826 &lt;result&gt; = and &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2827</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2828
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2829<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2830
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2831<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2832its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2833
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2834<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2835
2836<p>The two arguments to the '<tt>and</tt>' instruction must be
2837<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2838values. Both arguments must have identical types.</p>
2839
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2840<h5>Semantics:</h5>
2841<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
2842<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2843<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2844<table border="1" cellspacing="0" cellpadding="4">
2845 <tbody>
2846 <tr>
2847 <td>In0</td>
2848 <td>In1</td>
2849 <td>Out</td>
2850 </tr>
2851 <tr>
2852 <td>0</td>
2853 <td>0</td>
2854 <td>0</td>
2855 </tr>
2856 <tr>
2857 <td>0</td>
2858 <td>1</td>
2859 <td>0</td>
2860 </tr>
2861 <tr>
2862 <td>1</td>
2863 <td>0</td>
2864 <td>0</td>
2865 </tr>
2866 <tr>
2867 <td>1</td>
2868 <td>1</td>
2869 <td>1</td>
2870 </tr>
2871 </tbody>
2872</table>
2873</div>
2874<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2875<pre>
2876 &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]2877 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2878 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
2879</pre>
2880</div>
2881<!-- _______________________________________________________________________ -->
2882<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
2883<div class="doc_text">
2884<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2885<pre> &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2886</pre>
2887<h5>Overview:</h5>
2888<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2889or of its two operands.</p>
2890<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2891
2892<p>The two arguments to the '<tt>or</tt>' instruction must be
2893<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2894values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2895<h5>Semantics:</h5>
2896<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
2897<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2898<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2899<table border="1" cellspacing="0" cellpadding="4">
2900 <tbody>
2901 <tr>
2902 <td>In0</td>
2903 <td>In1</td>
2904 <td>Out</td>
2905 </tr>
2906 <tr>
2907 <td>0</td>
2908 <td>0</td>
2909 <td>0</td>
2910 </tr>
2911 <tr>
2912 <td>0</td>
2913 <td>1</td>
2914 <td>1</td>
2915 </tr>
2916 <tr>
2917 <td>1</td>
2918 <td>0</td>
2919 <td>1</td>
2920 </tr>
2921 <tr>
2922 <td>1</td>
2923 <td>1</td>
2924 <td>1</td>
2925 </tr>
2926 </tbody>
2927</table>
2928</div>
2929<h5>Example:</h5>
2930<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2931 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2932 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
2933</pre>
2934</div>
2935<!-- _______________________________________________________________________ -->
2936<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2937Instruction</a> </div>
2938<div class="doc_text">
2939<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2940<pre> &lt;result&gt; = xor &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2941</pre>
2942<h5>Overview:</h5>
2943<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2944or of its two operands. The <tt>xor</tt> is used to implement the
2945"one's complement" operation, which is the "~" operator in C.</p>
2946<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2947<p>The two arguments to the '<tt>xor</tt>' instruction must be
2948<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2949values. Both arguments must have identical types.</p>
2950
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2951<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2952
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2953<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
2954<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2955<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2956<table border="1" cellspacing="0" cellpadding="4">
2957 <tbody>
2958 <tr>
2959 <td>In0</td>
2960 <td>In1</td>
2961 <td>Out</td>
2962 </tr>
2963 <tr>
2964 <td>0</td>
2965 <td>0</td>
2966 <td>0</td>
2967 </tr>
2968 <tr>
2969 <td>0</td>
2970 <td>1</td>
2971 <td>1</td>
2972 </tr>
2973 <tr>
2974 <td>1</td>
2975 <td>0</td>
2976 <td>1</td>
2977 </tr>
2978 <tr>
2979 <td>1</td>
2980 <td>1</td>
2981 <td>0</td>
2982 </tr>
2983 </tbody>
2984</table>
2985</div>
2986<p> </p>
2987<h5>Example:</h5>
2988<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2989 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2990 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2991 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
2992</pre>
2993</div>
2994
2995<!-- ======================================================================= -->
2996<div class="doc_subsection">
2997 <a name="vectorops">Vector Operations</a>
2998</div>
2999
3000<div class="doc_text">
3001
3002<p>LLVM supports several instructions to represent vector operations in a
3003target-independent manner. These instructions cover the element-access and
3004vector-specific operations needed to process vectors effectively. While LLVM
3005does directly support these vector operations, many sophisticated algorithms
3006will want to use target-specific intrinsics to take full advantage of a specific
3007target.</p>
3008
3009</div>
3010
3011<!-- _______________________________________________________________________ -->
3012<div class="doc_subsubsection">
3013 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3014</div>
3015
3016<div class="doc_text">
3017
3018<h5>Syntax:</h5>
3019
3020<pre>
3021 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3022</pre>
3023
3024<h5>Overview:</h5>
3025
3026<p>
3027The '<tt>extractelement</tt>' instruction extracts a single scalar
3028element from a vector at a specified index.
3029</p>
3030
3031
3032<h5>Arguments:</h5>
3033
3034<p>
3035The first operand of an '<tt>extractelement</tt>' instruction is a
3036value of <a href="#t_vector">vector</a> type. The second operand is
3037an index indicating the position from which to extract the element.
3038The index may be a variable.</p>
3039
3040<h5>Semantics:</h5>
3041
3042<p>
3043The result is a scalar of the same type as the element type of
3044<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3045<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3046results are undefined.
3047</p>
3048
3049<h5>Example:</h5>
3050
3051<pre>
3052 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
3053</pre>
3054</div>
3055
3056
3057<!-- _______________________________________________________________________ -->
3058<div class="doc_subsubsection">
3059 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3060</div>
3061
3062<div class="doc_text">
3063
3064<h5>Syntax:</h5>
3065
3066<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3067 &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]3068</pre>
3069
3070<h5>Overview:</h5>
3071
3072<p>
3073The '<tt>insertelement</tt>' instruction inserts a scalar
3074element into a vector at a specified index.
3075</p>
3076
3077
3078<h5>Arguments:</h5>
3079
3080<p>
3081The first operand of an '<tt>insertelement</tt>' instruction is a
3082value of <a href="#t_vector">vector</a> type. The second operand is a
3083scalar value whose type must equal the element type of the first
3084operand. The third operand is an index indicating the position at
3085which to insert the value. The index may be a variable.</p>
3086
3087<h5>Semantics:</h5>
3088
3089<p>
3090The result is a vector of the same type as <tt>val</tt>. Its
3091element values are those of <tt>val</tt> except at position
3092<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
3093exceeds the length of <tt>val</tt>, the results are undefined.
3094</p>
3095
3096<h5>Example:</h5>
3097
3098<pre>
3099 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
3100</pre>
3101</div>
3102
3103<!-- _______________________________________________________________________ -->
3104<div class="doc_subsubsection">
3105 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3106</div>
3107
3108<div class="doc_text">
3109
3110<h5>Syntax:</h5>
3111
3112<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3113 &lt;result&gt; = shufflevector &lt;n x &lt;ty&gt;&gt; &lt;v1&gt;, &lt;n x &lt;ty&gt;&gt; &lt;v2&gt;, &lt;m x i32&gt; &lt;mask&gt; <i>; yields &lt;m x &lt;ty&gt;&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3114</pre>
3115
3116<h5>Overview:</h5>
3117
3118<p>
3119The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3120from two input vectors, returning a vector with the same element type as
3121the input and length that is the same as the shuffle mask.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3122</p>
3123
3124<h5>Arguments:</h5>
3125
3126<p>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3127The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3128with types that match each other. The third argument is a shuffle mask whose
3129element type is always 'i32'. The result of the instruction is a vector whose
3130length is the same as the shuffle mask and whose element type is the same as
3131the element type of the first two operands.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3132</p>
3133
3134<p>
3135The shuffle mask operand is required to be a constant vector with either
3136constant integer or undef values.
3137</p>
3138
3139<h5>Semantics:</h5>
3140
3141<p>
3142The elements of the two input vectors are numbered from left to right across
3143both of the vectors. The shuffle mask operand specifies, for each element of
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3144the result vector, which element of the two input vectors the result element
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3145gets. The element selector may be undef (meaning "don't care") and the second
3146operand may be undef if performing a shuffle from only one vector.
3147</p>
3148
3149<h5>Example:</h5>
3150
3151<pre>
3152 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3153 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3154 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3155 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i> - Identity shuffle.
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3156 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3157 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3158 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3159 &lt;8 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7 &gt; <i>; yields &lt;8 x i32&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3160</pre>
3161</div>
3162
3163
3164<!-- ======================================================================= -->
3165<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3166 <a name="aggregateops">Aggregate Operations</a>
3167</div>
3168
3169<div class="doc_text">
3170
3171<p>LLVM supports several instructions for working with aggregate values.
3172</p>
3173
3174</div>
3175
3176<!-- _______________________________________________________________________ -->
3177<div class="doc_subsubsection">
3178 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3179</div>
3180
3181<div class="doc_text">
3182
3183<h5>Syntax:</h5>
3184
3185<pre>
3186 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3187</pre>
3188
3189<h5>Overview:</h5>
3190
3191<p>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3192The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3193or array element from an aggregate value.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3194</p>
3195
3196
3197<h5>Arguments:</h5>
3198
3199<p>
3200The first operand of an '<tt>extractvalue</tt>' instruction is a
3201value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3202type. The operands are constant indices to specify which value to extract
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3203in a similar manner as indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3204'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3205</p>
3206
3207<h5>Semantics:</h5>
3208
3209<p>
3210The result is the value at the position in the aggregate specified by
3211the index operands.
3212</p>
3213
3214<h5>Example:</h5>
3215
3216<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3217 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3218</pre>
3219</div>
3220
3221
3222<!-- _______________________________________________________________________ -->
3223<div class="doc_subsubsection">
3224 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3225</div>
3226
3227<div class="doc_text">
3228
3229<h5>Syntax:</h5>
3230
3231<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3232 &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]3233</pre>
3234
3235<h5>Overview:</h5>
3236
3237<p>
3238The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3239into a struct field or array element in an aggregate.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3240</p>
3241
3242
3243<h5>Arguments:</h5>
3244
3245<p>
3246The first operand of an '<tt>insertvalue</tt>' instruction is a
3247value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
3248The second operand is a first-class value to insert.
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]3249The following operands are constant indices
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3250indicating the position at which to insert the value in a similar manner as
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3251indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3252'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3253The value to insert must have the same type as the value identified
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3254by the indices.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3255</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3256
3257<h5>Semantics:</h5>
3258
3259<p>
3260The result is an aggregate of the same type as <tt>val</tt>. Its
3261value is that of <tt>val</tt> except that the value at the position
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3262specified by the indices is that of <tt>elt</tt>.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3263</p>
3264
3265<h5>Example:</h5>
3266
3267<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3268 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3269</pre>
3270</div>
3271
3272
3273<!-- ======================================================================= -->
3274<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3275 <a name="memoryops">Memory Access and Addressing Operations</a>
3276</div>
3277
3278<div class="doc_text">
3279
3280<p>A key design point of an SSA-based representation is how it
3281represents memory. In LLVM, no memory locations are in SSA form, which
3282makes things very simple. This section describes how to read, write,
3283allocate, and free memory in LLVM.</p>
3284
3285</div>
3286
3287<!-- _______________________________________________________________________ -->
3288<div class="doc_subsubsection">
3289 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3290</div>
3291
3292<div class="doc_text">
3293
3294<h5>Syntax:</h5>
3295
3296<pre>
3297 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3298</pre>
3299
3300<h5>Overview:</h5>
3301
3302<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3303heap and returns a pointer to it. The object is always allocated in the generic
3304address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3305
3306<h5>Arguments:</h5>
3307
3308<p>The '<tt>malloc</tt>' instruction allocates
3309<tt>sizeof(&lt;type&gt;)*NumElements</tt>
3310bytes of memory from the operating system and returns a pointer of the
3311appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3312number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3313If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3314be aligned to at least that boundary. If not specified, or if zero, the target can
3315choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3316
3317<p>'<tt>type</tt>' must be a sized type.</p>
3318
3319<h5>Semantics:</h5>
3320
3321<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]3322a pointer is returned. The result of a zero byte allocation is undefined. The
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3323result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3324
3325<h5>Example:</h5>
3326
3327<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3328 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3329
3330 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3331 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3332 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3333 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3334 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3335</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3336
3337<p>Note that the code generator does not yet respect the
3338 alignment value.</p>
3339
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3340</div>
3341
3342<!-- _______________________________________________________________________ -->
3343<div class="doc_subsubsection">
3344 <a name="i_free">'<tt>free</tt>' Instruction</a>
3345</div>
3346
3347<div class="doc_text">
3348
3349<h5>Syntax:</h5>
3350
3351<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3352 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3353</pre>
3354
3355<h5>Overview:</h5>
3356
3357<p>The '<tt>free</tt>' instruction returns memory back to the unused
3358memory heap to be reallocated in the future.</p>
3359
3360<h5>Arguments:</h5>
3361
3362<p>'<tt>value</tt>' shall be a pointer value that points to a value
3363that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3364instruction.</p>
3365
3366<h5>Semantics:</h5>
3367
3368<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner329d6532008-04-19 22:41:32 +0000[diff] [blame]3369after this instruction executes. If the pointer is null, the operation
3370is a noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3371
3372<h5>Example:</h5>
3373
3374<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3375 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3376 free [4 x i8]* %array
3377</pre>
3378</div>
3379
3380<!-- _______________________________________________________________________ -->
3381<div class="doc_subsubsection">
3382 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3383</div>
3384
3385<div class="doc_text">
3386
3387<h5>Syntax:</h5>
3388
3389<pre>
3390 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3391</pre>
3392
3393<h5>Overview:</h5>
3394
3395<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3396currently executing function, to be automatically released when this function
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3397returns to its caller. The object is always allocated in the generic address
3398space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3399
3400<h5>Arguments:</h5>
3401
3402<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
3403bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3404appropriate type to the program. If "NumElements" is specified, it is the
3405number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3406If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3407to be aligned to at least that boundary. If not specified, or if zero, the target
3408can choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3409
3410<p>'<tt>type</tt>' may be any sized type.</p>
3411
3412<h5>Semantics:</h5>
3413
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3414<p>Memory is allocated; a pointer is returned. The operation is undefiend if
3415there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3416memory is automatically released when the function returns. The '<tt>alloca</tt>'
3417instruction is commonly used to represent automatic variables that must
3418have an address available. When the function returns (either with the <tt><a
3419 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]3420instructions), the memory is reclaimed. Allocating zero bytes
3421is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3422
3423<h5>Example:</h5>
3424
3425<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3426 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3427 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3428 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3429 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3430</pre>
3431</div>
3432
3433<!-- _______________________________________________________________________ -->
3434<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3435Instruction</a> </div>
3436<div class="doc_text">
3437<h5>Syntax:</h5>
3438<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>
3439<h5>Overview:</h5>
3440<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
3441<h5>Arguments:</h5>
3442<p>The argument to the '<tt>load</tt>' instruction specifies the memory
3443address from which to load. The pointer must point to a <a
3444 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3445marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
3446the number or order of execution of this <tt>load</tt> with other
3447volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3448instructions. </p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3449<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3450The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3451(that is, the alignment of the memory address). A value of 0 or an
3452omitted "align" argument means that the operation has the preferential
3453alignment for the target. It is the responsibility of the code emitter
3454to ensure that the alignment information is correct. Overestimating
3455the alignment results in an undefined behavior. Underestimating the
3456alignment may produce less efficient code. An alignment of 1 is always
3457safe.
3458</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3459<h5>Semantics:</h5>
3460<p>The location of memory pointed to is loaded.</p>
3461<h5>Examples:</h5>
3462<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3463 <a
3464 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3465 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3466</pre>
3467</div>
3468<!-- _______________________________________________________________________ -->
3469<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3470Instruction</a> </div>
3471<div class="doc_text">
3472<h5>Syntax:</h5>
3473<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3474 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3475</pre>
3476<h5>Overview:</h5>
3477<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
3478<h5>Arguments:</h5>
3479<p>There are two arguments to the '<tt>store</tt>' instruction: a value
3480to 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]3481operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3482of the '<tt>&lt;value&gt;</tt>'
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3483operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
3484optimizer is not allowed to modify the number or order of execution of
3485this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3486 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3487<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3488The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3489(that is, the alignment of the memory address). A value of 0 or an
3490omitted "align" argument means that the operation has the preferential
3491alignment for the target. It is the responsibility of the code emitter
3492to ensure that the alignment information is correct. Overestimating
3493the alignment results in an undefined behavior. Underestimating the
3494alignment may produce less efficient code. An alignment of 1 is always
3495safe.
3496</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3497<h5>Semantics:</h5>
3498<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
3499at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
3500<h5>Example:</h5>
3501<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3502 store i32 3, i32* %ptr <i>; yields {void}</i>
3503 %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]3504</pre>
3505</div>
3506
3507<!-- _______________________________________________________________________ -->
3508<div class="doc_subsubsection">
3509 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3510</div>
3511
3512<div class="doc_text">
3513<h5>Syntax:</h5>
3514<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3515 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3516</pre>
3517
3518<h5>Overview:</h5>
3519
3520<p>
3521The '<tt>getelementptr</tt>' instruction is used to get the address of a
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3522subelement of an aggregate data structure. It performs address calculation only
3523and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3524
3525<h5>Arguments:</h5>
3526
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3527<p>The first argument is always a pointer, and forms the basis of the
3528calculation. The remaining arguments are indices, that indicate which of the
3529elements of the aggregate object are indexed. The interpretation of each index
3530is dependent on the type being indexed into. The first index always indexes the
3531pointer value given as the first argument, the second index indexes a value of
3532the type pointed to (not necessarily the value directly pointed to, since the
3533first index can be non-zero), etc. The first type indexed into must be a pointer
3534value, subsequent types can be arrays, vectors and structs. Note that subsequent
3535types being indexed into can never be pointers, since that would require loading
3536the pointer before continuing calculation.</p>
3537
3538<p>The type of each index argument depends on the type it is indexing into.
3539When indexing into a (packed) structure, only <tt>i32</tt> integer
3540<b>constants</b> are allowed. When indexing into an array, pointer or vector,
3541only integers of 32 or 64 bits are allowed (also non-constants). 32-bit values
3542will be sign extended to 64-bits if required.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3543
3544<p>For example, let's consider a C code fragment and how it gets
3545compiled to LLVM:</p>
3546
3547<div class="doc_code">
3548<pre>
3549struct RT {
3550 char A;
3551 int B[10][20];
3552 char C;
3553};
3554struct ST {
3555 int X;
3556 double Y;
3557 struct RT Z;
3558};
3559
3560int *foo(struct ST *s) {
3561 return &amp;s[1].Z.B[5][13];
3562}
3563</pre>
3564</div>
3565
3566<p>The LLVM code generated by the GCC frontend is:</p>
3567
3568<div class="doc_code">
3569<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]3570%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
3571%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3572
3573define i32* %foo(%ST* %s) {
3574entry:
3575 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3576 ret i32* %reg
3577}
3578</pre>
3579</div>
3580
3581<h5>Semantics:</h5>
3582
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3583<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
3584type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3585}</tt>' type, a structure. The second index indexes into the third element of
3586the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3587i8 }</tt>' type, another structure. The third index indexes into the second
3588element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3589array. The two dimensions of the array are subscripted into, yielding an
3590'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3591to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
3592
3593<p>Note that it is perfectly legal to index partially through a
3594structure, returning a pointer to an inner element. Because of this,
3595the LLVM code for the given testcase is equivalent to:</p>
3596
3597<pre>
3598 define i32* %foo(%ST* %s) {
3599 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3600 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3601 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3602 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3603 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3604 ret i32* %t5
3605 }
3606</pre>
3607
3608<p>Note that it is undefined to access an array out of bounds: array and
3609pointer indexes must always be within the defined bounds of the array type.
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]3610The one exception for this rule is zero length arrays. These arrays are
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3611defined to be accessible as variable length arrays, which requires access
3612beyond the zero'th element.</p>
3613
3614<p>The getelementptr instruction is often confusing. For some more insight
3615into how it works, see <a href="GetElementPtr.html">the getelementptr
3616FAQ</a>.</p>
3617
3618<h5>Example:</h5>
3619
3620<pre>
3621 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3622 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3623 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3624 %vptr = getelementptr {i32, &lt;2 x i8&gt;}* %svptr, i64 0, i32 1, i32 1
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3625 <i>; yields i8*:eptr</i>
3626 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3627</pre>
3628</div>
3629
3630<!-- ======================================================================= -->
3631<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3632</div>
3633<div class="doc_text">
3634<p>The instructions in this category are the conversion instructions (casting)
3635which all take a single operand and a type. They perform various bit conversions
3636on the operand.</p>
3637</div>
3638
3639<!-- _______________________________________________________________________ -->
3640<div class="doc_subsubsection">
3641 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3642</div>
3643<div class="doc_text">
3644
3645<h5>Syntax:</h5>
3646<pre>
3647 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3648</pre>
3649
3650<h5>Overview:</h5>
3651<p>
3652The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3653</p>
3654
3655<h5>Arguments:</h5>
3656<p>
3657The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3658be an <a href="#t_integer">integer</a> type, and a type that specifies the size
3659and type of the result, which must be an <a href="#t_integer">integer</a>
3660type. The bit size of <tt>value</tt> must be larger than the bit size of
3661<tt>ty2</tt>. Equal sized types are not allowed.</p>
3662
3663<h5>Semantics:</h5>
3664<p>
3665The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
3666and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3667larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3668It will always truncate bits.</p>
3669
3670<h5>Example:</h5>
3671<pre>
3672 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3673 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3674 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
3675</pre>
3676</div>
3677
3678<!-- _______________________________________________________________________ -->
3679<div class="doc_subsubsection">
3680 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3681</div>
3682<div class="doc_text">
3683
3684<h5>Syntax:</h5>
3685<pre>
3686 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3687</pre>
3688
3689<h5>Overview:</h5>
3690<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3691<tt>ty2</tt>.</p>
3692
3693
3694<h5>Arguments:</h5>
3695<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
3696<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3697also be of <a href="#t_integer">integer</a> type. The bit size of the
3698<tt>value</tt> must be smaller than the bit size of the destination type,
3699<tt>ty2</tt>.</p>
3700
3701<h5>Semantics:</h5>
3702<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
3703bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
3704
3705<p>When zero extending from i1, the result will always be either 0 or 1.</p>
3706
3707<h5>Example:</h5>
3708<pre>
3709 %X = zext i32 257 to i64 <i>; yields i64:257</i>
3710 %Y = zext i1 true to i32 <i>; yields i32:1</i>
3711</pre>
3712</div>
3713
3714<!-- _______________________________________________________________________ -->
3715<div class="doc_subsubsection">
3716 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3717</div>
3718<div class="doc_text">
3719
3720<h5>Syntax:</h5>
3721<pre>
3722 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3723</pre>
3724
3725<h5>Overview:</h5>
3726<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3727
3728<h5>Arguments:</h5>
3729<p>
3730The '<tt>sext</tt>' instruction takes a value to cast, which must be of
3731<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3732also be of <a href="#t_integer">integer</a> type. The bit size of the
3733<tt>value</tt> must be smaller than the bit size of the destination type,
3734<tt>ty2</tt>.</p>
3735
3736<h5>Semantics:</h5>
3737<p>
3738The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3739bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
3740the type <tt>ty2</tt>.</p>
3741
3742<p>When sign extending from i1, the extension always results in -1 or 0.</p>
3743
3744<h5>Example:</h5>
3745<pre>
3746 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
3747 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
3748</pre>
3749</div>
3750
3751<!-- _______________________________________________________________________ -->
3752<div class="doc_subsubsection">
3753 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3754</div>
3755
3756<div class="doc_text">
3757
3758<h5>Syntax:</h5>
3759
3760<pre>
3761 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3762</pre>
3763
3764<h5>Overview:</h5>
3765<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3766<tt>ty2</tt>.</p>
3767
3768
3769<h5>Arguments:</h5>
3770<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3771 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3772cast it to. The size of <tt>value</tt> must be larger than the size of
3773<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3774<i>no-op cast</i>.</p>
3775
3776<h5>Semantics:</h5>
3777<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3778<a href="#t_floating">floating point</a> type to a smaller
3779<a href="#t_floating">floating point</a> type. If the value cannot fit within
3780the destination type, <tt>ty2</tt>, then the results are undefined.</p>
3781
3782<h5>Example:</h5>
3783<pre>
3784 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3785 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3786</pre>
3787</div>
3788
3789<!-- _______________________________________________________________________ -->
3790<div class="doc_subsubsection">
3791 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3792</div>
3793<div class="doc_text">
3794
3795<h5>Syntax:</h5>
3796<pre>
3797 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3798</pre>
3799
3800<h5>Overview:</h5>
3801<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3802floating point value.</p>
3803
3804<h5>Arguments:</h5>
3805<p>The '<tt>fpext</tt>' instruction takes a
3806<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
3807and a <a href="#t_floating">floating point</a> type to cast it to. The source
3808type must be smaller than the destination type.</p>
3809
3810<h5>Semantics:</h5>
3811<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
3812<a href="#t_floating">floating point</a> type to a larger
3813<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
3814used to make a <i>no-op cast</i> because it always changes bits. Use
3815<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
3816
3817<h5>Example:</h5>
3818<pre>
3819 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3820 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3821</pre>
3822</div>
3823
3824<!-- _______________________________________________________________________ -->
3825<div class="doc_subsubsection">
3826 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
3827</div>
3828<div class="doc_text">
3829
3830<h5>Syntax:</h5>
3831<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3832 &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]3833</pre>
3834
3835<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3836<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3837unsigned integer equivalent of type <tt>ty2</tt>.
3838</p>
3839
3840<h5>Arguments:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3841<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]3842scalar or vector <a href="#t_floating">floating point</a> value, and a type
3843to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3844type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3845vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3846
3847<h5>Semantics:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3848<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3849<a href="#t_floating">floating point</a> operand into the nearest (rounding
3850towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3851the results are undefined.</p>
3852
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3853<h5>Example:</h5>
3854<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3855 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3856 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3857 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3858</pre>
3859</div>
3860
3861<!-- _______________________________________________________________________ -->
3862<div class="doc_subsubsection">
3863 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
3864</div>
3865<div class="doc_text">
3866
3867<h5>Syntax:</h5>
3868<pre>
3869 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3870</pre>
3871
3872<h5>Overview:</h5>
3873<p>The '<tt>fptosi</tt>' instruction converts
3874<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
3875</p>
3876
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3877<h5>Arguments:</h5>
3878<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]3879scalar or vector <a href="#t_floating">floating point</a> value, and a type
3880to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3881type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3882vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3883
3884<h5>Semantics:</h5>
3885<p>The '<tt>fptosi</tt>' instruction converts its
3886<a href="#t_floating">floating point</a> operand into the nearest (rounding
3887towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3888the results are undefined.</p>
3889
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3890<h5>Example:</h5>
3891<pre>
3892 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3893 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3894 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
3895</pre>
3896</div>
3897
3898<!-- _______________________________________________________________________ -->
3899<div class="doc_subsubsection">
3900 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
3901</div>
3902<div class="doc_text">
3903
3904<h5>Syntax:</h5>
3905<pre>
3906 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3907</pre>
3908
3909<h5>Overview:</h5>
3910<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
3911integer and converts that value to the <tt>ty2</tt> type.</p>
3912
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3913<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3914<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3915scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3916to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3917type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3918floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3919
3920<h5>Semantics:</h5>
3921<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
3922integer quantity and converts it to the corresponding floating point value. If
3923the value cannot fit in the floating point value, the results are undefined.</p>
3924
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3925<h5>Example:</h5>
3926<pre>
3927 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3928 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3929</pre>
3930</div>
3931
3932<!-- _______________________________________________________________________ -->
3933<div class="doc_subsubsection">
3934 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
3935</div>
3936<div class="doc_text">
3937
3938<h5>Syntax:</h5>
3939<pre>
3940 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3941</pre>
3942
3943<h5>Overview:</h5>
3944<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
3945integer and converts that value to the <tt>ty2</tt> type.</p>
3946
3947<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3948<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3949scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3950to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3951type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3952floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3953
3954<h5>Semantics:</h5>
3955<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
3956integer quantity and converts it to the corresponding floating point value. If
3957the value cannot fit in the floating point value, the results are undefined.</p>
3958
3959<h5>Example:</h5>
3960<pre>
3961 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3962 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3963</pre>
3964</div>
3965
3966<!-- _______________________________________________________________________ -->
3967<div class="doc_subsubsection">
3968 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3969</div>
3970<div class="doc_text">
3971
3972<h5>Syntax:</h5>
3973<pre>
3974 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3975</pre>
3976
3977<h5>Overview:</h5>
3978<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3979the integer type <tt>ty2</tt>.</p>
3980
3981<h5>Arguments:</h5>
3982<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3983must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3984<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3985
3986<h5>Semantics:</h5>
3987<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3988<tt>ty2</tt> by interpreting the pointer value as an integer and either
3989truncating or zero extending that value to the size of the integer type. If
3990<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3991<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3992are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3993change.</p>
3994
3995<h5>Example:</h5>
3996<pre>
3997 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3998 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
3999</pre>
4000</div>
4001
4002<!-- _______________________________________________________________________ -->
4003<div class="doc_subsubsection">
4004 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4005</div>
4006<div class="doc_text">
4007
4008<h5>Syntax:</h5>
4009<pre>
4010 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4011</pre>
4012
4013<h5>Overview:</h5>
4014<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
4015a pointer type, <tt>ty2</tt>.</p>
4016
4017<h5>Arguments:</h5>
4018<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
4019value to cast, and a type to cast it to, which must be a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4020<a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4021
4022<h5>Semantics:</h5>
4023<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
4024<tt>ty2</tt> by applying either a zero extension or a truncation depending on
4025the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4026size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
4027the size of a pointer then a zero extension is done. If they are the same size,
4028nothing is done (<i>no-op cast</i>).</p>
4029
4030<h5>Example:</h5>
4031<pre>
4032 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4033 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4034 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
4035</pre>
4036</div>
4037
4038<!-- _______________________________________________________________________ -->
4039<div class="doc_subsubsection">
4040 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4041</div>
4042<div class="doc_text">
4043
4044<h5>Syntax:</h5>
4045<pre>
4046 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4047</pre>
4048
4049<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4050
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4051<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4052<tt>ty2</tt> without changing any bits.</p>
4053
4054<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4055
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4056<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Dan Gohman7305fa02008-09-08 16:45:59 +0000[diff] [blame]4057a non-aggregate first class value, and a type to cast it to, which must also be
4058a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
4059<tt>value</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4060and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4061type is a pointer, the destination type must also be a pointer. This
4062instruction supports bitwise conversion of vectors to integers and to vectors
4063of other types (as long as they have the same size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4064
4065<h5>Semantics:</h5>
4066<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4067<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4068this conversion. The conversion is done as if the <tt>value</tt> had been
4069stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
4070converted to other pointer types with this instruction. To convert pointers to
4071other types, use the <a href="#i_inttoptr">inttoptr</a> or
4072<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
4073
4074<h5>Example:</h5>
4075<pre>
4076 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4077 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4078 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4079</pre>
4080</div>
4081
4082<!-- ======================================================================= -->
4083<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
4084<div class="doc_text">
4085<p>The instructions in this category are the "miscellaneous"
4086instructions, which defy better classification.</p>
4087</div>
4088
4089<!-- _______________________________________________________________________ -->
4090<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4091</div>
4092<div class="doc_text">
4093<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4094<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4095</pre>
4096<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4097<p>The '<tt>icmp</tt>' instruction returns a boolean value or
4098a vector of boolean values based on comparison
4099of its two integer, integer vector, or pointer operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4100<h5>Arguments:</h5>
4101<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
4102the condition code indicating the kind of comparison to perform. It is not
4103a value, just a keyword. The possible condition code are:
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4104</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4105<ol>
4106 <li><tt>eq</tt>: equal</li>
4107 <li><tt>ne</tt>: not equal </li>
4108 <li><tt>ugt</tt>: unsigned greater than</li>
4109 <li><tt>uge</tt>: unsigned greater or equal</li>
4110 <li><tt>ult</tt>: unsigned less than</li>
4111 <li><tt>ule</tt>: unsigned less or equal</li>
4112 <li><tt>sgt</tt>: signed greater than</li>
4113 <li><tt>sge</tt>: signed greater or equal</li>
4114 <li><tt>slt</tt>: signed less than</li>
4115 <li><tt>sle</tt>: signed less or equal</li>
4116</ol>
4117<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4118<a href="#t_pointer">pointer</a>
4119or integer <a href="#t_vector">vector</a> typed.
4120They must also be identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4121<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4122<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4123the condition code given as <tt>cond</tt>. The comparison performed always
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4124yields either an <a href="#t_primitive"><tt>i1</tt></a> or vector of <tt>i1</tt> result, as follows:
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4125</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4126<ol>
4127 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
4128 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
4129 </li>
4130 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4131 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4132 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4133 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4134 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4135 <tt>true</tt> if <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4136 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4137 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4138 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4139 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4140 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4141 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4142 <li><tt>sge</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4143 <tt>true</tt> if <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4144 <li><tt>slt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4145 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4146 <li><tt>sle</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4147 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4148</ol>
4149<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
4150values are compared as if they were integers.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4151<p>If the operands are integer vectors, then they are compared
4152element by element. The result is an <tt>i1</tt> vector with
4153the same number of elements as the values being compared.
4154Otherwise, the result is an <tt>i1</tt>.
4155</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4156
4157<h5>Example:</h5>
4158<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
4159 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4160 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4161 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4162 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4163 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4164</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4165
4166<p>Note that the code generator does not yet support vector types with
4167 the <tt>icmp</tt> instruction.</p>
4168
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4169</div>
4170
4171<!-- _______________________________________________________________________ -->
4172<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4173</div>
4174<div class="doc_text">
4175<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4176<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4177</pre>
4178<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4179<p>The '<tt>fcmp</tt>' instruction returns a boolean value
4180or vector of boolean values based on comparison
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4181of its operands.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4182<p>
4183If the operands are floating point scalars, then the result
4184type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
4185</p>
4186<p>If the operands are floating point vectors, then the result type
4187is a vector of boolean with the same number of elements as the
4188operands being compared.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4189<h5>Arguments:</h5>
4190<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
4191the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4192a value, just a keyword. The possible condition code are:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4193<ol>
4194 <li><tt>false</tt>: no comparison, always returns false</li>
4195 <li><tt>oeq</tt>: ordered and equal</li>
4196 <li><tt>ogt</tt>: ordered and greater than </li>
4197 <li><tt>oge</tt>: ordered and greater than or equal</li>
4198 <li><tt>olt</tt>: ordered and less than </li>
4199 <li><tt>ole</tt>: ordered and less than or equal</li>
4200 <li><tt>one</tt>: ordered and not equal</li>
4201 <li><tt>ord</tt>: ordered (no nans)</li>
4202 <li><tt>ueq</tt>: unordered or equal</li>
4203 <li><tt>ugt</tt>: unordered or greater than </li>
4204 <li><tt>uge</tt>: unordered or greater than or equal</li>
4205 <li><tt>ult</tt>: unordered or less than </li>
4206 <li><tt>ule</tt>: unordered or less than or equal</li>
4207 <li><tt>une</tt>: unordered or not equal</li>
4208 <li><tt>uno</tt>: unordered (either nans)</li>
4209 <li><tt>true</tt>: no comparison, always returns true</li>
4210</ol>
4211<p><i>Ordered</i> means that neither operand is a QNAN while
4212<i>unordered</i> means that either operand may be a QNAN.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4213<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
4214either a <a href="#t_floating">floating point</a> type
4215or a <a href="#t_vector">vector</a> of floating point type.
4216They must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4217<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4218<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4219according to the condition code given as <tt>cond</tt>.
4220If the operands are vectors, then the vectors are compared
4221element by element.
4222Each comparison performed
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4223always yields an <a href="#t_primitive">i1</a> result, as follows:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4224<ol>
4225 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
4226 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4227 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4228 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4229 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4230 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4231 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4232 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4233 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4234 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4235 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4236 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4237 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4238 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
4239 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4240 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4241 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4242 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4243 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4244 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4245 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4246 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4247 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4248 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4249 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4250 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4251 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
4252 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4253</ol>
4254
4255<h5>Example:</h5>
4256<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4257 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4258 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4259 &lt;result&gt; = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4260</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4261
4262<p>Note that the code generator does not yet support vector types with
4263 the <tt>fcmp</tt> instruction.</p>
4264
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4265</div>
4266
4267<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4268<div class="doc_subsubsection">
4269 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
4270</div>
4271<div class="doc_text">
4272<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4273<pre> &lt;result&gt; = vicmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4274</pre>
4275<h5>Overview:</h5>
4276<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
4277element-wise comparison of its two integer vector operands.</p>
4278<h5>Arguments:</h5>
4279<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
4280the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4281a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4282<ol>
4283 <li><tt>eq</tt>: equal</li>
4284 <li><tt>ne</tt>: not equal </li>
4285 <li><tt>ugt</tt>: unsigned greater than</li>
4286 <li><tt>uge</tt>: unsigned greater or equal</li>
4287 <li><tt>ult</tt>: unsigned less than</li>
4288 <li><tt>ule</tt>: unsigned less or equal</li>
4289 <li><tt>sgt</tt>: signed greater than</li>
4290 <li><tt>sge</tt>: signed greater or equal</li>
4291 <li><tt>slt</tt>: signed less than</li>
4292 <li><tt>sle</tt>: signed less or equal</li>
4293</ol>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4294<p>The remaining two arguments must be <a href="#t_vector">vector</a> or
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4295<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
4296<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4297<p>The '<tt>vicmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4298according to the condition code given as <tt>cond</tt>. The comparison yields a
4299<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
4300identical type as the values being compared. The most significant bit in each
4301element is 1 if the element-wise comparison evaluates to true, and is 0
4302otherwise. All other bits of the result are undefined. The condition codes
4303are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4304instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4305
4306<h5>Example:</h5>
4307<pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4308 &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>
4309 &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]4310</pre>
4311</div>
4312
4313<!-- _______________________________________________________________________ -->
4314<div class="doc_subsubsection">
4315 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
4316</div>
4317<div class="doc_text">
4318<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4319<pre> &lt;result&gt; = vfcmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt;</pre>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4320<h5>Overview:</h5>
4321<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
4322element-wise comparison of its two floating point vector operands. The output
4323elements have the same width as the input elements.</p>
4324<h5>Arguments:</h5>
4325<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
4326the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4327a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4328<ol>
4329 <li><tt>false</tt>: no comparison, always returns false</li>
4330 <li><tt>oeq</tt>: ordered and equal</li>
4331 <li><tt>ogt</tt>: ordered and greater than </li>
4332 <li><tt>oge</tt>: ordered and greater than or equal</li>
4333 <li><tt>olt</tt>: ordered and less than </li>
4334 <li><tt>ole</tt>: ordered and less than or equal</li>
4335 <li><tt>one</tt>: ordered and not equal</li>
4336 <li><tt>ord</tt>: ordered (no nans)</li>
4337 <li><tt>ueq</tt>: unordered or equal</li>
4338 <li><tt>ugt</tt>: unordered or greater than </li>
4339 <li><tt>uge</tt>: unordered or greater than or equal</li>
4340 <li><tt>ult</tt>: unordered or less than </li>
4341 <li><tt>ule</tt>: unordered or less than or equal</li>
4342 <li><tt>une</tt>: unordered or not equal</li>
4343 <li><tt>uno</tt>: unordered (either nans)</li>
4344 <li><tt>true</tt>: no comparison, always returns true</li>
4345</ol>
4346<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4347<a href="#t_floating">floating point</a> typed. They must also be identical
4348types.</p>
4349<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4350<p>The '<tt>vfcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4351according to the condition code given as <tt>cond</tt>. The comparison yields a
4352<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4353an identical number of elements as the values being compared, and each element
4354having identical with to the width of the floating point elements. The most
4355significant bit in each element is 1 if the element-wise comparison evaluates to
4356true, and is 0 otherwise. All other bits of the result are undefined. The
4357condition codes are evaluated identically to the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4358<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4359
4360<h5>Example:</h5>
4361<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]4362 <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4363 &lt;result&gt; = vfcmp oeq &lt;2 x float&gt; &lt; float 4, float 0 &gt;, &lt; float 5, float 0 &gt;
4364
4365 <i>; yields: result=&lt;2 x i64&gt; &lt; i64 -1, i64 0 &gt;</i>
4366 &lt;result&gt; = vfcmp ult &lt;2 x double&gt; &lt; double 1, double 2 &gt;, &lt; double 2, double 2&gt;
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4367</pre>
4368</div>
4369
4370<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4371<div class="doc_subsubsection">
4372 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4373</div>
4374
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4375<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4376
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4377<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4378
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4379<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4380<h5>Overview:</h5>
4381<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4382the SSA graph representing the function.</p>
4383<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4384
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4385<p>The type of the incoming values is specified with the first type
4386field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4387as arguments, with one pair for each predecessor basic block of the
4388current block. Only values of <a href="#t_firstclass">first class</a>
4389type may be used as the value arguments to the PHI node. Only labels
4390may be used as the label arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4391
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4392<p>There must be no non-phi instructions between the start of a basic
4393block and the PHI instructions: i.e. PHI instructions must be first in
4394a basic block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4395
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4396<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4397
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4398<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4399specified by the pair corresponding to the predecessor basic block that executed
4400just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4401
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4402<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4403<pre>
4404Loop: ; Infinite loop that counts from 0 on up...
4405 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4406 %nextindvar = add i32 %indvar, 1
4407 br label %Loop
4408</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4409</div>
4410
4411<!-- _______________________________________________________________________ -->
4412<div class="doc_subsubsection">
4413 <a name="i_select">'<tt>select</tt>' Instruction</a>
4414</div>
4415
4416<div class="doc_text">
4417
4418<h5>Syntax:</h5>
4419
4420<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4421 &lt;result&gt; = select <i>selty</i> &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
4422
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4423 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4424</pre>
4425
4426<h5>Overview:</h5>
4427
4428<p>
4429The '<tt>select</tt>' instruction is used to choose one value based on a
4430condition, without branching.
4431</p>
4432
4433
4434<h5>Arguments:</h5>
4435
4436<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4437The '<tt>select</tt>' instruction requires an 'i1' value or
4438a vector of 'i1' values indicating the
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4439condition, and two values of the same <a href="#t_firstclass">first class</a>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4440type. If the val1/val2 are vectors and
4441the condition is a scalar, then entire vectors are selected, not
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4442individual elements.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4443</p>
4444
4445<h5>Semantics:</h5>
4446
4447<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4448If the condition is an i1 and it evaluates to 1, the instruction returns the first
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4449value argument; otherwise, it returns the second value argument.
4450</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4451<p>
4452If the condition is a vector of i1, then the value arguments must
4453be vectors of the same size, and the selection is done element
4454by element.
4455</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4456
4457<h5>Example:</h5>
4458
4459<pre>
4460 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4461</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4462
4463<p>Note that the code generator does not yet support conditions
4464 with vector type.</p>
4465
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4466</div>
4467
4468
4469<!-- _______________________________________________________________________ -->
4470<div class="doc_subsubsection">
4471 <a name="i_call">'<tt>call</tt>' Instruction</a>
4472</div>
4473
4474<div class="doc_text">
4475
4476<h5>Syntax:</h5>
4477<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4478 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ty&gt; [&lt;fnty&gt;*] &lt;fnptrval&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4479</pre>
4480
4481<h5>Overview:</h5>
4482
4483<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4484
4485<h5>Arguments:</h5>
4486
4487<p>This instruction requires several arguments:</p>
4488
4489<ol>
4490 <li>
4491 <p>The optional "tail" marker indicates whether the callee function accesses
4492 any allocas or varargs in the caller. If the "tail" marker is present, the
4493 function call is eligible for tail call optimization. Note that calls may
4494 be marked "tail" even if they do not occur before a <a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4495 href="#i_ret"><tt>ret</tt></a> instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4496 </li>
4497 <li>
4498 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
4499 convention</a> the call should use. If none is specified, the call defaults
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4500 to using C calling conventions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4501 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4502
4503 <li>
4504 <p>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4505 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
4506 and '<tt>inreg</tt>' attributes are valid here.</p>
4507 </li>
4508
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4509 <li>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4510 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4511 the type of the return value. Functions that return no value are marked
4512 <tt><a href="#t_void">void</a></tt>.</p>
4513 </li>
4514 <li>
4515 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4516 value being invoked. The argument types must match the types implied by
4517 this signature. This type can be omitted if the function is not varargs
4518 and if the function type does not return a pointer to a function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4519 </li>
4520 <li>
4521 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4522 be invoked. In most cases, this is a direct function invocation, but
4523 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4524 to function value.</p>
4525 </li>
4526 <li>
4527 <p>'<tt>function args</tt>': argument list whose types match the
4528 function signature argument types. All arguments must be of
4529 <a href="#t_firstclass">first class</a> type. If the function signature
4530 indicates the function accepts a variable number of arguments, the extra
4531 arguments can be specified.</p>
4532 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4533 <li>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4534 <p>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4535 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4536 '<tt>readnone</tt>' attributes are valid here.</p>
4537 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4538</ol>
4539
4540<h5>Semantics:</h5>
4541
4542<p>The '<tt>call</tt>' instruction is used to cause control flow to
4543transfer to a specified function, with its incoming arguments bound to
4544the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4545instruction in the called function, control flow continues with the
4546instruction after the function call, and the return value of the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4547function is bound to the result argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4548
4549<h5>Example:</h5>
4550
4551<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4552 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4553 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4554 %X = tail call i32 @foo() <i>; yields i32</i>
4555 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4556 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4557
4558 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4559 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]4560 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4561 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]4562 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]4563 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4564</pre>
4565
4566</div>
4567
4568<!-- _______________________________________________________________________ -->
4569<div class="doc_subsubsection">
4570 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4571</div>
4572
4573<div class="doc_text">
4574
4575<h5>Syntax:</h5>
4576
4577<pre>
4578 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4579</pre>
4580
4581<h5>Overview:</h5>
4582
4583<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
4584the "variable argument" area of a function call. It is used to implement the
4585<tt>va_arg</tt> macro in C.</p>
4586
4587<h5>Arguments:</h5>
4588
4589<p>This instruction takes a <tt>va_list*</tt> value and the type of
4590the argument. It returns a value of the specified argument type and
4591increments the <tt>va_list</tt> to point to the next argument. The
4592actual type of <tt>va_list</tt> is target specific.</p>
4593
4594<h5>Semantics:</h5>
4595
4596<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4597type from the specified <tt>va_list</tt> and causes the
4598<tt>va_list</tt> to point to the next argument. For more information,
4599see the variable argument handling <a href="#int_varargs">Intrinsic
4600Functions</a>.</p>
4601
4602<p>It is legal for this instruction to be called in a function which does not
4603take a variable number of arguments, for example, the <tt>vfprintf</tt>
4604function.</p>
4605
4606<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
4607href="#intrinsics">intrinsic function</a> because it takes a type as an
4608argument.</p>
4609
4610<h5>Example:</h5>
4611
4612<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4613
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]4614<p>Note that the code generator does not yet fully support va_arg
4615 on many targets. Also, it does not currently support va_arg with
4616 aggregate types on any target.</p>
4617
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4618</div>
4619
4620<!-- *********************************************************************** -->
4621<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4622<!-- *********************************************************************** -->
4623
4624<div class="doc_text">
4625
4626<p>LLVM supports the notion of an "intrinsic function". These functions have
4627well known names and semantics and are required to follow certain restrictions.
4628Overall, these intrinsics represent an extension mechanism for the LLVM
4629language that does not require changing all of the transformations in LLVM when
4630adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
4631
4632<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
4633prefix is reserved in LLVM for intrinsic names; thus, function names may not
4634begin with this prefix. Intrinsic functions must always be external functions:
4635you cannot define the body of intrinsic functions. Intrinsic functions may
4636only be used in call or invoke instructions: it is illegal to take the address
4637of an intrinsic function. Additionally, because intrinsic functions are part
4638of the LLVM language, it is required if any are added that they be documented
4639here.</p>
4640
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4641<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4642a family of functions that perform the same operation but on different data
4643types. Because LLVM can represent over 8 million different integer types,
4644overloading is used commonly to allow an intrinsic function to operate on any
4645integer type. One or more of the argument types or the result type can be
4646overloaded to accept any integer type. Argument types may also be defined as
4647exactly matching a previous argument's type or the result type. This allows an
4648intrinsic function which accepts multiple arguments, but needs all of them to
4649be of the same type, to only be overloaded with respect to a single argument or
4650the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4651
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4652<p>Overloaded intrinsics will have the names of its overloaded argument types
4653encoded into its function name, each preceded by a period. Only those types
4654which are overloaded result in a name suffix. Arguments whose type is matched
4655against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4656take an integer of any width and returns an integer of exactly the same integer
4657width. This leads to a family of functions such as
4658<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4659Only one type, the return type, is overloaded, and only one type suffix is
4660required. Because the argument's type is matched against the return type, it
4661does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4662
4663<p>To learn how to add an intrinsic function, please see the
4664<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
4665</p>
4666
4667</div>
4668
4669<!-- ======================================================================= -->
4670<div class="doc_subsection">
4671 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4672</div>
4673
4674<div class="doc_text">
4675
4676<p>Variable argument support is defined in LLVM with the <a
4677 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4678intrinsic functions. These functions are related to the similarly
4679named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
4680
4681<p>All of these functions operate on arguments that use a
4682target-specific value type "<tt>va_list</tt>". The LLVM assembly
4683language reference manual does not define what this type is, so all
4684transformations should be prepared to handle these functions regardless of
4685the type used.</p>
4686
4687<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
4688instruction and the variable argument handling intrinsic functions are
4689used.</p>
4690
4691<div class="doc_code">
4692<pre>
4693define i32 @test(i32 %X, ...) {
4694 ; Initialize variable argument processing
4695 %ap = alloca i8*
4696 %ap2 = bitcast i8** %ap to i8*
4697 call void @llvm.va_start(i8* %ap2)
4698
4699 ; Read a single integer argument
4700 %tmp = va_arg i8** %ap, i32
4701
4702 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4703 %aq = alloca i8*
4704 %aq2 = bitcast i8** %aq to i8*
4705 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4706 call void @llvm.va_end(i8* %aq2)
4707
4708 ; Stop processing of arguments.
4709 call void @llvm.va_end(i8* %ap2)
4710 ret i32 %tmp
4711}
4712
4713declare void @llvm.va_start(i8*)
4714declare void @llvm.va_copy(i8*, i8*)
4715declare void @llvm.va_end(i8*)
4716</pre>
4717</div>
4718
4719</div>
4720
4721<!-- _______________________________________________________________________ -->
4722<div class="doc_subsubsection">
4723 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4724</div>
4725
4726
4727<div class="doc_text">
4728<h5>Syntax:</h5>
4729<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
4730<h5>Overview:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4731<p>The '<tt>llvm.va_start</tt>' intrinsic initializes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4732<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4733href="#i_va_arg">va_arg</a></tt>.</p>
4734
4735<h5>Arguments:</h5>
4736
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4737<p>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4738
4739<h5>Semantics:</h5>
4740
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4741<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4742macro available in C. In a target-dependent way, it initializes the
4743<tt>va_list</tt> element to which the argument points, so that the next call to
4744<tt>va_arg</tt> will produce the first variable argument passed to the function.
4745Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
4746last argument of the function as the compiler can figure that out.</p>
4747
4748</div>
4749
4750<!-- _______________________________________________________________________ -->
4751<div class="doc_subsubsection">
4752 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
4753</div>
4754
4755<div class="doc_text">
4756<h5>Syntax:</h5>
4757<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
4758<h5>Overview:</h5>
4759
4760<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
4761which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
4762or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
4763
4764<h5>Arguments:</h5>
4765
4766<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
4767
4768<h5>Semantics:</h5>
4769
4770<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
4771macro available in C. In a target-dependent way, it destroys the
4772<tt>va_list</tt> element to which the argument points. Calls to <a
4773href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4774<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4775<tt>llvm.va_end</tt>.</p>
4776
4777</div>
4778
4779<!-- _______________________________________________________________________ -->
4780<div class="doc_subsubsection">
4781 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
4782</div>
4783
4784<div class="doc_text">
4785
4786<h5>Syntax:</h5>
4787
4788<pre>
4789 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
4790</pre>
4791
4792<h5>Overview:</h5>
4793
4794<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4795from the source argument list to the destination argument list.</p>
4796
4797<h5>Arguments:</h5>
4798
4799<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
4800The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
4801
4802
4803<h5>Semantics:</h5>
4804
4805<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4806macro available in C. In a target-dependent way, it copies the source
4807<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4808intrinsic is necessary because the <tt><a href="#int_va_start">
4809llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4810example, memory allocation.</p>
4811
4812</div>
4813
4814<!-- ======================================================================= -->
4815<div class="doc_subsection">
4816 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4817</div>
4818
4819<div class="doc_text">
4820
4821<p>
4822LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]4823Collection</a> (GC) requires the implementation and generation of these
4824intrinsics.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4825These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
4826stack</a>, as well as garbage collector implementations that require <a
4827href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
4828Front-ends for type-safe garbage collected languages should generate these
4829intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4830href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4831</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]4832
4833<p>The garbage collection intrinsics only operate on objects in the generic
4834 address space (address space zero).</p>
4835
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4836</div>
4837
4838<!-- _______________________________________________________________________ -->
4839<div class="doc_subsubsection">
4840 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
4841</div>
4842
4843<div class="doc_text">
4844
4845<h5>Syntax:</h5>
4846
4847<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4848 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4849</pre>
4850
4851<h5>Overview:</h5>
4852
4853<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
4854the code generator, and allows some metadata to be associated with it.</p>
4855
4856<h5>Arguments:</h5>
4857
4858<p>The first argument specifies the address of a stack object that contains the
4859root pointer. The second pointer (which must be either a constant or a global
4860value address) contains the meta-data to be associated with the root.</p>
4861
4862<h5>Semantics:</h5>
4863
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]4864<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]4865location. At compile-time, the code generator generates information to allow
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4866the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4867intrinsic may only be used in a function which <a href="#gc">specifies a GC
4868algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4869
4870</div>
4871
4872
4873<!-- _______________________________________________________________________ -->
4874<div class="doc_subsubsection">
4875 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
4876</div>
4877
4878<div class="doc_text">
4879
4880<h5>Syntax:</h5>
4881
4882<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4883 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4884</pre>
4885
4886<h5>Overview:</h5>
4887
4888<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4889locations, allowing garbage collector implementations that require read
4890barriers.</p>
4891
4892<h5>Arguments:</h5>
4893
4894<p>The second argument is the address to read from, which should be an address
4895allocated from the garbage collector. The first object is a pointer to the
4896start of the referenced object, if needed by the language runtime (otherwise
4897null).</p>
4898
4899<h5>Semantics:</h5>
4900
4901<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4902instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4903garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4904may only be used in a function which <a href="#gc">specifies a GC
4905algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4906
4907</div>
4908
4909
4910<!-- _______________________________________________________________________ -->
4911<div class="doc_subsubsection">
4912 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
4913</div>
4914
4915<div class="doc_text">
4916
4917<h5>Syntax:</h5>
4918
4919<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4920 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4921</pre>
4922
4923<h5>Overview:</h5>
4924
4925<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4926locations, allowing garbage collector implementations that require write
4927barriers (such as generational or reference counting collectors).</p>
4928
4929<h5>Arguments:</h5>
4930
4931<p>The first argument is the reference to store, the second is the start of the
4932object to store it to, and the third is the address of the field of Obj to
4933store to. If the runtime does not require a pointer to the object, Obj may be
4934null.</p>
4935
4936<h5>Semantics:</h5>
4937
4938<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4939instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4940garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4941may only be used in a function which <a href="#gc">specifies a GC
4942algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4943
4944</div>
4945
4946
4947
4948<!-- ======================================================================= -->
4949<div class="doc_subsection">
4950 <a name="int_codegen">Code Generator Intrinsics</a>
4951</div>
4952
4953<div class="doc_text">
4954<p>
4955These intrinsics are provided by LLVM to expose special features that may only
4956be implemented with code generator support.
4957</p>
4958
4959</div>
4960
4961<!-- _______________________________________________________________________ -->
4962<div class="doc_subsubsection">
4963 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
4964</div>
4965
4966<div class="doc_text">
4967
4968<h5>Syntax:</h5>
4969<pre>
4970 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
4971</pre>
4972
4973<h5>Overview:</h5>
4974
4975<p>
4976The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4977target-specific value indicating the return address of the current function
4978or one of its callers.
4979</p>
4980
4981<h5>Arguments:</h5>
4982
4983<p>
4984The argument to this intrinsic indicates which function to return the address
4985for. Zero indicates the calling function, one indicates its caller, etc. The
4986argument is <b>required</b> to be a constant integer value.
4987</p>
4988
4989<h5>Semantics:</h5>
4990
4991<p>
4992The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4993the return address of the specified call frame, or zero if it cannot be
4994identified. The value returned by this intrinsic is likely to be incorrect or 0
4995for arguments other than zero, so it should only be used for debugging purposes.
4996</p>
4997
4998<p>
4999Note that calling this intrinsic does not prevent function inlining or other
5000aggressive transformations, so the value returned may not be that of the obvious
5001source-language caller.
5002</p>
5003</div>
5004
5005
5006<!-- _______________________________________________________________________ -->
5007<div class="doc_subsubsection">
5008 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5009</div>
5010
5011<div class="doc_text">
5012
5013<h5>Syntax:</h5>
5014<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5015 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5016</pre>
5017
5018<h5>Overview:</h5>
5019
5020<p>
5021The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5022target-specific frame pointer value for the specified stack frame.
5023</p>
5024
5025<h5>Arguments:</h5>
5026
5027<p>
5028The argument to this intrinsic indicates which function to return the frame
5029pointer for. Zero indicates the calling function, one indicates its caller,
5030etc. The argument is <b>required</b> to be a constant integer value.
5031</p>
5032
5033<h5>Semantics:</h5>
5034
5035<p>
5036The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
5037the frame address of the specified call frame, or zero if it cannot be
5038identified. The value returned by this intrinsic is likely to be incorrect or 0
5039for arguments other than zero, so it should only be used for debugging purposes.
5040</p>
5041
5042<p>
5043Note that calling this intrinsic does not prevent function inlining or other
5044aggressive transformations, so the value returned may not be that of the obvious
5045source-language caller.
5046</p>
5047</div>
5048
5049<!-- _______________________________________________________________________ -->
5050<div class="doc_subsubsection">
5051 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5052</div>
5053
5054<div class="doc_text">
5055
5056<h5>Syntax:</h5>
5057<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5058 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5059</pre>
5060
5061<h5>Overview:</h5>
5062
5063<p>
5064The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
5065the function stack, for use with <a href="#int_stackrestore">
5066<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
5067features like scoped automatic variable sized arrays in C99.
5068</p>
5069
5070<h5>Semantics:</h5>
5071
5072<p>
5073This intrinsic returns a opaque pointer value that can be passed to <a
5074href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
5075<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
5076<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
5077state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
5078practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
5079that were allocated after the <tt>llvm.stacksave</tt> was executed.
5080</p>
5081
5082</div>
5083
5084<!-- _______________________________________________________________________ -->
5085<div class="doc_subsubsection">
5086 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5087</div>
5088
5089<div class="doc_text">
5090
5091<h5>Syntax:</h5>
5092<pre>
5093 declare void @llvm.stackrestore(i8 * %ptr)
5094</pre>
5095
5096<h5>Overview:</h5>
5097
5098<p>
5099The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5100the function stack to the state it was in when the corresponding <a
5101href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
5102useful for implementing language features like scoped automatic variable sized
5103arrays in C99.
5104</p>
5105
5106<h5>Semantics:</h5>
5107
5108<p>
5109See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
5110</p>
5111
5112</div>
5113
5114
5115<!-- _______________________________________________________________________ -->
5116<div class="doc_subsubsection">
5117 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5118</div>
5119
5120<div class="doc_text">
5121
5122<h5>Syntax:</h5>
5123<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5124 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]5125</pre>
5126
5127<h5>Overview:</h5>
5128
5129
5130<p>
5131The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
5132a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
5133no
5134effect on the behavior of the program but can change its performance
5135characteristics.
5136</p>
5137
5138<h5>Arguments:</h5>
5139
5140<p>
5141<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
5142determining if the fetch should be for a read (0) or write (1), and
5143<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5144locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
5145<tt>locality</tt> arguments must be constant integers.
5146</p>
5147
5148<h5>Semantics:</h5>
5149
5150<p>
5151This intrinsic does not modify the behavior of the program. In particular,
5152prefetches cannot trap and do not produce a value. On targets that support this
5153intrinsic, the prefetch can provide hints to the processor cache for better
5154performance.
5155</p>
5156
5157</div>
5158
5159<!-- _______________________________________________________________________ -->
5160<div class="doc_subsubsection">
5161 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5162</div>
5163
5164<div class="doc_text">
5165
5166<h5>Syntax:</h5>
5167<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5168 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5169</pre>
5170
5171<h5>Overview:</h5>
5172
5173
5174<p>
5175The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5176(PC) in a region of
5177code to simulators and other tools. The method is target specific, but it is
5178expected that the marker will use exported symbols to transmit the PC of the
5179marker.
5180The marker makes no guarantees that it will remain with any specific instruction
5181after optimizations. It is possible that the presence of a marker will inhibit
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5182optimizations. The intended use is to be inserted after optimizations to allow
5183correlations of simulation runs.
5184</p>
5185
5186<h5>Arguments:</h5>
5187
5188<p>
5189<tt>id</tt> is a numerical id identifying the marker.
5190</p>
5191
5192<h5>Semantics:</h5>
5193
5194<p>
5195This intrinsic does not modify the behavior of the program. Backends that do not
5196support this intrinisic may ignore it.
5197</p>
5198
5199</div>
5200
5201<!-- _______________________________________________________________________ -->
5202<div class="doc_subsubsection">
5203 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5204</div>
5205
5206<div class="doc_text">
5207
5208<h5>Syntax:</h5>
5209<pre>
5210 declare i64 @llvm.readcyclecounter( )
5211</pre>
5212
5213<h5>Overview:</h5>
5214
5215
5216<p>
5217The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5218counter register (or similar low latency, high accuracy clocks) on those targets
5219that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
5220As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
5221should only be used for small timings.
5222</p>
5223
5224<h5>Semantics:</h5>
5225
5226<p>
5227When directly supported, reading the cycle counter should not modify any memory.
5228Implementations are allowed to either return a application specific value or a
5229system wide value. On backends without support, this is lowered to a constant 0.
5230</p>
5231
5232</div>
5233
5234<!-- ======================================================================= -->
5235<div class="doc_subsection">
5236 <a name="int_libc">Standard C Library Intrinsics</a>
5237</div>
5238
5239<div class="doc_text">
5240<p>
5241LLVM provides intrinsics for a few important standard C library functions.
5242These intrinsics allow source-language front-ends to pass information about the
5243alignment of the pointer arguments to the code generator, providing opportunity
5244for more efficient code generation.
5245</p>
5246
5247</div>
5248
5249<!-- _______________________________________________________________________ -->
5250<div class="doc_subsubsection">
5251 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5252</div>
5253
5254<div class="doc_text">
5255
5256<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5257<p>This is an overloaded intrinsic. You can use llvm.memcpy on any integer bit
5258width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5259<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5260 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5261 i8 &lt;len&gt;, i32 &lt;align&gt;)
5262 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5263 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5264 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5265 i32 &lt;len&gt;, i32 &lt;align&gt;)
5266 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5267 i64 &lt;len&gt;, i32 &lt;align&gt;)
5268</pre>
5269
5270<h5>Overview:</h5>
5271
5272<p>
5273The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5274location to the destination location.
5275</p>
5276
5277<p>
5278Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5279intrinsics do not return a value, and takes an extra alignment argument.
5280</p>
5281
5282<h5>Arguments:</h5>
5283
5284<p>
5285The first argument is a pointer to the destination, the second is a pointer to
5286the source. The third argument is an integer argument
5287specifying the number of bytes to copy, and the fourth argument is the alignment
5288of the source and destination locations.
5289</p>
5290
5291<p>
5292If the call to this intrinisic has an alignment value that is not 0 or 1, then
5293the caller guarantees that both the source and destination pointers are aligned
5294to that boundary.
5295</p>
5296
5297<h5>Semantics:</h5>
5298
5299<p>
5300The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5301location to the destination location, which are not allowed to overlap. It
5302copies "len" bytes of memory over. If the argument is known to be aligned to
5303some boundary, this can be specified as the fourth argument, otherwise it should
5304be set to 0 or 1.
5305</p>
5306</div>
5307
5308
5309<!-- _______________________________________________________________________ -->
5310<div class="doc_subsubsection">
5311 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5312</div>
5313
5314<div class="doc_text">
5315
5316<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5317<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
5318width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5319<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5320 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5321 i8 &lt;len&gt;, i32 &lt;align&gt;)
5322 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5323 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5324 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5325 i32 &lt;len&gt;, i32 &lt;align&gt;)
5326 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5327 i64 &lt;len&gt;, i32 &lt;align&gt;)
5328</pre>
5329
5330<h5>Overview:</h5>
5331
5332<p>
5333The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5334location to the destination location. It is similar to the
Chris Lattnerdba16ea2008-01-06 19:51:52 +0000[diff] [blame]5335'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5336</p>
5337
5338<p>
5339Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5340intrinsics do not return a value, and takes an extra alignment argument.
5341</p>
5342
5343<h5>Arguments:</h5>
5344
5345<p>
5346The first argument is a pointer to the destination, the second is a pointer to
5347the source. The third argument is an integer argument
5348specifying the number of bytes to copy, and the fourth argument is the alignment
5349of the source and destination locations.
5350</p>
5351
5352<p>
5353If the call to this intrinisic has an alignment value that is not 0 or 1, then
5354the caller guarantees that the source and destination pointers are aligned to
5355that boundary.
5356</p>
5357
5358<h5>Semantics:</h5>
5359
5360<p>
5361The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
5362location to the destination location, which may overlap. It
5363copies "len" bytes of memory over. If the argument is known to be aligned to
5364some boundary, this can be specified as the fourth argument, otherwise it should
5365be set to 0 or 1.
5366</p>
5367</div>
5368
5369
5370<!-- _______________________________________________________________________ -->
5371<div class="doc_subsubsection">
5372 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5373</div>
5374
5375<div class="doc_text">
5376
5377<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5378<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
5379width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5380<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5381 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5382 i8 &lt;len&gt;, i32 &lt;align&gt;)
5383 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5384 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5385 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5386 i32 &lt;len&gt;, i32 &lt;align&gt;)
5387 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5388 i64 &lt;len&gt;, i32 &lt;align&gt;)
5389</pre>
5390
5391<h5>Overview:</h5>
5392
5393<p>
5394The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
5395byte value.
5396</p>
5397
5398<p>
5399Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5400does not return a value, and takes an extra alignment argument.
5401</p>
5402
5403<h5>Arguments:</h5>
5404
5405<p>
5406The first argument is a pointer to the destination to fill, the second is the
5407byte value to fill it with, the third argument is an integer
5408argument specifying the number of bytes to fill, and the fourth argument is the
5409known alignment of destination location.
5410</p>
5411
5412<p>
5413If the call to this intrinisic has an alignment value that is not 0 or 1, then
5414the caller guarantees that the destination pointer is aligned to that boundary.
5415</p>
5416
5417<h5>Semantics:</h5>
5418
5419<p>
5420The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5421the
5422destination location. If the argument is known to be aligned to some boundary,
5423this can be specified as the fourth argument, otherwise it should be set to 0 or
54241.
5425</p>
5426</div>
5427
5428
5429<!-- _______________________________________________________________________ -->
5430<div class="doc_subsubsection">
5431 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5432</div>
5433
5434<div class="doc_text">
5435
5436<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5437<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]5438floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5439types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5440<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5441 declare float @llvm.sqrt.f32(float %Val)
5442 declare double @llvm.sqrt.f64(double %Val)
5443 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5444 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5445 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5446</pre>
5447
5448<h5>Overview:</h5>
5449
5450<p>
5451The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5452returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5453<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattnerf914a002008-01-29 07:00:44 +0000[diff] [blame]5454negative numbers other than -0.0 (which allows for better optimization, because
5455there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5456defined to return -0.0 like IEEE sqrt.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5457</p>
5458
5459<h5>Arguments:</h5>
5460
5461<p>
5462The argument and return value are floating point numbers of the same type.
5463</p>
5464
5465<h5>Semantics:</h5>
5466
5467<p>
5468This function returns the sqrt of the specified operand if it is a nonnegative
5469floating point number.
5470</p>
5471</div>
5472
5473<!-- _______________________________________________________________________ -->
5474<div class="doc_subsubsection">
5475 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5476</div>
5477
5478<div class="doc_text">
5479
5480<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5481<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]5482floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5483types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5484<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5485 declare float @llvm.powi.f32(float %Val, i32 %power)
5486 declare double @llvm.powi.f64(double %Val, i32 %power)
5487 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5488 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5489 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5490</pre>
5491
5492<h5>Overview:</h5>
5493
5494<p>
5495The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5496specified (positive or negative) power. The order of evaluation of
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5497multiplications is not defined. When a vector of floating point type is
5498used, the second argument remains a scalar integer value.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5499</p>
5500
5501<h5>Arguments:</h5>
5502
5503<p>
5504The second argument is an integer power, and the first is a value to raise to
5505that power.
5506</p>
5507
5508<h5>Semantics:</h5>
5509
5510<p>
5511This function returns the first value raised to the second power with an
5512unspecified sequence of rounding operations.</p>
5513</div>
5514
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5515<!-- _______________________________________________________________________ -->
5516<div class="doc_subsubsection">
5517 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5518</div>
5519
5520<div class="doc_text">
5521
5522<h5>Syntax:</h5>
5523<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5524floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5525types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5526<pre>
5527 declare float @llvm.sin.f32(float %Val)
5528 declare double @llvm.sin.f64(double %Val)
5529 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5530 declare fp128 @llvm.sin.f128(fp128 %Val)
5531 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5532</pre>
5533
5534<h5>Overview:</h5>
5535
5536<p>
5537The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5538</p>
5539
5540<h5>Arguments:</h5>
5541
5542<p>
5543The argument and return value are floating point numbers of the same type.
5544</p>
5545
5546<h5>Semantics:</h5>
5547
5548<p>
5549This function returns the sine of the specified operand, returning the
5550same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5551conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5552</div>
5553
5554<!-- _______________________________________________________________________ -->
5555<div class="doc_subsubsection">
5556 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5557</div>
5558
5559<div class="doc_text">
5560
5561<h5>Syntax:</h5>
5562<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5563floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5564types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5565<pre>
5566 declare float @llvm.cos.f32(float %Val)
5567 declare double @llvm.cos.f64(double %Val)
5568 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5569 declare fp128 @llvm.cos.f128(fp128 %Val)
5570 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5571</pre>
5572
5573<h5>Overview:</h5>
5574
5575<p>
5576The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5577</p>
5578
5579<h5>Arguments:</h5>
5580
5581<p>
5582The argument and return value are floating point numbers of the same type.
5583</p>
5584
5585<h5>Semantics:</h5>
5586
5587<p>
5588This function returns the cosine of the specified operand, returning the
5589same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5590conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5591</div>
5592
5593<!-- _______________________________________________________________________ -->
5594<div class="doc_subsubsection">
5595 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5596</div>
5597
5598<div class="doc_text">
5599
5600<h5>Syntax:</h5>
5601<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5602floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5603types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5604<pre>
5605 declare float @llvm.pow.f32(float %Val, float %Power)
5606 declare double @llvm.pow.f64(double %Val, double %Power)
5607 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5608 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5609 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5610</pre>
5611
5612<h5>Overview:</h5>
5613
5614<p>
5615The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5616specified (positive or negative) power.
5617</p>
5618
5619<h5>Arguments:</h5>
5620
5621<p>
5622The second argument is a floating point power, and the first is a value to
5623raise to that power.
5624</p>
5625
5626<h5>Semantics:</h5>
5627
5628<p>
5629This function returns the first value raised to the second power,
5630returning the
5631same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5632conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5633</div>
5634
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5635
5636<!-- ======================================================================= -->
5637<div class="doc_subsection">
5638 <a name="int_manip">Bit Manipulation Intrinsics</a>
5639</div>
5640
5641<div class="doc_text">
5642<p>
5643LLVM provides intrinsics for a few important bit manipulation operations.
5644These allow efficient code generation for some algorithms.
5645</p>
5646
5647</div>
5648
5649<!-- _______________________________________________________________________ -->
5650<div class="doc_subsubsection">
5651 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5652</div>
5653
5654<div class="doc_text">
5655
5656<h5>Syntax:</h5>
5657<p>This is an overloaded intrinsic function. You can use bswap on any integer
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5658type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5659<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5660 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5661 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5662 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5663</pre>
5664
5665<h5>Overview:</h5>
5666
5667<p>
5668The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5669values with an even number of bytes (positive multiple of 16 bits). These are
5670useful for performing operations on data that is not in the target's native
5671byte order.
5672</p>
5673
5674<h5>Semantics:</h5>
5675
5676<p>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5677The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5678and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5679intrinsic returns an i32 value that has the four bytes of the input i32
5680swapped, 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]5681i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5682<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5683additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
5684</p>
5685
5686</div>
5687
5688<!-- _______________________________________________________________________ -->
5689<div class="doc_subsubsection">
5690 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5691</div>
5692
5693<div class="doc_text">
5694
5695<h5>Syntax:</h5>
5696<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5697width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5698<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame^]5699 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5700 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5701 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5702 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5703 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5704</pre>
5705
5706<h5>Overview:</h5>
5707
5708<p>
5709The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5710value.
5711</p>
5712
5713<h5>Arguments:</h5>
5714
5715<p>
5716The only argument is the value to be counted. The argument may be of any
5717integer type. The return type must match the argument type.
5718</p>
5719
5720<h5>Semantics:</h5>
5721
5722<p>
5723The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5724</p>
5725</div>
5726
5727<!-- _______________________________________________________________________ -->
5728<div class="doc_subsubsection">
5729 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5730</div>
5731
5732<div class="doc_text">
5733
5734<h5>Syntax:</h5>
5735<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5736integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5737<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5738 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5739 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5740 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5741 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5742 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5743</pre>
5744
5745<h5>Overview:</h5>
5746
5747<p>
5748The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5749leading zeros in a variable.
5750</p>
5751
5752<h5>Arguments:</h5>
5753
5754<p>
5755The only argument is the value to be counted. The argument may be of any
5756integer type. The return type must match the argument type.
5757</p>
5758
5759<h5>Semantics:</h5>
5760
5761<p>
5762The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5763in a variable. If the src == 0 then the result is the size in bits of the type
5764of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
5765</p>
5766</div>
5767
5768
5769
5770<!-- _______________________________________________________________________ -->
5771<div class="doc_subsubsection">
5772 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5773</div>
5774
5775<div class="doc_text">
5776
5777<h5>Syntax:</h5>
5778<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5779integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5780<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5781 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5782 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5783 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5784 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5785 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5786</pre>
5787
5788<h5>Overview:</h5>
5789
5790<p>
5791The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5792trailing zeros.
5793</p>
5794
5795<h5>Arguments:</h5>
5796
5797<p>
5798The only argument is the value to be counted. The argument may be of any
5799integer type. The return type must match the argument type.
5800</p>
5801
5802<h5>Semantics:</h5>
5803
5804<p>
5805The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5806in a variable. If the src == 0 then the result is the size in bits of the type
5807of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5808</p>
5809</div>
5810
5811<!-- _______________________________________________________________________ -->
5812<div class="doc_subsubsection">
5813 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
5814</div>
5815
5816<div class="doc_text">
5817
5818<h5>Syntax:</h5>
5819<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5820on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5821<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5822 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5823 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5824</pre>
5825
5826<h5>Overview:</h5>
5827<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
5828range of bits from an integer value and returns them in the same bit width as
5829the original value.</p>
5830
5831<h5>Arguments:</h5>
5832<p>The first argument, <tt>%val</tt> and the result may be integer types of
5833any bit width but they must have the same bit width. The second and third
5834arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
5835
5836<h5>Semantics:</h5>
5837<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
5838of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5839<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5840operates in forward mode.</p>
5841<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5842right by <tt>%loBit</tt> bits and then ANDing it with a mask with
5843only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5844<ol>
5845 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5846 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5847 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5848 to determine the number of bits to retain.</li>
5849 <li>A mask of the retained bits is created by shifting a -1 value.</li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5850 <li>The mask is ANDed with <tt>%val</tt> to produce the result.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5851</ol>
5852<p>In reverse mode, a similar computation is made except that the bits are
5853returned in the reverse order. So, for example, if <tt>X</tt> has the value
5854<tt>i16 0x0ACF (101011001111)</tt> and we apply
5855<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5856<tt>i16 0x0026 (000000100110)</tt>.</p>
5857</div>
5858
5859<div class="doc_subsubsection">
5860 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5861</div>
5862
5863<div class="doc_text">
5864
5865<h5>Syntax:</h5>
5866<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5867on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5868<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5869 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5870 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]5871</pre>
5872
5873<h5>Overview:</h5>
5874<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5875of bits in an integer value with another integer value. It returns the integer
5876with the replaced bits.</p>
5877
5878<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame^]5879<p>The first argument, <tt>%val</tt>, and the result may be integer types of
5880any bit width, but they must have the same bit width. <tt>%val</tt> is the value
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5881whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5882integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5883type since they specify only a bit index.</p>
5884
5885<h5>Semantics:</h5>
5886<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5887of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5888<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5889operates in forward mode.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame^]5890
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5891<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5892truncating it down to the size of the replacement area or zero extending it
5893up to that size.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame^]5894
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5895<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5896are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5897in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5898to the <tt>%hi</tt>th bit.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame^]5899
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5900<p>In reverse mode, a similar computation is made except that the bits are
5901reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5902<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame^]5903
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5904<h5>Examples:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame^]5905
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5906<pre>
5907 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
5908 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5909 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5910 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
5911 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
5912</pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame^]5913
5914</div>
5915
5916<!-- _______________________________________________________________________ -->
5917<div class="doc_subsubsection">
5918 <a name="int_sadd_ovf">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
5919</div>
5920
5921<div class="doc_text">
5922
5923<h5>Syntax:</h5>
5924
5925<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
5926on any integer bit width. However, not all targets support all bit widths.</p>
5927
5928<pre>
5929 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
5930 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
5931 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
5932</pre>
5933
5934<h5>Overview:</h5>
5935
5936<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
5937a signed addition of the two arguments, and indicate whether an overflow
5938occurred during the signed summation.</p>
5939
5940<h5>Arguments:</h5>
5941
5942<p>The arguments (%a and %b) and the first element of the result structure may
5943be of integer types of any bit width, but they must have the same bit width. The
5944second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
5945and <tt>%b</tt> are the two values that will undergo signed addition.</p>
5946
5947<h5>Semantics:</h5>
5948
5949<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
5950a signed addition of the two variables. They return a structure &mdash; the
5951first element of which is the signed summation, and the second element of which
5952is a bit specifying if the signed summation resulted in an overflow.</p>
5953
5954<h5>Examples:</h5>
5955<pre>
5956 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
5957 %sum = extractvalue {i32, i1} %res, 0
5958 %obit = extractvalue {i32, i1} %res, 1
5959 br i1 %obit, label %overflow, label %normal
5960</pre>
5961
5962</div>
5963
5964<!-- _______________________________________________________________________ -->
5965<div class="doc_subsubsection">
5966 <a name="int_uadd_ovf">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
5967</div>
5968
5969<div class="doc_text">
5970
5971<h5>Syntax:</h5>
5972
5973<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
5974on any integer bit width. However, not all targets support all bit widths.</p>
5975
5976<pre>
5977 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
5978 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
5979 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
5980</pre>
5981
5982<h5>Overview:</h5>
5983
5984<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
5985an unsigned addition of the two arguments, and indicate whether a carry occurred
5986during the unsigned summation.</p>
5987
5988<h5>Arguments:</h5>
5989
5990<p>The arguments (%a and %b) and the first element of the result structure may
5991be of integer types of any bit width, but they must have the same bit width. The
5992second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
5993and <tt>%b</tt> are the two values that will undergo unsigned addition.</p>
5994
5995<h5>Semantics:</h5>
5996
5997<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
5998an unsigned addition of the two arguments. They return a structure &mdash; the
5999first element of which is the sum, and the second element of which is a bit
6000specifying if the unsigned summation resulted in a carry.</p>
6001
6002<h5>Examples:</h5>
6003<pre>
6004 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6005 %sum = extractvalue {i32, i1} %res, 0
6006 %obit = extractvalue {i32, i1} %res, 1
6007 br i1 %obit, label %carry, label %normal
6008</pre>
6009
6010</div>
6011
6012<!-- _______________________________________________________________________ -->
6013<div class="doc_subsubsection">
6014 <a name="int_ssub_ovf">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
6015</div>
6016
6017<div class="doc_text">
6018
6019<h5>Syntax:</h5>
6020
6021<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
6022on any integer bit width. However, not all targets support all bit widths.</p>
6023
6024<pre>
6025 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6026 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6027 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6028</pre>
6029
6030<h5>Overview:</h5>
6031
6032<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6033a signed subtraction of the two arguments, and indicate whether an overflow
6034occurred during the signed subtraction.</p>
6035
6036<h5>Arguments:</h5>
6037
6038<p>The arguments (%a and %b) and the first element of the result structure may
6039be of integer types of any bit width, but they must have the same bit width. The
6040second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6041and <tt>%b</tt> are the two values that will undergo signed subtraction.</p>
6042
6043<h5>Semantics:</h5>
6044
6045<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6046a signed subtraction of the two arguments. They return a structure &mdash; the
6047first element of which is the subtraction, and the second element of which is a bit
6048specifying if the signed subtraction resulted in an overflow.</p>
6049
6050<h5>Examples:</h5>
6051<pre>
6052 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6053 %sum = extractvalue {i32, i1} %res, 0
6054 %obit = extractvalue {i32, i1} %res, 1
6055 br i1 %obit, label %overflow, label %normal
6056</pre>
6057
6058</div>
6059
6060<!-- _______________________________________________________________________ -->
6061<div class="doc_subsubsection">
6062 <a name="int_usub_ovf">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
6063</div>
6064
6065<div class="doc_text">
6066
6067<h5>Syntax:</h5>
6068
6069<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
6070on any integer bit width. However, not all targets support all bit widths.</p>
6071
6072<pre>
6073 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6074 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6075 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6076</pre>
6077
6078<h5>Overview:</h5>
6079
6080<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6081an unsigned subtraction of the two arguments, and indicate whether an overflow
6082occurred during the unsigned subtraction.</p>
6083
6084<h5>Arguments:</h5>
6085
6086<p>The arguments (%a and %b) and the first element of the result structure may
6087be of integer types of any bit width, but they must have the same bit width. The
6088second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6089and <tt>%b</tt> are the two values that will undergo unsigned subtraction.</p>
6090
6091<h5>Semantics:</h5>
6092
6093<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6094an unsigned subtraction of the two arguments. They return a structure &mdash; the
6095first element of which is the subtraction, and the second element of which is a bit
6096specifying if the unsigned subtraction resulted in an overflow.</p>
6097
6098<h5>Examples:</h5>
6099<pre>
6100 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6101 %sum = extractvalue {i32, i1} %res, 0
6102 %obit = extractvalue {i32, i1} %res, 1
6103 br i1 %obit, label %overflow, label %normal
6104</pre>
6105
6106</div>
6107
6108<!-- _______________________________________________________________________ -->
6109<div class="doc_subsubsection">
6110 <a name="int_smul_ovf">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
6111</div>
6112
6113<div class="doc_text">
6114
6115<h5>Syntax:</h5>
6116
6117<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
6118on any integer bit width. However, not all targets support all bit widths.</p>
6119
6120<pre>
6121 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6122 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6123 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6124</pre>
6125
6126<h5>Overview:</h5>
6127
6128<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6129a signed multiplication of the two arguments, and indicate whether an overflow
6130occurred during the signed multiplication.</p>
6131
6132<h5>Arguments:</h5>
6133
6134<p>The arguments (%a and %b) and the first element of the result structure may
6135be of integer types of any bit width, but they must have the same bit width. The
6136second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6137and <tt>%b</tt> are the two values that will undergo signed multiplication.</p>
6138
6139<h5>Semantics:</h5>
6140
6141<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6142a signed multiplication of the two arguments. They return a structure &mdash;
6143the first element of which is the multiplication, and the second element of
6144which is a bit specifying if the signed multiplication resulted in an
6145overflow.</p>
6146
6147<h5>Examples:</h5>
6148<pre>
6149 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6150 %sum = extractvalue {i32, i1} %res, 0
6151 %obit = extractvalue {i32, i1} %res, 1
6152 br i1 %obit, label %overflow, label %normal
6153</pre>
6154
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6155</div>
6156
6157<!-- ======================================================================= -->
6158<div class="doc_subsection">
6159 <a name="int_debugger">Debugger Intrinsics</a>
6160</div>
6161
6162<div class="doc_text">
6163<p>
6164The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
6165are described in the <a
6166href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
6167Debugging</a> document.
6168</p>
6169</div>
6170
6171
6172<!-- ======================================================================= -->
6173<div class="doc_subsection">
6174 <a name="int_eh">Exception Handling Intrinsics</a>
6175</div>
6176
6177<div class="doc_text">
6178<p> The LLVM exception handling intrinsics (which all start with
6179<tt>llvm.eh.</tt> prefix), are described in the <a
6180href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6181Handling</a> document. </p>
6182</div>
6183
6184<!-- ======================================================================= -->
6185<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6186 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6187</div>
6188
6189<div class="doc_text">
6190<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6191 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6192 the <tt>nest</tt> attribute, from a function. The result is a callable
6193 function pointer lacking the nest parameter - the caller does not need
6194 to provide a value for it. Instead, the value to use is stored in
6195 advance in a "trampoline", a block of memory usually allocated
6196 on the stack, which also contains code to splice the nest value into the
6197 argument list. This is used to implement the GCC nested function address
6198 extension.
6199</p>
6200<p>
6201 For example, if the function is
6202 <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]6203 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]6204<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6205 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6206 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6207 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6208 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6209</pre>
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]6210 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6211 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6212</div>
6213
6214<!-- _______________________________________________________________________ -->
6215<div class="doc_subsubsection">
6216 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6217</div>
6218<div class="doc_text">
6219<h5>Syntax:</h5>
6220<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6221declare 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]6222</pre>
6223<h5>Overview:</h5>
6224<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6225 This fills the memory pointed to by <tt>tramp</tt> with code
6226 and returns a function pointer suitable for executing it.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6227</p>
6228<h5>Arguments:</h5>
6229<p>
6230 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6231 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
6232 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sands35012212007-08-22 23:39:54 +0000[diff] [blame]6233 intrinsic. Note that the size and the alignment are target-specific - LLVM
6234 currently provides no portable way of determining them, so a front-end that
6235 generates this intrinsic needs to have some target-specific knowledge.
6236 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]6237</p>
6238<h5>Semantics:</h5>
6239<p>
6240 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6241 dependent code, turning it into a function. A pointer to this function is
6242 returned, but needs to be bitcast to an
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6243 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6244 before being called. The new function's signature is the same as that of
6245 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
6246 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
6247 of pointer type. Calling the new function is equivalent to calling
6248 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
6249 missing <tt>nest</tt> argument. If, after calling
6250 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
6251 modified, then the effect of any later call to the returned function pointer is
6252 undefined.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6253</p>
6254</div>
6255
6256<!-- ======================================================================= -->
6257<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6258 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6259</div>
6260
6261<div class="doc_text">
6262<p>
6263 These intrinsic functions expand the "universal IR" of LLVM to represent
6264 hardware constructs for atomic operations and memory synchronization. This
6265 provides an interface to the hardware, not an interface to the programmer. It
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]6266 is aimed at a low enough level to allow any programming models or APIs
6267 (Application Programming Interfaces) which
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6268 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
6269 hardware behavior. Just as hardware provides a "universal IR" for source
6270 languages, it also provides a starting point for developing a "universal"
6271 atomic operation and synchronization IR.
6272</p>
6273<p>
6274 These do <em>not</em> form an API such as high-level threading libraries,
6275 software transaction memory systems, atomic primitives, and intrinsic
6276 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6277 application libraries. The hardware interface provided by LLVM should allow
6278 a clean implementation of all of these APIs and parallel programming models.
6279 No one model or paradigm should be selected above others unless the hardware
6280 itself ubiquitously does so.
6281
6282</p>
6283</div>
6284
6285<!-- _______________________________________________________________________ -->
6286<div class="doc_subsubsection">
6287 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6288</div>
6289<div class="doc_text">
6290<h5>Syntax:</h5>
6291<pre>
6292declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
6293i1 &lt;device&gt; )
6294
6295</pre>
6296<h5>Overview:</h5>
6297<p>
6298 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6299 specific pairs of memory access types.
6300</p>
6301<h5>Arguments:</h5>
6302<p>
6303 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6304 The first four arguments enables a specific barrier as listed below. The fith
6305 argument specifies that the barrier applies to io or device or uncached memory.
6306
6307</p>
6308 <ul>
6309 <li><tt>ll</tt>: load-load barrier</li>
6310 <li><tt>ls</tt>: load-store barrier</li>
6311 <li><tt>sl</tt>: store-load barrier</li>
6312 <li><tt>ss</tt>: store-store barrier</li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6313 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6314 </ul>
6315<h5>Semantics:</h5>
6316<p>
6317 This intrinsic causes the system to enforce some ordering constraints upon
6318 the loads and stores of the program. This barrier does not indicate
6319 <em>when</em> any events will occur, it only enforces an <em>order</em> in
6320 which they occur. For any of the specified pairs of load and store operations
6321 (f.ex. load-load, or store-load), all of the first operations preceding the
6322 barrier will complete before any of the second operations succeeding the
6323 barrier begin. Specifically the semantics for each pairing is as follows:
6324</p>
6325 <ul>
6326 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6327 after the barrier begins.</li>
6328
6329 <li><tt>ls</tt>: All loads before the barrier must complete before any
6330 store after the barrier begins.</li>
6331 <li><tt>ss</tt>: All stores before the barrier must complete before any
6332 store after the barrier begins.</li>
6333 <li><tt>sl</tt>: All stores before the barrier must complete before any
6334 load after the barrier begins.</li>
6335 </ul>
6336<p>
6337 These semantics are applied with a logical "and" behavior when more than one
6338 is enabled in a single memory barrier intrinsic.
6339</p>
6340<p>
6341 Backends may implement stronger barriers than those requested when they do not
6342 support as fine grained a barrier as requested. Some architectures do not
6343 need all types of barriers and on such architectures, these become noops.
6344</p>
6345<h5>Example:</h5>
6346<pre>
6347%ptr = malloc i32
6348 store i32 4, %ptr
6349
6350%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6351 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6352 <i>; guarantee the above finishes</i>
6353 store i32 8, %ptr <i>; before this begins</i>
6354</pre>
6355</div>
6356
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6357<!-- _______________________________________________________________________ -->
6358<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6359 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6360</div>
6361<div class="doc_text">
6362<h5>Syntax:</h5>
6363<p>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6364 This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6365 any integer bit width and for different address spaces. Not all targets
6366 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6367
6368<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6369declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6370declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6371declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6372declare 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]6373
6374</pre>
6375<h5>Overview:</h5>
6376<p>
6377 This loads a value in memory and compares it to a given value. If they are
6378 equal, it stores a new value into the memory.
6379</p>
6380<h5>Arguments:</h5>
6381<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6382 The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6383 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6384 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6385 this integer type. While any bit width integer may be used, targets may only
6386 lower representations they support in hardware.
6387
6388</p>
6389<h5>Semantics:</h5>
6390<p>
6391 This entire intrinsic must be executed atomically. It first loads the value
6392 in memory pointed to by <tt>ptr</tt> and compares it with the value
6393 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
6394 loaded value is yielded in all cases. This provides the equivalent of an
6395 atomic compare-and-swap operation within the SSA framework.
6396</p>
6397<h5>Examples:</h5>
6398
6399<pre>
6400%ptr = malloc i32
6401 store i32 4, %ptr
6402
6403%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6404%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6405 <i>; yields {i32}:result1 = 4</i>
6406%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6407%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6408
6409%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6410%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6411 <i>; yields {i32}:result2 = 8</i>
6412%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6413
6414%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6415</pre>
6416</div>
6417
6418<!-- _______________________________________________________________________ -->
6419<div class="doc_subsubsection">
6420 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6421</div>
6422<div class="doc_text">
6423<h5>Syntax:</h5>
6424
6425<p>
6426 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6427 integer bit width. Not all targets support all bit widths however.</p>
6428<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6429declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6430declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6431declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6432declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6433
6434</pre>
6435<h5>Overview:</h5>
6436<p>
6437 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6438 the value from memory. It then stores the value in <tt>val</tt> in the memory
6439 at <tt>ptr</tt>.
6440</p>
6441<h5>Arguments:</h5>
6442
6443<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6444 The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6445 <tt>val</tt> argument and the result must be integers of the same bit width.
6446 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6447 integer type. The targets may only lower integer representations they
6448 support.
6449</p>
6450<h5>Semantics:</h5>
6451<p>
6452 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6453 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6454 equivalent of an atomic swap operation within the SSA framework.
6455
6456</p>
6457<h5>Examples:</h5>
6458<pre>
6459%ptr = malloc i32
6460 store i32 4, %ptr
6461
6462%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6463%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6464 <i>; yields {i32}:result1 = 4</i>
6465%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6466%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6467
6468%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6469%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6470 <i>; yields {i32}:result2 = 8</i>
6471
6472%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6473%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6474</pre>
6475</div>
6476
6477<!-- _______________________________________________________________________ -->
6478<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6479 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6480
6481</div>
6482<div class="doc_text">
6483<h5>Syntax:</h5>
6484<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6485 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]6486 integer bit width. Not all targets support all bit widths however.</p>
6487<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6488declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6489declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6490declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6491declare 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]6492
6493</pre>
6494<h5>Overview:</h5>
6495<p>
6496 This intrinsic adds <tt>delta</tt> to the value stored in memory at
6497 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6498</p>
6499<h5>Arguments:</h5>
6500<p>
6501
6502 The intrinsic takes two arguments, the first a pointer to an integer value
6503 and the second an integer value. The result is also an integer value. These
6504 integer types can have any bit width, but they must all have the same bit
6505 width. The targets may only lower integer representations they support.
6506</p>
6507<h5>Semantics:</h5>
6508<p>
6509 This intrinsic does a series of operations atomically. It first loads the
6510 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6511 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6512</p>
6513
6514<h5>Examples:</h5>
6515<pre>
6516%ptr = malloc i32
6517 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6518%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6519 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6520%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6521 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6522%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6523 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6524%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6525</pre>
6526</div>
6527
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6528<!-- _______________________________________________________________________ -->
6529<div class="doc_subsubsection">
6530 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6531
6532</div>
6533<div class="doc_text">
6534<h5>Syntax:</h5>
6535<p>
6536 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]6537 any integer bit width and for different address spaces. Not all targets
6538 support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6539<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6540declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6541declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6542declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6543declare 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]6544
6545</pre>
6546<h5>Overview:</h5>
6547<p>
6548 This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6549 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6550</p>
6551<h5>Arguments:</h5>
6552<p>
6553
6554 The intrinsic takes two arguments, the first a pointer to an integer value
6555 and the second an integer value. The result is also an integer value. These
6556 integer types can have any bit width, but they must all have the same bit
6557 width. The targets may only lower integer representations they support.
6558</p>
6559<h5>Semantics:</h5>
6560<p>
6561 This intrinsic does a series of operations atomically. It first loads the
6562 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6563 result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6564</p>
6565
6566<h5>Examples:</h5>
6567<pre>
6568%ptr = malloc i32
6569 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6570%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6571 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6572%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6573 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6574%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6575 <i>; yields {i32}:result3 = 2</i>
6576%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6577</pre>
6578</div>
6579
6580<!-- _______________________________________________________________________ -->
6581<div class="doc_subsubsection">
6582 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6583 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6584 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6585 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
6586
6587</div>
6588<div class="doc_text">
6589<h5>Syntax:</h5>
6590<p>
6591 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
6592 <tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6593 <tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
6594 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6595<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6596declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6597declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6598declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6599declare 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]6600
6601</pre>
6602
6603<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6604declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6605declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6606declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6607declare 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]6608
6609</pre>
6610
6611<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6612declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6613declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6614declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6615declare 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]6616
6617</pre>
6618
6619<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6620declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6621declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6622declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6623declare 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]6624
6625</pre>
6626<h5>Overview:</h5>
6627<p>
6628 These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6629 the value stored in memory at <tt>ptr</tt>. It yields the original value
6630 at <tt>ptr</tt>.
6631</p>
6632<h5>Arguments:</h5>
6633<p>
6634
6635 These intrinsics take two arguments, the first a pointer to an integer value
6636 and the second an integer value. The result is also an integer value. These
6637 integer types can have any bit width, but they must all have the same bit
6638 width. The targets may only lower integer representations they support.
6639</p>
6640<h5>Semantics:</h5>
6641<p>
6642 These intrinsics does a series of operations atomically. They first load the
6643 value stored at <tt>ptr</tt>. They then do the bitwise operation
6644 <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
6645 value stored at <tt>ptr</tt>.
6646</p>
6647
6648<h5>Examples:</h5>
6649<pre>
6650%ptr = malloc i32
6651 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6652%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6653 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6654%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6655 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6656%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6657 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6658%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6659 <i>; yields {i32}:result3 = FF</i>
6660%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6661</pre>
6662</div>
6663
6664
6665<!-- _______________________________________________________________________ -->
6666<div class="doc_subsubsection">
6667 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6668 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6669 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6670 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
6671
6672</div>
6673<div class="doc_text">
6674<h5>Syntax:</h5>
6675<p>
6676 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6677 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6678 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6679 address spaces. Not all targets
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6680 support all bit widths however.</p>
6681<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6682declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6683declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6684declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6685declare 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]6686
6687</pre>
6688
6689<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6690declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6691declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6692declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6693declare 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]6694
6695</pre>
6696
6697<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6698declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6699declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6700declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6701declare 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]6702
6703</pre>
6704
6705<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6706declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6707declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6708declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6709declare 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]6710
6711</pre>
6712<h5>Overview:</h5>
6713<p>
6714 These intrinsics takes the signed or unsigned minimum or maximum of
6715 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6716 original value at <tt>ptr</tt>.
6717</p>
6718<h5>Arguments:</h5>
6719<p>
6720
6721 These intrinsics take two arguments, the first a pointer to an integer value
6722 and the second an integer value. The result is also an integer value. These
6723 integer types can have any bit width, but they must all have the same bit
6724 width. The targets may only lower integer representations they support.
6725</p>
6726<h5>Semantics:</h5>
6727<p>
6728 These intrinsics does a series of operations atomically. They first load the
6729 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
6730 <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
6731 the original value stored at <tt>ptr</tt>.
6732</p>
6733
6734<h5>Examples:</h5>
6735<pre>
6736%ptr = malloc i32
6737 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6738%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6739 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6740%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6741 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6742%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6743 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6744%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6745 <i>; yields {i32}:result3 = 8</i>
6746%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6747</pre>
6748</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6749
6750<!-- ======================================================================= -->
6751<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6752 <a name="int_general">General Intrinsics</a>
6753</div>
6754
6755<div class="doc_text">
6756<p> This class of intrinsics is designed to be generic and has
6757no specific purpose. </p>
6758</div>
6759
6760<!-- _______________________________________________________________________ -->
6761<div class="doc_subsubsection">
6762 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6763</div>
6764
6765<div class="doc_text">
6766
6767<h5>Syntax:</h5>
6768<pre>
6769 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6770</pre>
6771
6772<h5>Overview:</h5>
6773
6774<p>
6775The '<tt>llvm.var.annotation</tt>' intrinsic
6776</p>
6777
6778<h5>Arguments:</h5>
6779
6780<p>
6781The first argument is a pointer to a value, the second is a pointer to a
6782global string, the third is a pointer to a global string which is the source
6783file name, and the last argument is the line number.
6784</p>
6785
6786<h5>Semantics:</h5>
6787
6788<p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6789This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6790This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6791annotations. These have no other defined use, they are ignored by code
6792generation and optimization.
6793</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6794</div>
6795
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6796<!-- _______________________________________________________________________ -->
6797<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]6798 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6799</div>
6800
6801<div class="doc_text">
6802
6803<h5>Syntax:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6804<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6805any integer bit width.
6806</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6807<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]6808 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6809 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6810 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6811 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6812 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]6813</pre>
6814
6815<h5>Overview:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6816
6817<p>
6818The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6819</p>
6820
6821<h5>Arguments:</h5>
6822
6823<p>
6824The first argument is an integer value (result of some expression),
6825the second is a pointer to a global string, the third is a pointer to a global
6826string which is the source file name, and the last argument is the line number.
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6827It returns the value of the first argument.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6828</p>
6829
6830<h5>Semantics:</h5>
6831
6832<p>
6833This intrinsic allows annotations to be put on arbitrary expressions
6834with arbitrary strings. This can be useful for special purpose optimizations
6835that want to look for these annotations. These have no other defined use, they
6836are ignored by code generation and optimization.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6837</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6838</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6839
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6840<!-- _______________________________________________________________________ -->
6841<div class="doc_subsubsection">
6842 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6843</div>
6844
6845<div class="doc_text">
6846
6847<h5>Syntax:</h5>
6848<pre>
6849 declare void @llvm.trap()
6850</pre>
6851
6852<h5>Overview:</h5>
6853
6854<p>
6855The '<tt>llvm.trap</tt>' intrinsic
6856</p>
6857
6858<h5>Arguments:</h5>
6859
6860<p>
6861None
6862</p>
6863
6864<h5>Semantics:</h5>
6865
6866<p>
6867This intrinsics is lowered to the target dependent trap instruction. If the
6868target does not have a trap instruction, this intrinsic will be lowered to the
6869call of the abort() function.
6870</p>
6871</div>
6872
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6873<!-- _______________________________________________________________________ -->
6874<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]6875 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6876</div>
6877<div class="doc_text">
6878<h5>Syntax:</h5>
6879<pre>
6880declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
6881
6882</pre>
6883<h5>Overview:</h5>
6884<p>
6885 The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and stores
6886 it onto the stack at <tt>slot</tt>. The stack slot is adjusted to ensure that
6887 it is placed on the stack before local variables.
6888</p>
6889<h5>Arguments:</h5>
6890<p>
6891 The <tt>llvm.stackprotector</tt> intrinsic requires two pointer arguments. The
6892 first argument is the value loaded from the stack guard
6893 <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt> that
6894 has enough space to hold the value of the guard.
6895</p>
6896<h5>Semantics:</h5>
6897<p>
6898 This intrinsic causes the prologue/epilogue inserter to force the position of
6899 the <tt>AllocaInst</tt> stack slot to be before local variables on the
6900 stack. This is to ensure that if a local variable on the stack is overwritten,
6901 it will destroy the value of the guard. When the function exits, the guard on
6902 the stack is checked against the original guard. If they're different, then
6903 the program aborts by calling the <tt>__stack_chk_fail()</tt> function.
6904</p>
6905</div>
6906
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6907<!-- *********************************************************************** -->
6908<hr>
6909<address>
6910 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]6911 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6912 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]6913 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6914
6915 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
6916 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
6917 Last modified: $Date$
6918</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]6919
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6920</body>
6921</html>