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gerrit-public.fairphone.software / toolchain / llvm-project / c792eb342ca1f1c89d508da9eb2ecc903bab1224 / . / llvm / docs / LangRef.html
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5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
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11</head>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
26 <li><a href="#functionstructure">Function Structure</a></li>
27 </ol>
28 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]29 <li><a href="#typesystem">Type System</a>
30 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]31 <li><a href="#t_primitive">Primitive Types</a>
32 <ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]33 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]34 </ol>
35 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]36 <li><a href="#t_derived">Derived Types</a>
37 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]38 <li><a href="#t_array">Array Type</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]39 <li><a href="#t_function">Function Type</a></li>
40 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]41 <li><a href="#t_struct">Structure Type</a></li>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]42 <li><a href="#t_packed">Packed Type</a></li>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]43 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]44 </ol>
45 </li>
46 </ol>
47 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]48 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]49 <ol>
50 <li><a href="#simpleconstants">Simple Constants</a>
51 <li><a href="#aggregateconstants">Aggregate Constants</a>
52 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
53 <li><a href="#undefvalues">Undefined Values</a>
54 <li><a href="#constantexprs">Constant Expressions</a>
55 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]56 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]57 <li><a href="#instref">Instruction Reference</a>
58 <ol>
59 <li><a href="#terminators">Terminator Instructions</a>
60 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]61 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
62 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]63 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
64 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]65 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]66 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]67 </ol>
68 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]69 <li><a href="#binaryops">Binary Operations</a>
70 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]71 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
72 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
73 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
74 <li><a href="#i_div">'<tt>div</tt>' Instruction</a></li>
75 <li><a href="#i_rem">'<tt>rem</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]76 <li><a href="#i_setcc">'<tt>set<i>cc</i></tt>' Instructions</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]77 </ol>
78 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]79 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
80 <ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]81 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]82 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]83 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
84 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
85 <li><a href="#i_shr">'<tt>shr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]86 </ol>
87 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]88 <li><a href="#memoryops">Memory Access Operations</a>
89 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]90 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
91 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
92 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
93 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
94 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
95 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
96 </ol>
97 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]98 <li><a href="#otherops">Other Operations</a>
99 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]100 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]101 <li><a href="#i_cast">'<tt>cast .. to</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]102 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]103 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]104 <li><a href="#i_vanext">'<tt>vanext</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]105 <li><a href="#i_vaarg">'<tt>vaarg</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]106 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]107 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]108 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]109 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]110 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]111 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]112 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
113 <ol>
114 <li><a href="#i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
115 <li><a href="#i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
116 <li><a href="#i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
117 </ol>
118 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]119 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
120 <ol>
121 <li><a href="#i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
122 <li><a href="#i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
123 <li><a href="#i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
124 </ol>
125 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]126 <li><a href="#int_codegen">Code Generator Intrinsics</a>
127 <ol>
128 <li><a href="#i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
129 <li><a href="#i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]130 <li><a href="#i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]131 <li><a href="#i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]132 </ol>
133 </li>
134 <li><a href="#int_os">Operating System Intrinsics</a>
135 <ol>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]136 <li><a href="#i_readport">'<tt>llvm.readport</tt>' Intrinsic</a></li>
137 <li><a href="#i_writeport">'<tt>llvm.writeport</tt>' Intrinsic</a></li>
John Criswella4501222004-04-12 15:02:16 +0000[diff] [blame]138 <li><a href="#i_readio">'<tt>llvm.readio</tt>' Intrinsic</a></li>
139 <li><a href="#i_writeio">'<tt>llvm.writeio</tt>' Intrinsic</a></li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]140 </ol>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]141 <li><a href="#int_libc">Standard C Library Intrinsics</a>
142 <ol>
143 <li><a href="#i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a></li>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]144 <li><a href="#i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a></li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]145 <li><a href="#i_memset">'<tt>llvm.memset</tt>' Intrinsic</a></li>
Alkis Evlogimenos9d740622004-06-12 19:19:14 +0000[diff] [blame]146 <li><a href="#i_isunordered">'<tt>llvm.isunordered</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]147 </ol>
148 </li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]149 <li><a href="#int_count">Bit counting Intrinsics</a>
150 <ol>
151 <li><a href="#int_ctpop">'<tt>llvm.ctpop</tt>' Intrinsic </a></li>
152 <li><a href="#int_cttz">'<tt>llvm.cttz</tt>' Intrinsic </a></li>
153 <li><a href="#int_ctlz">'<tt>llvm.ctlz</tt>' Intrinsic </a></li>
154 </ol>
155 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]156 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]157 </ol>
158 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]159</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]160
161<div class="doc_author">
162 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
163 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]164</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]165
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]166<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]167<div class="doc_section"> <a name="abstract">Abstract </a></div>
168<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]169
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]170<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]171<p>This document is a reference manual for the LLVM assembly language.
172LLVM is an SSA based representation that provides type safety,
173low-level operations, flexibility, and the capability of representing
174'all' high-level languages cleanly. It is the common code
175representation used throughout all phases of the LLVM compilation
176strategy.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]177</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]178
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]179<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]180<div class="doc_section"> <a name="introduction">Introduction</a> </div>
181<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]182
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]183<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]184
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]185<p>The LLVM code representation is designed to be used in three
186different forms: as an in-memory compiler IR, as an on-disk bytecode
187representation (suitable for fast loading by a Just-In-Time compiler),
188and as a human readable assembly language representation. This allows
189LLVM to provide a powerful intermediate representation for efficient
190compiler transformations and analysis, while providing a natural means
191to debug and visualize the transformations. The three different forms
192of LLVM are all equivalent. This document describes the human readable
193representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]194
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]195<p>The LLVM representation aims to be a light-weight and low-level
196while being expressive, typed, and extensible at the same time. It
197aims to be a "universal IR" of sorts, by being at a low enough level
198that high-level ideas may be cleanly mapped to it (similar to how
199microprocessors are "universal IR's", allowing many source languages to
200be mapped to them). By providing type information, LLVM can be used as
201the target of optimizations: for example, through pointer analysis, it
202can be proven that a C automatic variable is never accessed outside of
203the current function... allowing it to be promoted to a simple SSA
204value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]205
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]206</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]207
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]208<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]209<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]210
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]211<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]212
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]213<p>It is important to note that this document describes 'well formed'
214LLVM assembly language. There is a difference between what the parser
215accepts and what is considered 'well formed'. For example, the
216following instruction is syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]217
218<pre>
219 %x = <a href="#i_add">add</a> int 1, %x
220</pre>
221
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]222<p>...because the definition of <tt>%x</tt> does not dominate all of
223its uses. The LLVM infrastructure provides a verification pass that may
224be used to verify that an LLVM module is well formed. This pass is
225automatically run by the parser after parsing input assembly, and by
226the optimizer before it outputs bytecode. The violations pointed out
227by the verifier pass indicate bugs in transformation passes or input to
228the parser.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]229
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]230<!-- Describe the typesetting conventions here. --> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]231
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]232<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]233<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]234<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]235
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]236<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]237
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]238<p>LLVM uses three different forms of identifiers, for different
239purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]240
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]241<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]242 <li>Named values are represented as a string of characters with a '%' prefix.
243 For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
244 regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
245 Identifiers which require other characters in their names can be surrounded
246 with quotes. In this way, anything except a <tt>"</tt> character can be used
247 in a name.</li>
248
249 <li>Unnamed values are represented as an unsigned numeric value with a '%'
250 prefix. For example, %12, %2, %44.</li>
251
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]252 <li>Constants, which are described in a <a href="#constants">section about
253 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]254</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]255
256<p>LLVM requires that values start with a '%' sign for two reasons: Compilers
257don't need to worry about name clashes with reserved words, and the set of
258reserved words may be expanded in the future without penalty. Additionally,
259unnamed identifiers allow a compiler to quickly come up with a temporary
260variable without having to avoid symbol table conflicts.</p>
261
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]262<p>Reserved words in LLVM are very similar to reserved words in other
263languages. There are keywords for different opcodes ('<tt><a
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]264href="#i_add">add</a></tt>', '<tt><a href="#i_cast">cast</a></tt>', '<tt><a
265href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
266href="#t_void">void</a></tt>', '<tt><a href="#t_uint">uint</a></tt>', etc...),
267and others. These reserved words cannot conflict with variable names, because
268none of them start with a '%' character.</p>
269
270<p>Here is an example of LLVM code to multiply the integer variable
271'<tt>%X</tt>' by 8:</p>
272
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]273<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]274
275<pre>
276 %result = <a href="#i_mul">mul</a> uint %X, 8
277</pre>
278
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]279<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]280
281<pre>
282 %result = <a href="#i_shl">shl</a> uint %X, ubyte 3
283</pre>
284
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]285<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]286
287<pre>
288 <a href="#i_add">add</a> uint %X, %X <i>; yields {uint}:%0</i>
289 <a href="#i_add">add</a> uint %0, %0 <i>; yields {uint}:%1</i>
290 %result = <a href="#i_add">add</a> uint %1, %1
291</pre>
292
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]293<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
294important lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]295
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]296<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]297
298 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
299 line.</li>
300
301 <li>Unnamed temporaries are created when the result of a computation is not
302 assigned to a named value.</li>
303
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]304 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]305
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]306</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]307
308<p>...and it also show a convention that we follow in this document. When
309demonstrating instructions, we will follow an instruction with a comment that
310defines the type and name of value produced. Comments are shown in italic
311text.</p>
312
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]313</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]314
315<!-- *********************************************************************** -->
316<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
317<!-- *********************************************************************** -->
318
319<!-- ======================================================================= -->
320<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
321</div>
322
323<div class="doc_text">
324
325<p>LLVM programs are composed of "Module"s, each of which is a
326translation unit of the input programs. Each module consists of
327functions, global variables, and symbol table entries. Modules may be
328combined together with the LLVM linker, which merges function (and
329global variable) definitions, resolves forward declarations, and merges
330symbol table entries. Here is an example of the "hello world" module:</p>
331
332<pre><i>; Declare the string constant as a global constant...</i>
333<a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a
334 href="#globalvars">constant</a> <a href="#t_array">[13 x sbyte]</a> c"hello world\0A\00" <i>; [13 x sbyte]*</i>
335
336<i>; External declaration of the puts function</i>
337<a href="#functionstructure">declare</a> int %puts(sbyte*) <i>; int(sbyte*)* </i>
338
339<i>; Definition of main function</i>
340int %main() { <i>; int()* </i>
341 <i>; Convert [13x sbyte]* to sbyte *...</i>
342 %cast210 = <a
343 href="#i_getelementptr">getelementptr</a> [13 x sbyte]* %.LC0, long 0, long 0 <i>; sbyte*</i>
344
345 <i>; Call puts function to write out the string to stdout...</i>
346 <a
347 href="#i_call">call</a> int %puts(sbyte* %cast210) <i>; int</i>
348 <a
349 href="#i_ret">ret</a> int 0<br>}<br></pre>
350
351<p>This example is made up of a <a href="#globalvars">global variable</a>
352named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
353function, and a <a href="#functionstructure">function definition</a>
354for "<tt>main</tt>".</p>
355
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]356<p>In general, a module is made up of a list of global values,
357where both functions and global variables are global values. Global values are
358represented by a pointer to a memory location (in this case, a pointer to an
359array of char, and a pointer to a function), and have one of the following <a
360href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]361
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]362</div>
363
364<!-- ======================================================================= -->
365<div class="doc_subsection">
366 <a name="linkage">Linkage Types</a>
367</div>
368
369<div class="doc_text">
370
371<p>
372All Global Variables and Functions have one of the following types of linkage:
373</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]374
375<dl>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]376
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]377 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]378
379 <dd>Global values with internal linkage are only directly accessible by
380 objects in the current module. In particular, linking code into a module with
381 an internal global value may cause the internal to be renamed as necessary to
382 avoid collisions. Because the symbol is internal to the module, all
383 references can be updated. This corresponds to the notion of the
384 '<tt>static</tt>' keyword in C, or the idea of "anonymous namespaces" in C++.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]385 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]386
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]387 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]388
389 <dd>"<tt>linkonce</tt>" linkage is similar to <tt>internal</tt> linkage, with
390 the twist that linking together two modules defining the same
391 <tt>linkonce</tt> globals will cause one of the globals to be discarded. This
392 is typically used to implement inline functions. Unreferenced
393 <tt>linkonce</tt> globals are allowed to be discarded.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]394 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]395
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]396 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]397
398 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
399 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
400 used to implement constructs in C such as "<tt>int X;</tt>" at global scope.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]401 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]402
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]403 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]404
405 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
406 pointer to array type. When two global variables with appending linkage are
407 linked together, the two global arrays are appended together. This is the
408 LLVM, typesafe, equivalent of having the system linker append together
409 "sections" with identical names when .o files are linked.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]410 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]411
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]412 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]413
414 <dd>If none of the above identifiers are used, the global is externally
415 visible, meaning that it participates in linkage and can be used to resolve
416 external symbol references.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]417 </dd>
418</dl>
419
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]420<p><a name="linkage_external">For example, since the "<tt>.LC0</tt>"
421variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
422variable and was linked with this one, one of the two would be renamed,
423preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
424external (i.e., lacking any linkage declarations), they are accessible
425outside of the current module. It is illegal for a function <i>declaration</i>
426to have any linkage type other than "externally visible".</a></p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]427
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]428</div>
429
430<!-- ======================================================================= -->
431<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]432 <a name="callingconv">Calling Conventions</a>
433</div>
434
435<div class="doc_text">
436
437<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
438and <a href="#i_invoke">invokes</a> can all have an optional calling convention
439specified for the call. The calling convention of any pair of dynamic
440caller/callee must match, or the behavior of the program is undefined. The
441following calling conventions are supported by LLVM, and more may be added in
442the future:</p>
443
444<dl>
445 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
446
447 <dd>This calling convention (the default if no other calling convention is
448 specified) matches the target C calling conventions. This calling convention
449 supports varargs function calls, and tolerates some mismatch in the declared
450 prototype and implemented declaration of the function (as does normal C).
451 </dd>
452
453 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
454
455 <dd>This calling convention attempts to make calls as fast as possible
456 (e.g. by passing things in registers). This calling convention allows the
457 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattnerc792eb32005-05-06 23:08:23 +0000[diff] [blame^]458 without having to conform to an externally specified ABI. Implementations of
459 this convention should allow arbitrary tail call optimization to be supported.
460 This calling convention does not support varargs and requires the prototype of
461 all callees to exactly match the prototype of the function definition.
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]462 </dd>
463
464 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
465
466 <dd>This calling convention attempts to make code in the caller as efficient
467 as possible under the assumption that the call is not commonly executed. As
468 such, these calls often preserve all registers so that the call does not break
469 any live ranges in the caller side. This calling convention does not support
470 varargs and requires the prototype of all callees to exactly match the
471 prototype of the function definition.
472 </dd>
473
474 <dt><b>"<tt>cc &lt;<it>n</it>&gt;</tt>" - Numbered convention</b>:</dt>
475
476 <dd>Any calling convention may be specified by number, allowing
477 target-specific calling conventions to be used. Target specific calling
478 conventions start at 64.
479 </dd>
480
481<p>More calling conventions can be added/defined on an as-needed basis, to
482support pascal conventions or any other well-known target-independent
483convention.</p>
484
485</div>
486
487<!-- ======================================================================= -->
488<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]489 <a name="globalvars">Global Variables</a>
490</div>
491
492<div class="doc_text">
493
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]494<p>Global variables define regions of memory allocated at compilation time
495instead of run-time. Global variables may optionally be initialized. A
496variable may be defined as a global "constant", which indicates that the
497contents of the variable will <b>never</b> be modified (enabling better
498optimization, allowing the global data to be placed in the read-only section of
499an executable, etc). Note that variables that need runtime initialization
500cannot be marked "constant", as there is a store to the variable.</p>
501
502<p>
503LLVM explicitly allows <em>declarations</em> of global variables to be marked
504constant, even if the final definition of the global is not. This capability
505can be used to enable slightly better optimization of the program, but requires
506the language definition to guarantee that optimizations based on the
507'constantness' are valid for the translation units that do not include the
508definition.
509</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]510
511<p>As SSA values, global variables define pointer values that are in
512scope (i.e. they dominate) all basic blocks in the program. Global
513variables always define a pointer to their "content" type because they
514describe a region of memory, and all memory objects in LLVM are
515accessed through pointers.</p>
516
517</div>
518
519
520<!-- ======================================================================= -->
521<div class="doc_subsection">
522 <a name="functionstructure">Functions</a>
523</div>
524
525<div class="doc_text">
526
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]527<p>LLVM function definitions consist of an optional <a href="#linkage">linkage
528type</a>, an optional <a href="#callingconv">calling convention</a>, a return
529type, a function name, a (possibly empty) argument list, an opening curly brace,
530a list of basic blocks, and a closing curly brace. LLVM function declarations
531are defined with the "<tt>declare</tt>" keyword, an optional <a
532href="#callingconv">calling convention</a>, a return type, a function name, and
533a possibly empty list of arguments.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]534
535<p>A function definition contains a list of basic blocks, forming the CFG for
536the function. Each basic block may optionally start with a label (giving the
537basic block a symbol table entry), contains a list of instructions, and ends
538with a <a href="#terminators">terminator</a> instruction (such as a branch or
539function return).</p>
540
541<p>The first basic block in program is special in two ways: it is immediately
542executed on entrance to the function, and it is not allowed to have predecessor
543basic blocks (i.e. there can not be any branches to the entry block of a
544function). Because the block can have no predecessors, it also cannot have any
545<a href="#i_phi">PHI nodes</a>.</p>
546
547<p>LLVM functions are identified by their name and type signature. Hence, two
548functions with the same name but different parameter lists or return values are
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]549considered different functions, and LLVM will resolve references to each
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]550appropriately.</p>
551
552</div>
553
554
555
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]556<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]557<div class="doc_section"> <a name="typesystem">Type System</a> </div>
558<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]559
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]560<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]561
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]562<p>The LLVM type system is one of the most important features of the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]563intermediate representation. Being typed enables a number of
564optimizations to be performed on the IR directly, without having to do
565extra analyses on the side before the transformation. A strong type
566system makes it easier to read the generated code and enables novel
567analyses and transformations that are not feasible to perform on normal
568three address code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]569
570</div>
571
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]572<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]573<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]574<div class="doc_text">
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]575<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]576system. The current set of primitive types is as follows:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]577
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]578<table class="layout">
579 <tr class="layout">
580 <td class="left">
581 <table>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]582 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]583 <tr><th>Type</th><th>Description</th></tr>
584 <tr><td><tt>void</tt></td><td>No value</td></tr>
Misha Brukman36c6bc12005-04-22 18:02:52 +0000[diff] [blame]585 <tr><td><tt>ubyte</tt></td><td>Unsigned 8-bit value</td></tr>
586 <tr><td><tt>ushort</tt></td><td>Unsigned 16-bit value</td></tr>
587 <tr><td><tt>uint</tt></td><td>Unsigned 32-bit value</td></tr>
588 <tr><td><tt>ulong</tt></td><td>Unsigned 64-bit value</td></tr>
589 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]590 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]591 </tbody>
592 </table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]593 </td>
594 <td class="right">
595 <table>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]596 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]597 <tr><th>Type</th><th>Description</th></tr>
598 <tr><td><tt>bool</tt></td><td>True or False value</td></tr>
Misha Brukman36c6bc12005-04-22 18:02:52 +0000[diff] [blame]599 <tr><td><tt>sbyte</tt></td><td>Signed 8-bit value</td></tr>
600 <tr><td><tt>short</tt></td><td>Signed 16-bit value</td></tr>
601 <tr><td><tt>int</tt></td><td>Signed 32-bit value</td></tr>
602 <tr><td><tt>long</tt></td><td>Signed 64-bit value</td></tr>
603 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]604 </tbody>
605 </table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]606 </td>
607 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]608</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]609</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]610
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]611<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]612<div class="doc_subsubsection"> <a name="t_classifications">Type
613Classifications</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]614<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]615<p>These different primitive types fall into a few useful
616classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]617
618<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]619 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]620 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]621 <tr>
622 <td><a name="t_signed">signed</a></td>
623 <td><tt>sbyte, short, int, long, float, double</tt></td>
624 </tr>
625 <tr>
626 <td><a name="t_unsigned">unsigned</a></td>
627 <td><tt>ubyte, ushort, uint, ulong</tt></td>
628 </tr>
629 <tr>
630 <td><a name="t_integer">integer</a></td>
631 <td><tt>ubyte, sbyte, ushort, short, uint, int, ulong, long</tt></td>
632 </tr>
633 <tr>
634 <td><a name="t_integral">integral</a></td>
Misha Brukman20f9a622004-08-12 20:16:08 +0000[diff] [blame]635 <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long</tt>
636 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]637 </tr>
638 <tr>
639 <td><a name="t_floating">floating point</a></td>
640 <td><tt>float, double</tt></td>
641 </tr>
642 <tr>
643 <td><a name="t_firstclass">first class</a></td>
Misha Brukman20f9a622004-08-12 20:16:08 +0000[diff] [blame]644 <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long,<br>
645 float, double, <a href="#t_pointer">pointer</a>,
646 <a href="#t_packed">packed</a></tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]647 </tr>
648 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]649</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]650
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]651<p>The <a href="#t_firstclass">first class</a> types are perhaps the
652most important. Values of these types are the only ones which can be
653produced by instructions, passed as arguments, or used as operands to
654instructions. This means that all structures and arrays must be
655manipulated either by pointer or by component.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]656</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]657
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]658<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]659<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]660
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]661<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]662
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]663<p>The real power in LLVM comes from the derived types in the system.
664This is what allows a programmer to represent arrays, functions,
665pointers, and other useful types. Note that these derived types may be
666recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]667
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]668</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]669
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]670<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]671<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]672
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]673<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]674
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]675<h5>Overview:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]676
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]677<p>The array type is a very simple derived type that arranges elements
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]678sequentially in memory. The array type requires a size (number of
679elements) and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]680
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]681<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]682
683<pre>
684 [&lt;# elements&gt; x &lt;elementtype&gt;]
685</pre>
686
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]687<p>The number of elements is a constant integer value, elementtype may
688be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]689
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]690<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]691<table class="layout">
692 <tr class="layout">
693 <td class="left">
694 <tt>[40 x int ]</tt><br/>
695 <tt>[41 x int ]</tt><br/>
696 <tt>[40 x uint]</tt><br/>
697 </td>
698 <td class="left">
699 Array of 40 integer values.<br/>
700 Array of 41 integer values.<br/>
701 Array of 40 unsigned integer values.<br/>
702 </td>
703 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]704</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]705<p>Here are some examples of multidimensional arrays:</p>
706<table class="layout">
707 <tr class="layout">
708 <td class="left">
709 <tt>[3 x [4 x int]]</tt><br/>
710 <tt>[12 x [10 x float]]</tt><br/>
711 <tt>[2 x [3 x [4 x uint]]]</tt><br/>
712 </td>
713 <td class="left">
714 3x4 array integer values.<br/>
715 12x10 array of single precision floating point values.<br/>
716 2x3x4 array of unsigned integer values.<br/>
717 </td>
718 </tr>
719</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]720</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]721
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]722<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]723<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]724<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]725<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]726<p>The function type can be thought of as a function signature. It
727consists of a return type and a list of formal parameter types.
John Criswella0d50d22003-11-25 21:45:46 +0000[diff] [blame]728Function types are usually used to build virtual function tables
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]729(which are structures of pointers to functions), for indirect function
730calls, and when defining a function.</p>
John Criswella0d50d22003-11-25 21:45:46 +0000[diff] [blame]731<p>
732The return type of a function type cannot be an aggregate type.
733</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]734<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]735<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
Misha Brukman20f9a622004-08-12 20:16:08 +0000[diff] [blame]736<p>Where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
737specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]738which indicates that the function takes a variable number of arguments.
739Variable argument functions can access their arguments with the <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]740 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]741<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]742<table class="layout">
743 <tr class="layout">
744 <td class="left">
745 <tt>int (int)</tt> <br/>
746 <tt>float (int, int *) *</tt><br/>
747 <tt>int (sbyte *, ...)</tt><br/>
748 </td>
749 <td class="left">
750 function taking an <tt>int</tt>, returning an <tt>int</tt><br/>
751 <a href="#t_pointer">Pointer</a> to a function that takes an
Misha Brukman20f9a622004-08-12 20:16:08 +0000[diff] [blame]752 <tt>int</tt> and a <a href="#t_pointer">pointer</a> to <tt>int</tt>,
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]753 returning <tt>float</tt>.<br/>
754 A vararg function that takes at least one <a href="#t_pointer">pointer</a>
755 to <tt>sbyte</tt> (signed char in C), which returns an integer. This is
756 the signature for <tt>printf</tt> in LLVM.<br/>
757 </td>
758 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]759</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]760
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]761</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]762<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]763<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]764<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]765<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]766<p>The structure type is used to represent a collection of data members
767together in memory. The packing of the field types is defined to match
768the ABI of the underlying processor. The elements of a structure may
769be any type that has a size.</p>
770<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
771and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
772field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
773instruction.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]774<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]775<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]776<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]777<table class="layout">
778 <tr class="layout">
779 <td class="left">
780 <tt>{ int, int, int }</tt><br/>
781 <tt>{ float, int (int) * }</tt><br/>
782 </td>
783 <td class="left">
784 a triple of three <tt>int</tt> values<br/>
785 A pair, where the first element is a <tt>float</tt> and the second element
786 is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a>
787 that takes an <tt>int</tt>, returning an <tt>int</tt>.<br/>
788 </td>
789 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]790</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]791</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]792
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]793<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]794<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]795<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]796<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]797<p>As in many languages, the pointer type represents a pointer or
798reference to another object, which must live in memory.</p>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]799<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]800<pre> &lt;type&gt; *<br></pre>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]801<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]802<table class="layout">
803 <tr class="layout">
804 <td class="left">
805 <tt>[4x int]*</tt><br/>
806 <tt>int (int *) *</tt><br/>
807 </td>
808 <td class="left">
809 A <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of
810 four <tt>int</tt> values<br/>
811 A <a href="#t_pointer">pointer</a> to a <a
Chris Lattner16fb0032005-02-19 02:22:14 +0000[diff] [blame]812 href="#t_function">function</a> that takes an <tt>int*</tt>, returning an
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]813 <tt>int</tt>.<br/>
814 </td>
815 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]816</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]817</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]818
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]819<!-- _______________________________________________________________________ -->
820<div class="doc_subsubsection"> <a name="t_packed">Packed Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]821<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]822
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]823<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]824
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]825<p>A packed type is a simple derived type that represents a vector
826of elements. Packed types are used when multiple primitive data
827are operated in parallel using a single instruction (SIMD).
828A packed type requires a size (number of
829elements) and an underlying primitive data type. Packed types are
830considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]831
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]832<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]833
834<pre>
835 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
836</pre>
837
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]838<p>The number of elements is a constant integer value, elementtype may
839be any integral or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]840
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]841<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]842
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]843<table class="layout">
844 <tr class="layout">
845 <td class="left">
846 <tt>&lt;4 x int&gt;</tt><br/>
847 <tt>&lt;8 x float&gt;</tt><br/>
848 <tt>&lt;2 x uint&gt;</tt><br/>
849 </td>
850 <td class="left">
851 Packed vector of 4 integer values.<br/>
852 Packed vector of 8 floating-point values.<br/>
853 Packed vector of 2 unsigned integer values.<br/>
854 </td>
855 </tr>
856</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]857</div>
858
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]859<!-- _______________________________________________________________________ -->
860<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
861<div class="doc_text">
862
863<h5>Overview:</h5>
864
865<p>Opaque types are used to represent unknown types in the system. This
866corresponds (for example) to the C notion of a foward declared structure type.
867In LLVM, opaque types can eventually be resolved to any type (not just a
868structure type).</p>
869
870<h5>Syntax:</h5>
871
872<pre>
873 opaque
874</pre>
875
876<h5>Examples:</h5>
877
878<table class="layout">
879 <tr class="layout">
880 <td class="left">
881 <tt>opaque</tt>
882 </td>
883 <td class="left">
884 An opaque type.<br/>
885 </td>
886 </tr>
887</table>
888</div>
889
890
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]891<!-- *********************************************************************** -->
892<div class="doc_section"> <a name="constants">Constants</a> </div>
893<!-- *********************************************************************** -->
894
895<div class="doc_text">
896
897<p>LLVM has several different basic types of constants. This section describes
898them all and their syntax.</p>
899
900</div>
901
902<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]903<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]904
905<div class="doc_text">
906
907<dl>
908 <dt><b>Boolean constants</b></dt>
909
910 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
911 constants of the <tt><a href="#t_primitive">bool</a></tt> type.
912 </dd>
913
914 <dt><b>Integer constants</b></dt>
915
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]916 <dd>Standard integers (such as '4') are constants of the <a
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]917 href="#t_integer">integer</a> type. Negative numbers may be used with signed
918 integer types.
919 </dd>
920
921 <dt><b>Floating point constants</b></dt>
922
923 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
924 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]925 notation. Floating point constants have an optional hexadecimal
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]926 notation (see below). Floating point constants must have a <a
927 href="#t_floating">floating point</a> type. </dd>
928
929 <dt><b>Null pointer constants</b></dt>
930
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]931 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]932 and must be of <a href="#t_pointer">pointer type</a>.</dd>
933
934</dl>
935
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]936<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]937of floating point constants. For example, the form '<tt>double
9380x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
9394.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]940(and the only time that they are generated by the disassembler) is when a
941floating point constant must be emitted but it cannot be represented as a
942decimal floating point number. For example, NaN's, infinities, and other
943special values are represented in their IEEE hexadecimal format so that
944assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]945
946</div>
947
948<!-- ======================================================================= -->
949<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
950</div>
951
952<div class="doc_text">
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]953<p>Aggregate constants arise from aggregation of simple constants
954and smaller aggregate constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]955
956<dl>
957 <dt><b>Structure constants</b></dt>
958
959 <dd>Structure constants are represented with notation similar to structure
960 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]961 (<tt>{}</tt>)). For example: "<tt>{ int 4, float 17.0, int* %G }</tt>",
962 where "<tt>%G</tt>" is declared as "<tt>%G = external global int</tt>". Structure constants
963 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]964 types of elements must match those specified by the type.
965 </dd>
966
967 <dt><b>Array constants</b></dt>
968
969 <dd>Array constants are represented with notation similar to array type
970 definitions (a comma separated list of elements, surrounded by square brackets
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]971 (<tt>[]</tt>)). For example: "<tt>[ int 42, int 11, int 74 ]</tt>". Array
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]972 constants must have <a href="#t_array">array type</a>, and the number and
973 types of elements must match those specified by the type.
974 </dd>
975
976 <dt><b>Packed constants</b></dt>
977
978 <dd>Packed constants are represented with notation similar to packed type
979 definitions (a comma separated list of elements, surrounded by
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]980 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; int 42,
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]981 int 11, int 74, int 100 &gt;</tt>". Packed constants must have <a
982 href="#t_packed">packed type</a>, and the number and types of elements must
983 match those specified by the type.
984 </dd>
985
986 <dt><b>Zero initialization</b></dt>
987
988 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
989 value to zero of <em>any</em> type, including scalar and aggregate types.
990 This is often used to avoid having to print large zero initializers (e.g. for
991 large arrays), and is always exactly equivalent to using explicit zero
992 initializers.
993 </dd>
994</dl>
995
996</div>
997
998<!-- ======================================================================= -->
999<div class="doc_subsection">
1000 <a name="globalconstants">Global Variable and Function Addresses</a>
1001</div>
1002
1003<div class="doc_text">
1004
1005<p>The addresses of <a href="#globalvars">global variables</a> and <a
1006href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1007constants. These constants are explicitly referenced when the <a
1008href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1009href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1010file:</p>
1011
1012<pre>
1013 %X = global int 17
1014 %Y = global int 42
1015 %Z = global [2 x int*] [ int* %X, int* %Y ]
1016</pre>
1017
1018</div>
1019
1020<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1021<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1022<div class="doc_text">
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1023 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
1024 no specific value. Undefined values may be of any type, and be used anywhere
1025 a constant is permitted.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1026
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1027 <p>Undefined values indicate to the compiler that the program is well defined
1028 no matter what value is used, giving the compiler more freedom to optimize.
1029 </p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1030</div>
1031
1032<!-- ======================================================================= -->
1033<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1034</div>
1035
1036<div class="doc_text">
1037
1038<p>Constant expressions are used to allow expressions involving other constants
1039to be used as constants. Constant expressions may be of any <a
1040href="#t_firstclass">first class</a> type, and may involve any LLVM operation
1041that does not have side effects (e.g. load and call are not supported). The
1042following is the syntax for constant expressions:</p>
1043
1044<dl>
1045 <dt><b><tt>cast ( CST to TYPE )</tt></b></dt>
1046
1047 <dd>Cast a constant to another type.</dd>
1048
1049 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1050
1051 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1052 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1053 instruction, the index list may have zero or more indexes, which are required
1054 to make sense for the type of "CSTPTR".</dd>
1055
1056 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1057
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1058 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1059 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1060 binary</a> operations. The constraints on operands are the same as those for
1061 the corresponding instruction (e.g. no bitwise operations on floating point
1062 are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1063</dl>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1064</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]1065
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1066<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1067<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1068<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1069
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1070<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1071
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1072<p>The LLVM instruction set consists of several different
1073classifications of instructions: <a href="#terminators">terminator
1074instructions</a>, <a href="#binaryops">binary instructions</a>, <a
1075 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1076instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1077
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1078</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1079
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1080<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1081<div class="doc_subsection"> <a name="terminators">Terminator
1082Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1083
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1084<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1085
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1086<p>As mentioned <a href="#functionstructure">previously</a>, every
1087basic block in a program ends with a "Terminator" instruction, which
1088indicates which block should be executed after the current block is
1089finished. These terminator instructions typically yield a '<tt>void</tt>'
1090value: they produce control flow, not values (the one exception being
1091the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1092<p>There are six different terminator instructions: the '<a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1093 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1094instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1095the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1096 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1097 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1098
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1099</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1100
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1101<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1102<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1103Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1104<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1105<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1106<pre> ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1107 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1108</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1109<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1110<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
1111value) from a function, back to the caller.</p>
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]1112<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1113returns a value and then causes control flow, and one that just causes
1114control flow to occur.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1115<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1116<p>The '<tt>ret</tt>' instruction may return any '<a
1117 href="#t_firstclass">first class</a>' type. Notice that a function is
1118not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1119instruction inside of the function that returns a value that does not
1120match the return type of the function.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1121<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1122<p>When the '<tt>ret</tt>' instruction is executed, control flow
1123returns back to the calling function's context. If the caller is a "<a
John Criswell40db33f2004-06-25 15:16:57 +0000[diff] [blame]1124 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1125the instruction after the call. If the caller was an "<a
1126 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
1127at the beginning "normal" of the destination block. If the instruction
1128returns a value, that value shall set the call or invoke instruction's
1129return value.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1130<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1131<pre> ret int 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1132 ret void <i>; Return from a void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1133</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1134</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1135<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1136<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1137<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1138<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1139<pre> br bool &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1140</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1141<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1142<p>The '<tt>br</tt>' instruction is used to cause control flow to
1143transfer to a different basic block in the current function. There are
1144two forms of this instruction, corresponding to a conditional branch
1145and an unconditional branch.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1146<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1147<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
1148single '<tt>bool</tt>' value and two '<tt>label</tt>' values. The
1149unconditional form of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>'
1150value as a target.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1151<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1152<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>bool</tt>'
1153argument is evaluated. If the value is <tt>true</tt>, control flows
1154to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1155control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1156<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1157<pre>Test:<br> %cond = <a href="#i_setcc">seteq</a> int %a, %b<br> br bool %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
1158 href="#i_ret">ret</a> int 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> int 0<br></pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1159</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1160<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1161<div class="doc_subsubsection">
1162 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1163</div>
1164
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1165<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1166<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1167
1168<pre>
1169 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1170</pre>
1171
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1172<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1173
1174<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1175several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1176instruction, allowing a branch to occur to one of many possible
1177destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1178
1179
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1180<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1181
1182<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1183comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1184an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1185table is not allowed to contain duplicate constant entries.</p>
1186
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1187<h5>Semantics:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1188
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1189<p>The <tt>switch</tt> instruction specifies a table of values and
1190destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1191table is searched for the given value. If the value is found, control flow is
1192transfered to the corresponding destination; otherwise, control flow is
1193transfered to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1194
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1195<h5>Implementation:</h5>
1196
1197<p>Depending on properties of the target machine and the particular
1198<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1199ways. For example, it could be generated as a series of chained conditional
1200branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1201
1202<h5>Example:</h5>
1203
1204<pre>
1205 <i>; Emulate a conditional br instruction</i>
1206 %Val = <a href="#i_cast">cast</a> bool %value to int
1207 switch int %Val, label %truedest [int 0, label %falsedest ]
1208
1209 <i>; Emulate an unconditional br instruction</i>
1210 switch uint 0, label %dest [ ]
1211
1212 <i>; Implement a jump table:</i>
1213 switch uint %val, label %otherwise [ uint 0, label %onzero
1214 uint 1, label %onone
1215 uint 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1216</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1217</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1218
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1219<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1220<div class="doc_subsubsection">
1221 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1222</div>
1223
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1224<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1225
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1226<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1227
1228<pre>
1229 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] &lt;ptr to function ty&gt; %&lt;function ptr val&gt;(&lt;function args&gt;)
1230 to label &lt;normal label&gt; except label &lt;exception label&gt;
1231</pre>
1232
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]1233<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1234
1235<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1236function, with the possibility of control flow transfer to either the
1237'<tt>normal</tt>' <tt>label</tt> label or the
1238'<tt>exception</tt>'<tt>label</tt>. If the callee function returns with the
1239"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1240"normal" label. If the callee (or any indirect callees) returns with the "<a
1241href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted, and
1242continued at the dynamically nearest "except" label.</p>
1243
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1244<h5>Arguments:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1245
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1246<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1247
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1248<ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1249 <li>
1250 <p>The optional "cconv" marker indicates which <a href="callingconv">calling
1251 convention</a> the call should use. If none is specified, the call defaults
1252 to using C calling conventions.
1253 </li>
1254 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1255 function value being invoked. In most cases, this is a direct function
1256 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1257 an arbitrary pointer to function value.
1258 </li>
1259
1260 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1261 function to be invoked. </li>
1262
1263 <li>'<tt>function args</tt>': argument list whose types match the function
1264 signature argument types. If the function signature indicates the function
1265 accepts a variable number of arguments, the extra arguments can be
1266 specified. </li>
1267
1268 <li>'<tt>normal label</tt>': the label reached when the called function
1269 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1270
1271 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1272 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1273
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1274</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1275
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1276<h5>Semantics:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1277
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1278<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1279href="#i_call">call</a></tt>' instruction in most regards. The primary
1280difference is that it establishes an association with a label, which is used by
1281the runtime library to unwind the stack.</p>
1282
1283<p>This instruction is used in languages with destructors to ensure that proper
1284cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1285exception. Additionally, this is important for implementation of
1286'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1287
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1288<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1289<pre>
1290 %retval = invoke int %Test(int 15) to label %Continue
1291 except label %TestCleanup <i>; {int}:retval set</i>
1292 %retval = invoke <a href="#callingconv">coldcc</a> int %Test(int 15) to label %Continue
1293 except label %TestCleanup <i>; {int}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1294</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1295</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1296
1297
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1298<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1299
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1300<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1301Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1302
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1303<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1304
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1305<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1306<pre>
1307 unwind
1308</pre>
1309
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1310<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1311
1312<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1313at the first callee in the dynamic call stack which used an <a
1314href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1315primarily used to implement exception handling.</p>
1316
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1317<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1318
1319<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1320immediately halt. The dynamic call stack is then searched for the first <a
1321href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1322execution continues at the "exceptional" destination block specified by the
1323<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1324dynamic call chain, undefined behavior results.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1325</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1326
1327<!-- _______________________________________________________________________ -->
1328
1329<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1330Instruction</a> </div>
1331
1332<div class="doc_text">
1333
1334<h5>Syntax:</h5>
1335<pre>
1336 unreachable
1337</pre>
1338
1339<h5>Overview:</h5>
1340
1341<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1342instruction is used to inform the optimizer that a particular portion of the
1343code is not reachable. This can be used to indicate that the code after a
1344no-return function cannot be reached, and other facts.</p>
1345
1346<h5>Semantics:</h5>
1347
1348<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1349</div>
1350
1351
1352
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1353<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1354<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1355<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1356<p>Binary operators are used to do most of the computation in a
1357program. They require two operands, execute an operation on them, and
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1358produce a single value. The operands might represent
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1359multiple data, as is the case with the <a href="#t_packed">packed</a> data type.
1360The result value of a binary operator is not
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1361necessarily the same type as its operands.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1362<p>There are several different binary operators:</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1363</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1364<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1365<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1366Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1367<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1368<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1369<pre> &lt;result&gt; = add &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1370</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1371<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1372<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1373<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1374<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1375 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
1376 This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1377Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1378<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1379<p>The value produced is the integer or floating point sum of the two
1380operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1381<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1382<pre> &lt;result&gt; = add int 4, %var <i>; yields {int}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1383</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1384</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1385<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1386<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1387Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1388<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1389<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1390<pre> &lt;result&gt; = sub &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1391</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1392<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1393<p>The '<tt>sub</tt>' instruction returns the difference of its two
1394operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1395<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1396instruction present in most other intermediate representations.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1397<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1398<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1399 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1400values.
1401This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1402Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1403<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1404<p>The value produced is the integer or floating point difference of
1405the two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1406<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1407<pre> &lt;result&gt; = sub int 4, %var <i>; yields {int}:result = 4 - %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1408 &lt;result&gt; = sub int 0, %val <i>; yields {int}:result = -%var</i>
1409</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1410</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1411<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1412<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1413Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1414<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1415<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1416<pre> &lt;result&gt; = mul &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1417</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1418<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1419<p>The '<tt>mul</tt>' instruction returns the product of its two
1420operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1421<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1422<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1423 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1424values.
1425This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1426Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1427<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1428<p>The value produced is the integer or floating point product of the
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1429two operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1430<p>There is no signed vs unsigned multiplication. The appropriate
1431action is taken based on the type of the operand.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1432<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1433<pre> &lt;result&gt; = mul int 4, %var <i>; yields {int}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1434</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1435</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1436<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1437<div class="doc_subsubsection"> <a name="i_div">'<tt>div</tt>'
1438Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1439<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1440<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1441<pre> &lt;result&gt; = div &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1442</pre>
1443<h5>Overview:</h5>
1444<p>The '<tt>div</tt>' instruction returns the quotient of its two
1445operands.</p>
1446<h5>Arguments:</h5>
1447<p>The two arguments to the '<tt>div</tt>' instruction must be either <a
1448 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1449values.
1450This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1451Both arguments must have identical types.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1452<h5>Semantics:</h5>
1453<p>The value produced is the integer or floating point quotient of the
1454two operands.</p>
1455<h5>Example:</h5>
1456<pre> &lt;result&gt; = div int 4, %var <i>; yields {int}:result = 4 / %var</i>
1457</pre>
1458</div>
1459<!-- _______________________________________________________________________ -->
1460<div class="doc_subsubsection"> <a name="i_rem">'<tt>rem</tt>'
1461Instruction</a> </div>
1462<div class="doc_text">
1463<h5>Syntax:</h5>
1464<pre> &lt;result&gt; = rem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1465</pre>
1466<h5>Overview:</h5>
1467<p>The '<tt>rem</tt>' instruction returns the remainder from the
1468division of its two operands.</p>
1469<h5>Arguments:</h5>
1470<p>The two arguments to the '<tt>rem</tt>' instruction must be either <a
1471 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1472values.
1473This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1474Both arguments must have identical types.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1475<h5>Semantics:</h5>
1476<p>This returns the <i>remainder</i> of a division (where the result
1477has the same sign as the divisor), not the <i>modulus</i> (where the
1478result has the same sign as the dividend) of a value. For more
1479information about the difference, see: <a
1480 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
1481Math Forum</a>.</p>
1482<h5>Example:</h5>
1483<pre> &lt;result&gt; = rem int 4, %var <i>; yields {int}:result = 4 % %var</i>
1484</pre>
1485</div>
1486<!-- _______________________________________________________________________ -->
1487<div class="doc_subsubsection"> <a name="i_setcc">'<tt>set<i>cc</i></tt>'
1488Instructions</a> </div>
1489<div class="doc_text">
1490<h5>Syntax:</h5>
1491<pre> &lt;result&gt; = seteq &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1492 &lt;result&gt; = setne &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1493 &lt;result&gt; = setlt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1494 &lt;result&gt; = setgt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1495 &lt;result&gt; = setle &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1496 &lt;result&gt; = setge &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1497</pre>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1498<h5>Overview:</h5>
1499<p>The '<tt>set<i>cc</i></tt>' family of instructions returns a boolean
1500value based on a comparison of their two operands.</p>
1501<h5>Arguments:</h5>
1502<p>The two arguments to the '<tt>set<i>cc</i></tt>' instructions must
1503be of <a href="#t_firstclass">first class</a> type (it is not possible
1504to compare '<tt>label</tt>'s, '<tt>array</tt>'s, '<tt>structure</tt>'
1505or '<tt>void</tt>' values, etc...). Both arguments must have identical
1506types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1507<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1508<p>The '<tt>seteq</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1509value if both operands are equal.<br>
1510The '<tt>setne</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1511value if both operands are unequal.<br>
1512The '<tt>setlt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1513value if the first operand is less than the second operand.<br>
1514The '<tt>setgt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1515value if the first operand is greater than the second operand.<br>
1516The '<tt>setle</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1517value if the first operand is less than or equal to the second operand.<br>
1518The '<tt>setge</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1519value if the first operand is greater than or equal to the second
1520operand.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1521<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1522<pre> &lt;result&gt; = seteq int 4, 5 <i>; yields {bool}:result = false</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1523 &lt;result&gt; = setne float 4, 5 <i>; yields {bool}:result = true</i>
1524 &lt;result&gt; = setlt uint 4, 5 <i>; yields {bool}:result = true</i>
1525 &lt;result&gt; = setgt sbyte 4, 5 <i>; yields {bool}:result = false</i>
1526 &lt;result&gt; = setle sbyte 4, 5 <i>; yields {bool}:result = true</i>
1527 &lt;result&gt; = setge sbyte 4, 5 <i>; yields {bool}:result = false</i>
1528</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1529</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1530<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1531<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
1532Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1533<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1534<p>Bitwise binary operators are used to do various forms of
1535bit-twiddling in a program. They are generally very efficient
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1536instructions and can commonly be strength reduced from other
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1537instructions. They require two operands, execute an operation on them,
1538and produce a single value. The resulting value of the bitwise binary
1539operators is always the same type as its first operand.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1540</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1541<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1542<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
1543Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1544<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1545<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1546<pre> &lt;result&gt; = and &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1547</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1548<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1549<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
1550its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1551<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1552<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1553 href="#t_integral">integral</a> values. Both arguments must have
1554identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1555<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1556<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1557<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1558<div style="align: center">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1559<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1560 <tbody>
1561 <tr>
1562 <td>In0</td>
1563 <td>In1</td>
1564 <td>Out</td>
1565 </tr>
1566 <tr>
1567 <td>0</td>
1568 <td>0</td>
1569 <td>0</td>
1570 </tr>
1571 <tr>
1572 <td>0</td>
1573 <td>1</td>
1574 <td>0</td>
1575 </tr>
1576 <tr>
1577 <td>1</td>
1578 <td>0</td>
1579 <td>0</td>
1580 </tr>
1581 <tr>
1582 <td>1</td>
1583 <td>1</td>
1584 <td>1</td>
1585 </tr>
1586 </tbody>
1587</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1588</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1589<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1590<pre> &lt;result&gt; = and int 4, %var <i>; yields {int}:result = 4 &amp; %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1591 &lt;result&gt; = and int 15, 40 <i>; yields {int}:result = 8</i>
1592 &lt;result&gt; = and int 4, 8 <i>; yields {int}:result = 0</i>
1593</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1594</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1595<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1596<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1597<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1598<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1599<pre> &lt;result&gt; = or &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1600</pre>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1601<h5>Overview:</h5>
1602<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
1603or of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1604<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1605<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1606 href="#t_integral">integral</a> values. Both arguments must have
1607identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1608<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1609<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1610<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1611<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1612<table border="1" cellspacing="0" cellpadding="4">
1613 <tbody>
1614 <tr>
1615 <td>In0</td>
1616 <td>In1</td>
1617 <td>Out</td>
1618 </tr>
1619 <tr>
1620 <td>0</td>
1621 <td>0</td>
1622 <td>0</td>
1623 </tr>
1624 <tr>
1625 <td>0</td>
1626 <td>1</td>
1627 <td>1</td>
1628 </tr>
1629 <tr>
1630 <td>1</td>
1631 <td>0</td>
1632 <td>1</td>
1633 </tr>
1634 <tr>
1635 <td>1</td>
1636 <td>1</td>
1637 <td>1</td>
1638 </tr>
1639 </tbody>
1640</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1641</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1642<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1643<pre> &lt;result&gt; = or int 4, %var <i>; yields {int}:result = 4 | %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1644 &lt;result&gt; = or int 15, 40 <i>; yields {int}:result = 47</i>
1645 &lt;result&gt; = or int 4, 8 <i>; yields {int}:result = 12</i>
1646</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1647</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1648<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1649<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
1650Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1651<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1652<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1653<pre> &lt;result&gt; = xor &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1654</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1655<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1656<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
1657or of its two operands. The <tt>xor</tt> is used to implement the
1658"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1659<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1660<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1661 href="#t_integral">integral</a> values. Both arguments must have
1662identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1663<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1664<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1665<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1666<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1667<table border="1" cellspacing="0" cellpadding="4">
1668 <tbody>
1669 <tr>
1670 <td>In0</td>
1671 <td>In1</td>
1672 <td>Out</td>
1673 </tr>
1674 <tr>
1675 <td>0</td>
1676 <td>0</td>
1677 <td>0</td>
1678 </tr>
1679 <tr>
1680 <td>0</td>
1681 <td>1</td>
1682 <td>1</td>
1683 </tr>
1684 <tr>
1685 <td>1</td>
1686 <td>0</td>
1687 <td>1</td>
1688 </tr>
1689 <tr>
1690 <td>1</td>
1691 <td>1</td>
1692 <td>0</td>
1693 </tr>
1694 </tbody>
1695</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1696</div>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1697<p> </p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1698<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1699<pre> &lt;result&gt; = xor int 4, %var <i>; yields {int}:result = 4 ^ %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1700 &lt;result&gt; = xor int 15, 40 <i>; yields {int}:result = 39</i>
1701 &lt;result&gt; = xor int 4, 8 <i>; yields {int}:result = 12</i>
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1702 &lt;result&gt; = xor int %V, -1 <i>; yields {int}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1703</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1704</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1705<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1706<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
1707Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1708<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1709<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1710<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, ubyte &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1711</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1712<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1713<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
1714the left a specified number of bits.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1715<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1716<p>The first argument to the '<tt>shl</tt>' instruction must be an <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1717 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
1718type.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1719<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1720<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1721<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1722<pre> &lt;result&gt; = shl int 4, ubyte %var <i>; yields {int}:result = 4 &lt;&lt; %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1723 &lt;result&gt; = shl int 4, ubyte 2 <i>; yields {int}:result = 16</i>
1724 &lt;result&gt; = shl int 1, ubyte 10 <i>; yields {int}:result = 1024</i>
1725</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1726</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1727<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1728<div class="doc_subsubsection"> <a name="i_shr">'<tt>shr</tt>'
1729Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1730<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1731<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1732<pre> &lt;result&gt; = shr &lt;ty&gt; &lt;var1&gt;, ubyte &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1733</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1734<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1735<p>The '<tt>shr</tt>' instruction returns the first operand shifted to
1736the right a specified number of bits.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1737<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1738<p>The first argument to the '<tt>shr</tt>' instruction must be an <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1739 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
1740type.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1741<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1742<p>If the first argument is a <a href="#t_signed">signed</a> type, the
1743most significant bit is duplicated in the newly free'd bit positions.
1744If the first argument is unsigned, zero bits shall fill the empty
1745positions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1746<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1747<pre> &lt;result&gt; = shr int 4, ubyte %var <i>; yields {int}:result = 4 &gt;&gt; %var</i>
Chris Lattner33426d92003-06-18 21:30:51 +0000[diff] [blame]1748 &lt;result&gt; = shr uint 4, ubyte 1 <i>; yields {uint}:result = 2</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1749 &lt;result&gt; = shr int 4, ubyte 2 <i>; yields {int}:result = 1</i>
Chris Lattner33426d92003-06-18 21:30:51 +0000[diff] [blame]1750 &lt;result&gt; = shr sbyte 4, ubyte 3 <i>; yields {sbyte}:result = 0</i>
1751 &lt;result&gt; = shr sbyte -2, ubyte 1 <i>; yields {sbyte}:result = -1</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1752</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1753</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1754<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1755<div class="doc_subsection"> <a name="memoryops">Memory Access
1756Operations</a></div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1757<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1758<p>A key design point of an SSA-based representation is how it
1759represents memory. In LLVM, no memory locations are in SSA form, which
1760makes things very simple. This section describes how to read, write,
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1761allocate, and free memory in LLVM.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1762</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1763<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1764<div class="doc_subsubsection"> <a name="i_malloc">'<tt>malloc</tt>'
1765Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1766<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1767<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1768<pre> &lt;result&gt; = malloc &lt;type&gt;, uint &lt;NumElements&gt; <i>; yields {type*}:result</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1769 &lt;result&gt; = malloc &lt;type&gt; <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1770</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1771<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1772<p>The '<tt>malloc</tt>' instruction allocates memory from the system
1773heap and returns a pointer to it.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1774<h5>Arguments:</h5>
John Criswella92e5862004-02-24 16:13:56 +0000[diff] [blame]1775<p>The '<tt>malloc</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
1776bytes of memory from the operating system and returns a pointer of the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1777appropriate type to the program. The second form of the instruction is
1778a shorter version of the first instruction that defaults to allocating
1779one element.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1780<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1781<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1782<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
1783a pointer is returned.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1784<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1785<pre> %array = malloc [4 x ubyte ] <i>; yields {[%4 x ubyte]*}:array</i>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1786
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1787 %size = <a
1788 href="#i_add">add</a> uint 2, 2 <i>; yields {uint}:size = uint 4</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1789 %array1 = malloc ubyte, uint 4 <i>; yields {ubyte*}:array1</i>
1790 %array2 = malloc [12 x ubyte], uint %size <i>; yields {[12 x ubyte]*}:array2</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1791</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1792</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1793<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1794<div class="doc_subsubsection"> <a name="i_free">'<tt>free</tt>'
1795Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1796<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1797<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1798<pre> free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1799</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1800<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1801<p>The '<tt>free</tt>' instruction returns memory back to the unused
1802memory heap, to be reallocated in the future.</p>
1803<p> </p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1804<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1805<p>'<tt>value</tt>' shall be a pointer value that points to a value
1806that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
1807instruction.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1808<h5>Semantics:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1809<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1810after this instruction executes.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1811<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1812<pre> %array = <a href="#i_malloc">malloc</a> [4 x ubyte] <i>; yields {[4 x ubyte]*}:array</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1813 free [4 x ubyte]* %array
1814</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1815</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1816<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1817<div class="doc_subsubsection"> <a name="i_alloca">'<tt>alloca</tt>'
1818Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1819<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1820<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1821<pre> &lt;result&gt; = alloca &lt;type&gt;, uint &lt;NumElements&gt; <i>; yields {type*}:result</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1822 &lt;result&gt; = alloca &lt;type&gt; <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1823</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1824<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1825<p>The '<tt>alloca</tt>' instruction allocates memory on the current
1826stack frame of the procedure that is live until the current function
1827returns to its caller.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1828<h5>Arguments:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1829<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1830bytes of memory on the runtime stack, returning a pointer of the
1831appropriate type to the program. The second form of the instruction is
1832a shorter version of the first that defaults to allocating one element.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1833<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1834<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1835<p>Memory is allocated, a pointer is returned. '<tt>alloca</tt>'d
1836memory is automatically released when the function returns. The '<tt>alloca</tt>'
1837instruction is commonly used to represent automatic variables that must
1838have an address available. When the function returns (either with the <tt><a
1839 href="#i_ret">ret</a></tt> or <tt><a href="#i_invoke">invoke</a></tt>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1840instructions), the memory is reclaimed.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1841<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1842<pre> %ptr = alloca int <i>; yields {int*}:ptr</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1843 %ptr = alloca int, uint 4 <i>; yields {int*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1844</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1845</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1846<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1847<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
1848Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1849<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1850<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1851<pre> &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;<br> &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;<br></pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1852<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1853<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1854<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1855<p>The argument to the '<tt>load</tt>' instruction specifies the memory
1856address to load from. The pointer must point to a <a
Chris Lattner10ee9652004-06-03 22:57:15 +0000[diff] [blame]1857 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1858marked as <tt>volatile</tt> then the optimizer is not allowed to modify
1859the number or order of execution of this <tt>load</tt> with other
1860volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
1861instructions. </p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1862<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1863<p>The location of memory pointed to is loaded.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1864<h5>Examples:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1865<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
1866 <a
1867 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1868 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
1869</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1870</div>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1871<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1872<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
1873Instruction</a> </div>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1874<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1875<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; <i>; yields {void}</i>
Chris Lattner12d456c2003-09-08 18:27:49 +0000[diff] [blame]1876 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1877</pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1878<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1879<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1880<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1881<p>There are two arguments to the '<tt>store</tt>' instruction: a value
1882to store and an address to store it into. The type of the '<tt>&lt;pointer&gt;</tt>'
1883operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
1884operand. If the <tt>store</tt> is marked as <tt>volatile</tt> then the
1885optimizer is not allowed to modify the number or order of execution of
1886this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
1887 href="#i_store">store</a></tt> instructions.</p>
1888<h5>Semantics:</h5>
1889<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
1890at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1891<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1892<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
1893 <a
1894 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1895 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
1896</pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]1897<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1898<div class="doc_subsubsection">
1899 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
1900</div>
1901
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1902<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1903<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1904<pre>
1905 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
1906</pre>
1907
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1908<h5>Overview:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1909
1910<p>
1911The '<tt>getelementptr</tt>' instruction is used to get the address of a
1912subelement of an aggregate data structure.</p>
1913
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1914<h5>Arguments:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1915
1916<p>This instruction takes a list of integer constants that indicate what
1917elements of the aggregate object to index to. The actual types of the arguments
1918provided depend on the type of the first pointer argument. The
1919'<tt>getelementptr</tt>' instruction is used to index down through the type
1920levels of a structure. When indexing into a structure, only <tt>uint</tt>
1921integer constants are allowed. When indexing into an array or pointer
1922<tt>int</tt> and <tt>long</tt> indexes are allowed of any sign.</p>
1923
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1924<p>For example, let's consider a C code fragment and how it gets
1925compiled to LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1926
1927<pre>
1928 struct RT {
1929 char A;
1930 int B[10][20];
1931 char C;
1932 };
1933 struct ST {
1934 int X;
1935 double Y;
1936 struct RT Z;
1937 };
1938
1939 int *foo(struct ST *s) {
1940 return &amp;s[1].Z.B[5][13];
1941 }
1942</pre>
1943
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1944<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1945
1946<pre>
1947 %RT = type { sbyte, [10 x [20 x int]], sbyte }
1948 %ST = type { int, double, %RT }
1949
Brian Gaeke317ef962004-07-02 21:08:14 +0000[diff] [blame]1950 implementation
1951
1952 int* %foo(%ST* %s) {
1953 entry:
1954 %reg = getelementptr %ST* %s, int 1, uint 2, uint 1, int 5, int 13
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1955 ret int* %reg
1956 }
1957</pre>
1958
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1959<h5>Semantics:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1960
1961<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
Chris Lattner10ee9652004-06-03 22:57:15 +0000[diff] [blame]1962on the pointer type that is being index into. <a href="#t_pointer">Pointer</a>
1963and <a href="#t_array">array</a> types require <tt>uint</tt>, <tt>int</tt>,
1964<tt>ulong</tt>, or <tt>long</tt> values, and <a href="#t_struct">structure</a>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1965types require <tt>uint</tt> <b>constants</b>.</p>
1966
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1967<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1968type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ int, double, %RT
1969}</tt>' type, a structure. The second index indexes into the third element of
1970the structure, yielding a '<tt>%RT</tt>' = '<tt>{ sbyte, [10 x [20 x int]],
1971sbyte }</tt>' type, another structure. The third index indexes into the second
1972element of the structure, yielding a '<tt>[10 x [20 x int]]</tt>' type, an
1973array. The two dimensions of the array are subscripted into, yielding an
1974'<tt>int</tt>' type. The '<tt>getelementptr</tt>' instruction return a pointer
1975to this element, thus computing a value of '<tt>int*</tt>' type.</p>
1976
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1977<p>Note that it is perfectly legal to index partially through a
1978structure, returning a pointer to an inner element. Because of this,
1979the LLVM code for the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1980
1981<pre>
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]1982 int* %foo(%ST* %s) {
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1983 %t1 = getelementptr %ST* %s, int 1 <i>; yields %ST*:%t1</i>
1984 %t2 = getelementptr %ST* %t1, int 0, uint 2 <i>; yields %RT*:%t2</i>
1985 %t3 = getelementptr %RT* %t2, int 0, uint 1 <i>; yields [10 x [20 x int]]*:%t3</i>
1986 %t4 = getelementptr [10 x [20 x int]]* %t3, int 0, int 5 <i>; yields [20 x int]*:%t4</i>
1987 %t5 = getelementptr [20 x int]* %t4, int 0, int 13 <i>; yields int*:%t5</i>
1988 ret int* %t5
1989 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]1990</pre>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1991<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]1992<pre>
1993 <i>; yields [12 x ubyte]*:aptr</i>
1994 %aptr = getelementptr {int, [12 x ubyte]}* %sptr, long 0, uint 1
1995</pre>
1996
1997</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1998<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1999<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2000<div class="doc_text">
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]2001<p>The instructions in this category are the "miscellaneous"
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2002instructions, which defy better classification.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2003</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2004<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2005<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
2006Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2007<div class="doc_text">
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]2008<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2009<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]2010<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2011<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
2012the SSA graph representing the function.</p>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]2013<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2014<p>The type of the incoming values are specified with the first type
2015field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
2016as arguments, with one pair for each predecessor basic block of the
2017current block. Only values of <a href="#t_firstclass">first class</a>
2018type may be used as the value arguments to the PHI node. Only labels
2019may be used as the label arguments.</p>
2020<p>There must be no non-phi instructions between the start of a basic
2021block and the PHI instructions: i.e. PHI instructions must be first in
2022a basic block.</p>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]2023<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2024<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
2025value specified by the parameter, depending on which basic block we
2026came from in the last <a href="#terminators">terminator</a> instruction.</p>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2027<h5>Example:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2028<pre>Loop: ; Infinite loop that counts from 0 on up...<br> %indvar = phi uint [ 0, %LoopHeader ], [ %nextindvar, %Loop ]<br> %nextindvar = add uint %indvar, 1<br> br label %Loop<br></pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2029</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2030
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2031<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2032<div class="doc_subsubsection">
2033 <a name="i_cast">'<tt>cast .. to</tt>' Instruction</a>
2034</div>
2035
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2036<div class="doc_text">
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2037
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2038<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2039
2040<pre>
2041 &lt;result&gt; = cast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2042</pre>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2043
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2044<h5>Overview:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2045
2046<p>
2047The '<tt>cast</tt>' instruction is used as the primitive means to convert
2048integers to floating point, change data type sizes, and break type safety (by
2049casting pointers).
2050</p>
2051
2052
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2053<h5>Arguments:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2054
2055<p>
2056The '<tt>cast</tt>' instruction takes a value to cast, which must be a first
2057class value, and a type to cast it to, which must also be a <a
2058href="#t_firstclass">first class</a> type.
2059</p>
2060
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2061<h5>Semantics:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2062
2063<p>
2064This instruction follows the C rules for explicit casts when determining how the
2065data being cast must change to fit in its new container.
2066</p>
2067
2068<p>
2069When casting to bool, any value that would be considered true in the context of
2070a C '<tt>if</tt>' condition is converted to the boolean '<tt>true</tt>' values,
2071all else are '<tt>false</tt>'.
2072</p>
2073
2074<p>
2075When extending an integral value from a type of one signness to another (for
2076example '<tt>sbyte</tt>' to '<tt>ulong</tt>'), the value is sign-extended if the
2077<b>source</b> value is signed, and zero-extended if the source value is
2078unsigned. <tt>bool</tt> values are always zero extended into either zero or
2079one.
2080</p>
2081
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]2082<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2083
2084<pre>
2085 %X = cast int 257 to ubyte <i>; yields ubyte:1</i>
Chris Lattnerd8f8ede2002-06-25 18:03:17 +0000[diff] [blame]2086 %Y = cast int 123 to bool <i>; yields bool:true</i>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]2087</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2088</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2089
2090<!-- _______________________________________________________________________ -->
2091<div class="doc_subsubsection">
2092 <a name="i_select">'<tt>select</tt>' Instruction</a>
2093</div>
2094
2095<div class="doc_text">
2096
2097<h5>Syntax:</h5>
2098
2099<pre>
2100 &lt;result&gt; = select bool &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
2101</pre>
2102
2103<h5>Overview:</h5>
2104
2105<p>
2106The '<tt>select</tt>' instruction is used to choose one value based on a
2107condition, without branching.
2108</p>
2109
2110
2111<h5>Arguments:</h5>
2112
2113<p>
2114The '<tt>select</tt>' instruction requires a boolean value indicating the condition, and two values of the same <a href="#t_firstclass">first class</a> type.
2115</p>
2116
2117<h5>Semantics:</h5>
2118
2119<p>
2120If the boolean condition evaluates to true, the instruction returns the first
2121value argument, otherwise it returns the second value argument.
2122</p>
2123
2124<h5>Example:</h5>
2125
2126<pre>
2127 %X = select bool true, ubyte 17, ubyte 42 <i>; yields ubyte:17</i>
2128</pre>
2129</div>
2130
2131
2132
2133
2134
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]2135<!-- _______________________________________________________________________ -->
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2136<div class="doc_subsubsection">
2137 <a name="i_call">'<tt>call</tt>' Instruction</a>
2138</div>
2139
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2140<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2141
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2142<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2143<pre>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2144 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] &lt;ty&gt;* &lt;fnptrval&gt;(&lt;param list&gt;)
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2145</pre>
2146
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2147<h5>Overview:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2148
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2149<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2150
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2151<h5>Arguments:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2152
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2153<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2154
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2155<ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2156 <li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2157 <p>The optional "tail" marker indicates whether the callee function accesses
2158 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2159 function call is eligible for tail call optimization. Note that calls may
2160 be marked "tail" even if they do not occur before a <a
2161 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2162 </li>
2163 <li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2164 <p>The optional "cconv" marker indicates which <a href="callingconv">calling
2165 convention</a> the call should use. If none is specified, the call defaults
2166 to using C calling conventions.
2167 </li>
2168 <li>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2169 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
2170 being invoked. The argument types must match the types implied by this
2171 signature.</p>
2172 </li>
2173 <li>
2174 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
2175 be invoked. In most cases, this is a direct function invocation, but
2176 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
2177 to function values.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2178 </li>
2179 <li>
2180 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencerd845d162005-05-01 22:22:57 +0000[diff] [blame]2181 function signature argument types. All arguments must be of
2182 <a href="#t_firstclass">first class</a> type. If the function signature
2183 indicates the function accepts a variable number of arguments, the extra
2184 arguments can be specified.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2185 </li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2186</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2187
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2188<h5>Semantics:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2189
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2190<p>The '<tt>call</tt>' instruction is used to cause control flow to
2191transfer to a specified function, with its incoming arguments bound to
2192the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
2193instruction in the called function, control flow continues with the
2194instruction after the function call, and the return value of the
2195function is bound to the result argument. This is a simpler case of
2196the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2197
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2198<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2199
2200<pre>
2201 %retval = call int %test(int %argc)
2202 call int(sbyte*, ...) *%printf(sbyte* %msg, int 12, sbyte 42);
2203 %X = tail call int %foo()
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2204 %Y = tail call <a href="#callingconv">fastcc</a> int %foo()
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]2205</pre>
2206
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2207</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2208
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2209<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2210<div class="doc_subsubsection">
2211 <a name="i_vanext">'<tt>vanext</tt>' Instruction</a>
2212</div>
2213
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2214<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2215
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2216<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2217
2218<pre>
2219 &lt;resultarglist&gt; = vanext &lt;va_list&gt; &lt;arglist&gt;, &lt;argty&gt;
2220</pre>
2221
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2222<h5>Overview:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2223
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2224<p>The '<tt>vanext</tt>' instruction is used to access arguments passed
2225through the "variable argument" area of a function call. It is used to
2226implement the <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2227
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2228<h5>Arguments:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2229
2230<p>This instruction takes a <tt>va_list</tt> value and the type of the
2231argument. It returns another <tt>va_list</tt>. The actual type of
2232<tt>va_list</tt> may be defined differently for different targets. Most targets
2233use a <tt>va_list</tt> type of <tt>sbyte*</tt> or some other pointer type.</p>
2234
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2235<h5>Semantics:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2236
2237<p>The '<tt>vanext</tt>' instruction advances the specified <tt>va_list</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2238past an argument of the specified type. In conjunction with the <a
2239 href="#i_vaarg"><tt>vaarg</tt></a> instruction, it is used to implement
2240the <tt>va_arg</tt> macro available in C. For more information, see
2241the variable argument handling <a href="#int_varargs">Intrinsic
2242Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2243
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2244<p>It is legal for this instruction to be called in a function which
2245does not take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2246function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2247
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2248<p><tt>vanext</tt> is an LLVM instruction instead of an <a
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2249href="#intrinsics">intrinsic function</a> because it takes a type as an
2250argument. The type refers to the current argument in the <tt>va_list</tt>, it
2251tells the compiler how far on the stack it needs to advance to find the next
2252argument</p>
2253
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2254<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2255
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2256<p>See the <a href="#int_varargs">variable argument processing</a>
2257section.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2258
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2259</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2260
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]2261<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2262<div class="doc_subsubsection">
2263 <a name="i_vaarg">'<tt>vaarg</tt>' Instruction</a>
2264</div>
2265
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2266<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2267
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]2268<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2269
2270<pre>
2271 &lt;resultval&gt; = vaarg &lt;va_list&gt; &lt;arglist&gt;, &lt;argty&gt;
2272</pre>
2273
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]2274<h5>Overview:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2275
2276<p>The '<tt>vaarg</tt>' instruction is used to access arguments passed through
2277the "variable argument" area of a function call. It is used to implement the
2278<tt>va_arg</tt> macro in C.</p>
2279
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]2280<h5>Arguments:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2281
2282<p>This instruction takes a <tt>va_list</tt> value and the type of the
2283argument. It returns a value of the specified argument type. Again, the actual
2284type of <tt>va_list</tt> is target specific.</p>
2285
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]2286<h5>Semantics:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2287
2288<p>The '<tt>vaarg</tt>' instruction loads an argument of the specified type from
2289the specified <tt>va_list</tt>. In conjunction with the <a
2290href="#i_vanext"><tt>vanext</tt></a> instruction, it is used to implement the
2291<tt>va_arg</tt> macro available in C. For more information, see the variable
2292argument handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
2293
2294<p>It is legal for this instruction to be called in a function which does not
2295take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2296function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2297
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2298<p><tt>vaarg</tt> is an LLVM instruction instead of an <a
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2299href="#intrinsics">intrinsic function</a> because it takes an type as an
2300argument.</p>
2301
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]2302<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]2303
2304<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
2305
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2306</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]2307
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2308<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2309<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
2310<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]2311
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2312<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]2313
2314<p>LLVM supports the notion of an "intrinsic function". These functions have
2315well known names and semantics, and are required to follow certain
2316restrictions. Overall, these instructions represent an extension mechanism for
2317the LLVM language that does not require changing all of the transformations in
2318LLVM to add to the language (or the bytecode reader/writer, the parser,
2319etc...).</p>
2320
2321<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix, this
2322prefix is reserved in LLVM for intrinsic names, thus functions may not be named
2323this. Intrinsic functions must always be external functions: you cannot define
2324the body of intrinsic functions. Intrinsic functions may only be used in call
2325or invoke instructions: it is illegal to take the address of an intrinsic
2326function. Additionally, because intrinsic functions are part of the LLVM
2327language, it is required that they all be documented here if any are added.</p>
2328
2329
2330<p>
2331Adding an intrinsic to LLVM is straight-forward if it is possible to express the
2332concept in LLVM directly (ie, code generator support is not _required_). To do
2333this, extend the default implementation of the IntrinsicLowering class to handle
2334the intrinsic. Code generators use this class to lower intrinsics they do not
2335understand to raw LLVM instructions that they do.
2336</p>
2337
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2338</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]2339
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2340<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]2341<div class="doc_subsection">
2342 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
2343</div>
2344
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2345<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2346
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2347<p>Variable argument support is defined in LLVM with the <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2348 href="#i_vanext"><tt>vanext</tt></a> instruction and these three
2349intrinsic functions. These functions are related to the similarly
2350named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2351
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2352<p>All of these functions operate on arguments that use a
2353target-specific value type "<tt>va_list</tt>". The LLVM assembly
2354language reference manual does not define what this type is, so all
2355transformations should be prepared to handle intrinsics with any type
2356used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2357
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2358<p>This example shows how the <a href="#i_vanext"><tt>vanext</tt></a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2359instruction and the variable argument handling intrinsic functions are
2360used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2361
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]2362<pre>
2363int %test(int %X, ...) {
2364 ; Initialize variable argument processing
2365 %ap = call sbyte* %<a href="#i_va_start">llvm.va_start</a>()
2366
2367 ; Read a single integer argument
2368 %tmp = vaarg sbyte* %ap, int
2369
2370 ; Advance to the next argument
2371 %ap2 = vanext sbyte* %ap, int
2372
2373 ; Demonstrate usage of llvm.va_copy and llvm.va_end
2374 %aq = call sbyte* %<a href="#i_va_copy">llvm.va_copy</a>(sbyte* %ap2)
2375 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte* %aq)
2376
2377 ; Stop processing of arguments.
2378 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte* %ap2)
2379 ret int %tmp
2380}
2381</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2382</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]2383
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2384<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]2385<div class="doc_subsubsection">
2386 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
2387</div>
2388
2389
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2390<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2391<h5>Syntax:</h5>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]2392<pre> declare &lt;va_list&gt; %llvm.va_start()<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2393<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2394<p>The '<tt>llvm.va_start</tt>' intrinsic returns a new <tt>&lt;arglist&gt;</tt>
2395for subsequent use by the variable argument intrinsics.</p>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2396<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2397<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2398macro available in C. In a target-dependent way, it initializes and
2399returns a <tt>va_list</tt> element, so that the next <tt>vaarg</tt>
2400will produce the first variable argument passed to the function. Unlike
2401the C <tt>va_start</tt> macro, this intrinsic does not need to know the
2402last argument of the function, the compiler can figure that out.</p>
2403<p>Note that this intrinsic function is only legal to be called from
2404within the body of a variable argument function.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2405</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]2406
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2407<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]2408<div class="doc_subsubsection">
2409 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
2410</div>
2411
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2412<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2413<h5>Syntax:</h5>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]2414<pre> declare void %llvm.va_end(&lt;va_list&gt; &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2415<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2416<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
2417which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
2418or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2419<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2420<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2421<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2422<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2423macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
2424Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
2425 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
2426with calls to <tt>llvm.va_end</tt>.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2427</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]2428
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2429<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]2430<div class="doc_subsubsection">
2431 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
2432</div>
2433
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2434<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2435
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2436<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2437
2438<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]2439 declare &lt;va_list&gt; %llvm.va_copy(&lt;va_list&gt; &lt;destarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2440</pre>
2441
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2442<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2443
2444<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
2445from the source argument list to the destination argument list.</p>
2446
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2447<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2448
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2449<p>The argument is the <tt>va_list</tt> to copy.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2450
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]2451<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2452
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2453<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2454macro available in C. In a target-dependent way, it copies the source
2455<tt>va_list</tt> element into the returned list. This intrinsic is necessary
Chris Lattner53e5e2a2004-06-21 22:52:48 +0000[diff] [blame]2456because the <tt><a href="#i_va_start">llvm.va_start</a></tt> intrinsic may be
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2457arbitrarily complex and require memory allocation, for example.</p>
2458
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2459</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]2460
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]2461<!-- ======================================================================= -->
2462<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2463 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
2464</div>
2465
2466<div class="doc_text">
2467
2468<p>
2469LLVM support for <a href="GarbageCollection.html">Accurate Garbage
2470Collection</a> requires the implementation and generation of these intrinsics.
2471These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
2472stack</a>, as well as garbage collector implementations that require <a
2473href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
2474Front-ends for type-safe garbage collected languages should generate these
2475intrinsics to make use of the LLVM garbage collectors. For more details, see <a
2476href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
2477</p>
2478</div>
2479
2480<!-- _______________________________________________________________________ -->
2481<div class="doc_subsubsection">
2482 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
2483</div>
2484
2485<div class="doc_text">
2486
2487<h5>Syntax:</h5>
2488
2489<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]2490 declare void %llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2491</pre>
2492
2493<h5>Overview:</h5>
2494
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2495<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2496the code generator, and allows some metadata to be associated with it.</p>
2497
2498<h5>Arguments:</h5>
2499
2500<p>The first argument specifies the address of a stack object that contains the
2501root pointer. The second pointer (which must be either a constant or a global
2502value address) contains the meta-data to be associated with the root.</p>
2503
2504<h5>Semantics:</h5>
2505
2506<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
2507location. At compile-time, the code generator generates information to allow
2508the runtime to find the pointer at GC safe points.
2509</p>
2510
2511</div>
2512
2513
2514<!-- _______________________________________________________________________ -->
2515<div class="doc_subsubsection">
2516 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
2517</div>
2518
2519<div class="doc_text">
2520
2521<h5>Syntax:</h5>
2522
2523<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]2524 declare sbyte* %llvm.gcread(sbyte** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2525</pre>
2526
2527<h5>Overview:</h5>
2528
2529<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
2530locations, allowing garbage collector implementations that require read
2531barriers.</p>
2532
2533<h5>Arguments:</h5>
2534
2535<p>The argument is the address to read from, which should be an address
2536allocated from the garbage collector.</p>
2537
2538<h5>Semantics:</h5>
2539
2540<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
2541instruction, but may be replaced with substantially more complex code by the
2542garbage collector runtime, as needed.</p>
2543
2544</div>
2545
2546
2547<!-- _______________________________________________________________________ -->
2548<div class="doc_subsubsection">
2549 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
2550</div>
2551
2552<div class="doc_text">
2553
2554<h5>Syntax:</h5>
2555
2556<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]2557 declare void %llvm.gcwrite(sbyte* %P1, sbyte** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]2558</pre>
2559
2560<h5>Overview:</h5>
2561
2562<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
2563locations, allowing garbage collector implementations that require write
2564barriers (such as generational or reference counting collectors).</p>
2565
2566<h5>Arguments:</h5>
2567
2568<p>The first argument is the reference to store, and the second is the heap
2569location to store to.</p>
2570
2571<h5>Semantics:</h5>
2572
2573<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
2574instruction, but may be replaced with substantially more complex code by the
2575garbage collector runtime, as needed.</p>
2576
2577</div>
2578
2579
2580
2581<!-- ======================================================================= -->
2582<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]2583 <a name="int_codegen">Code Generator Intrinsics</a>
2584</div>
2585
2586<div class="doc_text">
2587<p>
2588These intrinsics are provided by LLVM to expose special features that may only
2589be implemented with code generator support.
2590</p>
2591
2592</div>
2593
2594<!-- _______________________________________________________________________ -->
2595<div class="doc_subsubsection">
2596 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
2597</div>
2598
2599<div class="doc_text">
2600
2601<h5>Syntax:</h5>
2602<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]2603 declare void* %llvm.returnaddress(uint &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]2604</pre>
2605
2606<h5>Overview:</h5>
2607
2608<p>
2609The '<tt>llvm.returnaddress</tt>' intrinsic returns a target-specific value
2610indicating the return address of the current function or one of its callers.
2611</p>
2612
2613<h5>Arguments:</h5>
2614
2615<p>
2616The argument to this intrinsic indicates which function to return the address
2617for. Zero indicates the calling function, one indicates its caller, etc. The
2618argument is <b>required</b> to be a constant integer value.
2619</p>
2620
2621<h5>Semantics:</h5>
2622
2623<p>
2624The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
2625the return address of the specified call frame, or zero if it cannot be
2626identified. The value returned by this intrinsic is likely to be incorrect or 0
2627for arguments other than zero, so it should only be used for debugging purposes.
2628</p>
2629
2630<p>
2631Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]2632aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]2633source-language caller.
2634</p>
2635</div>
2636
2637
2638<!-- _______________________________________________________________________ -->
2639<div class="doc_subsubsection">
2640 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
2641</div>
2642
2643<div class="doc_text">
2644
2645<h5>Syntax:</h5>
2646<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]2647 declare void* %llvm.frameaddress(uint &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]2648</pre>
2649
2650<h5>Overview:</h5>
2651
2652<p>
2653The '<tt>llvm.frameaddress</tt>' intrinsic returns the target-specific frame
2654pointer value for the specified stack frame.
2655</p>
2656
2657<h5>Arguments:</h5>
2658
2659<p>
2660The argument to this intrinsic indicates which function to return the frame
2661pointer for. Zero indicates the calling function, one indicates its caller,
2662etc. The argument is <b>required</b> to be a constant integer value.
2663</p>
2664
2665<h5>Semantics:</h5>
2666
2667<p>
2668The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
2669the frame address of the specified call frame, or zero if it cannot be
2670identified. The value returned by this intrinsic is likely to be incorrect or 0
2671for arguments other than zero, so it should only be used for debugging purposes.
2672</p>
2673
2674<p>
2675Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]2676aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]2677source-language caller.
2678</p>
2679</div>
2680
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]2681<!-- _______________________________________________________________________ -->
2682<div class="doc_subsubsection">
2683 <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
2684</div>
2685
2686<div class="doc_text">
2687
2688<h5>Syntax:</h5>
2689<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]2690 declare void %llvm.prefetch(sbyte * &lt;address&gt;,
2691 uint &lt;rw&gt;, uint &lt;locality&gt;)
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]2692</pre>
2693
2694<h5>Overview:</h5>
2695
2696
2697<p>
2698The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
2699a prefetch instruction if supported, otherwise it is a noop. Prefetches have no
Chris Lattnerff851072005-02-28 19:47:14 +0000[diff] [blame]2700effect on the behavior of the program, but can change its performance
2701characteristics.
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]2702</p>
2703
2704<h5>Arguments:</h5>
2705
2706<p>
2707<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
2708determining if the fetch should be for a read (0) or write (1), and
2709<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattnerd3e641c2005-03-07 20:31:38 +0000[diff] [blame]2710locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]2711<tt>locality</tt> arguments must be constant integers.
2712</p>
2713
2714<h5>Semantics:</h5>
2715
2716<p>
2717This intrinsic does not modify the behavior of the program. In particular,
2718prefetches cannot trap and do not produce a value. On targets that support this
2719intrinsic, the prefetch can provide hints to the processor cache for better
2720performance.
2721</p>
2722
2723</div>
2724
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]2725<!-- _______________________________________________________________________ -->
2726<div class="doc_subsubsection">
2727 <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
2728</div>
2729
2730<div class="doc_text">
2731
2732<h5>Syntax:</h5>
2733<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]2734 declare void %llvm.pcmarker( uint &lt;id&gt; )
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]2735</pre>
2736
2737<h5>Overview:</h5>
2738
2739
2740<p>
2741The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a PC in a region of
2742code to simulators and other tools. The method is target specific, but it is
2743expected that the marker will use exported symbols to transmit the PC of the marker.
2744The marker makes no guaranties that it will remain with any specific instruction
2745after optimizations. It is possible that the presense of a marker will inhibit
2746optimizations. The intended use is to be inserted after optmizations to allow
2747corrolations of simulation runs.
2748</p>
2749
2750<h5>Arguments:</h5>
2751
2752<p>
2753<tt>id</tt> is a numerical id identifying the marker.
2754</p>
2755
2756<h5>Semantics:</h5>
2757
2758<p>
2759This intrinsic does not modify the behavior of the program. Backends that do not
2760support this intrinisic may ignore it.
2761</p>
2762
2763</div>
2764
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]2765
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]2766<!-- ======================================================================= -->
2767<div class="doc_subsection">
2768 <a name="int_os">Operating System Intrinsics</a>
2769</div>
2770
2771<div class="doc_text">
2772<p>
2773These intrinsics are provided by LLVM to support the implementation of
2774operating system level code.
2775</p>
2776
2777</div>
John Criswella4501222004-04-12 15:02:16 +0000[diff] [blame]2778
John Criswell508b93c2004-04-09 15:23:37 +0000[diff] [blame]2779<!-- _______________________________________________________________________ -->
2780<div class="doc_subsubsection">
2781 <a name="i_readport">'<tt>llvm.readport</tt>' Intrinsic</a>
2782</div>
2783
2784<div class="doc_text">
2785
2786<h5>Syntax:</h5>
2787<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]2788 declare &lt;integer type&gt; %llvm.readport (&lt;integer type&gt; &lt;address&gt;)
John Criswell508b93c2004-04-09 15:23:37 +0000[diff] [blame]2789</pre>
2790
2791<h5>Overview:</h5>
2792
2793<p>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]2794The '<tt>llvm.readport</tt>' intrinsic reads data from the specified hardware
2795I/O port.
John Criswell508b93c2004-04-09 15:23:37 +0000[diff] [blame]2796</p>
2797
2798<h5>Arguments:</h5>
2799
2800<p>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]2801The argument to this intrinsic indicates the hardware I/O address from which
2802to read the data. The address is in the hardware I/O address namespace (as
2803opposed to being a memory location for memory mapped I/O).
John Criswell508b93c2004-04-09 15:23:37 +0000[diff] [blame]2804</p>
2805
2806<h5>Semantics:</h5>
2807
2808<p>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]2809The '<tt>llvm.readport</tt>' intrinsic reads data from the hardware I/O port
2810specified by <i>address</i> and returns the value. The address and return
2811value must be integers, but the size is dependent upon the platform upon which
2812the program is code generated. For example, on x86, the address must be an
Misha Brukman36c6bc12005-04-22 18:02:52 +0000[diff] [blame]2813unsigned 16-bit value, and the return value must be 8, 16, or 32 bits.
John Criswell508b93c2004-04-09 15:23:37 +0000[diff] [blame]2814</p>
2815
2816</div>
2817
2818<!-- _______________________________________________________________________ -->
2819<div class="doc_subsubsection">
2820 <a name="i_writeport">'<tt>llvm.writeport</tt>' Intrinsic</a>
2821</div>
2822
2823<div class="doc_text">
2824
2825<h5>Syntax:</h5>
2826<pre>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2827 call void (&lt;integer type&gt;, &lt;integer type&gt;)*
2828 %llvm.writeport (&lt;integer type&gt; &lt;value&gt;,
2829 &lt;integer type&gt; &lt;address&gt;)
John Criswell508b93c2004-04-09 15:23:37 +0000[diff] [blame]2830</pre>
2831
2832<h5>Overview:</h5>
2833
2834<p>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]2835The '<tt>llvm.writeport</tt>' intrinsic writes data to the specified hardware
2836I/O port.
John Criswell508b93c2004-04-09 15:23:37 +0000[diff] [blame]2837</p>
2838
2839<h5>Arguments:</h5>
2840
2841<p>
John Criswell7a576472004-04-12 16:33:19 +0000[diff] [blame]2842The first argument is the value to write to the I/O port.
John Criswell508b93c2004-04-09 15:23:37 +0000[diff] [blame]2843</p>
2844
2845<p>
John Criswell7a576472004-04-12 16:33:19 +0000[diff] [blame]2846The second argument indicates the hardware I/O address to which data should be
2847written. The address is in the hardware I/O address namespace (as opposed to
2848being a memory location for memory mapped I/O).
John Criswell508b93c2004-04-09 15:23:37 +0000[diff] [blame]2849</p>
2850
2851<h5>Semantics:</h5>
2852
2853<p>
2854The '<tt>llvm.writeport</tt>' intrinsic writes <i>value</i> to the I/O port
2855specified by <i>address</i>. The address and value must be integers, but the
2856size is dependent upon the platform upon which the program is code generated.
Misha Brukman36c6bc12005-04-22 18:02:52 +0000[diff] [blame]2857For example, on x86, the address must be an unsigned 16-bit value, and the
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]2858value written must be 8, 16, or 32 bits in length.
John Criswell508b93c2004-04-09 15:23:37 +0000[diff] [blame]2859</p>
2860
2861</div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]2862
John Criswella4501222004-04-12 15:02:16 +0000[diff] [blame]2863<!-- _______________________________________________________________________ -->
2864<div class="doc_subsubsection">
2865 <a name="i_readio">'<tt>llvm.readio</tt>' Intrinsic</a>
2866</div>
2867
2868<div class="doc_text">
2869
2870<h5>Syntax:</h5>
2871<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]2872 declare &lt;result&gt; %llvm.readio (&lt;ty&gt; * &lt;pointer&gt;)
John Criswella4501222004-04-12 15:02:16 +0000[diff] [blame]2873</pre>
2874
2875<h5>Overview:</h5>
2876
2877<p>
2878The '<tt>llvm.readio</tt>' intrinsic reads data from a memory mapped I/O
2879address.
2880</p>
2881
2882<h5>Arguments:</h5>
2883
2884<p>
John Criswell7a576472004-04-12 16:33:19 +0000[diff] [blame]2885The argument to this intrinsic is a pointer indicating the memory address from
2886which to read the data. The data must be a
2887<a href="#t_firstclass">first class</a> type.
John Criswella4501222004-04-12 15:02:16 +0000[diff] [blame]2888</p>
2889
2890<h5>Semantics:</h5>
2891
2892<p>
2893The '<tt>llvm.readio</tt>' intrinsic reads data from a memory mapped I/O
John Criswell7a576472004-04-12 16:33:19 +0000[diff] [blame]2894location specified by <i>pointer</i> and returns the value. The argument must
2895be a pointer, and the return value must be a
2896<a href="#t_firstclass">first class</a> type. However, certain architectures
Misha Brukman36c6bc12005-04-22 18:02:52 +0000[diff] [blame]2897may not support I/O on all first class types. For example, 32-bit processors
John Criswell7a576472004-04-12 16:33:19 +0000[diff] [blame]2898may only support I/O on data types that are 32 bits or less.
John Criswella4501222004-04-12 15:02:16 +0000[diff] [blame]2899</p>
2900
2901<p>
John Criswell7a576472004-04-12 16:33:19 +0000[diff] [blame]2902This intrinsic enforces an in-order memory model for llvm.readio and
2903llvm.writeio calls on machines that use dynamic scheduling. Dynamically
2904scheduled processors may execute loads and stores out of order, re-ordering at
2905run time accesses to memory mapped I/O registers. Using these intrinsics
2906ensures that accesses to memory mapped I/O registers occur in program order.
John Criswella4501222004-04-12 15:02:16 +0000[diff] [blame]2907</p>
2908
2909</div>
2910
2911<!-- _______________________________________________________________________ -->
2912<div class="doc_subsubsection">
2913 <a name="i_writeio">'<tt>llvm.writeio</tt>' Intrinsic</a>
2914</div>
2915
2916<div class="doc_text">
2917
2918<h5>Syntax:</h5>
2919<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]2920 declare void %llvm.writeio (&lt;ty1&gt; &lt;value&gt;, &lt;ty2&gt; * &lt;pointer&gt;)
John Criswella4501222004-04-12 15:02:16 +0000[diff] [blame]2921</pre>
2922
2923<h5>Overview:</h5>
2924
2925<p>
2926The '<tt>llvm.writeio</tt>' intrinsic writes data to the specified memory
2927mapped I/O address.
2928</p>
2929
2930<h5>Arguments:</h5>
2931
2932<p>
John Criswell7a576472004-04-12 16:33:19 +0000[diff] [blame]2933The first argument is the value to write to the memory mapped I/O location.
2934The second argument is a pointer indicating the memory address to which the
2935data should be written.
John Criswella4501222004-04-12 15:02:16 +0000[diff] [blame]2936</p>
2937
2938<h5>Semantics:</h5>
2939
2940<p>
2941The '<tt>llvm.writeio</tt>' intrinsic writes <i>value</i> to the memory mapped
John Criswell7a576472004-04-12 16:33:19 +0000[diff] [blame]2942I/O address specified by <i>pointer</i>. The value must be a
2943<a href="#t_firstclass">first class</a> type. However, certain architectures
Misha Brukman36c6bc12005-04-22 18:02:52 +0000[diff] [blame]2944may not support I/O on all first class types. For example, 32-bit processors
John Criswell7a576472004-04-12 16:33:19 +0000[diff] [blame]2945may only support I/O on data types that are 32 bits or less.
John Criswella4501222004-04-12 15:02:16 +0000[diff] [blame]2946</p>
2947
2948<p>
John Criswell7a576472004-04-12 16:33:19 +0000[diff] [blame]2949This intrinsic enforces an in-order memory model for llvm.readio and
2950llvm.writeio calls on machines that use dynamic scheduling. Dynamically
2951scheduled processors may execute loads and stores out of order, re-ordering at
2952run time accesses to memory mapped I/O registers. Using these intrinsics
2953ensures that accesses to memory mapped I/O registers occur in program order.
John Criswella4501222004-04-12 15:02:16 +0000[diff] [blame]2954</p>
2955
2956</div>
2957
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]2958<!-- ======================================================================= -->
2959<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]2960 <a name="int_libc">Standard C Library Intrinsics</a>
2961</div>
2962
2963<div class="doc_text">
2964<p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]2965LLVM provides intrinsics for a few important standard C library functions.
2966These intrinsics allow source-language front-ends to pass information about the
2967alignment of the pointer arguments to the code generator, providing opportunity
2968for more efficient code generation.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]2969</p>
2970
2971</div>
2972
2973<!-- _______________________________________________________________________ -->
2974<div class="doc_subsubsection">
2975 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
2976</div>
2977
2978<div class="doc_text">
2979
2980<h5>Syntax:</h5>
2981<pre>
Reid Spencercf669d82005-04-26 20:41:16 +0000[diff] [blame]2982 declare void %llvm.memcpy(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
2983 uint &lt;len&gt;, uint &lt;align&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]2984</pre>
2985
2986<h5>Overview:</h5>
2987
2988<p>
2989The '<tt>llvm.memcpy</tt>' intrinsic copies a block of memory from the source
2990location to the destination location.
2991</p>
2992
2993<p>
2994Note that, unlike the standard libc function, the <tt>llvm.memcpy</tt> intrinsic
2995does not return a value, and takes an extra alignment argument.
2996</p>
2997
2998<h5>Arguments:</h5>
2999
3000<p>
3001The first argument is a pointer to the destination, the second is a pointer to
3002the source. The third argument is an (arbitrarily sized) integer argument
3003specifying the number of bytes to copy, and the fourth argument is the alignment
3004of the source and destination locations.
3005</p>
3006
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]3007<p>
3008If the call to this intrinisic has an alignment value that is not 0 or 1, then
3009the caller guarantees that the size of the copy is a multiple of the alignment
3010and that both the source and destination pointers are aligned to that boundary.
3011</p>
3012
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3013<h5>Semantics:</h5>
3014
3015<p>
3016The '<tt>llvm.memcpy</tt>' intrinsic copies a block of memory from the source
3017location to the destination location, which are not allowed to overlap. It
3018copies "len" bytes of memory over. If the argument is known to be aligned to
3019some boundary, this can be specified as the fourth argument, otherwise it should
3020be set to 0 or 1.
3021</p>
3022</div>
3023
3024
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]3025<!-- _______________________________________________________________________ -->
3026<div class="doc_subsubsection">
3027 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
3028</div>
3029
3030<div class="doc_text">
3031
3032<h5>Syntax:</h5>
3033<pre>
Reid Spencercf669d82005-04-26 20:41:16 +0000[diff] [blame]3034 declare void %llvm.memmove(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
3035 uint &lt;len&gt;, uint &lt;align&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]3036</pre>
3037
3038<h5>Overview:</h5>
3039
3040<p>
3041The '<tt>llvm.memmove</tt>' intrinsic moves a block of memory from the source
3042location to the destination location. It is similar to the '<tt>llvm.memcpy</tt>'
3043intrinsic but allows the two memory locations to overlap.
3044</p>
3045
3046<p>
3047Note that, unlike the standard libc function, the <tt>llvm.memmove</tt> intrinsic
3048does not return a value, and takes an extra alignment argument.
3049</p>
3050
3051<h5>Arguments:</h5>
3052
3053<p>
3054The first argument is a pointer to the destination, the second is a pointer to
3055the source. The third argument is an (arbitrarily sized) integer argument
3056specifying the number of bytes to copy, and the fourth argument is the alignment
3057of the source and destination locations.
3058</p>
3059
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]3060<p>
3061If the call to this intrinisic has an alignment value that is not 0 or 1, then
3062the caller guarantees that the size of the copy is a multiple of the alignment
3063and that both the source and destination pointers are aligned to that boundary.
3064</p>
3065
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]3066<h5>Semantics:</h5>
3067
3068<p>
3069The '<tt>llvm.memmove</tt>' intrinsic copies a block of memory from the source
3070location to the destination location, which may overlap. It
3071copies "len" bytes of memory over. If the argument is known to be aligned to
3072some boundary, this can be specified as the fourth argument, otherwise it should
3073be set to 0 or 1.
3074</p>
3075</div>
3076
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3077
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3078<!-- _______________________________________________________________________ -->
3079<div class="doc_subsubsection">
3080 <a name="i_memset">'<tt>llvm.memset</tt>' Intrinsic</a>
3081</div>
3082
3083<div class="doc_text">
3084
3085<h5>Syntax:</h5>
3086<pre>
Reid Spencercf669d82005-04-26 20:41:16 +0000[diff] [blame]3087 declare void %llvm.memset(sbyte* &lt;dest&gt;, ubyte &lt;val&gt;,
3088 uint &lt;len&gt;, uint &lt;align&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3089</pre>
3090
3091<h5>Overview:</h5>
3092
3093<p>
3094The '<tt>llvm.memset</tt>' intrinsic fills a block of memory with a particular
3095byte value.
3096</p>
3097
3098<p>
3099Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
3100does not return a value, and takes an extra alignment argument.
3101</p>
3102
3103<h5>Arguments:</h5>
3104
3105<p>
3106The first argument is a pointer to the destination to fill, the second is the
3107byte value to fill it with, the third argument is an (arbitrarily sized) integer
3108argument specifying the number of bytes to fill, and the fourth argument is the
3109known alignment of destination location.
3110</p>
3111
3112<p>
3113If the call to this intrinisic has an alignment value that is not 0 or 1, then
3114the caller guarantees that the size of the copy is a multiple of the alignment
3115and that the destination pointer is aligned to that boundary.
3116</p>
3117
3118<h5>Semantics:</h5>
3119
3120<p>
3121The '<tt>llvm.memset</tt>' intrinsic fills "len" bytes of memory starting at the
3122destination location. If the argument is known to be aligned to some boundary,
3123this can be specified as the fourth argument, otherwise it should be set to 0 or
31241.
3125</p>
3126</div>
3127
3128
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]3129<!-- _______________________________________________________________________ -->
3130<div class="doc_subsubsection">
Alkis Evlogimenos0fa39232004-06-13 01:16:15 +0000[diff] [blame]3131 <a name="i_isunordered">'<tt>llvm.isunordered</tt>' Intrinsic</a>
3132</div>
3133
3134<div class="doc_text">
3135
3136<h5>Syntax:</h5>
3137<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]3138 declare bool %llvm.isunordered(&lt;float or double&gt; Val1, &lt;float or double&gt; Val2)
Alkis Evlogimenos0fa39232004-06-13 01:16:15 +0000[diff] [blame]3139</pre>
3140
3141<h5>Overview:</h5>
3142
3143<p>
3144The '<tt>llvm.isunordered</tt>' intrinsic returns true if either or both of the
3145specified floating point values is a NAN.
3146</p>
3147
3148<h5>Arguments:</h5>
3149
3150<p>
3151The arguments are floating point numbers of the same type.
3152</p>
3153
3154<h5>Semantics:</h5>
3155
3156<p>
3157If either or both of the arguments is a SNAN or QNAN, it returns true, otherwise
3158false.
3159</p>
3160</div>
3161
3162
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]3163<!-- ======================================================================= -->
3164<div class="doc_subsection">
3165 <a name="int_count">Bit Counting Intrinsics</a>
3166</div>
3167
3168<div class="doc_text">
3169<p>
3170LLVM provides intrinsics for a few important bit counting operations.
3171These allow efficient code generation for some algorithms.
3172</p>
3173
3174</div>
3175
3176<!-- _______________________________________________________________________ -->
3177<div class="doc_subsubsection">
3178 <a name="int_ctpop">'<tt>llvm.ctpop</tt>' Intrinsic</a>
3179</div>
3180
3181<div class="doc_text">
3182
3183<h5>Syntax:</h5>
3184<pre>
3185 declare int %llvm.ctpop(int &lt;src&gt;)
3186
3187</pre>
3188
3189<h5>Overview:</h5>
3190
3191<p>
3192The '<tt>llvm.ctpop</tt>' intrinsic counts the number of ones in a variable.
3193</p>
3194
3195<h5>Arguments:</h5>
3196
3197<p>
Andrew Lenharth5be6f132005-05-04 14:58:31 +0000[diff] [blame]3198The only argument is the value to be counted. The argument may be of any integer type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]3199</p>
3200
3201<h5>Semantics:</h5>
3202
3203<p>
3204The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
3205</p>
3206</div>
3207
3208<!-- _______________________________________________________________________ -->
3209<div class="doc_subsubsection">
3210 <a name="int_cttz">'<tt>llvm.cttz</tt>' Intrinsic</a>
3211</div>
3212
3213<div class="doc_text">
3214
3215<h5>Syntax:</h5>
3216<pre>
3217 declare int %llvm.cttz(int &lt;src&gt;)
3218
3219</pre>
3220
3221<h5>Overview:</h5>
3222
3223<p>
3224The '<tt>llvm.cttz</tt>' intrinsic counts the number of trailing zeros.
3225</p>
3226
3227<h5>Arguments:</h5>
3228
3229<p>
Andrew Lenharth5be6f132005-05-04 14:58:31 +0000[diff] [blame]3230The only argument is the value to be counted. The argument may be of any integer type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]3231</p>
3232
3233<h5>Semantics:</h5>
3234
3235<p>
3236The '<tt>llvm.cttz</tt>' intrinsic counts the trailing zeros in a variable. If the src == 0
3237then the result is the size in bits of the type of src.
3238</p>
3239</div>
3240
3241<!-- _______________________________________________________________________ -->
3242<div class="doc_subsubsection">
3243 <a name="int_ctlz">'<tt>llvm.ctlz</tt>' Intrinsic</a>
3244</div>
3245
3246<div class="doc_text">
3247
3248<h5>Syntax:</h5>
3249<pre>
3250 declare int %llvm.ctlz(int &lt;src&gt;)
3251
3252</pre>
3253
3254<h5>Overview:</h5>
3255
3256<p>
3257The '<tt>llvm.ctlz</tt>' intrinsic counts the number of leading zeros in a variable.
3258</p>
3259
3260<h5>Arguments:</h5>
3261
3262<p>
Andrew Lenharth5be6f132005-05-04 14:58:31 +0000[diff] [blame]3263The only argument is the value to be counted. The argument may be of any integer type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]3264</p>
3265
3266<h5>Semantics:</h5>
3267
3268<p>
3269The '<tt>llvm.ctlz</tt>' intrinsic counts the leading zeros in a variable. If the src == 0
3270then the result is the size in bits of the type of src.
3271</p>
3272</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]3273
3274
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3275<!-- ======================================================================= -->
3276<div class="doc_subsection">
3277 <a name="int_debugger">Debugger Intrinsics</a>
3278</div>
3279
3280<div class="doc_text">
3281<p>
3282The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
3283are described in the <a
3284href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
3285Debugging</a> document.
3286</p>
3287</div>
3288
3289
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3290<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3291<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]3292<address>
3293 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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3297
3298 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
3299 <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
3300 Last modified: $Date$
3301</address>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3302</body>
3303</html>