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gerrit-public.fairphone.software / toolchain / llvm-project / c87f3dff517608007e299c7d47698259f30c8cd6 / . / llvm / docs / LangRef.html
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4<head>
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>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]26 <li><a href="#functionstructure">Functions</a></li>
Anton Korobeynikov546ea7e2007-04-29 18:02:48 +0000[diff] [blame]27 <li><a href="#aliasstructure">Aliases</a>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]28 <li><a href="#paramattrs">Parameter Attributes</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]29 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]30 <li><a href="#datalayout">Data Layout</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]31 </ol>
32 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]33 <li><a href="#typesystem">Type System</a>
34 <ol>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]35 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]36 <ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]37 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]38 </ol>
39 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]40 <li><a href="#t_derived">Derived Types</a>
41 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]42 <li><a href="#t_array">Array Type</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]43 <li><a href="#t_function">Function Type</a></li>
44 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]45 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]46 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]47 <li><a href="#t_vector">Vector Type</a></li>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]48 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]49 </ol>
50 </li>
51 </ol>
52 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]53 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]54 <ol>
55 <li><a href="#simpleconstants">Simple Constants</a>
56 <li><a href="#aggregateconstants">Aggregate Constants</a>
57 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
58 <li><a href="#undefvalues">Undefined Values</a>
59 <li><a href="#constantexprs">Constant Expressions</a>
60 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]61 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]62 <li><a href="#othervalues">Other Values</a>
63 <ol>
64 <li><a href="#inlineasm">Inline Assembler Expressions</a>
65 </ol>
66 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]67 <li><a href="#instref">Instruction Reference</a>
68 <ol>
69 <li><a href="#terminators">Terminator Instructions</a>
70 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]71 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
72 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]73 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
74 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]75 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]76 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</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="#binaryops">Binary Operations</a>
80 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]81 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
82 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
83 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]84 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
85 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
86 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]87 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
88 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
89 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]90 </ol>
91 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]92 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
93 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]94 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
95 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
96 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]97 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]98 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]99 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]100 </ol>
101 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]102 <li><a href="#vectorops">Vector Operations</a>
103 <ol>
104 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
105 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
106 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]107 </ol>
108 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]109 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]110 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]111 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
112 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
113 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]114 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
115 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
116 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]117 </ol>
118 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]119 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]120 <ol>
121 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
122 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
123 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
124 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
125 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]126 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
127 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
128 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
129 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]130 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
131 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]132 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]133 </ol>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]134 <li><a href="#otherops">Other Operations</a>
135 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]136 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
137 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]138 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]139 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]140 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]141 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]142 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]143 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]144 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]145 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]146 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]147 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]148 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
149 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]150 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
151 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
152 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]153 </ol>
154 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]155 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
156 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]157 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
158 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
159 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]160 </ol>
161 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]162 <li><a href="#int_codegen">Code Generator Intrinsics</a>
163 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]164 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
165 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
166 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
167 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
168 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
169 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
170 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]171 </ol>
172 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]173 <li><a href="#int_libc">Standard C Library Intrinsics</a>
174 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]175 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
176 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
177 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
178 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
179 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]180 </ol>
181 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]182 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]183 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]184 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]185 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
186 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
187 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]188 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
189 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]190 </ol>
191 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]192 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]193 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]194 </ol>
195 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]196</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]197
198<div class="doc_author">
199 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
200 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]201</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]202
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]203<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]204<div class="doc_section"> <a name="abstract">Abstract </a></div>
205<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]206
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]207<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]208<p>This document is a reference manual for the LLVM assembly language.
209LLVM is an SSA based representation that provides type safety,
210low-level operations, flexibility, and the capability of representing
211'all' high-level languages cleanly. It is the common code
212representation used throughout all phases of the LLVM compilation
213strategy.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]214</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]215
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]216<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]217<div class="doc_section"> <a name="introduction">Introduction</a> </div>
218<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]219
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]220<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]221
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]222<p>The LLVM code representation is designed to be used in three
223different forms: as an in-memory compiler IR, as an on-disk bytecode
224representation (suitable for fast loading by a Just-In-Time compiler),
225and as a human readable assembly language representation. This allows
226LLVM to provide a powerful intermediate representation for efficient
227compiler transformations and analysis, while providing a natural means
228to debug and visualize the transformations. The three different forms
229of LLVM are all equivalent. This document describes the human readable
230representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]231
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]232<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]233while being expressive, typed, and extensible at the same time. It
234aims to be a "universal IR" of sorts, by being at a low enough level
235that high-level ideas may be cleanly mapped to it (similar to how
236microprocessors are "universal IR's", allowing many source languages to
237be mapped to them). By providing type information, LLVM can be used as
238the target of optimizations: for example, through pointer analysis, it
239can be proven that a C automatic variable is never accessed outside of
240the current function... allowing it to be promoted to a simple SSA
241value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]242
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]243</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]244
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]245<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]246<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]247
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]248<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]249
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]250<p>It is important to note that this document describes 'well formed'
251LLVM assembly language. There is a difference between what the parser
252accepts and what is considered 'well formed'. For example, the
253following instruction is syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]254
255<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]256 %x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]257</pre>
258
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]259<p>...because the definition of <tt>%x</tt> does not dominate all of
260its uses. The LLVM infrastructure provides a verification pass that may
261be used to verify that an LLVM module is well formed. This pass is
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]262automatically run by the parser after parsing input assembly and by
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]263the optimizer before it outputs bytecode. The violations pointed out
264by the verifier pass indicate bugs in transformation passes or input to
265the parser.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]266
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]267<!-- Describe the typesetting conventions here. --> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]268
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]269<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]270<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]271<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]272
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]273<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]274
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]275<p>LLVM uses three different forms of identifiers, for different
276purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]277
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]278<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]279 <li>Named values are represented as a string of characters with a '%' prefix.
280 For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
281 regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
282 Identifiers which require other characters in their names can be surrounded
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]283 with quotes. In this way, anything except a <tt>&quot;</tt> character can be used
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]284 in a name.</li>
285
286 <li>Unnamed values are represented as an unsigned numeric value with a '%'
287 prefix. For example, %12, %2, %44.</li>
288
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]289 <li>Constants, which are described in a <a href="#constants">section about
290 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]291</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]292
293<p>LLVM requires that values start with a '%' sign for two reasons: Compilers
294don't need to worry about name clashes with reserved words, and the set of
295reserved words may be expanded in the future without penalty. Additionally,
296unnamed identifiers allow a compiler to quickly come up with a temporary
297variable without having to avoid symbol table conflicts.</p>
298
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]299<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]300languages. There are keywords for different opcodes
301('<tt><a href="#i_add">add</a></tt>',
302 '<tt><a href="#i_bitcast">bitcast</a></tt>',
303 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]304href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]305and others. These reserved words cannot conflict with variable names, because
306none of them start with a '%' character.</p>
307
308<p>Here is an example of LLVM code to multiply the integer variable
309'<tt>%X</tt>' by 8:</p>
310
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]311<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]312
313<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]314 %result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]315</pre>
316
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]317<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]318
319<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]320 %result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]321</pre>
322
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]323<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]324
325<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]326 <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
327 <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
328 %result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]329</pre>
330
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]331<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
332important lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]333
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]334<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]335
336 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
337 line.</li>
338
339 <li>Unnamed temporaries are created when the result of a computation is not
340 assigned to a named value.</li>
341
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]342 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]343
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]344</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]345
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]346<p>...and it also shows a convention that we follow in this document. When
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]347demonstrating instructions, we will follow an instruction with a comment that
348defines the type and name of value produced. Comments are shown in italic
349text.</p>
350
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]351</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]352
353<!-- *********************************************************************** -->
354<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
355<!-- *********************************************************************** -->
356
357<!-- ======================================================================= -->
358<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
359</div>
360
361<div class="doc_text">
362
363<p>LLVM programs are composed of "Module"s, each of which is a
364translation unit of the input programs. Each module consists of
365functions, global variables, and symbol table entries. Modules may be
366combined together with the LLVM linker, which merges function (and
367global variable) definitions, resolves forward declarations, and merges
368symbol table entries. Here is an example of the "hello world" module:</p>
369
370<pre><i>; Declare the string constant as a global constant...</i>
371<a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]372 href="#globalvars">constant</a> <a href="#t_array">[13 x i8 ]</a> c"hello world\0A\00" <i>; [13 x i8 ]*</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]373
374<i>; External declaration of the puts function</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]375<a href="#functionstructure">declare</a> i32 %puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]376
377<i>; Definition of main function</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]378define i32 %main() { <i>; i32()* </i>
379 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]380 %cast210 = <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]381 href="#i_getelementptr">getelementptr</a> [13 x i8 ]* %.LC0, i64 0, i64 0 <i>; i8 *</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]382
383 <i>; Call puts function to write out the string to stdout...</i>
384 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]385 href="#i_call">call</a> i32 %puts(i8 * %cast210) <i>; i32</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]386 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]387 href="#i_ret">ret</a> i32 0<br>}<br></pre>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]388
389<p>This example is made up of a <a href="#globalvars">global variable</a>
390named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
391function, and a <a href="#functionstructure">function definition</a>
392for "<tt>main</tt>".</p>
393
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]394<p>In general, a module is made up of a list of global values,
395where both functions and global variables are global values. Global values are
396represented by a pointer to a memory location (in this case, a pointer to an
397array of char, and a pointer to a function), and have one of the following <a
398href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]399
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]400</div>
401
402<!-- ======================================================================= -->
403<div class="doc_subsection">
404 <a name="linkage">Linkage Types</a>
405</div>
406
407<div class="doc_text">
408
409<p>
410All Global Variables and Functions have one of the following types of linkage:
411</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]412
413<dl>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]414
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]415 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]416
417 <dd>Global values with internal linkage are only directly accessible by
418 objects in the current module. In particular, linking code into a module with
419 an internal global value may cause the internal to be renamed as necessary to
420 avoid collisions. Because the symbol is internal to the module, all
421 references can be updated. This corresponds to the notion of the
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]422 '<tt>static</tt>' keyword in C.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]423 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]424
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]425 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]426
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]427 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
428 the same name when linkage occurs. This is typically used to implement
429 inline functions, templates, or other code which must be generated in each
430 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
431 allowed to be discarded.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]432 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]433
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]434 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]435
436 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
437 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]438 used for globals that may be emitted in multiple translation units, but that
439 are not guaranteed to be emitted into every translation unit that uses them.
440 One example of this are common globals in C, such as "<tt>int X;</tt>" at
441 global scope.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]442 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]443
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]444 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]445
446 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
447 pointer to array type. When two global variables with appending linkage are
448 linked together, the two global arrays are appended together. This is the
449 LLVM, typesafe, equivalent of having the system linker append together
450 "sections" with identical names when .o files are linked.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]451 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]452
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]453 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
454 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
455 until linked, if not linked, the symbol becomes null instead of being an
456 undefined reference.
457 </dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]458
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]459 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]460
461 <dd>If none of the above identifiers are used, the global is externally
462 visible, meaning that it participates in linkage and can be used to resolve
463 external symbol references.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]464 </dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]465</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]466
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]467 <p>
468 The next two types of linkage are targeted for Microsoft Windows platform
469 only. They are designed to support importing (exporting) symbols from (to)
470 DLLs.
471 </p>
472
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]473 <dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]474 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
475
476 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
477 or variable via a global pointer to a pointer that is set up by the DLL
478 exporting the symbol. On Microsoft Windows targets, the pointer name is
479 formed by combining <code>_imp__</code> and the function or variable name.
480 </dd>
481
482 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
483
484 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
485 pointer to a pointer in a DLL, so that it can be referenced with the
486 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
487 name is formed by combining <code>_imp__</code> and the function or variable
488 name.
489 </dd>
490
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]491</dl>
492
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]493<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]494variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
495variable and was linked with this one, one of the two would be renamed,
496preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
497external (i.e., lacking any linkage declarations), they are accessible
Reid Spencer92c671e2007-01-05 00:59:10 +0000[diff] [blame]498outside of the current module.</p>
499<p>It is illegal for a function <i>declaration</i>
500to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]501or <tt>extern_weak</tt>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]502<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
503linkages.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]504</div>
505
506<!-- ======================================================================= -->
507<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]508 <a name="callingconv">Calling Conventions</a>
509</div>
510
511<div class="doc_text">
512
513<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
514and <a href="#i_invoke">invokes</a> can all have an optional calling convention
515specified for the call. The calling convention of any pair of dynamic
516caller/callee must match, or the behavior of the program is undefined. The
517following calling conventions are supported by LLVM, and more may be added in
518the future:</p>
519
520<dl>
521 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
522
523 <dd>This calling convention (the default if no other calling convention is
524 specified) matches the target C calling conventions. This calling convention
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]525 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencer72ba4992006-12-31 21:30:18 +0000[diff] [blame]526 prototype and implemented declaration of the function (as does normal C).
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]527 </dd>
528
529 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
530
531 <dd>This calling convention attempts to make calls as fast as possible
532 (e.g. by passing things in registers). This calling convention allows the
533 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattnerc792eb32005-05-06 23:08:23 +0000[diff] [blame]534 without having to conform to an externally specified ABI. Implementations of
535 this convention should allow arbitrary tail call optimization to be supported.
536 This calling convention does not support varargs and requires the prototype of
537 all callees to exactly match the prototype of the function definition.
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]538 </dd>
539
540 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
541
542 <dd>This calling convention attempts to make code in the caller as efficient
543 as possible under the assumption that the call is not commonly executed. As
544 such, these calls often preserve all registers so that the call does not break
545 any live ranges in the caller side. This calling convention does not support
546 varargs and requires the prototype of all callees to exactly match the
547 prototype of the function definition.
548 </dd>
549
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]550 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]551
552 <dd>Any calling convention may be specified by number, allowing
553 target-specific calling conventions to be used. Target specific calling
554 conventions start at 64.
555 </dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]556</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]557
558<p>More calling conventions can be added/defined on an as-needed basis, to
559support pascal conventions or any other well-known target-independent
560convention.</p>
561
562</div>
563
564<!-- ======================================================================= -->
565<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]566 <a name="visibility">Visibility Styles</a>
567</div>
568
569<div class="doc_text">
570
571<p>
572All Global Variables and Functions have one of the following visibility styles:
573</p>
574
575<dl>
576 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
577
578 <dd>On ELF, default visibility means that the declaration is visible to other
579 modules and, in shared libraries, means that the declared entity may be
580 overridden. On Darwin, default visibility means that the declaration is
581 visible to other modules. Default visibility corresponds to "external
582 linkage" in the language.
583 </dd>
584
585 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
586
587 <dd>Two declarations of an object with hidden visibility refer to the same
588 object if they are in the same shared object. Usually, hidden visibility
589 indicates that the symbol will not be placed into the dynamic symbol table,
590 so no other module (executable or shared library) can reference it
591 directly.
592 </dd>
593
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]594 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
595
596 <dd>On ELF, protected visibility indicates that the symbol will be placed in
597 the dynamic symbol table, but that references within the defining module will
598 bind to the local symbol. That is, the symbol cannot be overridden by another
599 module.
600 </dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]601</dl>
602
603</div>
604
605<!-- ======================================================================= -->
606<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]607 <a name="globalvars">Global Variables</a>
608</div>
609
610<div class="doc_text">
611
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]612<p>Global variables define regions of memory allocated at compilation time
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]613instead of run-time. Global variables may optionally be initialized, may have
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]614an explicit section to be placed in, and may have an optional explicit alignment
615specified. A variable may be defined as "thread_local", which means that it
616will not be shared by threads (each thread will have a separated copy of the
617variable). A variable may be defined as a global "constant," which indicates
618that the contents of the variable will <b>never</b> be modified (enabling better
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]619optimization, allowing the global data to be placed in the read-only section of
620an executable, etc). Note that variables that need runtime initialization
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]621cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]622
623<p>
624LLVM explicitly allows <em>declarations</em> of global variables to be marked
625constant, even if the final definition of the global is not. This capability
626can be used to enable slightly better optimization of the program, but requires
627the language definition to guarantee that optimizations based on the
628'constantness' are valid for the translation units that do not include the
629definition.
630</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]631
632<p>As SSA values, global variables define pointer values that are in
633scope (i.e. they dominate) all basic blocks in the program. Global
634variables always define a pointer to their "content" type because they
635describe a region of memory, and all memory objects in LLVM are
636accessed through pointers.</p>
637
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]638<p>LLVM allows an explicit section to be specified for globals. If the target
639supports it, it will emit globals to the section specified.</p>
640
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]641<p>An explicit alignment may be specified for a global. If not present, or if
642the alignment is set to zero, the alignment of the global is set by the target
643to whatever it feels convenient. If an explicit alignment is specified, the
644global is forced to have at least that much alignment. All alignments must be
645a power of 2.</p>
646
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]647<p>For example, the following defines a global with an initializer, section,
648 and alignment:</p>
649
650<pre>
651 %G = constant float 1.0, section "foo", align 4
652</pre>
653
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]654</div>
655
656
657<!-- ======================================================================= -->
658<div class="doc_subsection">
659 <a name="functionstructure">Functions</a>
660</div>
661
662<div class="doc_text">
663
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]664<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
665an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]666<a href="#visibility">visibility style</a>, an optional
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]667<a href="#callingconv">calling convention</a>, a return type, an optional
668<a href="#paramattrs">parameter attribute</a> for the return type, a function
669name, a (possibly empty) argument list (each with optional
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]670<a href="#paramattrs">parameter attributes</a>), an optional section, an
671optional alignment, an opening curly brace, a list of basic blocks, and a
672closing curly brace.
673
674LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
675optional <a href="#linkage">linkage type</a>, an optional
676<a href="#visibility">visibility style</a>, an optional
677<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]678<a href="#paramattrs">parameter attribute</a> for the return type, a function
679name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]680
681<p>A function definition contains a list of basic blocks, forming the CFG for
682the function. Each basic block may optionally start with a label (giving the
683basic block a symbol table entry), contains a list of instructions, and ends
684with a <a href="#terminators">terminator</a> instruction (such as a branch or
685function return).</p>
686
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]687<p>The first basic block in a program is special in two ways: it is immediately
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]688executed on entrance to the function, and it is not allowed to have predecessor
689basic blocks (i.e. there can not be any branches to the entry block of a
690function). Because the block can have no predecessors, it also cannot have any
691<a href="#i_phi">PHI nodes</a>.</p>
692
693<p>LLVM functions are identified by their name and type signature. Hence, two
694functions with the same name but different parameter lists or return values are
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]695considered different functions, and LLVM will resolve references to each
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]696appropriately.</p>
697
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]698<p>LLVM allows an explicit section to be specified for functions. If the target
699supports it, it will emit functions to the section specified.</p>
700
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]701<p>An explicit alignment may be specified for a function. If not present, or if
702the alignment is set to zero, the alignment of the function is set by the target
703to whatever it feels convenient. If an explicit alignment is specified, the
704function is forced to have at least that much alignment. All alignments must be
705a power of 2.</p>
706
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]707</div>
708
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]709
710<!-- ======================================================================= -->
711<div class="doc_subsection">
712 <a name="aliasstructure">Aliases</a>
713</div>
714<div class="doc_text">
715 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikovb18f8f82007-04-28 13:45:00 +0000[diff] [blame]716 function or global variable or bitcast of global value). Aliases may have an
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]717 optional <a href="#linkage">linkage type</a>, and an
718 optional <a href="#visibility">visibility style</a>.</p>
719
720 <h5>Syntax:</h5>
721
722 <pre>
723 @&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
724 </pre>
725
726</div>
727
728
729
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]730<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]731<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
732<div class="doc_text">
733 <p>The return type and each parameter of a function type may have a set of
734 <i>parameter attributes</i> associated with them. Parameter attributes are
735 used to communicate additional information about the result or parameters of
736 a function. Parameter attributes are considered to be part of the function
737 type so two functions types that differ only by the parameter attributes
738 are different function types.</p>
739
Reid Spencercf7ebf52007-01-15 18:27:39 +0000[diff] [blame]740 <p>Parameter attributes are simple keywords that follow the type specified. If
741 multiple parameter attributes are needed, they are space separated. For
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]742 example:</p><pre>
Reid Spencercf7ebf52007-01-15 18:27:39 +0000[diff] [blame]743 %someFunc = i16 (i8 sext %someParam) zext
744 %someFunc = i16 (i8 zext %someParam) zext</pre>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]745 <p>Note that the two function types above are unique because the parameter has
Reid Spencercf7ebf52007-01-15 18:27:39 +0000[diff] [blame]746 a different attribute (sext in the first one, zext in the second). Also note
747 that the attribute for the function result (zext) comes immediately after the
748 argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]749
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]750 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]751 <dl>
Reid Spencercf7ebf52007-01-15 18:27:39 +0000[diff] [blame]752 <dt><tt>zext</tt></dt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]753 <dd>This indicates that the parameter should be zero extended just before
754 a call to this function.</dd>
Reid Spencercf7ebf52007-01-15 18:27:39 +0000[diff] [blame]755 <dt><tt>sext</tt></dt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]756 <dd>This indicates that the parameter should be sign extended just before
757 a call to this function.</dd>
Anton Korobeynikove8166852007-01-28 14:30:45 +0000[diff] [blame]758 <dt><tt>inreg</tt></dt>
759 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikove93c6e82007-01-28 15:27:21 +0000[diff] [blame]760 possible) during assembling function call. Support for this attribute is
761 target-specific</dd>
Anton Korobeynikove8166852007-01-28 14:30:45 +0000[diff] [blame]762 <dt><tt>sret</tt></dt>
Anton Korobeynikove93c6e82007-01-28 15:27:21 +0000[diff] [blame]763 <dd>This indicates that the parameter specifies the address of a structure
Reid Spencer05dbb9d2007-03-22 02:02:11 +0000[diff] [blame]764 that is the return value of the function in the source program.</dd>
Reid Spencer9d1700e2007-03-22 02:18:56 +0000[diff] [blame]765 <dt><tt>noreturn</tt></dt>
766 <dd>This function attribute indicates that the function never returns. This
767 indicates to LLVM that every call to this function should be treated as if
768 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Reid Spencer05dbb9d2007-03-22 02:02:11 +0000[diff] [blame]769 <dt><tt>nounwind</tt></dt>
770 <dd>This function attribute indicates that the function type does not use
771 the unwind instruction and does not allow stack unwinding to propagate
772 through it.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]773 </dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]774
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]775</div>
776
777<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]778<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]779 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]780</div>
781
782<div class="doc_text">
783<p>
784Modules may contain "module-level inline asm" blocks, which corresponds to the
785GCC "file scope inline asm" blocks. These blocks are internally concatenated by
786LLVM and treated as a single unit, but may be separated in the .ll file if
787desired. The syntax is very simple:
788</p>
789
790<div class="doc_code"><pre>
Chris Lattnera1280ad2006-01-24 00:37:20 +0000[diff] [blame]791 module asm "inline asm code goes here"
792 module asm "more can go here"
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]793</pre></div>
794
795<p>The strings can contain any character by escaping non-printable characters.
796 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
797 for the number.
798</p>
799
800<p>
801 The inline asm code is simply printed to the machine code .s file when
802 assembly code is generated.
803</p>
804</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]805
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]806<!-- ======================================================================= -->
807<div class="doc_subsection">
808 <a name="datalayout">Data Layout</a>
809</div>
810
811<div class="doc_text">
812<p>A module may specify a target specific data layout string that specifies how
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]813data is to be laid out in memory. The syntax for the data layout is simply:</p>
814<pre> target datalayout = "<i>layout specification</i>"</pre>
815<p>The <i>layout specification</i> consists of a list of specifications
816separated by the minus sign character ('-'). Each specification starts with a
817letter and may include other information after the letter to define some
818aspect of the data layout. The specifications accepted are as follows: </p>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]819<dl>
820 <dt><tt>E</tt></dt>
821 <dd>Specifies that the target lays out data in big-endian form. That is, the
822 bits with the most significance have the lowest address location.</dd>
823 <dt><tt>e</tt></dt>
824 <dd>Specifies that hte target lays out data in little-endian form. That is,
825 the bits with the least significance have the lowest address location.</dd>
826 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
827 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
828 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
829 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
830 too.</dd>
831 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
832 <dd>This specifies the alignment for an integer type of a given bit
833 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
834 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
835 <dd>This specifies the alignment for a vector type of a given bit
836 <i>size</i>.</dd>
837 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
838 <dd>This specifies the alignment for a floating point type of a given bit
839 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
840 (double).</dd>
841 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
842 <dd>This specifies the alignment for an aggregate type of a given bit
843 <i>size</i>.</dd>
844</dl>
845<p>When constructing the data layout for a given target, LLVM starts with a
846default set of specifications which are then (possibly) overriden by the
847specifications in the <tt>datalayout</tt> keyword. The default specifications
848are given in this list:</p>
849<ul>
850 <li><tt>E</tt> - big endian</li>
851 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
852 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
853 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
854 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
855 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
856 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
857 alignment of 64-bits</li>
858 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
859 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
860 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
861 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
862 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
863</ul>
864<p>When llvm is determining the alignment for a given type, it uses the
865following rules:
866<ol>
867 <li>If the type sought is an exact match for one of the specifications, that
868 specification is used.</li>
869 <li>If no match is found, and the type sought is an integer type, then the
870 smallest integer type that is larger than the bitwidth of the sought type is
871 used. If none of the specifications are larger than the bitwidth then the the
872 largest integer type is used. For example, given the default specifications
873 above, the i7 type will use the alignment of i8 (next largest) while both
874 i65 and i256 will use the alignment of i64 (largest specified).</li>
875 <li>If no match is found, and the type sought is a vector type, then the
876 largest vector type that is smaller than the sought vector type will be used
877 as a fall back. This happens because <128 x double> can be implemented in
878 terms of 64 <2 x double>, for example.</li>
879</ol>
880</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]881
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]882<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]883<div class="doc_section"> <a name="typesystem">Type System</a> </div>
884<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]885
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]886<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]887
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]888<p>The LLVM type system is one of the most important features of the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]889intermediate representation. Being typed enables a number of
890optimizations to be performed on the IR directly, without having to do
891extra analyses on the side before the transformation. A strong type
892system makes it easier to read the generated code and enables novel
893analyses and transformations that are not feasible to perform on normal
894three address code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]895
896</div>
897
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]898<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]899<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]900<div class="doc_text">
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]901<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]902system. The current set of primitive types is as follows:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]903
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]904<table class="layout">
905 <tr class="layout">
906 <td class="left">
907 <table>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]908 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]909 <tr><th>Type</th><th>Description</th></tr>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]910 <tr><td><tt><a name="t_void">void</a></tt></td><td>No value</td></tr>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]911 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]912 </tbody>
913 </table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]914 </td>
915 <td class="right">
916 <table>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]917 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]918 <tr><th>Type</th><th>Description</th></tr>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]919 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]920 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]921 </tbody>
922 </table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]923 </td>
924 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]925</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]926</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]927
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]928<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]929<div class="doc_subsubsection"> <a name="t_classifications">Type
930Classifications</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]931<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]932<p>These different primitive types fall into a few useful
933classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]934
935<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]936 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]937 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]938 <tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]939 <td><a name="t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]940 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]941 </tr>
942 <tr>
943 <td><a name="t_floating">floating point</a></td>
944 <td><tt>float, double</tt></td>
945 </tr>
946 <tr>
947 <td><a name="t_firstclass">first class</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]948 <td><tt>i1, ..., float, double, <br/>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]949 <a href="#t_pointer">pointer</a>,<a href="#t_vector">vector</a></tt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]950 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]951 </tr>
952 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]953</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]954
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]955<p>The <a href="#t_firstclass">first class</a> types are perhaps the
956most important. Values of these types are the only ones which can be
957produced by instructions, passed as arguments, or used as operands to
958instructions. This means that all structures and arrays must be
959manipulated either by pointer or by component.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]960</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]961
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]962<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]963<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]964
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]965<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]966
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]967<p>The real power in LLVM comes from the derived types in the system.
968This is what allows a programmer to represent arrays, functions,
969pointers, and other useful types. Note that these derived types may be
970recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]971
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]972</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]973
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]974<!-- _______________________________________________________________________ -->
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]975<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
976
977<div class="doc_text">
978
979<h5>Overview:</h5>
980<p>The integer type is a very simple derived type that simply specifies an
981arbitrary bit width for the integer type desired. Any bit width from 1 bit to
9822^23-1 (about 8 million) can be specified.</p>
983
984<h5>Syntax:</h5>
985
986<pre>
987 iN
988</pre>
989
990<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
991value.</p>
992
993<h5>Examples:</h5>
994<table class="layout">
995 <tr class="layout">
996 <td class="left">
997 <tt>i1</tt><br/>
998 <tt>i4</tt><br/>
999 <tt>i8</tt><br/>
1000 <tt>i16</tt><br/>
1001 <tt>i32</tt><br/>
1002 <tt>i42</tt><br/>
1003 <tt>i64</tt><br/>
1004 <tt>i1942652</tt><br/>
1005 </td>
1006 <td class="left">
1007 A boolean integer of 1 bit<br/>
1008 A nibble sized integer of 4 bits.<br/>
1009 A byte sized integer of 8 bits.<br/>
1010 A half word sized integer of 16 bits.<br/>
1011 A word sized integer of 32 bits.<br/>
1012 An integer whose bit width is the answer. <br/>
1013 A double word sized integer of 64 bits.<br/>
1014 A really big integer of over 1 million bits.<br/>
1015 </td>
1016 </tr>
1017</table>
1018
1019<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1020<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1021
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1022<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1023
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1024<h5>Overview:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1025
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1026<p>The array type is a very simple derived type that arranges elements
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1027sequentially in memory. The array type requires a size (number of
1028elements) and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1029
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1030<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1031
1032<pre>
1033 [&lt;# elements&gt; x &lt;elementtype&gt;]
1034</pre>
1035
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1036<p>The number of elements is a constant integer value; elementtype may
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1037be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1038
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1039<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1040<table class="layout">
1041 <tr class="layout">
1042 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1043 <tt>[40 x i32 ]</tt><br/>
1044 <tt>[41 x i32 ]</tt><br/>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1045 <tt>[40 x i8]</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1046 </td>
1047 <td class="left">
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1048 Array of 40 32-bit integer values.<br/>
1049 Array of 41 32-bit integer values.<br/>
1050 Array of 40 8-bit integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1051 </td>
1052 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1053</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1054<p>Here are some examples of multidimensional arrays:</p>
1055<table class="layout">
1056 <tr class="layout">
1057 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1058 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1059 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1060 <tt>[2 x [3 x [4 x i16]]]</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1061 </td>
1062 <td class="left">
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1063 3x4 array of 32-bit integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1064 12x10 array of single precision floating point values.<br/>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1065 2x3x4 array of 16-bit integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1066 </td>
1067 </tr>
1068</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1069
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1070<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1071length array. Normally, accesses past the end of an array are undefined in
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1072LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1073As a special case, however, zero length arrays are recognized to be variable
1074length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1075type "{ i32, [0 x float]}", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1076
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1077</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1078
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1079<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1080<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1081<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1082<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1083<p>The function type can be thought of as a function signature. It
1084consists of a return type and a list of formal parameter types.
John Criswella0d50d22003-11-25 21:45:46 +0000[diff] [blame]1085Function types are usually used to build virtual function tables
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1086(which are structures of pointers to functions), for indirect function
1087calls, and when defining a function.</p>
John Criswella0d50d22003-11-25 21:45:46 +0000[diff] [blame]1088<p>
1089The return type of a function type cannot be an aggregate type.
1090</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1091<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1092<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1093<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Misha Brukman20f9a622004-08-12 20:16:08 +0000[diff] [blame]1094specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1095which indicates that the function takes a variable number of arguments.
1096Variable argument functions can access their arguments with the <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1097 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1098<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1099<table class="layout">
1100 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1101 <td class="left"><tt>i32 (i32)</tt></td>
1102 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1103 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1104 </tr><tr class="layout">
Reid Spencere6a338d2007-01-15 18:28:34 +0000[diff] [blame]1105 <td class="left"><tt>float&nbsp;(i16&nbsp;sext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1106 </tt></td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1107 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1108 an <tt>i16</tt> that should be sign extended and a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1109 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1110 <tt>float</tt>.
1111 </td>
1112 </tr><tr class="layout">
1113 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1114 <td class="left">A vararg function that takes at least one
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1115 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1116 which returns an integer. This is the signature for <tt>printf</tt> in
1117 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1118 </td>
1119 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1120</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1121
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1122</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1123<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1124<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1125<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1126<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1127<p>The structure type is used to represent a collection of data members
1128together in memory. The packing of the field types is defined to match
1129the ABI of the underlying processor. The elements of a structure may
1130be any type that has a size.</p>
1131<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1132and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1133field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1134instruction.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1135<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1136<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1137<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1138<table class="layout">
1139 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1140 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1141 <td class="left">A triple of three <tt>i32</tt> values</td>
1142 </tr><tr class="layout">
1143 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1144 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1145 second element is a <a href="#t_pointer">pointer</a> to a
1146 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1147 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1148 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1149</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1150</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1151
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1152<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1153<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1154</div>
1155<div class="doc_text">
1156<h5>Overview:</h5>
1157<p>The packed structure type is used to represent a collection of data members
1158together in memory. There is no padding between fields. Further, the alignment
1159of a packed structure is 1 byte. The elements of a packed structure may
1160be any type that has a size.</p>
1161<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1162and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1163field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1164instruction.</p>
1165<h5>Syntax:</h5>
1166<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1167<h5>Examples:</h5>
1168<table class="layout">
1169 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1170 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1171 <td class="left">A triple of three <tt>i32</tt> values</td>
1172 </tr><tr class="layout">
1173 <td class="left"><tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}&nbsp;&gt;</tt></td>
1174 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1175 second element is a <a href="#t_pointer">pointer</a> to a
1176 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1177 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1178 </tr>
1179</table>
1180</div>
1181
1182<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1183<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1184<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1185<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1186<p>As in many languages, the pointer type represents a pointer or
1187reference to another object, which must live in memory.</p>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1188<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1189<pre> &lt;type&gt; *<br></pre>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1190<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1191<table class="layout">
1192 <tr class="layout">
1193 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1194 <tt>[4x i32]*</tt><br/>
1195 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1196 </td>
1197 <td class="left">
1198 A <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1199 four <tt>i32</tt> values<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1200 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1201 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1202 <tt>i32</tt>.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1203 </td>
1204 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1205</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1206</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1207
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1208<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1209<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1210<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1211
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1212<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1213
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1214<p>A vector type is a simple derived type that represents a vector
1215of elements. Vector types are used when multiple primitive data
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1216are operated in parallel using a single instruction (SIMD).
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1217A vector type requires a size (number of
Chris Lattner330ce692005-11-10 01:44:22 +0000[diff] [blame]1218elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1219of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1220considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1221
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1222<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1223
1224<pre>
1225 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1226</pre>
1227
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1228<p>The number of elements is a constant integer value; elementtype may
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1229be any integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1230
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1231<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1232
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1233<table class="layout">
1234 <tr class="layout">
1235 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1236 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1237 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1238 <tt>&lt;2 x i64&gt;</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1239 </td>
1240 <td class="left">
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1241 Vector of 4 32-bit integer values.<br/>
1242 Vector of 8 floating-point values.<br/>
1243 Vector of 2 64-bit integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1244 </td>
1245 </tr>
1246</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1247</div>
1248
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1249<!-- _______________________________________________________________________ -->
1250<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1251<div class="doc_text">
1252
1253<h5>Overview:</h5>
1254
1255<p>Opaque types are used to represent unknown types in the system. This
1256corresponds (for example) to the C notion of a foward declared structure type.
1257In LLVM, opaque types can eventually be resolved to any type (not just a
1258structure type).</p>
1259
1260<h5>Syntax:</h5>
1261
1262<pre>
1263 opaque
1264</pre>
1265
1266<h5>Examples:</h5>
1267
1268<table class="layout">
1269 <tr class="layout">
1270 <td class="left">
1271 <tt>opaque</tt>
1272 </td>
1273 <td class="left">
1274 An opaque type.<br/>
1275 </td>
1276 </tr>
1277</table>
1278</div>
1279
1280
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1281<!-- *********************************************************************** -->
1282<div class="doc_section"> <a name="constants">Constants</a> </div>
1283<!-- *********************************************************************** -->
1284
1285<div class="doc_text">
1286
1287<p>LLVM has several different basic types of constants. This section describes
1288them all and their syntax.</p>
1289
1290</div>
1291
1292<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1293<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1294
1295<div class="doc_text">
1296
1297<dl>
1298 <dt><b>Boolean constants</b></dt>
1299
1300 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1301 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1302 </dd>
1303
1304 <dt><b>Integer constants</b></dt>
1305
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1306 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1307 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1308 integer types.
1309 </dd>
1310
1311 <dt><b>Floating point constants</b></dt>
1312
1313 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1314 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1315 notation (see below). Floating point constants must have a <a
1316 href="#t_floating">floating point</a> type. </dd>
1317
1318 <dt><b>Null pointer constants</b></dt>
1319
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1320 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1321 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1322
1323</dl>
1324
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1325<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1326of floating point constants. For example, the form '<tt>double
13270x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
13284.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1329(and the only time that they are generated by the disassembler) is when a
1330floating point constant must be emitted but it cannot be represented as a
1331decimal floating point number. For example, NaN's, infinities, and other
1332special values are represented in their IEEE hexadecimal format so that
1333assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1334
1335</div>
1336
1337<!-- ======================================================================= -->
1338<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1339</div>
1340
1341<div class="doc_text">
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]1342<p>Aggregate constants arise from aggregation of simple constants
1343and smaller aggregate constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1344
1345<dl>
1346 <dt><b>Structure constants</b></dt>
1347
1348 <dd>Structure constants are represented with notation similar to structure
1349 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1350 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
1351 where "<tt>%G</tt>" is declared as "<tt>%G = external global i32</tt>". Structure constants
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]1352 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1353 types of elements must match those specified by the type.
1354 </dd>
1355
1356 <dt><b>Array constants</b></dt>
1357
1358 <dd>Array constants are represented with notation similar to array type
1359 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1360 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1361 constants must have <a href="#t_array">array type</a>, and the number and
1362 types of elements must match those specified by the type.
1363 </dd>
1364
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1365 <dt><b>Vector constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1366
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1367 <dd>Vector constants are represented with notation similar to vector type
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1368 definitions (a comma separated list of elements, surrounded by
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1369 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1370 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1371 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1372 match those specified by the type.
1373 </dd>
1374
1375 <dt><b>Zero initialization</b></dt>
1376
1377 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1378 value to zero of <em>any</em> type, including scalar and aggregate types.
1379 This is often used to avoid having to print large zero initializers (e.g. for
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1380 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1381 initializers.
1382 </dd>
1383</dl>
1384
1385</div>
1386
1387<!-- ======================================================================= -->
1388<div class="doc_subsection">
1389 <a name="globalconstants">Global Variable and Function Addresses</a>
1390</div>
1391
1392<div class="doc_text">
1393
1394<p>The addresses of <a href="#globalvars">global variables</a> and <a
1395href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1396constants. These constants are explicitly referenced when the <a
1397href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1398href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1399file:</p>
1400
1401<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1402 %X = global i32 17
1403 %Y = global i32 42
1404 %Z = global [2 x i32*] [ i32* %X, i32* %Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1405</pre>
1406
1407</div>
1408
1409<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1410<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1411<div class="doc_text">
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1412 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1413 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1414 a constant is permitted.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1415
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1416 <p>Undefined values indicate to the compiler that the program is well defined
1417 no matter what value is used, giving the compiler more freedom to optimize.
1418 </p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1419</div>
1420
1421<!-- ======================================================================= -->
1422<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1423</div>
1424
1425<div class="doc_text">
1426
1427<p>Constant expressions are used to allow expressions involving other constants
1428to be used as constants. Constant expressions may be of any <a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1429href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1430that does not have side effects (e.g. load and call are not supported). The
1431following is the syntax for constant expressions:</p>
1432
1433<dl>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1434 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1435 <dd>Truncate a constant to another type. The bit size of CST must be larger
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1436 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1437
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1438 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1439 <dd>Zero extend a constant to another type. The bit size of CST must be
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1440 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1441
1442 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1443 <dd>Sign extend a constant to another type. The bit size of CST must be
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1444 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1445
1446 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1447 <dd>Truncate a floating point constant to another floating point type. The
1448 size of CST must be larger than the size of TYPE. Both types must be
1449 floating point.</dd>
1450
1451 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1452 <dd>Floating point extend a constant to another type. The size of CST must be
1453 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1454
1455 <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt>
1456 <dd>Convert a floating point constant to the corresponding unsigned integer
1457 constant. TYPE must be an integer type. CST must be floating point. If the
1458 value won't fit in the integer type, the results are undefined.</dd>
1459
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1460 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1461 <dd>Convert a floating point constant to the corresponding signed integer
1462 constant. TYPE must be an integer type. CST must be floating point. If the
1463 value won't fit in the integer type, the results are undefined.</dd>
1464
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1465 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1466 <dd>Convert an unsigned integer constant to the corresponding floating point
1467 constant. TYPE must be floating point. CST must be of integer type. If the
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]1468 value won't fit in the floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1469
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1470 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1471 <dd>Convert a signed integer constant to the corresponding floating point
1472 constant. TYPE must be floating point. CST must be of integer type. If the
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]1473 value won't fit in the floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1474
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1475 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1476 <dd>Convert a pointer typed constant to the corresponding integer constant
1477 TYPE must be an integer type. CST must be of pointer type. The CST value is
1478 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1479
1480 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1481 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1482 pointer type. CST must be of integer type. The CST value is zero extended,
1483 truncated, or unchanged to make it fit in a pointer size. This one is
1484 <i>really</i> dangerous!</dd>
1485
1486 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1487 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1488 identical (same number of bits). The conversion is done as if the CST value
1489 was stored to memory and read back as TYPE. In other words, no bits change
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1490 with this operator, just the type. This can be used for conversion of
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1491 vector types to any other type, as long as they have the same bit width. For
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1492 pointers it is only valid to cast to another pointer type.
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1493 </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1494
1495 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1496
1497 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1498 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1499 instruction, the index list may have zero or more indexes, which are required
1500 to make sense for the type of "CSTPTR".</dd>
1501
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1502 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1503
1504 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1505 constants.</dd>
1506
1507 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1508 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1509
1510 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1511 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1512
1513 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1514
1515 <dd>Perform the <a href="#i_extractelement">extractelement
1516 operation</a> on constants.
1517
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1518 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1519
1520 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1521 operation</a> on constants.</dd>
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1522
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1523
1524 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1525
1526 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1527 operation</a> on constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1528
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1529 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1530
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1531 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1532 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1533 binary</a> operations. The constraints on operands are the same as those for
1534 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1535 values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1536</dl>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1537</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]1538
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1539<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1540<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1541<!-- *********************************************************************** -->
1542
1543<!-- ======================================================================= -->
1544<div class="doc_subsection">
1545<a name="inlineasm">Inline Assembler Expressions</a>
1546</div>
1547
1548<div class="doc_text">
1549
1550<p>
1551LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1552Module-Level Inline Assembly</a>) through the use of a special value. This
1553value represents the inline assembler as a string (containing the instructions
1554to emit), a list of operand constraints (stored as a string), and a flag that
1555indicates whether or not the inline asm expression has side effects. An example
1556inline assembler expression is:
1557</p>
1558
1559<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1560 i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1561</pre>
1562
1563<p>
1564Inline assembler expressions may <b>only</b> be used as the callee operand of
1565a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1566</p>
1567
1568<pre>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]1569 %X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1570</pre>
1571
1572<p>
1573Inline asms with side effects not visible in the constraint list must be marked
1574as having side effects. This is done through the use of the
1575'<tt>sideeffect</tt>' keyword, like so:
1576</p>
1577
1578<pre>
1579 call void asm sideeffect "eieio", ""()
1580</pre>
1581
1582<p>TODO: The format of the asm and constraints string still need to be
1583documented here. Constraints on what can be done (e.g. duplication, moving, etc
1584need to be documented).
1585</p>
1586
1587</div>
1588
1589<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1590<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1591<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1592
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1593<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1594
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1595<p>The LLVM instruction set consists of several different
1596classifications of instructions: <a href="#terminators">terminator
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1597instructions</a>, <a href="#binaryops">binary instructions</a>,
1598<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1599 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1600instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1601
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1602</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1603
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1604<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1605<div class="doc_subsection"> <a name="terminators">Terminator
1606Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1607
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1608<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1609
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1610<p>As mentioned <a href="#functionstructure">previously</a>, every
1611basic block in a program ends with a "Terminator" instruction, which
1612indicates which block should be executed after the current block is
1613finished. These terminator instructions typically yield a '<tt>void</tt>'
1614value: they produce control flow, not values (the one exception being
1615the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1616<p>There are six different terminator instructions: the '<a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1617 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1618instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1619the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1620 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1621 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1622
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1623</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1624
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1625<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1626<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1627Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1628<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1629<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1630<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]1631 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1632</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1633<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1634<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1635value) from a function back to the caller.</p>
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]1636<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1637returns a value and then causes control flow, and one that just causes
1638control flow to occur.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1639<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1640<p>The '<tt>ret</tt>' instruction may return any '<a
1641 href="#t_firstclass">first class</a>' type. Notice that a function is
1642not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1643instruction inside of the function that returns a value that does not
1644match the return type of the function.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1645<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1646<p>When the '<tt>ret</tt>' instruction is executed, control flow
1647returns back to the calling function's context. If the caller is a "<a
John Criswell40db33f2004-06-25 15:16:57 +0000[diff] [blame]1648 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1649the instruction after the call. If the caller was an "<a
1650 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1651at the beginning of the "normal" destination block. If the instruction
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1652returns a value, that value shall set the call or invoke instruction's
1653return value.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1654<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1655<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1656 ret void <i>; Return from a void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1657</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1658</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1659<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1660<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1661<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1662<h5>Syntax:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1663<pre> br i1 &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]1664</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1665<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1666<p>The '<tt>br</tt>' instruction is used to cause control flow to
1667transfer to a different basic block in the current function. There are
1668two forms of this instruction, corresponding to a conditional branch
1669and an unconditional branch.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1670<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1671<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1672single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1673unconditional form of the '<tt>br</tt>' instruction takes a single
1674'<tt>label</tt>' value as a target.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1675<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1676<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1677argument is evaluated. If the value is <tt>true</tt>, control flows
1678to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1679control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1680<h5>Example:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1681<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq, i32 %a, %b<br> br i1 %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1682 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1683</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1684<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1685<div class="doc_subsubsection">
1686 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1687</div>
1688
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1689<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1690<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1691
1692<pre>
1693 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1694</pre>
1695
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1696<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1697
1698<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1699several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1700instruction, allowing a branch to occur to one of many possible
1701destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1702
1703
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1704<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1705
1706<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1707comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1708an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1709table is not allowed to contain duplicate constant entries.</p>
1710
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1711<h5>Semantics:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1712
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1713<p>The <tt>switch</tt> instruction specifies a table of values and
1714destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1715table is searched for the given value. If the value is found, control flow is
1716transfered to the corresponding destination; otherwise, control flow is
1717transfered to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1718
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1719<h5>Implementation:</h5>
1720
1721<p>Depending on properties of the target machine and the particular
1722<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1723ways. For example, it could be generated as a series of chained conditional
1724branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1725
1726<h5>Example:</h5>
1727
1728<pre>
1729 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1730 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1731 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1732
1733 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1734 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1735
1736 <i>; Implement a jump table:</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1737 switch i32 %val, label %otherwise [ i32 0, label %onzero
1738 i32 1, label %onone
1739 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1740</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1741</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1742
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1743<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1744<div class="doc_subsubsection">
1745 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1746</div>
1747
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1748<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1749
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1750<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1751
1752<pre>
1753 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] &lt;ptr to function ty&gt; %&lt;function ptr val&gt;(&lt;function args&gt;)
Chris Lattner6b7a0082006-05-14 18:23:06 +0000[diff] [blame]1754 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1755</pre>
1756
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]1757<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1758
1759<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1760function, with the possibility of control flow transfer to either the
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1761'<tt>normal</tt>' label or the
1762'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1763"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1764"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1765href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1766continued at the dynamically nearest "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1767
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1768<h5>Arguments:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1769
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1770<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1771
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1772<ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1773 <li>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]1774 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1775 convention</a> the call should use. If none is specified, the call defaults
1776 to using C calling conventions.
1777 </li>
1778 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1779 function value being invoked. In most cases, this is a direct function
1780 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1781 an arbitrary pointer to function value.
1782 </li>
1783
1784 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1785 function to be invoked. </li>
1786
1787 <li>'<tt>function args</tt>': argument list whose types match the function
1788 signature argument types. If the function signature indicates the function
1789 accepts a variable number of arguments, the extra arguments can be
1790 specified. </li>
1791
1792 <li>'<tt>normal label</tt>': the label reached when the called function
1793 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1794
1795 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1796 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1797
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1798</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1799
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1800<h5>Semantics:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1801
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1802<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1803href="#i_call">call</a></tt>' instruction in most regards. The primary
1804difference is that it establishes an association with a label, which is used by
1805the runtime library to unwind the stack.</p>
1806
1807<p>This instruction is used in languages with destructors to ensure that proper
1808cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1809exception. Additionally, this is important for implementation of
1810'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1811
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1812<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1813<pre>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1814 %retval = invoke i32 %Test(i32 15) to label %Continue
1815 unwind label %TestCleanup <i>; {i32}:retval set</i>
1816 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1817 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1818</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1819</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1820
1821
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1822<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1823
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1824<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1825Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1826
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1827<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1828
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1829<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1830<pre>
1831 unwind
1832</pre>
1833
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1834<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1835
1836<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1837at the first callee in the dynamic call stack which used an <a
1838href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1839primarily used to implement exception handling.</p>
1840
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1841<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1842
1843<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1844immediately halt. The dynamic call stack is then searched for the first <a
1845href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1846execution continues at the "exceptional" destination block specified by the
1847<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1848dynamic call chain, undefined behavior results.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1849</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1850
1851<!-- _______________________________________________________________________ -->
1852
1853<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1854Instruction</a> </div>
1855
1856<div class="doc_text">
1857
1858<h5>Syntax:</h5>
1859<pre>
1860 unreachable
1861</pre>
1862
1863<h5>Overview:</h5>
1864
1865<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1866instruction is used to inform the optimizer that a particular portion of the
1867code is not reachable. This can be used to indicate that the code after a
1868no-return function cannot be reached, and other facts.</p>
1869
1870<h5>Semantics:</h5>
1871
1872<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1873</div>
1874
1875
1876
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1877<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1878<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1879<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1880<p>Binary operators are used to do most of the computation in a
1881program. They require two operands, execute an operation on them, and
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1882produce a single value. The operands might represent
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1883multiple data, as is the case with the <a href="#t_vector">vector</a> data type.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1884The result value of a binary operator is not
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1885necessarily the same type as its operands.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1886<p>There are several different binary operators:</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1887</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1888<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1889<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1890Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1891<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1892<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1893<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]1894</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1895<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1896<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1897<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1898<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1899 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1900 This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1901Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1902<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1903<p>The value produced is the integer or floating point sum of the two
1904operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1905<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1906<pre> &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1907</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1908</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1909<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1910<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1911Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1912<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1913<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1914<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]1915</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1916<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1917<p>The '<tt>sub</tt>' instruction returns the difference of its two
1918operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1919<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1920instruction present in most other intermediate representations.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1921<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1922<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1923 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1924values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1925This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1926Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1927<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1928<p>The value produced is the integer or floating point difference of
1929the two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1930<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1931<pre> &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
1932 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1933</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1934</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1935<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1936<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1937Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1938<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1939<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1940<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]1941</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1942<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1943<p>The '<tt>mul</tt>' instruction returns the product of its two
1944operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1945<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1946<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1947 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1948values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1949This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1950Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1951<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1952<p>The value produced is the integer or floating point product of the
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1953two operands.</p>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1954<p>Because the operands are the same width, the result of an integer
1955multiplication is the same whether the operands should be deemed unsigned or
1956signed.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1957<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1958<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1959</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1960</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1961<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1962<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
1963</a></div>
1964<div class="doc_text">
1965<h5>Syntax:</h5>
1966<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1967</pre>
1968<h5>Overview:</h5>
1969<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
1970operands.</p>
1971<h5>Arguments:</h5>
1972<p>The two arguments to the '<tt>udiv</tt>' instruction must be
1973<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1974types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1975of the values in which case the elements must be integers.</p>
1976<h5>Semantics:</h5>
1977<p>The value produced is the unsigned integer quotient of the two operands. This
1978instruction always performs an unsigned division operation, regardless of
1979whether the arguments are unsigned or not.</p>
1980<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1981<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1982</pre>
1983</div>
1984<!-- _______________________________________________________________________ -->
1985<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
1986</a> </div>
1987<div class="doc_text">
1988<h5>Syntax:</h5>
1989<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1990</pre>
1991<h5>Overview:</h5>
1992<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
1993operands.</p>
1994<h5>Arguments:</h5>
1995<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
1996<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1997types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1998of the values in which case the elements must be integers.</p>
1999<h5>Semantics:</h5>
2000<p>The value produced is the signed integer quotient of the two operands. This
2001instruction always performs a signed division operation, regardless of whether
2002the arguments are signed or not.</p>
2003<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2004<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2005</pre>
2006</div>
2007<!-- _______________________________________________________________________ -->
2008<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2009Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2010<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2011<h5>Syntax:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2012<pre> &lt;result&gt; = fdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2013</pre>
2014<h5>Overview:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2015<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2016operands.</p>
2017<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2018<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2019<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2020identical types. This instruction can also take <a href="#t_vector">vector</a>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2021versions of floating point values.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2022<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2023<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2024<h5>Example:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2025<pre> &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2026</pre>
2027</div>
2028<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2029<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2030</div>
2031<div class="doc_text">
2032<h5>Syntax:</h5>
2033<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2034</pre>
2035<h5>Overview:</h5>
2036<p>The '<tt>urem</tt>' instruction returns the remainder from the
2037unsigned division of its two arguments.</p>
2038<h5>Arguments:</h5>
2039<p>The two arguments to the '<tt>urem</tt>' instruction must be
2040<a href="#t_integer">integer</a> values. Both arguments must have identical
2041types.</p>
2042<h5>Semantics:</h5>
2043<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
2044This instruction always performs an unsigned division to get the remainder,
2045regardless of whether the arguments are unsigned or not.</p>
2046<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2047<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2048</pre>
2049
2050</div>
2051<!-- _______________________________________________________________________ -->
2052<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2053Instruction</a> </div>
2054<div class="doc_text">
2055<h5>Syntax:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2056<pre> &lt;result&gt; = srem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2057</pre>
2058<h5>Overview:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2059<p>The '<tt>srem</tt>' instruction returns the remainder from the
2060signed division of its two operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2061<h5>Arguments:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2062<p>The two arguments to the '<tt>srem</tt>' instruction must be
2063<a href="#t_integer">integer</a> values. Both arguments must have identical
2064types.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2065<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2066<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2067has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2068operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2069a value. For more information about the difference, see <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2070 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2071Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencerdb3b93b2007-03-24 22:40:44 +0000[diff] [blame]2072please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2073Wikipedia: modulo operation</a>.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2074<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2075<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2076</pre>
2077
2078</div>
2079<!-- _______________________________________________________________________ -->
2080<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2081Instruction</a> </div>
2082<div class="doc_text">
2083<h5>Syntax:</h5>
2084<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2085</pre>
2086<h5>Overview:</h5>
2087<p>The '<tt>frem</tt>' instruction returns the remainder from the
2088division of its two operands.</p>
2089<h5>Arguments:</h5>
2090<p>The two arguments to the '<tt>frem</tt>' instruction must be
2091<a href="#t_floating">floating point</a> values. Both arguments must have
2092identical types.</p>
2093<h5>Semantics:</h5>
2094<p>This instruction returns the <i>remainder</i> of a division.</p>
2095<h5>Example:</h5>
2096<pre> &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2097</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2098</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]2099
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2100<!-- ======================================================================= -->
2101<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2102Operations</a> </div>
2103<div class="doc_text">
2104<p>Bitwise binary operators are used to do various forms of
2105bit-twiddling in a program. They are generally very efficient
2106instructions and can commonly be strength reduced from other
2107instructions. They require two operands, execute an operation on them,
2108and produce a single value. The resulting value of the bitwise binary
2109operators is always the same type as its first operand.</p>
2110</div>
2111
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2112<!-- _______________________________________________________________________ -->
2113<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2114Instruction</a> </div>
2115<div class="doc_text">
2116<h5>Syntax:</h5>
2117<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2118</pre>
2119<h5>Overview:</h5>
2120<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2121the left a specified number of bits.</p>
2122<h5>Arguments:</h5>
2123<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2124 href="#t_integer">integer</a> type.</p>
2125<h5>Semantics:</h5>
2126<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
2127<h5>Example:</h5><pre>
2128 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2129 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2130 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
2131</pre>
2132</div>
2133<!-- _______________________________________________________________________ -->
2134<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2135Instruction</a> </div>
2136<div class="doc_text">
2137<h5>Syntax:</h5>
2138<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2139</pre>
2140
2141<h5>Overview:</h5>
2142<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2143operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2144
2145<h5>Arguments:</h5>
2146<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2147<a href="#t_integer">integer</a> type.</p>
2148
2149<h5>Semantics:</h5>
2150<p>This instruction always performs a logical shift right operation. The most
2151significant bits of the result will be filled with zero bits after the
2152shift.</p>
2153
2154<h5>Example:</h5>
2155<pre>
2156 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2157 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2158 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2159 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
2160</pre>
2161</div>
2162
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2163<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2164<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2165Instruction</a> </div>
2166<div class="doc_text">
2167
2168<h5>Syntax:</h5>
2169<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2170</pre>
2171
2172<h5>Overview:</h5>
2173<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2174operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2175
2176<h5>Arguments:</h5>
2177<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2178<a href="#t_integer">integer</a> type.</p>
2179
2180<h5>Semantics:</h5>
2181<p>This instruction always performs an arithmetic shift right operation,
2182The most significant bits of the result will be filled with the sign bit
2183of <tt>var1</tt>.</p>
2184
2185<h5>Example:</h5>
2186<pre>
2187 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2188 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2189 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2190 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
2191</pre>
2192</div>
2193
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2194<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2195<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2196Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2197<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2198<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2199<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]2200</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2201<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2202<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2203its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2204<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2205<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2206 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2207identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2208<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2209<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2210<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2211<div style="align: center">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2212<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2213 <tbody>
2214 <tr>
2215 <td>In0</td>
2216 <td>In1</td>
2217 <td>Out</td>
2218 </tr>
2219 <tr>
2220 <td>0</td>
2221 <td>0</td>
2222 <td>0</td>
2223 </tr>
2224 <tr>
2225 <td>0</td>
2226 <td>1</td>
2227 <td>0</td>
2228 </tr>
2229 <tr>
2230 <td>1</td>
2231 <td>0</td>
2232 <td>0</td>
2233 </tr>
2234 <tr>
2235 <td>1</td>
2236 <td>1</td>
2237 <td>1</td>
2238 </tr>
2239 </tbody>
2240</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2241</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2242<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2243<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2244 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2245 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2246</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2247</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2248<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2249<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2250<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2251<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2252<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]2253</pre>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2254<h5>Overview:</h5>
2255<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2256or of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2257<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2258<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2259 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2260identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2261<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2262<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2263<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2264<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2265<table border="1" cellspacing="0" cellpadding="4">
2266 <tbody>
2267 <tr>
2268 <td>In0</td>
2269 <td>In1</td>
2270 <td>Out</td>
2271 </tr>
2272 <tr>
2273 <td>0</td>
2274 <td>0</td>
2275 <td>0</td>
2276 </tr>
2277 <tr>
2278 <td>0</td>
2279 <td>1</td>
2280 <td>1</td>
2281 </tr>
2282 <tr>
2283 <td>1</td>
2284 <td>0</td>
2285 <td>1</td>
2286 </tr>
2287 <tr>
2288 <td>1</td>
2289 <td>1</td>
2290 <td>1</td>
2291 </tr>
2292 </tbody>
2293</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2294</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2295<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2296<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2297 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2298 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2299</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2300</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2301<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2302<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2303Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2304<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2305<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2306<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]2307</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2308<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2309<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2310or of its two operands. The <tt>xor</tt> is used to implement the
2311"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2312<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2313<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2314 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2315identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2316<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2317<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2318<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2319<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2320<table border="1" cellspacing="0" cellpadding="4">
2321 <tbody>
2322 <tr>
2323 <td>In0</td>
2324 <td>In1</td>
2325 <td>Out</td>
2326 </tr>
2327 <tr>
2328 <td>0</td>
2329 <td>0</td>
2330 <td>0</td>
2331 </tr>
2332 <tr>
2333 <td>0</td>
2334 <td>1</td>
2335 <td>1</td>
2336 </tr>
2337 <tr>
2338 <td>1</td>
2339 <td>0</td>
2340 <td>1</td>
2341 </tr>
2342 <tr>
2343 <td>1</td>
2344 <td>1</td>
2345 <td>0</td>
2346 </tr>
2347 </tbody>
2348</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2349</div>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2350<p> </p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2351<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2352<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2353 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2354 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2355 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2356</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2357</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2358
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2359<!-- ======================================================================= -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2360<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2361 <a name="vectorops">Vector Operations</a>
2362</div>
2363
2364<div class="doc_text">
2365
2366<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2367target-independent manner. These instructions cover the element-access and
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2368vector-specific operations needed to process vectors effectively. While LLVM
2369does directly support these vector operations, many sophisticated algorithms
2370will want to use target-specific intrinsics to take full advantage of a specific
2371target.</p>
2372
2373</div>
2374
2375<!-- _______________________________________________________________________ -->
2376<div class="doc_subsubsection">
2377 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2378</div>
2379
2380<div class="doc_text">
2381
2382<h5>Syntax:</h5>
2383
2384<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2385 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2386</pre>
2387
2388<h5>Overview:</h5>
2389
2390<p>
2391The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2392element from a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2393</p>
2394
2395
2396<h5>Arguments:</h5>
2397
2398<p>
2399The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2400value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2401an index indicating the position from which to extract the element.
2402The index may be a variable.</p>
2403
2404<h5>Semantics:</h5>
2405
2406<p>
2407The result is a scalar of the same type as the element type of
2408<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2409<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2410results are undefined.
2411</p>
2412
2413<h5>Example:</h5>
2414
2415<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2416 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2417</pre>
2418</div>
2419
2420
2421<!-- _______________________________________________________________________ -->
2422<div class="doc_subsubsection">
2423 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2424</div>
2425
2426<div class="doc_text">
2427
2428<h5>Syntax:</h5>
2429
2430<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2431 &lt;result&gt; = insertelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt, i32 &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2432</pre>
2433
2434<h5>Overview:</h5>
2435
2436<p>
2437The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2438element into a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2439</p>
2440
2441
2442<h5>Arguments:</h5>
2443
2444<p>
2445The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2446value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2447scalar value whose type must equal the element type of the first
2448operand. The third operand is an index indicating the position at
2449which to insert the value. The index may be a variable.</p>
2450
2451<h5>Semantics:</h5>
2452
2453<p>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2454The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2455element values are those of <tt>val</tt> except at position
2456<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2457exceeds the length of <tt>val</tt>, the results are undefined.
2458</p>
2459
2460<h5>Example:</h5>
2461
2462<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2463 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2464</pre>
2465</div>
2466
2467<!-- _______________________________________________________________________ -->
2468<div class="doc_subsubsection">
2469 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2470</div>
2471
2472<div class="doc_text">
2473
2474<h5>Syntax:</h5>
2475
2476<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2477 &lt;result&gt; = shufflevector &lt;n x &lt;ty&gt;&gt; &lt;v1&gt;, &lt;n x &lt;ty&gt;&gt; &lt;v2&gt;, &lt;n x i32&gt; &lt;mask&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2478</pre>
2479
2480<h5>Overview:</h5>
2481
2482<p>
2483The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2484from two input vectors, returning a vector of the same type.
2485</p>
2486
2487<h5>Arguments:</h5>
2488
2489<p>
2490The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2491with types that match each other and types that match the result of the
2492instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2493of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2494</p>
2495
2496<p>
2497The shuffle mask operand is required to be a constant vector with either
2498constant integer or undef values.
2499</p>
2500
2501<h5>Semantics:</h5>
2502
2503<p>
2504The elements of the two input vectors are numbered from left to right across
2505both of the vectors. The shuffle mask operand specifies, for each element of
2506the result vector, which element of the two input registers the result element
2507gets. The element selector may be undef (meaning "don't care") and the second
2508operand may be undef if performing a shuffle from only one vector.
2509</p>
2510
2511<h5>Example:</h5>
2512
2513<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2514 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2515 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2516 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2517 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i> - Identity shuffle.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2518</pre>
2519</div>
2520
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]2521
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2522<!-- ======================================================================= -->
2523<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]2524 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2525</div>
2526
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2527<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2528
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2529<p>A key design point of an SSA-based representation is how it
2530represents memory. In LLVM, no memory locations are in SSA form, which
2531makes things very simple. This section describes how to read, write,
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2532allocate, and free memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2533
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2534</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2535
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2536<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2537<div class="doc_subsubsection">
2538 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2539</div>
2540
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2541<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2542
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2543<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2544
2545<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2546 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2547</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2548
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2549<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2550
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2551<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2552heap and returns a pointer to it.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2553
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2554<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2555
2556<p>The '<tt>malloc</tt>' instruction allocates
2557<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswella92e5862004-02-24 16:13:56 +0000[diff] [blame]2558bytes of memory from the operating system and returns a pointer of the
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2559appropriate type to the program. If "NumElements" is specified, it is the
2560number of elements allocated. If an alignment is specified, the value result
2561of the allocation is guaranteed to be aligned to at least that boundary. If
2562not specified, or if zero, the target can choose to align the allocation on any
2563convenient boundary.</p>
2564
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2565<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2566
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2567<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2568
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2569<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2570a pointer is returned.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2571
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2572<h5>Example:</h5>
2573
2574<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2575 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2576
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2577 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2578 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2579 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2580 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2581 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2582</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2583</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2584
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2585<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2586<div class="doc_subsubsection">
2587 <a name="i_free">'<tt>free</tt>' Instruction</a>
2588</div>
2589
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2590<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2591
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2592<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2593
2594<pre>
2595 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2596</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2597
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2598<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2599
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2600<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2601memory heap to be reallocated in the future.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2602
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2603<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2604
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2605<p>'<tt>value</tt>' shall be a pointer value that points to a value
2606that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2607instruction.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2608
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2609<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2610
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2611<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2612after this instruction executes.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2613
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2614<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2615
2616<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2617 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2618 free [4 x i8]* %array
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2619</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2620</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2621
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2622<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2623<div class="doc_subsubsection">
2624 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2625</div>
2626
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2627<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2628
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2629<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2630
2631<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2632 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2633</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2634
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2635<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2636
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2637<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
2638currently executing function, to be automatically released when this function
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2639returns to its caller.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2640
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2641<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2642
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2643<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2644bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2645appropriate type to the program. If "NumElements" is specified, it is the
2646number of elements allocated. If an alignment is specified, the value result
2647of the allocation is guaranteed to be aligned to at least that boundary. If
2648not specified, or if zero, the target can choose to align the allocation on any
2649convenient boundary.</p>
2650
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2651<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2652
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2653<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2654
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2655<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2656memory is automatically released when the function returns. The '<tt>alloca</tt>'
2657instruction is commonly used to represent automatic variables that must
2658have an address available. When the function returns (either with the <tt><a
John Criswellc932bef2005-05-12 16:55:34 +0000[diff] [blame]2659 href="#i_ret">ret</a></tt> or <tt><a href="#i_unwind">unwind</a></tt>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2660instructions), the memory is reclaimed.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2661
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2662<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2663
2664<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2665 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
2666 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2667 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
2668 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2669</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2670</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2671
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2672<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2673<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2674Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2675<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2676<h5>Syntax:</h5>
Christopher Lambbff50202007-04-21 08:16:25 +0000[diff] [blame]2677<pre> &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br> &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br></pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2678<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2679<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2680<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2681<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2682address from which to load. The pointer must point to a <a
Chris Lattner10ee9652004-06-03 22:57:15 +0000[diff] [blame]2683 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2684marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2685the number or order of execution of this <tt>load</tt> with other
2686volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2687instructions. </p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2688<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2689<p>The location of memory pointed to is loaded.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2690<h5>Examples:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2691<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2692 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2693 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2694 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2695</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2696</div>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2697<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2698<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2699Instruction</a> </div>
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]2700<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2701<h5>Syntax:</h5>
Christopher Lambbff50202007-04-21 08:16:25 +0000[diff] [blame]2702<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
2703 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2704</pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2705<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2706<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2707<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2708<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2709to store and an address at which to store it. The type of the '<tt>&lt;pointer&gt;</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2710operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2711operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2712optimizer is not allowed to modify the number or order of execution of
2713this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2714 href="#i_store">store</a></tt> instructions.</p>
2715<h5>Semantics:</h5>
2716<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2717at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2718<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2719<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2720 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2721 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2722 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2723</pre>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]2724</div>
2725
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2726<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2727<div class="doc_subsubsection">
2728 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2729</div>
2730
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2731<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2732<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2733<pre>
2734 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2735</pre>
2736
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2737<h5>Overview:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2738
2739<p>
2740The '<tt>getelementptr</tt>' instruction is used to get the address of a
2741subelement of an aggregate data structure.</p>
2742
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2743<h5>Arguments:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2744
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2745<p>This instruction takes a list of integer operands that indicate what
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2746elements of the aggregate object to index to. The actual types of the arguments
2747provided depend on the type of the first pointer argument. The
2748'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]2749levels of a structure or to a specific index in an array. When indexing into a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2750structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2751into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2752be sign extended to 64-bit values.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2753
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2754<p>For example, let's consider a C code fragment and how it gets
2755compiled to LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2756
2757<pre>
2758 struct RT {
2759 char A;
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2760 i32 B[10][20];
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2761 char C;
2762 };
2763 struct ST {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2764 i32 X;
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2765 double Y;
2766 struct RT Z;
2767 };
2768
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2769 define i32 *foo(struct ST *s) {
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2770 return &amp;s[1].Z.B[5][13];
2771 }
2772</pre>
2773
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2774<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2775
2776<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2777 %RT = type { i8 , [10 x [20 x i32]], i8 }
2778 %ST = type { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2779
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2780 define i32* %foo(%ST* %s) {
Brian Gaeke317ef962004-07-02 21:08:14 +0000[diff] [blame]2781 entry:
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2782 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2783 ret i32* %reg
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2784 }
2785</pre>
2786
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2787<h5>Semantics:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2788
2789<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2790on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2791and <a href="#t_array">array</a> types can use a 32-bit or 64-bit
Reid Spencerc0312692006-12-03 16:53:48 +0000[diff] [blame]2792<a href="#t_integer">integer</a> type but the value will always be sign extended
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2793to 64-bits. <a href="#t_struct">Structure</a> types require <tt>i32</tt>
Reid Spencerc0312692006-12-03 16:53:48 +0000[diff] [blame]2794<b>constants</b>.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2795
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2796<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2797type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2798}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2799the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2800i8 }</tt>' type, another structure. The third index indexes into the second
2801element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2802array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2803'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2804to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2805
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2806<p>Note that it is perfectly legal to index partially through a
2807structure, returning a pointer to an inner element. Because of this,
2808the LLVM code for the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2809
2810<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2811 define i32* %foo(%ST* %s) {
2812 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2813 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2814 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2815 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2816 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2817 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2818 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2819</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]2820
2821<p>Note that it is undefined to access an array out of bounds: array and
2822pointer indexes must always be within the defined bounds of the array type.
2823The one exception for this rules is zero length arrays. These arrays are
2824defined to be accessible as variable length arrays, which requires access
2825beyond the zero'th element.</p>
2826
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]2827<p>The getelementptr instruction is often confusing. For some more insight
2828into how it works, see <a href="GetElementPtr.html">the getelementptr
2829FAQ</a>.</p>
2830
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2831<h5>Example:</h5>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]2832
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2833<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2834 <i>; yields [12 x i8]*:aptr</i>
2835 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2836</pre>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2837</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]2838
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2839<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]2840<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2841</div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2842<div class="doc_text">
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]2843<p>The instructions in this category are the conversion instructions (casting)
2844which all take a single operand and a type. They perform various bit conversions
2845on the operand.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2846</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2847
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2848<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2849<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2850 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2851</div>
2852<div class="doc_text">
2853
2854<h5>Syntax:</h5>
2855<pre>
2856 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2857</pre>
2858
2859<h5>Overview:</h5>
2860<p>
2861The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2862</p>
2863
2864<h5>Arguments:</h5>
2865<p>
2866The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2867be an <a href="#t_integer">integer</a> type, and a type that specifies the size
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2868and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2869type. The bit size of <tt>value</tt> must be larger than the bit size of
2870<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2871
2872<h5>Semantics:</h5>
2873<p>
2874The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2875and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2876larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2877It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2878
2879<h5>Example:</h5>
2880<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2881 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2882 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
2883 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2884</pre>
2885</div>
2886
2887<!-- _______________________________________________________________________ -->
2888<div class="doc_subsubsection">
2889 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2890</div>
2891<div class="doc_text">
2892
2893<h5>Syntax:</h5>
2894<pre>
2895 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2896</pre>
2897
2898<h5>Overview:</h5>
2899<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2900<tt>ty2</tt>.</p>
2901
2902
2903<h5>Arguments:</h5>
2904<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2905<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2906also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2907<tt>value</tt> must be smaller than the bit size of the destination type,
2908<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2909
2910<h5>Semantics:</h5>
2911<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Chris Lattnerc87f3df2007-05-24 19:13:27 +0000[diff] [blame^]2912bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2913
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]2914<p>When zero extending from i1, the result will always be either 0 or 1.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2915
2916<h5>Example:</h5>
2917<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2918 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2919 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2920</pre>
2921</div>
2922
2923<!-- _______________________________________________________________________ -->
2924<div class="doc_subsubsection">
2925 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
2926</div>
2927<div class="doc_text">
2928
2929<h5>Syntax:</h5>
2930<pre>
2931 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2932</pre>
2933
2934<h5>Overview:</h5>
2935<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
2936
2937<h5>Arguments:</h5>
2938<p>
2939The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2940<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2941also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2942<tt>value</tt> must be smaller than the bit size of the destination type,
2943<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2944
2945<h5>Semantics:</h5>
2946<p>
2947The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
2948bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
Chris Lattnerc87f3df2007-05-24 19:13:27 +0000[diff] [blame^]2949the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2950
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2951<p>When sign extending from i1, the extension always results in -1 or 0.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2952
2953<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2954<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2955 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2956 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2957</pre>
2958</div>
2959
2960<!-- _______________________________________________________________________ -->
2961<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]2962 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
2963</div>
2964
2965<div class="doc_text">
2966
2967<h5>Syntax:</h5>
2968
2969<pre>
2970 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2971</pre>
2972
2973<h5>Overview:</h5>
2974<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
2975<tt>ty2</tt>.</p>
2976
2977
2978<h5>Arguments:</h5>
2979<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
2980 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
2981cast it to. The size of <tt>value</tt> must be larger than the size of
2982<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
2983<i>no-op cast</i>.</p>
2984
2985<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2986<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
2987<a href="#t_floating">floating point</a> type to a smaller
2988<a href="#t_floating">floating point</a> type. If the value cannot fit within
2989the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]2990
2991<h5>Example:</h5>
2992<pre>
2993 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
2994 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
2995</pre>
2996</div>
2997
2998<!-- _______________________________________________________________________ -->
2999<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3000 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3001</div>
3002<div class="doc_text">
3003
3004<h5>Syntax:</h5>
3005<pre>
3006 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3007</pre>
3008
3009<h5>Overview:</h5>
3010<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3011floating point value.</p>
3012
3013<h5>Arguments:</h5>
3014<p>The '<tt>fpext</tt>' instruction takes a
3015<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3016and a <a href="#t_floating">floating point</a> type to cast it to. The source
3017type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3018
3019<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3020<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3021<a href="#t_floating">floating point</a> type to a larger
3022<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3023used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3024<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3025
3026<h5>Example:</h5>
3027<pre>
3028 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3029 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3030</pre>
3031</div>
3032
3033<!-- _______________________________________________________________________ -->
3034<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]3035 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3036</div>
3037<div class="doc_text">
3038
3039<h5>Syntax:</h5>
3040<pre>
3041 &lt;result&gt; = fp2uint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3042</pre>
3043
3044<h5>Overview:</h5>
3045<p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its
3046unsigned integer equivalent of type <tt>ty2</tt>.
3047</p>
3048
3049<h5>Arguments:</h5>
3050<p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a
3051<a href="#t_floating">floating point</a> value, and a type to cast it to, which
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3052must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3053
3054<h5>Semantics:</h5>
3055<p> The '<tt>fp2uint</tt>' instruction converts its
3056<a href="#t_floating">floating point</a> operand into the nearest (rounding
3057towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3058the results are undefined.</p>
3059
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3060<p>When converting to i1, the conversion is done as a comparison against
3061zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3062If the <tt>value</tt> was non-zero, the i1 result will be <tt>true</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3063
3064<h5>Example:</h5>
3065<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3066 %X = fp2uint double 123.0 to i32 <i>; yields i32:123</i>
3067 %Y = fp2uint float 1.0E+300 to i1 <i>; yields i1:true</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3068 %X = fp2uint float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3069</pre>
3070</div>
3071
3072<!-- _______________________________________________________________________ -->
3073<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3074 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3075</div>
3076<div class="doc_text">
3077
3078<h5>Syntax:</h5>
3079<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3080 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3081</pre>
3082
3083<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3084<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3085<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3086</p>
3087
3088
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3089<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3090<p> The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3091<a href="#t_floating">floating point</a> value, and a type to cast it to, which
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3092must also be an <a href="#t_integer">integer</a> type.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3093
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3094<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3095<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3096<a href="#t_floating">floating point</a> operand into the nearest (rounding
3097towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3098the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3099
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3100<p>When converting to i1, the conversion is done as a comparison against
3101zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3102If the <tt>value</tt> was non-zero, the i1 result will be <tt>true</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3103
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3104<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3105<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3106 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
3107 %Y = fptosi float 1.0E-247 to i1 <i>; yields i1:true</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3108 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3109</pre>
3110</div>
3111
3112<!-- _______________________________________________________________________ -->
3113<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3114 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3115</div>
3116<div class="doc_text">
3117
3118<h5>Syntax:</h5>
3119<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3120 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3121</pre>
3122
3123<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3124<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3125integer and converts that value to the <tt>ty2</tt> type.</p>
3126
3127
3128<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3129<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be an
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3130<a href="#t_integer">integer</a> value, and a type to cast it to, which must
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3131be a <a href="#t_floating">floating point</a> type.</p>
3132
3133<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3134<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3135integer quantity and converts it to the corresponding floating point value. If
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]3136the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3137
3138
3139<h5>Example:</h5>
3140<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3141 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3142 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3143</pre>
3144</div>
3145
3146<!-- _______________________________________________________________________ -->
3147<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3148 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3149</div>
3150<div class="doc_text">
3151
3152<h5>Syntax:</h5>
3153<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3154 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3155</pre>
3156
3157<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3158<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3159integer and converts that value to the <tt>ty2</tt> type.</p>
3160
3161<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3162<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be an
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3163<a href="#t_integer">integer</a> value, and a type to cast it to, which must be
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3164a <a href="#t_floating">floating point</a> type.</p>
3165
3166<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3167<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3168integer quantity and converts it to the corresponding floating point value. If
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]3169the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3170
3171<h5>Example:</h5>
3172<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3173 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3174 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3175</pre>
3176</div>
3177
3178<!-- _______________________________________________________________________ -->
3179<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3180 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3181</div>
3182<div class="doc_text">
3183
3184<h5>Syntax:</h5>
3185<pre>
3186 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3187</pre>
3188
3189<h5>Overview:</h5>
3190<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3191the integer type <tt>ty2</tt>.</p>
3192
3193<h5>Arguments:</h5>
3194<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3195must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3196<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3197
3198<h5>Semantics:</h5>
3199<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3200<tt>ty2</tt> by interpreting the pointer value as an integer and either
3201truncating or zero extending that value to the size of the integer type. If
3202<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3203<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3204are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3205change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3206
3207<h5>Example:</h5>
3208<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3209 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3210 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3211</pre>
3212</div>
3213
3214<!-- _______________________________________________________________________ -->
3215<div class="doc_subsubsection">
3216 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3217</div>
3218<div class="doc_text">
3219
3220<h5>Syntax:</h5>
3221<pre>
3222 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3223</pre>
3224
3225<h5>Overview:</h5>
3226<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3227a pointer type, <tt>ty2</tt>.</p>
3228
3229<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3230<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3231value to cast, and a type to cast it to, which must be a
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]3232<a href="#t_pointer">pointer</a> type.
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3233
3234<h5>Semantics:</h5>
3235<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3236<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3237the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3238size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3239the size of a pointer then a zero extension is done. If they are the same size,
3240nothing is done (<i>no-op cast</i>).</p>
3241
3242<h5>Example:</h5>
3243<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3244 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3245 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3246 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3247</pre>
3248</div>
3249
3250<!-- _______________________________________________________________________ -->
3251<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3252 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3253</div>
3254<div class="doc_text">
3255
3256<h5>Syntax:</h5>
3257<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3258 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3259</pre>
3260
3261<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3262<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3263<tt>ty2</tt> without changing any bits.</p>
3264
3265<h5>Arguments:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3266<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3267a first class value, and a type to cast it to, which must also be a <a
3268 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencere3db84c2007-01-09 20:08:58 +0000[diff] [blame]3269and the destination type, <tt>ty2</tt>, must be identical. If the source
3270type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3271
3272<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3273<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3274<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3275this conversion. The conversion is done as if the <tt>value</tt> had been
3276stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3277converted to other pointer types with this instruction. To convert pointers to
3278other types, use the <a href="#i_inttoptr">inttoptr</a> or
3279<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3280
3281<h5>Example:</h5>
3282<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3283 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3284 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3285 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3286</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3287</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3288
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3289<!-- ======================================================================= -->
3290<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3291<div class="doc_text">
3292<p>The instructions in this category are the "miscellaneous"
3293instructions, which defy better classification.</p>
3294</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3295
3296<!-- _______________________________________________________________________ -->
3297<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3298</div>
3299<div class="doc_text">
3300<h5>Syntax:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3301<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3302</pre>
3303<h5>Overview:</h5>
3304<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3305of its two integer operands.</p>
3306<h5>Arguments:</h5>
3307<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3308the condition code indicating the kind of comparison to perform. It is not
3309a value, just a keyword. The possible condition code are:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3310<ol>
3311 <li><tt>eq</tt>: equal</li>
3312 <li><tt>ne</tt>: not equal </li>
3313 <li><tt>ugt</tt>: unsigned greater than</li>
3314 <li><tt>uge</tt>: unsigned greater or equal</li>
3315 <li><tt>ult</tt>: unsigned less than</li>
3316 <li><tt>ule</tt>: unsigned less or equal</li>
3317 <li><tt>sgt</tt>: signed greater than</li>
3318 <li><tt>sge</tt>: signed greater or equal</li>
3319 <li><tt>slt</tt>: signed less than</li>
3320 <li><tt>sle</tt>: signed less or equal</li>
3321</ol>
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3322<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3323<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3324<h5>Semantics:</h5>
3325<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3326the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3327yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3328<ol>
3329 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3330 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3331 </li>
3332 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3333 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3334 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3335 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3336 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3337 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3338 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3339 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3340 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3341 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3342 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3343 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3344 <li><tt>sge</tt>: interprets the operands as signed values and yields
3345 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3346 <li><tt>slt</tt>: interprets the operands as signed values and yields
3347 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3348 <li><tt>sle</tt>: interprets the operands as signed values and yields
3349 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3350</ol>
3351<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3352values are compared as if they were integers.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3353
3354<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3355<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3356 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3357 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3358 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3359 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3360 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3361</pre>
3362</div>
3363
3364<!-- _______________________________________________________________________ -->
3365<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3366</div>
3367<div class="doc_text">
3368<h5>Syntax:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3369<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3370</pre>
3371<h5>Overview:</h5>
3372<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3373of its floating point operands.</p>
3374<h5>Arguments:</h5>
3375<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3376the condition code indicating the kind of comparison to perform. It is not
3377a value, just a keyword. The possible condition code are:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3378<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3379 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3380 <li><tt>oeq</tt>: ordered and equal</li>
3381 <li><tt>ogt</tt>: ordered and greater than </li>
3382 <li><tt>oge</tt>: ordered and greater than or equal</li>
3383 <li><tt>olt</tt>: ordered and less than </li>
3384 <li><tt>ole</tt>: ordered and less than or equal</li>
3385 <li><tt>one</tt>: ordered and not equal</li>
3386 <li><tt>ord</tt>: ordered (no nans)</li>
3387 <li><tt>ueq</tt>: unordered or equal</li>
3388 <li><tt>ugt</tt>: unordered or greater than </li>
3389 <li><tt>uge</tt>: unordered or greater than or equal</li>
3390 <li><tt>ult</tt>: unordered or less than </li>
3391 <li><tt>ule</tt>: unordered or less than or equal</li>
3392 <li><tt>une</tt>: unordered or not equal</li>
3393 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3394 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3395</ol>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3396<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer02e0d1d2006-12-06 07:08:07 +0000[diff] [blame]3397<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3398<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3399<a href="#t_floating">floating point</a> typed. They must have identical
3400types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3401<h5>Semantics:</h5>
3402<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3403the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3404yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3405<ol>
3406 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3407 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3408 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3409 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3410 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3411 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3412 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3413 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3414 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3415 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3416 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3417 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3418 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3419 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3420 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3421 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3422 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3423 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3424 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3425 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3426 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3427 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3428 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3429 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3430 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3431 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3432 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3433 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3434</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3435
3436<h5>Example:</h5>
3437<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3438 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3439 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3440 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3441</pre>
3442</div>
3443
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3444<!-- _______________________________________________________________________ -->
3445<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3446Instruction</a> </div>
3447<div class="doc_text">
3448<h5>Syntax:</h5>
3449<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3450<h5>Overview:</h5>
3451<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3452the SSA graph representing the function.</p>
3453<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3454<p>The type of the incoming values is specified with the first type
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3455field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3456as arguments, with one pair for each predecessor basic block of the
3457current block. Only values of <a href="#t_firstclass">first class</a>
3458type may be used as the value arguments to the PHI node. Only labels
3459may be used as the label arguments.</p>
3460<p>There must be no non-phi instructions between the start of a basic
3461block and the PHI instructions: i.e. PHI instructions must be first in
3462a basic block.</p>
3463<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3464<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
3465specified by the pair corresponding to the predecessor basic block that executed
3466just prior to the current block.</p>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3467<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3468<pre>Loop: ; Infinite loop that counts from 0 on up...<br> %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]<br> %nextindvar = add i32 %indvar, 1<br> br label %Loop<br></pre>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3469</div>
3470
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3471<!-- _______________________________________________________________________ -->
3472<div class="doc_subsubsection">
3473 <a name="i_select">'<tt>select</tt>' Instruction</a>
3474</div>
3475
3476<div class="doc_text">
3477
3478<h5>Syntax:</h5>
3479
3480<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3481 &lt;result&gt; = select i1 &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3482</pre>
3483
3484<h5>Overview:</h5>
3485
3486<p>
3487The '<tt>select</tt>' instruction is used to choose one value based on a
3488condition, without branching.
3489</p>
3490
3491
3492<h5>Arguments:</h5>
3493
3494<p>
3495The '<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.
3496</p>
3497
3498<h5>Semantics:</h5>
3499
3500<p>
3501If the boolean condition evaluates to true, the instruction returns the first
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3502value argument; otherwise, it returns the second value argument.
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3503</p>
3504
3505<h5>Example:</h5>
3506
3507<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3508 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3509</pre>
3510</div>
3511
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]3512
3513<!-- _______________________________________________________________________ -->
3514<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3515 <a name="i_call">'<tt>call</tt>' Instruction</a>
3516</div>
3517
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3518<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3519
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3520<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3521<pre>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3522 &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]3523</pre>
3524
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3525<h5>Overview:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3526
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3527<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3528
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3529<h5>Arguments:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3530
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3531<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3532
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3533<ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3534 <li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3535 <p>The optional "tail" marker indicates whether the callee function accesses
3536 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3537 function call is eligible for tail call optimization. Note that calls may
3538 be marked "tail" even if they do not occur before a <a
3539 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3540 </li>
3541 <li>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3542 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3543 convention</a> the call should use. If none is specified, the call defaults
3544 to using C calling conventions.
3545 </li>
3546 <li>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3547 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
3548 being invoked. The argument types must match the types implied by this
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3549 signature. This type can be omitted if the function is not varargs and
3550 if the function type does not return a pointer to a function.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3551 </li>
3552 <li>
3553 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3554 be invoked. In most cases, this is a direct function invocation, but
3555 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3556 to function value.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3557 </li>
3558 <li>
3559 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencerd845d162005-05-01 22:22:57 +0000[diff] [blame]3560 function signature argument types. All arguments must be of
3561 <a href="#t_firstclass">first class</a> type. If the function signature
3562 indicates the function accepts a variable number of arguments, the extra
3563 arguments can be specified.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3564 </li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3565</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3566
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3567<h5>Semantics:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3568
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3569<p>The '<tt>call</tt>' instruction is used to cause control flow to
3570transfer to a specified function, with its incoming arguments bound to
3571the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3572instruction in the called function, control flow continues with the
3573instruction after the function call, and the return value of the
3574function is bound to the result argument. This is a simpler case of
3575the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3576
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3577<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3578
3579<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3580 %retval = call i32 %test(i32 %argc)
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3581 call i32(i8 *, ...) *%printf(i8 * %msg, i32 12, i8 42);
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3582 %X = tail call i32 %foo()
3583 %Y = tail call <a href="#callingconv">fastcc</a> i32 %foo()
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3584</pre>
3585
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3586</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3587
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3588<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3589<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]3590 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3591</div>
3592
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3593<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3594
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3595<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3596
3597<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3598 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3599</pre>
3600
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3601<h5>Overview:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3602
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3603<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3604the "variable argument" area of a function call. It is used to implement the
3605<tt>va_arg</tt> macro in C.</p>
3606
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3607<h5>Arguments:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3608
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3609<p>This instruction takes a <tt>va_list*</tt> value and the type of
3610the argument. It returns a value of the specified argument type and
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3611increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3612actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3613
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3614<h5>Semantics:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3615
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3616<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3617type from the specified <tt>va_list</tt> and causes the
3618<tt>va_list</tt> to point to the next argument. For more information,
3619see the variable argument handling <a href="#int_varargs">Intrinsic
3620Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3621
3622<p>It is legal for this instruction to be called in a function which does not
3623take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3624function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3625
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3626<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3627href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3628argument.</p>
3629
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3630<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3631
3632<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3633
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3634</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3635
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3636<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3637<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3638<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3639
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3640<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3641
3642<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]3643well known names and semantics and are required to follow certain restrictions.
3644Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3645language that does not require changing all of the transformations in LLVM when
3646adding to the language (or the bytecode reader/writer, the parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3647
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3648<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3649prefix is reserved in LLVM for intrinsic names; thus, function names may not
3650begin with this prefix. Intrinsic functions must always be external functions:
3651you cannot define the body of intrinsic functions. Intrinsic functions may
3652only be used in call or invoke instructions: it is illegal to take the address
3653of an intrinsic function. Additionally, because intrinsic functions are part
3654of the LLVM language, it is required if any are added that they be documented
3655here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3656
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3657<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]3658a family of functions that perform the same operation but on different data
3659types. This is most frequent with the integer types. Since LLVM can represent
3660over 8 million different integer types, there is a way to declare an intrinsic
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3661that can be overloaded based on its arguments. Such an intrinsic will have the
3662names of its argument types encoded into its function name, each
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]3663preceded by a period. For example, the <tt>llvm.ctpop</tt> function can take an
3664integer of any width. This leads to a family of functions such as
3665<tt>i32 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i32 @llvm.ctpop.i29(i29 %val)</tt>.
3666</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3667
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]3668
3669<p>To learn how to add an intrinsic function, please see the
3670<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3671</p>
3672
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3673</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3674
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3675<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3676<div class="doc_subsection">
3677 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3678</div>
3679
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3680<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3681
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3682<p>Variable argument support is defined in LLVM with the <a
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]3683 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3684intrinsic functions. These functions are related to the similarly
3685named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3686
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3687<p>All of these functions operate on arguments that use a
3688target-specific value type "<tt>va_list</tt>". The LLVM assembly
3689language reference manual does not define what this type is, so all
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3690transformations should be prepared to handle these functions regardless of
3691the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3692
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]3693<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3694instruction and the variable argument handling intrinsic functions are
3695used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3696
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3697<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3698define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3699 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3700 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3701 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3702 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3703
3704 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3705 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3706
3707 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3708 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3709 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3710 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3711 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3712
3713 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3714 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3715 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3716}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3717
3718declare void @llvm.va_start(i8*)
3719declare void @llvm.va_copy(i8*, i8*)
3720declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3721</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3722</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3723
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3724<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3725<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3726 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3727</div>
3728
3729
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3730<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3731<h5>Syntax:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3732<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3733<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3734<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3735<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3736href="#i_va_arg">va_arg</a></tt>.</p>
3737
3738<h5>Arguments:</h5>
3739
3740<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3741
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3742<h5>Semantics:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3743
3744<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3745macro available in C. In a target-dependent way, it initializes the
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3746<tt>va_list</tt> element to which the argument points, so that the next call to
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3747<tt>va_arg</tt> will produce the first variable argument passed to the function.
3748Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3749last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3750
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3751</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3752
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3753<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3754<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3755 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3756</div>
3757
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3758<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3759<h5>Syntax:</h5>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3760<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3761<h5>Overview:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3762
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3763<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3764which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3765or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3766
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3767<h5>Arguments:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3768
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3769<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3770
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3771<h5>Semantics:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3772
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3773<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3774macro available in C. In a target-dependent way, it destroys the
3775<tt>va_list</tt> element to which the argument points. Calls to <a
3776href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
3777<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
3778<tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3779
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3780</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3781
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3782<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3783<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3784 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3785</div>
3786
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3787<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3788
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3789<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3790
3791<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3792 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3793</pre>
3794
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3795<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3796
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3797<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
3798from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3799
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3800<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3801
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3802<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Andrew Lenharth5305ea52005-06-22 20:38:11 +0000[diff] [blame]3803The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3804
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3805
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3806<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3807
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3808<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
3809macro available in C. In a target-dependent way, it copies the source
3810<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
3811intrinsic is necessary because the <tt><a href="#int_va_start">
3812llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
3813example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3814
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3815</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3816
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3817<!-- ======================================================================= -->
3818<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3819 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3820</div>
3821
3822<div class="doc_text">
3823
3824<p>
3825LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3826Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3827These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3828stack</a>, as well as garbage collector implementations that require <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3829href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3830Front-ends for type-safe garbage collected languages should generate these
3831intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3832href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3833</p>
3834</div>
3835
3836<!-- _______________________________________________________________________ -->
3837<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3838 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3839</div>
3840
3841<div class="doc_text">
3842
3843<h5>Syntax:</h5>
3844
3845<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3846 declare void @llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3847</pre>
3848
3849<h5>Overview:</h5>
3850
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]3851<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]3852the code generator, and allows some metadata to be associated with it.</p>
3853
3854<h5>Arguments:</h5>
3855
3856<p>The first argument specifies the address of a stack object that contains the
3857root pointer. The second pointer (which must be either a constant or a global
3858value address) contains the meta-data to be associated with the root.</p>
3859
3860<h5>Semantics:</h5>
3861
3862<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3863location. At compile-time, the code generator generates information to allow
3864the runtime to find the pointer at GC safe points.
3865</p>
3866
3867</div>
3868
3869
3870<!-- _______________________________________________________________________ -->
3871<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3872 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3873</div>
3874
3875<div class="doc_text">
3876
3877<h5>Syntax:</h5>
3878
3879<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3880 declare i8 * @llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3881</pre>
3882
3883<h5>Overview:</h5>
3884
3885<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3886locations, allowing garbage collector implementations that require read
3887barriers.</p>
3888
3889<h5>Arguments:</h5>
3890
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]3891<p>The second argument is the address to read from, which should be an address
3892allocated from the garbage collector. The first object is a pointer to the
3893start of the referenced object, if needed by the language runtime (otherwise
3894null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3895
3896<h5>Semantics:</h5>
3897
3898<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3899instruction, but may be replaced with substantially more complex code by the
3900garbage collector runtime, as needed.</p>
3901
3902</div>
3903
3904
3905<!-- _______________________________________________________________________ -->
3906<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3907 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3908</div>
3909
3910<div class="doc_text">
3911
3912<h5>Syntax:</h5>
3913
3914<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3915 declare void @llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3916</pre>
3917
3918<h5>Overview:</h5>
3919
3920<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3921locations, allowing garbage collector implementations that require write
3922barriers (such as generational or reference counting collectors).</p>
3923
3924<h5>Arguments:</h5>
3925
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]3926<p>The first argument is the reference to store, the second is the start of the
3927object to store it to, and the third is the address of the field of Obj to
3928store to. If the runtime does not require a pointer to the object, Obj may be
3929null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3930
3931<h5>Semantics:</h5>
3932
3933<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3934instruction, but may be replaced with substantially more complex code by the
3935garbage collector runtime, as needed.</p>
3936
3937</div>
3938
3939
3940
3941<!-- ======================================================================= -->
3942<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3943 <a name="int_codegen">Code Generator Intrinsics</a>
3944</div>
3945
3946<div class="doc_text">
3947<p>
3948These intrinsics are provided by LLVM to expose special features that may only
3949be implemented with code generator support.
3950</p>
3951
3952</div>
3953
3954<!-- _______________________________________________________________________ -->
3955<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3956 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3957</div>
3958
3959<div class="doc_text">
3960
3961<h5>Syntax:</h5>
3962<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3963 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3964</pre>
3965
3966<h5>Overview:</h5>
3967
3968<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]3969The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
3970target-specific value indicating the return address of the current function
3971or one of its callers.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3972</p>
3973
3974<h5>Arguments:</h5>
3975
3976<p>
3977The argument to this intrinsic indicates which function to return the address
3978for. Zero indicates the calling function, one indicates its caller, etc. The
3979argument is <b>required</b> to be a constant integer value.
3980</p>
3981
3982<h5>Semantics:</h5>
3983
3984<p>
3985The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
3986the return address of the specified call frame, or zero if it cannot be
3987identified. The value returned by this intrinsic is likely to be incorrect or 0
3988for arguments other than zero, so it should only be used for debugging purposes.
3989</p>
3990
3991<p>
3992Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]3993aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3994source-language caller.
3995</p>
3996</div>
3997
3998
3999<!-- _______________________________________________________________________ -->
4000<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4001 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4002</div>
4003
4004<div class="doc_text">
4005
4006<h5>Syntax:</h5>
4007<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4008 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4009</pre>
4010
4011<h5>Overview:</h5>
4012
4013<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]4014The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4015target-specific frame pointer value for the specified stack frame.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4016</p>
4017
4018<h5>Arguments:</h5>
4019
4020<p>
4021The argument to this intrinsic indicates which function to return the frame
4022pointer for. Zero indicates the calling function, one indicates its caller,
4023etc. The argument is <b>required</b> to be a constant integer value.
4024</p>
4025
4026<h5>Semantics:</h5>
4027
4028<p>
4029The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4030the frame address of the specified call frame, or zero if it cannot be
4031identified. The value returned by this intrinsic is likely to be incorrect or 0
4032for arguments other than zero, so it should only be used for debugging purposes.
4033</p>
4034
4035<p>
4036Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]4037aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4038source-language caller.
4039</p>
4040</div>
4041
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4042<!-- _______________________________________________________________________ -->
4043<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4044 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4045</div>
4046
4047<div class="doc_text">
4048
4049<h5>Syntax:</h5>
4050<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4051 declare i8 *@llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4052</pre>
4053
4054<h5>Overview:</h5>
4055
4056<p>
4057The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4058the function stack, for use with <a href="#int_stackrestore">
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4059<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4060features like scoped automatic variable sized arrays in C99.
4061</p>
4062
4063<h5>Semantics:</h5>
4064
4065<p>
4066This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4067href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4068<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4069<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4070state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4071practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4072that were allocated after the <tt>llvm.stacksave</tt> was executed.
4073</p>
4074
4075</div>
4076
4077<!-- _______________________________________________________________________ -->
4078<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4079 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4080</div>
4081
4082<div class="doc_text">
4083
4084<h5>Syntax:</h5>
4085<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4086 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4087</pre>
4088
4089<h5>Overview:</h5>
4090
4091<p>
4092The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4093the function stack to the state it was in when the corresponding <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4094href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4095useful for implementing language features like scoped automatic variable sized
4096arrays in C99.
4097</p>
4098
4099<h5>Semantics:</h5>
4100
4101<p>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4102See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4103</p>
4104
4105</div>
4106
4107
4108<!-- _______________________________________________________________________ -->
4109<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4110 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4111</div>
4112
4113<div class="doc_text">
4114
4115<h5>Syntax:</h5>
4116<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4117 declare void @llvm.prefetch(i8 * &lt;address&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4118 i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4119</pre>
4120
4121<h5>Overview:</h5>
4122
4123
4124<p>
4125The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4126a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4127no
4128effect on the behavior of the program but can change its performance
Chris Lattnerff851072005-02-28 19:47:14 +0000[diff] [blame]4129characteristics.
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4130</p>
4131
4132<h5>Arguments:</h5>
4133
4134<p>
4135<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4136determining if the fetch should be for a read (0) or write (1), and
4137<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattnerd3e641c2005-03-07 20:31:38 +0000[diff] [blame]4138locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4139<tt>locality</tt> arguments must be constant integers.
4140</p>
4141
4142<h5>Semantics:</h5>
4143
4144<p>
4145This intrinsic does not modify the behavior of the program. In particular,
4146prefetches cannot trap and do not produce a value. On targets that support this
4147intrinsic, the prefetch can provide hints to the processor cache for better
4148performance.
4149</p>
4150
4151</div>
4152
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4153<!-- _______________________________________________________________________ -->
4154<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4155 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4156</div>
4157
4158<div class="doc_text">
4159
4160<h5>Syntax:</h5>
4161<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4162 declare void @llvm.pcmarker( i32 &lt;id&gt; )
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4163</pre>
4164
4165<h5>Overview:</h5>
4166
4167
4168<p>
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4169The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4170(PC) in a region of
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4171code to simulators and other tools. The method is target specific, but it is
4172expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohendc6bfea2005-11-11 02:15:27 +0000[diff] [blame]4173The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnere64d41d2005-11-15 06:07:55 +0000[diff] [blame]4174after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb40261e2006-03-24 07:16:10 +0000[diff] [blame]4175optimizations. The intended use is to be inserted after optimizations to allow
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4176correlations of simulation runs.
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4177</p>
4178
4179<h5>Arguments:</h5>
4180
4181<p>
4182<tt>id</tt> is a numerical id identifying the marker.
4183</p>
4184
4185<h5>Semantics:</h5>
4186
4187<p>
4188This intrinsic does not modify the behavior of the program. Backends that do not
4189support this intrinisic may ignore it.
4190</p>
4191
4192</div>
4193
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4194<!-- _______________________________________________________________________ -->
4195<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4196 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4197</div>
4198
4199<div class="doc_text">
4200
4201<h5>Syntax:</h5>
4202<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4203 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4204</pre>
4205
4206<h5>Overview:</h5>
4207
4208
4209<p>
4210The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4211counter register (or similar low latency, high accuracy clocks) on those targets
4212that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4213As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4214should only be used for small timings.
4215</p>
4216
4217<h5>Semantics:</h5>
4218
4219<p>
4220When directly supported, reading the cycle counter should not modify any memory.
4221Implementations are allowed to either return a application specific value or a
4222system wide value. On backends without support, this is lowered to a constant 0.
4223</p>
4224
4225</div>
4226
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4227<!-- ======================================================================= -->
4228<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4229 <a name="int_libc">Standard C Library Intrinsics</a>
4230</div>
4231
4232<div class="doc_text">
4233<p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4234LLVM provides intrinsics for a few important standard C library functions.
4235These intrinsics allow source-language front-ends to pass information about the
4236alignment of the pointer arguments to the code generator, providing opportunity
4237for more efficient code generation.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4238</p>
4239
4240</div>
4241
4242<!-- _______________________________________________________________________ -->
4243<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4244 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4245</div>
4246
4247<div class="doc_text">
4248
4249<h5>Syntax:</h5>
4250<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4251 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4252 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4253 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4254 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4255</pre>
4256
4257<h5>Overview:</h5>
4258
4259<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4260The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4261location to the destination location.
4262</p>
4263
4264<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4265Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4266intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4267</p>
4268
4269<h5>Arguments:</h5>
4270
4271<p>
4272The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4273the source. The third argument is an integer argument
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4274specifying the number of bytes to copy, and the fourth argument is the alignment
4275of the source and destination locations.
4276</p>
4277
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4278<p>
4279If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattner5316e5d2006-03-04 00:02:10 +0000[diff] [blame]4280the caller guarantees that both the source and destination pointers are aligned
4281to that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4282</p>
4283
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4284<h5>Semantics:</h5>
4285
4286<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4287The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4288location to the destination location, which are not allowed to overlap. It
4289copies "len" bytes of memory over. If the argument is known to be aligned to
4290some boundary, this can be specified as the fourth argument, otherwise it should
4291be set to 0 or 1.
4292</p>
4293</div>
4294
4295
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4296<!-- _______________________________________________________________________ -->
4297<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4298 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4299</div>
4300
4301<div class="doc_text">
4302
4303<h5>Syntax:</h5>
4304<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4305 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4306 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4307 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4308 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4309</pre>
4310
4311<h5>Overview:</h5>
4312
4313<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4314The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4315location to the destination location. It is similar to the
4316'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4317</p>
4318
4319<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4320Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4321intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4322</p>
4323
4324<h5>Arguments:</h5>
4325
4326<p>
4327The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4328the source. The third argument is an integer argument
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4329specifying the number of bytes to copy, and the fourth argument is the alignment
4330of the source and destination locations.
4331</p>
4332
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4333<p>
4334If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattner5316e5d2006-03-04 00:02:10 +0000[diff] [blame]4335the caller guarantees that the source and destination pointers are aligned to
4336that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4337</p>
4338
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4339<h5>Semantics:</h5>
4340
4341<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4342The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4343location to the destination location, which may overlap. It
4344copies "len" bytes of memory over. If the argument is known to be aligned to
4345some boundary, this can be specified as the fourth argument, otherwise it should
4346be set to 0 or 1.
4347</p>
4348</div>
4349
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4350
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4351<!-- _______________________________________________________________________ -->
4352<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4353 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4354</div>
4355
4356<div class="doc_text">
4357
4358<h5>Syntax:</h5>
4359<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4360 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4361 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4362 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4363 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4364</pre>
4365
4366<h5>Overview:</h5>
4367
4368<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4369The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4370byte value.
4371</p>
4372
4373<p>
4374Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4375does not return a value, and takes an extra alignment argument.
4376</p>
4377
4378<h5>Arguments:</h5>
4379
4380<p>
4381The first argument is a pointer to the destination to fill, the second is the
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4382byte value to fill it with, the third argument is an integer
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4383argument specifying the number of bytes to fill, and the fourth argument is the
4384known alignment of destination location.
4385</p>
4386
4387<p>
4388If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattner5316e5d2006-03-04 00:02:10 +0000[diff] [blame]4389the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4390</p>
4391
4392<h5>Semantics:</h5>
4393
4394<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4395The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4396the
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4397destination location. If the argument is known to be aligned to some boundary,
4398this can be specified as the fourth argument, otherwise it should be set to 0 or
43991.
4400</p>
4401</div>
4402
4403
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]4404<!-- _______________________________________________________________________ -->
4405<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4406 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4407</div>
4408
4409<div class="doc_text">
4410
4411<h5>Syntax:</h5>
4412<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4413 declare float @llvm.sqrt.f32(float %Val)
4414 declare double @llvm.sqrt.f64(double %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4415</pre>
4416
4417<h5>Overview:</h5>
4418
4419<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4420The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4421returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
4422<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4423negative numbers (which allows for better optimization).
4424</p>
4425
4426<h5>Arguments:</h5>
4427
4428<p>
4429The argument and return value are floating point numbers of the same type.
4430</p>
4431
4432<h5>Semantics:</h5>
4433
4434<p>
4435This function returns the sqrt of the specified operand if it is a positive
4436floating point number.
4437</p>
4438</div>
4439
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4440<!-- _______________________________________________________________________ -->
4441<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4442 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4443</div>
4444
4445<div class="doc_text">
4446
4447<h5>Syntax:</h5>
4448<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4449 declare float @llvm.powi.f32(float %Val, i32 %power)
4450 declare double @llvm.powi.f64(double %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4451</pre>
4452
4453<h5>Overview:</h5>
4454
4455<p>
4456The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4457specified (positive or negative) power. The order of evaluation of
4458multiplications is not defined.
4459</p>
4460
4461<h5>Arguments:</h5>
4462
4463<p>
4464The second argument is an integer power, and the first is a value to raise to
4465that power.
4466</p>
4467
4468<h5>Semantics:</h5>
4469
4470<p>
4471This function returns the first value raised to the second power with an
4472unspecified sequence of rounding operations.</p>
4473</div>
4474
4475
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4476<!-- ======================================================================= -->
4477<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4478 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4479</div>
4480
4481<div class="doc_text">
4482<p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4483LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4484These allow efficient code generation for some algorithms.
4485</p>
4486
4487</div>
4488
4489<!-- _______________________________________________________________________ -->
4490<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4491 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4492</div>
4493
4494<div class="doc_text">
4495
4496<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4497<p>This is an overloaded intrinsic function. You can use bswap on any integer
4498type that is an even number of bytes (i.e. BitWidth % 16 == 0). Note the suffix
4499that includes the type for the result and the operand.
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4500<pre>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4501 declare i16 @llvm.bswap.i16.i16(i16 &lt;id&gt;)
4502 declare i32 @llvm.bswap.i32.i32(i32 &lt;id&gt;)
Reid Spencer403a1c42007-04-02 00:19:52 +0000[diff] [blame]4503 declare i64 @llvm.bswap.i64.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4504</pre>
4505
4506<h5>Overview:</h5>
4507
4508<p>
Reid Spencerf361c4f2007-04-02 02:25:19 +0000[diff] [blame]4509The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4510values with an even number of bytes (positive multiple of 16 bits). These are
4511useful for performing operations on data that is not in the target's native
4512byte order.
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4513</p>
4514
4515<h5>Semantics:</h5>
4516
4517<p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4518The <tt>llvm.bswap.16.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4519and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4520intrinsic returns an i32 value that has the four bytes of the input i32
4521swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4522i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48.i48</tt>,
4523<tt>llvm.bswap.i64.i64</tt> and other intrinsics extend this concept to
4524additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4525</p>
4526
4527</div>
4528
4529<!-- _______________________________________________________________________ -->
4530<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4531 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4532</div>
4533
4534<div class="doc_text">
4535
4536<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4537<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
4538width. Not all targets support all bit widths however.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4539<pre>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4540 declare i32 @llvm.ctpop.i8 (i8 &lt;src&gt;)
4541 declare i32 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4542 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4543 declare i32 @llvm.ctpop.i64(i64 &lt;src&gt;)
4544 declare i32 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4545</pre>
4546
4547<h5>Overview:</h5>
4548
4549<p>
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]4550The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4551value.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4552</p>
4553
4554<h5>Arguments:</h5>
4555
4556<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]4557The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]4558integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4559</p>
4560
4561<h5>Semantics:</h5>
4562
4563<p>
4564The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4565</p>
4566</div>
4567
4568<!-- _______________________________________________________________________ -->
4569<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]4570 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4571</div>
4572
4573<div class="doc_text">
4574
4575<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4576<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
4577integer bit width. Not all targets support all bit widths however.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4578<pre>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4579 declare i32 @llvm.ctlz.i8 (i8 &lt;src&gt;)
4580 declare i32 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4581 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4582 declare i32 @llvm.ctlz.i64(i64 &lt;src&gt;)
4583 declare i32 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4584</pre>
4585
4586<h5>Overview:</h5>
4587
4588<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4589The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4590leading zeros in a variable.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4591</p>
4592
4593<h5>Arguments:</h5>
4594
4595<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]4596The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]4597integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4598</p>
4599
4600<h5>Semantics:</h5>
4601
4602<p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4603The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4604in a variable. If the src == 0 then the result is the size in bits of the type
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4605of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4606</p>
4607</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]4608
4609
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4610
4611<!-- _______________________________________________________________________ -->
4612<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]4613 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4614</div>
4615
4616<div class="doc_text">
4617
4618<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4619<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
4620integer bit width. Not all targets support all bit widths however.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4621<pre>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4622 declare i32 @llvm.cttz.i8 (i8 &lt;src&gt;)
4623 declare i32 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4624 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4625 declare i32 @llvm.cttz.i64(i64 &lt;src&gt;)
4626 declare i32 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4627</pre>
4628
4629<h5>Overview:</h5>
4630
4631<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4632The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4633trailing zeros.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4634</p>
4635
4636<h5>Arguments:</h5>
4637
4638<p>
4639The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]4640integer type. The return type must match the argument type.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4641</p>
4642
4643<h5>Semantics:</h5>
4644
4645<p>
4646The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4647in a variable. If the src == 0 then the result is the size in bits of the type
4648of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4649</p>
4650</div>
4651
Reid Spencer8a5799f2007-04-01 08:27:01 +0000[diff] [blame]4652<!-- _______________________________________________________________________ -->
4653<div class="doc_subsubsection">
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]4654 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]4655</div>
4656
4657<div class="doc_text">
4658
4659<h5>Syntax:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]4660<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]4661on any integer bit width.
4662<pre>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]4663 declare i17 @llvm.part.select.i17.i17 (i17 %val, i32 %loBit, i32 %hiBit)
4664 declare i29 @llvm.part.select.i29.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]4665</pre>
4666
4667<h5>Overview:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]4668<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]4669range of bits from an integer value and returns them in the same bit width as
4670the original value.</p>
4671
4672<h5>Arguments:</h5>
4673<p>The first argument, <tt>%val</tt> and the result may be integer types of
4674any bit width but they must have the same bit width. The second and third
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4675arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]4676
4677<h5>Semantics:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]4678<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4679of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
4680<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
4681operates in forward mode.</p>
4682<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
4683right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]4684only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
4685<ol>
4686 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
4687 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
4688 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
4689 to determine the number of bits to retain.</li>
4690 <li>A mask of the retained bits is created by shifting a -1 value.</li>
4691 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
4692</ol>
Reid Spencer70845c02007-05-14 16:14:57 +0000[diff] [blame]4693<p>In reverse mode, a similar computation is made except that the bits are
4694returned in the reverse order. So, for example, if <tt>X</tt> has the value
4695<tt>i16 0x0ACF (101011001111)</tt> and we apply
4696<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
4697<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]4698</div>
4699
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]4700<div class="doc_subsubsection">
4701 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
4702</div>
4703
4704<div class="doc_text">
4705
4706<h5>Syntax:</h5>
4707<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
4708on any integer bit width.
4709<pre>
4710 declare i17 @llvm.part.set.i17.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
4711 declare i29 @llvm.part.set.i29.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi)
4712</pre>
4713
4714<h5>Overview:</h5>
4715<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
4716of bits in an integer value with another integer value. It returns the integer
4717with the replaced bits.</p>
4718
4719<h5>Arguments:</h5>
4720<p>The first argument, <tt>%val</tt> and the result may be integer types of
4721any bit width but they must have the same bit width. <tt>%val</tt> is the value
4722whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
4723integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
4724type since they specify only a bit index.</p>
4725
4726<h5>Semantics:</h5>
4727<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
4728of operation: forwards and reverse. If <tt>%lo</tt> is greater than
4729<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
4730operates in forward mode.</p>
4731<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
4732truncating it down to the size of the replacement area or zero extending it
4733up to that size.</p>
4734<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
4735are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
4736in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
4737to the <tt>%hi</tt>th bit.
Reid Spencer146281c2007-05-14 16:50:20 +0000[diff] [blame]4738<p>In reverse mode, a similar computation is made except that the bits are
4739reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
4740<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]4741<h5>Examples:</h5>
4742<pre>
Reid Spencerc70afc32007-04-12 01:03:03 +0000[diff] [blame]4743 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencer146281c2007-05-14 16:50:20 +0000[diff] [blame]4744 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
4745 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
4746 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerc70afc32007-04-12 01:03:03 +0000[diff] [blame]4747 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]4748</pre>
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]4749</div>
4750
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4751<!-- ======================================================================= -->
4752<div class="doc_subsection">
4753 <a name="int_debugger">Debugger Intrinsics</a>
4754</div>
4755
4756<div class="doc_text">
4757<p>
4758The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4759are described in the <a
4760href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4761Debugging</a> document.
4762</p>
4763</div>
4764
4765
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]4766<!-- ======================================================================= -->
4767<div class="doc_subsection">
4768 <a name="int_eh">Exception Handling Intrinsics</a>
4769</div>
4770
4771<div class="doc_text">
4772<p> The LLVM exception handling intrinsics (which all start with
4773<tt>llvm.eh.</tt> prefix), are described in the <a
4774href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
4775Handling</a> document. </p>
4776</div>
4777
4778
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4779<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4780<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]4781<address>
4782 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
4783 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
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4785 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
4786
4787 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]4788 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]4789 Last modified: $Date$
4790</address>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4791</body>
4792</html>