Gitiles
Code Review Sign In
gerrit-public.fairphone.software / toolchain / llvm-project / db94353bff8182a7f4882030586c5230c2c3588c / . / llvm / docs / LangRef.html
blob: 0c004e48251497d993559f5de6ab2ca6ef663259 [file] [log] [blame]
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
2 "http://www.w3.org/TR/html4/strict.dtd">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3<html>
4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
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>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]27 <li><a href="#paramattrs">Parameter Attributes</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]28 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]29 </ol>
30 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]31 <li><a href="#typesystem">Type System</a>
32 <ol>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]33 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]34 <ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]35 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]36 </ol>
37 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]38 <li><a href="#t_derived">Derived Types</a>
39 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]40 <li><a href="#t_array">Array Type</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]41 <li><a href="#t_function">Function Type</a></li>
42 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]43 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]44 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]45 <li><a href="#t_packed">Packed Type</a></li>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]46 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]47 </ol>
48 </li>
49 </ol>
50 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]51 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]52 <ol>
53 <li><a href="#simpleconstants">Simple Constants</a>
54 <li><a href="#aggregateconstants">Aggregate Constants</a>
55 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
56 <li><a href="#undefvalues">Undefined Values</a>
57 <li><a href="#constantexprs">Constant Expressions</a>
58 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]59 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]60 <li><a href="#othervalues">Other Values</a>
61 <ol>
62 <li><a href="#inlineasm">Inline Assembler Expressions</a>
63 </ol>
64 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]65 <li><a href="#instref">Instruction Reference</a>
66 <ol>
67 <li><a href="#terminators">Terminator Instructions</a>
68 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]69 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
70 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]71 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
72 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]73 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]74 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]75 </ol>
76 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]77 <li><a href="#binaryops">Binary Operations</a>
78 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]79 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
80 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
81 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]82 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
83 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
84 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]85 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
86 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
87 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]88 </ol>
89 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]90 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
91 <ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]92 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]93 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]94 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
95 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]96 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
97 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]98 </ol>
99 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]100 <li><a href="#vectorops">Vector Operations</a>
101 <ol>
102 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
103 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
104 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]105 </ol>
106 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]107 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]108 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]109 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
110 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
111 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]112 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
113 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
114 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]115 </ol>
116 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]117 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]118 <ol>
119 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
120 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
121 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
122 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
123 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]124 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
125 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
126 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
127 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]128 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
129 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]130 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]131 </ol>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]132 <li><a href="#otherops">Other Operations</a>
133 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]134 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
135 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]136 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]137 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]138 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]139 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]140 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]141 </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 Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]144 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]145 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]146 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
147 <ol>
148 <li><a href="#i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
149 <li><a href="#i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
150 <li><a href="#i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
151 </ol>
152 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]153 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
154 <ol>
155 <li><a href="#i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
156 <li><a href="#i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
157 <li><a href="#i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
158 </ol>
159 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]160 <li><a href="#int_codegen">Code Generator Intrinsics</a>
161 <ol>
162 <li><a href="#i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
163 <li><a href="#i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]164 <li><a href="#i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
165 <li><a href="#i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]166 <li><a href="#i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]167 <li><a href="#i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]168 <li><a href="#i_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]169 </ol>
170 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]171 <li><a href="#int_libc">Standard C Library Intrinsics</a>
172 <ol>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]173 <li><a href="#i_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
174 <li><a href="#i_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
175 <li><a href="#i_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]176 <li><a href="#i_isunordered">'<tt>llvm.isunordered.*</tt>' Intrinsic</a></li>
177 <li><a href="#i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]178 <li><a href="#i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]179 </ol>
180 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]181 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]182 <ol>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]183 <li><a href="#i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]184 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
185 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
186 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]187 </ol>
188 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]189 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]190 </ol>
191 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]192</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]193
194<div class="doc_author">
195 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
196 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]197</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]198
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]199<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]200<div class="doc_section"> <a name="abstract">Abstract </a></div>
201<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]202
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]203<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]204<p>This document is a reference manual for the LLVM assembly language.
205LLVM is an SSA based representation that provides type safety,
206low-level operations, flexibility, and the capability of representing
207'all' high-level languages cleanly. It is the common code
208representation used throughout all phases of the LLVM compilation
209strategy.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]210</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]211
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]212<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]213<div class="doc_section"> <a name="introduction">Introduction</a> </div>
214<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]215
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]216<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]217
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]218<p>The LLVM code representation is designed to be used in three
219different forms: as an in-memory compiler IR, as an on-disk bytecode
220representation (suitable for fast loading by a Just-In-Time compiler),
221and as a human readable assembly language representation. This allows
222LLVM to provide a powerful intermediate representation for efficient
223compiler transformations and analysis, while providing a natural means
224to debug and visualize the transformations. The three different forms
225of LLVM are all equivalent. This document describes the human readable
226representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]227
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]228<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]229while being expressive, typed, and extensible at the same time. It
230aims to be a "universal IR" of sorts, by being at a low enough level
231that high-level ideas may be cleanly mapped to it (similar to how
232microprocessors are "universal IR's", allowing many source languages to
233be mapped to them). By providing type information, LLVM can be used as
234the target of optimizations: for example, through pointer analysis, it
235can be proven that a C automatic variable is never accessed outside of
236the current function... allowing it to be promoted to a simple SSA
237value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]238
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]239</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]240
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]241<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]242<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]243
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]244<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]245
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]246<p>It is important to note that this document describes 'well formed'
247LLVM assembly language. There is a difference between what the parser
248accepts and what is considered 'well formed'. For example, the
249following instruction is syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]250
251<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]252 %x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]253</pre>
254
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]255<p>...because the definition of <tt>%x</tt> does not dominate all of
256its uses. The LLVM infrastructure provides a verification pass that may
257be used to verify that an LLVM module is well formed. This pass is
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]258automatically run by the parser after parsing input assembly and by
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]259the optimizer before it outputs bytecode. The violations pointed out
260by the verifier pass indicate bugs in transformation passes or input to
261the parser.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]262
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]263<!-- Describe the typesetting conventions here. --> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]264
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]265<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]266<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]267<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]268
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]269<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]270
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]271<p>LLVM uses three different forms of identifiers, for different
272purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]273
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]274<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]275 <li>Named values are represented as a string of characters with a '%' prefix.
276 For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
277 regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
278 Identifiers which require other characters in their names can be surrounded
279 with quotes. In this way, anything except a <tt>"</tt> character can be used
280 in a name.</li>
281
282 <li>Unnamed values are represented as an unsigned numeric value with a '%'
283 prefix. For example, %12, %2, %44.</li>
284
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]285 <li>Constants, which are described in a <a href="#constants">section about
286 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]287</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]288
289<p>LLVM requires that values start with a '%' sign for two reasons: Compilers
290don't need to worry about name clashes with reserved words, and the set of
291reserved words may be expanded in the future without penalty. Additionally,
292unnamed identifiers allow a compiler to quickly come up with a temporary
293variable without having to avoid symbol table conflicts.</p>
294
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]295<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]296languages. There are keywords for different opcodes
297('<tt><a href="#i_add">add</a></tt>',
298 '<tt><a href="#i_bitcast">bitcast</a></tt>',
299 '<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]300href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]301and others. These reserved words cannot conflict with variable names, because
302none of them start with a '%' character.</p>
303
304<p>Here is an example of LLVM code to multiply the integer variable
305'<tt>%X</tt>' by 8:</p>
306
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]307<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]308
309<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]310 %result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]311</pre>
312
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]313<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]314
315<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]316 %result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]317</pre>
318
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]319<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]320
321<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]322 <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
323 <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
324 %result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]325</pre>
326
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]327<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
328important lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]329
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]330<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]331
332 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
333 line.</li>
334
335 <li>Unnamed temporaries are created when the result of a computation is not
336 assigned to a named value.</li>
337
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]338 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]339
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]340</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]341
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]342<p>...and it also shows a convention that we follow in this document. When
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]343demonstrating instructions, we will follow an instruction with a comment that
344defines the type and name of value produced. Comments are shown in italic
345text.</p>
346
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]347</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]348
349<!-- *********************************************************************** -->
350<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
351<!-- *********************************************************************** -->
352
353<!-- ======================================================================= -->
354<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
355</div>
356
357<div class="doc_text">
358
359<p>LLVM programs are composed of "Module"s, each of which is a
360translation unit of the input programs. Each module consists of
361functions, global variables, and symbol table entries. Modules may be
362combined together with the LLVM linker, which merges function (and
363global variable) definitions, resolves forward declarations, and merges
364symbol table entries. Here is an example of the "hello world" module:</p>
365
366<pre><i>; Declare the string constant as a global constant...</i>
367<a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]368 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]369
370<i>; External declaration of the puts function</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]371<a href="#functionstructure">declare</a> i32 %puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]372
Chris Lattnerd2d29a02006-06-13 03:05:47 +0000[diff] [blame]373<i>; Global variable / Function body section separator</i>
374implementation
375
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]376<i>; Definition of main function</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]377define i32 %main() { <i>; i32()* </i>
378 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]379 %cast210 = <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]380 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]381
382 <i>; Call puts function to write out the string to stdout...</i>
383 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]384 href="#i_call">call</a> i32 %puts(i8 * %cast210) <i>; i32</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]385 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]386 href="#i_ret">ret</a> i32 0<br>}<br></pre>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]387
388<p>This example is made up of a <a href="#globalvars">global variable</a>
389named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
390function, and a <a href="#functionstructure">function definition</a>
391for "<tt>main</tt>".</p>
392
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]393<p>In general, a module is made up of a list of global values,
394where both functions and global variables are global values. Global values are
395represented by a pointer to a memory location (in this case, a pointer to an
396array of char, and a pointer to a function), and have one of the following <a
397href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]398
Chris Lattnerd2d29a02006-06-13 03:05:47 +0000[diff] [blame]399<p>Due to a limitation in the current LLVM assembly parser (it is limited by
400one-token lookahead), modules are split into two pieces by the "implementation"
401keyword. Global variable prototypes and definitions must occur before the
402keyword, and function definitions must occur after it. Function prototypes may
403occur either before or after it. In the future, the implementation keyword may
404become a noop, if the parser gets smarter.</p>
405
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]406</div>
407
408<!-- ======================================================================= -->
409<div class="doc_subsection">
410 <a name="linkage">Linkage Types</a>
411</div>
412
413<div class="doc_text">
414
415<p>
416All Global Variables and Functions have one of the following types of linkage:
417</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]418
419<dl>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]420
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]421 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]422
423 <dd>Global values with internal linkage are only directly accessible by
424 objects in the current module. In particular, linking code into a module with
425 an internal global value may cause the internal to be renamed as necessary to
426 avoid collisions. Because the symbol is internal to the module, all
427 references can be updated. This corresponds to the notion of the
428 '<tt>static</tt>' keyword in C, or the idea of "anonymous namespaces" in C++.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]429 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]430
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]431 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]432
433 <dd>"<tt>linkonce</tt>" linkage is similar to <tt>internal</tt> linkage, with
434 the twist that linking together two modules defining the same
435 <tt>linkonce</tt> globals will cause one of the globals to be discarded. This
436 is typically used to implement inline functions. Unreferenced
437 <tt>linkonce</tt> globals are allowed to be discarded.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]438 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]439
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]440 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]441
442 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
443 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]444 used to implement constructs in C such as "<tt>i32 X;</tt>" at global scope.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]445 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]446
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]447 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]448
449 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
450 pointer to array type. When two global variables with appending linkage are
451 linked together, the two global arrays are appended together. This is the
452 LLVM, typesafe, equivalent of having the system linker append together
453 "sections" with identical names when .o files are linked.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]454 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]455
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]456 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]457
458 <dd>If none of the above identifiers are used, the global is externally
459 visible, meaning that it participates in linkage and can be used to resolve
460 external symbol references.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]461 </dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]462
463 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
464
465 <dd>"<tt>extern_weak</tt>" TBD
466 </dd>
467
468 <p>
469 The next two types of linkage are targeted for Microsoft Windows platform
470 only. They are designed to support importing (exporting) symbols from (to)
471 DLLs.
472 </p>
473
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
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]493<p><a name="linkage_external">For example, since the "<tt>.LC0</tt>"
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>,
501or <tt>extern_weak</tt>.</a></p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]502
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]503</div>
504
505<!-- ======================================================================= -->
506<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]507 <a name="callingconv">Calling Conventions</a>
508</div>
509
510<div class="doc_text">
511
512<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
513and <a href="#i_invoke">invokes</a> can all have an optional calling convention
514specified for the call. The calling convention of any pair of dynamic
515caller/callee must match, or the behavior of the program is undefined. The
516following calling conventions are supported by LLVM, and more may be added in
517the future:</p>
518
519<dl>
520 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
521
522 <dd>This calling convention (the default if no other calling convention is
523 specified) matches the target C calling conventions. This calling convention
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]524 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencer72ba4992006-12-31 21:30:18 +0000[diff] [blame]525 prototype and implemented declaration of the function (as does normal C).
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]526 </dd>
527
Chris Lattner95ff1952006-05-19 21:15:36 +0000[diff] [blame]528 <dt><b>"<tt>csretcc</tt>" - The C struct return calling convention</b>:</dt>
529
530 <dd>This calling convention matches the target C calling conventions, except
531 that functions with this convention are required to take a pointer as their
532 first argument, and the return type of the function must be void. This is
533 used for C functions that return aggregates by-value. In this case, the
534 function has been transformed to take a pointer to the struct as the first
535 argument to the function. For targets where the ABI specifies specific
536 behavior for structure-return calls, the calling convention can be used to
537 distinguish between struct return functions and other functions that take a
538 pointer to a struct as the first argument.
539 </dd>
540
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]541 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
542
543 <dd>This calling convention attempts to make calls as fast as possible
544 (e.g. by passing things in registers). This calling convention allows the
545 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattnerc792eb32005-05-06 23:08:23 +0000[diff] [blame]546 without having to conform to an externally specified ABI. Implementations of
547 this convention should allow arbitrary tail call optimization to be supported.
548 This calling convention does not support varargs and requires the prototype of
549 all callees to exactly match the prototype of the function definition.
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]550 </dd>
551
552 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
553
554 <dd>This calling convention attempts to make code in the caller as efficient
555 as possible under the assumption that the call is not commonly executed. As
556 such, these calls often preserve all registers so that the call does not break
557 any live ranges in the caller side. This calling convention does not support
558 varargs and requires the prototype of all callees to exactly match the
559 prototype of the function definition.
560 </dd>
561
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]562 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]563
564 <dd>Any calling convention may be specified by number, allowing
565 target-specific calling conventions to be used. Target specific calling
566 conventions start at 64.
567 </dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]568</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]569
570<p>More calling conventions can be added/defined on an as-needed basis, to
571support pascal conventions or any other well-known target-independent
572convention.</p>
573
574</div>
575
576<!-- ======================================================================= -->
577<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]578 <a name="globalvars">Global Variables</a>
579</div>
580
581<div class="doc_text">
582
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]583<p>Global variables define regions of memory allocated at compilation time
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]584instead of run-time. Global variables may optionally be initialized, may have
585an explicit section to be placed in, and may
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]586have an optional explicit alignment specified. A
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]587variable may be defined as a global "constant," which indicates that the
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]588contents of the variable will <b>never</b> be modified (enabling better
589optimization, allowing the global data to be placed in the read-only section of
590an executable, etc). Note that variables that need runtime initialization
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]591cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]592
593<p>
594LLVM explicitly allows <em>declarations</em> of global variables to be marked
595constant, even if the final definition of the global is not. This capability
596can be used to enable slightly better optimization of the program, but requires
597the language definition to guarantee that optimizations based on the
598'constantness' are valid for the translation units that do not include the
599definition.
600</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]601
602<p>As SSA values, global variables define pointer values that are in
603scope (i.e. they dominate) all basic blocks in the program. Global
604variables always define a pointer to their "content" type because they
605describe a region of memory, and all memory objects in LLVM are
606accessed through pointers.</p>
607
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]608<p>LLVM allows an explicit section to be specified for globals. If the target
609supports it, it will emit globals to the section specified.</p>
610
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]611<p>An explicit alignment may be specified for a global. If not present, or if
612the alignment is set to zero, the alignment of the global is set by the target
613to whatever it feels convenient. If an explicit alignment is specified, the
614global is forced to have at least that much alignment. All alignments must be
615a power of 2.</p>
616
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]617</div>
618
619
620<!-- ======================================================================= -->
621<div class="doc_subsection">
622 <a name="functionstructure">Functions</a>
623</div>
624
625<div class="doc_text">
626
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]627<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
628an optional <a href="#linkage">linkage type</a>, an optional
629<a href="#callingconv">calling convention</a>, a return type, an optional
630<a href="#paramattrs">parameter attribute</a> for the return type, a function
631name, a (possibly empty) argument list (each with optional
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]632<a href="#paramattrs">parameter attributes</a>), an optional section, an
633optional alignment, an opening curly brace, a list of basic blocks, and a
634closing curly brace. LLVM function declarations
635consist of the "<tt>declare</tt>" keyword, an optional <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]636 href="#callingconv">calling convention</a>, a return type, an optional
637<a href="#paramattrs">parameter attribute</a> for the return type, a function
638name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]639
640<p>A function definition contains a list of basic blocks, forming the CFG for
641the function. Each basic block may optionally start with a label (giving the
642basic block a symbol table entry), contains a list of instructions, and ends
643with a <a href="#terminators">terminator</a> instruction (such as a branch or
644function return).</p>
645
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]646<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]647executed on entrance to the function, and it is not allowed to have predecessor
648basic blocks (i.e. there can not be any branches to the entry block of a
649function). Because the block can have no predecessors, it also cannot have any
650<a href="#i_phi">PHI nodes</a>.</p>
651
652<p>LLVM functions are identified by their name and type signature. Hence, two
653functions with the same name but different parameter lists or return values are
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]654considered different functions, and LLVM will resolve references to each
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]655appropriately.</p>
656
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]657<p>LLVM allows an explicit section to be specified for functions. If the target
658supports it, it will emit functions to the section specified.</p>
659
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]660<p>An explicit alignment may be specified for a function. If not present, or if
661the alignment is set to zero, the alignment of the function is set by the target
662to whatever it feels convenient. If an explicit alignment is specified, the
663function is forced to have at least that much alignment. All alignments must be
664a power of 2.</p>
665
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]666</div>
667
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]668<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]669<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
670<div class="doc_text">
671 <p>The return type and each parameter of a function type may have a set of
672 <i>parameter attributes</i> associated with them. Parameter attributes are
673 used to communicate additional information about the result or parameters of
674 a function. Parameter attributes are considered to be part of the function
675 type so two functions types that differ only by the parameter attributes
676 are different function types.</p>
677
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]678 <p>Parameter attributes consist of an at sign (@) followed by either a single
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]679 keyword or a comma separate list of keywords enclosed in parentheses. For
680 example:<pre>
681 %someFunc = i16 @zext (i8 @(sext) %someParam)
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]682 %someFunc = i16 @zext (i8 @zext %someParam)</pre>
683 Note that the two function types above are unique because the parameter
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]684 has a different attribute (@sext in the first one, @zext in the second).</p>
685
686 <p>Currently, only the following parameter attributes are defined:
687 <dl>
688 <dt><tt>@zext</tt></dt>
689 <dd>This indicates that the parameter should be zero extended just before
690 a call to this function.</dd>
691 <dt><tt>@sext</tt></dt>
692 <dd>This indicates that the parameter should be sign extended just before
693 a call to this function.</dd>
694 </dl></p>
695
696 <p>The current motivation for parameter attributes is to enable the sign and
697 zero extend information necessary for the C calling convention to be passed
698 from the front end to LLVM. The <tt>@zext</tt> and <tt>@sext</tt> attributes
699 are used by the code generator to perform the required extension. However,
700 parameter attributes are an orthogonal feature to calling conventions and
701 may be used for other purposes in the future.</p>
702</div>
703
704<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]705<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]706 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]707</div>
708
709<div class="doc_text">
710<p>
711Modules may contain "module-level inline asm" blocks, which corresponds to the
712GCC "file scope inline asm" blocks. These blocks are internally concatenated by
713LLVM and treated as a single unit, but may be separated in the .ll file if
714desired. The syntax is very simple:
715</p>
716
717<div class="doc_code"><pre>
Chris Lattnera1280ad2006-01-24 00:37:20 +0000[diff] [blame]718 module asm "inline asm code goes here"
719 module asm "more can go here"
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]720</pre></div>
721
722<p>The strings can contain any character by escaping non-printable characters.
723 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
724 for the number.
725</p>
726
727<p>
728 The inline asm code is simply printed to the machine code .s file when
729 assembly code is generated.
730</p>
731</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]732
733
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]734<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]735<div class="doc_section"> <a name="typesystem">Type System</a> </div>
736<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]737
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]738<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]739
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]740<p>The LLVM type system is one of the most important features of the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]741intermediate representation. Being typed enables a number of
742optimizations to be performed on the IR directly, without having to do
743extra analyses on the side before the transformation. A strong type
744system makes it easier to read the generated code and enables novel
745analyses and transformations that are not feasible to perform on normal
746three address code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]747
748</div>
749
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]750<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]751<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]752<div class="doc_text">
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]753<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]754system. The current set of primitive types is as follows:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]755
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]756<table class="layout">
757 <tr class="layout">
758 <td class="left">
759 <table>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]760 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]761 <tr><th>Type</th><th>Description</th></tr>
762 <tr><td><tt>void</tt></td><td>No value</td></tr>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]763 <tr><td><tt>i8</tt></td><td>Signless 8-bit value</td></tr>
764 <tr><td><tt>i32</tt></td><td>Signless 32-bit value</td></tr>
Misha Brukman36c6bc12005-04-22 18:02:52 +0000[diff] [blame]765 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]766 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]767 </tbody>
768 </table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]769 </td>
770 <td class="right">
771 <table>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]772 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]773 <tr><th>Type</th><th>Description</th></tr>
774 <tr><td><tt>bool</tt></td><td>True or False value</td></tr>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]775 <tr><td><tt>i16</tt></td><td>Signless 16-bit value</td></tr>
776 <tr><td><tt>i64</tt></td><td>Signless 64-bit value</td></tr>
777 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]778 </tbody>
779 </table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]780 </td>
781 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]782</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]783</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]784
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]785<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]786<div class="doc_subsubsection"> <a name="t_classifications">Type
787Classifications</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]788<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]789<p>These different primitive types fall into a few useful
790classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]791
792<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]793 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]794 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]795 <tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]796 <td><a name="t_integer">integer</a></td>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]797 <td><tt>i8, i16, i32, i64</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]798 </tr>
799 <tr>
800 <td><a name="t_integral">integral</a></td>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]801 <td><tt>bool, i8, i16, i32, i64</tt>
Misha Brukman20f9a622004-08-12 20:16:08 +0000[diff] [blame]802 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]803 </tr>
804 <tr>
805 <td><a name="t_floating">floating point</a></td>
806 <td><tt>float, double</tt></td>
807 </tr>
808 <tr>
809 <td><a name="t_firstclass">first class</a></td>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]810 <td><tt>bool, i8, i16, i32, i64, float, double, <br/>
811 <a href="#t_pointer">pointer</a>,<a href="#t_packed">packed</a></tt>
812 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]813 </tr>
814 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]815</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]816
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]817<p>The <a href="#t_firstclass">first class</a> types are perhaps the
818most important. Values of these types are the only ones which can be
819produced by instructions, passed as arguments, or used as operands to
820instructions. This means that all structures and arrays must be
821manipulated either by pointer or by component.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]822</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]823
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]824<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]825<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]826
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]827<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]828
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]829<p>The real power in LLVM comes from the derived types in the system.
830This is what allows a programmer to represent arrays, functions,
831pointers, and other useful types. Note that these derived types may be
832recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]833
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]834</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]835
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]836<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]837<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]838
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]839<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]840
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]841<h5>Overview:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]842
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]843<p>The array type is a very simple derived type that arranges elements
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]844sequentially in memory. The array type requires a size (number of
845elements) and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]846
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]847<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]848
849<pre>
850 [&lt;# elements&gt; x &lt;elementtype&gt;]
851</pre>
852
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]853<p>The number of elements is a constant integer value; elementtype may
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]854be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]855
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]856<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]857<table class="layout">
858 <tr class="layout">
859 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]860 <tt>[40 x i32 ]</tt><br/>
861 <tt>[41 x i32 ]</tt><br/>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]862 <tt>[40 x i8]</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]863 </td>
864 <td class="left">
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]865 Array of 40 32-bit integer values.<br/>
866 Array of 41 32-bit integer values.<br/>
867 Array of 40 8-bit integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]868 </td>
869 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]870</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]871<p>Here are some examples of multidimensional arrays:</p>
872<table class="layout">
873 <tr class="layout">
874 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]875 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]876 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]877 <tt>[2 x [3 x [4 x i16]]]</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]878 </td>
879 <td class="left">
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]880 3x4 array of 32-bit integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]881 12x10 array of single precision floating point values.<br/>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]882 2x3x4 array of 16-bit integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]883 </td>
884 </tr>
885</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]886
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]887<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
888length array. Normally, accesses past the end of an array are undefined in
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]889LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
890As a special case, however, zero length arrays are recognized to be variable
891length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]892type "{ i32, [0 x float]}", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]893
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]894</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]895
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]896<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]897<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]898<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]899<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]900<p>The function type can be thought of as a function signature. It
901consists of a return type and a list of formal parameter types.
John Criswella0d50d22003-11-25 21:45:46 +0000[diff] [blame]902Function types are usually used to build virtual function tables
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]903(which are structures of pointers to functions), for indirect function
904calls, and when defining a function.</p>
John Criswella0d50d22003-11-25 21:45:46 +0000[diff] [blame]905<p>
906The return type of a function type cannot be an aggregate type.
907</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]908<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]909<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]910<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]911specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]912which indicates that the function takes a variable number of arguments.
913Variable argument functions can access their arguments with the <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]914 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]915<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]916<table class="layout">
917 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]918 <td class="left"><tt>i32 (i32)</tt></td>
919 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]920 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]921 </tr><tr class="layout">
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]922 <td class="left"><tt>float&nbsp;(i16&nbsp;@sext,&nbsp;i32&nbsp;*)&nbsp;*
923 </tt></td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]924 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
925 an <tt>i16</tt> that should be sign extended and a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]926 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]927 <tt>float</tt>.
928 </td>
929 </tr><tr class="layout">
930 <td class="left"><tt>i32 (i8*, ...)</tt></td>
931 <td class="left">A vararg function that takes at least one
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]932 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]933 which returns an integer. This is the signature for <tt>printf</tt> in
934 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]935 </td>
936 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]937</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]938
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]939</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]940<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]941<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]942<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]943<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]944<p>The structure type is used to represent a collection of data members
945together in memory. The packing of the field types is defined to match
946the ABI of the underlying processor. The elements of a structure may
947be any type that has a size.</p>
948<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
949and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
950field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
951instruction.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]952<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]953<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]954<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]955<table class="layout">
956 <tr class="layout">
957 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]958 <tt>{ i32, i32, i32 }</tt><br/>
959 <tt>{ float, i32 (i32) * }</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]960 </td>
961 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]962 a triple of three <tt>i32</tt> values<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]963 A pair, where the first element is a <tt>float</tt> and the second element
964 is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]965 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]966 </td>
967 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]968</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]969</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]970
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]971<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]972<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
973</div>
974<div class="doc_text">
975<h5>Overview:</h5>
976<p>The packed structure type is used to represent a collection of data members
977together in memory. There is no padding between fields. Further, the alignment
978of a packed structure is 1 byte. The elements of a packed structure may
979be any type that has a size.</p>
980<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
981and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
982field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
983instruction.</p>
984<h5>Syntax:</h5>
985<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
986<h5>Examples:</h5>
987<table class="layout">
988 <tr class="layout">
989 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]990 <tt> &lt; { i32, i32, i32 } &gt; </tt><br/>
991 <tt> &lt; { float, i32 (i32) * } &gt; </tt><br/>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]992 </td>
993 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]994 a triple of three <tt>i32</tt> values<br/>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]995 A pair, where the first element is a <tt>float</tt> and the second element
996 is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]997 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]998 </td>
999 </tr>
1000</table>
1001</div>
1002
1003<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1004<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1005<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1006<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1007<p>As in many languages, the pointer type represents a pointer or
1008reference to another object, which must live in memory.</p>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1009<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1010<pre> &lt;type&gt; *<br></pre>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1011<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1012<table class="layout">
1013 <tr class="layout">
1014 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1015 <tt>[4x i32]*</tt><br/>
1016 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1017 </td>
1018 <td class="left">
1019 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]1020 four <tt>i32</tt> values<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1021 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1022 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1023 <tt>i32</tt>.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1024 </td>
1025 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1026</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1027</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1028
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1029<!-- _______________________________________________________________________ -->
1030<div class="doc_subsubsection"> <a name="t_packed">Packed Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1031<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1032
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1033<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1034
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1035<p>A packed type is a simple derived type that represents a vector
1036of elements. Packed types are used when multiple primitive data
1037are operated in parallel using a single instruction (SIMD).
1038A packed type requires a size (number of
Chris Lattner330ce692005-11-10 01:44:22 +0000[diff] [blame]1039elements) and an underlying primitive data type. Vectors must have a power
1040of two length (1, 2, 4, 8, 16 ...). Packed types are
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1041considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1042
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1043<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1044
1045<pre>
1046 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1047</pre>
1048
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1049<p>The number of elements is a constant integer value; elementtype may
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1050be any integral or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1051
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1052<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1053
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1054<table class="layout">
1055 <tr class="layout">
1056 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1057 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1058 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1059 <tt>&lt;2 x i64&gt;</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1060 </td>
1061 <td class="left">
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1062 Packed vector of 4 32-bit integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1063 Packed vector of 8 floating-point values.<br/>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1064 Packed vector of 2 64-bit integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1065 </td>
1066 </tr>
1067</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1068</div>
1069
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1070<!-- _______________________________________________________________________ -->
1071<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1072<div class="doc_text">
1073
1074<h5>Overview:</h5>
1075
1076<p>Opaque types are used to represent unknown types in the system. This
1077corresponds (for example) to the C notion of a foward declared structure type.
1078In LLVM, opaque types can eventually be resolved to any type (not just a
1079structure type).</p>
1080
1081<h5>Syntax:</h5>
1082
1083<pre>
1084 opaque
1085</pre>
1086
1087<h5>Examples:</h5>
1088
1089<table class="layout">
1090 <tr class="layout">
1091 <td class="left">
1092 <tt>opaque</tt>
1093 </td>
1094 <td class="left">
1095 An opaque type.<br/>
1096 </td>
1097 </tr>
1098</table>
1099</div>
1100
1101
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1102<!-- *********************************************************************** -->
1103<div class="doc_section"> <a name="constants">Constants</a> </div>
1104<!-- *********************************************************************** -->
1105
1106<div class="doc_text">
1107
1108<p>LLVM has several different basic types of constants. This section describes
1109them all and their syntax.</p>
1110
1111</div>
1112
1113<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1114<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1115
1116<div class="doc_text">
1117
1118<dl>
1119 <dt><b>Boolean constants</b></dt>
1120
1121 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1122 constants of the <tt><a href="#t_primitive">bool</a></tt> type.
1123 </dd>
1124
1125 <dt><b>Integer constants</b></dt>
1126
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1127 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1128 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1129 integer types.
1130 </dd>
1131
1132 <dt><b>Floating point constants</b></dt>
1133
1134 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1135 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1136 notation (see below). Floating point constants must have a <a
1137 href="#t_floating">floating point</a> type. </dd>
1138
1139 <dt><b>Null pointer constants</b></dt>
1140
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1141 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1142 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1143
1144</dl>
1145
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1146<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1147of floating point constants. For example, the form '<tt>double
11480x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
11494.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1150(and the only time that they are generated by the disassembler) is when a
1151floating point constant must be emitted but it cannot be represented as a
1152decimal floating point number. For example, NaN's, infinities, and other
1153special values are represented in their IEEE hexadecimal format so that
1154assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1155
1156</div>
1157
1158<!-- ======================================================================= -->
1159<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1160</div>
1161
1162<div class="doc_text">
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]1163<p>Aggregate constants arise from aggregation of simple constants
1164and smaller aggregate constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1165
1166<dl>
1167 <dt><b>Structure constants</b></dt>
1168
1169 <dd>Structure constants are represented with notation similar to structure
1170 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1171 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
1172 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]1173 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1174 types of elements must match those specified by the type.
1175 </dd>
1176
1177 <dt><b>Array constants</b></dt>
1178
1179 <dd>Array constants are represented with notation similar to array type
1180 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1181 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1182 constants must have <a href="#t_array">array type</a>, and the number and
1183 types of elements must match those specified by the type.
1184 </dd>
1185
1186 <dt><b>Packed constants</b></dt>
1187
1188 <dd>Packed constants are represented with notation similar to packed type
1189 definitions (a comma separated list of elements, surrounded by
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1190 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1191 i32 11, i32 74, i32 100 &gt;</tt>". Packed constants must have <a
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1192 href="#t_packed">packed type</a>, and the number and types of elements must
1193 match those specified by the type.
1194 </dd>
1195
1196 <dt><b>Zero initialization</b></dt>
1197
1198 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1199 value to zero of <em>any</em> type, including scalar and aggregate types.
1200 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]1201 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1202 initializers.
1203 </dd>
1204</dl>
1205
1206</div>
1207
1208<!-- ======================================================================= -->
1209<div class="doc_subsection">
1210 <a name="globalconstants">Global Variable and Function Addresses</a>
1211</div>
1212
1213<div class="doc_text">
1214
1215<p>The addresses of <a href="#globalvars">global variables</a> and <a
1216href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1217constants. These constants are explicitly referenced when the <a
1218href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1219href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1220file:</p>
1221
1222<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1223 %X = global i32 17
1224 %Y = global i32 42
1225 %Z = global [2 x i32*] [ i32* %X, i32* %Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1226</pre>
1227
1228</div>
1229
1230<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1231<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1232<div class="doc_text">
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1233 <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]1234 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1235 a constant is permitted.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1236
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1237 <p>Undefined values indicate to the compiler that the program is well defined
1238 no matter what value is used, giving the compiler more freedom to optimize.
1239 </p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1240</div>
1241
1242<!-- ======================================================================= -->
1243<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1244</div>
1245
1246<div class="doc_text">
1247
1248<p>Constant expressions are used to allow expressions involving other constants
1249to be used as constants. Constant expressions may be of any <a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1250href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1251that does not have side effects (e.g. load and call are not supported). The
1252following is the syntax for constant expressions:</p>
1253
1254<dl>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1255 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1256 <dd>Truncate a constant to another type. The bit size of CST must be larger
1257 than the bit size of TYPE. Both types must be integral.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1258
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1259 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1260 <dd>Zero extend a constant to another type. The bit size of CST must be
1261 smaller or equal to the bit size of TYPE. Both types must be integral.</dd>
1262
1263 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1264 <dd>Sign extend a constant to another type. The bit size of CST must be
1265 smaller or equal to the bit size of TYPE. Both types must be integral.</dd>
1266
1267 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1268 <dd>Truncate a floating point constant to another floating point type. The
1269 size of CST must be larger than the size of TYPE. Both types must be
1270 floating point.</dd>
1271
1272 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1273 <dd>Floating point extend a constant to another type. The size of CST must be
1274 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1275
1276 <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt>
1277 <dd>Convert a floating point constant to the corresponding unsigned integer
1278 constant. TYPE must be an integer type. CST must be floating point. If the
1279 value won't fit in the integer type, the results are undefined.</dd>
1280
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1281 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1282 <dd>Convert a floating point constant to the corresponding signed integer
1283 constant. TYPE must be an integer type. CST must be floating point. If the
1284 value won't fit in the integer type, the results are undefined.</dd>
1285
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1286 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1287 <dd>Convert an unsigned integer constant to the corresponding floating point
1288 constant. TYPE must be floating point. CST must be of integer type. If the
1289 value won't fit in the floating point type, the results are undefined.</dd>
1290
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1291 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1292 <dd>Convert a signed integer constant to the corresponding floating point
1293 constant. TYPE must be floating point. CST must be of integer type. If the
1294 value won't fit in the floating point type, the results are undefined.</dd>
1295
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1296 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1297 <dd>Convert a pointer typed constant to the corresponding integer constant
1298 TYPE must be an integer type. CST must be of pointer type. The CST value is
1299 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1300
1301 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1302 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1303 pointer type. CST must be of integer type. The CST value is zero extended,
1304 truncated, or unchanged to make it fit in a pointer size. This one is
1305 <i>really</i> dangerous!</dd>
1306
1307 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1308 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1309 identical (same number of bits). The conversion is done as if the CST value
1310 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]1311 with this operator, just the type. This can be used for conversion of
1312 packed types to any other type, as long as they have the same bit width. For
1313 pointers it is only valid to cast to another pointer type.
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1314 </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1315
1316 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1317
1318 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1319 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1320 instruction, the index list may have zero or more indexes, which are required
1321 to make sense for the type of "CSTPTR".</dd>
1322
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1323 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1324
1325 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1326 constants.</dd>
1327
1328 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1329 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1330
1331 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1332 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1333
1334 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1335
1336 <dd>Perform the <a href="#i_extractelement">extractelement
1337 operation</a> on constants.
1338
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1339 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1340
1341 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1342 operation</a> on constants.</dd>
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1343
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1344
1345 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1346
1347 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1348 operation</a> on constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1349
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1350 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1351
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1352 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1353 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1354 binary</a> operations. The constraints on operands are the same as those for
1355 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1356 values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1357</dl>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1358</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]1359
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1360<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1361<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1362<!-- *********************************************************************** -->
1363
1364<!-- ======================================================================= -->
1365<div class="doc_subsection">
1366<a name="inlineasm">Inline Assembler Expressions</a>
1367</div>
1368
1369<div class="doc_text">
1370
1371<p>
1372LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1373Module-Level Inline Assembly</a>) through the use of a special value. This
1374value represents the inline assembler as a string (containing the instructions
1375to emit), a list of operand constraints (stored as a string), and a flag that
1376indicates whether or not the inline asm expression has side effects. An example
1377inline assembler expression is:
1378</p>
1379
1380<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1381 i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1382</pre>
1383
1384<p>
1385Inline assembler expressions may <b>only</b> be used as the callee operand of
1386a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1387</p>
1388
1389<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1390 %X = call i32 asm "<a href="#i_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1391</pre>
1392
1393<p>
1394Inline asms with side effects not visible in the constraint list must be marked
1395as having side effects. This is done through the use of the
1396'<tt>sideeffect</tt>' keyword, like so:
1397</p>
1398
1399<pre>
1400 call void asm sideeffect "eieio", ""()
1401</pre>
1402
1403<p>TODO: The format of the asm and constraints string still need to be
1404documented here. Constraints on what can be done (e.g. duplication, moving, etc
1405need to be documented).
1406</p>
1407
1408</div>
1409
1410<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1411<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1412<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1413
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1414<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1415
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1416<p>The LLVM instruction set consists of several different
1417classifications of instructions: <a href="#terminators">terminator
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1418instructions</a>, <a href="#binaryops">binary instructions</a>,
1419<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1420 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1421instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1422
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1423</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1424
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1425<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1426<div class="doc_subsection"> <a name="terminators">Terminator
1427Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1428
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1429<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1430
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1431<p>As mentioned <a href="#functionstructure">previously</a>, every
1432basic block in a program ends with a "Terminator" instruction, which
1433indicates which block should be executed after the current block is
1434finished. These terminator instructions typically yield a '<tt>void</tt>'
1435value: they produce control flow, not values (the one exception being
1436the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1437<p>There are six different terminator instructions: the '<a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1438 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1439instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1440the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1441 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1442 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1443
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1444</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1445
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1446<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1447<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1448Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1449<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1450<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1451<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]1452 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1453</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1454<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1455<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1456value) from a function back to the caller.</p>
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]1457<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1458returns a value and then causes control flow, and one that just causes
1459control flow to occur.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1460<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1461<p>The '<tt>ret</tt>' instruction may return any '<a
1462 href="#t_firstclass">first class</a>' type. Notice that a function is
1463not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1464instruction inside of the function that returns a value that does not
1465match the return type of the function.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1466<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1467<p>When the '<tt>ret</tt>' instruction is executed, control flow
1468returns back to the calling function's context. If the caller is a "<a
John Criswell40db33f2004-06-25 15:16:57 +0000[diff] [blame]1469 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1470the instruction after the call. If the caller was an "<a
1471 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1472at the beginning of the "normal" destination block. If the instruction
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1473returns a value, that value shall set the call or invoke instruction's
1474return value.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1475<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1476<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1477 ret void <i>; Return from a void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1478</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1479</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1480<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1481<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1482<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1483<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1484<pre> br bool &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1485</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1486<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1487<p>The '<tt>br</tt>' instruction is used to cause control flow to
1488transfer to a different basic block in the current function. There are
1489two forms of this instruction, corresponding to a conditional branch
1490and an unconditional branch.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1491<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1492<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
1493single '<tt>bool</tt>' value and two '<tt>label</tt>' values. The
1494unconditional form of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>'
1495value as a target.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1496<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1497<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>bool</tt>'
1498argument is evaluated. If the value is <tt>true</tt>, control flows
1499to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1500control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1501<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1502<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq, i32 %a, %b<br> br bool %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
1503 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]1504</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1505<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1506<div class="doc_subsubsection">
1507 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1508</div>
1509
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1510<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1511<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1512
1513<pre>
1514 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1515</pre>
1516
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1517<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1518
1519<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1520several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1521instruction, allowing a branch to occur to one of many possible
1522destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1523
1524
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1525<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1526
1527<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1528comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1529an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1530table is not allowed to contain duplicate constant entries.</p>
1531
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1532<h5>Semantics:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1533
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1534<p>The <tt>switch</tt> instruction specifies a table of values and
1535destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1536table is searched for the given value. If the value is found, control flow is
1537transfered to the corresponding destination; otherwise, control flow is
1538transfered to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1539
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1540<h5>Implementation:</h5>
1541
1542<p>Depending on properties of the target machine and the particular
1543<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1544ways. For example, it could be generated as a series of chained conditional
1545branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1546
1547<h5>Example:</h5>
1548
1549<pre>
1550 <i>; Emulate a conditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1551 %Val = <a href="#i_zext">zext</a> bool %value to i32
1552 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1553
1554 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1555 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1556
1557 <i>; Implement a jump table:</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1558 switch i32 %val, label %otherwise [ i32 0, label %onzero
1559 i32 1, label %onone
1560 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1561</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1562</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1563
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1564<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1565<div class="doc_subsubsection">
1566 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1567</div>
1568
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1569<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1570
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1571<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1572
1573<pre>
1574 &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]1575 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1576</pre>
1577
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]1578<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1579
1580<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1581function, with the possibility of control flow transfer to either the
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1582'<tt>normal</tt>' label or the
1583'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1584"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1585"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1586href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1587continued at the dynamically nearest "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1588
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1589<h5>Arguments:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1590
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1591<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1592
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1593<ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1594 <li>
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1595 The optional "cconv" marker indicates which <a href="callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1596 convention</a> the call should use. If none is specified, the call defaults
1597 to using C calling conventions.
1598 </li>
1599 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1600 function value being invoked. In most cases, this is a direct function
1601 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1602 an arbitrary pointer to function value.
1603 </li>
1604
1605 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1606 function to be invoked. </li>
1607
1608 <li>'<tt>function args</tt>': argument list whose types match the function
1609 signature argument types. If the function signature indicates the function
1610 accepts a variable number of arguments, the extra arguments can be
1611 specified. </li>
1612
1613 <li>'<tt>normal label</tt>': the label reached when the called function
1614 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1615
1616 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1617 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1618
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1619</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1620
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1621<h5>Semantics:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1622
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1623<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1624href="#i_call">call</a></tt>' instruction in most regards. The primary
1625difference is that it establishes an association with a label, which is used by
1626the runtime library to unwind the stack.</p>
1627
1628<p>This instruction is used in languages with destructors to ensure that proper
1629cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1630exception. Additionally, this is important for implementation of
1631'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1632
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1633<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1634<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1635 %retval = invoke i32 %Test(i32 15) to label %Continue
1636 unwind label %TestCleanup <i>; {i32}:retval set</i>
1637 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1638 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1639</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1640</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1641
1642
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1643<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1644
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1645<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1646Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1647
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1648<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1649
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1650<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1651<pre>
1652 unwind
1653</pre>
1654
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1655<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1656
1657<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1658at the first callee in the dynamic call stack which used an <a
1659href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1660primarily used to implement exception handling.</p>
1661
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1662<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1663
1664<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1665immediately halt. The dynamic call stack is then searched for the first <a
1666href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1667execution continues at the "exceptional" destination block specified by the
1668<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1669dynamic call chain, undefined behavior results.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1670</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1671
1672<!-- _______________________________________________________________________ -->
1673
1674<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1675Instruction</a> </div>
1676
1677<div class="doc_text">
1678
1679<h5>Syntax:</h5>
1680<pre>
1681 unreachable
1682</pre>
1683
1684<h5>Overview:</h5>
1685
1686<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1687instruction is used to inform the optimizer that a particular portion of the
1688code is not reachable. This can be used to indicate that the code after a
1689no-return function cannot be reached, and other facts.</p>
1690
1691<h5>Semantics:</h5>
1692
1693<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1694</div>
1695
1696
1697
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1698<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1699<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1700<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1701<p>Binary operators are used to do most of the computation in a
1702program. They require two operands, execute an operation on them, and
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1703produce a single value. The operands might represent
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1704multiple data, as is the case with the <a href="#t_packed">packed</a> data type.
1705The result value of a binary operator is not
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1706necessarily the same type as its operands.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1707<p>There are several different binary operators:</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1708</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1709<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1710<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1711Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1712<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1713<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1714<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]1715</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1716<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1717<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1718<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1719<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1720 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
1721 This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1722Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1723<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1724<p>The value produced is the integer or floating point sum of the two
1725operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1726<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1727<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]1728</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1729</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1730<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1731<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1732Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1733<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1734<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1735<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]1736</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1737<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1738<p>The '<tt>sub</tt>' instruction returns the difference of its two
1739operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1740<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1741instruction present in most other intermediate representations.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1742<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1743<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1744 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1745values.
1746This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1747Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1748<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1749<p>The value produced is the integer or floating point difference of
1750the two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1751<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1752<pre> &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
1753 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1754</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1755</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1756<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1757<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1758Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1759<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1760<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1761<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]1762</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1763<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1764<p>The '<tt>mul</tt>' instruction returns the product of its two
1765operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1766<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1767<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1768 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1769values.
1770This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1771Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1772<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1773<p>The value produced is the integer or floating point product of the
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1774two operands.</p>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1775<p>Because the operands are the same width, the result of an integer
1776multiplication is the same whether the operands should be deemed unsigned or
1777signed.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1778<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1779<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]1780</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1781</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1782<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1783<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
1784</a></div>
1785<div class="doc_text">
1786<h5>Syntax:</h5>
1787<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1788</pre>
1789<h5>Overview:</h5>
1790<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
1791operands.</p>
1792<h5>Arguments:</h5>
1793<p>The two arguments to the '<tt>udiv</tt>' instruction must be
1794<a href="#t_integer">integer</a> values. Both arguments must have identical
1795types. This instruction can also take <a href="#t_packed">packed</a> versions
1796of the values in which case the elements must be integers.</p>
1797<h5>Semantics:</h5>
1798<p>The value produced is the unsigned integer quotient of the two operands. This
1799instruction always performs an unsigned division operation, regardless of
1800whether the arguments are unsigned or not.</p>
1801<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1802<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]1803</pre>
1804</div>
1805<!-- _______________________________________________________________________ -->
1806<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
1807</a> </div>
1808<div class="doc_text">
1809<h5>Syntax:</h5>
1810<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1811</pre>
1812<h5>Overview:</h5>
1813<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
1814operands.</p>
1815<h5>Arguments:</h5>
1816<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
1817<a href="#t_integer">integer</a> values. Both arguments must have identical
1818types. This instruction can also take <a href="#t_packed">packed</a> versions
1819of the values in which case the elements must be integers.</p>
1820<h5>Semantics:</h5>
1821<p>The value produced is the signed integer quotient of the two operands. This
1822instruction always performs a signed division operation, regardless of whether
1823the arguments are signed or not.</p>
1824<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1825<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]1826</pre>
1827</div>
1828<!-- _______________________________________________________________________ -->
1829<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1830Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1831<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1832<h5>Syntax:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1833<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]1834</pre>
1835<h5>Overview:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1836<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1837operands.</p>
1838<h5>Arguments:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1839<p>The two arguments to the '<tt>div</tt>' instruction must be
1840<a href="#t_floating">floating point</a> values. Both arguments must have
1841identical types. This instruction can also take <a href="#t_packed">packed</a>
1842versions of the values in which case the elements must be floating point.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1843<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1844<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1845<h5>Example:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1846<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]1847</pre>
1848</div>
1849<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]1850<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
1851</div>
1852<div class="doc_text">
1853<h5>Syntax:</h5>
1854<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1855</pre>
1856<h5>Overview:</h5>
1857<p>The '<tt>urem</tt>' instruction returns the remainder from the
1858unsigned division of its two arguments.</p>
1859<h5>Arguments:</h5>
1860<p>The two arguments to the '<tt>urem</tt>' instruction must be
1861<a href="#t_integer">integer</a> values. Both arguments must have identical
1862types.</p>
1863<h5>Semantics:</h5>
1864<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
1865This instruction always performs an unsigned division to get the remainder,
1866regardless of whether the arguments are unsigned or not.</p>
1867<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1868<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]1869</pre>
1870
1871</div>
1872<!-- _______________________________________________________________________ -->
1873<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1874Instruction</a> </div>
1875<div class="doc_text">
1876<h5>Syntax:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]1877<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]1878</pre>
1879<h5>Overview:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]1880<p>The '<tt>srem</tt>' instruction returns the remainder from the
1881signed division of its two operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1882<h5>Arguments:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]1883<p>The two arguments to the '<tt>srem</tt>' instruction must be
1884<a href="#t_integer">integer</a> values. Both arguments must have identical
1885types.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1886<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]1887<p>This instruction returns the <i>remainder</i> of a division (where the result
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1888has the same sign as the divisor), not the <i>modulus</i> (where the
1889result has the same sign as the dividend) of a value. For more
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1890information about the difference, see <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1891 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
1892Math Forum</a>.</p>
1893<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1894<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]1895</pre>
1896
1897</div>
1898<!-- _______________________________________________________________________ -->
1899<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
1900Instruction</a> </div>
1901<div class="doc_text">
1902<h5>Syntax:</h5>
1903<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1904</pre>
1905<h5>Overview:</h5>
1906<p>The '<tt>frem</tt>' instruction returns the remainder from the
1907division of its two operands.</p>
1908<h5>Arguments:</h5>
1909<p>The two arguments to the '<tt>frem</tt>' instruction must be
1910<a href="#t_floating">floating point</a> values. Both arguments must have
1911identical types.</p>
1912<h5>Semantics:</h5>
1913<p>This instruction returns the <i>remainder</i> of a division.</p>
1914<h5>Example:</h5>
1915<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]1916</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1917</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]1918
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1919<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1920<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
1921Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1922<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1923<p>Bitwise binary operators are used to do various forms of
1924bit-twiddling in a program. They are generally very efficient
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1925instructions and can commonly be strength reduced from other
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1926instructions. They require two operands, execute an operation on them,
1927and produce a single value. The resulting value of the bitwise binary
1928operators is always the same type as its first operand.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1929</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1930<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1931<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
1932Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1933<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1934<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1935<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]1936</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1937<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1938<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
1939its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1940<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1941<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1942 href="#t_integral">integral</a> values. Both arguments must have
1943identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1944<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1945<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1946<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1947<div style="align: center">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1948<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1949 <tbody>
1950 <tr>
1951 <td>In0</td>
1952 <td>In1</td>
1953 <td>Out</td>
1954 </tr>
1955 <tr>
1956 <td>0</td>
1957 <td>0</td>
1958 <td>0</td>
1959 </tr>
1960 <tr>
1961 <td>0</td>
1962 <td>1</td>
1963 <td>0</td>
1964 </tr>
1965 <tr>
1966 <td>1</td>
1967 <td>0</td>
1968 <td>0</td>
1969 </tr>
1970 <tr>
1971 <td>1</td>
1972 <td>1</td>
1973 <td>1</td>
1974 </tr>
1975 </tbody>
1976</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1977</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1978<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1979<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
1980 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
1981 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1982</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1983</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1984<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1985<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1986<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1987<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1988<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]1989</pre>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1990<h5>Overview:</h5>
1991<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
1992or of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1993<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1994<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1995 href="#t_integral">integral</a> values. Both arguments must have
1996identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1997<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1998<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1999<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2000<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2001<table border="1" cellspacing="0" cellpadding="4">
2002 <tbody>
2003 <tr>
2004 <td>In0</td>
2005 <td>In1</td>
2006 <td>Out</td>
2007 </tr>
2008 <tr>
2009 <td>0</td>
2010 <td>0</td>
2011 <td>0</td>
2012 </tr>
2013 <tr>
2014 <td>0</td>
2015 <td>1</td>
2016 <td>1</td>
2017 </tr>
2018 <tr>
2019 <td>1</td>
2020 <td>0</td>
2021 <td>1</td>
2022 </tr>
2023 <tr>
2024 <td>1</td>
2025 <td>1</td>
2026 <td>1</td>
2027 </tr>
2028 </tbody>
2029</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2030</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2031<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2032<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2033 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2034 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2035</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2036</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2037<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2038<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2039Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2040<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2041<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2042<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]2043</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2044<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2045<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2046or of its two operands. The <tt>xor</tt> is used to implement the
2047"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2048<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2049<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2050 href="#t_integral">integral</a> values. Both arguments must have
2051identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2052<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2053<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2054<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2055<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2056<table border="1" cellspacing="0" cellpadding="4">
2057 <tbody>
2058 <tr>
2059 <td>In0</td>
2060 <td>In1</td>
2061 <td>Out</td>
2062 </tr>
2063 <tr>
2064 <td>0</td>
2065 <td>0</td>
2066 <td>0</td>
2067 </tr>
2068 <tr>
2069 <td>0</td>
2070 <td>1</td>
2071 <td>1</td>
2072 </tr>
2073 <tr>
2074 <td>1</td>
2075 <td>0</td>
2076 <td>1</td>
2077 </tr>
2078 <tr>
2079 <td>1</td>
2080 <td>1</td>
2081 <td>0</td>
2082 </tr>
2083 </tbody>
2084</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2085</div>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2086<p> </p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2087<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2088<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2089 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2090 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2091 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2092</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2093</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2094<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2095<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2096Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2097<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2098<h5>Syntax:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2099<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, i8 &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2100</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2101<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2102<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2103the left a specified number of bits.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2104<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2105<p>The first argument to the '<tt>shl</tt>' instruction must be an <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2106 href="#t_integer">integer</a> type. The second argument must be an '<tt>i8</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2107type.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2108<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2109<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2110<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2111<pre> &lt;result&gt; = shl i32 4, i8 %var <i>; yields {i32}:result = 4 &lt;&lt; %var</i>
2112 &lt;result&gt; = shl i32 4, i8 2 <i>; yields {i32}:result = 16</i>
2113 &lt;result&gt; = shl i32 1, i8 10 <i>; yields {i32}:result = 1024</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2114</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2115</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2116<!-- _______________________________________________________________________ -->
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2117<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2118Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2119<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2120<h5>Syntax:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2121<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, i8 &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2122</pre>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2123
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2124<h5>Overview:</h5>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2125<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2126operand shifted to the right a specified number of bits.</p>
2127
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2128<h5>Arguments:</h5>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2129<p>The first argument to the '<tt>lshr</tt>' instruction must be an <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2130 href="#t_integer">integer</a> type. The second argument must be an '<tt>i8</tt>' type.</p>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2131
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2132<h5>Semantics:</h5>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]2133<p>This instruction always performs a logical shift right operation. The
2134<tt>var2</tt> most significant bits will be filled with zero bits after the
2135shift.</p>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2136
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2137<h5>Example:</h5>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2138<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2139 &lt;result&gt; = lshr i32 4, i8 1 <i>; yields {i32}:result = 2</i>
2140 &lt;result&gt; = lshr i32 4, i8 2 <i>; yields {i32}:result = 1</i>
2141 &lt;result&gt; = lshr i8 4, i8 3 <i>; yields {i8 }:result = 0</i>
2142 &lt;result&gt; = lshr i8 -2, i8 1 <i>; yields {i8 }:result = 0x7FFFFFFF </i>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2143</pre>
2144</div>
2145
2146<!-- ======================================================================= -->
2147<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2148Instruction</a> </div>
2149<div class="doc_text">
2150
2151<h5>Syntax:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2152<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, i8 &lt;var2&gt; <i>; yields {ty}:result</i>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2153</pre>
2154
2155<h5>Overview:</h5>
2156<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2157operand shifted to the right a specified number of bits.</p>
2158
2159<h5>Arguments:</h5>
2160<p>The first argument to the '<tt>ashr</tt>' instruction must be an
2161<a href="#t_integer">integer</a> type. The second argument must be an
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2162'<tt>i8</tt>' type.</p>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2163
2164<h5>Semantics:</h5>
2165<p>This instruction always performs an arithmetic shift right operation,
2166regardless of whether the arguments are signed or not. The <tt>var2</tt> most
2167significant bits will be filled with the sign bit of <tt>var1</tt>.</p>
2168
2169<h5>Example:</h5>
2170<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2171 &lt;result&gt; = ashr i32 4, i8 1 <i>; yields {i32}:result = 2</i>
2172 &lt;result&gt; = ashr i32 4, i8 2 <i>; yields {i32}:result = 1</i>
2173 &lt;result&gt; = ashr i8 4, i8 3 <i>; yields {i8}:result = 0</i>
2174 &lt;result&gt; = ashr i8 -2, i8 1 <i>; yields {i8 }:result = -1</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2175</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2176</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2177
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2178<!-- ======================================================================= -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2179<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2180 <a name="vectorops">Vector Operations</a>
2181</div>
2182
2183<div class="doc_text">
2184
2185<p>LLVM supports several instructions to represent vector operations in a
2186target-independent manner. This instructions cover the element-access and
2187vector-specific operations needed to process vectors effectively. While LLVM
2188does directly support these vector operations, many sophisticated algorithms
2189will want to use target-specific intrinsics to take full advantage of a specific
2190target.</p>
2191
2192</div>
2193
2194<!-- _______________________________________________________________________ -->
2195<div class="doc_subsubsection">
2196 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2197</div>
2198
2199<div class="doc_text">
2200
2201<h5>Syntax:</h5>
2202
2203<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2204 &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]2205</pre>
2206
2207<h5>Overview:</h5>
2208
2209<p>
2210The '<tt>extractelement</tt>' instruction extracts a single scalar
2211element from a packed vector at a specified index.
2212</p>
2213
2214
2215<h5>Arguments:</h5>
2216
2217<p>
2218The first operand of an '<tt>extractelement</tt>' instruction is a
2219value of <a href="#t_packed">packed</a> type. The second operand is
2220an index indicating the position from which to extract the element.
2221The index may be a variable.</p>
2222
2223<h5>Semantics:</h5>
2224
2225<p>
2226The result is a scalar of the same type as the element type of
2227<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2228<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2229results are undefined.
2230</p>
2231
2232<h5>Example:</h5>
2233
2234<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2235 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2236</pre>
2237</div>
2238
2239
2240<!-- _______________________________________________________________________ -->
2241<div class="doc_subsubsection">
2242 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2243</div>
2244
2245<div class="doc_text">
2246
2247<h5>Syntax:</h5>
2248
2249<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2250 &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]2251</pre>
2252
2253<h5>Overview:</h5>
2254
2255<p>
2256The '<tt>insertelement</tt>' instruction inserts a scalar
2257element into a packed vector at a specified index.
2258</p>
2259
2260
2261<h5>Arguments:</h5>
2262
2263<p>
2264The first operand of an '<tt>insertelement</tt>' instruction is a
2265value of <a href="#t_packed">packed</a> type. The second operand is a
2266scalar value whose type must equal the element type of the first
2267operand. The third operand is an index indicating the position at
2268which to insert the value. The index may be a variable.</p>
2269
2270<h5>Semantics:</h5>
2271
2272<p>
2273The result is a packed vector of the same type as <tt>val</tt>. Its
2274element values are those of <tt>val</tt> except at position
2275<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2276exceeds the length of <tt>val</tt>, the results are undefined.
2277</p>
2278
2279<h5>Example:</h5>
2280
2281<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2282 %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]2283</pre>
2284</div>
2285
2286<!-- _______________________________________________________________________ -->
2287<div class="doc_subsubsection">
2288 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2289</div>
2290
2291<div class="doc_text">
2292
2293<h5>Syntax:</h5>
2294
2295<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2296 &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]2297</pre>
2298
2299<h5>Overview:</h5>
2300
2301<p>
2302The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2303from two input vectors, returning a vector of the same type.
2304</p>
2305
2306<h5>Arguments:</h5>
2307
2308<p>
2309The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2310with types that match each other and types that match the result of the
2311instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2312of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2313</p>
2314
2315<p>
2316The shuffle mask operand is required to be a constant vector with either
2317constant integer or undef values.
2318</p>
2319
2320<h5>Semantics:</h5>
2321
2322<p>
2323The elements of the two input vectors are numbered from left to right across
2324both of the vectors. The shuffle mask operand specifies, for each element of
2325the result vector, which element of the two input registers the result element
2326gets. The element selector may be undef (meaning "don't care") and the second
2327operand may be undef if performing a shuffle from only one vector.
2328</p>
2329
2330<h5>Example:</h5>
2331
2332<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2333 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
2334 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
2335 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2336 &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]2337</pre>
2338</div>
2339
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]2340
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2341<!-- ======================================================================= -->
2342<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]2343 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2344</div>
2345
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2346<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2347
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2348<p>A key design point of an SSA-based representation is how it
2349represents memory. In LLVM, no memory locations are in SSA form, which
2350makes things very simple. This section describes how to read, write,
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2351allocate, and free memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2352
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2353</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2354
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2355<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2356<div class="doc_subsubsection">
2357 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2358</div>
2359
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2360<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2361
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2362<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2363
2364<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2365 &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]2366</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2367
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2368<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2369
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2370<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2371heap and returns a pointer to it.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2372
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2373<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2374
2375<p>The '<tt>malloc</tt>' instruction allocates
2376<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswella92e5862004-02-24 16:13:56 +0000[diff] [blame]2377bytes of memory from the operating system and returns a pointer of the
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2378appropriate type to the program. If "NumElements" is specified, it is the
2379number of elements allocated. If an alignment is specified, the value result
2380of the allocation is guaranteed to be aligned to at least that boundary. If
2381not specified, or if zero, the target can choose to align the allocation on any
2382convenient boundary.</p>
2383
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2384<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2385
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2386<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2387
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2388<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2389a pointer is returned.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2390
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2391<h5>Example:</h5>
2392
2393<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2394 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2395
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2396 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2397 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2398 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2399 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2400 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2401</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2402</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2403
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2404<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2405<div class="doc_subsubsection">
2406 <a name="i_free">'<tt>free</tt>' Instruction</a>
2407</div>
2408
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2409<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2410
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2411<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2412
2413<pre>
2414 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2415</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2416
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2417<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2418
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2419<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2420memory heap to be reallocated in the future.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2421
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2422<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2423
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2424<p>'<tt>value</tt>' shall be a pointer value that points to a value
2425that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2426instruction.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2427
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2428<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2429
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2430<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2431after this instruction executes.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2432
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2433<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2434
2435<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2436 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2437 free [4 x i8]* %array
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2438</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2439</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2440
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2441<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2442<div class="doc_subsubsection">
2443 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2444</div>
2445
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2446<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2447
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2448<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2449
2450<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2451 &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]2452</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2453
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2454<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2455
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2456<p>The '<tt>alloca</tt>' instruction allocates memory on the current
2457stack frame of the procedure that is live until the current function
2458returns to its caller.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2459
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2460<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2461
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2462<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2463bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2464appropriate type to the program. If "NumElements" is specified, it is the
2465number of elements allocated. If an alignment is specified, the value result
2466of the allocation is guaranteed to be aligned to at least that boundary. If
2467not specified, or if zero, the target can choose to align the allocation on any
2468convenient boundary.</p>
2469
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2470<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2471
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2472<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2473
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2474<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2475memory is automatically released when the function returns. The '<tt>alloca</tt>'
2476instruction is commonly used to represent automatic variables that must
2477have an address available. When the function returns (either with the <tt><a
John Criswellc932bef2005-05-12 16:55:34 +0000[diff] [blame]2478 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]2479instructions), the memory is reclaimed.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2480
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2481<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2482
2483<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2484 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
2485 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2486 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
2487 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2488</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2489</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2490
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2491<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2492<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2493Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2494<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2495<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2496<pre> &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;<br> &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;<br></pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2497<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2498<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2499<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2500<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2501address from which to load. The pointer must point to a <a
Chris Lattner10ee9652004-06-03 22:57:15 +0000[diff] [blame]2502 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2503marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2504the number or order of execution of this <tt>load</tt> with other
2505volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2506instructions. </p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2507<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2508<p>The location of memory pointed to is loaded.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2509<h5>Examples:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2510<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2511 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2512 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2513 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2514</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2515</div>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2516<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2517<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2518Instruction</a> </div>
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]2519<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2520<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2521<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; <i>; yields {void}</i>
Chris Lattner12d456c2003-09-08 18:27:49 +0000[diff] [blame]2522 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2523</pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2524<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2525<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2526<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2527<p>There are two arguments to the '<tt>store</tt>' instruction: a value
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2528to store and an address in which to store it. The type of the '<tt>&lt;pointer&gt;</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2529operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2530operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2531optimizer is not allowed to modify the number or order of execution of
2532this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2533 href="#i_store">store</a></tt> instructions.</p>
2534<h5>Semantics:</h5>
2535<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2536at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2537<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2538<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2539 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2540 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2541 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2542</pre>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]2543</div>
2544
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2545<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2546<div class="doc_subsubsection">
2547 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2548</div>
2549
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2550<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2551<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2552<pre>
2553 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2554</pre>
2555
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2556<h5>Overview:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2557
2558<p>
2559The '<tt>getelementptr</tt>' instruction is used to get the address of a
2560subelement of an aggregate data structure.</p>
2561
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2562<h5>Arguments:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2563
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2564<p>This instruction takes a list of integer operands that indicate what
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2565elements of the aggregate object to index to. The actual types of the arguments
2566provided depend on the type of the first pointer argument. The
2567'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]2568levels 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]2569structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2570into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2571be sign extended to 64-bit values.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2572
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2573<p>For example, let's consider a C code fragment and how it gets
2574compiled to LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2575
2576<pre>
2577 struct RT {
2578 char A;
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2579 i32 B[10][20];
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2580 char C;
2581 };
2582 struct ST {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2583 i32 X;
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2584 double Y;
2585 struct RT Z;
2586 };
2587
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2588 define i32 *foo(struct ST *s) {
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2589 return &amp;s[1].Z.B[5][13];
2590 }
2591</pre>
2592
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2593<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2594
2595<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2596 %RT = type { i8 , [10 x [20 x i32]], i8 }
2597 %ST = type { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2598
Brian Gaeke317ef962004-07-02 21:08:14 +0000[diff] [blame]2599 implementation
2600
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2601 define i32* %foo(%ST* %s) {
Brian Gaeke317ef962004-07-02 21:08:14 +0000[diff] [blame]2602 entry:
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2603 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2604 ret i32* %reg
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2605 }
2606</pre>
2607
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2608<h5>Semantics:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2609
2610<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2611on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2612and <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]2613<a href="#t_integer">integer</a> type but the value will always be sign extended
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2614to 64-bits. <a href="#t_struct">Structure</a> types, require <tt>i32</tt>
Reid Spencerc0312692006-12-03 16:53:48 +0000[diff] [blame]2615<b>constants</b>.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2616
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2617<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]2618type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2619}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2620the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2621i8 }</tt>' type, another structure. The third index indexes into the second
2622element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2623array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2624'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2625to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2626
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2627<p>Note that it is perfectly legal to index partially through a
2628structure, returning a pointer to an inner element. Because of this,
2629the LLVM code for the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2630
2631<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2632 define i32* %foo(%ST* %s) {
2633 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
2634 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2635 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
2636 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2637 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2638 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2639 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2640</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]2641
2642<p>Note that it is undefined to access an array out of bounds: array and
2643pointer indexes must always be within the defined bounds of the array type.
2644The one exception for this rules is zero length arrays. These arrays are
2645defined to be accessible as variable length arrays, which requires access
2646beyond the zero'th element.</p>
2647
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]2648<p>The getelementptr instruction is often confusing. For some more insight
2649into how it works, see <a href="GetElementPtr.html">the getelementptr
2650FAQ</a>.</p>
2651
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2652<h5>Example:</h5>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]2653
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2654<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2655 <i>; yields [12 x i8]*:aptr</i>
2656 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2657</pre>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2658</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]2659
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2660<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]2661<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2662</div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2663<div class="doc_text">
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]2664<p>The instructions in this category are the conversion instructions (casting)
2665which all take a single operand and a type. They perform various bit conversions
2666on the operand.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2667</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2668
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2669<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2670<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2671 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2672</div>
2673<div class="doc_text">
2674
2675<h5>Syntax:</h5>
2676<pre>
2677 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2678</pre>
2679
2680<h5>Overview:</h5>
2681<p>
2682The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2683</p>
2684
2685<h5>Arguments:</h5>
2686<p>
2687The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2688be an <a href="#t_integer">integer</a> type, and a type that specifies the size
2689and type of the result, which must be an <a href="#t_integral">integral</a>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2690type. The bit size of <tt>value</tt> must be larger than the bit size of
2691<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2692
2693<h5>Semantics:</h5>
2694<p>
2695The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2696and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2697larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2698It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2699
2700<h5>Example:</h5>
2701<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2702 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
2703 %Y = trunc i32 123 to bool <i>; yields bool:true</i>
Reid Spencerdb943532007-01-05 21:33:08 +0000[diff] [blame^]2704 %Y = trunc i32 122 to bool <i>; yields bool:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2705</pre>
2706</div>
2707
2708<!-- _______________________________________________________________________ -->
2709<div class="doc_subsubsection">
2710 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2711</div>
2712<div class="doc_text">
2713
2714<h5>Syntax:</h5>
2715<pre>
2716 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2717</pre>
2718
2719<h5>Overview:</h5>
2720<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2721<tt>ty2</tt>.</p>
2722
2723
2724<h5>Arguments:</h5>
2725<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
2726<a href="#t_integral">integral</a> type, and a type to cast it to, which must
2727also be of <a href="#t_integral">integral</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2728<tt>value</tt> must be smaller than the bit size of the destination type,
2729<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2730
2731<h5>Semantics:</h5>
2732<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
2733bits until it reaches the size of the destination type, <tt>ty2</tt>. When the
2734the operand and the type are the same size, no bit filling is done and the
2735cast is considered a <i>no-op cast</i> because no bits change (only the type
2736changes).</p>
2737
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2738<p>When zero extending from bool, the result will alwasy be either 0 or 1.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2739
2740<h5>Example:</h5>
2741<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2742 %X = zext i32 257 to i64 <i>; yields i64:257</i>
2743 %Y = zext bool true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2744</pre>
2745</div>
2746
2747<!-- _______________________________________________________________________ -->
2748<div class="doc_subsubsection">
2749 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
2750</div>
2751<div class="doc_text">
2752
2753<h5>Syntax:</h5>
2754<pre>
2755 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2756</pre>
2757
2758<h5>Overview:</h5>
2759<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
2760
2761<h5>Arguments:</h5>
2762<p>
2763The '<tt>sext</tt>' instruction takes a value to cast, which must be of
2764<a href="#t_integral">integral</a> type, and a type to cast it to, which must
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2765also be of <a href="#t_integral">integral</a> type. The bit size of the
2766<tt>value</tt> must be smaller than the bit size of the destination type,
2767<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2768
2769<h5>Semantics:</h5>
2770<p>
2771The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
2772bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
2773the type <tt>ty2</tt>. When the the operand and the type are the same size,
2774no bit filling is done and the cast is considered a <i>no-op cast</i> because
2775no bits change (only the type changes).</p>
2776
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2777<p>When sign extending from bool, the extension always results in -1 or 0.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2778
2779<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2780<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2781 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
2782 %Y = sext bool true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2783</pre>
2784</div>
2785
2786<!-- _______________________________________________________________________ -->
2787<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]2788 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
2789</div>
2790
2791<div class="doc_text">
2792
2793<h5>Syntax:</h5>
2794
2795<pre>
2796 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2797</pre>
2798
2799<h5>Overview:</h5>
2800<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
2801<tt>ty2</tt>.</p>
2802
2803
2804<h5>Arguments:</h5>
2805<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
2806 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
2807cast it to. The size of <tt>value</tt> must be larger than the size of
2808<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
2809<i>no-op cast</i>.</p>
2810
2811<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2812<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
2813<a href="#t_floating">floating point</a> type to a smaller
2814<a href="#t_floating">floating point</a> type. If the value cannot fit within
2815the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]2816
2817<h5>Example:</h5>
2818<pre>
2819 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
2820 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
2821</pre>
2822</div>
2823
2824<!-- _______________________________________________________________________ -->
2825<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2826 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
2827</div>
2828<div class="doc_text">
2829
2830<h5>Syntax:</h5>
2831<pre>
2832 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2833</pre>
2834
2835<h5>Overview:</h5>
2836<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
2837floating point value.</p>
2838
2839<h5>Arguments:</h5>
2840<p>The '<tt>fpext</tt>' instruction takes a
2841<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2842and a <a href="#t_floating">floating point</a> type to cast it to. The source
2843type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2844
2845<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2846<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
2847<a href="t_floating">floating point</a> type to a larger
2848<a href="t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
2849used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2850<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]2851
2852<h5>Example:</h5>
2853<pre>
2854 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
2855 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
2856</pre>
2857</div>
2858
2859<!-- _______________________________________________________________________ -->
2860<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2861 <a name="i_fp2uint">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2862</div>
2863<div class="doc_text">
2864
2865<h5>Syntax:</h5>
2866<pre>
2867 &lt;result&gt; = fp2uint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2868</pre>
2869
2870<h5>Overview:</h5>
2871<p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its
2872unsigned integer equivalent of type <tt>ty2</tt>.
2873</p>
2874
2875<h5>Arguments:</h5>
2876<p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a
2877<a href="#t_floating">floating point</a> value, and a type to cast it to, which
2878must be an <a href="#t_integral">integral</a> type.</p>
2879
2880<h5>Semantics:</h5>
2881<p> The '<tt>fp2uint</tt>' instruction converts its
2882<a href="#t_floating">floating point</a> operand into the nearest (rounding
2883towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
2884the results are undefined.</p>
2885
2886<p>When converting to bool, the conversion is done as a comparison against
2887zero. If the <tt>value</tt> was zero, the bool result will be <tt>false</tt>.
2888If the <tt>value</tt> was non-zero, the bool result will be <tt>true</tt>.</p>
2889
2890<h5>Example:</h5>
2891<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2892 %X = fp2uint double 123.0 to i32 <i>; yields i32:123</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2893 %Y = fp2uint float 1.0E+300 to bool <i>; yields bool:true</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2894 %X = fp2uint float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2895</pre>
2896</div>
2897
2898<!-- _______________________________________________________________________ -->
2899<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2900 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2901</div>
2902<div class="doc_text">
2903
2904<h5>Syntax:</h5>
2905<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2906 &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]2907</pre>
2908
2909<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2910<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2911<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]2912</p>
2913
2914
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2915<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2916<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]2917<a href="#t_floating">floating point</a> value, and a type to cast it to, which
2918must also be an <a href="#t_integral">integral</a> type.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2919
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2920<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2921<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2922<a href="#t_floating">floating point</a> operand into the nearest (rounding
2923towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
2924the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2925
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2926<p>When converting to bool, the conversion is done as a comparison against
2927zero. If the <tt>value</tt> was zero, the bool result will be <tt>false</tt>.
2928If the <tt>value</tt> was non-zero, the bool result will be <tt>true</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2929
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]2930<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2931<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2932 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2933 %Y = fptosi float 1.0E-247 to bool <i>; yields bool:true</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2934 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2935</pre>
2936</div>
2937
2938<!-- _______________________________________________________________________ -->
2939<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2940 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2941</div>
2942<div class="doc_text">
2943
2944<h5>Syntax:</h5>
2945<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2946 &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]2947</pre>
2948
2949<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2950<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2951integer and converts that value to the <tt>ty2</tt> type.</p>
2952
2953
2954<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2955<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be an
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2956<a href="#t_integral">integral</a> value, and a type to cast it to, which must
2957be a <a href="#t_floating">floating point</a> type.</p>
2958
2959<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2960<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2961integer quantity and converts it to the corresponding floating point value. If
2962the value cannot fit in the floating point value, the results are undefined.</p>
2963
2964
2965<h5>Example:</h5>
2966<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2967 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
2968 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2969</pre>
2970</div>
2971
2972<!-- _______________________________________________________________________ -->
2973<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2974 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2975</div>
2976<div class="doc_text">
2977
2978<h5>Syntax:</h5>
2979<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2980 &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]2981</pre>
2982
2983<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2984<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2985integer and converts that value to the <tt>ty2</tt> type.</p>
2986
2987<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2988<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be an
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2989<a href="#t_integral">integral</a> value, and a type to cast it to, which must be
2990a <a href="#t_floating">floating point</a> type.</p>
2991
2992<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2993<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2994integer quantity and converts it to the corresponding floating point value. If
2995the value cannot fit in the floating point value, the results are undefined.</p>
2996
2997<h5>Example:</h5>
2998<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2999 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
3000 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3001</pre>
3002</div>
3003
3004<!-- _______________________________________________________________________ -->
3005<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3006 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3007</div>
3008<div class="doc_text">
3009
3010<h5>Syntax:</h5>
3011<pre>
3012 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3013</pre>
3014
3015<h5>Overview:</h5>
3016<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3017the integer type <tt>ty2</tt>.</p>
3018
3019<h5>Arguments:</h5>
3020<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3021must be a <a href="t_pointer">pointer</a> value, and a type to cast it to
3022<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3023
3024<h5>Semantics:</h5>
3025<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3026<tt>ty2</tt> by interpreting the pointer value as an integer and either
3027truncating or zero extending that value to the size of the integer type. If
3028<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3029<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3030are the same size, then nothing is done (<i>no-op cast</i>).</p>
3031
3032<h5>Example:</h5>
3033<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3034 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit</i>
3035 %Y = ptrtoint i32* %x to i64 <i>; yields zero extend on 32-bit</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3036</pre>
3037</div>
3038
3039<!-- _______________________________________________________________________ -->
3040<div class="doc_subsubsection">
3041 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3042</div>
3043<div class="doc_text">
3044
3045<h5>Syntax:</h5>
3046<pre>
3047 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3048</pre>
3049
3050<h5>Overview:</h5>
3051<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3052a pointer type, <tt>ty2</tt>.</p>
3053
3054<h5>Arguments:</h5>
3055<p>The '<tt>inttoptr</tt>' instruction takes an <a href="i_integer">integer</a>
3056value to cast, and a type to cast it to, which must be a
3057<a href="#t_pointer">pointer</a> type. </tt>
3058
3059<h5>Semantics:</h5>
3060<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3061<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3062the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3063size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3064the size of a pointer then a zero extension is done. If they are the same size,
3065nothing is done (<i>no-op cast</i>).</p>
3066
3067<h5>Example:</h5>
3068<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3069 %X = inttoptr i32 255 to i32* <i>; yields zero extend on 64-bit</i>
3070 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit </i>
3071 %Y = inttoptr i16 0 to i32* <i>; yields zero extend on 32-bit</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3072</pre>
3073</div>
3074
3075<!-- _______________________________________________________________________ -->
3076<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3077 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3078</div>
3079<div class="doc_text">
3080
3081<h5>Syntax:</h5>
3082<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3083 &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]3084</pre>
3085
3086<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3087<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3088<tt>ty2</tt> without changing any bits.</p>
3089
3090<h5>Arguments:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3091<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3092a first class value, and a type to cast it to, which must also be a <a
3093 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
3094and the destination type, <tt>ty2</tt>, must be identical.</p>
3095
3096<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3097<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3098<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3099this conversion. The conversion is done as if the <tt>value</tt> had been
3100stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3101converted to other pointer types with this instruction. To convert pointers to
3102other types, use the <a href="#i_inttoptr">inttoptr</a> or
3103<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3104
3105<h5>Example:</h5>
3106<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3107 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
3108 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3109 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3110</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3111</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3112
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3113<!-- ======================================================================= -->
3114<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3115<div class="doc_text">
3116<p>The instructions in this category are the "miscellaneous"
3117instructions, which defy better classification.</p>
3118</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3119
3120<!-- _______________________________________________________________________ -->
3121<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3122</div>
3123<div class="doc_text">
3124<h5>Syntax:</h5>
3125<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
3126</pre>
3127<h5>Overview:</h5>
3128<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3129of its two integer operands.</p>
3130<h5>Arguments:</h5>
3131<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
3132the condition code which indicates the kind of comparison to perform. It is not
3133a value, just a keyword. The possibilities for the condition code are:
3134<ol>
3135 <li><tt>eq</tt>: equal</li>
3136 <li><tt>ne</tt>: not equal </li>
3137 <li><tt>ugt</tt>: unsigned greater than</li>
3138 <li><tt>uge</tt>: unsigned greater or equal</li>
3139 <li><tt>ult</tt>: unsigned less than</li>
3140 <li><tt>ule</tt>: unsigned less or equal</li>
3141 <li><tt>sgt</tt>: signed greater than</li>
3142 <li><tt>sge</tt>: signed greater or equal</li>
3143 <li><tt>slt</tt>: signed less than</li>
3144 <li><tt>sle</tt>: signed less or equal</li>
3145</ol>
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3146<p>The remaining two arguments must be <a href="#t_integral">integral</a> or
3147<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3148<h5>Semantics:</h5>
3149<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3150the condition code given as <tt>cond</tt>. The comparison performed always
3151yields a <a href="#t_bool">bool</a> result, as follows:
3152<ol>
3153 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3154 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3155 </li>
3156 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3157 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3158 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3159 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3160 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3161 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3162 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3163 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3164 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3165 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3166 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3167 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3168 <li><tt>sge</tt>: interprets the operands as signed values and yields
3169 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3170 <li><tt>slt</tt>: interprets the operands as signed values and yields
3171 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3172 <li><tt>sle</tt>: interprets the operands as signed values and yields
3173 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3174 </li>
3175</ol>
3176<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
3177values are treated as integers and then compared.</p>
3178<p>If the operands are <a href="#t_packed">packed</a> typed, the elements of
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3179the vector are compared in turn and the predicate must hold for all
3180elements.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3181
3182<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3183<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3184 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3185 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3186 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3187 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3188 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3189</pre>
3190</div>
3191
3192<!-- _______________________________________________________________________ -->
3193<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3194</div>
3195<div class="doc_text">
3196<h5>Syntax:</h5>
3197<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
3198</pre>
3199<h5>Overview:</h5>
3200<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3201of its floating point operands.</p>
3202<h5>Arguments:</h5>
3203<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
3204the condition code which indicates the kind of comparison to perform. It is not
3205a value, just a keyword. The possibilities for the condition code are:
3206<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3207 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3208 <li><tt>oeq</tt>: ordered and equal</li>
3209 <li><tt>ogt</tt>: ordered and greater than </li>
3210 <li><tt>oge</tt>: ordered and greater than or equal</li>
3211 <li><tt>olt</tt>: ordered and less than </li>
3212 <li><tt>ole</tt>: ordered and less than or equal</li>
3213 <li><tt>one</tt>: ordered and not equal</li>
3214 <li><tt>ord</tt>: ordered (no nans)</li>
3215 <li><tt>ueq</tt>: unordered or equal</li>
3216 <li><tt>ugt</tt>: unordered or greater than </li>
3217 <li><tt>uge</tt>: unordered or greater than or equal</li>
3218 <li><tt>ult</tt>: unordered or less than </li>
3219 <li><tt>ule</tt>: unordered or less than or equal</li>
3220 <li><tt>une</tt>: unordered or not equal</li>
3221 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3222 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3223</ol>
Reid Spencer02e0d1d2006-12-06 07:08:07 +0000[diff] [blame]3224<p>In the preceding, <i>ordered</i> means that neither operand is a QNAN while
3225<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3226<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3227<a href="#t_floating">floating point</a> typed. They must have identical
3228types.</p>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3229<p>In the foregoing, <i>ordered</i> means that neither operand is a QNAN and
3230<i>unordered</i> means that either operand is a QNAN.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3231<h5>Semantics:</h5>
3232<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3233the condition code given as <tt>cond</tt>. The comparison performed always
3234yields a <a href="#t_bool">bool</a> result, as follows:
3235<ol>
3236 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3237 <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]3238 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3239 <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]3240 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3241 <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]3242 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3243 <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]3244 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3245 <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]3246 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3247 <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]3248 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3249 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3250 <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]3251 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3252 <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]3253 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3254 <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]3255 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3256 <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]3257 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3258 <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]3259 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3260 <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]3261 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3262 <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]3263 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3264</ol>
3265<p>If the operands are <a href="#t_packed">packed</a> typed, the elements of
3266the vector are compared in turn and the predicate must hold for all elements.
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3267</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3268
3269<h5>Example:</h5>
3270<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3271 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3272 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3273 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3274</pre>
3275</div>
3276
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3277<!-- _______________________________________________________________________ -->
3278<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3279Instruction</a> </div>
3280<div class="doc_text">
3281<h5>Syntax:</h5>
3282<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3283<h5>Overview:</h5>
3284<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3285the SSA graph representing the function.</p>
3286<h5>Arguments:</h5>
3287<p>The type of the incoming values are specified with the first type
3288field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3289as arguments, with one pair for each predecessor basic block of the
3290current block. Only values of <a href="#t_firstclass">first class</a>
3291type may be used as the value arguments to the PHI node. Only labels
3292may be used as the label arguments.</p>
3293<p>There must be no non-phi instructions between the start of a basic
3294block and the PHI instructions: i.e. PHI instructions must be first in
3295a basic block.</p>
3296<h5>Semantics:</h5>
3297<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
3298value specified by the parameter, depending on which basic block we
3299came from in the last <a href="#terminators">terminator</a> instruction.</p>
3300<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3301<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]3302</div>
3303
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3304<!-- _______________________________________________________________________ -->
3305<div class="doc_subsubsection">
3306 <a name="i_select">'<tt>select</tt>' Instruction</a>
3307</div>
3308
3309<div class="doc_text">
3310
3311<h5>Syntax:</h5>
3312
3313<pre>
3314 &lt;result&gt; = select bool &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
3315</pre>
3316
3317<h5>Overview:</h5>
3318
3319<p>
3320The '<tt>select</tt>' instruction is used to choose one value based on a
3321condition, without branching.
3322</p>
3323
3324
3325<h5>Arguments:</h5>
3326
3327<p>
3328The '<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.
3329</p>
3330
3331<h5>Semantics:</h5>
3332
3333<p>
3334If the boolean condition evaluates to true, the instruction returns the first
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3335value argument; otherwise, it returns the second value argument.
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3336</p>
3337
3338<h5>Example:</h5>
3339
3340<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3341 %X = select bool true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3342</pre>
3343</div>
3344
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]3345
3346<!-- _______________________________________________________________________ -->
3347<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3348 <a name="i_call">'<tt>call</tt>' Instruction</a>
3349</div>
3350
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3351<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3352
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3353<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3354<pre>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3355 &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]3356</pre>
3357
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3358<h5>Overview:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3359
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3360<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3361
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3362<h5>Arguments:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3363
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3364<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3365
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3366<ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3367 <li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3368 <p>The optional "tail" marker indicates whether the callee function accesses
3369 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3370 function call is eligible for tail call optimization. Note that calls may
3371 be marked "tail" even if they do not occur before a <a
3372 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3373 </li>
3374 <li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3375 <p>The optional "cconv" marker indicates which <a href="callingconv">calling
3376 convention</a> the call should use. If none is specified, the call defaults
3377 to using C calling conventions.
3378 </li>
3379 <li>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3380 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
3381 being invoked. The argument types must match the types implied by this
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3382 signature. This type can be omitted if the function is not varargs and
3383 if the function type does not return a pointer to a function.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3384 </li>
3385 <li>
3386 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3387 be invoked. In most cases, this is a direct function invocation, but
3388 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3389 to function value.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3390 </li>
3391 <li>
3392 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencerd845d162005-05-01 22:22:57 +0000[diff] [blame]3393 function signature argument types. All arguments must be of
3394 <a href="#t_firstclass">first class</a> type. If the function signature
3395 indicates the function accepts a variable number of arguments, the extra
3396 arguments can be specified.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3397 </li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3398</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3399
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3400<h5>Semantics:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3401
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3402<p>The '<tt>call</tt>' instruction is used to cause control flow to
3403transfer to a specified function, with its incoming arguments bound to
3404the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3405instruction in the called function, control flow continues with the
3406instruction after the function call, and the return value of the
3407function is bound to the result argument. This is a simpler case of
3408the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3409
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3410<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3411
3412<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3413 %retval = call i32 %test(i32 %argc)
3414 call i32(i8 *, ...) *%printf(i8 * %msg, i32 12, i8 42);
3415 %X = tail call i32 %foo()
3416 %Y = tail call <a href="#callingconv">fastcc</a> i32 %foo()
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3417</pre>
3418
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3419</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3420
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3421<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3422<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]3423 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3424</div>
3425
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3426<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3427
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3428<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3429
3430<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3431 &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]3432</pre>
3433
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3434<h5>Overview:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3435
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3436<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3437the "variable argument" area of a function call. It is used to implement the
3438<tt>va_arg</tt> macro in C.</p>
3439
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3440<h5>Arguments:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3441
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3442<p>This instruction takes a <tt>va_list*</tt> value and the type of
3443the argument. It returns a value of the specified argument type and
Jeff Cohendc6bfea2005-11-11 02:15:27 +0000[diff] [blame]3444increments the <tt>va_list</tt> to point to the next argument. Again, the
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3445actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3446
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3447<h5>Semantics:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3448
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3449<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3450type from the specified <tt>va_list</tt> and causes the
3451<tt>va_list</tt> to point to the next argument. For more information,
3452see the variable argument handling <a href="#int_varargs">Intrinsic
3453Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3454
3455<p>It is legal for this instruction to be called in a function which does not
3456take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3457function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3458
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3459<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3460href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3461argument.</p>
3462
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3463<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3464
3465<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3466
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3467</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3468
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3469<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3470<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3471<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3472
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3473<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3474
3475<p>LLVM supports the notion of an "intrinsic function". These functions have
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3476well known names and semantics and are required to follow certain
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3477restrictions. Overall, these instructions represent an extension mechanism for
3478the LLVM language that does not require changing all of the transformations in
3479LLVM to add to the language (or the bytecode reader/writer, the parser,
3480etc...).</p>
3481
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3482<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
3483prefix is reserved in LLVM for intrinsic names; thus, functions may not be named
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3484this. Intrinsic functions must always be external functions: you cannot define
3485the body of intrinsic functions. Intrinsic functions may only be used in call
3486or invoke instructions: it is illegal to take the address of an intrinsic
3487function. Additionally, because intrinsic functions are part of the LLVM
3488language, it is required that they all be documented here if any are added.</p>
3489
3490
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3491<p>To learn how to add an intrinsic function, please see the <a
Chris Lattner90391c12005-05-11 03:35:57 +0000[diff] [blame]3492href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3493</p>
3494
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3495</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3496
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3497<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3498<div class="doc_subsection">
3499 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3500</div>
3501
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3502<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3503
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3504<p>Variable argument support is defined in LLVM with the <a
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]3505 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3506intrinsic functions. These functions are related to the similarly
3507named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3508
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3509<p>All of these functions operate on arguments that use a
3510target-specific value type "<tt>va_list</tt>". The LLVM assembly
3511language reference manual does not define what this type is, so all
3512transformations should be prepared to handle intrinsics with any type
3513used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3514
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]3515<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]3516instruction and the variable argument handling intrinsic functions are
3517used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3518
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3519<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3520define i32 %test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3521 ; Initialize variable argument processing
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3522 %ap = alloca i8 *
3523 call void %<a href="#i_va_start">llvm.va_start</a>(i8 ** %ap)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3524
3525 ; Read a single integer argument
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3526 %tmp = va_arg i8 ** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3527
3528 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3529 %aq = alloca i8 *
3530 call void %<a href="#i_va_copy">llvm.va_copy</a>(i8 ** %aq, i8 ** %ap)
3531 call void %<a href="#i_va_end">llvm.va_end</a>(i8 ** %aq)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3532
3533 ; Stop processing of arguments.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3534 call void %<a href="#i_va_end">llvm.va_end</a>(i8 ** %ap)
3535 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3536}
3537</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3538</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3539
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3540<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3541<div class="doc_subsubsection">
3542 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
3543</div>
3544
3545
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3546<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3547<h5>Syntax:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3548<pre> declare void %llvm.va_start(&lt;va_list&gt;* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3549<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3550<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3551<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3552href="#i_va_arg">va_arg</a></tt>.</p>
3553
3554<h5>Arguments:</h5>
3555
3556<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3557
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3558<h5>Semantics:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3559
3560<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3561macro available in C. In a target-dependent way, it initializes the
3562<tt>va_list</tt> element the argument points to, so that the next call to
3563<tt>va_arg</tt> will produce the first variable argument passed to the function.
3564Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
3565last argument of the function, the compiler can figure that out.</p>
3566
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3567</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3568
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3569<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3570<div class="doc_subsubsection">
3571 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
3572</div>
3573
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3574<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3575<h5>Syntax:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3576<pre> declare void %llvm.va_end(&lt;va_list*&gt; &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3577<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3578<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
3579which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
3580or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3581<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3582<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3583<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3584<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3585macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
3586Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
3587 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
3588with calls to <tt>llvm.va_end</tt>.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3589</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3590
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3591<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3592<div class="doc_subsubsection">
3593 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
3594</div>
3595
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3596<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3597
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3598<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3599
3600<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3601 declare void %llvm.va_copy(&lt;va_list&gt;* &lt;destarglist&gt;,
Andrew Lenharth5305ea52005-06-22 20:38:11 +0000[diff] [blame]3602 &lt;va_list&gt;* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3603</pre>
3604
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3605<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3606
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3607<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from
3608the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3609
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3610<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3611
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3612<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]3613The 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]3614
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3615
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3616<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3617
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3618<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro
3619available in C. In a target-dependent way, it copies the source
3620<tt>va_list</tt> element into the destination list. This intrinsic is necessary
3621because the <tt><a href="i_va_begin">llvm.va_begin</a></tt> intrinsic may be
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3622arbitrarily complex and require memory allocation, for example.</p>
3623
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3624</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3625
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3626<!-- ======================================================================= -->
3627<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3628 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3629</div>
3630
3631<div class="doc_text">
3632
3633<p>
3634LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3635Collection</a> requires the implementation and generation of these intrinsics.
3636These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
3637stack</a>, as well as garbage collector implementations that require <a
3638href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
3639Front-ends for type-safe garbage collected languages should generate these
3640intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3641href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3642</p>
3643</div>
3644
3645<!-- _______________________________________________________________________ -->
3646<div class="doc_subsubsection">
3647 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
3648</div>
3649
3650<div class="doc_text">
3651
3652<h5>Syntax:</h5>
3653
3654<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]3655 declare void %llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3656</pre>
3657
3658<h5>Overview:</h5>
3659
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]3660<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]3661the code generator, and allows some metadata to be associated with it.</p>
3662
3663<h5>Arguments:</h5>
3664
3665<p>The first argument specifies the address of a stack object that contains the
3666root pointer. The second pointer (which must be either a constant or a global
3667value address) contains the meta-data to be associated with the root.</p>
3668
3669<h5>Semantics:</h5>
3670
3671<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3672location. At compile-time, the code generator generates information to allow
3673the runtime to find the pointer at GC safe points.
3674</p>
3675
3676</div>
3677
3678
3679<!-- _______________________________________________________________________ -->
3680<div class="doc_subsubsection">
3681 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
3682</div>
3683
3684<div class="doc_text">
3685
3686<h5>Syntax:</h5>
3687
3688<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3689 declare i8 * %llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3690</pre>
3691
3692<h5>Overview:</h5>
3693
3694<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3695locations, allowing garbage collector implementations that require read
3696barriers.</p>
3697
3698<h5>Arguments:</h5>
3699
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]3700<p>The second argument is the address to read from, which should be an address
3701allocated from the garbage collector. The first object is a pointer to the
3702start of the referenced object, if needed by the language runtime (otherwise
3703null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3704
3705<h5>Semantics:</h5>
3706
3707<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3708instruction, but may be replaced with substantially more complex code by the
3709garbage collector runtime, as needed.</p>
3710
3711</div>
3712
3713
3714<!-- _______________________________________________________________________ -->
3715<div class="doc_subsubsection">
3716 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
3717</div>
3718
3719<div class="doc_text">
3720
3721<h5>Syntax:</h5>
3722
3723<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3724 declare void %llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3725</pre>
3726
3727<h5>Overview:</h5>
3728
3729<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3730locations, allowing garbage collector implementations that require write
3731barriers (such as generational or reference counting collectors).</p>
3732
3733<h5>Arguments:</h5>
3734
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]3735<p>The first argument is the reference to store, the second is the start of the
3736object to store it to, and the third is the address of the field of Obj to
3737store to. If the runtime does not require a pointer to the object, Obj may be
3738null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3739
3740<h5>Semantics:</h5>
3741
3742<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3743instruction, but may be replaced with substantially more complex code by the
3744garbage collector runtime, as needed.</p>
3745
3746</div>
3747
3748
3749
3750<!-- ======================================================================= -->
3751<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3752 <a name="int_codegen">Code Generator Intrinsics</a>
3753</div>
3754
3755<div class="doc_text">
3756<p>
3757These intrinsics are provided by LLVM to expose special features that may only
3758be implemented with code generator support.
3759</p>
3760
3761</div>
3762
3763<!-- _______________________________________________________________________ -->
3764<div class="doc_subsubsection">
3765 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
3766</div>
3767
3768<div class="doc_text">
3769
3770<h5>Syntax:</h5>
3771<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3772 declare i8 *%llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3773</pre>
3774
3775<h5>Overview:</h5>
3776
3777<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]3778The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
3779target-specific value indicating the return address of the current function
3780or one of its callers.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3781</p>
3782
3783<h5>Arguments:</h5>
3784
3785<p>
3786The argument to this intrinsic indicates which function to return the address
3787for. Zero indicates the calling function, one indicates its caller, etc. The
3788argument is <b>required</b> to be a constant integer value.
3789</p>
3790
3791<h5>Semantics:</h5>
3792
3793<p>
3794The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
3795the return address of the specified call frame, or zero if it cannot be
3796identified. The value returned by this intrinsic is likely to be incorrect or 0
3797for arguments other than zero, so it should only be used for debugging purposes.
3798</p>
3799
3800<p>
3801Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]3802aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3803source-language caller.
3804</p>
3805</div>
3806
3807
3808<!-- _______________________________________________________________________ -->
3809<div class="doc_subsubsection">
3810 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
3811</div>
3812
3813<div class="doc_text">
3814
3815<h5>Syntax:</h5>
3816<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3817 declare i8 *%llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3818</pre>
3819
3820<h5>Overview:</h5>
3821
3822<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]3823The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
3824target-specific frame pointer value for the specified stack frame.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3825</p>
3826
3827<h5>Arguments:</h5>
3828
3829<p>
3830The argument to this intrinsic indicates which function to return the frame
3831pointer for. Zero indicates the calling function, one indicates its caller,
3832etc. The argument is <b>required</b> to be a constant integer value.
3833</p>
3834
3835<h5>Semantics:</h5>
3836
3837<p>
3838The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
3839the frame address of the specified call frame, or zero if it cannot be
3840identified. The value returned by this intrinsic is likely to be incorrect or 0
3841for arguments other than zero, so it should only be used for debugging purposes.
3842</p>
3843
3844<p>
3845Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]3846aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3847source-language caller.
3848</p>
3849</div>
3850
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]3851<!-- _______________________________________________________________________ -->
3852<div class="doc_subsubsection">
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]3853 <a name="i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
3854</div>
3855
3856<div class="doc_text">
3857
3858<h5>Syntax:</h5>
3859<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3860 declare i8 *%llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]3861</pre>
3862
3863<h5>Overview:</h5>
3864
3865<p>
3866The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
3867the function stack, for use with <a href="#i_stackrestore">
3868<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
3869features like scoped automatic variable sized arrays in C99.
3870</p>
3871
3872<h5>Semantics:</h5>
3873
3874<p>
3875This intrinsic returns a opaque pointer value that can be passed to <a
3876href="#i_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
3877<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
3878<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
3879state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
3880practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
3881that were allocated after the <tt>llvm.stacksave</tt> was executed.
3882</p>
3883
3884</div>
3885
3886<!-- _______________________________________________________________________ -->
3887<div class="doc_subsubsection">
3888 <a name="i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
3889</div>
3890
3891<div class="doc_text">
3892
3893<h5>Syntax:</h5>
3894<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3895 declare void %llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]3896</pre>
3897
3898<h5>Overview:</h5>
3899
3900<p>
3901The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
3902the function stack to the state it was in when the corresponding <a
3903href="#llvm.stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
3904useful for implementing language features like scoped automatic variable sized
3905arrays in C99.
3906</p>
3907
3908<h5>Semantics:</h5>
3909
3910<p>
3911See the description for <a href="#i_stacksave"><tt>llvm.stacksave</tt></a>.
3912</p>
3913
3914</div>
3915
3916
3917<!-- _______________________________________________________________________ -->
3918<div class="doc_subsubsection">
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]3919 <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
3920</div>
3921
3922<div class="doc_text">
3923
3924<h5>Syntax:</h5>
3925<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3926 declare void %llvm.prefetch(i8 * &lt;address&gt;,
3927 i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]3928</pre>
3929
3930<h5>Overview:</h5>
3931
3932
3933<p>
3934The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3935a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
3936no
3937effect on the behavior of the program but can change its performance
Chris Lattnerff851072005-02-28 19:47:14 +0000[diff] [blame]3938characteristics.
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]3939</p>
3940
3941<h5>Arguments:</h5>
3942
3943<p>
3944<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
3945determining if the fetch should be for a read (0) or write (1), and
3946<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattnerd3e641c2005-03-07 20:31:38 +0000[diff] [blame]3947locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]3948<tt>locality</tt> arguments must be constant integers.
3949</p>
3950
3951<h5>Semantics:</h5>
3952
3953<p>
3954This intrinsic does not modify the behavior of the program. In particular,
3955prefetches cannot trap and do not produce a value. On targets that support this
3956intrinsic, the prefetch can provide hints to the processor cache for better
3957performance.
3958</p>
3959
3960</div>
3961
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]3962<!-- _______________________________________________________________________ -->
3963<div class="doc_subsubsection">
3964 <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
3965</div>
3966
3967<div class="doc_text">
3968
3969<h5>Syntax:</h5>
3970<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3971 declare void %llvm.pcmarker( i32 &lt;id&gt; )
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]3972</pre>
3973
3974<h5>Overview:</h5>
3975
3976
3977<p>
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3978The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
3979(PC) in a region of
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]3980code to simulators and other tools. The method is target specific, but it is
3981expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohendc6bfea2005-11-11 02:15:27 +0000[diff] [blame]3982The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnere64d41d2005-11-15 06:07:55 +0000[diff] [blame]3983after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb40261e2006-03-24 07:16:10 +0000[diff] [blame]3984optimizations. The intended use is to be inserted after optimizations to allow
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3985correlations of simulation runs.
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]3986</p>
3987
3988<h5>Arguments:</h5>
3989
3990<p>
3991<tt>id</tt> is a numerical id identifying the marker.
3992</p>
3993
3994<h5>Semantics:</h5>
3995
3996<p>
3997This intrinsic does not modify the behavior of the program. Backends that do not
3998support this intrinisic may ignore it.
3999</p>
4000
4001</div>
4002
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4003<!-- _______________________________________________________________________ -->
4004<div class="doc_subsubsection">
4005 <a name="i_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
4006</div>
4007
4008<div class="doc_text">
4009
4010<h5>Syntax:</h5>
4011<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4012 declare i64 %llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4013</pre>
4014
4015<h5>Overview:</h5>
4016
4017
4018<p>
4019The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4020counter register (or similar low latency, high accuracy clocks) on those targets
4021that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4022As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4023should only be used for small timings.
4024</p>
4025
4026<h5>Semantics:</h5>
4027
4028<p>
4029When directly supported, reading the cycle counter should not modify any memory.
4030Implementations are allowed to either return a application specific value or a
4031system wide value. On backends without support, this is lowered to a constant 0.
4032</p>
4033
4034</div>
4035
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4036<!-- ======================================================================= -->
4037<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4038 <a name="int_libc">Standard C Library Intrinsics</a>
4039</div>
4040
4041<div class="doc_text">
4042<p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4043LLVM provides intrinsics for a few important standard C library functions.
4044These intrinsics allow source-language front-ends to pass information about the
4045alignment of the pointer arguments to the code generator, providing opportunity
4046for more efficient code generation.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4047</p>
4048
4049</div>
4050
4051<!-- _______________________________________________________________________ -->
4052<div class="doc_subsubsection">
4053 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
4054</div>
4055
4056<div class="doc_text">
4057
4058<h5>Syntax:</h5>
4059<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4060 declare void %llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4061 i32 &lt;len&gt;, i32 &lt;align&gt;)
4062 declare void %llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4063 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4064</pre>
4065
4066<h5>Overview:</h5>
4067
4068<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4069The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4070location to the destination location.
4071</p>
4072
4073<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4074Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4075intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4076</p>
4077
4078<h5>Arguments:</h5>
4079
4080<p>
4081The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4082the source. The third argument is an integer argument
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4083specifying the number of bytes to copy, and the fourth argument is the alignment
4084of the source and destination locations.
4085</p>
4086
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4087<p>
4088If 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]4089the caller guarantees that both the source and destination pointers are aligned
4090to that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4091</p>
4092
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4093<h5>Semantics:</h5>
4094
4095<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4096The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4097location to the destination location, which are not allowed to overlap. It
4098copies "len" bytes of memory over. If the argument is known to be aligned to
4099some boundary, this can be specified as the fourth argument, otherwise it should
4100be set to 0 or 1.
4101</p>
4102</div>
4103
4104
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4105<!-- _______________________________________________________________________ -->
4106<div class="doc_subsubsection">
4107 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
4108</div>
4109
4110<div class="doc_text">
4111
4112<h5>Syntax:</h5>
4113<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4114 declare void %llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4115 i32 &lt;len&gt;, i32 &lt;align&gt;)
4116 declare void %llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4117 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4118</pre>
4119
4120<h5>Overview:</h5>
4121
4122<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4123The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4124location to the destination location. It is similar to the
4125'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4126</p>
4127
4128<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4129Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4130intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4131</p>
4132
4133<h5>Arguments:</h5>
4134
4135<p>
4136The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4137the source. The third argument is an integer argument
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4138specifying the number of bytes to copy, and the fourth argument is the alignment
4139of the source and destination locations.
4140</p>
4141
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4142<p>
4143If 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]4144the caller guarantees that the source and destination pointers are aligned to
4145that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4146</p>
4147
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4148<h5>Semantics:</h5>
4149
4150<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4151The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4152location to the destination location, which may overlap. It
4153copies "len" bytes of memory over. If the argument is known to be aligned to
4154some boundary, this can be specified as the fourth argument, otherwise it should
4155be set to 0 or 1.
4156</p>
4157</div>
4158
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4159
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4160<!-- _______________________________________________________________________ -->
4161<div class="doc_subsubsection">
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4162 <a name="i_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4163</div>
4164
4165<div class="doc_text">
4166
4167<h5>Syntax:</h5>
4168<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4169 declare void %llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
4170 i32 &lt;len&gt;, i32 &lt;align&gt;)
4171 declare void %llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
4172 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4173</pre>
4174
4175<h5>Overview:</h5>
4176
4177<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4178The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4179byte value.
4180</p>
4181
4182<p>
4183Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4184does not return a value, and takes an extra alignment argument.
4185</p>
4186
4187<h5>Arguments:</h5>
4188
4189<p>
4190The first argument is a pointer to the destination to fill, the second is the
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4191byte value to fill it with, the third argument is an integer
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4192argument specifying the number of bytes to fill, and the fourth argument is the
4193known alignment of destination location.
4194</p>
4195
4196<p>
4197If 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]4198the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4199</p>
4200
4201<h5>Semantics:</h5>
4202
4203<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4204The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4205the
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4206destination location. If the argument is known to be aligned to some boundary,
4207this can be specified as the fourth argument, otherwise it should be set to 0 or
42081.
4209</p>
4210</div>
4211
4212
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]4213<!-- _______________________________________________________________________ -->
4214<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4215 <a name="i_isunordered">'<tt>llvm.isunordered.*</tt>' Intrinsic</a>
Alkis Evlogimenos0fa39232004-06-13 01:16:15 +0000[diff] [blame]4216</div>
4217
4218<div class="doc_text">
4219
4220<h5>Syntax:</h5>
4221<pre>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4222 declare bool %llvm.isunordered.f32(float Val1, float Val2)
4223 declare bool %llvm.isunordered.f64(double Val1, double Val2)
Alkis Evlogimenos0fa39232004-06-13 01:16:15 +0000[diff] [blame]4224</pre>
4225
4226<h5>Overview:</h5>
4227
4228<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4229The '<tt>llvm.isunordered</tt>' intrinsics return true if either or both of the
Alkis Evlogimenos0fa39232004-06-13 01:16:15 +0000[diff] [blame]4230specified floating point values is a NAN.
4231</p>
4232
4233<h5>Arguments:</h5>
4234
4235<p>
4236The arguments are floating point numbers of the same type.
4237</p>
4238
4239<h5>Semantics:</h5>
4240
4241<p>
4242If either or both of the arguments is a SNAN or QNAN, it returns true, otherwise
4243false.
4244</p>
4245</div>
4246
4247
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4248<!-- _______________________________________________________________________ -->
4249<div class="doc_subsubsection">
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]4250 <a name="i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4251</div>
4252
4253<div class="doc_text">
4254
4255<h5>Syntax:</h5>
4256<pre>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4257 declare float %llvm.sqrt.f32(float %Val)
4258 declare double %llvm.sqrt.f64(double %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4259</pre>
4260
4261<h5>Overview:</h5>
4262
4263<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4264The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4265returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
4266<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4267negative numbers (which allows for better optimization).
4268</p>
4269
4270<h5>Arguments:</h5>
4271
4272<p>
4273The argument and return value are floating point numbers of the same type.
4274</p>
4275
4276<h5>Semantics:</h5>
4277
4278<p>
4279This function returns the sqrt of the specified operand if it is a positive
4280floating point number.
4281</p>
4282</div>
4283
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4284<!-- _______________________________________________________________________ -->
4285<div class="doc_subsubsection">
4286 <a name="i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
4287</div>
4288
4289<div class="doc_text">
4290
4291<h5>Syntax:</h5>
4292<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4293 declare float %llvm.powi.f32(float %Val, i32 %power)
4294 declare double %llvm.powi.f64(double %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4295</pre>
4296
4297<h5>Overview:</h5>
4298
4299<p>
4300The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4301specified (positive or negative) power. The order of evaluation of
4302multiplications is not defined.
4303</p>
4304
4305<h5>Arguments:</h5>
4306
4307<p>
4308The second argument is an integer power, and the first is a value to raise to
4309that power.
4310</p>
4311
4312<h5>Semantics:</h5>
4313
4314<p>
4315This function returns the first value raised to the second power with an
4316unspecified sequence of rounding operations.</p>
4317</div>
4318
4319
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4320<!-- ======================================================================= -->
4321<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4322 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4323</div>
4324
4325<div class="doc_text">
4326<p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4327LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4328These allow efficient code generation for some algorithms.
4329</p>
4330
4331</div>
4332
4333<!-- _______________________________________________________________________ -->
4334<div class="doc_subsubsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4335 <a name="i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
4336</div>
4337
4338<div class="doc_text">
4339
4340<h5>Syntax:</h5>
4341<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4342 declare i16 %llvm.bswap.i16(i16 &lt;id&gt;)
4343 declare i32 %llvm.bswap.i32(i32 &lt;id&gt;)
4344 declare i64 %llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4345</pre>
4346
4347<h5>Overview:</h5>
4348
4349<p>
4350The '<tt>llvm.bwsap</tt>' family of intrinsics is used to byteswap a 16, 32 or
435164 bit quantity. These are useful for performing operations on data that is not
4352in the target's native byte order.
4353</p>
4354
4355<h5>Semantics:</h5>
4356
4357<p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4358The <tt>llvm.bswap.16</tt> intrinsic returns an i16 value that has the high
4359and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4360intrinsic returns an i32 value that has the four bytes of the input i32
4361swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
4362i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i64</tt>
4363intrinsic extends this concept to 64 bits.
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4364</p>
4365
4366</div>
4367
4368<!-- _______________________________________________________________________ -->
4369<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4370 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4371</div>
4372
4373<div class="doc_text">
4374
4375<h5>Syntax:</h5>
4376<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4377 declare i8 %llvm.ctpop.i8 (i8 &lt;src&gt;)
4378 declare i16 %llvm.ctpop.i16(i16 &lt;src&gt;)
4379 declare i32 %llvm.ctpop.i32(i32 &lt;src&gt;)
4380 declare i64 %llvm.ctpop.i64(i64 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4381</pre>
4382
4383<h5>Overview:</h5>
4384
4385<p>
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]4386The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4387value.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4388</p>
4389
4390<h5>Arguments:</h5>
4391
4392<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]4393The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]4394integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4395</p>
4396
4397<h5>Semantics:</h5>
4398
4399<p>
4400The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4401</p>
4402</div>
4403
4404<!-- _______________________________________________________________________ -->
4405<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]4406 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4407</div>
4408
4409<div class="doc_text">
4410
4411<h5>Syntax:</h5>
4412<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4413 declare i8 %llvm.ctlz.i8 (i8 &lt;src&gt;)
4414 declare i16 %llvm.ctlz.i16(i16 &lt;src&gt;)
4415 declare i32 %llvm.ctlz.i32(i32 &lt;src&gt;)
4416 declare i64 %llvm.ctlz.i64(i64 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4417</pre>
4418
4419<h5>Overview:</h5>
4420
4421<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4422The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4423leading zeros in a variable.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4424</p>
4425
4426<h5>Arguments:</h5>
4427
4428<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]4429The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]4430integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4431</p>
4432
4433<h5>Semantics:</h5>
4434
4435<p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4436The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4437in 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]4438of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4439</p>
4440</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]4441
4442
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4443
4444<!-- _______________________________________________________________________ -->
4445<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]4446 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4447</div>
4448
4449<div class="doc_text">
4450
4451<h5>Syntax:</h5>
4452<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4453 declare i8 %llvm.cttz.i8 (i8 &lt;src&gt;)
4454 declare i16 %llvm.cttz.i16(i16 &lt;src&gt;)
4455 declare i32 %llvm.cttz.i32(i32 &lt;src&gt;)
4456 declare i64 %llvm.cttz.i64(i64 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4457</pre>
4458
4459<h5>Overview:</h5>
4460
4461<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4462The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4463trailing zeros.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4464</p>
4465
4466<h5>Arguments:</h5>
4467
4468<p>
4469The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]4470integer type. The return type must match the argument type.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4471</p>
4472
4473<h5>Semantics:</h5>
4474
4475<p>
4476The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4477in a variable. If the src == 0 then the result is the size in bits of the type
4478of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4479</p>
4480</div>
4481
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4482<!-- ======================================================================= -->
4483<div class="doc_subsection">
4484 <a name="int_debugger">Debugger Intrinsics</a>
4485</div>
4486
4487<div class="doc_text">
4488<p>
4489The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4490are described in the <a
4491href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4492Debugging</a> document.
4493</p>
4494</div>
4495
4496
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4497<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4498<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]4499<address>
4500 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
4501 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
4502 <a href="http://validator.w3.org/check/referer"><img
4503 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
4504
4505 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]4506 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]4507 Last modified: $Date$
4508</address>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4509</body>
4510</html>