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gerrit-public.fairphone.software / toolchain / llvm-project / 86e01198225f9a84d2f783dd00a180823e5bda29 / . / llvm / docs / LangRef.html
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5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
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11</head>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]26 <li><a href="#functionstructure">Functions</a></li>
Anton Korobeynikov546ea7e2007-04-29 18:02:48 +0000[diff] [blame]27 <li><a href="#aliasstructure">Aliases</a>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]28 <li><a href="#paramattrs">Parameter Attributes</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]29 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]30 <li><a href="#datalayout">Data Layout</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]31 </ol>
32 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]33 <li><a href="#typesystem">Type System</a>
34 <ol>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]35 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]36 <ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]37 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]38 </ol>
39 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]40 <li><a href="#t_derived">Derived Types</a>
41 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]42 <li><a href="#t_array">Array Type</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]43 <li><a href="#t_function">Function Type</a></li>
44 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]45 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]46 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]47 <li><a href="#t_vector">Vector Type</a></li>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]48 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]49 </ol>
50 </li>
51 </ol>
52 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]53 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]54 <ol>
55 <li><a href="#simpleconstants">Simple Constants</a>
56 <li><a href="#aggregateconstants">Aggregate Constants</a>
57 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
58 <li><a href="#undefvalues">Undefined Values</a>
59 <li><a href="#constantexprs">Constant Expressions</a>
60 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]61 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]62 <li><a href="#othervalues">Other Values</a>
63 <ol>
64 <li><a href="#inlineasm">Inline Assembler Expressions</a>
65 </ol>
66 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]67 <li><a href="#instref">Instruction Reference</a>
68 <ol>
69 <li><a href="#terminators">Terminator Instructions</a>
70 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]71 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
72 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]73 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
74 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]75 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]76 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]77 </ol>
78 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]79 <li><a href="#binaryops">Binary Operations</a>
80 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]81 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
82 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
83 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]84 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
85 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
86 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]87 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
88 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
89 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]90 </ol>
91 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]92 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
93 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]94 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
95 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
96 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]97 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]98 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]99 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]100 </ol>
101 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]102 <li><a href="#vectorops">Vector Operations</a>
103 <ol>
104 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
105 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
106 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]107 </ol>
108 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]109 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]110 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]111 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
112 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
113 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]114 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
115 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
116 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]117 </ol>
118 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]119 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]120 <ol>
121 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
122 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
123 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
124 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
125 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]126 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
127 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
128 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
129 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]130 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
131 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]132 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]133 </ol>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]134 <li><a href="#otherops">Other Operations</a>
135 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]136 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
137 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]138 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]139 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]140 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]141 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]142 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]143 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]144 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]145 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]146 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]147 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]148 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
149 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]150 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
151 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
152 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]153 </ol>
154 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]155 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
156 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]157 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
158 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
159 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]160 </ol>
161 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]162 <li><a href="#int_codegen">Code Generator Intrinsics</a>
163 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]164 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
165 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
166 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
167 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
168 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
169 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
170 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]171 </ol>
172 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]173 <li><a href="#int_libc">Standard C Library Intrinsics</a>
174 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]175 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
176 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
177 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
178 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
179 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]180 </ol>
181 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]182 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]183 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]184 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]185 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
186 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
187 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]188 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
189 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]190 </ol>
191 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]192 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]193 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]194 <li><a href="#int_atomics">Atomic Operations and Synchronization Intrinsics</a>
195 <ol>
196 <li><a href="#int_lcs">'<tt>llvm.atomic.lcs.*</tt>' Intrinsic</a></li>
197 <li><a href="#int_ls">'<tt>llvm.atomic.ls.*</tt>' Intrinsic</a></li>
198 <li><a href="#int_las">'<tt>llvm.atomic.las.*</tt>' Intrinsic</a></li>
199 <li><a href="#int_lss">'<tt>llvm.atomic.lss.*</tt>' Intrinsic</a></li>
200 <li><a href="#int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a></li>
201 </ol>
202 </li>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame^]203 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]204 <ol>
205 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]206 </ol>
207 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]208 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]209 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]210 <li><a href="#int_var_annotation">
211 <tt>llvm.var.annotation</tt>' Intrinsic</a></li>
212 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]213 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]214 </ol>
215 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]216</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]217
218<div class="doc_author">
219 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
220 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]221</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]222
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]223<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]224<div class="doc_section"> <a name="abstract">Abstract </a></div>
225<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]226
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]227<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]228<p>This document is a reference manual for the LLVM assembly language.
229LLVM is an SSA based representation that provides type safety,
230low-level operations, flexibility, and the capability of representing
231'all' high-level languages cleanly. It is the common code
232representation used throughout all phases of the LLVM compilation
233strategy.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]234</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]235
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]236<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]237<div class="doc_section"> <a name="introduction">Introduction</a> </div>
238<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]239
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]240<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]241
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]242<p>The LLVM code representation is designed to be used in three
Gabor Greifa54634a2007-07-06 22:07:22 +0000[diff] [blame]243different forms: as an in-memory compiler IR, as an on-disk bitcode
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]244representation (suitable for fast loading by a Just-In-Time compiler),
245and as a human readable assembly language representation. This allows
246LLVM to provide a powerful intermediate representation for efficient
247compiler transformations and analysis, while providing a natural means
248to debug and visualize the transformations. The three different forms
249of LLVM are all equivalent. This document describes the human readable
250representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]251
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]252<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]253while being expressive, typed, and extensible at the same time. It
254aims to be a "universal IR" of sorts, by being at a low enough level
255that high-level ideas may be cleanly mapped to it (similar to how
256microprocessors are "universal IR's", allowing many source languages to
257be mapped to them). By providing type information, LLVM can be used as
258the target of optimizations: for example, through pointer analysis, it
259can be proven that a C automatic variable is never accessed outside of
260the current function... allowing it to be promoted to a simple SSA
261value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]262
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]263</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_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]267
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]268<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]269
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]270<p>It is important to note that this document describes 'well formed'
271LLVM assembly language. There is a difference between what the parser
272accepts and what is considered 'well formed'. For example, the
273following instruction is syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]274
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]275<div class="doc_code">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]276<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]277%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]278</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]279</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]280
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]281<p>...because the definition of <tt>%x</tt> does not dominate all of
282its uses. The LLVM infrastructure provides a verification pass that may
283be used to verify that an LLVM module is well formed. This pass is
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]284automatically run by the parser after parsing input assembly and by
Gabor Greifa54634a2007-07-06 22:07:22 +0000[diff] [blame]285the optimizer before it outputs bitcode. The violations pointed out
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]286by the verifier pass indicate bugs in transformation passes or input to
287the parser.</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]288</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]289
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]290<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]291
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]292<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]293<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]294<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]295
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]296<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]297
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]298 <p>LLVM identifiers come in two basic types: global and local. Global
299 identifiers (functions, global variables) begin with the @ character. Local
300 identifiers (register names, types) begin with the % character. Additionally,
301 there are three different formats for identifiers, for different purposes:
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]302
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]303<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]304 <li>Named values are represented as a string of characters with their prefix.
305 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
306 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]307 Identifiers which require other characters in their names can be surrounded
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]308 with quotes. In this way, anything except a <tt>&quot;</tt> character can
309 be used in a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]310
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]311 <li>Unnamed values are represented as an unsigned numeric value with their
312 prefix. For example, %12, @2, %44.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]313
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]314 <li>Constants, which are described in a <a href="#constants">section about
315 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]316</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]317
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]318<p>LLVM requires that values start with a prefix for two reasons: Compilers
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]319don't need to worry about name clashes with reserved words, and the set of
320reserved words may be expanded in the future without penalty. Additionally,
321unnamed identifiers allow a compiler to quickly come up with a temporary
322variable without having to avoid symbol table conflicts.</p>
323
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]324<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]325languages. There are keywords for different opcodes
326('<tt><a href="#i_add">add</a></tt>',
327 '<tt><a href="#i_bitcast">bitcast</a></tt>',
328 '<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]329href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]330and others. These reserved words cannot conflict with variable names, because
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]331none of them start with a prefix character ('%' or '@').</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]332
333<p>Here is an example of LLVM code to multiply the integer variable
334'<tt>%X</tt>' by 8:</p>
335
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]336<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]337
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]338<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]339<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]340%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]341</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]342</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]343
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]344<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]345
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]346<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]347<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]348%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]349</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]350</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]351
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]352<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]353
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]354<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]355<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]356<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
357<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
358%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]359</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]360</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]361
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]362<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
363important lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]364
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]365<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]366
367 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
368 line.</li>
369
370 <li>Unnamed temporaries are created when the result of a computation is not
371 assigned to a named value.</li>
372
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]373 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]374
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]375</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]376
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]377<p>...and it also shows a convention that we follow in this document. When
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]378demonstrating instructions, we will follow an instruction with a comment that
379defines the type and name of value produced. Comments are shown in italic
380text.</p>
381
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]382</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]383
384<!-- *********************************************************************** -->
385<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
386<!-- *********************************************************************** -->
387
388<!-- ======================================================================= -->
389<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
390</div>
391
392<div class="doc_text">
393
394<p>LLVM programs are composed of "Module"s, each of which is a
395translation unit of the input programs. Each module consists of
396functions, global variables, and symbol table entries. Modules may be
397combined together with the LLVM linker, which merges function (and
398global variable) definitions, resolves forward declarations, and merges
399symbol table entries. Here is an example of the "hello world" module:</p>
400
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]401<div class="doc_code">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]402<pre><i>; Declare the string constant as a global constant...</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]403<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
404 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]405
406<i>; External declaration of the puts function</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]407<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]408
409<i>; Definition of main function</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]410define i32 @main() { <i>; i32()* </i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]411 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]412 %cast210 = <a
Chris Lattner2150cde2007-06-12 17:01:15 +0000[diff] [blame]413 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]414
415 <i>; Call puts function to write out the string to stdout...</i>
416 <a
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]417 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]418 <a
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]419 href="#i_ret">ret</a> i32 0<br>}<br>
420</pre>
421</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]422
423<p>This example is made up of a <a href="#globalvars">global variable</a>
424named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
425function, and a <a href="#functionstructure">function definition</a>
426for "<tt>main</tt>".</p>
427
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]428<p>In general, a module is made up of a list of global values,
429where both functions and global variables are global values. Global values are
430represented by a pointer to a memory location (in this case, a pointer to an
431array of char, and a pointer to a function), and have one of the following <a
432href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]433
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]434</div>
435
436<!-- ======================================================================= -->
437<div class="doc_subsection">
438 <a name="linkage">Linkage Types</a>
439</div>
440
441<div class="doc_text">
442
443<p>
444All Global Variables and Functions have one of the following types of linkage:
445</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]446
447<dl>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]448
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]449 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]450
451 <dd>Global values with internal linkage are only directly accessible by
452 objects in the current module. In particular, linking code into a module with
453 an internal global value may cause the internal to be renamed as necessary to
454 avoid collisions. Because the symbol is internal to the module, all
455 references can be updated. This corresponds to the notion of the
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]456 '<tt>static</tt>' keyword in C.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]457 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]458
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]459 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]460
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]461 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
462 the same name when linkage occurs. This is typically used to implement
463 inline functions, templates, or other code which must be generated in each
464 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
465 allowed to be discarded.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]466 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]467
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]468 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]469
470 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
471 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]472 used for globals that may be emitted in multiple translation units, but that
473 are not guaranteed to be emitted into every translation unit that uses them.
474 One example of this are common globals in C, such as "<tt>int X;</tt>" at
475 global scope.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]476 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]477
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]478 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]479
480 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
481 pointer to array type. When two global variables with appending linkage are
482 linked together, the two global arrays are appended together. This is the
483 LLVM, typesafe, equivalent of having the system linker append together
484 "sections" with identical names when .o files are linked.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]485 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]486
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]487 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
488 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
489 until linked, if not linked, the symbol becomes null instead of being an
490 undefined reference.
491 </dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]492
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]493 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]494
495 <dd>If none of the above identifiers are used, the global is externally
496 visible, meaning that it participates in linkage and can be used to resolve
497 external symbol references.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]498 </dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]499</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]500
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]501 <p>
502 The next two types of linkage are targeted for Microsoft Windows platform
503 only. They are designed to support importing (exporting) symbols from (to)
504 DLLs.
505 </p>
506
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]507 <dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]508 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
509
510 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
511 or variable via a global pointer to a pointer that is set up by the DLL
512 exporting the symbol. On Microsoft Windows targets, the pointer name is
513 formed by combining <code>_imp__</code> and the function or variable name.
514 </dd>
515
516 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
517
518 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
519 pointer to a pointer in a DLL, so that it can be referenced with the
520 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
521 name is formed by combining <code>_imp__</code> and the function or variable
522 name.
523 </dd>
524
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]525</dl>
526
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]527<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]528variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
529variable and was linked with this one, one of the two would be renamed,
530preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
531external (i.e., lacking any linkage declarations), they are accessible
Reid Spencer92c671e2007-01-05 00:59:10 +0000[diff] [blame]532outside of the current module.</p>
533<p>It is illegal for a function <i>declaration</i>
534to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]535or <tt>extern_weak</tt>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]536<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
537linkages.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]538</div>
539
540<!-- ======================================================================= -->
541<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]542 <a name="callingconv">Calling Conventions</a>
543</div>
544
545<div class="doc_text">
546
547<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
548and <a href="#i_invoke">invokes</a> can all have an optional calling convention
549specified for the call. The calling convention of any pair of dynamic
550caller/callee must match, or the behavior of the program is undefined. The
551following calling conventions are supported by LLVM, and more may be added in
552the future:</p>
553
554<dl>
555 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
556
557 <dd>This calling convention (the default if no other calling convention is
558 specified) matches the target C calling conventions. This calling convention
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]559 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencer72ba4992006-12-31 21:30:18 +0000[diff] [blame]560 prototype and implemented declaration of the function (as does normal C).
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]561 </dd>
562
563 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
564
565 <dd>This calling convention attempts to make calls as fast as possible
566 (e.g. by passing things in registers). This calling convention allows the
567 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattnerc792eb32005-05-06 23:08:23 +0000[diff] [blame]568 without having to conform to an externally specified ABI. Implementations of
569 this convention should allow arbitrary tail call optimization to be supported.
570 This calling convention does not support varargs and requires the prototype of
571 all callees to exactly match the prototype of the function definition.
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]572 </dd>
573
574 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
575
576 <dd>This calling convention attempts to make code in the caller as efficient
577 as possible under the assumption that the call is not commonly executed. As
578 such, these calls often preserve all registers so that the call does not break
579 any live ranges in the caller side. This calling convention does not support
580 varargs and requires the prototype of all callees to exactly match the
581 prototype of the function definition.
582 </dd>
583
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]584 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]585
586 <dd>Any calling convention may be specified by number, allowing
587 target-specific calling conventions to be used. Target specific calling
588 conventions start at 64.
589 </dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]590</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]591
592<p>More calling conventions can be added/defined on an as-needed basis, to
593support pascal conventions or any other well-known target-independent
594convention.</p>
595
596</div>
597
598<!-- ======================================================================= -->
599<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]600 <a name="visibility">Visibility Styles</a>
601</div>
602
603<div class="doc_text">
604
605<p>
606All Global Variables and Functions have one of the following visibility styles:
607</p>
608
609<dl>
610 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
611
612 <dd>On ELF, default visibility means that the declaration is visible to other
613 modules and, in shared libraries, means that the declared entity may be
614 overridden. On Darwin, default visibility means that the declaration is
615 visible to other modules. Default visibility corresponds to "external
616 linkage" in the language.
617 </dd>
618
619 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
620
621 <dd>Two declarations of an object with hidden visibility refer to the same
622 object if they are in the same shared object. Usually, hidden visibility
623 indicates that the symbol will not be placed into the dynamic symbol table,
624 so no other module (executable or shared library) can reference it
625 directly.
626 </dd>
627
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]628 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
629
630 <dd>On ELF, protected visibility indicates that the symbol will be placed in
631 the dynamic symbol table, but that references within the defining module will
632 bind to the local symbol. That is, the symbol cannot be overridden by another
633 module.
634 </dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]635</dl>
636
637</div>
638
639<!-- ======================================================================= -->
640<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]641 <a name="globalvars">Global Variables</a>
642</div>
643
644<div class="doc_text">
645
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]646<p>Global variables define regions of memory allocated at compilation time
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]647instead of run-time. Global variables may optionally be initialized, may have
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]648an explicit section to be placed in, and may have an optional explicit alignment
649specified. A variable may be defined as "thread_local", which means that it
650will not be shared by threads (each thread will have a separated copy of the
651variable). A variable may be defined as a global "constant," which indicates
652that the contents of the variable will <b>never</b> be modified (enabling better
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]653optimization, allowing the global data to be placed in the read-only section of
654an executable, etc). Note that variables that need runtime initialization
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]655cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]656
657<p>
658LLVM explicitly allows <em>declarations</em> of global variables to be marked
659constant, even if the final definition of the global is not. This capability
660can be used to enable slightly better optimization of the program, but requires
661the language definition to guarantee that optimizations based on the
662'constantness' are valid for the translation units that do not include the
663definition.
664</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]665
666<p>As SSA values, global variables define pointer values that are in
667scope (i.e. they dominate) all basic blocks in the program. Global
668variables always define a pointer to their "content" type because they
669describe a region of memory, and all memory objects in LLVM are
670accessed through pointers.</p>
671
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]672<p>LLVM allows an explicit section to be specified for globals. If the target
673supports it, it will emit globals to the section specified.</p>
674
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]675<p>An explicit alignment may be specified for a global. If not present, or if
676the alignment is set to zero, the alignment of the global is set by the target
677to whatever it feels convenient. If an explicit alignment is specified, the
678global is forced to have at least that much alignment. All alignments must be
679a power of 2.</p>
680
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]681<p>For example, the following defines a global with an initializer, section,
682 and alignment:</p>
683
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]684<div class="doc_code">
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]685<pre>
Chris Lattner0a2d0992007-07-13 20:01:46 +0000[diff] [blame]686@G = constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]687</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]688</div>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]689
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]690</div>
691
692
693<!-- ======================================================================= -->
694<div class="doc_subsection">
695 <a name="functionstructure">Functions</a>
696</div>
697
698<div class="doc_text">
699
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]700<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
701an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]702<a href="#visibility">visibility style</a>, an optional
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]703<a href="#callingconv">calling convention</a>, a return type, an optional
704<a href="#paramattrs">parameter attribute</a> for the return type, a function
705name, a (possibly empty) argument list (each with optional
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]706<a href="#paramattrs">parameter attributes</a>), an optional section, an
707optional alignment, an opening curly brace, a list of basic blocks, and a
708closing curly brace.
709
710LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
711optional <a href="#linkage">linkage type</a>, an optional
712<a href="#visibility">visibility style</a>, an optional
713<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]714<a href="#paramattrs">parameter attribute</a> for the return type, a function
715name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]716
717<p>A function definition contains a list of basic blocks, forming the CFG for
718the function. Each basic block may optionally start with a label (giving the
719basic block a symbol table entry), contains a list of instructions, and ends
720with a <a href="#terminators">terminator</a> instruction (such as a branch or
721function return).</p>
722
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]723<p>The first basic block in a function is special in two ways: it is immediately
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]724executed on entrance to the function, and it is not allowed to have predecessor
725basic blocks (i.e. there can not be any branches to the entry block of a
726function). Because the block can have no predecessors, it also cannot have any
727<a href="#i_phi">PHI nodes</a>.</p>
728
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]729<p>LLVM allows an explicit section to be specified for functions. If the target
730supports it, it will emit functions to the section specified.</p>
731
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]732<p>An explicit alignment may be specified for a function. If not present, or if
733the alignment is set to zero, the alignment of the function is set by the target
734to whatever it feels convenient. If an explicit alignment is specified, the
735function is forced to have at least that much alignment. All alignments must be
736a power of 2.</p>
737
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]738</div>
739
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]740
741<!-- ======================================================================= -->
742<div class="doc_subsection">
743 <a name="aliasstructure">Aliases</a>
744</div>
745<div class="doc_text">
746 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikovb18f8f82007-04-28 13:45:00 +0000[diff] [blame]747 function or global variable or bitcast of global value). Aliases may have an
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]748 optional <a href="#linkage">linkage type</a>, and an
749 optional <a href="#visibility">visibility style</a>.</p>
750
751 <h5>Syntax:</h5>
752
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]753<div class="doc_code">
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]754<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]755@&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]756</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]757</div>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]758
759</div>
760
761
762
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]763<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]764<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
765<div class="doc_text">
766 <p>The return type and each parameter of a function type may have a set of
767 <i>parameter attributes</i> associated with them. Parameter attributes are
768 used to communicate additional information about the result or parameters of
769 a function. Parameter attributes are considered to be part of the function
770 type so two functions types that differ only by the parameter attributes
771 are different function types.</p>
772
Reid Spencercf7ebf52007-01-15 18:27:39 +0000[diff] [blame]773 <p>Parameter attributes are simple keywords that follow the type specified. If
774 multiple parameter attributes are needed, they are space separated. For
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]775 example:</p>
776
777<div class="doc_code">
778<pre>
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]779%someFunc = i16 (i8 signext %someParam) zeroext
780%someFunc = i16 (i8 zeroext %someParam) zeroext
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]781</pre>
782</div>
783
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]784 <p>Note that the two function types above are unique because the parameter has
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]785 a different attribute (<tt>signext</tt> in the first one, <tt>zeroext</tt> in
786 the second). Also note that the attribute for the function result
787 (<tt>zeroext</tt>) comes immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]788
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]789 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]790 <dl>
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]791 <dt><tt>zeroext</tt></dt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]792 <dd>This indicates that the parameter should be zero extended just before
793 a call to this function.</dd>
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]794 <dt><tt>signext</tt></dt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]795 <dd>This indicates that the parameter should be sign extended just before
796 a call to this function.</dd>
Anton Korobeynikove8166852007-01-28 14:30:45 +0000[diff] [blame]797 <dt><tt>inreg</tt></dt>
798 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikove93c6e82007-01-28 15:27:21 +0000[diff] [blame]799 possible) during assembling function call. Support for this attribute is
800 target-specific</dd>
Anton Korobeynikove8166852007-01-28 14:30:45 +0000[diff] [blame]801 <dt><tt>sret</tt></dt>
Anton Korobeynikove93c6e82007-01-28 15:27:21 +0000[diff] [blame]802 <dd>This indicates that the parameter specifies the address of a structure
Reid Spencer05dbb9d2007-03-22 02:02:11 +0000[diff] [blame]803 that is the return value of the function in the source program.</dd>
Zhou Sheng2444a9a2007-06-05 05:28:26 +0000[diff] [blame]804 <dt><tt>noalias</tt></dt>
805 <dd>This indicates that the parameter not alias any other object or any
806 other "noalias" objects during the function call.
Reid Spencer9d1700e2007-03-22 02:18:56 +0000[diff] [blame]807 <dt><tt>noreturn</tt></dt>
808 <dd>This function attribute indicates that the function never returns. This
809 indicates to LLVM that every call to this function should be treated as if
810 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Reid Spencer05dbb9d2007-03-22 02:02:11 +0000[diff] [blame]811 <dt><tt>nounwind</tt></dt>
812 <dd>This function attribute indicates that the function type does not use
813 the unwind instruction and does not allow stack unwinding to propagate
814 through it.</dd>
Duncan Sands27e91592007-07-27 19:57:41 +0000[diff] [blame]815 <dt><tt>nest</tt></dt>
816 <dd>This indicates that the parameter can be excised using the
817 <a href="#int_trampoline">trampoline intrinsics</a>.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]818 </dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]819
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]820</div>
821
822<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]823<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]824 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]825</div>
826
827<div class="doc_text">
828<p>
829Modules may contain "module-level inline asm" blocks, which corresponds to the
830GCC "file scope inline asm" blocks. These blocks are internally concatenated by
831LLVM and treated as a single unit, but may be separated in the .ll file if
832desired. The syntax is very simple:
833</p>
834
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]835<div class="doc_code">
836<pre>
837module asm "inline asm code goes here"
838module asm "more can go here"
839</pre>
840</div>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]841
842<p>The strings can contain any character by escaping non-printable characters.
843 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
844 for the number.
845</p>
846
847<p>
848 The inline asm code is simply printed to the machine code .s file when
849 assembly code is generated.
850</p>
851</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]852
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]853<!-- ======================================================================= -->
854<div class="doc_subsection">
855 <a name="datalayout">Data Layout</a>
856</div>
857
858<div class="doc_text">
859<p>A module may specify a target specific data layout string that specifies how
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]860data is to be laid out in memory. The syntax for the data layout is simply:</p>
861<pre> target datalayout = "<i>layout specification</i>"</pre>
862<p>The <i>layout specification</i> consists of a list of specifications
863separated by the minus sign character ('-'). Each specification starts with a
864letter and may include other information after the letter to define some
865aspect of the data layout. The specifications accepted are as follows: </p>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]866<dl>
867 <dt><tt>E</tt></dt>
868 <dd>Specifies that the target lays out data in big-endian form. That is, the
869 bits with the most significance have the lowest address location.</dd>
870 <dt><tt>e</tt></dt>
871 <dd>Specifies that hte target lays out data in little-endian form. That is,
872 the bits with the least significance have the lowest address location.</dd>
873 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
874 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
875 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
876 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
877 too.</dd>
878 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
879 <dd>This specifies the alignment for an integer type of a given bit
880 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
881 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
882 <dd>This specifies the alignment for a vector type of a given bit
883 <i>size</i>.</dd>
884 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
885 <dd>This specifies the alignment for a floating point type of a given bit
886 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
887 (double).</dd>
888 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
889 <dd>This specifies the alignment for an aggregate type of a given bit
890 <i>size</i>.</dd>
891</dl>
892<p>When constructing the data layout for a given target, LLVM starts with a
893default set of specifications which are then (possibly) overriden by the
894specifications in the <tt>datalayout</tt> keyword. The default specifications
895are given in this list:</p>
896<ul>
897 <li><tt>E</tt> - big endian</li>
898 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
899 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
900 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
901 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
902 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
903 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
904 alignment of 64-bits</li>
905 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
906 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
907 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
908 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
909 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
910</ul>
911<p>When llvm is determining the alignment for a given type, it uses the
912following rules:
913<ol>
914 <li>If the type sought is an exact match for one of the specifications, that
915 specification is used.</li>
916 <li>If no match is found, and the type sought is an integer type, then the
917 smallest integer type that is larger than the bitwidth of the sought type is
918 used. If none of the specifications are larger than the bitwidth then the the
919 largest integer type is used. For example, given the default specifications
920 above, the i7 type will use the alignment of i8 (next largest) while both
921 i65 and i256 will use the alignment of i64 (largest specified).</li>
922 <li>If no match is found, and the type sought is a vector type, then the
923 largest vector type that is smaller than the sought vector type will be used
924 as a fall back. This happens because <128 x double> can be implemented in
925 terms of 64 <2 x double>, for example.</li>
926</ol>
927</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]928
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]929<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]930<div class="doc_section"> <a name="typesystem">Type System</a> </div>
931<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]932
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]933<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]934
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]935<p>The LLVM type system is one of the most important features of the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]936intermediate representation. Being typed enables a number of
937optimizations to be performed on the IR directly, without having to do
938extra analyses on the side before the transformation. A strong type
939system makes it easier to read the generated code and enables novel
940analyses and transformations that are not feasible to perform on normal
941three address code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]942
943</div>
944
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]945<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]946<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]947<div class="doc_text">
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]948<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]949system. The current set of primitive types is as follows:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]950
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]951<table class="layout">
952 <tr class="layout">
953 <td class="left">
954 <table>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]955 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]956 <tr><th>Type</th><th>Description</th></tr>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]957 <tr><td><tt><a name="t_void">void</a></tt></td><td>No value</td></tr>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]958 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]959 </tbody>
960 </table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]961 </td>
962 <td class="right">
963 <table>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]964 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]965 <tr><th>Type</th><th>Description</th></tr>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]966 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]967 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]968 </tbody>
969 </table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]970 </td>
971 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]972</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]973</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]974
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]975<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]976<div class="doc_subsubsection"> <a name="t_classifications">Type
977Classifications</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]978<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]979<p>These different primitive types fall into a few useful
980classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]981
982<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]983 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]984 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]985 <tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]986 <td><a name="t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]987 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]988 </tr>
989 <tr>
990 <td><a name="t_floating">floating point</a></td>
991 <td><tt>float, double</tt></td>
992 </tr>
993 <tr>
994 <td><a name="t_firstclass">first class</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]995 <td><tt>i1, ..., float, double, <br/>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]996 <a href="#t_pointer">pointer</a>,<a href="#t_vector">vector</a></tt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]997 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]998 </tr>
999 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1000</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1001
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1002<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1003most important. Values of these types are the only ones which can be
1004produced by instructions, passed as arguments, or used as operands to
1005instructions. This means that all structures and arrays must be
1006manipulated either by pointer or by component.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1007</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1008
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1009<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1010<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1011
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1012<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1013
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1014<p>The real power in LLVM comes from the derived types in the system.
1015This is what allows a programmer to represent arrays, functions,
1016pointers, and other useful types. Note that these derived types may be
1017recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1018
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1019</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1020
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1021<!-- _______________________________________________________________________ -->
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1022<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1023
1024<div class="doc_text">
1025
1026<h5>Overview:</h5>
1027<p>The integer type is a very simple derived type that simply specifies an
1028arbitrary bit width for the integer type desired. Any bit width from 1 bit to
10292^23-1 (about 8 million) can be specified.</p>
1030
1031<h5>Syntax:</h5>
1032
1033<pre>
1034 iN
1035</pre>
1036
1037<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1038value.</p>
1039
1040<h5>Examples:</h5>
1041<table class="layout">
1042 <tr class="layout">
1043 <td class="left">
1044 <tt>i1</tt><br/>
1045 <tt>i4</tt><br/>
1046 <tt>i8</tt><br/>
1047 <tt>i16</tt><br/>
1048 <tt>i32</tt><br/>
1049 <tt>i42</tt><br/>
1050 <tt>i64</tt><br/>
1051 <tt>i1942652</tt><br/>
1052 </td>
1053 <td class="left">
1054 A boolean integer of 1 bit<br/>
1055 A nibble sized integer of 4 bits.<br/>
1056 A byte sized integer of 8 bits.<br/>
1057 A half word sized integer of 16 bits.<br/>
1058 A word sized integer of 32 bits.<br/>
1059 An integer whose bit width is the answer. <br/>
1060 A double word sized integer of 64 bits.<br/>
1061 A really big integer of over 1 million bits.<br/>
1062 </td>
1063 </tr>
1064</table>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1065</div>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1066
1067<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1068<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1069
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1070<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1071
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1072<h5>Overview:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1073
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1074<p>The array type is a very simple derived type that arranges elements
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1075sequentially in memory. The array type requires a size (number of
1076elements) and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1077
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1078<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1079
1080<pre>
1081 [&lt;# elements&gt; x &lt;elementtype&gt;]
1082</pre>
1083
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1084<p>The number of elements is a constant integer value; elementtype may
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1085be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1086
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1087<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1088<table class="layout">
1089 <tr class="layout">
1090 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1091 <tt>[40 x i32 ]</tt><br/>
1092 <tt>[41 x i32 ]</tt><br/>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1093 <tt>[40 x i8]</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1094 </td>
1095 <td class="left">
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1096 Array of 40 32-bit integer values.<br/>
1097 Array of 41 32-bit integer values.<br/>
1098 Array of 40 8-bit integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1099 </td>
1100 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1101</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1102<p>Here are some examples of multidimensional arrays:</p>
1103<table class="layout">
1104 <tr class="layout">
1105 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1106 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1107 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1108 <tt>[2 x [3 x [4 x i16]]]</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1109 </td>
1110 <td class="left">
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1111 3x4 array of 32-bit integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1112 12x10 array of single precision floating point values.<br/>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1113 2x3x4 array of 16-bit integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1114 </td>
1115 </tr>
1116</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1117
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1118<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1119length array. Normally, accesses past the end of an array are undefined in
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1120LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1121As a special case, however, zero length arrays are recognized to be variable
1122length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1123type "{ i32, [0 x float]}", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1124
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1125</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1126
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1127<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1128<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1129<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1130<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1131<p>The function type can be thought of as a function signature. It
1132consists of a return type and a list of formal parameter types.
John Criswella0d50d22003-11-25 21:45:46 +0000[diff] [blame]1133Function types are usually used to build virtual function tables
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1134(which are structures of pointers to functions), for indirect function
1135calls, and when defining a function.</p>
John Criswella0d50d22003-11-25 21:45:46 +0000[diff] [blame]1136<p>
1137The return type of a function type cannot be an aggregate type.
1138</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1139<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1140<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1141<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]1142specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1143which indicates that the function takes a variable number of arguments.
1144Variable argument functions can access their arguments with the <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1145 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1146<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1147<table class="layout">
1148 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1149 <td class="left"><tt>i32 (i32)</tt></td>
1150 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1151 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1152 </tr><tr class="layout">
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]1153 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1154 </tt></td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1155 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1156 an <tt>i16</tt> that should be sign extended and a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1157 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1158 <tt>float</tt>.
1159 </td>
1160 </tr><tr class="layout">
1161 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1162 <td class="left">A vararg function that takes at least one
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1163 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1164 which returns an integer. This is the signature for <tt>printf</tt> in
1165 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1166 </td>
1167 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1168</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1169
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1170</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1171<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1172<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1173<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1174<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1175<p>The structure type is used to represent a collection of data members
1176together in memory. The packing of the field types is defined to match
1177the ABI of the underlying processor. The elements of a structure may
1178be any type that has a size.</p>
1179<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1180and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1181field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1182instruction.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1183<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1184<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1185<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1186<table class="layout">
1187 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1188 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1189 <td class="left">A triple of three <tt>i32</tt> values</td>
1190 </tr><tr class="layout">
1191 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1192 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1193 second element is a <a href="#t_pointer">pointer</a> to a
1194 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1195 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1196 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1197</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1198</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1199
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1200<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1201<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1202</div>
1203<div class="doc_text">
1204<h5>Overview:</h5>
1205<p>The packed structure type is used to represent a collection of data members
1206together in memory. There is no padding between fields. Further, the alignment
1207of a packed structure is 1 byte. The elements of a packed structure may
1208be any type that has a size.</p>
1209<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1210and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1211field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1212instruction.</p>
1213<h5>Syntax:</h5>
1214<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1215<h5>Examples:</h5>
1216<table class="layout">
1217 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1218 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1219 <td class="left">A triple of three <tt>i32</tt> values</td>
1220 </tr><tr class="layout">
1221 <td class="left"><tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}&nbsp;&gt;</tt></td>
1222 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1223 second element is a <a href="#t_pointer">pointer</a> to a
1224 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1225 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1226 </tr>
1227</table>
1228</div>
1229
1230<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1231<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1232<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1233<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1234<p>As in many languages, the pointer type represents a pointer or
1235reference to another object, which must live in memory.</p>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1236<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1237<pre> &lt;type&gt; *<br></pre>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1238<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1239<table class="layout">
1240 <tr class="layout">
1241 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1242 <tt>[4x i32]*</tt><br/>
1243 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1244 </td>
1245 <td class="left">
1246 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]1247 four <tt>i32</tt> values<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1248 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1249 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1250 <tt>i32</tt>.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1251 </td>
1252 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1253</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1254</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1255
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1256<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1257<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1258<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1259
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1260<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1261
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1262<p>A vector type is a simple derived type that represents a vector
1263of elements. Vector types are used when multiple primitive data
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1264are operated in parallel using a single instruction (SIMD).
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1265A vector type requires a size (number of
Chris Lattner330ce692005-11-10 01:44:22 +0000[diff] [blame]1266elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1267of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1268considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1269
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1270<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1271
1272<pre>
1273 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1274</pre>
1275
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1276<p>The number of elements is a constant integer value; elementtype may
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1277be any integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1278
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1279<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1280
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1281<table class="layout">
1282 <tr class="layout">
1283 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1284 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1285 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1286 <tt>&lt;2 x i64&gt;</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1287 </td>
1288 <td class="left">
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1289 Vector of 4 32-bit integer values.<br/>
1290 Vector of 8 floating-point values.<br/>
1291 Vector of 2 64-bit integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1292 </td>
1293 </tr>
1294</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1295</div>
1296
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1297<!-- _______________________________________________________________________ -->
1298<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1299<div class="doc_text">
1300
1301<h5>Overview:</h5>
1302
1303<p>Opaque types are used to represent unknown types in the system. This
1304corresponds (for example) to the C notion of a foward declared structure type.
1305In LLVM, opaque types can eventually be resolved to any type (not just a
1306structure type).</p>
1307
1308<h5>Syntax:</h5>
1309
1310<pre>
1311 opaque
1312</pre>
1313
1314<h5>Examples:</h5>
1315
1316<table class="layout">
1317 <tr class="layout">
1318 <td class="left">
1319 <tt>opaque</tt>
1320 </td>
1321 <td class="left">
1322 An opaque type.<br/>
1323 </td>
1324 </tr>
1325</table>
1326</div>
1327
1328
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1329<!-- *********************************************************************** -->
1330<div class="doc_section"> <a name="constants">Constants</a> </div>
1331<!-- *********************************************************************** -->
1332
1333<div class="doc_text">
1334
1335<p>LLVM has several different basic types of constants. This section describes
1336them all and their syntax.</p>
1337
1338</div>
1339
1340<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1341<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1342
1343<div class="doc_text">
1344
1345<dl>
1346 <dt><b>Boolean constants</b></dt>
1347
1348 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1349 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1350 </dd>
1351
1352 <dt><b>Integer constants</b></dt>
1353
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1354 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1355 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1356 integer types.
1357 </dd>
1358
1359 <dt><b>Floating point constants</b></dt>
1360
1361 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1362 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1363 notation (see below). Floating point constants must have a <a
1364 href="#t_floating">floating point</a> type. </dd>
1365
1366 <dt><b>Null pointer constants</b></dt>
1367
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1368 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1369 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1370
1371</dl>
1372
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1373<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1374of floating point constants. For example, the form '<tt>double
13750x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
13764.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1377(and the only time that they are generated by the disassembler) is when a
1378floating point constant must be emitted but it cannot be represented as a
1379decimal floating point number. For example, NaN's, infinities, and other
1380special values are represented in their IEEE hexadecimal format so that
1381assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1382
1383</div>
1384
1385<!-- ======================================================================= -->
1386<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1387</div>
1388
1389<div class="doc_text">
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]1390<p>Aggregate constants arise from aggregation of simple constants
1391and smaller aggregate constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1392
1393<dl>
1394 <dt><b>Structure constants</b></dt>
1395
1396 <dd>Structure constants are represented with notation similar to structure
1397 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1398 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
Chris Lattner0a2d0992007-07-13 20:01:46 +0000[diff] [blame]1399 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]1400 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1401 types of elements must match those specified by the type.
1402 </dd>
1403
1404 <dt><b>Array constants</b></dt>
1405
1406 <dd>Array constants are represented with notation similar to array type
1407 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1408 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1409 constants must have <a href="#t_array">array type</a>, and the number and
1410 types of elements must match those specified by the type.
1411 </dd>
1412
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1413 <dt><b>Vector constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1414
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1415 <dd>Vector constants are represented with notation similar to vector type
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1416 definitions (a comma separated list of elements, surrounded by
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1417 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1418 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1419 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1420 match those specified by the type.
1421 </dd>
1422
1423 <dt><b>Zero initialization</b></dt>
1424
1425 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1426 value to zero of <em>any</em> type, including scalar and aggregate types.
1427 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]1428 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1429 initializers.
1430 </dd>
1431</dl>
1432
1433</div>
1434
1435<!-- ======================================================================= -->
1436<div class="doc_subsection">
1437 <a name="globalconstants">Global Variable and Function Addresses</a>
1438</div>
1439
1440<div class="doc_text">
1441
1442<p>The addresses of <a href="#globalvars">global variables</a> and <a
1443href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1444constants. These constants are explicitly referenced when the <a
1445href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1446href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1447file:</p>
1448
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1449<div class="doc_code">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1450<pre>
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]1451@X = global i32 17
1452@Y = global i32 42
1453@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1454</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1455</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1456
1457</div>
1458
1459<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1460<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1461<div class="doc_text">
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1462 <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]1463 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1464 a constant is permitted.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1465
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1466 <p>Undefined values indicate to the compiler that the program is well defined
1467 no matter what value is used, giving the compiler more freedom to optimize.
1468 </p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1469</div>
1470
1471<!-- ======================================================================= -->
1472<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1473</div>
1474
1475<div class="doc_text">
1476
1477<p>Constant expressions are used to allow expressions involving other constants
1478to be used as constants. Constant expressions may be of any <a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1479href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1480that does not have side effects (e.g. load and call are not supported). The
1481following is the syntax for constant expressions:</p>
1482
1483<dl>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1484 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1485 <dd>Truncate a constant to another type. The bit size of CST must be larger
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1486 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1487
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1488 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1489 <dd>Zero extend a constant to another type. The bit size of CST must be
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1490 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1491
1492 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1493 <dd>Sign extend a constant to another type. The bit size of CST must be
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1494 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1495
1496 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1497 <dd>Truncate a floating point constant to another floating point type. The
1498 size of CST must be larger than the size of TYPE. Both types must be
1499 floating point.</dd>
1500
1501 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1502 <dd>Floating point extend a constant to another type. The size of CST must be
1503 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1504
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]1505 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1506 <dd>Convert a floating point constant to the corresponding unsigned integer
1507 constant. TYPE must be an integer type. CST must be floating point. If the
1508 value won't fit in the integer type, the results are undefined.</dd>
1509
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1510 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1511 <dd>Convert a floating point constant to the corresponding signed integer
1512 constant. TYPE must be an integer type. CST must be floating point. If the
1513 value won't fit in the integer type, the results are undefined.</dd>
1514
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1515 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1516 <dd>Convert an unsigned integer constant to the corresponding floating point
1517 constant. TYPE must be floating point. CST must be of integer type. If the
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]1518 value won't fit in the floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1519
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1520 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1521 <dd>Convert a signed integer constant to the corresponding floating point
1522 constant. TYPE must be floating point. CST must be of integer type. If the
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]1523 value won't fit in the floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1524
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1525 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1526 <dd>Convert a pointer typed constant to the corresponding integer constant
1527 TYPE must be an integer type. CST must be of pointer type. The CST value is
1528 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1529
1530 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1531 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1532 pointer type. CST must be of integer type. The CST value is zero extended,
1533 truncated, or unchanged to make it fit in a pointer size. This one is
1534 <i>really</i> dangerous!</dd>
1535
1536 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1537 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1538 identical (same number of bits). The conversion is done as if the CST value
1539 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]1540 with this operator, just the type. This can be used for conversion of
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1541 vector types to any other type, as long as they have the same bit width. For
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1542 pointers it is only valid to cast to another pointer type.
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1543 </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1544
1545 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1546
1547 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1548 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1549 instruction, the index list may have zero or more indexes, which are required
1550 to make sense for the type of "CSTPTR".</dd>
1551
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1552 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1553
1554 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1555 constants.</dd>
1556
1557 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1558 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1559
1560 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1561 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1562
1563 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1564
1565 <dd>Perform the <a href="#i_extractelement">extractelement
1566 operation</a> on constants.
1567
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1568 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1569
1570 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1571 operation</a> on constants.</dd>
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1572
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1573
1574 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1575
1576 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1577 operation</a> on constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1578
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1579 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1580
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1581 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1582 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1583 binary</a> operations. The constraints on operands are the same as those for
1584 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1585 values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1586</dl>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1587</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]1588
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1589<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1590<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1591<!-- *********************************************************************** -->
1592
1593<!-- ======================================================================= -->
1594<div class="doc_subsection">
1595<a name="inlineasm">Inline Assembler Expressions</a>
1596</div>
1597
1598<div class="doc_text">
1599
1600<p>
1601LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1602Module-Level Inline Assembly</a>) through the use of a special value. This
1603value represents the inline assembler as a string (containing the instructions
1604to emit), a list of operand constraints (stored as a string), and a flag that
1605indicates whether or not the inline asm expression has side effects. An example
1606inline assembler expression is:
1607</p>
1608
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1609<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1610<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1611i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1612</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1613</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1614
1615<p>
1616Inline assembler expressions may <b>only</b> be used as the callee operand of
1617a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1618</p>
1619
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1620<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1621<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1622%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1623</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1624</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1625
1626<p>
1627Inline asms with side effects not visible in the constraint list must be marked
1628as having side effects. This is done through the use of the
1629'<tt>sideeffect</tt>' keyword, like so:
1630</p>
1631
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1632<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1633<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1634call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1635</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1636</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1637
1638<p>TODO: The format of the asm and constraints string still need to be
1639documented here. Constraints on what can be done (e.g. duplication, moving, etc
1640need to be documented).
1641</p>
1642
1643</div>
1644
1645<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1646<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1647<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1648
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1649<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1650
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1651<p>The LLVM instruction set consists of several different
1652classifications of instructions: <a href="#terminators">terminator
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1653instructions</a>, <a href="#binaryops">binary instructions</a>,
1654<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1655 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1656instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1657
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1658</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1659
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1660<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1661<div class="doc_subsection"> <a name="terminators">Terminator
1662Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1663
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1664<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1665
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1666<p>As mentioned <a href="#functionstructure">previously</a>, every
1667basic block in a program ends with a "Terminator" instruction, which
1668indicates which block should be executed after the current block is
1669finished. These terminator instructions typically yield a '<tt>void</tt>'
1670value: they produce control flow, not values (the one exception being
1671the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1672<p>There are six different terminator instructions: the '<a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1673 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1674instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1675the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1676 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1677 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1678
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1679</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1680
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1681<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1682<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1683Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1684<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1685<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1686<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]1687 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1688</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1689<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1690<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1691value) from a function back to the caller.</p>
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]1692<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1693returns a value and then causes control flow, and one that just causes
1694control flow to occur.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1695<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1696<p>The '<tt>ret</tt>' instruction may return any '<a
1697 href="#t_firstclass">first class</a>' type. Notice that a function is
1698not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1699instruction inside of the function that returns a value that does not
1700match the return type of the function.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1701<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1702<p>When the '<tt>ret</tt>' instruction is executed, control flow
1703returns back to the calling function's context. If the caller is a "<a
John Criswell40db33f2004-06-25 15:16:57 +0000[diff] [blame]1704 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1705the instruction after the call. If the caller was an "<a
1706 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1707at the beginning of the "normal" destination block. If the instruction
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1708returns a value, that value shall set the call or invoke instruction's
1709return value.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1710<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1711<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1712 ret void <i>; Return from a void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1713</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1714</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1715<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1716<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1717<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1718<h5>Syntax:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1719<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1720</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1721<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1722<p>The '<tt>br</tt>' instruction is used to cause control flow to
1723transfer to a different basic block in the current function. There are
1724two forms of this instruction, corresponding to a conditional branch
1725and an unconditional branch.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1726<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1727<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1728single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1729unconditional form of the '<tt>br</tt>' instruction takes a single
1730'<tt>label</tt>' value as a target.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1731<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1732<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1733argument is evaluated. If the value is <tt>true</tt>, control flows
1734to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1735control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1736<h5>Example:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1737<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq, i32 %a, %b<br> br i1 %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1738 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]1739</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1740<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1741<div class="doc_subsubsection">
1742 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1743</div>
1744
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1745<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1746<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1747
1748<pre>
1749 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1750</pre>
1751
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1752<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1753
1754<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1755several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1756instruction, allowing a branch to occur to one of many possible
1757destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1758
1759
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1760<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1761
1762<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1763comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1764an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1765table is not allowed to contain duplicate constant entries.</p>
1766
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1767<h5>Semantics:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1768
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1769<p>The <tt>switch</tt> instruction specifies a table of values and
1770destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1771table is searched for the given value. If the value is found, control flow is
1772transfered to the corresponding destination; otherwise, control flow is
1773transfered to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1774
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1775<h5>Implementation:</h5>
1776
1777<p>Depending on properties of the target machine and the particular
1778<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1779ways. For example, it could be generated as a series of chained conditional
1780branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1781
1782<h5>Example:</h5>
1783
1784<pre>
1785 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1786 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1787 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1788
1789 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1790 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1791
1792 <i>; Implement a jump table:</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1793 switch i32 %val, label %otherwise [ i32 0, label %onzero
1794 i32 1, label %onone
1795 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1796</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1797</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1798
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1799<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1800<div class="doc_subsubsection">
1801 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1802</div>
1803
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1804<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1805
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1806<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1807
1808<pre>
1809 &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]1810 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1811</pre>
1812
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]1813<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1814
1815<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1816function, with the possibility of control flow transfer to either the
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1817'<tt>normal</tt>' label or the
1818'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1819"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1820"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1821href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1822continued at the dynamically nearest "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1823
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1824<h5>Arguments:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1825
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1826<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1827
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1828<ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1829 <li>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]1830 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1831 convention</a> the call should use. If none is specified, the call defaults
1832 to using C calling conventions.
1833 </li>
1834 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1835 function value being invoked. In most cases, this is a direct function
1836 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1837 an arbitrary pointer to function value.
1838 </li>
1839
1840 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1841 function to be invoked. </li>
1842
1843 <li>'<tt>function args</tt>': argument list whose types match the function
1844 signature argument types. If the function signature indicates the function
1845 accepts a variable number of arguments, the extra arguments can be
1846 specified. </li>
1847
1848 <li>'<tt>normal label</tt>': the label reached when the called function
1849 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1850
1851 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1852 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1853
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1854</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1855
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1856<h5>Semantics:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1857
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1858<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1859href="#i_call">call</a></tt>' instruction in most regards. The primary
1860difference is that it establishes an association with a label, which is used by
1861the runtime library to unwind the stack.</p>
1862
1863<p>This instruction is used in languages with destructors to ensure that proper
1864cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1865exception. Additionally, this is important for implementation of
1866'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1867
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1868<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1869<pre>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1870 %retval = invoke i32 %Test(i32 15) to label %Continue
1871 unwind label %TestCleanup <i>; {i32}:retval set</i>
1872 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1873 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1874</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1875</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1876
1877
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1878<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1879
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1880<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1881Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1882
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1883<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1884
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1885<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1886<pre>
1887 unwind
1888</pre>
1889
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1890<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1891
1892<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1893at the first callee in the dynamic call stack which used an <a
1894href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1895primarily used to implement exception handling.</p>
1896
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1897<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1898
1899<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1900immediately halt. The dynamic call stack is then searched for the first <a
1901href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1902execution continues at the "exceptional" destination block specified by the
1903<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1904dynamic call chain, undefined behavior results.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1905</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1906
1907<!-- _______________________________________________________________________ -->
1908
1909<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1910Instruction</a> </div>
1911
1912<div class="doc_text">
1913
1914<h5>Syntax:</h5>
1915<pre>
1916 unreachable
1917</pre>
1918
1919<h5>Overview:</h5>
1920
1921<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1922instruction is used to inform the optimizer that a particular portion of the
1923code is not reachable. This can be used to indicate that the code after a
1924no-return function cannot be reached, and other facts.</p>
1925
1926<h5>Semantics:</h5>
1927
1928<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1929</div>
1930
1931
1932
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1933<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1934<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1935<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1936<p>Binary operators are used to do most of the computation in a
1937program. They require two operands, execute an operation on them, and
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1938produce a single value. The operands might represent
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1939multiple data, as is the case with the <a href="#t_vector">vector</a> data type.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1940The result value of a binary operator is not
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1941necessarily the same type as its operands.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1942<p>There are several different binary operators:</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1943</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1944<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1945<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1946Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1947<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1948<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1949<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]1950</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1951<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1952<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1953<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1954<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1955 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1956 This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1957Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1958<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1959<p>The value produced is the integer or floating point sum of the two
1960operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1961<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1962<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]1963</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1964</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1965<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1966<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1967Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1968<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1969<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1970<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]1971</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1972<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1973<p>The '<tt>sub</tt>' instruction returns the difference of its two
1974operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1975<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1976instruction present in most other intermediate representations.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1977<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1978<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1979 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1980values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1981This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1982Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1983<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1984<p>The value produced is the integer or floating point difference of
1985the two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1986<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]1987<pre>
1988 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1989 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1990</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1991</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1992<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1993<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1994Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1995<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1996<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1997<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]1998</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1999<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2000<p>The '<tt>mul</tt>' instruction returns the product of its two
2001operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2002<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2003<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2004 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2005values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2006This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2007Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2008<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2009<p>The value produced is the integer or floating point product of the
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2010two operands.</p>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]2011<p>Because the operands are the same width, the result of an integer
2012multiplication is the same whether the operands should be deemed unsigned or
2013signed.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2014<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2015<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]2016</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2017</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2018<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2019<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2020</a></div>
2021<div class="doc_text">
2022<h5>Syntax:</h5>
2023<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2024</pre>
2025<h5>Overview:</h5>
2026<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2027operands.</p>
2028<h5>Arguments:</h5>
2029<p>The two arguments to the '<tt>udiv</tt>' instruction must be
2030<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2031types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2032of the values in which case the elements must be integers.</p>
2033<h5>Semantics:</h5>
2034<p>The value produced is the unsigned integer quotient of the two operands. This
2035instruction always performs an unsigned division operation, regardless of
2036whether the arguments are unsigned or not.</p>
2037<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2038<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]2039</pre>
2040</div>
2041<!-- _______________________________________________________________________ -->
2042<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2043</a> </div>
2044<div class="doc_text">
2045<h5>Syntax:</h5>
2046<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2047</pre>
2048<h5>Overview:</h5>
2049<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2050operands.</p>
2051<h5>Arguments:</h5>
2052<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2053<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2054types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2055of the values in which case the elements must be integers.</p>
2056<h5>Semantics:</h5>
2057<p>The value produced is the signed integer quotient of the two operands. This
2058instruction always performs a signed division operation, regardless of whether
2059the arguments are signed or not.</p>
2060<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2061<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]2062</pre>
2063</div>
2064<!-- _______________________________________________________________________ -->
2065<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2066Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2067<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2068<h5>Syntax:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2069<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]2070</pre>
2071<h5>Overview:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2072<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2073operands.</p>
2074<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2075<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2076<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2077identical types. This instruction can also take <a href="#t_vector">vector</a>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2078versions of floating point values.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2079<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2080<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2081<h5>Example:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2082<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]2083</pre>
2084</div>
2085<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2086<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2087</div>
2088<div class="doc_text">
2089<h5>Syntax:</h5>
2090<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2091</pre>
2092<h5>Overview:</h5>
2093<p>The '<tt>urem</tt>' instruction returns the remainder from the
2094unsigned division of its two arguments.</p>
2095<h5>Arguments:</h5>
2096<p>The two arguments to the '<tt>urem</tt>' instruction must be
2097<a href="#t_integer">integer</a> values. Both arguments must have identical
2098types.</p>
2099<h5>Semantics:</h5>
2100<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
2101This instruction always performs an unsigned division to get the remainder,
2102regardless of whether the arguments are unsigned or not.</p>
2103<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2104<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]2105</pre>
2106
2107</div>
2108<!-- _______________________________________________________________________ -->
2109<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2110Instruction</a> </div>
2111<div class="doc_text">
2112<h5>Syntax:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2113<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]2114</pre>
2115<h5>Overview:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2116<p>The '<tt>srem</tt>' instruction returns the remainder from the
2117signed division of its two operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2118<h5>Arguments:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2119<p>The two arguments to the '<tt>srem</tt>' instruction must be
2120<a href="#t_integer">integer</a> values. Both arguments must have identical
2121types.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2122<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2123<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2124has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2125operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2126a value. For more information about the difference, see <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2127 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2128Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencerdb3b93b2007-03-24 22:40:44 +0000[diff] [blame]2129please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2130Wikipedia: modulo operation</a>.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2131<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2132<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]2133</pre>
2134
2135</div>
2136<!-- _______________________________________________________________________ -->
2137<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2138Instruction</a> </div>
2139<div class="doc_text">
2140<h5>Syntax:</h5>
2141<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2142</pre>
2143<h5>Overview:</h5>
2144<p>The '<tt>frem</tt>' instruction returns the remainder from the
2145division of its two operands.</p>
2146<h5>Arguments:</h5>
2147<p>The two arguments to the '<tt>frem</tt>' instruction must be
2148<a href="#t_floating">floating point</a> values. Both arguments must have
2149identical types.</p>
2150<h5>Semantics:</h5>
2151<p>This instruction returns the <i>remainder</i> of a division.</p>
2152<h5>Example:</h5>
2153<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]2154</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2155</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]2156
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2157<!-- ======================================================================= -->
2158<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2159Operations</a> </div>
2160<div class="doc_text">
2161<p>Bitwise binary operators are used to do various forms of
2162bit-twiddling in a program. They are generally very efficient
2163instructions and can commonly be strength reduced from other
2164instructions. They require two operands, execute an operation on them,
2165and produce a single value. The resulting value of the bitwise binary
2166operators is always the same type as its first operand.</p>
2167</div>
2168
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2169<!-- _______________________________________________________________________ -->
2170<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2171Instruction</a> </div>
2172<div class="doc_text">
2173<h5>Syntax:</h5>
2174<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2175</pre>
2176<h5>Overview:</h5>
2177<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2178the left a specified number of bits.</p>
2179<h5>Arguments:</h5>
2180<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2181 href="#t_integer">integer</a> type.</p>
2182<h5>Semantics:</h5>
2183<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
2184<h5>Example:</h5><pre>
2185 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2186 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2187 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
2188</pre>
2189</div>
2190<!-- _______________________________________________________________________ -->
2191<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2192Instruction</a> </div>
2193<div class="doc_text">
2194<h5>Syntax:</h5>
2195<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2196</pre>
2197
2198<h5>Overview:</h5>
2199<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2200operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2201
2202<h5>Arguments:</h5>
2203<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2204<a href="#t_integer">integer</a> type.</p>
2205
2206<h5>Semantics:</h5>
2207<p>This instruction always performs a logical shift right operation. The most
2208significant bits of the result will be filled with zero bits after the
2209shift.</p>
2210
2211<h5>Example:</h5>
2212<pre>
2213 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2214 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2215 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2216 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
2217</pre>
2218</div>
2219
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2220<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2221<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2222Instruction</a> </div>
2223<div class="doc_text">
2224
2225<h5>Syntax:</h5>
2226<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2227</pre>
2228
2229<h5>Overview:</h5>
2230<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2231operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2232
2233<h5>Arguments:</h5>
2234<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2235<a href="#t_integer">integer</a> type.</p>
2236
2237<h5>Semantics:</h5>
2238<p>This instruction always performs an arithmetic shift right operation,
2239The most significant bits of the result will be filled with the sign bit
2240of <tt>var1</tt>.</p>
2241
2242<h5>Example:</h5>
2243<pre>
2244 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2245 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2246 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2247 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
2248</pre>
2249</div>
2250
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2251<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2252<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2253Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2254<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2255<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2256<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]2257</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2258<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2259<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2260its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2261<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2262<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2263 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2264identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2265<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2266<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2267<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2268<div style="align: center">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2269<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2270 <tbody>
2271 <tr>
2272 <td>In0</td>
2273 <td>In1</td>
2274 <td>Out</td>
2275 </tr>
2276 <tr>
2277 <td>0</td>
2278 <td>0</td>
2279 <td>0</td>
2280 </tr>
2281 <tr>
2282 <td>0</td>
2283 <td>1</td>
2284 <td>0</td>
2285 </tr>
2286 <tr>
2287 <td>1</td>
2288 <td>0</td>
2289 <td>0</td>
2290 </tr>
2291 <tr>
2292 <td>1</td>
2293 <td>1</td>
2294 <td>1</td>
2295 </tr>
2296 </tbody>
2297</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2298</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2299<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2300<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2301 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2302 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2303</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2304</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2305<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2306<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2307<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2308<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2309<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]2310</pre>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2311<h5>Overview:</h5>
2312<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2313or of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2314<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2315<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2316 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2317identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2318<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2319<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2320<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2321<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2322<table border="1" cellspacing="0" cellpadding="4">
2323 <tbody>
2324 <tr>
2325 <td>In0</td>
2326 <td>In1</td>
2327 <td>Out</td>
2328 </tr>
2329 <tr>
2330 <td>0</td>
2331 <td>0</td>
2332 <td>0</td>
2333 </tr>
2334 <tr>
2335 <td>0</td>
2336 <td>1</td>
2337 <td>1</td>
2338 </tr>
2339 <tr>
2340 <td>1</td>
2341 <td>0</td>
2342 <td>1</td>
2343 </tr>
2344 <tr>
2345 <td>1</td>
2346 <td>1</td>
2347 <td>1</td>
2348 </tr>
2349 </tbody>
2350</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2351</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2352<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2353<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2354 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2355 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2356</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2357</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2358<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2359<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2360Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2361<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2362<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2363<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]2364</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2365<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2366<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2367or of its two operands. The <tt>xor</tt> is used to implement the
2368"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2369<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2370<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2371 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2372identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2373<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2374<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2375<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2376<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2377<table border="1" cellspacing="0" cellpadding="4">
2378 <tbody>
2379 <tr>
2380 <td>In0</td>
2381 <td>In1</td>
2382 <td>Out</td>
2383 </tr>
2384 <tr>
2385 <td>0</td>
2386 <td>0</td>
2387 <td>0</td>
2388 </tr>
2389 <tr>
2390 <td>0</td>
2391 <td>1</td>
2392 <td>1</td>
2393 </tr>
2394 <tr>
2395 <td>1</td>
2396 <td>0</td>
2397 <td>1</td>
2398 </tr>
2399 <tr>
2400 <td>1</td>
2401 <td>1</td>
2402 <td>0</td>
2403 </tr>
2404 </tbody>
2405</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2406</div>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2407<p> </p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2408<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2409<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2410 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2411 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2412 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2413</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2414</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2415
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2416<!-- ======================================================================= -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2417<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2418 <a name="vectorops">Vector Operations</a>
2419</div>
2420
2421<div class="doc_text">
2422
2423<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2424target-independent manner. These instructions cover the element-access and
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2425vector-specific operations needed to process vectors effectively. While LLVM
2426does directly support these vector operations, many sophisticated algorithms
2427will want to use target-specific intrinsics to take full advantage of a specific
2428target.</p>
2429
2430</div>
2431
2432<!-- _______________________________________________________________________ -->
2433<div class="doc_subsubsection">
2434 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2435</div>
2436
2437<div class="doc_text">
2438
2439<h5>Syntax:</h5>
2440
2441<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2442 &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]2443</pre>
2444
2445<h5>Overview:</h5>
2446
2447<p>
2448The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2449element from a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2450</p>
2451
2452
2453<h5>Arguments:</h5>
2454
2455<p>
2456The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2457value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2458an index indicating the position from which to extract the element.
2459The index may be a variable.</p>
2460
2461<h5>Semantics:</h5>
2462
2463<p>
2464The result is a scalar of the same type as the element type of
2465<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2466<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2467results are undefined.
2468</p>
2469
2470<h5>Example:</h5>
2471
2472<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2473 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2474</pre>
2475</div>
2476
2477
2478<!-- _______________________________________________________________________ -->
2479<div class="doc_subsubsection">
2480 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2481</div>
2482
2483<div class="doc_text">
2484
2485<h5>Syntax:</h5>
2486
2487<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2488 &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]2489</pre>
2490
2491<h5>Overview:</h5>
2492
2493<p>
2494The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2495element into a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2496</p>
2497
2498
2499<h5>Arguments:</h5>
2500
2501<p>
2502The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2503value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2504scalar value whose type must equal the element type of the first
2505operand. The third operand is an index indicating the position at
2506which to insert the value. The index may be a variable.</p>
2507
2508<h5>Semantics:</h5>
2509
2510<p>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2511The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2512element values are those of <tt>val</tt> except at position
2513<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2514exceeds the length of <tt>val</tt>, the results are undefined.
2515</p>
2516
2517<h5>Example:</h5>
2518
2519<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2520 %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]2521</pre>
2522</div>
2523
2524<!-- _______________________________________________________________________ -->
2525<div class="doc_subsubsection">
2526 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2527</div>
2528
2529<div class="doc_text">
2530
2531<h5>Syntax:</h5>
2532
2533<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2534 &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]2535</pre>
2536
2537<h5>Overview:</h5>
2538
2539<p>
2540The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2541from two input vectors, returning a vector of the same type.
2542</p>
2543
2544<h5>Arguments:</h5>
2545
2546<p>
2547The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2548with types that match each other and types that match the result of the
2549instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2550of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2551</p>
2552
2553<p>
2554The shuffle mask operand is required to be a constant vector with either
2555constant integer or undef values.
2556</p>
2557
2558<h5>Semantics:</h5>
2559
2560<p>
2561The elements of the two input vectors are numbered from left to right across
2562both of the vectors. The shuffle mask operand specifies, for each element of
2563the result vector, which element of the two input registers the result element
2564gets. The element selector may be undef (meaning "don't care") and the second
2565operand may be undef if performing a shuffle from only one vector.
2566</p>
2567
2568<h5>Example:</h5>
2569
2570<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2571 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2572 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2573 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2574 &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]2575</pre>
2576</div>
2577
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]2578
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2579<!-- ======================================================================= -->
2580<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]2581 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2582</div>
2583
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2584<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2585
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2586<p>A key design point of an SSA-based representation is how it
2587represents memory. In LLVM, no memory locations are in SSA form, which
2588makes things very simple. This section describes how to read, write,
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2589allocate, and free memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2590
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2591</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2592
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2593<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2594<div class="doc_subsubsection">
2595 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2596</div>
2597
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2598<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2599
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2600<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2601
2602<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2603 &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]2604</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2605
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2606<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2607
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2608<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2609heap and returns a pointer to it.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2610
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2611<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2612
2613<p>The '<tt>malloc</tt>' instruction allocates
2614<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswella92e5862004-02-24 16:13:56 +0000[diff] [blame]2615bytes of memory from the operating system and returns a pointer of the
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2616appropriate type to the program. If "NumElements" is specified, it is the
2617number of elements allocated. If an alignment is specified, the value result
2618of the allocation is guaranteed to be aligned to at least that boundary. If
2619not specified, or if zero, the target can choose to align the allocation on any
2620convenient boundary.</p>
2621
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2622<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2623
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2624<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2625
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2626<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2627a pointer is returned.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2628
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2629<h5>Example:</h5>
2630
2631<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2632 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2633
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]2634 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2635 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2636 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2637 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2638 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2639</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2640</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2641
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2642<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2643<div class="doc_subsubsection">
2644 <a name="i_free">'<tt>free</tt>' Instruction</a>
2645</div>
2646
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2647<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2648
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2649<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2650
2651<pre>
2652 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2653</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2654
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2655<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2656
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2657<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2658memory heap to be reallocated in the future.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2659
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2660<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2661
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2662<p>'<tt>value</tt>' shall be a pointer value that points to a value
2663that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2664instruction.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2665
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2666<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2667
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2668<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2669after this instruction executes.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2670
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2671<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2672
2673<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2674 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2675 free [4 x i8]* %array
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2676</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2677</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2678
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2679<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2680<div class="doc_subsubsection">
2681 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2682</div>
2683
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2684<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2685
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2686<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2687
2688<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2689 &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]2690</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2691
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2692<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2693
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2694<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
2695currently executing function, to be automatically released when this function
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2696returns to its caller.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2697
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2698<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2699
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2700<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2701bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2702appropriate type to the program. If "NumElements" is specified, it is the
2703number of elements allocated. If an alignment is specified, the value result
2704of the allocation is guaranteed to be aligned to at least that boundary. If
2705not specified, or if zero, the target can choose to align the allocation on any
2706convenient boundary.</p>
2707
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2708<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2709
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2710<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2711
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2712<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2713memory is automatically released when the function returns. The '<tt>alloca</tt>'
2714instruction is commonly used to represent automatic variables that must
2715have an address available. When the function returns (either with the <tt><a
John Criswellc932bef2005-05-12 16:55:34 +0000[diff] [blame]2716 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]2717instructions), the memory is reclaimed.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2718
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2719<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2720
2721<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2722 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2723 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2724 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2725 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2726</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2727</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2728
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2729<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2730<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2731Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2732<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2733<h5>Syntax:</h5>
Christopher Lambbff50202007-04-21 08:16:25 +0000[diff] [blame]2734<pre> &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br> &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br></pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2735<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2736<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2737<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2738<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2739address from which to load. The pointer must point to a <a
Chris Lattner10ee9652004-06-03 22:57:15 +0000[diff] [blame]2740 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2741marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2742the number or order of execution of this <tt>load</tt> with other
2743volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2744instructions. </p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2745<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2746<p>The location of memory pointed to is loaded.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2747<h5>Examples:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2748<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2749 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2750 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2751 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2752</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2753</div>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2754<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2755<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2756Instruction</a> </div>
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]2757<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2758<h5>Syntax:</h5>
Christopher Lambbff50202007-04-21 08:16:25 +0000[diff] [blame]2759<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
2760 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2761</pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2762<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2763<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2764<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2765<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2766to store and an address at which to store it. The type of the '<tt>&lt;pointer&gt;</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2767operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2768operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2769optimizer is not allowed to modify the number or order of execution of
2770this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2771 href="#i_store">store</a></tt> instructions.</p>
2772<h5>Semantics:</h5>
2773<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2774at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2775<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2776<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2777 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2778 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2779 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2780</pre>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]2781</div>
2782
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2783<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2784<div class="doc_subsubsection">
2785 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2786</div>
2787
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2788<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2789<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2790<pre>
2791 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2792</pre>
2793
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2794<h5>Overview:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2795
2796<p>
2797The '<tt>getelementptr</tt>' instruction is used to get the address of a
2798subelement of an aggregate data structure.</p>
2799
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2800<h5>Arguments:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2801
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2802<p>This instruction takes a list of integer operands that indicate what
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2803elements of the aggregate object to index to. The actual types of the arguments
2804provided depend on the type of the first pointer argument. The
2805'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]2806levels 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]2807structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2808into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2809be sign extended to 64-bit values.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2810
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2811<p>For example, let's consider a C code fragment and how it gets
2812compiled to LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2813
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2814<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2815<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2816struct RT {
2817 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]2818 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2819 char C;
2820};
2821struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]2822 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2823 double Y;
2824 struct RT Z;
2825};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2826
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]2827int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2828 return &amp;s[1].Z.B[5][13];
2829}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2830</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2831</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2832
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2833<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2834
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2835<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2836<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2837%RT = type { i8 , [10 x [20 x i32]], i8 }
2838%ST = type { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2839
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2840define i32* %foo(%ST* %s) {
2841entry:
2842 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2843 ret i32* %reg
2844}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2845</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2846</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2847
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2848<h5>Semantics:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2849
2850<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2851on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2852and <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]2853<a href="#t_integer">integer</a> type but the value will always be sign extended
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2854to 64-bits. <a href="#t_struct">Structure</a> types require <tt>i32</tt>
Reid Spencerc0312692006-12-03 16:53:48 +0000[diff] [blame]2855<b>constants</b>.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2856
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2857<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]2858type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2859}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2860the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2861i8 }</tt>' type, another structure. The third index indexes into the second
2862element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2863array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2864'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2865to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2866
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2867<p>Note that it is perfectly legal to index partially through a
2868structure, returning a pointer to an inner element. Because of this,
2869the LLVM code for the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2870
2871<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2872 define i32* %foo(%ST* %s) {
2873 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2874 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2875 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2876 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2877 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2878 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2879 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2880</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]2881
2882<p>Note that it is undefined to access an array out of bounds: array and
2883pointer indexes must always be within the defined bounds of the array type.
2884The one exception for this rules is zero length arrays. These arrays are
2885defined to be accessible as variable length arrays, which requires access
2886beyond the zero'th element.</p>
2887
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]2888<p>The getelementptr instruction is often confusing. For some more insight
2889into how it works, see <a href="GetElementPtr.html">the getelementptr
2890FAQ</a>.</p>
2891
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2892<h5>Example:</h5>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]2893
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2894<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2895 <i>; yields [12 x i8]*:aptr</i>
2896 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2897</pre>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2898</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]2899
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2900<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]2901<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2902</div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2903<div class="doc_text">
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]2904<p>The instructions in this category are the conversion instructions (casting)
2905which all take a single operand and a type. They perform various bit conversions
2906on the operand.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2907</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2908
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2909<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2910<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2911 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2912</div>
2913<div class="doc_text">
2914
2915<h5>Syntax:</h5>
2916<pre>
2917 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2918</pre>
2919
2920<h5>Overview:</h5>
2921<p>
2922The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2923</p>
2924
2925<h5>Arguments:</h5>
2926<p>
2927The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2928be an <a href="#t_integer">integer</a> type, and a type that specifies the size
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2929and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2930type. The bit size of <tt>value</tt> must be larger than the bit size of
2931<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2932
2933<h5>Semantics:</h5>
2934<p>
2935The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2936and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2937larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2938It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2939
2940<h5>Example:</h5>
2941<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2942 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2943 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
2944 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2945</pre>
2946</div>
2947
2948<!-- _______________________________________________________________________ -->
2949<div class="doc_subsubsection">
2950 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2951</div>
2952<div class="doc_text">
2953
2954<h5>Syntax:</h5>
2955<pre>
2956 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2957</pre>
2958
2959<h5>Overview:</h5>
2960<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2961<tt>ty2</tt>.</p>
2962
2963
2964<h5>Arguments:</h5>
2965<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2966<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2967also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2968<tt>value</tt> must be smaller than the bit size of the destination type,
2969<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2970
2971<h5>Semantics:</h5>
2972<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Chris Lattnerc87f3df2007-05-24 19:13:27 +0000[diff] [blame]2973bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2974
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]2975<p>When zero extending from i1, the result will always be either 0 or 1.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2976
2977<h5>Example:</h5>
2978<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2979 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2980 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2981</pre>
2982</div>
2983
2984<!-- _______________________________________________________________________ -->
2985<div class="doc_subsubsection">
2986 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
2987</div>
2988<div class="doc_text">
2989
2990<h5>Syntax:</h5>
2991<pre>
2992 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2993</pre>
2994
2995<h5>Overview:</h5>
2996<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
2997
2998<h5>Arguments:</h5>
2999<p>
3000The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3001<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3002also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3003<tt>value</tt> must be smaller than the bit size of the destination type,
3004<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3005
3006<h5>Semantics:</h5>
3007<p>
3008The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3009bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
Chris Lattnerc87f3df2007-05-24 19:13:27 +0000[diff] [blame]3010the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3011
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3012<p>When sign extending from i1, the extension always results in -1 or 0.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3013
3014<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3015<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3016 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3017 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3018</pre>
3019</div>
3020
3021<!-- _______________________________________________________________________ -->
3022<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]3023 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3024</div>
3025
3026<div class="doc_text">
3027
3028<h5>Syntax:</h5>
3029
3030<pre>
3031 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3032</pre>
3033
3034<h5>Overview:</h5>
3035<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3036<tt>ty2</tt>.</p>
3037
3038
3039<h5>Arguments:</h5>
3040<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3041 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3042cast it to. The size of <tt>value</tt> must be larger than the size of
3043<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3044<i>no-op cast</i>.</p>
3045
3046<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3047<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3048<a href="#t_floating">floating point</a> type to a smaller
3049<a href="#t_floating">floating point</a> type. If the value cannot fit within
3050the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]3051
3052<h5>Example:</h5>
3053<pre>
3054 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3055 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3056</pre>
3057</div>
3058
3059<!-- _______________________________________________________________________ -->
3060<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3061 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3062</div>
3063<div class="doc_text">
3064
3065<h5>Syntax:</h5>
3066<pre>
3067 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3068</pre>
3069
3070<h5>Overview:</h5>
3071<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3072floating point value.</p>
3073
3074<h5>Arguments:</h5>
3075<p>The '<tt>fpext</tt>' instruction takes a
3076<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3077and a <a href="#t_floating">floating point</a> type to cast it to. The source
3078type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3079
3080<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3081<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3082<a href="#t_floating">floating point</a> type to a larger
3083<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3084used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3085<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]3086
3087<h5>Example:</h5>
3088<pre>
3089 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3090 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3091</pre>
3092</div>
3093
3094<!-- _______________________________________________________________________ -->
3095<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]3096 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3097</div>
3098<div class="doc_text">
3099
3100<h5>Syntax:</h5>
3101<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3102 &lt;result&gt; = fptoui &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3103</pre>
3104
3105<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3106<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3107unsigned integer equivalent of type <tt>ty2</tt>.
3108</p>
3109
3110<h5>Arguments:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3111<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3112<a href="#t_floating">floating point</a> value, and a type to cast it to, which
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3113must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3114
3115<h5>Semantics:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3116<p> The '<tt>fptoui</tt>' instruction converts its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3117<a href="#t_floating">floating point</a> operand into the nearest (rounding
3118towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3119the results are undefined.</p>
3120
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3121<p>When converting to i1, the conversion is done as a comparison against
3122zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3123If the <tt>value</tt> was non-zero, the i1 result will be <tt>true</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3124
3125<h5>Example:</h5>
3126<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3127 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
3128 %Y = fptoui float 1.0E+300 to i1 <i>; yields i1:true</i>
3129 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3130</pre>
3131</div>
3132
3133<!-- _______________________________________________________________________ -->
3134<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3135 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3136</div>
3137<div class="doc_text">
3138
3139<h5>Syntax:</h5>
3140<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3141 &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]3142</pre>
3143
3144<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3145<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3146<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]3147</p>
3148
3149
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3150<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3151<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]3152<a href="#t_floating">floating point</a> value, and a type to cast it to, which
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3153must also be an <a href="#t_integer">integer</a> type.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3154
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3155<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3156<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3157<a href="#t_floating">floating point</a> operand into the nearest (rounding
3158towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3159the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3160
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3161<p>When converting to i1, the conversion is done as a comparison against
3162zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3163If the <tt>value</tt> was non-zero, the i1 result will be <tt>true</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3164
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3165<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3166<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3167 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
3168 %Y = fptosi float 1.0E-247 to i1 <i>; yields i1:true</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3169 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3170</pre>
3171</div>
3172
3173<!-- _______________________________________________________________________ -->
3174<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3175 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3176</div>
3177<div class="doc_text">
3178
3179<h5>Syntax:</h5>
3180<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3181 &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]3182</pre>
3183
3184<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3185<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3186integer and converts that value to the <tt>ty2</tt> type.</p>
3187
3188
3189<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3190<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be an
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3191<a href="#t_integer">integer</a> value, and a type to cast it to, which must
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3192be a <a href="#t_floating">floating point</a> type.</p>
3193
3194<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3195<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3196integer quantity and converts it to the corresponding floating point value. If
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]3197the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3198
3199
3200<h5>Example:</h5>
3201<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3202 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3203 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3204</pre>
3205</div>
3206
3207<!-- _______________________________________________________________________ -->
3208<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3209 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3210</div>
3211<div class="doc_text">
3212
3213<h5>Syntax:</h5>
3214<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3215 &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]3216</pre>
3217
3218<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3219<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3220integer and converts that value to the <tt>ty2</tt> type.</p>
3221
3222<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3223<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be an
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3224<a href="#t_integer">integer</a> value, and a type to cast it to, which must be
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3225a <a href="#t_floating">floating point</a> type.</p>
3226
3227<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3228<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3229integer quantity and converts it to the corresponding floating point value. If
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]3230the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3231
3232<h5>Example:</h5>
3233<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3234 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3235 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3236</pre>
3237</div>
3238
3239<!-- _______________________________________________________________________ -->
3240<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3241 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3242</div>
3243<div class="doc_text">
3244
3245<h5>Syntax:</h5>
3246<pre>
3247 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3248</pre>
3249
3250<h5>Overview:</h5>
3251<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3252the integer type <tt>ty2</tt>.</p>
3253
3254<h5>Arguments:</h5>
3255<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3256must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3257<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3258
3259<h5>Semantics:</h5>
3260<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3261<tt>ty2</tt> by interpreting the pointer value as an integer and either
3262truncating or zero extending that value to the size of the integer type. If
3263<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3264<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3265are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3266change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3267
3268<h5>Example:</h5>
3269<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3270 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3271 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3272</pre>
3273</div>
3274
3275<!-- _______________________________________________________________________ -->
3276<div class="doc_subsubsection">
3277 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3278</div>
3279<div class="doc_text">
3280
3281<h5>Syntax:</h5>
3282<pre>
3283 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3284</pre>
3285
3286<h5>Overview:</h5>
3287<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3288a pointer type, <tt>ty2</tt>.</p>
3289
3290<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3291<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3292value to cast, and a type to cast it to, which must be a
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]3293<a href="#t_pointer">pointer</a> type.
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3294
3295<h5>Semantics:</h5>
3296<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3297<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3298the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3299size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3300the size of a pointer then a zero extension is done. If they are the same size,
3301nothing is done (<i>no-op cast</i>).</p>
3302
3303<h5>Example:</h5>
3304<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3305 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3306 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3307 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3308</pre>
3309</div>
3310
3311<!-- _______________________________________________________________________ -->
3312<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3313 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3314</div>
3315<div class="doc_text">
3316
3317<h5>Syntax:</h5>
3318<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3319 &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]3320</pre>
3321
3322<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3323<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3324<tt>ty2</tt> without changing any bits.</p>
3325
3326<h5>Arguments:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3327<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3328a first class value, and a type to cast it to, which must also be a <a
3329 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencere3db84c2007-01-09 20:08:58 +0000[diff] [blame]3330and the destination type, <tt>ty2</tt>, must be identical. If the source
3331type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3332
3333<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3334<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3335<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3336this conversion. The conversion is done as if the <tt>value</tt> had been
3337stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3338converted to other pointer types with this instruction. To convert pointers to
3339other types, use the <a href="#i_inttoptr">inttoptr</a> or
3340<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3341
3342<h5>Example:</h5>
3343<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3344 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3345 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3346 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3347</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3348</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3349
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3350<!-- ======================================================================= -->
3351<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3352<div class="doc_text">
3353<p>The instructions in this category are the "miscellaneous"
3354instructions, which defy better classification.</p>
3355</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3356
3357<!-- _______________________________________________________________________ -->
3358<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3359</div>
3360<div class="doc_text">
3361<h5>Syntax:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3362<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3363</pre>
3364<h5>Overview:</h5>
3365<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3366of its two integer operands.</p>
3367<h5>Arguments:</h5>
3368<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3369the condition code indicating the kind of comparison to perform. It is not
3370a value, just a keyword. The possible condition code are:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3371<ol>
3372 <li><tt>eq</tt>: equal</li>
3373 <li><tt>ne</tt>: not equal </li>
3374 <li><tt>ugt</tt>: unsigned greater than</li>
3375 <li><tt>uge</tt>: unsigned greater or equal</li>
3376 <li><tt>ult</tt>: unsigned less than</li>
3377 <li><tt>ule</tt>: unsigned less or equal</li>
3378 <li><tt>sgt</tt>: signed greater than</li>
3379 <li><tt>sge</tt>: signed greater or equal</li>
3380 <li><tt>slt</tt>: signed less than</li>
3381 <li><tt>sle</tt>: signed less or equal</li>
3382</ol>
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3383<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3384<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3385<h5>Semantics:</h5>
3386<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3387the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3388yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3389<ol>
3390 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3391 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3392 </li>
3393 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3394 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3395 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3396 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3397 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3398 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3399 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3400 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3401 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3402 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3403 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3404 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3405 <li><tt>sge</tt>: interprets the operands as signed values and yields
3406 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3407 <li><tt>slt</tt>: interprets the operands as signed values and yields
3408 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3409 <li><tt>sle</tt>: interprets the operands as signed values and yields
3410 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3411</ol>
3412<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3413values are compared as if they were integers.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3414
3415<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3416<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3417 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3418 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3419 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3420 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3421 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3422</pre>
3423</div>
3424
3425<!-- _______________________________________________________________________ -->
3426<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3427</div>
3428<div class="doc_text">
3429<h5>Syntax:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3430<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3431</pre>
3432<h5>Overview:</h5>
3433<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3434of its floating point operands.</p>
3435<h5>Arguments:</h5>
3436<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3437the condition code indicating the kind of comparison to perform. It is not
3438a value, just a keyword. The possible condition code are:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3439<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3440 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3441 <li><tt>oeq</tt>: ordered and equal</li>
3442 <li><tt>ogt</tt>: ordered and greater than </li>
3443 <li><tt>oge</tt>: ordered and greater than or equal</li>
3444 <li><tt>olt</tt>: ordered and less than </li>
3445 <li><tt>ole</tt>: ordered and less than or equal</li>
3446 <li><tt>one</tt>: ordered and not equal</li>
3447 <li><tt>ord</tt>: ordered (no nans)</li>
3448 <li><tt>ueq</tt>: unordered or equal</li>
3449 <li><tt>ugt</tt>: unordered or greater than </li>
3450 <li><tt>uge</tt>: unordered or greater than or equal</li>
3451 <li><tt>ult</tt>: unordered or less than </li>
3452 <li><tt>ule</tt>: unordered or less than or equal</li>
3453 <li><tt>une</tt>: unordered or not equal</li>
3454 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3455 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3456</ol>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3457<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer02e0d1d2006-12-06 07:08:07 +0000[diff] [blame]3458<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3459<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3460<a href="#t_floating">floating point</a> typed. They must have identical
3461types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3462<h5>Semantics:</h5>
3463<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3464the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3465yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3466<ol>
3467 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3468 <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]3469 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3470 <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]3471 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3472 <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]3473 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3474 <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]3475 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3476 <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]3477 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3478 <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]3479 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3480 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3481 <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]3482 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3483 <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]3484 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3485 <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]3486 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3487 <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]3488 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3489 <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]3490 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3491 <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]3492 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3493 <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]3494 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3495</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3496
3497<h5>Example:</h5>
3498<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3499 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3500 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3501 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3502</pre>
3503</div>
3504
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3505<!-- _______________________________________________________________________ -->
3506<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3507Instruction</a> </div>
3508<div class="doc_text">
3509<h5>Syntax:</h5>
3510<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3511<h5>Overview:</h5>
3512<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3513the SSA graph representing the function.</p>
3514<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3515<p>The type of the incoming values is specified with the first type
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3516field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3517as arguments, with one pair for each predecessor basic block of the
3518current block. Only values of <a href="#t_firstclass">first class</a>
3519type may be used as the value arguments to the PHI node. Only labels
3520may be used as the label arguments.</p>
3521<p>There must be no non-phi instructions between the start of a basic
3522block and the PHI instructions: i.e. PHI instructions must be first in
3523a basic block.</p>
3524<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3525<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
3526specified by the pair corresponding to the predecessor basic block that executed
3527just prior to the current block.</p>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3528<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3529<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]3530</div>
3531
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3532<!-- _______________________________________________________________________ -->
3533<div class="doc_subsubsection">
3534 <a name="i_select">'<tt>select</tt>' Instruction</a>
3535</div>
3536
3537<div class="doc_text">
3538
3539<h5>Syntax:</h5>
3540
3541<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3542 &lt;result&gt; = select i1 &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3543</pre>
3544
3545<h5>Overview:</h5>
3546
3547<p>
3548The '<tt>select</tt>' instruction is used to choose one value based on a
3549condition, without branching.
3550</p>
3551
3552
3553<h5>Arguments:</h5>
3554
3555<p>
3556The '<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.
3557</p>
3558
3559<h5>Semantics:</h5>
3560
3561<p>
3562If the boolean condition evaluates to true, the instruction returns the first
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3563value argument; otherwise, it returns the second value argument.
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3564</p>
3565
3566<h5>Example:</h5>
3567
3568<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3569 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3570</pre>
3571</div>
3572
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]3573
3574<!-- _______________________________________________________________________ -->
3575<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3576 <a name="i_call">'<tt>call</tt>' Instruction</a>
3577</div>
3578
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3579<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3580
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3581<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3582<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]3583 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] &lt;ty&gt; [&lt;fnty&gt;*] &lt;fnptrval&gt;(&lt;param list&gt;)
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3584</pre>
3585
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3586<h5>Overview:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3587
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3588<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3589
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3590<h5>Arguments:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3591
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3592<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3593
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3594<ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3595 <li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3596 <p>The optional "tail" marker indicates whether the callee function accesses
3597 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3598 function call is eligible for tail call optimization. Note that calls may
3599 be marked "tail" even if they do not occur before a <a
3600 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3601 </li>
3602 <li>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3603 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3604 convention</a> the call should use. If none is specified, the call defaults
3605 to using C calling conventions.
3606 </li>
3607 <li>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]3608 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
3609 the type of the return value. Functions that return no value are marked
3610 <tt><a href="#t_void">void</a></tt>.</p>
3611 </li>
3612 <li>
3613 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
3614 value being invoked. The argument types must match the types implied by
3615 this signature. This type can be omitted if the function is not varargs
3616 and if the function type does not return a pointer to a function.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3617 </li>
3618 <li>
3619 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3620 be invoked. In most cases, this is a direct function invocation, but
3621 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3622 to function value.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3623 </li>
3624 <li>
3625 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencerd845d162005-05-01 22:22:57 +0000[diff] [blame]3626 function signature argument types. All arguments must be of
3627 <a href="#t_firstclass">first class</a> type. If the function signature
3628 indicates the function accepts a variable number of arguments, the extra
3629 arguments can be specified.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3630 </li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3631</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3632
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3633<h5>Semantics:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3634
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3635<p>The '<tt>call</tt>' instruction is used to cause control flow to
3636transfer to a specified function, with its incoming arguments bound to
3637the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3638instruction in the called function, control flow continues with the
3639instruction after the function call, and the return value of the
3640function is bound to the result argument. This is a simpler case of
3641the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3642
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3643<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3644
3645<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]3646 %retval = call i32 @test(i32 %argc)
3647 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42);
3648 %X = tail call i32 @foo()
3649 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo()
3650 %Z = call void %foo(i8 97 signext)
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3651</pre>
3652
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3653</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3654
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3655<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3656<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]3657 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3658</div>
3659
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3660<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3661
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3662<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3663
3664<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3665 &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]3666</pre>
3667
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3668<h5>Overview:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3669
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3670<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3671the "variable argument" area of a function call. It is used to implement the
3672<tt>va_arg</tt> macro in C.</p>
3673
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3674<h5>Arguments:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3675
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3676<p>This instruction takes a <tt>va_list*</tt> value and the type of
3677the argument. It returns a value of the specified argument type and
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3678increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3679actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3680
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3681<h5>Semantics:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3682
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3683<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3684type from the specified <tt>va_list</tt> and causes the
3685<tt>va_list</tt> to point to the next argument. For more information,
3686see the variable argument handling <a href="#int_varargs">Intrinsic
3687Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3688
3689<p>It is legal for this instruction to be called in a function which does not
3690take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3691function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3692
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3693<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3694href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3695argument.</p>
3696
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3697<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3698
3699<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3700
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3701</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3702
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3703<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3704<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3705<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3706
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3707<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3708
3709<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]3710well known names and semantics and are required to follow certain restrictions.
3711Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3712language that does not require changing all of the transformations in LLVM when
Gabor Greifa54634a2007-07-06 22:07:22 +0000[diff] [blame]3713adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3714
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3715<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3716prefix is reserved in LLVM for intrinsic names; thus, function names may not
3717begin with this prefix. Intrinsic functions must always be external functions:
3718you cannot define the body of intrinsic functions. Intrinsic functions may
3719only be used in call or invoke instructions: it is illegal to take the address
3720of an intrinsic function. Additionally, because intrinsic functions are part
3721of the LLVM language, it is required if any are added that they be documented
3722here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3723
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]3724<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
3725a family of functions that perform the same operation but on different data
3726types. Because LLVM can represent over 8 million different integer types,
3727overloading is used commonly to allow an intrinsic function to operate on any
3728integer type. One or more of the argument types or the result type can be
3729overloaded to accept any integer type. Argument types may also be defined as
3730exactly matching a previous argument's type or the result type. This allows an
3731intrinsic function which accepts multiple arguments, but needs all of them to
3732be of the same type, to only be overloaded with respect to a single argument or
3733the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3734
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]3735<p>Overloaded intrinsics will have the names of its overloaded argument types
3736encoded into its function name, each preceded by a period. Only those types
3737which are overloaded result in a name suffix. Arguments whose type is matched
3738against another type do not. For example, the <tt>llvm.ctpop</tt> function can
3739take an integer of any width and returns an integer of exactly the same integer
3740width. This leads to a family of functions such as
3741<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
3742Only one type, the return type, is overloaded, and only one type suffix is
3743required. Because the argument's type is matched against the return type, it
3744does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]3745
3746<p>To learn how to add an intrinsic function, please see the
3747<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3748</p>
3749
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3750</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3751
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3752<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3753<div class="doc_subsection">
3754 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3755</div>
3756
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3757<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3758
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3759<p>Variable argument support is defined in LLVM with the <a
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]3760 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3761intrinsic functions. These functions are related to the similarly
3762named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3763
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3764<p>All of these functions operate on arguments that use a
3765target-specific value type "<tt>va_list</tt>". The LLVM assembly
3766language reference manual does not define what this type is, so all
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3767transformations should be prepared to handle these functions regardless of
3768the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3769
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]3770<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]3771instruction and the variable argument handling intrinsic functions are
3772used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3773
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3774<div class="doc_code">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3775<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3776define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3777 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3778 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3779 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3780 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3781
3782 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3783 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3784
3785 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3786 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3787 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3788 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3789 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3790
3791 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3792 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3793 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3794}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3795
3796declare void @llvm.va_start(i8*)
3797declare void @llvm.va_copy(i8*, i8*)
3798declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3799</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3800</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3801
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3802</div>
3803
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3804<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3805<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3806 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3807</div>
3808
3809
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3810<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3811<h5>Syntax:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3812<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3813<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3814<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3815<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3816href="#i_va_arg">va_arg</a></tt>.</p>
3817
3818<h5>Arguments:</h5>
3819
3820<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3821
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3822<h5>Semantics:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3823
3824<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3825macro available in C. In a target-dependent way, it initializes the
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3826<tt>va_list</tt> element to which the argument points, so that the next call to
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3827<tt>va_arg</tt> will produce the first variable argument passed to the function.
3828Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3829last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3830
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3831</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3832
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3833<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3834<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3835 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3836</div>
3837
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3838<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3839<h5>Syntax:</h5>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3840<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3841<h5>Overview:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3842
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3843<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3844which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3845or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3846
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3847<h5>Arguments:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3848
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3849<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3850
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3851<h5>Semantics:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3852
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3853<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3854macro available in C. In a target-dependent way, it destroys the
3855<tt>va_list</tt> element to which the argument points. Calls to <a
3856href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
3857<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
3858<tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3859
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3860</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3861
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3862<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3863<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3864 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3865</div>
3866
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3867<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3868
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3869<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3870
3871<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3872 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3873</pre>
3874
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3875<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3876
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3877<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
3878from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3879
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3880<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3881
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3882<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]3883The 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]3884
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3885
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3886<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3887
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3888<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
3889macro available in C. In a target-dependent way, it copies the source
3890<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
3891intrinsic is necessary because the <tt><a href="#int_va_start">
3892llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
3893example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3894
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3895</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3896
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3897<!-- ======================================================================= -->
3898<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3899 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3900</div>
3901
3902<div class="doc_text">
3903
3904<p>
3905LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3906Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3907These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3908stack</a>, as well as garbage collector implementations that require <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3909href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3910Front-ends for type-safe garbage collected languages should generate these
3911intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3912href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3913</p>
3914</div>
3915
3916<!-- _______________________________________________________________________ -->
3917<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3918 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3919</div>
3920
3921<div class="doc_text">
3922
3923<h5>Syntax:</h5>
3924
3925<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3926 declare void @llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3927</pre>
3928
3929<h5>Overview:</h5>
3930
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]3931<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]3932the code generator, and allows some metadata to be associated with it.</p>
3933
3934<h5>Arguments:</h5>
3935
3936<p>The first argument specifies the address of a stack object that contains the
3937root pointer. The second pointer (which must be either a constant or a global
3938value address) contains the meta-data to be associated with the root.</p>
3939
3940<h5>Semantics:</h5>
3941
3942<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3943location. At compile-time, the code generator generates information to allow
3944the runtime to find the pointer at GC safe points.
3945</p>
3946
3947</div>
3948
3949
3950<!-- _______________________________________________________________________ -->
3951<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3952 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3953</div>
3954
3955<div class="doc_text">
3956
3957<h5>Syntax:</h5>
3958
3959<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3960 declare i8 * @llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3961</pre>
3962
3963<h5>Overview:</h5>
3964
3965<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3966locations, allowing garbage collector implementations that require read
3967barriers.</p>
3968
3969<h5>Arguments:</h5>
3970
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]3971<p>The second argument is the address to read from, which should be an address
3972allocated from the garbage collector. The first object is a pointer to the
3973start of the referenced object, if needed by the language runtime (otherwise
3974null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3975
3976<h5>Semantics:</h5>
3977
3978<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3979instruction, but may be replaced with substantially more complex code by the
3980garbage collector runtime, as needed.</p>
3981
3982</div>
3983
3984
3985<!-- _______________________________________________________________________ -->
3986<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3987 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3988</div>
3989
3990<div class="doc_text">
3991
3992<h5>Syntax:</h5>
3993
3994<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3995 declare void @llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3996</pre>
3997
3998<h5>Overview:</h5>
3999
4000<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4001locations, allowing garbage collector implementations that require write
4002barriers (such as generational or reference counting collectors).</p>
4003
4004<h5>Arguments:</h5>
4005
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]4006<p>The first argument is the reference to store, the second is the start of the
4007object to store it to, and the third is the address of the field of Obj to
4008store to. If the runtime does not require a pointer to the object, Obj may be
4009null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4010
4011<h5>Semantics:</h5>
4012
4013<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4014instruction, but may be replaced with substantially more complex code by the
4015garbage collector runtime, as needed.</p>
4016
4017</div>
4018
4019
4020
4021<!-- ======================================================================= -->
4022<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4023 <a name="int_codegen">Code Generator Intrinsics</a>
4024</div>
4025
4026<div class="doc_text">
4027<p>
4028These intrinsics are provided by LLVM to expose special features that may only
4029be implemented with code generator support.
4030</p>
4031
4032</div>
4033
4034<!-- _______________________________________________________________________ -->
4035<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4036 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4037</div>
4038
4039<div class="doc_text">
4040
4041<h5>Syntax:</h5>
4042<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4043 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4044</pre>
4045
4046<h5>Overview:</h5>
4047
4048<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]4049The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4050target-specific value indicating the return address of the current function
4051or one of its callers.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4052</p>
4053
4054<h5>Arguments:</h5>
4055
4056<p>
4057The argument to this intrinsic indicates which function to return the address
4058for. Zero indicates the calling function, one indicates its caller, etc. The
4059argument is <b>required</b> to be a constant integer value.
4060</p>
4061
4062<h5>Semantics:</h5>
4063
4064<p>
4065The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4066the return address of the specified call frame, or zero if it cannot be
4067identified. The value returned by this intrinsic is likely to be incorrect or 0
4068for arguments other than zero, so it should only be used for debugging purposes.
4069</p>
4070
4071<p>
4072Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]4073aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4074source-language caller.
4075</p>
4076</div>
4077
4078
4079<!-- _______________________________________________________________________ -->
4080<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4081 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4082</div>
4083
4084<div class="doc_text">
4085
4086<h5>Syntax:</h5>
4087<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4088 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4089</pre>
4090
4091<h5>Overview:</h5>
4092
4093<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]4094The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4095target-specific frame pointer value for the specified stack frame.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4096</p>
4097
4098<h5>Arguments:</h5>
4099
4100<p>
4101The argument to this intrinsic indicates which function to return the frame
4102pointer for. Zero indicates the calling function, one indicates its caller,
4103etc. The argument is <b>required</b> to be a constant integer value.
4104</p>
4105
4106<h5>Semantics:</h5>
4107
4108<p>
4109The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4110the frame address of the specified call frame, or zero if it cannot be
4111identified. The value returned by this intrinsic is likely to be incorrect or 0
4112for arguments other than zero, so it should only be used for debugging purposes.
4113</p>
4114
4115<p>
4116Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]4117aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4118source-language caller.
4119</p>
4120</div>
4121
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4122<!-- _______________________________________________________________________ -->
4123<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4124 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4125</div>
4126
4127<div class="doc_text">
4128
4129<h5>Syntax:</h5>
4130<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4131 declare i8 *@llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4132</pre>
4133
4134<h5>Overview:</h5>
4135
4136<p>
4137The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4138the function stack, for use with <a href="#int_stackrestore">
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4139<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4140features like scoped automatic variable sized arrays in C99.
4141</p>
4142
4143<h5>Semantics:</h5>
4144
4145<p>
4146This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4147href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4148<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4149<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4150state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4151practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4152that were allocated after the <tt>llvm.stacksave</tt> was executed.
4153</p>
4154
4155</div>
4156
4157<!-- _______________________________________________________________________ -->
4158<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4159 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4160</div>
4161
4162<div class="doc_text">
4163
4164<h5>Syntax:</h5>
4165<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4166 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4167</pre>
4168
4169<h5>Overview:</h5>
4170
4171<p>
4172The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4173the function stack to the state it was in when the corresponding <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4174href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4175useful for implementing language features like scoped automatic variable sized
4176arrays in C99.
4177</p>
4178
4179<h5>Semantics:</h5>
4180
4181<p>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4182See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4183</p>
4184
4185</div>
4186
4187
4188<!-- _______________________________________________________________________ -->
4189<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4190 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4191</div>
4192
4193<div class="doc_text">
4194
4195<h5>Syntax:</h5>
4196<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4197 declare void @llvm.prefetch(i8 * &lt;address&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4198 i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4199</pre>
4200
4201<h5>Overview:</h5>
4202
4203
4204<p>
4205The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4206a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4207no
4208effect on the behavior of the program but can change its performance
Chris Lattnerff851072005-02-28 19:47:14 +0000[diff] [blame]4209characteristics.
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4210</p>
4211
4212<h5>Arguments:</h5>
4213
4214<p>
4215<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4216determining if the fetch should be for a read (0) or write (1), and
4217<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattnerd3e641c2005-03-07 20:31:38 +0000[diff] [blame]4218locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4219<tt>locality</tt> arguments must be constant integers.
4220</p>
4221
4222<h5>Semantics:</h5>
4223
4224<p>
4225This intrinsic does not modify the behavior of the program. In particular,
4226prefetches cannot trap and do not produce a value. On targets that support this
4227intrinsic, the prefetch can provide hints to the processor cache for better
4228performance.
4229</p>
4230
4231</div>
4232
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4233<!-- _______________________________________________________________________ -->
4234<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4235 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4236</div>
4237
4238<div class="doc_text">
4239
4240<h5>Syntax:</h5>
4241<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4242 declare void @llvm.pcmarker( i32 &lt;id&gt; )
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4243</pre>
4244
4245<h5>Overview:</h5>
4246
4247
4248<p>
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4249The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4250(PC) in a region of
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4251code to simulators and other tools. The method is target specific, but it is
4252expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohendc6bfea2005-11-11 02:15:27 +0000[diff] [blame]4253The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnere64d41d2005-11-15 06:07:55 +0000[diff] [blame]4254after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb40261e2006-03-24 07:16:10 +0000[diff] [blame]4255optimizations. The intended use is to be inserted after optimizations to allow
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4256correlations of simulation runs.
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4257</p>
4258
4259<h5>Arguments:</h5>
4260
4261<p>
4262<tt>id</tt> is a numerical id identifying the marker.
4263</p>
4264
4265<h5>Semantics:</h5>
4266
4267<p>
4268This intrinsic does not modify the behavior of the program. Backends that do not
4269support this intrinisic may ignore it.
4270</p>
4271
4272</div>
4273
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4274<!-- _______________________________________________________________________ -->
4275<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4276 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4277</div>
4278
4279<div class="doc_text">
4280
4281<h5>Syntax:</h5>
4282<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4283 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4284</pre>
4285
4286<h5>Overview:</h5>
4287
4288
4289<p>
4290The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4291counter register (or similar low latency, high accuracy clocks) on those targets
4292that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4293As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4294should only be used for small timings.
4295</p>
4296
4297<h5>Semantics:</h5>
4298
4299<p>
4300When directly supported, reading the cycle counter should not modify any memory.
4301Implementations are allowed to either return a application specific value or a
4302system wide value. On backends without support, this is lowered to a constant 0.
4303</p>
4304
4305</div>
4306
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4307<!-- ======================================================================= -->
4308<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4309 <a name="int_libc">Standard C Library Intrinsics</a>
4310</div>
4311
4312<div class="doc_text">
4313<p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4314LLVM provides intrinsics for a few important standard C library functions.
4315These intrinsics allow source-language front-ends to pass information about the
4316alignment of the pointer arguments to the code generator, providing opportunity
4317for more efficient code generation.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4318</p>
4319
4320</div>
4321
4322<!-- _______________________________________________________________________ -->
4323<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4324 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4325</div>
4326
4327<div class="doc_text">
4328
4329<h5>Syntax:</h5>
4330<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4331 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4332 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4333 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4334 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4335</pre>
4336
4337<h5>Overview:</h5>
4338
4339<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4340The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4341location to the destination location.
4342</p>
4343
4344<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4345Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4346intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4347</p>
4348
4349<h5>Arguments:</h5>
4350
4351<p>
4352The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4353the source. The third argument is an integer argument
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4354specifying the number of bytes to copy, and the fourth argument is the alignment
4355of the source and destination locations.
4356</p>
4357
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4358<p>
4359If 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]4360the caller guarantees that both the source and destination pointers are aligned
4361to that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4362</p>
4363
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4364<h5>Semantics:</h5>
4365
4366<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4367The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4368location to the destination location, which are not allowed to overlap. It
4369copies "len" bytes of memory over. If the argument is known to be aligned to
4370some boundary, this can be specified as the fourth argument, otherwise it should
4371be set to 0 or 1.
4372</p>
4373</div>
4374
4375
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4376<!-- _______________________________________________________________________ -->
4377<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4378 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4379</div>
4380
4381<div class="doc_text">
4382
4383<h5>Syntax:</h5>
4384<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4385 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4386 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4387 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4388 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4389</pre>
4390
4391<h5>Overview:</h5>
4392
4393<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4394The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4395location to the destination location. It is similar to the
4396'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4397</p>
4398
4399<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4400Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4401intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4402</p>
4403
4404<h5>Arguments:</h5>
4405
4406<p>
4407The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4408the source. The third argument is an integer argument
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4409specifying the number of bytes to copy, and the fourth argument is the alignment
4410of the source and destination locations.
4411</p>
4412
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4413<p>
4414If 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]4415the caller guarantees that the source and destination pointers are aligned to
4416that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4417</p>
4418
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4419<h5>Semantics:</h5>
4420
4421<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4422The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4423location to the destination location, which may overlap. It
4424copies "len" bytes of memory over. If the argument is known to be aligned to
4425some boundary, this can be specified as the fourth argument, otherwise it should
4426be set to 0 or 1.
4427</p>
4428</div>
4429
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4430
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4431<!-- _______________________________________________________________________ -->
4432<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4433 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4434</div>
4435
4436<div class="doc_text">
4437
4438<h5>Syntax:</h5>
4439<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4440 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4441 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4442 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4443 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4444</pre>
4445
4446<h5>Overview:</h5>
4447
4448<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4449The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4450byte value.
4451</p>
4452
4453<p>
4454Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4455does not return a value, and takes an extra alignment argument.
4456</p>
4457
4458<h5>Arguments:</h5>
4459
4460<p>
4461The first argument is a pointer to the destination to fill, the second is the
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4462byte value to fill it with, the third argument is an integer
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4463argument specifying the number of bytes to fill, and the fourth argument is the
4464known alignment of destination location.
4465</p>
4466
4467<p>
4468If 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]4469the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4470</p>
4471
4472<h5>Semantics:</h5>
4473
4474<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4475The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4476the
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4477destination location. If the argument is known to be aligned to some boundary,
4478this can be specified as the fourth argument, otherwise it should be set to 0 or
44791.
4480</p>
4481</div>
4482
4483
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]4484<!-- _______________________________________________________________________ -->
4485<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4486 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4487</div>
4488
4489<div class="doc_text">
4490
4491<h5>Syntax:</h5>
4492<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4493 declare float @llvm.sqrt.f32(float %Val)
4494 declare double @llvm.sqrt.f64(double %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4495</pre>
4496
4497<h5>Overview:</h5>
4498
4499<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4500The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4501returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
4502<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4503negative numbers (which allows for better optimization).
4504</p>
4505
4506<h5>Arguments:</h5>
4507
4508<p>
4509The argument and return value are floating point numbers of the same type.
4510</p>
4511
4512<h5>Semantics:</h5>
4513
4514<p>
Dan Gohman33988db2007-07-16 14:37:41 +0000[diff] [blame]4515This function returns the sqrt of the specified operand if it is a nonnegative
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4516floating point number.
4517</p>
4518</div>
4519
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4520<!-- _______________________________________________________________________ -->
4521<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4522 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4523</div>
4524
4525<div class="doc_text">
4526
4527<h5>Syntax:</h5>
4528<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4529 declare float @llvm.powi.f32(float %Val, i32 %power)
4530 declare double @llvm.powi.f64(double %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4531</pre>
4532
4533<h5>Overview:</h5>
4534
4535<p>
4536The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4537specified (positive or negative) power. The order of evaluation of
4538multiplications is not defined.
4539</p>
4540
4541<h5>Arguments:</h5>
4542
4543<p>
4544The second argument is an integer power, and the first is a value to raise to
4545that power.
4546</p>
4547
4548<h5>Semantics:</h5>
4549
4550<p>
4551This function returns the first value raised to the second power with an
4552unspecified sequence of rounding operations.</p>
4553</div>
4554
4555
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4556<!-- ======================================================================= -->
4557<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4558 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4559</div>
4560
4561<div class="doc_text">
4562<p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4563LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4564These allow efficient code generation for some algorithms.
4565</p>
4566
4567</div>
4568
4569<!-- _______________________________________________________________________ -->
4570<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4571 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4572</div>
4573
4574<div class="doc_text">
4575
4576<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4577<p>This is an overloaded intrinsic function. You can use bswap on any integer
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4578type that is an even number of bytes (i.e. BitWidth % 16 == 0).
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4579<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4580 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
4581 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
4582 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4583</pre>
4584
4585<h5>Overview:</h5>
4586
4587<p>
Reid Spencerf361c4f2007-04-02 02:25:19 +0000[diff] [blame]4588The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4589values with an even number of bytes (positive multiple of 16 bits). These are
4590useful for performing operations on data that is not in the target's native
4591byte order.
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4592</p>
4593
4594<h5>Semantics:</h5>
4595
4596<p>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4597The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4598and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4599intrinsic returns an i32 value that has the four bytes of the input i32
4600swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4601i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
4602<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4603additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4604</p>
4605
4606</div>
4607
4608<!-- _______________________________________________________________________ -->
4609<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4610 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4611</div>
4612
4613<div class="doc_text">
4614
4615<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4616<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
4617width. Not all targets support all bit widths however.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4618<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4619 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
4620 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4621 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4622 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
4623 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4624</pre>
4625
4626<h5>Overview:</h5>
4627
4628<p>
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]4629The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4630value.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4631</p>
4632
4633<h5>Arguments:</h5>
4634
4635<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]4636The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]4637integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4638</p>
4639
4640<h5>Semantics:</h5>
4641
4642<p>
4643The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4644</p>
4645</div>
4646
4647<!-- _______________________________________________________________________ -->
4648<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]4649 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4650</div>
4651
4652<div class="doc_text">
4653
4654<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4655<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
4656integer bit width. Not all targets support all bit widths however.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4657<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4658 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
4659 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4660 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4661 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
4662 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4663</pre>
4664
4665<h5>Overview:</h5>
4666
4667<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4668The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4669leading zeros in a variable.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4670</p>
4671
4672<h5>Arguments:</h5>
4673
4674<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]4675The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]4676integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4677</p>
4678
4679<h5>Semantics:</h5>
4680
4681<p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4682The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4683in 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]4684of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4685</p>
4686</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]4687
4688
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4689
4690<!-- _______________________________________________________________________ -->
4691<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]4692 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4693</div>
4694
4695<div class="doc_text">
4696
4697<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4698<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
4699integer bit width. Not all targets support all bit widths however.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4700<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4701 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
4702 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4703 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4704 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
4705 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4706</pre>
4707
4708<h5>Overview:</h5>
4709
4710<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4711The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4712trailing zeros.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4713</p>
4714
4715<h5>Arguments:</h5>
4716
4717<p>
4718The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]4719integer type. The return type must match the argument type.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4720</p>
4721
4722<h5>Semantics:</h5>
4723
4724<p>
4725The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4726in a variable. If the src == 0 then the result is the size in bits of the type
4727of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4728</p>
4729</div>
4730
Reid Spencer8a5799f2007-04-01 08:27:01 +0000[diff] [blame]4731<!-- _______________________________________________________________________ -->
4732<div class="doc_subsubsection">
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]4733 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]4734</div>
4735
4736<div class="doc_text">
4737
4738<h5>Syntax:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]4739<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]4740on any integer bit width.
4741<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4742 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
4743 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]4744</pre>
4745
4746<h5>Overview:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]4747<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]4748range of bits from an integer value and returns them in the same bit width as
4749the original value.</p>
4750
4751<h5>Arguments:</h5>
4752<p>The first argument, <tt>%val</tt> and the result may be integer types of
4753any bit width but they must have the same bit width. The second and third
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4754arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]4755
4756<h5>Semantics:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]4757<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4758of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
4759<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
4760operates in forward mode.</p>
4761<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
4762right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]4763only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
4764<ol>
4765 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
4766 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
4767 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
4768 to determine the number of bits to retain.</li>
4769 <li>A mask of the retained bits is created by shifting a -1 value.</li>
4770 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
4771</ol>
Reid Spencer70845c02007-05-14 16:14:57 +0000[diff] [blame]4772<p>In reverse mode, a similar computation is made except that the bits are
4773returned in the reverse order. So, for example, if <tt>X</tt> has the value
4774<tt>i16 0x0ACF (101011001111)</tt> and we apply
4775<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
4776<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]4777</div>
4778
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]4779<div class="doc_subsubsection">
4780 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
4781</div>
4782
4783<div class="doc_text">
4784
4785<h5>Syntax:</h5>
4786<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
4787on any integer bit width.
4788<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4789 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
4790 declare i29 @llvm.part.set.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi)
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]4791</pre>
4792
4793<h5>Overview:</h5>
4794<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
4795of bits in an integer value with another integer value. It returns the integer
4796with the replaced bits.</p>
4797
4798<h5>Arguments:</h5>
4799<p>The first argument, <tt>%val</tt> and the result may be integer types of
4800any bit width but they must have the same bit width. <tt>%val</tt> is the value
4801whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
4802integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
4803type since they specify only a bit index.</p>
4804
4805<h5>Semantics:</h5>
4806<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
4807of operation: forwards and reverse. If <tt>%lo</tt> is greater than
4808<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
4809operates in forward mode.</p>
4810<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
4811truncating it down to the size of the replacement area or zero extending it
4812up to that size.</p>
4813<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
4814are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
4815in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
4816to the <tt>%hi</tt>th bit.
Reid Spencer146281c2007-05-14 16:50:20 +0000[diff] [blame]4817<p>In reverse mode, a similar computation is made except that the bits are
4818reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
4819<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]4820<h5>Examples:</h5>
4821<pre>
Reid Spencerc70afc32007-04-12 01:03:03 +0000[diff] [blame]4822 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencer146281c2007-05-14 16:50:20 +0000[diff] [blame]4823 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
4824 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
4825 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerc70afc32007-04-12 01:03:03 +0000[diff] [blame]4826 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]4827</pre>
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]4828</div>
4829
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4830<!-- ======================================================================= -->
4831<div class="doc_subsection">
4832 <a name="int_debugger">Debugger Intrinsics</a>
4833</div>
4834
4835<div class="doc_text">
4836<p>
4837The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4838are described in the <a
4839href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4840Debugging</a> document.
4841</p>
4842</div>
4843
4844
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]4845<!-- ======================================================================= -->
4846<div class="doc_subsection">
4847 <a name="int_eh">Exception Handling Intrinsics</a>
4848</div>
4849
4850<div class="doc_text">
4851<p> The LLVM exception handling intrinsics (which all start with
4852<tt>llvm.eh.</tt> prefix), are described in the <a
4853href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
4854Handling</a> document. </p>
4855</div>
4856
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]4857<!-- ======================================================================= -->
4858<div class="doc_subsection">
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]4859 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
4860</div>
4861
4862<div class="doc_text">
4863<p>
4864 These intrinsic functions expand the "universal IR" of LLVM to represent
4865 hardware constructs for atomic operations and memory synchronization. This
4866 provides an interface to the hardware, not an interface to the programmer. It
4867 is aimed at a low enough level to allow any programming models or APIs which
4868 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
Chandler Carruthfd4184352007-07-20 20:14:52 +0000[diff] [blame]4869 hardware behavior. Just as hardware provides a "universal IR" for source
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]4870 languages, it also provides a starting point for developing a "universal"
4871 atomic operation and synchronization IR.
4872</p>
4873<p>
4874 These do <em>not</em> form an API such as high-level threading libraries,
4875 software transaction memory systems, atomic primitives, and intrinsic
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]4876 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]4877 application libraries. The hardware interface provided by LLVM should allow
4878 a clean implementation of all of these APIs and parallel programming models.
4879 No one model or paradigm should be selected above others unless the hardware
4880 itself ubiquitously does so.
4881</p>
4882</div>
4883
4884<!-- _______________________________________________________________________ -->
4885<div class="doc_subsubsection">
4886 <a name="int_lcs">'<tt>llvm.atomic.lcs.*</tt>' Intrinsic</a>
4887</div>
4888<div class="doc_text">
4889<h5>Syntax:</h5>
4890<p>
4891 This is an overloaded intrinsic. You can use <tt>llvm.atomic.lcs</tt> on any
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]4892 integer bit width. Not all targets support all bit widths however.</p>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]4893<pre>
4894declare i8 @llvm.atomic.lcs.i8.i8p.i8.i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
4895declare i16 @llvm.atomic.lcs.i16.i16p.i16.i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
4896declare i32 @llvm.atomic.lcs.i32.i32p.i32.i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
4897declare i64 @llvm.atomic.lcs.i64.i64p.i64.i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
4898</pre>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]4899<h5>Overview:</h5>
4900<p>
Chandler Carruthfd4184352007-07-20 20:14:52 +0000[diff] [blame]4901 This loads a value in memory and compares it to a given value. If they are
4902 equal, it stores a new value into the memory.
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]4903</p>
4904<h5>Arguments:</h5>
4905<p>
4906 The <tt>llvm.atomic.lcs</tt> intrinsic takes three arguments. The result as
4907 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
4908 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
4909 this integer type. While any bit width integer may be used, targets may only
4910 lower representations they support in hardware.
4911</p>
4912<h5>Semantics:</h5>
4913<p>
4914 This entire intrinsic must be executed atomically. It first loads the value
Chandler Carruthfd4184352007-07-20 20:14:52 +0000[diff] [blame]4915 in memory pointed to by <tt>ptr</tt> and compares it with the value
4916 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
4917 loaded value is yielded in all cases. This provides the equivalent of an
4918 atomic compare-and-swap operation within the SSA framework.
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]4919</p>
4920<h5>Examples:</h5>
4921<pre>
4922%ptr = malloc i32
4923 store i32 4, %ptr
4924
4925%val1 = add i32 4, 4
4926%result1 = call i32 @llvm.atomic.lcs( i32* %ptr, i32 4, %val1 )
4927 <i>; yields {i32}:result1 = 4</i>
4928%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
4929%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
4930
4931%val2 = add i32 1, 1
4932%result2 = call i32 @llvm.atomic.lcs( i32* %ptr, i32 5, %val2 )
4933 <i>; yields {i32}:result2 = 8</i>
4934%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
4935%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
4936</pre>
4937</div>
4938
4939<!-- _______________________________________________________________________ -->
4940<div class="doc_subsubsection">
4941 <a name="int_ls">'<tt>llvm.atomic.ls.*</tt>' Intrinsic</a>
4942</div>
4943<div class="doc_text">
4944<h5>Syntax:</h5>
4945<p>
4946 This is an overloaded intrinsic. You can use <tt>llvm.atomic.ls</tt> on any
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]4947 integer bit width. Not all targets support all bit widths however.</p>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]4948<pre>
4949declare i8 @llvm.atomic.ls.i8.i8p.i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
4950declare i16 @llvm.atomic.ls.i16.i16p.i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
4951declare i32 @llvm.atomic.ls.i32.i32p.i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
4952declare i64 @llvm.atomic.ls.i64.i64p.i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
4953</pre>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]4954<h5>Overview:</h5>
4955<p>
Chandler Carruthfd4184352007-07-20 20:14:52 +0000[diff] [blame]4956 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
4957 the value from memory. It then stores the value in <tt>val</tt> in the memory
4958 at <tt>ptr</tt>.
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]4959</p>
4960<h5>Arguments:</h5>
4961<p>
4962 The <tt>llvm.atomic.ls</tt> intrinsic takes two arguments. Both the
4963 <tt>val</tt> argument and the result must be integers of the same bit width.
4964 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
4965 integer type. The targets may only lower integer representations they
4966 support.
4967</p>
4968<h5>Semantics:</h5>
4969<p>
4970 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
4971 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
4972 equivalent of an atomic swap operation within the SSA framework.
4973</p>
4974<h5>Examples:</h5>
4975<pre>
4976%ptr = malloc i32
4977 store i32 4, %ptr
4978
4979%val1 = add i32 4, 4
4980%result1 = call i32 @llvm.atomic.ls( i32* %ptr, i32 %val1 )
4981 <i>; yields {i32}:result1 = 4</i>
4982%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
4983%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
4984
4985%val2 = add i32 1, 1
4986%result2 = call i32 @llvm.atomic.ls( i32* %ptr, i32 %val2 )
4987 <i>; yields {i32}:result2 = 8</i>
4988%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
4989%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
4990</pre>
4991 </div>
4992
4993<!-- _______________________________________________________________________ -->
4994<div class="doc_subsubsection">
4995 <a name="int_las">'<tt>llvm.atomic.las.*</tt>' Intrinsic</a>
4996</div>
4997<div class="doc_text">
4998<h5>Syntax:</h5>
4999<p>
5000 This is an overloaded intrinsic. You can use <tt>llvm.atomic.las</tt> on any
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]5001 integer bit width. Not all targets support all bit widths however.</p>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]5002<pre>
5003declare i8 @llvm.atomic.las.i8.i8p.i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
5004declare i16 @llvm.atomic.las.i16.i16p.i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
5005declare i32 @llvm.atomic.las.i32.i32p.i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
5006declare i64 @llvm.atomic.las.i64.i64p.i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
5007</pre>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]5008<h5>Overview:</h5>
5009<p>
Chandler Carruthfd4184352007-07-20 20:14:52 +0000[diff] [blame]5010 This intrinsic adds <tt>delta</tt> to the value stored in memory at
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]5011 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
5012</p>
5013<h5>Arguments:</h5>
5014<p>
5015 The intrinsic takes two arguments, the first a pointer to an integer value
5016 and the second an integer value. The result is also an integer value. These
5017 integer types can have any bit width, but they must all have the same bit
5018 width. The targets may only lower integer representations they support.
5019</p>
5020<h5>Semantics:</h5>
5021<p>
5022 This intrinsic does a series of operations atomically. It first loads the
5023 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
5024 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
5025</p>
5026<h5>Examples:</h5>
5027<pre>
5028%ptr = malloc i32
5029 store i32 4, %ptr
5030%result1 = call i32 @llvm.atomic.las( i32* %ptr, i32 4 )
5031 <i>; yields {i32}:result1 = 4</i>
5032%result2 = call i32 @llvm.atomic.las( i32* %ptr, i32 2 )
5033 <i>; yields {i32}:result2 = 8</i>
5034%result3 = call i32 @llvm.atomic.las( i32* %ptr, i32 5 )
5035 <i>; yields {i32}:result3 = 10</i>
5036%memval = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
5037</pre>
5038</div>
5039
5040<!-- _______________________________________________________________________ -->
5041<div class="doc_subsubsection">
5042 <a name="int_lss">'<tt>llvm.atomic.lss.*</tt>' Intrinsic</a>
5043</div>
5044<div class="doc_text">
5045<h5>Syntax:</h5>
5046<p>
5047 This is an overloaded intrinsic. You can use <tt>llvm.atomic.lss</tt> on any
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]5048 integer bit width. Not all targets support all bit widths however.</p>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]5049<pre>
5050declare i8 @llvm.atomic.lss.i8.i8.i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
5051declare i16 @llvm.atomic.lss.i16.i16.i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
5052declare i32 @llvm.atomic.lss.i32.i32.i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
5053declare i64 @llvm.atomic.lss.i64.i64.i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
5054</pre>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]5055<h5>Overview:</h5>
5056<p>
Chandler Carruthfd4184352007-07-20 20:14:52 +0000[diff] [blame]5057 This intrinsic subtracts <tt>delta</tt> from the value stored in memory at
5058 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]5059</p>
5060<h5>Arguments:</h5>
5061<p>
5062 The intrinsic takes two arguments, the first a pointer to an integer value
5063 and the second an integer value. The result is also an integer value. These
5064 integer types can have any bit width, but they must all have the same bit
5065 width. The targets may only lower integer representations they support.
5066</p>
5067<h5>Semantics:</h5>
5068<p>
5069 This intrinsic does a series of operations atomically. It first loads the
5070 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>,
5071 stores the result to <tt>ptr</tt>. It yields the original value stored
5072 at <tt>ptr</tt>.
5073</p>
5074<h5>Examples:</h5>
5075<pre>
5076%ptr = malloc i32
5077 store i32 32, %ptr
5078%result1 = call i32 @llvm.atomic.lss( i32* %ptr, i32 4 )
5079 <i>; yields {i32}:result1 = 32</i>
5080%result2 = call i32 @llvm.atomic.lss( i32* %ptr, i32 2 )
5081 <i>; yields {i32}:result2 = 28</i>
5082%result3 = call i32 @llvm.atomic.lss( i32* %ptr, i32 5 )
5083 <i>; yields {i32}:result3 = 26</i>
5084%memval = load i32* %ptr <i>; yields {i32}:memval1 = 21</i>
5085</pre>
5086</div>
5087
5088<!-- _______________________________________________________________________ -->
5089<div class="doc_subsubsection">
5090 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5091</div>
5092<div class="doc_text">
5093<h5>Syntax:</h5>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]5094<pre>
5095declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt; )
5096</pre>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]5097<h5>Overview:</h5>
5098<p>
5099 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5100 specific pairs of memory access types.
5101</p>
5102<h5>Arguments:</h5>
5103<p>
5104 The <tt>llvm.memory.barrier</tt> intrinsic requires four boolean arguments.
5105 Each argument enables a specific barrier as listed below.
Reid Spencer65a72e32007-07-20 20:03:33 +0000[diff] [blame]5106</p>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]5107 <ul>
5108 <li><tt>ll</tt>: load-load barrier</li>
5109 <li><tt>ls</tt>: load-store barrier</li>
5110 <li><tt>sl</tt>: store-load barrier</li>
5111 <li><tt>ss</tt>: store-store barrier</li>
5112 </ul>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]5113<h5>Semantics:</h5>
5114<p>
5115 This intrinsic causes the system to enforce some ordering constraints upon
5116 the loads and stores of the program. This barrier does not indicate
5117 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5118 which they occur. For any of the specified pairs of load and store operations
5119 (f.ex. load-load, or store-load), all of the first operations preceding the
5120 barrier will complete before any of the second operations succeeding the
5121 barrier begin. Specifically the semantics for each pairing is as follows:
Reid Spencer65a72e32007-07-20 20:03:33 +0000[diff] [blame]5122</p>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]5123 <ul>
5124 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5125 after the barrier begins.</li>
5126 <li><tt>ls</tt>: All loads before the barrier must complete before any
5127 store after the barrier begins.</li>
5128 <li><tt>ss</tt>: All stores before the barrier must complete before any
5129 store after the barrier begins.</li>
5130 <li><tt>sl</tt>: All stores before the barrier must complete before any
5131 load after the barrier begins.</li>
5132 </ul>
Reid Spencer65a72e32007-07-20 20:03:33 +0000[diff] [blame]5133<p>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]5134 These semantics are applied with a logical "and" behavior when more than one
5135 is enabled in a single memory barrier intrinsic.
5136</p>
5137<h5>Example:</h5>
5138<pre>
5139%ptr = malloc i32
5140 store i32 4, %ptr
5141
5142%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
5143 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
5144 <i>; guarantee the above finishes</i>
5145 store i32 8, %ptr <i>; before this begins</i>
5146</pre>
5147</div>
5148
5149<!-- ======================================================================= -->
5150<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame^]5151 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5152</div>
5153
5154<div class="doc_text">
5155<p>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame^]5156 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5157 the <tt>nest</tt> attribute, from a function. The result is a callable
5158 function pointer lacking the nest parameter - the caller does not need
5159 to provide a value for it. Instead, the value to use is stored in
5160 advance in a "trampoline", a block of memory usually allocated
5161 on the stack, which also contains code to splice the nest value into the
5162 argument list. This is used to implement the GCC nested function address
5163 extension.
5164</p>
5165<p>
5166 For example, if the function is
5167 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
5168 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as follows:
5169<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame^]5170 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5171 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5172 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5173 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5174</pre>
5175 The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent to
5176 <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.
5177</p>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5178</div>
5179
5180<!-- _______________________________________________________________________ -->
5181<div class="doc_subsubsection">
5182 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5183</div>
5184<div class="doc_text">
5185<h5>Syntax:</h5>
5186<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame^]5187declare i8* @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5188</pre>
5189<h5>Overview:</h5>
5190<p>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame^]5191 This fills the memory pointed to by <tt>tramp</tt> with code
5192 and returns a function pointer suitable for executing it.
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5193</p>
5194<h5>Arguments:</h5>
5195<p>
5196 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5197 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5198 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sandsf2bcd372007-08-22 23:39:54 +0000[diff] [blame]5199 intrinsic. Note that the size and the alignment are target-specific - LLVM
5200 currently provides no portable way of determining them, so a front-end that
5201 generates this intrinsic needs to have some target-specific knowledge.
5202 The <tt>func</tt> argument must hold a function bitcast to an <tt>i8*</tt>.
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5203</p>
5204<h5>Semantics:</h5>
5205<p>
5206 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame^]5207 dependent code, turning it into a function. A pointer to this function is
5208 returned, but needs to be bitcast to an
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5209 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame^]5210 before being called. The new function's signature is the same as that of
5211 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5212 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5213 of pointer type. Calling the new function is equivalent to calling
5214 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5215 missing <tt>nest</tt> argument. If, after calling
5216 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5217 modified, then the effect of any later call to the returned function pointer is
5218 undefined.
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5219</p>
5220</div>
5221
5222<!-- ======================================================================= -->
5223<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5224 <a name="int_general">General Intrinsics</a>
5225</div>
5226
5227<div class="doc_text">
5228<p> This class of intrinsics is designed to be generic and has
5229no specific purpose. </p>
5230</div>
5231
5232<!-- _______________________________________________________________________ -->
5233<div class="doc_subsubsection">
5234 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
5235</div>
5236
5237<div class="doc_text">
5238
5239<h5>Syntax:</h5>
5240<pre>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]5241 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5242</pre>
5243
5244<h5>Overview:</h5>
5245
5246<p>
5247The '<tt>llvm.var.annotation</tt>' intrinsic
5248</p>
5249
5250<h5>Arguments:</h5>
5251
5252<p>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]5253The first argument is a pointer to a value, the second is a pointer to a
5254global string, the third is a pointer to a global string which is the source
5255file name, and the last argument is the line number.
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5256</p>
5257
5258<h5>Semantics:</h5>
5259
5260<p>
5261This intrinsic allows annotation of local variables with arbitrary strings.
5262This can be useful for special purpose optimizations that want to look for these
5263 annotations. These have no other defined use, they are ignored by code
5264 generation and optimization.
5265</div>
5266
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]5267
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5268<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5269<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]5270<address>
5271 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
5272 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
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5275
5276 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]5277 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]5278 Last modified: $Date$
5279</address>
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5281</html>