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gerrit-public.fairphone.software / platform / external / llvm / 85d5aaecd03ca4bc6e406ee88c72a4ba8878bb2b / . / 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">
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
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11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]15<h1>LLVM Language Reference Manual</h1>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 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 Lattnerfa730212004-12-09 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>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]28 <li><a href="#linkage_linker_private_weak_def_auto">'<tt>linker_private_weak_def_auto</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]29 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
30 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
31 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
32 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
33 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
34 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
35 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner5a2d8752009-10-10 18:26:06 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]37 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
Bill Wendlingf7f06102011-10-11 06:41:28 +0000[diff] [blame]38 <li><a href="#linkage_external">'<tt>external</tt>' Linkage</a></li>
Bill Wendling987e7eb2009-07-20 02:41:50 +0000[diff] [blame]39 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
40 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]41 </ol>
42 </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]43 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]44 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]45 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]46 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]47 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]48 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]49 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]50 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]51 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]52 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]53 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]54 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]55 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]56 <li><a href="#memmodel">Memory Model for Concurrent Operations</a></li>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]57 <li><a href="#ordering">Atomic Memory Ordering Constraints</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]58 </ol>
59 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]60 <li><a href="#typesystem">Type System</a>
61 <ol>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]62 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]63 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]64 <ol>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]65 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]66 <li><a href="#t_floating">Floating Point Types</a></li>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]67 <li><a href="#t_x86mmx">X86mmx Type</a></li>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]68 <li><a href="#t_void">Void Type</a></li>
69 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]70 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]71 </ol>
72 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]73 <li><a href="#t_derived">Derived Types</a>
74 <ol>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]75 <li><a href="#t_aggregate">Aggregate Types</a>
76 <ol>
77 <li><a href="#t_array">Array Type</a></li>
78 <li><a href="#t_struct">Structure Type</a></li>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]79 <li><a href="#t_opaque">Opaque Structure Types</a></li>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]80 <li><a href="#t_vector">Vector Type</a></li>
81 </ol>
82 </li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]83 <li><a href="#t_function">Function Type</a></li>
84 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]85 </ol>
86 </li>
87 </ol>
88 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]89 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]90 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]92 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
94 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]95 <li><a href="#poisonvalues">Poison Values</a></li>
Chris Lattnerf9d078e2009-10-27 21:19:13 +0000[diff] [blame]96 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]97 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]98 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]99 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]100 <li><a href="#othervalues">Other Values</a>
101 <ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]102 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]103 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a>
104 <ol>
105 <li><a href="#tbaa">'<tt>tbaa</tt>' Metadata</a></li>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]106 <li><a href="#fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a></li>
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]107 </ol>
108 </li>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]109 </ol>
110 </li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]111 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
112 <ol>
113 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]114 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
115 Global Variable</a></li>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]116 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
117 Global Variable</a></li>
118 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
119 Global Variable</a></li>
120 </ol>
121 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]122 <li><a href="#instref">Instruction Reference</a>
123 <ol>
124 <li><a href="#terminators">Terminator Instructions</a>
125 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]126 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
127 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]128 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]129 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]130 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]131 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]132 <li><a href="#i_resume">'<tt>resume</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]133 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]134 </ol>
135 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]136 <li><a href="#binaryops">Binary Operations</a>
137 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]138 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]139 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]140 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]141 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]142 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]143 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]144 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
145 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
146 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]147 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
148 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
149 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]150 </ol>
151 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]152 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
153 <ol>
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]154 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
155 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
156 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]157 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]158 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]159 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]160 </ol>
161 </li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]162 <li><a href="#vectorops">Vector Operations</a>
163 <ol>
164 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
165 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
166 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]167 </ol>
168 </li>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]169 <li><a href="#aggregateops">Aggregate Operations</a>
170 <ol>
171 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
172 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
173 </ol>
174 </li>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]175 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]176 <ol>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]177 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
178 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
179 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
180 <li><a href="#i_fence">'<tt>fence</tt>' Instruction</a></li>
181 <li><a href="#i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a></li>
182 <li><a href="#i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a></li>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]183 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]184 </ol>
185 </li>
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]186 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]187 <ol>
188 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
189 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
190 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
191 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
192 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]193 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
194 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
195 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
196 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]197 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
198 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]199 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]200 </ol>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]201 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]202 <li><a href="#otherops">Other Operations</a>
203 <ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]204 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
205 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]206 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]207 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]208 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]209 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]210 <li><a href="#i_landingpad">'<tt>landingpad</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]211 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]212 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]213 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]214 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]215 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]216 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]217 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
218 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]219 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
220 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
221 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]222 </ol>
223 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]224 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
225 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]226 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
227 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
228 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]229 </ol>
230 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]231 <li><a href="#int_codegen">Code Generator Intrinsics</a>
232 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]233 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
234 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
235 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
236 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
237 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
238 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohman31f1af12010-05-26 21:56:15 +0000[diff] [blame]239 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]240 </ol>
241 </li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]242 <li><a href="#int_libc">Standard C Library Intrinsics</a>
243 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]244 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
245 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
246 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
247 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
248 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]249 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
250 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
251 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohman08b280b2011-05-27 00:36:31 +0000[diff] [blame]252 <li><a href="#int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a></li>
253 <li><a href="#int_log">'<tt>llvm.log.*</tt>' Intrinsic</a></li>
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]254 <li><a href="#int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]255 </ol>
256 </li>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]257 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]258 <ol>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]259 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]260 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
261 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
262 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]263 </ol>
264 </li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]265 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
266 <ol>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]267 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
268 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
269 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
270 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
271 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]272 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]273 </ol>
274 </li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]275 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
276 <ol>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]277 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
278 <li><a href="#int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a></li>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]279 </ol>
280 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]281 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]282 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]283 <li><a href="#int_trampoline">Trampoline Intrinsics</a>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]284 <ol>
285 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]286 <li><a href="#int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a></li>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]287 </ol>
288 </li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]289 <li><a href="#int_memorymarkers">Memory Use Markers</a>
290 <ol>
Jakub Staszak8e1b12a2011-12-04 20:44:25 +0000[diff] [blame]291 <li><a href="#int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a></li>
292 <li><a href="#int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a></li>
293 <li><a href="#int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a></li>
294 <li><a href="#int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a></li>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]295 </ol>
296 </li>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]297 <li><a href="#int_general">General intrinsics</a>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]298 <ol>
Reid Spencer20677642007-07-20 19:59:11 +0000[diff] [blame]299 <li><a href="#int_var_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]300 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]301 <li><a href="#int_annotation">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]302 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]303 <li><a href="#int_trap">
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]304 '<tt>llvm.trap</tt>' Intrinsic</a></li>
305 <li><a href="#int_stackprotector">
306 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]307 <li><a href="#int_objectsize">
308 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]309 <li><a href="#int_expect">
310 '<tt>llvm.expect</tt>' Intrinsic</a></li>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]311 </ol>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]312 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]313 </ol>
314 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]315</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]316
317<div class="doc_author">
318 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
319 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]320</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]321
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]322<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]323<h2><a name="abstract">Abstract</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]324<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]325
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]326<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]327
328<p>This document is a reference manual for the LLVM assembly language. LLVM is
329 a Static Single Assignment (SSA) based representation that provides type
330 safety, low-level operations, flexibility, and the capability of representing
331 'all' high-level languages cleanly. It is the common code representation
332 used throughout all phases of the LLVM compilation strategy.</p>
333
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]334</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]335
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]336<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]337<h2><a name="introduction">Introduction</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]338<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]339
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]340<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]341
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]342<p>The LLVM code representation is designed to be used in three different forms:
343 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
344 for fast loading by a Just-In-Time compiler), and as a human readable
345 assembly language representation. This allows LLVM to provide a powerful
346 intermediate representation for efficient compiler transformations and
347 analysis, while providing a natural means to debug and visualize the
348 transformations. The three different forms of LLVM are all equivalent. This
349 document describes the human readable representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]350
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]351<p>The LLVM representation aims to be light-weight and low-level while being
352 expressive, typed, and extensible at the same time. It aims to be a
353 "universal IR" of sorts, by being at a low enough level that high-level ideas
354 may be cleanly mapped to it (similar to how microprocessors are "universal
355 IR's", allowing many source languages to be mapped to them). By providing
356 type information, LLVM can be used as the target of optimizations: for
357 example, through pointer analysis, it can be proven that a C automatic
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]358 variable is never accessed outside of the current function, allowing it to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]359 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]360
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]361<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]362<h4>
363 <a name="wellformed">Well-Formedness</a>
364</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]365
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]366<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]367
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]368<p>It is important to note that this document describes 'well formed' LLVM
369 assembly language. There is a difference between what the parser accepts and
370 what is considered 'well formed'. For example, the following instruction is
371 syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]372
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]373<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]374%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]375</pre>
376
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]377<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
378 LLVM infrastructure provides a verification pass that may be used to verify
379 that an LLVM module is well formed. This pass is automatically run by the
380 parser after parsing input assembly and by the optimizer before it outputs
381 bitcode. The violations pointed out by the verifier pass indicate bugs in
382 transformation passes or input to the parser.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]383
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]384</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]385
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]386</div>
387
Chris Lattnercc689392007-10-03 17:34:29 +0000[diff] [blame]388<!-- Describe the typesetting conventions here. -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]389
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]390<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]391<h2><a name="identifiers">Identifiers</a></h2>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]392<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]393
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]394<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]395
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]396<p>LLVM identifiers come in two basic types: global and local. Global
397 identifiers (functions, global variables) begin with the <tt>'@'</tt>
398 character. Local identifiers (register names, types) begin with
399 the <tt>'%'</tt> character. Additionally, there are three different formats
400 for identifiers, for different purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]401
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]402<ol>
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]403 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]404 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
405 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
406 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
407 other characters in their names can be surrounded with quotes. Special
408 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
409 ASCII code for the character in hexadecimal. In this way, any character
410 can be used in a name value, even quotes themselves.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]411
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]412 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]413 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]414
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]415 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]416 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]417</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]418
Reid Spencer2c452282007-08-07 14:34:28 +0000[diff] [blame]419<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]420 don't need to worry about name clashes with reserved words, and the set of
421 reserved words may be expanded in the future without penalty. Additionally,
422 unnamed identifiers allow a compiler to quickly come up with a temporary
423 variable without having to avoid symbol table conflicts.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]424
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]425<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]426 languages. There are keywords for different opcodes
427 ('<tt><a href="#i_add">add</a></tt>',
428 '<tt><a href="#i_bitcast">bitcast</a></tt>',
429 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
430 ('<tt><a href="#t_void">void</a></tt>',
431 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
432 reserved words cannot conflict with variable names, because none of them
433 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]434
435<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]436 '<tt>%X</tt>' by 8:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]437
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]438<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]439
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]440<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]441%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]442</pre>
443
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]444<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]445
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]446<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]447%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]448</pre>
449
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]450<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]451
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]452<pre class="doc_code">
Gabor Greifec58f752009-10-28 13:05:07 +0000[diff] [blame]453%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
454%1 = <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]455%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]456</pre>
457
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]458<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
459 lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]460
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]461<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]462 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]463 line.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]464
465 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]466 assigned to a named value.</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]467
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]468 <li>Unnamed temporaries are numbered sequentially</li>
469</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]470
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]471<p>It also shows a convention that we follow in this document. When
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]472 demonstrating instructions, we will follow an instruction with a comment that
473 defines the type and name of value produced. Comments are shown in italic
474 text.</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]475
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]476</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]477
478<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]479<h2><a name="highlevel">High Level Structure</a></h2>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]480<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]481<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]482<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]483<h3>
484 <a name="modulestructure">Module Structure</a>
485</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]486
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]487<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]488
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]489<p>LLVM programs are composed of "Module"s, each of which is a translation unit
490 of the input programs. Each module consists of functions, global variables,
491 and symbol table entries. Modules may be combined together with the LLVM
492 linker, which merges function (and global variable) definitions, resolves
493 forward declarations, and merges symbol table entries. Here is an example of
494 the "hello world" module:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]495
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]496<pre class="doc_code">
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]497<i>; Declare the string constant as a global constant.</i>&nbsp;
Nick Lewyckydb9cd762011-01-29 01:09:53 +0000[diff] [blame]498<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a>&nbsp;<a href="#globalvars">constant</a>&nbsp;<a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]499
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]500<i>; External declaration of the puts function</i>&nbsp;
501<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]502
503<i>; Definition of main function</i>
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]504define i32 @main() { <i>; i32()* </i>&nbsp;
505 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
506 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8*</i>&nbsp;
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]507
Chris Lattner63e4ccb2010-08-17 17:13:42 +0000[diff] [blame]508 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
509 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
510 <a href="#i_ret">ret</a> i32 0&nbsp;
511}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]512
513<i>; Named metadata</i>
514!1 = metadata !{i32 41}
515!foo = !{!1, null}
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]516</pre>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]517
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]518<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]519 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]520 a <a href="#functionstructure">function definition</a> for
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]521 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
522 "<tt>foo"</tt>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]523
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]524<p>In general, a module is made up of a list of global values, where both
525 functions and global variables are global values. Global values are
526 represented by a pointer to a memory location (in this case, a pointer to an
527 array of char, and a pointer to a function), and have one of the
528 following <a href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]529
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]530</div>
531
532<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]533<h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]534 <a name="linkage">Linkage Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]535</h3>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]536
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]537<div>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]538
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]539<p>All Global Variables and Functions have one of the following types of
540 linkage:</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]541
542<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]543 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]544 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
545 by objects in the current module. In particular, linking code into a
546 module with an private global value may cause the private to be renamed as
547 necessary to avoid collisions. Because the symbol is private to the
548 module, all references can be updated. This doesn't show up in any symbol
549 table in the object file.</dd>
Rafael Espindolabb46f522009-01-15 20:18:42 +0000[diff] [blame]550
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]551 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]552 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
553 assembler and evaluated by the linker. Unlike normal strong symbols, they
554 are removed by the linker from the final linked image (executable or
555 dynamic library).</dd>
556
557 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
558 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
559 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
560 linker. The symbols are removed by the linker from the final linked image
561 (executable or dynamic library).</dd>
Bill Wendling3d10a5a2009-07-20 01:03:30 +0000[diff] [blame]562
Bill Wendling55ae5152010-08-20 22:05:50 +0000[diff] [blame]563 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
564 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
565 of the object is not taken. For instance, functions that had an inline
566 definition, but the compiler decided not to inline it. Note,
567 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
568 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
569 visibility. The symbols are removed by the linker from the final linked
570 image (executable or dynamic library).</dd>
571
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]572 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling07d31772010-06-29 22:34:52 +0000[diff] [blame]573 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]574 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
575 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]576
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]577 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]578 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]579 into the object file corresponding to the LLVM module. They exist to
580 allow inlining and other optimizations to take place given knowledge of
581 the definition of the global, which is known to be somewhere outside the
582 module. Globals with <tt>available_externally</tt> linkage are allowed to
583 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
584 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner266c7bb2009-04-13 05:44:34 +0000[diff] [blame]585
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]586 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattner4887bd82007-01-14 06:51:48 +0000[diff] [blame]587 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner873187c2010-01-09 19:15:14 +0000[diff] [blame]588 the same name when linkage occurs. This can be used to implement
589 some forms of inline functions, templates, or other code which must be
590 generated in each translation unit that uses it, but where the body may
591 be overridden with a more definitive definition later. Unreferenced
592 <tt>linkonce</tt> globals are allowed to be discarded. Note that
593 <tt>linkonce</tt> linkage does not actually allow the optimizer to
594 inline the body of this function into callers because it doesn't know if
595 this definition of the function is the definitive definition within the
596 program or whether it will be overridden by a stronger definition.
597 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
598 linkage.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]599
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]600 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]601 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
602 <tt>linkonce</tt> linkage, except that unreferenced globals with
603 <tt>weak</tt> linkage may not be discarded. This is used for globals that
604 are declared "weak" in C source code.</dd>
605
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]606 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]607 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
608 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
609 global scope.
610 Symbols with "<tt>common</tt>" linkage are merged in the same way as
611 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]612 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]613 must have a zero initializer, and may not be marked '<a
Chris Lattnercd81f5d2009-08-05 05:41:44 +0000[diff] [blame]614 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
615 have common linkage.</dd>
Chris Lattner26d054d2009-08-05 05:21:07 +0000[diff] [blame]616
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]617
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]618 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]619 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]620 pointer to array type. When two global variables with appending linkage
621 are linked together, the two global arrays are appended together. This is
622 the LLVM, typesafe, equivalent of having the system linker append together
623 "sections" with identical names when .o files are linked.</dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]624
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]625 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]626 <dd>The semantics of this linkage follow the ELF object file model: the symbol
627 is weak until linked, if not linked, the symbol becomes null instead of
628 being an undefined reference.</dd>
Anton Korobeynikov7f705592007-01-12 19:20:47 +0000[diff] [blame]629
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]630 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
631 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]632 <dd>Some languages allow differing globals to be merged, such as two functions
633 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling5e721d72010-07-01 21:55:59 +0000[diff] [blame]634 that only equivalent globals are ever merged (the "one definition rule"
635 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]636 and <tt>weak_odr</tt> linkage types to indicate that the global will only
637 be merged with equivalent globals. These linkage types are otherwise the
638 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]639
Bill Wendling5c3a9f72011-11-04 20:40:41 +0000[diff] [blame]640 <dt><tt><b><a name="linkage_external">external</a></b></tt></dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]641 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]642 visible, meaning that it participates in linkage and can be used to
643 resolve external symbol references.</dd>
Reid Spencerc8910842007-04-11 23:49:50 +0000[diff] [blame]644</dl>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]645
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]646<p>The next two types of linkage are targeted for Microsoft Windows platform
647 only. They are designed to support importing (exporting) symbols from (to)
648 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]649
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]650<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]651 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]652 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]653 or variable via a global pointer to a pointer that is set up by the DLL
654 exporting the symbol. On Microsoft Windows targets, the pointer name is
655 formed by combining <code>__imp_</code> and the function or variable
656 name.</dd>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]657
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]658 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovb74ed072006-09-14 18:23:27 +0000[diff] [blame]659 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]660 pointer to a pointer in a DLL, so that it can be referenced with the
661 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
662 name is formed by combining <code>__imp_</code> and the function or
663 variable name.</dd>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]664</dl>
665
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]666<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
667 another module defined a "<tt>.LC0</tt>" variable and was linked with this
668 one, one of the two would be renamed, preventing a collision. Since
669 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
670 declarations), they are accessible outside of the current module.</p>
671
672<p>It is illegal for a function <i>declaration</i> to have any linkage type
Bill Wendlingf7f06102011-10-11 06:41:28 +0000[diff] [blame]673 other than <tt>external</tt>, <tt>dllimport</tt>
674 or <tt>extern_weak</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]675
Duncan Sands667d4b82009-03-07 15:45:40 +0000[diff] [blame]676<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]677 or <tt>weak_odr</tt> linkages.</p>
678
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]679</div>
680
681<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]682<h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]683 <a name="callingconv">Calling Conventions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]684</h3>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]685
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]686<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]687
688<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]689 and <a href="#i_invoke">invokes</a> can all have an optional calling
690 convention specified for the call. The calling convention of any pair of
691 dynamic caller/callee must match, or the behavior of the program is
692 undefined. The following calling conventions are supported by LLVM, and more
693 may be added in the future:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]694
695<dl>
696 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]697 <dd>This calling convention (the default if no other calling convention is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]698 specified) matches the target C calling conventions. This calling
699 convention supports varargs function calls and tolerates some mismatch in
700 the declared prototype and implemented declaration of the function (as
701 does normal C).</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]702
703 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]704 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]705 (e.g. by passing things in registers). This calling convention allows the
706 target to use whatever tricks it wants to produce fast code for the
707 target, without having to conform to an externally specified ABI
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]708 (Application Binary Interface).
709 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]710 when this or the GHC convention is used.</a> This calling convention
711 does not support varargs and requires the prototype of all callees to
712 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]713
714 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]715 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]716 as possible under the assumption that the call is not commonly executed.
717 As such, these calls often preserve all registers so that the call does
718 not break any live ranges in the caller side. This calling convention
719 does not support varargs and requires the prototype of all callees to
720 exactly match the prototype of the function definition.</dd>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]721
Chris Lattner29689432010-03-11 00:22:57 +0000[diff] [blame]722 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
723 <dd>This calling convention has been implemented specifically for use by the
724 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
725 It passes everything in registers, going to extremes to achieve this by
726 disabling callee save registers. This calling convention should not be
727 used lightly but only for specific situations such as an alternative to
728 the <em>register pinning</em> performance technique often used when
729 implementing functional programming languages.At the moment only X86
730 supports this convention and it has the following limitations:
731 <ul>
732 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
733 floating point types are supported.</li>
734 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
735 6 floating point parameters.</li>
736 </ul>
737 This calling convention supports
738 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
739 requires both the caller and callee are using it.
740 </dd>
741
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]742 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]743 <dd>Any calling convention may be specified by number, allowing
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]744 target-specific calling conventions to be used. Target specific calling
745 conventions start at 64.</dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame]746</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]747
748<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]749 support Pascal conventions or any other well-known target-independent
750 convention.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]751
752</div>
753
754<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]755<h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]756 <a name="visibility">Visibility Styles</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]757</h3>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]758
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]759<div>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]760
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]761<p>All Global Variables and Functions have one of the following visibility
762 styles:</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]763
764<dl>
765 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]766 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]767 that the declaration is visible to other modules and, in shared libraries,
768 means that the declared entity may be overridden. On Darwin, default
769 visibility means that the declaration is visible to other modules. Default
770 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]771
772 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]773 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]774 object if they are in the same shared object. Usually, hidden visibility
775 indicates that the symbol will not be placed into the dynamic symbol
776 table, so no other module (executable or shared library) can reference it
777 directly.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]778
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]779 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov6f9896f2007-04-29 18:35:00 +0000[diff] [blame]780 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]781 the dynamic symbol table, but that references within the defining module
782 will bind to the local symbol. That is, the symbol cannot be overridden by
783 another module.</dd>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]784</dl>
785
786</div>
787
788<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]789<h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]790 <a name="namedtypes">Named Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]791</h3>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]792
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]793<div>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]794
795<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]796 it easier to read the IR and make the IR more condensed (particularly when
797 recursive types are involved). An example of a name specification is:</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]798
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]799<pre class="doc_code">
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]800%mytype = type { %mytype*, i32 }
801</pre>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]802
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]803<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattnerdc65f222010-08-17 23:26:04 +0000[diff] [blame]804 "<a href="#t_void">void</a>". Type name aliases may be used anywhere a type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]805 is expected with the syntax "%mytype".</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]806
807<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]808 and that you can therefore specify multiple names for the same type. This
809 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
810 uses structural typing, the name is not part of the type. When printing out
811 LLVM IR, the printer will pick <em>one name</em> to render all types of a
812 particular shape. This means that if you have code where two different
813 source types end up having the same LLVM type, that the dumper will sometimes
814 print the "wrong" or unexpected type. This is an important design point and
815 isn't going to change.</p>
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]816
817</div>
818
Chris Lattnere7886e42009-01-11 20:53:49 +0000[diff] [blame]819<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]820<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]821 <a name="globalvars">Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]822</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]823
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]824<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]825
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]826<p>Global variables define regions of memory allocated at compilation time
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]827 instead of run-time. Global variables may optionally be initialized, may
828 have an explicit section to be placed in, and may have an optional explicit
829 alignment specified. A variable may be defined as "thread_local", which
830 means that it will not be shared by threads (each thread will have a
831 separated copy of the variable). A variable may be defined as a global
832 "constant," which indicates that the contents of the variable
833 will <b>never</b> be modified (enabling better optimization, allowing the
834 global data to be placed in the read-only section of an executable, etc).
835 Note that variables that need runtime initialization cannot be marked
836 "constant" as there is a store to the variable.</p>
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]837
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]838<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
839 constant, even if the final definition of the global is not. This capability
840 can be used to enable slightly better optimization of the program, but
841 requires the language definition to guarantee that optimizations based on the
842 'constantness' are valid for the translation units that do not include the
843 definition.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]844
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]845<p>As SSA values, global variables define pointer values that are in scope
846 (i.e. they dominate) all basic blocks in the program. Global variables
847 always define a pointer to their "content" type because they describe a
848 region of memory, and all memory objects in LLVM are accessed through
849 pointers.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]850
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]851<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
852 that the address is not significant, only the content. Constants marked
Rafael Espindolaa5eaa862011-01-15 08:20:57 +0000[diff] [blame]853 like this can be merged with other constants if they have the same
854 initializer. Note that a constant with significant address <em>can</em>
855 be merged with a <tt>unnamed_addr</tt> constant, the result being a
856 constant whose address is significant.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]857
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]858<p>A global variable may be declared to reside in a target-specific numbered
859 address space. For targets that support them, address spaces may affect how
860 optimizations are performed and/or what target instructions are used to
861 access the variable. The default address space is zero. The address space
862 qualifier must precede any other attributes.</p>
Christopher Lamb284d9922007-12-11 09:31:00 +0000[diff] [blame]863
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]864<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]865 supports it, it will emit globals to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]866
Chris Lattnerce99fa92010-04-28 00:13:42 +0000[diff] [blame]867<p>An explicit alignment may be specified for a global, which must be a power
868 of 2. If not present, or if the alignment is set to zero, the alignment of
869 the global is set by the target to whatever it feels convenient. If an
870 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner2d4b8ee2010-04-28 00:31:12 +0000[diff] [blame]871 alignment. Targets and optimizers are not allowed to over-align the global
872 if the global has an assigned section. In this case, the extra alignment
873 could be observable: for example, code could assume that the globals are
874 densely packed in their section and try to iterate over them as an array,
875 alignment padding would break this iteration.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]876
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]877<p>For example, the following defines a global in a numbered address space with
878 an initializer, section, and alignment:</p>
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]879
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]880<pre class="doc_code">
Dan Gohman398873c2009-01-11 00:40:00 +0000[diff] [blame]881@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner68027ea2007-01-14 00:27:09 +0000[diff] [blame]882</pre>
883
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]884</div>
885
886
887<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]888<h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]889 <a name="functionstructure">Functions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]890</h3>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]891
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]892<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]893
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]894<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]895 optional <a href="#linkage">linkage type</a>, an optional
896 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]897 <a href="#callingconv">calling convention</a>,
898 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]899 <a href="#paramattrs">parameter attribute</a> for the return type, a function
900 name, a (possibly empty) argument list (each with optional
901 <a href="#paramattrs">parameter attributes</a>), optional
902 <a href="#fnattrs">function attributes</a>, an optional section, an optional
903 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
904 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000[diff] [blame]905
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]906<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
907 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]908 <a href="#visibility">visibility style</a>, an optional
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]909 <a href="#callingconv">calling convention</a>,
910 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]911 <a href="#paramattrs">parameter attribute</a> for the return type, a function
912 name, a possibly empty list of arguments, an optional alignment, and an
913 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]914
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]915<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]916 (Control Flow Graph) for the function. Each basic block may optionally start
917 with a label (giving the basic block a symbol table entry), contains a list
918 of instructions, and ends with a <a href="#terminators">terminator</a>
919 instruction (such as a branch or function return).</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]920
Chris Lattner4a3c9012007-06-08 16:52:14 +0000[diff] [blame]921<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]922 executed on entrance to the function, and it is not allowed to have
923 predecessor basic blocks (i.e. there can not be any branches to the entry
924 block of a function). Because the block can have no predecessors, it also
925 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]926
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]927<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]928 supports it, it will emit functions to the section specified.</p>
Chris Lattner88f6c462005-11-12 00:45:07 +0000[diff] [blame]929
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]930<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]931 the alignment is set to zero, the alignment of the function is set by the
932 target to whatever it feels convenient. If an explicit alignment is
933 specified, the function is forced to have at least that much alignment. All
934 alignments must be a power of 2.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]935
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]936<p>If the <tt>unnamed_addr</tt> attribute is given, the address is know to not
Bill Wendling5c3a9f72011-11-04 20:40:41 +0000[diff] [blame]937 be significant and two identical functions can be merged.</p>
Rafael Espindolabea46262011-01-08 16:42:36 +0000[diff] [blame]938
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]939<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]940<pre class="doc_code">
Chris Lattner50ad45c2008-10-13 16:55:18 +0000[diff] [blame]941define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]942 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
943 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
944 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
945 [<a href="#gc">gc</a>] { ... }
946</pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]947
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]948</div>
949
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]950<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]951<h3>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]952 <a name="aliasstructure">Aliases</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]953</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]954
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]955<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]956
957<p>Aliases act as "second name" for the aliasee value (which can be either
958 function, global variable, another alias or bitcast of global value). Aliases
959 may have an optional <a href="#linkage">linkage type</a>, and an
960 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]961
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]962<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]963<pre class="doc_code">
Duncan Sands0b23ac12008-09-12 20:48:21 +0000[diff] [blame]964@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]965</pre>
Anton Korobeynikov8b0a8c82007-04-25 14:27:10 +0000[diff] [blame]966
967</div>
968
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]969<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]970<h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]971 <a name="namedmetadatastructure">Named Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]972</h3>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]973
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]974<div>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]975
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]976<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]977 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]978 a named metadata.</p>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]979
980<h5>Syntax:</h5>
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]981<pre class="doc_code">
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]982; Some unnamed metadata nodes, which are referenced by the named metadata.
983!0 = metadata !{metadata !"zero"}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]984!1 = metadata !{metadata !"one"}
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]985!2 = metadata !{metadata !"two"}
Dan Gohman1005bc52010-07-13 19:48:13 +0000[diff] [blame]986; A named metadata.
Dan Gohman872814a2010-07-21 18:54:18 +0000[diff] [blame]987!name = !{!0, !1, !2}
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]988</pre>
Devang Patelcd1fd252010-01-11 19:35:55 +0000[diff] [blame]989
990</div>
991
992<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]993<h3>
994 <a name="paramattrs">Parameter Attributes</a>
995</h3>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]996
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]997<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]998
999<p>The return type and each parameter of a function type may have a set of
1000 <i>parameter attributes</i> associated with them. Parameter attributes are
1001 used to communicate additional information about the result or parameters of
1002 a function. Parameter attributes are considered to be part of the function,
1003 not of the function type, so functions with different parameter attributes
1004 can have the same function type.</p>
1005
1006<p>Parameter attributes are simple keywords that follow the type specified. If
1007 multiple parameter attributes are needed, they are space separated. For
1008 example:</p>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1009
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1010<pre class="doc_code">
Nick Lewyckyb6a7d252009-02-15 23:06:14 +0000[diff] [blame]1011declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner66d922c2008-10-04 18:33:34 +0000[diff] [blame]1012declare i32 @atoi(i8 zeroext)
1013declare signext i8 @returns_signed_char()
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1014</pre>
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1015
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1016<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1017 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1018
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1019<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1020
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1021<dl>
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1022 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1023 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichebe81732011-03-16 22:20:18 +0000[diff] [blame]1024 should be zero-extended to the extent required by the target's ABI (which
1025 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1026 parameter) or the callee (for a return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1027
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1028 <dt><tt><b>signext</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1029 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich9e69ff92011-03-17 14:21:58 +0000[diff] [blame]1030 should be sign-extended to the extent required by the target's ABI (which
1031 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1032 return value).</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1033
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1034 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1035 <dd>This indicates that this parameter or return value should be treated in a
1036 special target-dependent fashion during while emitting code for a function
1037 call or return (usually, by putting it in a register as opposed to memory,
1038 though some targets use it to distinguish between two different kinds of
1039 registers). Use of this attribute is target-specific.</dd>
Chris Lattner47507de2008-01-11 06:20:47 +0000[diff] [blame]1040
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1041 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1042 <dd><p>This indicates that the pointer parameter should really be passed by
1043 value to the function. The attribute implies that a hidden copy of the
1044 pointee
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1045 is made between the caller and the callee, so the callee is unable to
1046 modify the value in the callee. This attribute is only valid on LLVM
1047 pointer arguments. It is generally used to pass structs and arrays by
1048 value, but is also valid on pointers to scalars. The copy is considered
1049 to belong to the caller not the callee (for example,
1050 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1051 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnera6fd81d2010-11-20 23:49:06 +0000[diff] [blame]1052 values.</p>
1053
1054 <p>The byval attribute also supports specifying an alignment with
1055 the align attribute. It indicates the alignment of the stack slot to
1056 form and the known alignment of the pointer specified to the call site. If
1057 the alignment is not specified, then the code generator makes a
1058 target-specific assumption.</p></dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1059
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1060 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1061 <dd>This indicates that the pointer parameter specifies the address of a
1062 structure that is the return value of the function in the source program.
1063 This pointer must be guaranteed by the caller to be valid: loads and
1064 stores to the structure may be assumed by the callee to not to trap. This
1065 may only be applied to the first parameter. This is not a valid attribute
1066 for return values. </dd>
1067
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1068 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1069 <dd>This indicates that pointer values
1070 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmanefca7f92010-07-02 23:46:54 +0000[diff] [blame]1071 value do not alias pointer values which are not <i>based</i> on it,
1072 ignoring certain "irrelevant" dependencies.
1073 For a call to the parent function, dependencies between memory
1074 references from before or after the call and from those during the call
1075 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1076 return value used in that call.
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1077 The caller shares the responsibility with the callee for ensuring that
1078 these requirements are met.
1079 For further details, please see the discussion of the NoAlias response in
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1080 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1081<br>
John McCall191d4ee2010-07-06 21:07:14 +0000[diff] [blame]1082 Note that this definition of <tt>noalias</tt> is intentionally
1083 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner211244a2010-07-06 20:51:35 +0000[diff] [blame]1084 arguments, though it is slightly weaker.
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]1085<br>
1086 For function return values, C99's <tt>restrict</tt> is not meaningful,
1087 while LLVM's <tt>noalias</tt> is.
1088 </dd>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1089
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1090 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1091 <dd>This indicates that the callee does not make any copies of the pointer
1092 that outlive the callee itself. This is not a valid attribute for return
1093 values.</dd>
1094
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]1095 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1096 <dd>This indicates that the pointer parameter can be excised using the
1097 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1098 attribute for return values.</dd>
1099</dl>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1100
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1101</div>
1102
1103<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1104<h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1105 <a name="gc">Garbage Collector Names</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1106</h3>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1107
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1108<div>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1109
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1110<p>Each function may specify a garbage collector name, which is simply a
1111 string:</p>
1112
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1113<pre class="doc_code">
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1114define void @f() gc "name" { ... }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1115</pre>
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1116
1117<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1118 collector which will cause the compiler to alter its output in order to
1119 support the named garbage collection algorithm.</p>
1120
Gordon Henriksen80a75bf2007-12-10 03:18:06 +0000[diff] [blame]1121</div>
1122
1123<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1124<h3>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1125 <a name="fnattrs">Function Attributes</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1126</h3>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1127
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1128<div>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1129
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1130<p>Function attributes are set to communicate additional information about a
1131 function. Function attributes are considered to be part of the function, not
1132 of the function type, so functions with different parameter attributes can
1133 have the same function type.</p>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1134
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1135<p>Function attributes are simple keywords that follow the type specified. If
1136 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1137
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1138<pre class="doc_code">
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1139define void @f() noinline { ... }
1140define void @f() alwaysinline { ... }
1141define void @f() alwaysinline optsize { ... }
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1142define void @f() optsize { ... }
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1143</pre>
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1144
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1145<dl>
Charles Davis1e063d12010-02-12 00:31:15 +0000[diff] [blame]1146 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1147 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1148 the backend should forcibly align the stack pointer. Specify the
1149 desired alignment, which must be a power of two, in parentheses.
1150
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1151 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1152 <dd>This attribute indicates that the inliner should attempt to inline this
1153 function into callers whenever possible, ignoring any active inlining size
1154 threshold for this caller.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1155
Dan Gohman129bd562011-06-16 16:03:13 +0000[diff] [blame]1156 <dt><tt><b>nonlazybind</b></tt></dt>
1157 <dd>This attribute suppresses lazy symbol binding for the function. This
1158 may make calls to the function faster, at the cost of extra program
1159 startup time if the function is not called during program startup.</dd>
1160
Jakob Stoklund Olesen570a4a52010-02-06 01:16:28 +0000[diff] [blame]1161 <dt><tt><b>inlinehint</b></tt></dt>
1162 <dd>This attribute indicates that the source code contained a hint that inlining
1163 this function is desirable (such as the "inline" keyword in C/C++). It
1164 is just a hint; it imposes no requirements on the inliner.</dd>
1165
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1166 <dt><tt><b>naked</b></tt></dt>
1167 <dd>This attribute disables prologue / epilogue emission for the function.
1168 This can have very system-specific consequences.</dd>
1169
1170 <dt><tt><b>noimplicitfloat</b></tt></dt>
1171 <dd>This attributes disables implicit floating point instructions.</dd>
1172
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1173 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1174 <dd>This attribute indicates that the inliner should never inline this
1175 function in any situation. This attribute may not be used together with
1176 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1177
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1178 <dt><tt><b>noredzone</b></tt></dt>
1179 <dd>This attribute indicates that the code generator should not use a red
1180 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel2c9c3e72008-09-26 23:51:19 +0000[diff] [blame]1181
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1182 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1183 <dd>This function attribute indicates that the function never returns
1184 normally. This produces undefined behavior at runtime if the function
1185 ever does dynamically return.</dd>
Bill Wendling31359ba2008-11-13 01:02:51 +0000[diff] [blame]1186
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1187 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1188 <dd>This function attribute indicates that the function never returns with an
1189 unwind or exceptional control flow. If the function does unwind, its
1190 runtime behavior is undefined.</dd>
Bill Wendlingfbaa7ed2008-11-26 19:07:40 +0000[diff] [blame]1191
Nick Lewycky76ec37a2010-07-06 18:24:09 +0000[diff] [blame]1192 <dt><tt><b>optsize</b></tt></dt>
1193 <dd>This attribute suggests that optimization passes and code generator passes
1194 make choices that keep the code size of this function low, and otherwise
1195 do optimizations specifically to reduce code size.</dd>
1196
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1197 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1198 <dd>This attribute indicates that the function computes its result (or decides
1199 to unwind an exception) based strictly on its arguments, without
1200 dereferencing any pointer arguments or otherwise accessing any mutable
1201 state (e.g. memory, control registers, etc) visible to caller functions.
1202 It does not write through any pointer arguments
1203 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1204 changes any state visible to callers. This means that it cannot unwind
1205 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1206 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel5d96fda2009-06-12 19:45:19 +0000[diff] [blame]1207
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1208 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1209 <dd>This attribute indicates that the function does not write through any
1210 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1211 arguments) or otherwise modify any state (e.g. memory, control registers,
1212 etc) visible to caller functions. It may dereference pointer arguments
1213 and read state that may be set in the caller. A readonly function always
1214 returns the same value (or unwinds an exception identically) when called
1215 with the same set of arguments and global state. It cannot unwind an
1216 exception by calling the <tt>C++</tt> exception throwing methods, but may
1217 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc5ec8a72009-07-17 18:07:26 +0000[diff] [blame]1218
Bill Wendling9bd5d042011-12-05 21:27:54 +0000[diff] [blame]1219 <dt><tt><b><a name="returns_twice">returns_twice</a></b></tt></dt>
1220 <dd>This attribute indicates that this function can return twice. The
1221 C <code>setjmp</code> is an example of such a function. The compiler
1222 disables some optimizations (like tail calls) in the caller of these
1223 functions.</dd>
1224
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1225 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1226 <dd>This attribute indicates that the function should emit a stack smashing
1227 protector. It is in the form of a "canary"&mdash;a random value placed on
1228 the stack before the local variables that's checked upon return from the
1229 function to see if it has been overwritten. A heuristic is used to
1230 determine if a function needs stack protectors or not.<br>
1231<br>
1232 If a function that has an <tt>ssp</tt> attribute is inlined into a
1233 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1234 function will have an <tt>ssp</tt> attribute.</dd>
1235
Bill Wendlingf82d40a2009-11-02 00:24:16 +0000[diff] [blame]1236 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1237 <dd>This attribute indicates that the function should <em>always</em> emit a
1238 stack smashing protector. This overrides
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1239 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1240<br>
1241 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1242 function that doesn't have an <tt>sspreq</tt> attribute or which has
1243 an <tt>ssp</tt> attribute, then the resulting function will have
1244 an <tt>sspreq</tt> attribute.</dd>
Rafael Espindolafbff0ec2011-07-25 15:27:59 +0000[diff] [blame]1245
1246 <dt><tt><b><a name="uwtable">uwtable</a></b></tt></dt>
1247 <dd>This attribute indicates that the ABI being targeted requires that
1248 an unwind table entry be produce for this function even if we can
1249 show that no exceptions passes by it. This is normally the case for
1250 the ELF x86-64 abi, but it can be disabled for some compilation
1251 units.</dd>
Bill Wendlinge36dccc2008-09-07 10:26:33 +0000[diff] [blame]1252</dl>
1253
Devang Patelf8b94812008-09-04 23:05:13 +0000[diff] [blame]1254</div>
1255
1256<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1257<h3>
Chris Lattner1eeeb0c2006-04-08 04:40:53 +0000[diff] [blame]1258 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1259</h3>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1260
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1261<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1262
1263<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1264 the GCC "file scope inline asm" blocks. These blocks are internally
1265 concatenated by LLVM and treated as a single unit, but may be separated in
1266 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1267
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1268<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]1269module asm "inline asm code goes here"
1270module asm "more can go here"
1271</pre>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1272
1273<p>The strings can contain any character by escaping non-printable characters.
1274 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1275 for the number.</p>
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1276
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1277<p>The inline asm code is simply printed to the machine code .s file when
1278 assembly code is generated.</p>
1279
Chris Lattner4e9aba72006-01-23 23:23:47 +0000[diff] [blame]1280</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1281
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1282<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1283<h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1284 <a name="datalayout">Data Layout</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1285</h3>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1286
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1287<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1288
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1289<p>A module may specify a target specific data layout string that specifies how
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1290 data is to be laid out in memory. The syntax for the data layout is
1291 simply:</p>
1292
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]1293<pre class="doc_code">
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1294target datalayout = "<i>layout specification</i>"
1295</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1296
1297<p>The <i>layout specification</i> consists of a list of specifications
1298 separated by the minus sign character ('-'). Each specification starts with
1299 a letter and may include other information after the letter to define some
1300 aspect of the data layout. The specifications accepted are as follows:</p>
1301
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1302<dl>
1303 <dt><tt>E</tt></dt>
1304 <dd>Specifies that the target lays out data in big-endian form. That is, the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1305 bits with the most significance have the lowest address location.</dd>
1306
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1307 <dt><tt>e</tt></dt>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1308 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1309 the bits with the least significance have the lowest address
1310 location.</dd>
1311
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1312 <dt><tt>S<i>size</i></tt></dt>
1313 <dd>Specifies the natural alignment of the stack in bits. Alignment promotion
1314 of stack variables is limited to the natural stack alignment to avoid
1315 dynamic stack realignment. The stack alignment must be a multiple of
Lang Hames5f119a62011-10-11 17:50:14 +0000[diff] [blame]1316 8-bits. If omitted, the natural stack alignment defaults to "unspecified",
1317 which does not prevent any alignment promotions.</dd>
Lang Hamesbb5b3f32011-10-10 23:42:08 +0000[diff] [blame]1318
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1319 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1320 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1321 <i>preferred</i> alignments. All sizes are in bits. Specifying
1322 the <i>pref</i> alignment is optional. If omitted, the
1323 preceding <tt>:</tt> should be omitted too.</dd>
1324
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1325 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1326 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1327 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1328
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1329 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1330 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1331 <i>size</i>.</dd>
1332
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1333 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1334 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen9d8d2212010-05-28 18:54:47 +0000[diff] [blame]1335 <i>size</i>. Only values of <i>size</i> that are supported by the target
1336 will work. 32 (float) and 64 (double) are supported on all targets;
1337 80 or 128 (different flavors of long double) are also supported on some
1338 targets.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1339
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1340 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1341 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1342 <i>size</i>.</dd>
1343
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1344 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1345 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1346 <i>size</i>.</dd>
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1347
1348 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1349 <dd>This specifies a set of native integer widths for the target CPU
1350 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1351 "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]1352 this set are considered to support most general arithmetic
Chris Lattnere82bdc42009-11-07 09:35:34 +0000[diff] [blame]1353 operations efficiently.</dd>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1354</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1355
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1356<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman1c70c002010-04-28 00:36:01 +0000[diff] [blame]1357 default set of specifications which are then (possibly) overridden by the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1358 specifications in the <tt>datalayout</tt> keyword. The default specifications
1359 are given in this list:</p>
1360
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1361<ul>
1362 <li><tt>E</tt> - big endian</li>
Dan Gohmanfdf2e8c2010-02-23 02:44:03 +0000[diff] [blame]1363 <li><tt>p:64:64:64</tt> - 64-bit pointers with 64-bit alignment</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1364 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1365 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1366 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1367 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]1368 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1369 alignment of 64-bits</li>
1370 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1371 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1372 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1373 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1374 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar87bde0b2009-06-08 22:17:53 +0000[diff] [blame]1375 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1376</ul>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1377
1378<p>When LLVM is determining the alignment for a given type, it uses the
1379 following rules:</p>
1380
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1381<ol>
1382 <li>If the type sought is an exact match for one of the specifications, that
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1383 specification is used.</li>
1384
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1385 <li>If no match is found, and the type sought is an integer type, then the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1386 smallest integer type that is larger than the bitwidth of the sought type
1387 is used. If none of the specifications are larger than the bitwidth then
1388 the the largest integer type is used. For example, given the default
1389 specifications above, the i7 type will use the alignment of i8 (next
1390 largest) while both i65 and i256 will use the alignment of i64 (largest
1391 specified).</li>
1392
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1393 <li>If no match is found, and the type sought is a vector type, then the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1394 largest vector type that is smaller than the sought vector type will be
1395 used as a fall back. This happens because &lt;128 x double&gt; can be
1396 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1397</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1398
Chris Lattner6509f502011-10-11 23:01:39 +0000[diff] [blame]1399<p>The function of the data layout string may not be what you expect. Notably,
1400 this is not a specification from the frontend of what alignment the code
1401 generator should use.</p>
1402
1403<p>Instead, if specified, the target data layout is required to match what the
1404 ultimate <em>code generator</em> expects. This string is used by the
1405 mid-level optimizers to
1406 improve code, and this only works if it matches what the ultimate code
1407 generator uses. If you would like to generate IR that does not embed this
1408 target-specific detail into the IR, then you don't have to specify the
1409 string. This will disable some optimizations that require precise layout
1410 information, but this also prevents those optimizations from introducing
1411 target specificity into the IR.</p>
1412
1413
1414
Reid Spencerde151942007-02-19 23:54:10 +0000[diff] [blame]1415</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1416
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1417<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1418<h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1419 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1420</h3>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1421
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1422<div>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1423
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1424<p>Any memory access must be done through a pointer value associated
Andreas Bolka99a82052009-07-27 20:37:10 +0000[diff] [blame]1425with an address range of the memory access, otherwise the behavior
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1426is undefined. Pointer values are associated with address ranges
1427according to the following rules:</p>
1428
1429<ul>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1430 <li>A pointer value is associated with the addresses associated with
1431 any value it is <i>based</i> on.
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1432 <li>An address of a global variable is associated with the address
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1433 range of the variable's storage.</li>
1434 <li>The result value of an allocation instruction is associated with
1435 the address range of the allocated storage.</li>
1436 <li>A null pointer in the default address-space is associated with
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1437 no address.</li>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1438 <li>An integer constant other than zero or a pointer value returned
1439 from a function not defined within LLVM may be associated with address
1440 ranges allocated through mechanisms other than those provided by
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1441 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1442 allocated by mechanisms provided by LLVM.</li>
Dan Gohman1e109622010-07-02 18:41:32 +0000[diff] [blame]1443</ul>
1444
1445<p>A pointer value is <i>based</i> on another pointer value according
1446 to the following rules:</p>
1447
1448<ul>
1449 <li>A pointer value formed from a
1450 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1451 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1452 <li>The result value of a
1453 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1454 of the <tt>bitcast</tt>.</li>
1455 <li>A pointer value formed by an
1456 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1457 pointer values that contribute (directly or indirectly) to the
1458 computation of the pointer's value.</li>
1459 <li>The "<i>based</i> on" relationship is transitive.</li>
1460</ul>
1461
1462<p>Note that this definition of <i>"based"</i> is intentionally
1463 similar to the definition of <i>"based"</i> in C99, though it is
1464 slightly weaker.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1465
1466<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1467<tt><a href="#i_load">load</a></tt> merely indicates the size and
1468alignment of the memory from which to load, as well as the
Dan Gohmanc22c0f32010-06-17 19:23:50 +0000[diff] [blame]1469interpretation of the value. The first operand type of a
Andreas Bolka55e459a2009-07-29 00:02:05 +0000[diff] [blame]1470<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1471and alignment of the store.</p>
Dan Gohman556ca272009-07-27 18:07:55 +0000[diff] [blame]1472
1473<p>Consequently, type-based alias analysis, aka TBAA, aka
1474<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1475LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1476additional information which specialized optimization passes may use
1477to implement type-based alias analysis.</p>
1478
1479</div>
1480
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1481<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1482<h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1483 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1484</h3>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1485
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1486<div>
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]1487
1488<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1489href="#i_store"><tt>store</tt></a>s, and <a
1490href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1491The optimizers must not change the number of volatile operations or change their
1492order of execution relative to other volatile operations. The optimizers
1493<i>may</i> change the order of volatile operations relative to non-volatile
1494operations. This is not Java's "volatile" and has no cross-thread
1495synchronization behavior.</p>
1496
1497</div>
1498
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1499<!-- ======================================================================= -->
1500<h3>
1501 <a name="memmodel">Memory Model for Concurrent Operations</a>
1502</h3>
1503
1504<div>
1505
1506<p>The LLVM IR does not define any way to start parallel threads of execution
1507or to register signal handlers. Nonetheless, there are platform-specific
1508ways to create them, and we define LLVM IR's behavior in their presence. This
1509model is inspired by the C++0x memory model.</p>
1510
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1511<p>For a more informal introduction to this model, see the
1512<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.
1513
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1514<p>We define a <i>happens-before</i> partial order as the least partial order
1515that</p>
1516<ul>
1517 <li>Is a superset of single-thread program order, and</li>
1518 <li>When a <i>synchronizes-with</i> <tt>b</tt>, includes an edge from
1519 <tt>a</tt> to <tt>b</tt>. <i>Synchronizes-with</i> pairs are introduced
1520 by platform-specific techniques, like pthread locks, thread
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1521 creation, thread joining, etc., and by atomic instructions.
1522 (See also <a href="#ordering">Atomic Memory Ordering Constraints</a>).
1523 </li>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1524</ul>
1525
1526<p>Note that program order does not introduce <i>happens-before</i> edges
1527between a thread and signals executing inside that thread.</p>
1528
1529<p>Every (defined) read operation (load instructions, memcpy, atomic
1530loads/read-modify-writes, etc.) <var>R</var> reads a series of bytes written by
1531(defined) write operations (store instructions, atomic
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1532stores/read-modify-writes, memcpy, etc.). For the purposes of this section,
1533initialized globals are considered to have a write of the initializer which is
1534atomic and happens before any other read or write of the memory in question.
1535For each byte of a read <var>R</var>, <var>R<sub>byte</sub></var> may see
1536any write to the same byte, except:</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1537
1538<ul>
1539 <li>If <var>write<sub>1</sub></var> happens before
1540 <var>write<sub>2</sub></var>, and <var>write<sub>2</sub></var> happens
1541 before <var>R<sub>byte</sub></var>, then <var>R<sub>byte</sub></var>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1542 does not see <var>write<sub>1</sub></var>.
Bill Wendling0246bb72011-07-31 06:45:03 +0000[diff] [blame]1543 <li>If <var>R<sub>byte</sub></var> happens before
1544 <var>write<sub>3</sub></var>, then <var>R<sub>byte</sub></var> does not
1545 see <var>write<sub>3</sub></var>.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1546</ul>
1547
1548<p>Given that definition, <var>R<sub>byte</sub></var> is defined as follows:
1549<ul>
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1550 <li>If <var>R</var> is volatile, the result is target-dependent. (Volatile
1551 is supposed to give guarantees which can support
1552 <code>sig_atomic_t</code> in C/C++, and may be used for accesses to
1553 addresses which do not behave like normal memory. It does not generally
1554 provide cross-thread synchronization.)
1555 <li>Otherwise, if there is no write to the same byte that happens before
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1556 <var>R<sub>byte</sub></var>, <var>R<sub>byte</sub></var> returns
1557 <tt>undef</tt> for that byte.
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1558 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1559 <var>R<sub>byte</sub></var> returns the value written by that
1560 write.</li>
Eli Friedman118973a2011-07-22 03:04:45 +0000[diff] [blame]1561 <li>Otherwise, if <var>R</var> is atomic, and all the writes
1562 <var>R<sub>byte</sub></var> may see are atomic, it chooses one of the
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1563 values written. See the <a href="#ordering">Atomic Memory Ordering
1564 Constraints</a> section for additional constraints on how the choice
1565 is made.
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1566 <li>Otherwise <var>R<sub>byte</sub></var> returns <tt>undef</tt>.</li>
1567</ul>
1568
1569<p><var>R</var> returns the value composed of the series of bytes it read.
1570This implies that some bytes within the value may be <tt>undef</tt>
1571<b>without</b> the entire value being <tt>undef</tt>. Note that this only
1572defines the semantics of the operation; it doesn't mean that targets will
1573emit more than one instruction to read the series of bytes.</p>
1574
1575<p>Note that in cases where none of the atomic intrinsics are used, this model
1576places only one restriction on IR transformations on top of what is required
1577for single-threaded execution: introducing a store to a byte which might not
Eli Friedman101c81d2011-08-02 01:15:34 +0000[diff] [blame]1578otherwise be stored is not allowed in general. (Specifically, in the case
1579where another thread might write to and read from an address, introducing a
1580store can change a load that may see exactly one write into a load that may
1581see multiple writes.)</p>
Eli Friedman5b60e1b2011-07-20 21:35:53 +0000[diff] [blame]1582
1583<!-- FIXME: This model assumes all targets where concurrency is relevant have
1584a byte-size store which doesn't affect adjacent bytes. As far as I can tell,
1585none of the backends currently in the tree fall into this category; however,
1586there might be targets which care. If there are, we want a paragraph
1587like the following:
1588
1589Targets may specify that stores narrower than a certain width are not
1590available; on such a target, for the purposes of this model, treat any
1591non-atomic write with an alignment or width less than the minimum width
1592as if it writes to the relevant surrounding bytes.
1593-->
1594
1595</div>
1596
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1597<!-- ======================================================================= -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1598<h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1599 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1600</h3>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1601
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]1602<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1603
1604<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]1605<a href="#i_atomicrmw"><code>atomicrmw</code></a>,
1606<a href="#i_fence"><code>fence</code></a>,
1607<a href="#i_load"><code>atomic load</code></a>, and
Eli Friedman8fa281a2011-08-09 23:26:12 +0000[diff] [blame]1608<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1609that determines which other atomic instructions on the same address they
1610<i>synchronize with</i>. These semantics are borrowed from Java and C++0x,
1611but are somewhat more colloquial. If these descriptions aren't precise enough,
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1612check those specs (see spec references in the
1613<a href="Atomic.html#introduction">atomics guide</a>).
1614<a href="#i_fence"><code>fence</code></a> instructions
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1615treat these orderings somewhat differently since they don't take an address.
1616See that instruction's documentation for details.</p>
1617
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1618<p>For a simpler introduction to the ordering constraints, see the
1619<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.</p>
1620
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1621<dl>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1622<dt><code>unordered</code></dt>
1623<dd>The set of values that can be read is governed by the happens-before
1624partial order. A value cannot be read unless some operation wrote it.
1625This is intended to provide a guarantee strong enough to model Java's
1626non-volatile shared variables. This ordering cannot be specified for
1627read-modify-write operations; it is not strong enough to make them atomic
1628in any interesting way.</dd>
1629<dt><code>monotonic</code></dt>
1630<dd>In addition to the guarantees of <code>unordered</code>, there is a single
1631total order for modifications by <code>monotonic</code> operations on each
1632address. All modification orders must be compatible with the happens-before
1633order. There is no guarantee that the modification orders can be combined to
1634a global total order for the whole program (and this often will not be
1635possible). The read in an atomic read-modify-write operation
1636(<a href="#i_cmpxchg"><code>cmpxchg</code></a> and
1637<a href="#i_atomicrmw"><code>atomicrmw</code></a>)
1638reads the value in the modification order immediately before the value it
1639writes. If one atomic read happens before another atomic read of the same
1640address, the later read must see the same value or a later value in the
1641address's modification order. This disallows reordering of
1642<code>monotonic</code> (or stronger) operations on the same address. If an
1643address is written <code>monotonic</code>ally by one thread, and other threads
1644<code>monotonic</code>ally read that address repeatedly, the other threads must
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1645eventually see the write. This corresponds to the C++0x/C1x
1646<code>memory_order_relaxed</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1647<dt><code>acquire</code></dt>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1648<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedmanc264b2f2011-08-24 20:28:39 +0000[diff] [blame]1649a <i>synchronizes-with</i> edge may be formed with a <code>release</code>
1650operation. This is intended to model C++'s <code>memory_order_acquire</code>.</dd>
1651<dt><code>release</code></dt>
1652<dd>In addition to the guarantees of <code>monotonic</code>, if this operation
1653writes a value which is subsequently read by an <code>acquire</code> operation,
1654it <i>synchronizes-with</i> that operation. (This isn't a complete
1655description; see the C++0x definition of a release sequence.) This corresponds
1656to the C++0x/C1x <code>memory_order_release</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1657<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1658<code>acquire</code> and <code>release</code> operation on its address.
1659This corresponds to the C++0x/C1x <code>memory_order_acq_rel</code>.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1660<dt><code>seq_cst</code> (sequentially consistent)</dt><dd>
1661<dd>In addition to the guarantees of <code>acq_rel</code>
1662(<code>acquire</code> for an operation which only reads, <code>release</code>
1663for an operation which only writes), there is a global total order on all
1664sequentially-consistent operations on all addresses, which is consistent with
1665the <i>happens-before</i> partial order and with the modification orders of
1666all the affected addresses. Each sequentially-consistent read sees the last
Eli Friedman234bccd2011-08-22 21:35:27 +0000[diff] [blame]1667preceding write to the same address in this global order. This corresponds
1668to the C++0x/C1x <code>memory_order_seq_cst</code> and Java volatile.</dd>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]1669</dl>
1670
1671<p id="singlethread">If an atomic operation is marked <code>singlethread</code>,
1672it only <i>synchronizes with</i> or participates in modification and seq_cst
1673total orderings with other operations running in the same thread (for example,
1674in signal handlers).</p>
1675
1676</div>
1677
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1678</div>
1679
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1680<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1681<h2><a name="typesystem">Type System</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1682<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1683
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1684<div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1685
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1686<p>The LLVM type system is one of the most important features of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1687 intermediate representation. Being typed enables a number of optimizations
1688 to be performed on the intermediate representation directly, without having
1689 to do extra analyses on the side before the transformation. A strong type
1690 system makes it easier to read the generated code and enables novel analyses
1691 and transformations that are not feasible to perform on normal three address
1692 code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]1693
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1694<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1695<h3>
1696 <a name="t_classifications">Type Classifications</a>
1697</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1698
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1699<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1700
1701<p>The types fall into a few useful classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1702
1703<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1704 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1705 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1706 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1707 <td><a href="#t_integer">integer</a></td>
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1708 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1709 </tr>
1710 <tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1711 <td><a href="#t_floating">floating point</a></td>
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]1712 <td><tt>half, float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1713 </tr>
1714 <tr>
1715 <td><a name="t_firstclass">first class</a></td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1716 <td><a href="#t_integer">integer</a>,
1717 <a href="#t_floating">floating point</a>,
1718 <a href="#t_pointer">pointer</a>,
Dan Gohman0066db62008-06-18 18:42:13 +0000[diff] [blame]1719 <a href="#t_vector">vector</a>,
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]1720 <a href="#t_struct">structure</a>,
1721 <a href="#t_array">array</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1722 <a href="#t_label">label</a>,
1723 <a href="#t_metadata">metadata</a>.
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]1724 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1725 </tr>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1726 <tr>
1727 <td><a href="#t_primitive">primitive</a></td>
1728 <td><a href="#t_label">label</a>,
1729 <a href="#t_void">void</a>,
Tobias Grosser05387292010-12-28 20:29:31 +0000[diff] [blame]1730 <a href="#t_integer">integer</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1731 <a href="#t_floating">floating point</a>,
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1732 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1733 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1734 </tr>
1735 <tr>
1736 <td><a href="#t_derived">derived</a></td>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1737 <td><a href="#t_array">array</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1738 <a href="#t_function">function</a>,
1739 <a href="#t_pointer">pointer</a>,
1740 <a href="#t_struct">structure</a>,
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1741 <a href="#t_vector">vector</a>,
1742 <a href="#t_opaque">opaque</a>.
Dan Gohman01ac1012008-10-14 16:32:04 +0000[diff] [blame]1743 </td>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1744 </tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1745 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1746</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1747
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1748<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1749 important. Values of these types are the only ones which can be produced by
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1750 instructions.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1751
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1752</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1753
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1754<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1755<h3>
1756 <a name="t_primitive">Primitive Types</a>
1757</h3>
Chris Lattner8f8c7b72008-01-04 04:34:14 +0000[diff] [blame]1758
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1759<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1760
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1761<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1762 system.</p>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1763
1764<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1765<h4>
1766 <a name="t_integer">Integer Type</a>
1767</h4>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1768
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1769<div>
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1770
1771<h5>Overview:</h5>
1772<p>The integer type is a very simple type that simply specifies an arbitrary
1773 bit width for the integer type desired. Any bit width from 1 bit to
1774 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1775
1776<h5>Syntax:</h5>
1777<pre>
1778 iN
1779</pre>
1780
1781<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1782 value.</p>
1783
1784<h5>Examples:</h5>
1785<table class="layout">
1786 <tr class="layout">
1787 <td class="left"><tt>i1</tt></td>
1788 <td class="left">a single-bit integer.</td>
1789 </tr>
1790 <tr class="layout">
1791 <td class="left"><tt>i32</tt></td>
1792 <td class="left">a 32-bit integer.</td>
1793 </tr>
1794 <tr class="layout">
1795 <td class="left"><tt>i1942652</tt></td>
1796 <td class="left">a really big integer of over 1 million bits.</td>
1797 </tr>
1798</table>
1799
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1800</div>
1801
1802<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1803<h4>
1804 <a name="t_floating">Floating Point Types</a>
1805</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1806
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1807<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1808
1809<table>
1810 <tbody>
1811 <tr><th>Type</th><th>Description</th></tr>
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]1812 <tr><td><tt>half</tt></td><td>16-bit floating point value</td></tr>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1813 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1814 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1815 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1816 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1817 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1818 </tbody>
1819</table>
1820
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1821</div>
1822
1823<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1824<h4>
1825 <a name="t_x86mmx">X86mmx Type</a>
1826</h4>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1827
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1828<div>
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1829
1830<h5>Overview:</h5>
1831<p>The x86mmx type represents a value held in an MMX register on an x86 machine. The operations allowed on it are quite limited: parameters and return values, load and store, and bitcast. User-specified MMX instructions are represented as intrinsic or asm calls with arguments and/or results of this type. There are no arrays, vectors or constants of this type.</p>
1832
1833<h5>Syntax:</h5>
1834<pre>
Dale Johannesen473a8c82010-10-01 01:07:02 +0000[diff] [blame]1835 x86mmx
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]1836</pre>
1837
1838</div>
1839
1840<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1841<h4>
1842 <a name="t_void">Void Type</a>
1843</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1844
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1845<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1846
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1847<h5>Overview:</h5>
1848<p>The void type does not represent any value and has no size.</p>
1849
1850<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1851<pre>
1852 void
1853</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1854
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1855</div>
1856
1857<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1858<h4>
1859 <a name="t_label">Label Type</a>
1860</h4>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1861
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1862<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1863
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1864<h5>Overview:</h5>
1865<p>The label type represents code labels.</p>
1866
1867<h5>Syntax:</h5>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1868<pre>
1869 label
1870</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1871
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1872</div>
1873
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1874<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1875<h4>
1876 <a name="t_metadata">Metadata Type</a>
1877</h4>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1878
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1879<div>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1880
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1881<h5>Overview:</h5>
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]1882<p>The metadata type represents embedded metadata. No derived types may be
1883 created from metadata except for <a href="#t_function">function</a>
1884 arguments.
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1885
1886<h5>Syntax:</h5>
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1887<pre>
1888 metadata
1889</pre>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]1890
Nick Lewycky7a0370f2009-05-30 05:06:04 +0000[diff] [blame]1891</div>
1892
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1893</div>
Chris Lattner4f69f462008-01-04 04:32:38 +0000[diff] [blame]1894
1895<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1896<h3>
1897 <a name="t_derived">Derived Types</a>
1898</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1899
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1900<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1901
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1902<p>The real power in LLVM comes from the derived types in the system. This is
1903 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]1904 useful types. Each of these types contain one or more element types which
1905 may be a primitive type, or another derived type. For example, it is
1906 possible to have a two dimensional array, using an array as the element type
1907 of another array.</p>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]1908
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1909<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1910<h4>
1911 <a name="t_aggregate">Aggregate Types</a>
1912</h4>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1913
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1914<div>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1915
1916<p>Aggregate Types are a subset of derived types that can contain multiple
Duncan Sands20536b52011-12-14 15:44:20 +0000[diff] [blame]1917 member types. <a href="#t_array">Arrays</a> and
1918 <a href="#t_struct">structs</a> are aggregate types.
1919 <a href="#t_vector">Vectors</a> are not considered to be aggregate types.</p>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]1920
1921</div>
1922
Reid Spencer2b916312007-05-16 18:44:01 +0000[diff] [blame]1923<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1924<h4>
1925 <a name="t_array">Array Type</a>
1926</h4>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1927
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1928<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1929
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1930<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1931<p>The array type is a very simple derived type that arranges elements
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1932 sequentially in memory. The array type requires a size (number of elements)
1933 and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1934
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1935<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1936<pre>
1937 [&lt;# elements&gt; x &lt;elementtype&gt;]
1938</pre>
1939
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1940<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1941 be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1942
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1943<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1944<table class="layout">
1945 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1946 <td class="left"><tt>[40 x i32]</tt></td>
1947 <td class="left">Array of 40 32-bit integer values.</td>
1948 </tr>
1949 <tr class="layout">
1950 <td class="left"><tt>[41 x i32]</tt></td>
1951 <td class="left">Array of 41 32-bit integer values.</td>
1952 </tr>
1953 <tr class="layout">
1954 <td class="left"><tt>[4 x i8]</tt></td>
1955 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1956 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1957</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1958<p>Here are some examples of multidimensional arrays:</p>
1959<table class="layout">
1960 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]1961 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1962 <td class="left">3x4 array of 32-bit integer values.</td>
1963 </tr>
1964 <tr class="layout">
1965 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1966 <td class="left">12x10 array of single precision floating point values.</td>
1967 </tr>
1968 <tr class="layout">
1969 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1970 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1971 </tr>
1972</table>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1973
Dan Gohman7657f6b2009-11-09 19:01:53 +0000[diff] [blame]1974<p>There is no restriction on indexing beyond the end of the array implied by
1975 a static type (though there are restrictions on indexing beyond the bounds
1976 of an allocated object in some cases). This means that single-dimension
1977 'variable sized array' addressing can be implemented in LLVM with a zero
1978 length array type. An implementation of 'pascal style arrays' in LLVM could
1979 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]1980
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1981</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]1982
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1983<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1984<h4>
1985 <a name="t_function">Function Type</a>
1986</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1987
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1988<div>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1989
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1990<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]1991<p>The function type can be thought of as a function signature. It consists of
1992 a return type and a list of formal parameter types. The return type of a
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]1993 function type is a first class type or a void type.</p>
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]1994
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1995<h5>Syntax:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1996<pre>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]1997 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]1998</pre>
1999
John Criswell0ec250c2005-10-24 16:17:18 +0000[diff] [blame]2000<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2001 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
2002 which indicates that the function takes a variable number of arguments.
2003 Variable argument functions can access their arguments with
2004 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2005 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyc261df92009-09-27 23:27:42 +0000[diff] [blame]2006 <a href="#t_label">label</a>.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]2007
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2008<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2009<table class="layout">
2010 <tr class="layout">
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2011 <td class="left"><tt>i32 (i32)</tt></td>
2012 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2013 </td>
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2014 </tr><tr class="layout">
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2015 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencerf17a0b72006-12-31 07:20:23 +0000[diff] [blame]2016 </tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2017 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]2018 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
2019 returning <tt>float</tt>.
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2020 </td>
2021 </tr><tr class="layout">
2022 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2023 <td class="left">A vararg function that takes at least one
2024 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
2025 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer92f82302006-12-31 07:18:34 +0000[diff] [blame]2026 LLVM.
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2027 </td>
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2028 </tr><tr class="layout">
2029 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky51386942009-09-27 07:55:32 +0000[diff] [blame]2030 <td class="left">A function taking an <tt>i32</tt>, returning a
2031 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patela582f402008-03-24 05:35:41 +0000[diff] [blame]2032 </td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2033 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2034</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]2035
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2036</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2037
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2038<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2039<h4>
2040 <a name="t_struct">Structure Type</a>
2041</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2042
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2043<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2044
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2045<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2046<p>The structure type is used to represent a collection of data members together
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2047 in memory. The elements of a structure may be any type that has a size.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2048
Jeffrey Yasskin7a088cf2010-01-11 19:19:26 +0000[diff] [blame]2049<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
2050 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
2051 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2052 Structures in registers are accessed using the
2053 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
2054 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2055
2056<p>Structures may optionally be "packed" structures, which indicate that the
2057 alignment of the struct is one byte, and that there is no padding between
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2058 the elements. In non-packed structs, padding between field types is inserted
2059 as defined by the TargetData string in the module, which is required to match
Chris Lattnere4617b02011-10-11 23:02:17 +0000[diff] [blame]2060 what the underlying code generator expects.</p>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2061
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2062<p>Structures can either be "literal" or "identified". A literal structure is
2063 defined inline with other types (e.g. <tt>{i32, i32}*</tt>) whereas identified
2064 types are always defined at the top level with a name. Literal types are
2065 uniqued by their contents and can never be recursive or opaque since there is
Chris Lattneraa175c32011-08-12 18:12:40 +0000[diff] [blame]2066 no way to write one. Identified types can be recursive, can be opaqued, and are
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2067 never uniqued.
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2068</p>
2069
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2070<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2071<pre>
Chris Lattner2c38d652011-08-12 17:31:02 +0000[diff] [blame]2072 %T1 = type { &lt;type list&gt; } <i>; Identified normal struct type</i>
2073 %T2 = type &lt;{ &lt;type list&gt; }&gt; <i>; Identified packed struct type</i>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2074</pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2075
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2076<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2077<table class="layout">
2078 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2079 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
2080 <td class="left">A triple of three <tt>i32</tt> values</td>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2081 </tr>
2082 <tr class="layout">
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]2083 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
2084 <td class="left">A pair, where the first element is a <tt>float</tt> and the
2085 second element is a <a href="#t_pointer">pointer</a> to a
2086 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
2087 an <tt>i32</tt>.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2088 </tr>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2089 <tr class="layout">
2090 <td class="left"><tt>&lt;{ i8, i32 }&gt;</tt></td>
2091 <td class="left">A packed struct known to be 5 bytes in size.</td>
2092 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2093</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2094
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2095</div>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2096
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2097<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2098<h4>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2099 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2100</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2101
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2102<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2103
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2104<h5>Overview:</h5>
Chris Lattner628ed392011-07-23 19:59:08 +0000[diff] [blame]2105<p>Opaque structure types are used to represent named structure types that do
2106 not have a body specified. This corresponds (for example) to the C notion of
2107 a forward declared structure.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2108
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2109<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2110<pre>
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2111 %X = type opaque
2112 %52 = type opaque
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2113</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2114
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2115<h5>Examples:</h5>
2116<table class="layout">
2117 <tr class="layout">
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2118 <td class="left"><tt>opaque</tt></td>
2119 <td class="left">An opaque type.</td>
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2120 </tr>
2121</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2122
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2123</div>
2124
Chris Lattner1afcace2011-07-09 17:41:24 +0000[diff] [blame]2125
2126
Andrew Lenharth75e10682006-12-08 17:13:00 +0000[diff] [blame]2127<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2128<h4>
2129 <a name="t_pointer">Pointer Type</a>
2130</h4>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2131
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2132<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2133
2134<h5>Overview:</h5>
Dan Gohmanff3ef322010-02-25 16:50:07 +0000[diff] [blame]2135<p>The pointer type is used to specify memory locations.
2136 Pointers are commonly used to reference objects in memory.</p>
2137
2138<p>Pointer types may have an optional address space attribute defining the
2139 numbered address space where the pointed-to object resides. The default
2140 address space is number zero. The semantics of non-zero address
2141 spaces are target-specific.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2142
2143<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
2144 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner0fd4a272009-02-08 19:53:29 +0000[diff] [blame]2145
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2146<h5>Syntax:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]2147<pre>
2148 &lt;type&gt; *
2149</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2150
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]2151<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2152<table class="layout">
2153 <tr class="layout">
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]2154 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2155 <td class="left">A <a href="#t_pointer">pointer</a> to <a
2156 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
2157 </tr>
2158 <tr class="layout">
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]2159 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2160 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]2161 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2162 <tt>i32</tt>.</td>
2163 </tr>
2164 <tr class="layout">
2165 <td class="left"><tt>i32 addrspace(5)*</tt></td>
2166 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
2167 that resides in address space #5.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2168 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2169</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2170
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2171</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2172
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2173<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2174<h4>
2175 <a name="t_vector">Vector Type</a>
2176</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2177
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2178<div>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2179
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2180<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2181<p>A vector type is a simple derived type that represents a vector of elements.
2182 Vector types are used when multiple primitive data are operated in parallel
2183 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sandsd40d14e2009-11-27 13:38:03 +0000[diff] [blame]2184 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2185 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2186
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2187<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2188<pre>
2189 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2190</pre>
2191
Chris Lattner7d2e7be2010-10-10 18:20:35 +0000[diff] [blame]2192<p>The number of elements is a constant integer value larger than 0; elementtype
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]2193 may be any integer or floating point type, or a pointer to these types.
2194 Vectors of size zero are not allowed. </p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]2195
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]2196<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2197<table class="layout">
2198 <tr class="layout">
Chris Lattner23ff1f92007-12-19 05:04:11 +0000[diff] [blame]2199 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
2200 <td class="left">Vector of 4 32-bit integer values.</td>
2201 </tr>
2202 <tr class="layout">
2203 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
2204 <td class="left">Vector of 8 32-bit floating-point values.</td>
2205 </tr>
2206 <tr class="layout">
2207 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
2208 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2209 </tr>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]2210 <tr class="layout">
2211 <td class="left"><tt>&lt;4 x i64*&gt;</tt></td>
2212 <td class="left">Vector of 4 pointers to 64-bit integer values.</td>
2213 </tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]2214</table>
Dan Gohmand8791e52009-01-24 15:58:40 +0000[diff] [blame]2215
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2216</div>
2217
Bill Wendlingaf75f0c2011-07-31 06:47:33 +0000[diff] [blame]2218</div>
2219
NAKAMURA Takumi4b2e07a2011-10-31 13:04:26 +0000[diff] [blame]2220</div>
2221
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2222<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2223<h2><a name="constants">Constants</a></h2>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2224<!-- *********************************************************************** -->
2225
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2226<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2227
2228<p>LLVM has several different basic types of constants. This section describes
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2229 them all and their syntax.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2230
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2231<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2232<h3>
2233 <a name="simpleconstants">Simple Constants</a>
2234</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2235
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2236<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2237
2238<dl>
2239 <dt><b>Boolean constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2240 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]2241 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2242
2243 <dt><b>Integer constants</b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2244 <dd>Standard integers (such as '4') are constants of
2245 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2246 with integer types.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2247
2248 <dt><b>Floating point constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2249 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2250 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2251 notation (see below). The assembler requires the exact decimal value of a
2252 floating-point constant. For example, the assembler accepts 1.25 but
2253 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2254 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2255
2256 <dt><b>Null pointer constants</b></dt>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2257 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2258 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2259</dl>
2260
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2261<p>The one non-intuitive notation for constants is the hexadecimal form of
2262 floating point constants. For example, the form '<tt>double
2263 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2264 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2265 constants are required (and the only time that they are generated by the
2266 disassembler) is when a floating point constant must be emitted but it cannot
2267 be represented as a decimal floating point number in a reasonable number of
2268 digits. For example, NaN's, infinities, and other special values are
2269 represented in their IEEE hexadecimal format so that assembly and disassembly
2270 do not cause any bits to change in the constants.</p>
2271
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]2272<p>When using the hexadecimal form, constants of types half, float, and double are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2273 represented using the 16-digit form shown above (which matches the IEEE754
Dan Gohmance163392011-12-17 00:04:22 +0000[diff] [blame]2274 representation for double); half and float values must, however, be exactly
2275 representable as IEE754 half and single precision, respectively.
2276 Hexadecimal format is always used
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2277 for long double, and there are three forms of long double. The 80-bit format
2278 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2279 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2280 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2281 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2282 currently supported target uses this format. Long doubles will only work if
2283 they match the long double format on your target. All hexadecimal formats
2284 are big-endian (sign bit at the left).</p>
2285
Dale Johannesen21fe99b2010-10-01 00:48:59 +0000[diff] [blame]2286<p>There are no constants of type x86mmx.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2287</div>
2288
2289<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2290<h3>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]2291<a name="aggregateconstants"></a> <!-- old anchor -->
2292<a name="complexconstants">Complex Constants</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2293</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2294
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2295<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2296
Chris Lattner70882792009-02-28 18:32:25 +0000[diff] [blame]2297<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2298 constants and smaller complex constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2299
2300<dl>
2301 <dt><b>Structure constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2302 <dd>Structure constants are represented with notation similar to structure
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2303 type definitions (a comma separated list of elements, surrounded by braces
2304 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2305 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2306 Structure constants must have <a href="#t_struct">structure type</a>, and
2307 the number and types of elements must match those specified by the
2308 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2309
2310 <dt><b>Array constants</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2311 <dd>Array constants are represented with notation similar to array type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2312 definitions (a comma separated list of elements, surrounded by square
2313 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2314 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2315 the number and types of elements must match those specified by the
2316 type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2317
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2318 <dt><b>Vector constants</b></dt>
Reid Spencer485bad12007-02-15 03:07:05 +0000[diff] [blame]2319 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2320 definitions (a comma separated list of elements, surrounded by
2321 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2322 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2323 have <a href="#t_vector">vector type</a>, and the number and types of
2324 elements must match those specified by the type.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2325
2326 <dt><b>Zero initialization</b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2327 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]2328 value to zero of <em>any</em> type, including scalar and
2329 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2330 This is often used to avoid having to print large zero initializers
2331 (e.g. for large arrays) and is always exactly equivalent to using explicit
2332 zero initializers.</dd>
Nick Lewycky21cc4462009-04-04 07:22:01 +0000[diff] [blame]2333
2334 <dt><b>Metadata node</b></dt>
Nick Lewycky1e8c7a62009-05-30 16:08:30 +0000[diff] [blame]2335 <dd>A metadata node is a structure-like constant with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2336 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2337 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2338 be interpreted as part of the instruction stream, metadata is a place to
2339 attach additional information such as debug info.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2340</dl>
2341
2342</div>
2343
2344<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2345<h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2346 <a name="globalconstants">Global Variable and Function Addresses</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2347</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2348
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2349<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2350
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2351<p>The addresses of <a href="#globalvars">global variables</a>
2352 and <a href="#functionstructure">functions</a> are always implicitly valid
2353 (link-time) constants. These constants are explicitly referenced when
2354 the <a href="#identifiers">identifier for the global</a> is used and always
2355 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2356 legal LLVM file:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2357
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2358<pre class="doc_code">
Chris Lattnera18a4242007-06-06 18:28:13 +0000[diff] [blame]2359@X = global i32 17
2360@Y = global i32 42
2361@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2362</pre>
2363
2364</div>
2365
2366<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2367<h3>
2368 <a name="undefvalues">Undefined Values</a>
2369</h3>
2370
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2371<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2372
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2373<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]2374 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2375 Undefined values may be of any type (other than '<tt>label</tt>'
2376 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2377
Chris Lattnerc608cb12009-09-11 01:49:31 +0000[diff] [blame]2378<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2379 program is well defined no matter what value is used. This gives the
2380 compiler more freedom to optimize. Here are some examples of (potentially
2381 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2382
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2383
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2384<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2385 %A = add %X, undef
2386 %B = sub %X, undef
2387 %C = xor %X, undef
2388Safe:
2389 %A = undef
2390 %B = undef
2391 %C = undef
2392</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2393
2394<p>This is safe because all of the output bits are affected by the undef bits.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2395 Any output bit can have a zero or one depending on the input bits.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2396
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2397<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2398 %A = or %X, undef
2399 %B = and %X, undef
2400Safe:
2401 %A = -1
2402 %B = 0
2403Unsafe:
2404 %A = undef
2405 %B = undef
2406</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2407
2408<p>These logical operations have bits that are not always affected by the input.
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2409 For example, if <tt>%X</tt> has a zero bit, then the output of the
2410 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2411 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2412 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2413 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2414 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2415 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2416 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2417
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2418<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2419 %A = select undef, %X, %Y
2420 %B = select undef, 42, %Y
2421 %C = select %X, %Y, undef
2422Safe:
2423 %A = %X (or %Y)
2424 %B = 42 (or %Y)
2425 %C = %Y
2426Unsafe:
2427 %A = undef
2428 %B = undef
2429 %C = undef
2430</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2431
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2432<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2433 branch) conditions can go <em>either way</em>, but they have to come from one
2434 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2435 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2436 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2437 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2438 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2439 eliminated.</p>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2440
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2441<pre class="doc_code">
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2442 %A = xor undef, undef
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2443
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2444 %B = undef
2445 %C = xor %B, %B
2446
2447 %D = undef
2448 %E = icmp lt %D, 4
2449 %F = icmp gte %D, 4
2450
2451Safe:
2452 %A = undef
2453 %B = undef
2454 %C = undef
2455 %D = undef
2456 %E = undef
2457 %F = undef
2458</pre>
Chris Lattner48a109c2009-09-07 22:52:39 +0000[diff] [blame]2459
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2460<p>This example points out that two '<tt>undef</tt>' operands are not
2461 necessarily the same. This can be surprising to people (and also matches C
2462 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2463 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2464 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2465 its value over its "live range". This is true because the variable doesn't
2466 actually <em>have a live range</em>. Instead, the value is logically read
2467 from arbitrary registers that happen to be around when needed, so the value
2468 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2469 need to have the same semantics or the core LLVM "replace all uses with"
2470 concept would not hold.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2471
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2472<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2473 %A = fdiv undef, %X
2474 %B = fdiv %X, undef
2475Safe:
2476 %A = undef
2477b: unreachable
2478</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2479
2480<p>These examples show the crucial difference between an <em>undefined
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2481 value</em> and <em>undefined behavior</em>. An undefined value (like
2482 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2483 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2484 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2485 defined on SNaN's. However, in the second example, we can make a more
2486 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2487 arbitrary value, we are allowed to assume that it could be zero. Since a
2488 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2489 the operation does not execute at all. This allows us to delete the divide and
2490 all code after it. Because the undefined operation "can't happen", the
2491 optimizer can assume that it occurs in dead code.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2492
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2493<pre class="doc_code">
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2494a: store undef -> %X
2495b: store %X -> undef
2496Safe:
2497a: &lt;deleted&gt;
2498b: unreachable
2499</pre>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2500
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2501<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2502 undefined value can be assumed to not have any effect; we can assume that the
2503 value is overwritten with bits that happen to match what was already there.
2504 However, a store <em>to</em> an undefined location could clobber arbitrary
2505 memory, therefore, it has undefined behavior.</p>
Chris Lattner6e9057b2009-09-07 23:33:52 +0000[diff] [blame]2506
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2507</div>
2508
2509<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2510<h3>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2511 <a name="poisonvalues">Poison Values</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2512</h3>
2513
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2514<div>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2515
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2516<p>Poison values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2517 they also represent the fact that an instruction or constant expression which
2518 cannot evoke side effects has nevertheless detected a condition which results
2519 in undefined behavior.</p>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2520
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2521<p>There is currently no way of representing a poison value in the IR; they
Dan Gohman855abed2010-05-03 14:51:43 +0000[diff] [blame]2522 only exist when produced by operations such as
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2523 <a href="#i_add"><tt>add</tt></a> with the <tt>nsw</tt> flag.</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2524
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2525<p>Poison value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2526
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2527<ul>
2528<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2529 their operands.</li>
2530
2531<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2532 to their dynamic predecessor basic block.</li>
2533
2534<li>Function arguments depend on the corresponding actual argument values in
2535 the dynamic callers of their functions.</li>
2536
2537<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2538 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2539 control back to them.</li>
2540
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2541<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2542 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2543 or exception-throwing call instructions that dynamically transfer control
2544 back to them.</li>
2545
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2546<li>Non-volatile loads and stores depend on the most recent stores to all of the
2547 referenced memory addresses, following the order in the IR
2548 (including loads and stores implied by intrinsics such as
2549 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2550
Dan Gohman7c24ff12010-05-03 14:59:34 +0000[diff] [blame]2551<!-- TODO: In the case of multiple threads, this only applies if the store
2552 "happens-before" the load or store. -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2553
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2554<!-- TODO: floating-point exception state -->
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2555
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2556<li>An instruction with externally visible side effects depends on the most
2557 recent preceding instruction with externally visible side effects, following
Dan Gohmanff70fe42010-07-06 15:26:33 +0000[diff] [blame]2558 the order in the IR. (This includes
2559 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2560
Dan Gohmanb5328162010-05-03 14:55:22 +0000[diff] [blame]2561<li>An instruction <i>control-depends</i> on a
2562 <a href="#terminators">terminator instruction</a>
2563 if the terminator instruction has multiple successors and the instruction
2564 is always executed when control transfers to one of the successors, and
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2565 may not be executed when control is transferred to another.</li>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2566
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2567<li>Additionally, an instruction also <i>control-depends</i> on a terminator
2568 instruction if the set of instructions it otherwise depends on would be
Chris Lattner7a2bdde2011-04-15 05:18:47 +0000[diff] [blame]2569 different if the terminator had transferred control to a different
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2570 successor.</li>
2571
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2572<li>Dependence is transitive.</li>
2573
2574</ul>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2575
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2576<p>Poison Values have the same behavior as <a href="#undefvalues">undef values</a>,
2577 with the additional affect that any instruction which has a <i>dependence</i>
2578 on a poison value has undefined behavior.</p>
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2579
2580<p>Here are some examples:</p>
Dan Gohmanc30f6e12010-04-26 20:54:53 +0000[diff] [blame]2581
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2582<pre class="doc_code">
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2583entry:
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2584 %poison = sub nuw i32 0, 1 ; Results in a poison value.
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2585 %still_poison = and i32 %poison, 0 ; 0, but also poison.
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2586 %poison_yet_again = getelementptr i32* @h, i32 %still_poison
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2587 store i32 0, i32* %poison_yet_again ; memory at @h[0] is poisoned
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2588
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2589 store i32 %poison, i32* @g ; Poison value stored to memory.
2590 %poison2 = load i32* @g ; Poison value loaded back from memory.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2591
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2592 store volatile i32 %poison, i32* @g ; External observation; undefined behavior.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2593
2594 %narrowaddr = bitcast i32* @g to i16*
2595 %wideaddr = bitcast i32* @g to i64*
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]2596 %poison3 = load i16* %narrowaddr ; Returns a poison value.
2597 %poison4 = load i64* %wideaddr ; Returns a poison value.
Dan Gohman34b3d992010-04-28 00:49:41 +0000[diff] [blame]2598
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2599 %cmp = icmp slt i32 %poison, 0 ; Returns a poison value.
2600 br i1 %cmp, label %true, label %end ; Branch to either destination.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2601
2602true:
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2603 store volatile i32 0, i32* @g ; This is control-dependent on %cmp, so
2604 ; it has undefined behavior.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2605 br label %end
2606
2607end:
2608 %p = phi i32 [ 0, %entry ], [ 1, %true ]
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2609 ; Both edges into this PHI are
2610 ; control-dependent on %cmp, so this
2611 ; always results in a poison value.
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2612
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2613 store volatile i32 0, i32* @g ; This would depend on the store in %true
2614 ; if %cmp is true, or the store in %entry
2615 ; otherwise, so this is undefined behavior.
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2616
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2617 br i1 %cmp, label %second_true, label %second_end
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2618 ; The same branch again, but this time the
2619 ; true block doesn't have side effects.
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2620
2621second_true:
2622 ; No side effects!
Nick Lewycky64f9fb12011-05-16 19:29:30 +0000[diff] [blame]2623 ret void
Dan Gohmanca4cac42011-04-12 23:05:59 +0000[diff] [blame]2624
2625second_end:
Dan Gohman5cdc51e2011-12-06 03:31:14 +0000[diff] [blame]2626 store volatile i32 0, i32* @g ; This time, the instruction always depends
2627 ; on the store in %end. Also, it is
2628 ; control-equivalent to %end, so this is
Dan Gohmane1a29842011-12-06 03:35:58 +0000[diff] [blame]2629 ; well-defined (ignoring earlier undefined
2630 ; behavior in this example).
Dan Gohmanae11c3f2010-04-26 23:36:52 +0000[diff] [blame]2631</pre>
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2632
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]2633</div>
2634
2635<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2636<h3>
2637 <a name="blockaddress">Addresses of Basic Blocks</a>
2638</h3>
2639
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2640<div>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2641
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2642<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2643
2644<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner2dfdf2a2009-10-27 21:49:40 +0000[diff] [blame]2645 basic block in the specified function, and always has an i8* type. Taking
Chris Lattnercdfc9402009-11-01 01:27:45 +0000[diff] [blame]2646 the address of the entry block is illegal.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2647
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2648<p>This value only has defined behavior when used as an operand to the
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2649 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2650 comparisons against null. Pointer equality tests between labels addresses
2651 results in undefined behavior &mdash; though, again, comparison against null
2652 is ok, and no label is equal to the null pointer. This may be passed around
2653 as an opaque pointer sized value as long as the bits are not inspected. This
2654 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2655 long as the original value is reconstituted before the <tt>indirectbr</tt>
2656 instruction.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]2657
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2658<p>Finally, some targets may provide defined semantics when using the value as
2659 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]2660
2661</div>
2662
2663
2664<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2665<h3>
2666 <a name="constantexprs">Constant Expressions</a>
2667</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2668
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2669<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2670
2671<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2672 to be used as constants. Constant expressions may be of
2673 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2674 operation that does not have side effects (e.g. load and call are not
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]2675 supported). The following is the syntax for constant expressions:</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2676
2677<dl>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2678 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2679 <dd>Truncate a constant to another type. The bit size of CST must be larger
2680 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2681
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2682 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2683 <dd>Zero extend a constant to another type. The bit size of CST must be
Duncan Sands28afd432010-07-13 12:06:14 +0000[diff] [blame]2684 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2685
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2686 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2687 <dd>Sign extend a constant to another type. The bit size of CST must be
Duncan Sands28afd432010-07-13 12:06:14 +0000[diff] [blame]2688 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2689
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2690 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2691 <dd>Truncate a floating point constant to another floating point type. The
2692 size of CST must be larger than the size of TYPE. Both types must be
2693 floating point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2694
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2695 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2696 <dd>Floating point extend a constant to another type. The size of CST must be
2697 smaller or equal to the size of TYPE. Both types must be floating
2698 point.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2699
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2700 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2701 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2702 constant. TYPE must be a scalar or vector integer type. CST must be of
2703 scalar or vector floating point type. Both CST and TYPE must be scalars,
2704 or vectors of the same number of elements. If the value won't fit in the
2705 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2706
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2707 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2708 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2709 constant. TYPE must be a scalar or vector integer type. CST must be of
2710 scalar or vector floating point type. Both CST and TYPE must be scalars,
2711 or vectors of the same number of elements. If the value won't fit in the
2712 integer type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2713
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2714 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2715 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2716 constant. TYPE must be a scalar or vector floating point type. CST must be
2717 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2718 vectors of the same number of elements. If the value won't fit in the
2719 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2720
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2721 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2722 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2723 constant. TYPE must be a scalar or vector floating point type. CST must be
2724 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2725 vectors of the same number of elements. If the value won't fit in the
2726 floating point type, the results are undefined.</dd>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]2727
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2728 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2729 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2730 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2731 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2732 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2733
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2734 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2735 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2736 type. CST must be of integer type. The CST value is zero extended,
2737 truncated, or unchanged to make it fit in a pointer size. This one is
2738 <i>really</i> dangerous!</dd>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]2739
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2740 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner03bbad62009-02-28 18:27:03 +0000[diff] [blame]2741 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2742 are the same as those for the <a href="#i_bitcast">bitcast
2743 instruction</a>.</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2744
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2745 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2746 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2747 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2748 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2749 instruction, the index list may have zero or more indexes, which are
2750 required to make sense for the type of "CSTPTR".</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2751
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2752 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2753 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2754
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2755 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2756 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2757
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2758 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer01c42592006-12-04 19:23:19 +0000[diff] [blame]2759 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2760
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2761 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2762 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2763 constants.</dd>
Robert Bocchino9fbe1452006-01-10 19:31:34 +0000[diff] [blame]2764
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2765 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2766 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2767 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2768
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2769 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2770 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2771 constants.</dd>
Chris Lattnerc1989542006-04-08 00:13:41 +0000[diff] [blame]2772
Nick Lewycky9e130ce2010-05-29 06:44:15 +0000[diff] [blame]2773 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2774 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2775 constants. The index list is interpreted in a similar manner as indices in
2776 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2777 index value must be specified.</dd>
2778
2779 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2780 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2781 constants. The index list is interpreted in a similar manner as indices in
2782 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2783 index value must be specified.</dd>
2784
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]2785 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2786 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2787 be any of the <a href="#binaryops">binary</a>
2788 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2789 on operands are the same as those for the corresponding instruction
2790 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2791</dl>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2792
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2793</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]2794
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2795</div>
2796
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2797<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2798<h2><a name="othervalues">Other Values</a></h2>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2799<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2800<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2801<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2802<h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2803<a name="inlineasm">Inline Assembler Expressions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2804</h3>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2805
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2806<div>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2807
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2808<p>LLVM supports inline assembler expressions (as opposed
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2809 to <a href="#moduleasm">Module-Level Inline Assembly</a>) through the use of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2810 a special value. This value represents the inline assembler as a string
2811 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2812 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2813 expression has side effects, and a flag indicating whether the function
2814 containing the asm needs to align its stack conservatively. An example
2815 inline assembler expression is:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2816
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2817<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2818i32 (i32) asm "bswap $0", "=r,r"
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2819</pre>
2820
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2821<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2822 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2823 have:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2824
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2825<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2826%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2827</pre>
2828
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2829<p>Inline asms with side effects not visible in the constraint list must be
2830 marked as having side effects. This is done through the use of the
2831 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2832
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2833<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]2834call void asm sideeffect "eieio", ""()
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2835</pre>
2836
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2837<p>In some cases inline asms will contain code that will not work unless the
2838 stack is aligned in some way, such as calls or SSE instructions on x86,
2839 yet will not contain code that does that alignment within the asm.
2840 The compiler should make conservative assumptions about what the asm might
2841 contain and should generate its usual stack alignment code in the prologue
2842 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2843
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2844<pre class="doc_code">
Dale Johannesen8ba2d5b2009-10-21 23:28:00 +0000[diff] [blame]2845call void asm alignstack "eieio", ""()
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2846</pre>
Dale Johannesen09fed252009-10-13 21:56:55 +0000[diff] [blame]2847
2848<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2849 first.</p>
2850
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2851<!--
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2852<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]2853 documented here. Constraints on what can be done (e.g. duplication, moving,
2854 etc need to be documented). This is probably best done by reference to
2855 another document that covers inline asm from a holistic perspective.</p>
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2856 -->
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2857
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2858<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2859<h4>
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2860 <a name="inlineasm_md">Inline Asm Metadata</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2861</h4>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2862
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2863<div>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2864
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2865<p>The call instructions that wrap inline asm nodes may have a
2866 "<tt>!srcloc</tt>" MDNode attached to it that contains a list of constant
2867 integers. If present, the code generator will use the integer as the
2868 location cookie value when report errors through the <tt>LLVMContext</tt>
2869 error reporting mechanisms. This allows a front-end to correlate backend
2870 errors that occur with inline asm back to the source code that produced it.
2871 For example:</p>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2872
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]2873<pre class="doc_code">
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2874call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2875...
2876!42 = !{ i32 1234567 }
2877</pre>
Chris Lattnercf9a4152010-04-07 05:38:05 +0000[diff] [blame]2878
2879<p>It is up to the front-end to make sense of the magic numbers it places in the
Bill Wendlingaee0f452011-11-30 21:52:43 +0000[diff] [blame]2880 IR. If the MDNode contains multiple constants, the code generator will use
Chris Lattnerce1b9ad2010-11-17 08:20:42 +0000[diff] [blame]2881 the one that corresponds to the line of the asm that the error occurs on.</p>
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]2882
2883</div>
2884
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2885</div>
2886
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2887<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]2888<h3>
2889 <a name="metadata">Metadata Nodes and Metadata Strings</a>
2890</h3>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2891
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]2892<div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2893
2894<p>LLVM IR allows metadata to be attached to instructions in the program that
2895 can convey extra information about the code to the optimizers and code
2896 generator. One example application of metadata is source-level debug
2897 information. There are two metadata primitives: strings and nodes. All
2898 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2899 preceding exclamation point ('<tt>!</tt>').</p>
2900
2901<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2902 any character by escaping non-printable characters with "<tt>\xx</tt>" where
2903 "<tt>xx</tt>" is the two digit hex code. For example:
2904 "<tt>!"test\00"</tt>".</p>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2905
2906<p>Metadata nodes are represented with notation similar to structure constants
2907 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2908 exclamation point). Metadata nodes can have any values as their operand. For
2909 example:</p>
2910
2911<div class="doc_code">
2912<pre>
2913!{ metadata !"test\00", i32 10}
2914</pre>
2915</div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2916
2917<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2918 metadata nodes, which can be looked up in the module symbol table. For
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2919 example:</p>
2920
2921<div class="doc_code">
2922<pre>
2923!foo = metadata !{!4, !3}
2924</pre>
2925</div>
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]2926
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2927<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2928 function is using two metadata arguments:</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2929
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2930<div class="doc_code">
2931<pre>
2932call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2933</pre>
2934</div>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2935
2936<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2937 attached to the <tt>add</tt> instruction using the <tt>!dbg</tt>
2938 identifier:</p>
Devang Patele1d50cd2010-03-04 23:44:48 +0000[diff] [blame]2939
Bill Wendling9ff5de92011-03-02 02:17:11 +0000[diff] [blame]2940<div class="doc_code">
2941<pre>
2942%indvar.next = add i64 %indvar, 1, !dbg !21
2943</pre>
2944</div>
2945
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]2946<p>More information about specific metadata nodes recognized by the optimizers
2947 and code generator is found below.</p>
2948
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2949<!-- _______________________________________________________________________ -->
Peter Collingbourne249d9532011-10-27 19:19:07 +0000[diff] [blame]2950<h4>
2951 <a name="tbaa">'<tt>tbaa</tt>' Metadata</a>
2952</h4>
2953
2954<div>
2955
2956<p>In LLVM IR, memory does not have types, so LLVM's own type system is not
2957 suitable for doing TBAA. Instead, metadata is added to the IR to describe
2958 a type system of a higher level language. This can be used to implement
2959 typical C/C++ TBAA, but it can also be used to implement custom alias
2960 analysis behavior for other languages.</p>
2961
2962<p>The current metadata format is very simple. TBAA metadata nodes have up to
2963 three fields, e.g.:</p>
2964
2965<div class="doc_code">
2966<pre>
2967!0 = metadata !{ metadata !"an example type tree" }
2968!1 = metadata !{ metadata !"int", metadata !0 }
2969!2 = metadata !{ metadata !"float", metadata !0 }
2970!3 = metadata !{ metadata !"const float", metadata !2, i64 1 }
2971</pre>
2972</div>
2973
2974<p>The first field is an identity field. It can be any value, usually
2975 a metadata string, which uniquely identifies the type. The most important
2976 name in the tree is the name of the root node. Two trees with
2977 different root node names are entirely disjoint, even if they
2978 have leaves with common names.</p>
2979
2980<p>The second field identifies the type's parent node in the tree, or
2981 is null or omitted for a root node. A type is considered to alias
2982 all of its descendants and all of its ancestors in the tree. Also,
2983 a type is considered to alias all types in other trees, so that
2984 bitcode produced from multiple front-ends is handled conservatively.</p>
2985
2986<p>If the third field is present, it's an integer which if equal to 1
2987 indicates that the type is "constant" (meaning
2988 <tt>pointsToConstantMemory</tt> should return true; see
2989 <a href="AliasAnalysis.html#OtherItfs">other useful
2990 <tt>AliasAnalysis</tt> methods</a>).</p>
2991
2992</div>
2993
Bill Wendlingf6cc4c22011-11-30 21:43:43 +0000[diff] [blame]2994<!-- _______________________________________________________________________ -->
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]2995<h4>
2996 <a name="fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a>
2997</h4>
2998
2999<div>
3000
3001<p><tt>fpaccuracy</tt> metadata may be attached to any instruction of floating
3002 point type. It expresses the maximum relative error of the result of
3003 that instruction, in ULPs. ULP is defined as follows:</p>
3004
Bill Wendling0656e252011-11-09 19:33:56 +0000[diff] [blame]3005<blockquote>
3006
3007<p>If <tt>x</tt> is a real number that lies between two finite consecutive
3008 floating-point numbers <tt>a</tt> and <tt>b</tt>, without being equal to one
3009 of them, then <tt>ulp(x) = |b - a|</tt>, otherwise <tt>ulp(x)</tt> is the
3010 distance between the two non-equal finite floating-point numbers nearest
3011 <tt>x</tt>. Moreover, <tt>ulp(NaN)</tt> is <tt>NaN</tt>.</p>
3012
3013</blockquote>
Peter Collingbourne999f90b2011-10-27 19:19:14 +0000[diff] [blame]3014
3015<p>The maximum relative error may be any rational number. The metadata node
3016 shall consist of a pair of unsigned integers respectively representing
3017 the numerator and denominator. For example, 2.5 ULP:</p>
3018
3019<div class="doc_code">
3020<pre>
3021!0 = metadata !{ i32 5, i32 2 }
3022</pre>
3023</div>
3024
3025</div>
3026
Chris Lattnere6a5ddd2010-01-15 21:50:19 +0000[diff] [blame]3027</div>
3028
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3029</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3030
3031<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3032<h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3033 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3034</h2>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3035<!-- *********************************************************************** -->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3036<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3037<p>LLVM has a number of "magic" global variables that contain data that affect
3038code generation or other IR semantics. These are documented here. All globals
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3039of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
3040section and all globals that start with "<tt>llvm.</tt>" are reserved for use
3041by LLVM.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3042
3043<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3044<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3045<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3046</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3047
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3048<div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3049
3050<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
3051href="#linkage_appending">appending linkage</a>. This array contains a list of
3052pointers to global variables and functions which may optionally have a pointer
3053cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
3054
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3055<div class="doc_code">
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3056<pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3057@X = global i8 4
3058@Y = global i32 123
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3059
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3060@llvm.used = appending global [2 x i8*] [
3061 i8* @X,
3062 i8* bitcast (i32* @Y to i8*)
3063], section "llvm.metadata"
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3064</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3065</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3066
3067<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3068 compiler, assembler, and linker are required to treat the symbol as if there
3069 is a reference to the global that it cannot see. For example, if a variable
3070 has internal linkage and no references other than that from
3071 the <tt>@llvm.used</tt> list, it cannot be deleted. This is commonly used to
3072 represent references from inline asms and other things the compiler cannot
3073 "see", and corresponds to "<tt>attribute((used))</tt>" in GNU C.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3074
3075<p>On some targets, the code generator must emit a directive to the assembler or
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3076 object file to prevent the assembler and linker from molesting the
3077 symbol.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3078
3079</div>
3080
3081<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3082<h3>
3083 <a name="intg_compiler_used">
3084 The '<tt>llvm.compiler.used</tt>' Global Variable
3085 </a>
3086</h3>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3087
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3088<div>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3089
3090<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3091 <tt>@llvm.used</tt> directive, except that it only prevents the compiler from
3092 touching the symbol. On targets that support it, this allows an intelligent
3093 linker to optimize references to the symbol without being impeded as it would
3094 be by <tt>@llvm.used</tt>.</p>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3095
3096<p>This is a rare construct that should only be used in rare circumstances, and
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3097 should not be exposed to source languages.</p>
Chris Lattner401e10c2009-07-20 06:14:25 +0000[diff] [blame]3098
3099</div>
3100
3101<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3102<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3103<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3104</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3105
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3106<div>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3107
3108<div class="doc_code">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3109<pre>
3110%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3111@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3112</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3113</div>
3114
3115<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor
3116 functions and associated priorities. The functions referenced by this array
3117 will be called in ascending order of priority (i.e. lowest first) when the
3118 module is loaded. The order of functions with the same priority is not
3119 defined.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3120
3121</div>
3122
3123<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3124<h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3125<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3126</h3>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3127
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3128<div>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3129
3130<div class="doc_code">
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3131<pre>
3132%0 = type { i32, void ()* }
David Chisnall27195a52010-04-30 19:27:35 +0000[diff] [blame]3133@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalle31e9962010-04-30 19:23:49 +0000[diff] [blame]3134</pre>
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3135</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3136
Bill Wendling9ae75632011-11-08 00:32:45 +0000[diff] [blame]3137<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions
3138 and associated priorities. The functions referenced by this array will be
3139 called in descending order of priority (i.e. highest first) when the module
3140 is loaded. The order of functions with the same priority is not defined.</p>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3141
3142</div>
3143
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3144</div>
Chris Lattner857755c2009-07-20 05:55:19 +0000[diff] [blame]3145
Chris Lattnere87d6532006-01-25 23:47:57 +0000[diff] [blame]3146<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3147<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3148<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3149
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3150<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3151
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3152<p>The LLVM instruction set consists of several different classifications of
3153 instructions: <a href="#terminators">terminator
3154 instructions</a>, <a href="#binaryops">binary instructions</a>,
3155 <a href="#bitwiseops">bitwise binary instructions</a>,
3156 <a href="#memoryops">memory instructions</a>, and
3157 <a href="#otherops">other instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3158
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3159<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3160<h3>
3161 <a name="terminators">Terminator Instructions</a>
3162</h3>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3163
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3164<div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3165
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3166<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
3167 in a program ends with a "Terminator" instruction, which indicates which
3168 block should be executed after the current block is finished. These
3169 terminator instructions typically yield a '<tt>void</tt>' value: they produce
3170 control flow, not values (the one exception being the
3171 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
3172
Chris Lattner6445ecb2011-08-02 20:29:13 +0000[diff] [blame]3173<p>The terminator instructions are:
3174 '<a href="#i_ret"><tt>ret</tt></a>',
3175 '<a href="#i_br"><tt>br</tt></a>',
3176 '<a href="#i_switch"><tt>switch</tt></a>',
3177 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>',
3178 '<a href="#i_invoke"><tt>invoke</tt></a>',
3179 '<a href="#i_unwind"><tt>unwind</tt></a>',
3180 '<a href="#i_resume"><tt>resume</tt></a>', and
3181 '<a href="#i_unreachable"><tt>unreachable</tt></a>'.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]3182
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3183<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3184<h4>
3185 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3186</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3187
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3188<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3189
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3190<h5>Syntax:</h5>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3191<pre>
3192 ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3193 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3194</pre>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3195
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3196<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3197<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
3198 a value) from a function back to the caller.</p>
3199
3200<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
3201 value and then causes control flow, and one that just causes control flow to
3202 occur.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3203
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3204<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3205<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
3206 return value. The type of the return value must be a
3207 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]3208
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3209<p>A function is not <a href="#wellformed">well formed</a> if it it has a
3210 non-void return type and contains a '<tt>ret</tt>' instruction with no return
3211 value or a return value with a type that does not match its type, or if it
3212 has a void return type and contains a '<tt>ret</tt>' instruction with a
3213 return value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3214
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3215<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3216<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
3217 the calling function's context. If the caller is a
3218 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
3219 instruction after the call. If the caller was an
3220 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
3221 the beginning of the "normal" destination block. If the instruction returns
3222 a value, that value shall set the call or invoke instruction's return
3223 value.</p>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3224
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3225<h5>Example:</h5>
Chris Lattnerf4cde4e2008-04-23 04:59:35 +0000[diff] [blame]3226<pre>
3227 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]3228 ret void <i>; Return from a void function</i>
Bill Wendling0a4bbbf2009-02-28 22:12:54 +0000[diff] [blame]3229 ret { i32, i8 } { i32 4, i8 2 } <i>; Return a struct of values 4 and 2</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3230</pre>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]3231
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3232</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3233<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3234<h4>
3235 <a name="i_br">'<tt>br</tt>' Instruction</a>
3236</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3237
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3238<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3239
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3240<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3241<pre>
Bill Wendlingb3aa4712011-07-26 10:41:15 +0000[diff] [blame]3242 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
3243 br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3244</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3245
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3246<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3247<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
3248 different basic block in the current function. There are two forms of this
3249 instruction, corresponding to a conditional branch and an unconditional
3250 branch.</p>
3251
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3252<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3253<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
3254 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
3255 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
3256 target.</p>
3257
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3258<h5>Semantics:</h5>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3259<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3260 argument is evaluated. If the value is <tt>true</tt>, control flows to the
3261 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
3262 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
3263
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3264<h5>Example:</h5>
Bill Wendlingc39e3e02009-07-20 02:39:26 +0000[diff] [blame]3265<pre>
3266Test:
3267 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
3268 br i1 %cond, label %IfEqual, label %IfUnequal
3269IfEqual:
3270 <a href="#i_ret">ret</a> i32 1
3271IfUnequal:
3272 <a href="#i_ret">ret</a> i32 0
3273</pre>
3274
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3275</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3276
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3277<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3278<h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3279 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3280</h4>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3281
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3282<div>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3283
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3284<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3285<pre>
3286 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3287</pre>
3288
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3289<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3290<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3291 several different places. It is a generalization of the '<tt>br</tt>'
3292 instruction, allowing a branch to occur to one of many possible
3293 destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3294
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3295<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3296<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3297 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3298 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3299 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3300
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3301<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3302<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3303 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3304 is searched for the given value. If the value is found, control flow is
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]3305 transferred to the corresponding destination; otherwise, control flow is
3306 transferred to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3307
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3308<h5>Implementation:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3309<p>Depending on properties of the target machine and the particular
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3310 <tt>switch</tt> instruction, this instruction may be code generated in
3311 different ways. For example, it could be generated as a series of chained
3312 conditional branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3313
3314<h5>Example:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3315<pre>
3316 <i>; Emulate a conditional br instruction</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]3317 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3318 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3319
3320 <i>; Emulate an unconditional br instruction</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3321 switch i32 0, label %dest [ ]
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]3322
3323 <i>; Implement a jump table:</i>
Dan Gohman2a08c532009-01-04 23:44:43 +0000[diff] [blame]3324 switch i32 %val, label %otherwise [ i32 0, label %onzero
3325 i32 1, label %onone
3326 i32 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3327</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3328
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3329</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3330
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3331
3332<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3333<h4>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3334 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3335</h4>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3336
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3337<div>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3338
3339<h5>Syntax:</h5>
3340<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3341 indirectbr &lt;somety&gt;* &lt;address&gt;, [ label &lt;dest1&gt;, label &lt;dest2&gt;, ... ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3342</pre>
3343
3344<h5>Overview:</h5>
3345
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3346<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3347 within the current function, whose address is specified by
Chris Lattnerc6f44362009-10-27 21:01:34 +0000[diff] [blame]3348 "<tt>address</tt>". Address must be derived from a <a
3349 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3350
3351<h5>Arguments:</h5>
3352
3353<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3354 rest of the arguments indicate the full set of possible destinations that the
3355 address may point to. Blocks are allowed to occur multiple times in the
3356 destination list, though this isn't particularly useful.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3357
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3358<p>This destination list is required so that dataflow analysis has an accurate
3359 understanding of the CFG.</p>
3360
3361<h5>Semantics:</h5>
3362
3363<p>Control transfers to the block specified in the address argument. All
3364 possible destination blocks must be listed in the label list, otherwise this
3365 instruction has undefined behavior. This implies that jumps to labels
3366 defined in other functions have undefined behavior as well.</p>
3367
3368<h5>Implementation:</h5>
3369
3370<p>This is typically implemented with a jump through a register.</p>
3371
3372<h5>Example:</h5>
3373<pre>
Chris Lattnerab21db72009-10-28 00:19:10 +0000[diff] [blame]3374 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnerf9be95f2009-10-27 19:13:16 +0000[diff] [blame]3375</pre>
3376
3377</div>
3378
3379
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3380<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3381<h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3382 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3383</h4>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3384
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3385<div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3386
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3387<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3388<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3389 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ptr to function ty&gt; &lt;function ptr val&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Chris Lattner76b8a332006-05-14 18:23:06 +0000[diff] [blame]3390 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3391</pre>
3392
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]3393<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3394<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3395 function, with the possibility of control flow transfer to either the
3396 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3397 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3398 control flow will return to the "normal" label. If the callee (or any
3399 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3400 instruction, control is interrupted and continued at the dynamically nearest
3401 "exception" label.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3402
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3403<p>The '<tt>exception</tt>' label is a
3404 <i><a href="ExceptionHandling.html#overview">landing pad</a></i> for the
3405 exception. As such, '<tt>exception</tt>' label is required to have the
3406 "<a href="#i_landingpad"><tt>landingpad</tt></a>" instruction, which contains
Chad Rosier85f5a1a2011-12-09 02:00:44 +0000[diff] [blame]3407 the information about the behavior of the program after unwinding
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3408 happens, as its first non-PHI instruction. The restrictions on the
3409 "<tt>landingpad</tt>" instruction's tightly couples it to the
3410 "<tt>invoke</tt>" instruction, so that the important information contained
3411 within the "<tt>landingpad</tt>" instruction can't be lost through normal
3412 code motion.</p>
3413
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3414<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3415<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3416
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3417<ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3418 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3419 convention</a> the call should use. If none is specified, the call
3420 defaults to using C calling conventions.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3421
3422 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3423 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3424 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]3425
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3426 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3427 function value being invoked. In most cases, this is a direct function
3428 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3429 off an arbitrary pointer to function value.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3430
3431 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3432 function to be invoked. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3433
3434 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]3435 signature argument types and parameter attributes. All arguments must be
3436 of <a href="#t_firstclass">first class</a> type. If the function
3437 signature indicates the function accepts a variable number of arguments,
3438 the extra arguments can be specified.</li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3439
3440 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3441 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3442
3443 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3444 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3445
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]3446 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3447 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3448 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3449</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3450
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3451<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3452<p>This instruction is designed to operate as a standard
3453 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3454 primary difference is that it establishes an association with a label, which
3455 is used by the runtime library to unwind the stack.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3456
3457<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3458 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3459 exception. Additionally, this is important for implementation of
3460 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3461
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3462<p>For the purposes of the SSA form, the definition of the value returned by the
3463 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3464 block to the "normal" label. If the callee unwinds then no return value is
3465 available.</p>
Dan Gohmanf96a4992009-05-22 21:47:08 +0000[diff] [blame]3466
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3467<p>Note that the code generator does not yet completely support unwind, and
3468that the invoke/unwind semantics are likely to change in future versions.</p>
3469
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3470<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]3471<pre>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3472 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3473 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckyd703f652008-03-16 07:18:12 +0000[diff] [blame]3474 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3475 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3476</pre>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3477
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3478</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3479
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3480<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3481
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3482<h4>
3483 <a name="i_unwind">'<tt>unwind</tt>' Instruction</a>
3484</h4>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3485
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3486<div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3487
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3488<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3489<pre>
3490 unwind
3491</pre>
3492
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3493<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3494<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3495 at the first callee in the dynamic call stack which used
3496 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3497 This is primarily used to implement exception handling.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3498
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]3499<h5>Semantics:</h5>
Chris Lattner72ed2002008-04-19 21:01:16 +0000[diff] [blame]3500<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3501 immediately halt. The dynamic call stack is then searched for the
3502 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3503 Once found, execution continues at the "exceptional" destination block
3504 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3505 instruction in the dynamic call chain, undefined behavior results.</p>
3506
Chris Lattnerdf7a6802010-01-15 18:08:37 +0000[diff] [blame]3507<p>Note that the code generator does not yet completely support unwind, and
3508that the invoke/unwind semantics are likely to change in future versions.</p>
3509
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3510</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3511
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3512 <!-- _______________________________________________________________________ -->
3513
3514<h4>
3515 <a name="i_resume">'<tt>resume</tt>' Instruction</a>
3516</h4>
3517
3518<div>
3519
3520<h5>Syntax:</h5>
3521<pre>
3522 resume &lt;type&gt; &lt;value&gt;
3523</pre>
3524
3525<h5>Overview:</h5>
3526<p>The '<tt>resume</tt>' instruction is a terminator instruction that has no
3527 successors.</p>
3528
3529<h5>Arguments:</h5>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3530<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlinge4ad50b2011-08-03 18:37:32 +0000[diff] [blame]3531 same type as the result of any '<tt>landingpad</tt>' instruction in the same
3532 function.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3533
3534<h5>Semantics:</h5>
3535<p>The '<tt>resume</tt>' instruction resumes propagation of an existing
3536 (in-flight) exception whose unwinding was interrupted with
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3537 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3538
3539<h5>Example:</h5>
3540<pre>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]3541 resume { i8*, i32 } %exn
Bill Wendlingdccc03b2011-07-31 06:30:59 +0000[diff] [blame]3542</pre>
3543
3544</div>
3545
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3546<!-- _______________________________________________________________________ -->
3547
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3548<h4>
3549 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3550</h4>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3551
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3552<div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3553
3554<h5>Syntax:</h5>
3555<pre>
3556 unreachable
3557</pre>
3558
3559<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3560<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3561 instruction is used to inform the optimizer that a particular portion of the
3562 code is not reachable. This can be used to indicate that the code after a
3563 no-return function cannot be reached, and other facts.</p>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3564
3565<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3566<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3567
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]3568</div>
3569
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3570</div>
3571
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3572<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3573<h3>
3574 <a name="binaryops">Binary Operations</a>
3575</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3576
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3577<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3578
3579<p>Binary operators are used to do most of the computation in a program. They
3580 require two operands of the same type, execute an operation on them, and
3581 produce a single value. The operands might represent multiple data, as is
3582 the case with the <a href="#t_vector">vector</a> data type. The result value
3583 has the same type as its operands.</p>
3584
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3585<p>There are several different binary operators:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3586
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3587<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3588<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3589 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3590</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3591
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3592<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3593
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3594<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3595<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3596 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]3597 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3598 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3599 &lt;result&gt; = add nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3600</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3601
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3602<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3603<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3604
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3605<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3606<p>The two arguments to the '<tt>add</tt>' instruction must
3607 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3608 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3609
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3610<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3611<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3612
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3613<p>If the sum has unsigned overflow, the result returned is the mathematical
3614 result modulo 2<sup>n</sup>, where n is the bit width of the result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3615
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3616<p>Because LLVM integers use a two's complement representation, this instruction
3617 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3618
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3619<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3620 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3621 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3622 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3623 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3624
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3625<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3626<pre>
3627 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3628</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3629
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3630</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3631
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3632<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3633<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3634 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3635</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3636
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3637<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3638
3639<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3640<pre>
3641 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3642</pre>
3643
3644<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3645<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3646
3647<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3648<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3649 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3650 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3651
3652<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3653<p>The value produced is the floating point sum of the two operands.</p>
3654
3655<h5>Example:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3656<pre>
3657 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3658</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3659
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3660</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3661
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3662<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3663<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3664 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3665</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3666
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3667<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3668
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3669<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3670<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3671 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]3672 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3673 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3674 &lt;result&gt; = sub nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3675</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3676
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3677<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3678<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3679 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3680
3681<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3682 '<tt>neg</tt>' instruction present in most other intermediate
3683 representations.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3684
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3685<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3686<p>The two arguments to the '<tt>sub</tt>' instruction must
3687 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3688 integer values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3689
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3690<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3691<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3692
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3693<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3694 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3695 result.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3696
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3697<p>Because LLVM integers use a two's complement representation, this instruction
3698 is appropriate for both signed and unsigned integers.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3699
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3700<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3701 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3702 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3703 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3704 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3705
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3706<h5>Example:</h5>
Bill Wendlingaac388b2007-05-29 09:42:13 +0000[diff] [blame]3707<pre>
3708 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]3709 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3710</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3711
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3712</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3713
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3714<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3715<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3716 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3717</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3718
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3719<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3720
3721<h5>Syntax:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3722<pre>
3723 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3724</pre>
3725
3726<h5>Overview:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3727<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3728 operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3729
3730<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3731 '<tt>fneg</tt>' instruction present in most other intermediate
3732 representations.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3733
3734<h5>Arguments:</h5>
Bill Wendlingd9fe2982009-07-20 02:32:41 +0000[diff] [blame]3735<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3736 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3737 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3738
3739<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3740<p>The value produced is the floating point difference of the two operands.</p>
3741
3742<h5>Example:</h5>
3743<pre>
3744 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3745 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3746</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3747
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3748</div>
3749
3750<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3751<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3752 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3753</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3754
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3755<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3756
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3757<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3758<pre>
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3759 &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]3760 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3761 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3762 &lt;result&gt; = mul nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3763</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3764
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3765<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3766<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3767
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3768<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3769<p>The two arguments to the '<tt>mul</tt>' instruction must
3770 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3771 integer values. Both arguments must have identical types.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3772
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3773<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3774<p>The value produced is the integer product of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3775
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3776<p>If the result of the multiplication has unsigned overflow, the result
3777 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3778 width of the result.</p>
3779
3780<p>Because LLVM integers use a two's complement representation, and the result
3781 is the same width as the operands, this instruction returns the correct
3782 result for both signed and unsigned integers. If a full product
3783 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3784 be sign-extended or zero-extended as appropriate to the width of the full
3785 product.</p>
3786
Dan Gohman08d012e2009-07-22 22:44:56 +0000[diff] [blame]3787<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3788 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3789 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3790 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanfff6c532010-04-22 23:14:21 +0000[diff] [blame]3791 respectively, occurs.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3792
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3793<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3794<pre>
3795 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3796</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3797
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3798</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3799
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3800<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3801<h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3802 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3803</h4>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3804
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3805<div>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3806
3807<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3808<pre>
3809 &lt;result&gt; = fmul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3810</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3811
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3812<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3813<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3814
3815<h5>Arguments:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3816<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3817 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3818 floating point values. Both arguments must have identical types.</p>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3819
3820<h5>Semantics:</h5>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3821<p>The value produced is the floating point product of the two operands.</p>
3822
3823<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3824<pre>
3825 &lt;result&gt; = fmul float 4.0, %var <i>; yields {float}:result = 4.0 * %var</i>
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3826</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3827
Dan Gohmanae3a0be2009-06-04 22:49:04 +0000[diff] [blame]3828</div>
3829
3830<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3831<h4>
3832 <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
3833</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3834
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3835<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3836
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3837<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3838<pre>
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]3839 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3840 &lt;result&gt; = udiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3841</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3842
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3843<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3844<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3845
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3846<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3847<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3848 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3849 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3850
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3851<h5>Semantics:</h5>
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3852<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3853
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3854<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3855 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3856
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3857<p>Division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3858
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]3859<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3860 <tt>udiv</tt> is a <a href="#poisonvalues">poison value</a> if %op1 is not a
Chris Lattner35bda892011-02-06 21:44:57 +0000[diff] [blame]3861 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
3862
3863
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3864<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3865<pre>
3866 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3867</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3868
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3869</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3870
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3871<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3872<h4>
3873 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
3874</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3875
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3876<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3877
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3878<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3879<pre>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3880 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanfdfca792009-09-02 17:31:42 +0000[diff] [blame]3881 &lt;result&gt; = sdiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3882</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3883
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3884<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3885<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3886
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3887<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3888<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3889 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3890 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3891
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3892<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3893<p>The value produced is the signed integer quotient of the two operands rounded
3894 towards zero.</p>
3895
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3896<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3897 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3898
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3899<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3900 undefined behavior; this is a rare case, but can occur, for example, by doing
3901 a 32-bit division of -2147483648 by -1.</p>
3902
Dan Gohman9c5beed2009-07-22 00:04:19 +0000[diff] [blame]3903<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]3904 <tt>sdiv</tt> is a <a href="#poisonvalues">poison value</a> if the result would
Dan Gohman38da9272010-07-11 00:08:34 +0000[diff] [blame]3905 be rounded.</p>
Dan Gohmancbb38f22009-07-20 22:41:19 +0000[diff] [blame]3906
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3907<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3908<pre>
3909 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3910</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3911
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3912</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3913
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3914<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3915<h4>
3916 <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
3917</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3918
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3919<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3920
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3921<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3922<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3923 &lt;result&gt; = fdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3924</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3925
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3926<h5>Overview:</h5>
3927<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3928
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3929<h5>Arguments:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]3930<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3931 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3932 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3933
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3934<h5>Semantics:</h5>
Reid Spencer1628cec2006-10-26 06:15:43 +0000[diff] [blame]3935<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3936
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3937<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3938<pre>
3939 &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3940</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3941
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3942</div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3943
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3944<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3945<h4>
3946 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3947</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3948
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3949<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3950
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3951<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3952<pre>
3953 &lt;result&gt; = urem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3954</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3955
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3956<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3957<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3958 division of its two arguments.</p>
3959
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3960<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]3961<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3962 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3963 values. Both arguments must have identical types.</p>
3964
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3965<h5>Semantics:</h5>
3966<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3967 This instruction always performs an unsigned division to get the
3968 remainder.</p>
3969
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3970<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3971 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3972
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]3973<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3974
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3975<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3976<pre>
3977 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3978</pre>
3979
3980</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3981
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]3982<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3983<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3984 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]3985</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3986
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]3987<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3988
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3989<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3990<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]3991 &lt;result&gt; = srem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3992</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]3993
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]3994<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]3995<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3996 division of its two operands. This instruction can also take
3997 <a href="#t_vector">vector</a> versions of the values in which case the
3998 elements must be integers.</p>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]3999
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4000<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4001<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4002 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4003 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4004
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4005<h5>Semantics:</h5>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4006<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sandsdea3a5e2011-03-07 09:12:24 +0000[diff] [blame]4007 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
4008 <i>modulo</i> operator (where the result is either zero or has the same sign
4009 as the divisor, <tt>op2</tt>) of a value.
4010 For more information about the difference,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4011 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
4012 Math Forum</a>. For a table of how this is implemented in various languages,
4013 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
4014 Wikipedia: modulo operation</a>.</p>
4015
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4016<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4017 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
4018
Chris Lattner5ec89832008-01-28 00:36:27 +0000[diff] [blame]4019<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4020 Overflow also leads to undefined behavior; this is a rare case, but can
4021 occur, for example, by taking the remainder of a 32-bit division of
4022 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
4023 lets srem be implemented using instructions that return both the result of
4024 the division and the remainder.)</p>
4025
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4026<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4027<pre>
4028 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4029</pre>
4030
4031</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4032
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4033<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4034<h4>
4035 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
4036</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4037
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4038<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4039
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4040<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4041<pre>
4042 &lt;result&gt; = frem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4043</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4044
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4045<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4046<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
4047 its two operands.</p>
4048
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4049<h5>Arguments:</h5>
4050<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4051 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4052 floating point values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4053
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4054<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4055<p>This instruction returns the <i>remainder</i> of a division. The remainder
4056 has the same sign as the dividend.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4057
Reid Spencer0a783f72006-11-02 01:53:59 +0000[diff] [blame]4058<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4059<pre>
4060 &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4061</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4062
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4063</div>
Robert Bocchino7b81c752006-02-17 21:18:08 +0000[diff] [blame]4064
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4065</div>
4066
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4067<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4068<h3>
4069 <a name="bitwiseops">Bitwise Binary Operations</a>
4070</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4071
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4072<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4073
4074<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
4075 program. They are generally very efficient instructions and can commonly be
4076 strength reduced from other instructions. They require two operands of the
4077 same type, execute an operation on them, and produce a single value. The
4078 resulting value is the same type as its operands.</p>
4079
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4080<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4081<h4>
4082 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
4083</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4084
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4085<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4086
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4087<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4088<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4089 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4090 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4091 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4092 &lt;result&gt; = shl nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4093</pre>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4094
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4095<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4096<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
4097 a specified number of bits.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4098
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4099<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4100<p>Both arguments to the '<tt>shl</tt>' instruction must be the
4101 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
4102 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4103
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4104<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4105<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
4106 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
4107 is (statically or dynamically) negative or equal to or larger than the number
4108 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4109 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4110 shift amount in <tt>op2</tt>.</p>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4111
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4112<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4113 <a href="#poisonvalues">poison value</a> if it shifts out any non-zero bits. If
Chris Lattner66298c12011-02-09 16:44:44 +0000[diff] [blame]4114 the <tt>nsw</tt> keyword is present, then the shift produces a
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4115 <a href="#poisonvalues">poison value</a> if it shifts out any bits that disagree
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4116 with the resultant sign bit. As such, NUW/NSW have the same semantics as
4117 they would if the shift were expressed as a mul instruction with the same
4118 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
4119
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4120<h5>Example:</h5>
4121<pre>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4122 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
4123 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
4124 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4125 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4126 &lt;result&gt; = shl &lt;2 x i32&gt; &lt; i32 1, i32 1&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 2, i32 4&gt;</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4127</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4128
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4129</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4130
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4131<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4132<h4>
4133 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4134</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4135
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4136<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4137
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4138<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4139<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4140 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4141 &lt;result&gt; = lshr exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4142</pre>
4143
4144<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4145<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
4146 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4147
4148<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4149<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4150 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4151 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4152
4153<h5>Semantics:</h5>
4154<p>This instruction always performs a logical shift right operation. The most
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4155 significant bits of the result will be filled with zero bits after the shift.
4156 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
4157 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4158 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4159 shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4160
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4161<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4162 <tt>lshr</tt> is a <a href="#poisonvalues">poison value</a> if any of the bits
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4163 shifted out are non-zero.</p>
4164
4165
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4166<h5>Example:</h5>
4167<pre>
4168 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
4169 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
4170 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
4171 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4172 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4173 &lt;result&gt; = lshr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0x7FFFFFFF, i32 1&gt;</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4174</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4175
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4176</div>
4177
Reid Spencer8e11bf82007-02-02 13:57:07 +0000[diff] [blame]4178<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4179<h4>
4180 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4181</h4>
4182
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4183<div>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4184
4185<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4186<pre>
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4187 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4188 &lt;result&gt; = ashr exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4189</pre>
4190
4191<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4192<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
4193 operand shifted to the right a specified number of bits with sign
4194 extension.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4195
4196<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4197<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4198 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4199 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4200
4201<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4202<p>This instruction always performs an arithmetic shift right operation, The
4203 most significant bits of the result will be filled with the sign bit
4204 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
4205 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
4206 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
4207 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4208
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4209<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]4210 <tt>ashr</tt> is a <a href="#poisonvalues">poison value</a> if any of the bits
Chris Lattnerf067d582011-02-07 16:40:21 +0000[diff] [blame]4211 shifted out are non-zero.</p>
4212
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4213<h5>Example:</h5>
4214<pre>
4215 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
4216 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
4217 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
4218 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner6ccc2d52007-10-03 21:01:14 +0000[diff] [blame]4219 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wange9f10152008-12-09 05:46:39 +0000[diff] [blame]4220 &lt;result&gt; = ashr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 3&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 -1, i32 0&gt;</i>
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4221</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4222
Reid Spencer569f2fa2007-01-31 21:39:12 +0000[diff] [blame]4223</div>
4224
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4225<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4226<h4>
4227 <a name="i_and">'<tt>and</tt>' Instruction</a>
4228</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4229
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4230<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4231
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4232<h5>Syntax:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4233<pre>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]4234 &lt;result&gt; = and &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4235</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4236
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4237<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4238<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
4239 operands.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4240
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4241<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4242<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4243 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4244 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4245
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4246<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4247<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4248
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4249<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4250 <tbody>
4251 <tr>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4252 <th>In0</th>
4253 <th>In1</th>
4254 <th>Out</th>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4255 </tr>
4256 <tr>
4257 <td>0</td>
4258 <td>0</td>
4259 <td>0</td>
4260 </tr>
4261 <tr>
4262 <td>0</td>
4263 <td>1</td>
4264 <td>0</td>
4265 </tr>
4266 <tr>
4267 <td>1</td>
4268 <td>0</td>
4269 <td>0</td>
4270 </tr>
4271 <tr>
4272 <td>1</td>
4273 <td>1</td>
4274 <td>1</td>
4275 </tr>
4276 </tbody>
4277</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4278
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4279<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4280<pre>
4281 &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4282 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
4283 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4284</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4285</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4286<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4287<h4>
4288 <a name="i_or">'<tt>or</tt>' Instruction</a>
4289</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4290
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4291<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4292
4293<h5>Syntax:</h5>
4294<pre>
4295 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4296</pre>
4297
4298<h5>Overview:</h5>
4299<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
4300 two operands.</p>
4301
4302<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4303<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4304 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4305 values. Both arguments must have identical types.</p>
4306
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4307<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4308<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4309
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4310<table border="1" cellspacing="0" cellpadding="4">
4311 <tbody>
4312 <tr>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4313 <th>In0</th>
4314 <th>In1</th>
4315 <th>Out</th>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4316 </tr>
4317 <tr>
4318 <td>0</td>
4319 <td>0</td>
4320 <td>0</td>
4321 </tr>
4322 <tr>
4323 <td>0</td>
4324 <td>1</td>
4325 <td>1</td>
4326 </tr>
4327 <tr>
4328 <td>1</td>
4329 <td>0</td>
4330 <td>1</td>
4331 </tr>
4332 <tr>
4333 <td>1</td>
4334 <td>1</td>
4335 <td>1</td>
4336 </tr>
4337 </tbody>
4338</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4339
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4340<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4341<pre>
4342 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4343 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
4344 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4345</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4346
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4347</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4348
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4349<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4350<h4>
4351 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4352</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4353
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4354<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4355
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4356<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4357<pre>
4358 &lt;result&gt; = xor &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4359</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4360
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4361<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4362<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
4363 its two operands. The <tt>xor</tt> is used to implement the "one's
4364 complement" operation, which is the "~" operator in C.</p>
4365
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4366<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4367<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4368 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4369 values. Both arguments must have identical types.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]4370
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4371<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4372<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4373
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4374<table border="1" cellspacing="0" cellpadding="4">
4375 <tbody>
4376 <tr>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4377 <th>In0</th>
4378 <th>In1</th>
4379 <th>Out</th>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4380 </tr>
4381 <tr>
4382 <td>0</td>
4383 <td>0</td>
4384 <td>0</td>
4385 </tr>
4386 <tr>
4387 <td>0</td>
4388 <td>1</td>
4389 <td>1</td>
4390 </tr>
4391 <tr>
4392 <td>1</td>
4393 <td>0</td>
4394 <td>1</td>
4395 </tr>
4396 <tr>
4397 <td>1</td>
4398 <td>1</td>
4399 <td>0</td>
4400 </tr>
4401 </tbody>
4402</table>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4403
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4404<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4405<pre>
4406 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4407 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4408 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4409 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4410</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4411
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4412</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4413
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4414</div>
4415
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4416<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4417<h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4418 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4419</h3>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4420
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4421<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4422
4423<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4424 target-independent manner. These instructions cover the element-access and
4425 vector-specific operations needed to process vectors effectively. While LLVM
4426 does directly support these vector operations, many sophisticated algorithms
4427 will want to use target-specific intrinsics to take full advantage of a
4428 specific target.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4429
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4430<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4431<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4432 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4433</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4434
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4435<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4436
4437<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4438<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4439 &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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4440</pre>
4441
4442<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4443<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4444 from a vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4445
4446
4447<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4448<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4449 of <a href="#t_vector">vector</a> type. The second operand is an index
4450 indicating the position from which to extract the element. The index may be
4451 a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4452
4453<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4454<p>The result is a scalar of the same type as the element type of
4455 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4456 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4457 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4458
4459<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4460<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4461 &lt;result&gt; = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4462</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4463
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4464</div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4465
4466<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4467<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4468 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4469</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4470
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4471<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4472
4473<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4474<pre>
Dan Gohmanf3480b92008-05-12 23:38:42 +0000[diff] [blame]4475 &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 Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4476</pre>
4477
4478<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4479<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4480 vector at a specified index.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4481
4482<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4483<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4484 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4485 whose type must equal the element type of the first operand. The third
4486 operand is an index indicating the position at which to insert the value.
4487 The index may be a variable.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4488
4489<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4490<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4491 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4492 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4493 results are undefined.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4494
4495<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4496<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4497 &lt;result&gt; = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4498</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4499
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4500</div>
4501
4502<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4503<h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4504 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4505</h4>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4506
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4507<div>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4508
4509<h5>Syntax:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4510<pre>
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4511 &lt;result&gt; = shufflevector &lt;n x &lt;ty&gt;&gt; &lt;v1&gt;, &lt;n x &lt;ty&gt;&gt; &lt;v2&gt;, &lt;m x i32&gt; &lt;mask&gt; <i>; yields &lt;m x &lt;ty&gt;&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4512</pre>
4513
4514<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4515<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4516 from two input vectors, returning a vector with the same element type as the
4517 input and length that is the same as the shuffle mask.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4518
4519<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4520<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4521 with types that match each other. The third argument is a shuffle mask whose
4522 element type is always 'i32'. The result of the instruction is a vector
4523 whose length is the same as the shuffle mask and whose element type is the
4524 same as the element type of the first two operands.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4525
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4526<p>The shuffle mask operand is required to be a constant vector with either
4527 constant integer or undef values.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4528
4529<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4530<p>The elements of the two input vectors are numbered from left to right across
4531 both of the vectors. The shuffle mask operand specifies, for each element of
4532 the result vector, which element of the two input vectors the result element
4533 gets. The element selector may be undef (meaning "don't care") and the
4534 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4535
4536<h5>Example:</h5>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4537<pre>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4538 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4539 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4540 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4541 &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.
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4542 &lt;result&gt; = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4543 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]4544 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Mon P Wangaeb06d22008-11-10 04:46:22 +0000[diff] [blame]4545 &lt;8 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7 &gt; <i>; yields &lt;8 x i32&gt;</i>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4546</pre>
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4547
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4548</div>
Tanya Lattner09474292006-04-14 19:24:33 +0000[diff] [blame]4549
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4550</div>
4551
Chris Lattner3df241e2006-04-08 23:07:04 +0000[diff] [blame]4552<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4553<h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4554 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4555</h3>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4556
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4557<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4558
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4559<p>LLVM supports several instructions for working with
4560 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4561
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4562<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4563<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4564 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4565</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4566
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4567<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4568
4569<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4570<pre>
4571 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4572</pre>
4573
4574<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4575<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4576 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4577
4578<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4579<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4580 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4581 <a href="#t_array">array</a> type. The operands are constant indices to
4582 specify which value to extract in a similar manner as indices in a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4583 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel13242892010-12-05 20:54:38 +0000[diff] [blame]4584 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4585 <ul>
4586 <li>Since the value being indexed is not a pointer, the first index is
4587 omitted and assumed to be zero.</li>
4588 <li>At least one index must be specified.</li>
4589 <li>Not only struct indices but also array indices must be in
4590 bounds.</li>
4591 </ul>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4592
4593<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4594<p>The result is the value at the position in the aggregate specified by the
4595 index operands.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4596
4597<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4598<pre>
Gabor Greifa5b6f452009-10-28 13:14:50 +0000[diff] [blame]4599 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4600</pre>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4601
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4602</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4603
4604<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4605<h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4606 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4607</h4>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4608
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4609<div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4610
4611<h5>Syntax:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4612<pre>
Bill Wendling194229e2011-07-26 20:42:28 +0000[diff] [blame]4613 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt;, &lt;idx&gt;{, &lt;idx&gt;}* <i>; yields &lt;aggregate type&gt;</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4614</pre>
4615
4616<h5>Overview:</h5>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4617<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4618 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4619
4620<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4621<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]4622 of <a href="#t_struct">struct</a> or
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]4623 <a href="#t_array">array</a> type. The second operand is a first-class
4624 value to insert. The following operands are constant indices indicating
4625 the position at which to insert the value in a similar manner as indices in a
Frits van Bommel13242892010-12-05 20:54:38 +0000[diff] [blame]4626 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4627 value to insert must have the same type as the value identified by the
4628 indices.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4629
4630<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4631<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4632 that of <tt>val</tt> except that the value at the position specified by the
4633 indices is that of <tt>elt</tt>.</p>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4634
4635<h5>Example:</h5>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4636<pre>
Chris Lattner8645d1a2011-05-22 07:18:08 +0000[diff] [blame]4637 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4638 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
4639 %agg3 = insertvalue {i32, {float}} %agg1, float %val, 1, 0 <i>; yields {i32 1, float %val}</i>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4640</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4641
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4642</div>
4643
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4644</div>
Dan Gohmana334d5f2008-05-12 23:51:09 +0000[diff] [blame]4645
4646<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4647<h3>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]4648 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4649</h3>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4650
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4651<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4652
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4653<p>A key design point of an SSA-based representation is how it represents
4654 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez2fee2942009-10-26 23:44:29 +0000[diff] [blame]4655 very simple. This section describes how to read, write, and allocate
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4656 memory in LLVM.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4657
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4658<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4659<h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4660 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4661</h4>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4662
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4663<div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4664
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4665<h5>Syntax:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4666<pre>
Dan Gohmanf75a7d32010-05-28 01:14:11 +0000[diff] [blame]4667 &lt;result&gt; = alloca &lt;type&gt;[, &lt;ty&gt; &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4668</pre>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4669
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4670<h5>Overview:</h5>
Jeff Cohen6f1cc772007-04-22 01:17:39 +0000[diff] [blame]4671<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4672 currently executing function, to be automatically released when this function
4673 returns to its caller. The object is always allocated in the generic address
4674 space (address space zero).</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4675
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4676<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4677<p>The '<tt>alloca</tt>' instruction
4678 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4679 runtime stack, returning a pointer of the appropriate type to the program.
4680 If "NumElements" is specified, it is the number of elements allocated,
4681 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4682 specified, the value result of the allocation is guaranteed to be aligned to
4683 at least that boundary. If not specified, or if zero, the target can choose
4684 to align the allocation on any convenient boundary compatible with the
4685 type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4686
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4687<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4688
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4689<h5>Semantics:</h5>
Bill Wendling871eb0a2009-05-08 20:49:29 +0000[diff] [blame]4690<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4691 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4692 memory is automatically released when the function returns. The
4693 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4694 variables that must have an address available. When the function returns
4695 (either with the <tt><a href="#i_ret">ret</a></tt>
4696 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4697 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4698
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4699<h5>Example:</h5>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4700<pre>
Dan Gohman81e21672009-01-04 23:49:44 +0000[diff] [blame]4701 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4702 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4703 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4704 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4705</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4706
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4707</div>
Chris Lattner2cbdc452005-11-06 08:02:57 +0000[diff] [blame]4708
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]4709<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4710<h4>
4711 <a name="i_load">'<tt>load</tt>' Instruction</a>
4712</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4713
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4714<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4715
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4716<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4717<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]4718 &lt;result&gt; = load [volatile] &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4719 &lt;result&gt; = load atomic [volatile] &lt;ty&gt;* &lt;pointer&gt; [singlethread] &lt;ordering&gt;, align &lt;alignment&gt;
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4720 !&lt;index&gt; = !{ i32 1 }
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4721</pre>
4722
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4723<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4724<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4725
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4726<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4727<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4728 from which to load. The pointer must point to
4729 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4730 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4731 number or order of execution of this <tt>load</tt> with other <a
4732 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4733
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]4734<p>If the <code>load</code> is marked as <code>atomic</code>, it takes an extra
4735 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4736 argument. The <code>release</code> and <code>acq_rel</code> orderings are
4737 not valid on <code>load</code> instructions. Atomic loads produce <a
4738 href="#memorymodel">defined</a> results when they may see multiple atomic
4739 stores. The type of the pointee must be an integer type whose bit width
4740 is a power of two greater than or equal to eight and less than or equal
4741 to a target-specific size limit. <code>align</code> must be explicitly
4742 specified on atomic loads, and the load has undefined behavior if the
4743 alignment is not set to a value which is at least the size in bytes of
4744 the pointee. <code>!nontemporal</code> does not have any defined semantics
4745 for atomic loads.</p>
4746
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4747<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4748 operation (that is, the alignment of the memory address). A value of 0 or an
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4749 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4750 alignment for the target. It is the responsibility of the code emitter to
4751 ensure that the alignment information is correct. Overestimating the
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4752 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4753 produce less efficient code. An alignment of 1 is always safe.</p>
4754
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4755<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4756 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4757 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling7c78dbb2010-02-25 21:23:24 +0000[diff] [blame]4758 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4759 and code generator that this load is not expected to be reused in the cache.
4760 The code generator may select special instructions to save cache bandwidth,
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4761 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4762
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4763<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4764<p>The location of memory pointed to is loaded. If the value being loaded is of
4765 scalar type then the number of bytes read does not exceed the minimum number
4766 of bytes needed to hold all bits of the type. For example, loading an
4767 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4768 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4769 is undefined if the value was not originally written using a store of the
4770 same type.</p>
4771
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4772<h5>Examples:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4773<pre>
4774 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4775 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]4776 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4777</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4778
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4779</div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4780
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4781<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]4782<h4>
4783 <a name="i_store">'<tt>store</tt>' Instruction</a>
4784</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4785
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]4786<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4787
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4788<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4789<pre>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4790 store [volatile] &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;] <i>; yields {void}</i>
4791 store atomic [volatile] &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; [singlethread] &lt;ordering&gt;, align &lt;alignment&gt; <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4792</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4793
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4794<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]4795<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4796
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4797<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4798<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4799 and an address at which to store it. The type of the
4800 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4801 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]4802 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4803 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4804 order of execution of this <tt>store</tt> with other <a
4805 href="#volatile">volatile operations</a>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4806
Eli Friedman21006d42011-08-09 23:02:53 +0000[diff] [blame]4807<p>If the <code>store</code> is marked as <code>atomic</code>, it takes an extra
4808 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4809 argument. The <code>acquire</code> and <code>acq_rel</code> orderings aren't
4810 valid on <code>store</code> instructions. Atomic loads produce <a
4811 href="#memorymodel">defined</a> results when they may see multiple atomic
4812 stores. The type of the pointee must be an integer type whose bit width
4813 is a power of two greater than or equal to eight and less than or equal
4814 to a target-specific size limit. <code>align</code> must be explicitly
4815 specified on atomic stores, and the store has undefined behavior if the
4816 alignment is not set to a value which is at least the size in bytes of
4817 the pointee. <code>!nontemporal</code> does not have any defined semantics
4818 for atomic stores.</p>
4819
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4820<p>The optional constant "align" argument specifies the alignment of the
4821 operation (that is, the alignment of the memory address). A value of 0 or an
4822 omitted "align" argument means that the operation has the preferential
4823 alignment for the target. It is the responsibility of the code emitter to
4824 ensure that the alignment information is correct. Overestimating the
4825 alignment results in an undefined behavior. Underestimating the alignment may
4826 produce less efficient code. An alignment of 1 is always safe.</p>
4827
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4828<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]4829 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4830 value 1. The existence of the !nontemporal metatadata on the
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4831 instruction tells the optimizer and code generator that this load is
4832 not expected to be reused in the cache. The code generator may
4833 select special instructions to save cache bandwidth, such as the
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]4834 MOVNT instruction on x86.</p>
David Greene8939b0d2010-02-16 20:50:18 +0000[diff] [blame]4835
4836
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]4837<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4838<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4839 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4840 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4841 does not exceed the minimum number of bytes needed to hold all bits of the
4842 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4843 writing a value of a type like <tt>i20</tt> with a size that is not an
4844 integral number of bytes, it is unspecified what happens to the extra bits
4845 that do not belong to the type, but they will typically be overwritten.</p>
4846
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4847<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4848<pre>
4849 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8c6c72d2007-10-22 05:10:05 +0000[diff] [blame]4850 store i32 3, i32* %ptr <i>; yields {void}</i>
4851 %val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4852</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]4853
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]4854</div>
4855
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]4856<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4857<h4>
4858<a name="i_fence">'<tt>fence</tt>' Instruction</a>
4859</h4>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4860
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4861<div>
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4862
4863<h5>Syntax:</h5>
4864<pre>
4865 fence [singlethread] &lt;ordering&gt; <i>; yields {void}</i>
4866</pre>
4867
4868<h5>Overview:</h5>
4869<p>The '<tt>fence</tt>' instruction is used to introduce happens-before edges
4870between operations.</p>
4871
4872<h5>Arguments:</h5> <p>'<code>fence</code>' instructions take an <a
4873href="#ordering">ordering</a> argument which defines what
4874<i>synchronizes-with</i> edges they add. They can only be given
4875<code>acquire</code>, <code>release</code>, <code>acq_rel</code>, and
4876<code>seq_cst</code> orderings.</p>
4877
4878<h5>Semantics:</h5>
4879<p>A fence <var>A</var> which has (at least) <code>release</code> ordering
4880semantics <i>synchronizes with</i> a fence <var>B</var> with (at least)
4881<code>acquire</code> ordering semantics if and only if there exist atomic
4882operations <var>X</var> and <var>Y</var>, both operating on some atomic object
4883<var>M</var>, such that <var>A</var> is sequenced before <var>X</var>,
4884<var>X</var> modifies <var>M</var> (either directly or through some side effect
4885of a sequence headed by <var>X</var>), <var>Y</var> is sequenced before
4886<var>B</var>, and <var>Y</var> observes <var>M</var>. This provides a
4887<i>happens-before</i> dependency between <var>A</var> and <var>B</var>. Rather
4888than an explicit <code>fence</code>, one (but not both) of the atomic operations
4889<var>X</var> or <var>Y</var> might provide a <code>release</code> or
4890<code>acquire</code> (resp.) ordering constraint and still
4891<i>synchronize-with</i> the explicit <code>fence</code> and establish the
4892<i>happens-before</i> edge.</p>
4893
4894<p>A <code>fence</code> which has <code>seq_cst</code> ordering, in addition to
4895having both <code>acquire</code> and <code>release</code> semantics specified
4896above, participates in the global program order of other <code>seq_cst</code>
4897operations and/or fences.</p>
4898
4899<p>The optional "<a href="#singlethread"><code>singlethread</code></a>" argument
4900specifies that the fence only synchronizes with other fences in the same
4901thread. (This is useful for interacting with signal handlers.)</p>
4902
Eli Friedman47f35132011-07-25 23:16:38 +0000[diff] [blame]4903<h5>Example:</h5>
4904<pre>
4905 fence acquire <i>; yields {void}</i>
4906 fence singlethread seq_cst <i>; yields {void}</i>
4907</pre>
4908
4909</div>
4910
4911<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4912<h4>
4913<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
4914</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4915
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4916<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4917
4918<h5>Syntax:</h5>
4919<pre>
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4920 cmpxchg [volatile] &lt;ty&gt;* &lt;pointer&gt;, &lt;ty&gt; &lt;cmp&gt;, &lt;ty&gt; &lt;new&gt; [singlethread] &lt;ordering&gt; <i>; yields {ty}</i>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4921</pre>
4922
4923<h5>Overview:</h5>
4924<p>The '<tt>cmpxchg</tt>' instruction is used to atomically modify memory.
4925It loads a value in memory and compares it to a given value. If they are
4926equal, it stores a new value into the memory.</p>
4927
4928<h5>Arguments:</h5>
4929<p>There are three arguments to the '<code>cmpxchg</code>' instruction: an
4930address to operate on, a value to compare to the value currently be at that
4931address, and a new value to place at that address if the compared values are
4932equal. The type of '<var>&lt;cmp&gt;</var>' must be an integer type whose
4933bit width is a power of two greater than or equal to eight and less than
4934or equal to a target-specific size limit. '<var>&lt;cmp&gt;</var>' and
4935'<var>&lt;new&gt;</var>' must have the same type, and the type of
4936'<var>&lt;pointer&gt;</var>' must be a pointer to that type. If the
4937<code>cmpxchg</code> is marked as <code>volatile</code>, then the
4938optimizer is not allowed to modify the number or order of execution
4939of this <code>cmpxchg</code> with other <a href="#volatile">volatile
4940operations</a>.</p>
4941
4942<!-- FIXME: Extend allowed types. -->
4943
4944<p>The <a href="#ordering"><var>ordering</var></a> argument specifies how this
4945<code>cmpxchg</code> synchronizes with other atomic operations.</p>
4946
4947<p>The optional "<code>singlethread</code>" argument declares that the
4948<code>cmpxchg</code> is only atomic with respect to code (usually signal
4949handlers) running in the same thread as the <code>cmpxchg</code>. Otherwise the
4950cmpxchg is atomic with respect to all other code in the system.</p>
4951
4952<p>The pointer passed into cmpxchg must have alignment greater than or equal to
4953the size in memory of the operand.
4954
4955<h5>Semantics:</h5>
4956<p>The contents of memory at the location specified by the
4957'<tt>&lt;pointer&gt;</tt>' operand is read and compared to
4958'<tt>&lt;cmp&gt;</tt>'; if the read value is the equal,
4959'<tt>&lt;new&gt;</tt>' is written. The original value at the location
4960is returned.
4961
4962<p>A successful <code>cmpxchg</code> is a read-modify-write instruction for the
4963purpose of identifying <a href="#release_sequence">release sequences</a>. A
4964failed <code>cmpxchg</code> is equivalent to an atomic load with an ordering
4965parameter determined by dropping any <code>release</code> part of the
4966<code>cmpxchg</code>'s ordering.</p>
4967
4968<!--
4969FIXME: Is compare_exchange_weak() necessary? (Consider after we've done
4970optimization work on ARM.)
4971
4972FIXME: Is a weaker ordering constraint on failure helpful in practice?
4973-->
4974
4975<h5>Example:</h5>
4976<pre>
4977entry:
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4978 %orig = atomic <a href="#i_load">load</a> i32* %ptr unordered <i>; yields {i32}</i>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4979 <a href="#i_br">br</a> label %loop
4980
4981loop:
4982 %cmp = <a href="#i_phi">phi</a> i32 [ %orig, %entry ], [%old, %loop]
4983 %squared = <a href="#i_mul">mul</a> i32 %cmp, %cmp
Bill Wendling262396b2011-12-09 22:41:40 +0000[diff] [blame]4984 %old = cmpxchg i32* %ptr, i32 %cmp, i32 %squared <i>; yields {i32}</i>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4985 %success = <a href="#i_icmp">icmp</a> eq i32 %cmp, %old
4986 <a href="#i_br">br</a> i1 %success, label %done, label %loop
4987
4988done:
4989 ...
4990</pre>
4991
4992</div>
4993
4994<!-- _______________________________________________________________________ -->
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4995<h4>
4996<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
4997</h4>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]4998
NAKAMURA Takumib5bb29c2011-08-12 06:17:17 +0000[diff] [blame]4999<div>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5000
5001<h5>Syntax:</h5>
5002<pre>
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]5003 atomicrmw [volatile] &lt;operation&gt; &lt;ty&gt;* &lt;pointer&gt;, &lt;ty&gt; &lt;value&gt; [singlethread] &lt;ordering&gt; <i>; yields {ty}</i>
Eli Friedmanff030482011-07-28 21:48:00 +0000[diff] [blame]5004</pre>
5005
5006<h5>Overview:</h5>
5007<p>The '<tt>atomicrmw</tt>' instruction is used to atomically modify memory.</p>
5008
5009<h5>Arguments:</h5>
5010<p>There are three arguments to the '<code>atomicrmw</code>' instruction: an
5011operation to apply, an address whose value to modify, an argument to the
5012operation. The operation must be one of the following keywords:</p>
5013<ul>
5014 <li>xchg</li>
5015 <li>add</li>
5016 <li>sub</li>
5017 <li>and</li>
5018 <li>nand</li>
5019 <li>or</li>
5020 <li>xor</li>
5021 <li>max</li>
5022 <li>min</li>
5023 <li>umax</li>
5024 <li>umin</li>
5025</ul>
5026
5027<p>The type of '<var>&lt;value&gt;</var>' must be an integer type whose
5028bit width is a power of two greater than or equal to eight and less than
5029or equal to a target-specific size limit. The type of the
5030'<code>&lt;pointer&gt;</code>' operand must be a pointer to that type.
5031If the <code>atomicrmw</code> is marked as <code>volatile</code>, then the
5032optimizer is not allowed to modify the number or order of execution of this
5033<code>atomicrmw</code> with other <a href="#volatile">volatile
5034 operations</a>.</p>
5035
5036<!-- FIXME: Extend allowed types. -->
5037
5038<h5>Semantics:</h5>
5039<p>The contents of memory at the location specified by the
5040'<tt>&lt;pointer&gt;</tt>' operand are atomically read, modified, and written
5041back. The original value at the location is returned. The modification is
5042specified by the <var>operation</var> argument:</p>
5043
5044<ul>
5045 <li>xchg: <code>*ptr = val</code></li>
5046 <li>add: <code>*ptr = *ptr + val</code></li>
5047 <li>sub: <code>*ptr = *ptr - val</code></li>
5048 <li>and: <code>*ptr = *ptr &amp; val</code></li>
5049 <li>nand: <code>*ptr = ~(*ptr &amp; val)</code></li>
5050 <li>or: <code>*ptr = *ptr | val</code></li>
5051 <li>xor: <code>*ptr = *ptr ^ val</code></li>
5052 <li>max: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using a signed comparison)</li>
5053 <li>min: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using a signed comparison)</li>
5054 <li>umax: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5055 <li>umin: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5056</ul>
5057
5058<h5>Example:</h5>
5059<pre>
5060 %old = atomicrmw add i32* %ptr, i32 1 acquire <i>; yields {i32}</i>
5061</pre>
5062
5063</div>
5064
5065<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5066<h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5067 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5068</h4>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5069
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5070<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5071
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5072<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5073<pre>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5074 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5075 &lt;result&gt; = getelementptr inbounds &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5076 &lt;result&gt; = getelementptr &lt;ptr vector&gt; ptrval, &lt;vector index type&gt; idx
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5077</pre>
5078
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5079<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5080<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5081 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
5082 It performs address calculation only and does not access memory.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5083
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5084<h5>Arguments:</h5>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5085<p>The first argument is always a pointer or a vector of pointers,
5086 and forms the basis of the
Chris Lattnerc8eef442009-07-29 06:44:13 +0000[diff] [blame]5087 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5088 elements of the aggregate object are indexed. The interpretation of each
5089 index is dependent on the type being indexed into. The first index always
5090 indexes the pointer value given as the first argument, the second index
5091 indexes a value of the type pointed to (not necessarily the value directly
5092 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5093 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]5094 vectors, and structs. Note that subsequent types being indexed into
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5095 can never be pointers, since that would require loading the pointer before
5096 continuing calculation.</p>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5097
5098<p>The type of each index argument depends on the type it is indexing into.
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]5099 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattnerfdfeb692010-02-12 20:49:41 +0000[diff] [blame]5100 integer <b>constants</b> are allowed. When indexing into an array, pointer
5101 or vector, integers of any width are allowed, and they are not required to be
Eli Friedman266246c2011-08-12 23:37:55 +0000[diff] [blame]5102 constant. These integers are treated as signed values where relevant.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5103
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5104<p>For example, let's consider a C code fragment and how it gets compiled to
5105 LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5106
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5107<pre class="doc_code">
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5108struct RT {
5109 char A;
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5110 int B[10][20];
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5111 char C;
5112};
5113struct ST {
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5114 int X;
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5115 double Y;
5116 struct RT Z;
5117};
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5118
Chris Lattnercabc8462007-05-29 15:43:56 +0000[diff] [blame]5119int *foo(struct ST *s) {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5120 return &amp;s[1].Z.B[5][13];
5121}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5122</pre>
5123
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5124<p>The LLVM code generated by Clang is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5125
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]5126<pre class="doc_code">
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5127%struct.RT = <a href="#namedtypes">type</a> { i8, [10 x [20 x i32]], i8 }
5128%struct.ST = <a href="#namedtypes">type</a> { i32, double, %struct.RT }
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5129
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5130define i32* @foo(%struct.ST* %s) nounwind uwtable readnone optsize ssp {
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5131entry:
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5132 %arrayidx = getelementptr inbounds %struct.ST* %s, i64 1, i32 2, i32 1, i64 5, i64 13
5133 ret i32* %arrayidx
Bill Wendling2f7a8b02007-05-29 09:04:49 +0000[diff] [blame]5134}
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5135</pre>
5136
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5137<h5>Semantics:</h5>
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5138<p>In the example above, the first index is indexing into the
5139 '<tt>%struct.ST*</tt>' type, which is a pointer, yielding a
5140 '<tt>%struct.ST</tt>' = '<tt>{ i32, double, %struct.RT }</tt>' type, a
5141 structure. The second index indexes into the third element of the structure,
5142 yielding a '<tt>%struct.RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]], i8 }</tt>'
5143 type, another structure. The third index indexes into the second element of
5144 the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an array. The
5145 two dimensions of the array are subscripted into, yielding an '<tt>i32</tt>'
5146 type. The '<tt>getelementptr</tt>' instruction returns a pointer to this
5147 element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5148
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5149<p>Note that it is perfectly legal to index partially through a structure,
5150 returning a pointer to an inner element. Because of this, the LLVM code for
5151 the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5152
Bill Wendlinga3495392011-12-13 01:07:07 +0000[diff] [blame]5153<pre class="doc_code">
5154define i32* @foo(%struct.ST* %s) {
5155 %t1 = getelementptr %struct.ST* %s, i32 1 <i>; yields %struct.ST*:%t1</i>
5156 %t2 = getelementptr %struct.ST* %t1, i32 0, i32 2 <i>; yields %struct.RT*:%t2</i>
5157 %t3 = getelementptr %struct.RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
5158 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
5159 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
5160 ret i32* %t5
5161}
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5162</pre>
Chris Lattnere67a9512005-06-24 17:22:57 +0000[diff] [blame]5163
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5164<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohmanbfb056d2011-12-06 03:18:47 +0000[diff] [blame]5165 <tt>getelementptr</tt> is a <a href="#poisonvalues">poison value</a> if the
Dan Gohman27ef9972010-04-23 15:23:32 +0000[diff] [blame]5166 base pointer is not an <i>in bounds</i> address of an allocated object,
5167 or if any of the addresses that would be formed by successive addition of
5168 the offsets implied by the indices to the base address with infinitely
Eli Friedman266246c2011-08-12 23:37:55 +0000[diff] [blame]5169 precise signed arithmetic are not an <i>in bounds</i> address of that
5170 allocated object. The <i>in bounds</i> addresses for an allocated object
5171 are all the addresses that point into the object, plus the address one
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5172 byte past the end.
5173 In cases where the base is a vector of pointers the <tt>inbounds</tt> keyword
5174 applies to each of the computations element-wise. </p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5175
5176<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
Eli Friedman266246c2011-08-12 23:37:55 +0000[diff] [blame]5177 the base address with silently-wrapping two's complement arithmetic. If the
5178 offsets have a different width from the pointer, they are sign-extended or
5179 truncated to the width of the pointer. The result value of the
5180 <tt>getelementptr</tt> may be outside the object pointed to by the base
5181 pointer. The result value may not necessarily be used to access memory
5182 though, even if it happens to point into allocated storage. See the
5183 <a href="#pointeraliasing">Pointer Aliasing Rules</a> section for more
5184 information.</p>
Dan Gohmandd8004d2009-07-27 21:53:46 +0000[diff] [blame]5185
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5186<p>The getelementptr instruction is often confusing. For some more insight into
5187 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner884a9702006-08-15 00:45:58 +0000[diff] [blame]5188
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]5189<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5190<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5191 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5192 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
5193 <i>; yields i8*:vptr</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5194 %vptr = getelementptr {i32, &lt;2 x i8&gt;}* %svptr, i64 0, i32 1, i32 1
Matthijs Kooijmane49d0bc2008-10-13 13:44:15 +0000[diff] [blame]5195 <i>; yields i8*:eptr</i>
5196 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta9f805c22009-04-25 07:27:44 +0000[diff] [blame]5197 <i>; yields i32*:iptr</i>
Sanjiv Gupta16ffa802009-04-24 16:38:13 +0000[diff] [blame]5198 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5199</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5200
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5201<p>In cases where the pointer argument is a vector of pointers, only a
5202 single index may be used, and the number of vector elements has to be
5203 the same. For example: </p>
5204<pre class="doc_code">
5205 %A = getelementptr <4 x i8*> %ptrs, <4 x i64> %offsets,
5206</pre>
5207
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]5208</div>
Reid Spencer47ce1792006-11-09 21:15:49 +0000[diff] [blame]5209
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5210</div>
5211
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]5212<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5213<h3>
5214 <a name="convertops">Conversion Operations</a>
5215</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5216
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5217<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5218
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5219<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5220 which all take a single operand and a type. They perform various bit
5221 conversions on the operand.</p>
5222
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5223<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5224<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5225 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5226</h4>
5227
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5228<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5229
5230<h5>Syntax:</h5>
5231<pre>
5232 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5233</pre>
5234
5235<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5236<p>The '<tt>trunc</tt>' instruction truncates its operand to the
5237 type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5238
5239<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5240<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
5241 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5242 of the same number of integers.
5243 The bit size of the <tt>value</tt> must be larger than
5244 the bit size of the destination type, <tt>ty2</tt>.
5245 Equal sized types are not allowed.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5246
5247<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5248<p>The '<tt>trunc</tt>' instruction truncates the high order bits
5249 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
5250 source size must be larger than the destination size, <tt>trunc</tt> cannot
5251 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5252
5253<h5>Example:</h5>
5254<pre>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5255 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
5256 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
5257 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
5258 %W = trunc &lt;2 x i16&gt; &lt;i16 8, i16 7&gt; to &lt;2 x i8&gt; <i>; yields &lt;i8 8, i8 7&gt;</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5259</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5260
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5261</div>
5262
5263<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5264<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5265 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5266</h4>
5267
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5268<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5269
5270<h5>Syntax:</h5>
5271<pre>
5272 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5273</pre>
5274
5275<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5276<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5277 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5278
5279
5280<h5>Arguments:</h5>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5281<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
5282 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5283 of the same number of integers.
5284 The bit size of the <tt>value</tt> must be smaller than
5285 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5286 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5287
5288<h5>Semantics:</h5>
5289<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5290 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5291
Reid Spencerb5929522007-01-12 15:46:11 +0000[diff] [blame]5292<p>When zero extending from i1, the result will always be either 0 or 1.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5293
5294<h5>Example:</h5>
5295<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5296 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5297 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotemed9b9342011-02-20 12:37:50 +0000[diff] [blame]5298 %Z = zext &lt;2 x i16&gt; &lt;i16 8, i16 7&gt; to &lt;2 x i32&gt; <i>; yields &lt;i32 8, i32 7&gt;</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5299</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5300
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5301</div>
5302
5303<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5304<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5305 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5306</h4>
5307
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5308<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5309
5310<h5>Syntax:</h5>
5311<pre>
5312 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5313</pre>
5314
5315<h5>Overview:</h5>
5316<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
5317
5318<h5>Arguments:</h5>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5319<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
5320 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5321 of the same number of integers.
5322 The bit size of the <tt>value</tt> must be smaller than
5323 the bit size of the destination type,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5324 <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5325
5326<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5327<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
5328 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
5329 of the type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5330
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5331<p>When sign extending from i1, the extension always results in -1 or 0.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5332
5333<h5>Example:</h5>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5334<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5335 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5336 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem8c20ec52011-02-24 21:01:34 +0000[diff] [blame]5337 %Z = sext &lt;2 x i16&gt; &lt;i16 8, i16 7&gt; to &lt;2 x i32&gt; <i>; yields &lt;i32 8, i32 7&gt;</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5338</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5339
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5340</div>
5341
5342<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5343<h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5344 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5345</h4>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5346
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5347<div>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5348
5349<h5>Syntax:</h5>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5350<pre>
5351 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5352</pre>
5353
5354<h5>Overview:</h5>
5355<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5356 <tt>ty2</tt>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5357
5358<h5>Arguments:</h5>
5359<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5360 point</a> value to cast and a <a href="#t_floating">floating point</a> type
5361 to cast it to. The size of <tt>value</tt> must be larger than the size of
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5362 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5363 <i>no-op cast</i>.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5364
5365<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5366<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5367 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5368 <a href="#t_floating">floating point</a> type. If the value cannot fit
5369 within the destination type, <tt>ty2</tt>, then the results are
5370 undefined.</p>
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5371
5372<h5>Example:</h5>
5373<pre>
5374 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
5375 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
5376</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5377
Reid Spencer3fa91b02006-11-09 21:48:10 +0000[diff] [blame]5378</div>
5379
5380<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5381<h4>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5382 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5383</h4>
5384
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5385<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5386
5387<h5>Syntax:</h5>
5388<pre>
5389 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5390</pre>
5391
5392<h5>Overview:</h5>
5393<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5394 floating point value.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5395
5396<h5>Arguments:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5397<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5398 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
5399 a <a href="#t_floating">floating point</a> type to cast it to. The source
5400 type must be smaller than the destination type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5401
5402<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5403<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5404 <a href="#t_floating">floating point</a> type to a larger
5405 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
5406 used to make a <i>no-op cast</i> because it always changes bits. Use
5407 <tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5408
5409<h5>Example:</h5>
5410<pre>
Nick Lewycky5bb3ece2011-03-31 18:20:19 +0000[diff] [blame]5411 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
5412 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5413</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5414
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5415</div>
5416
5417<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5418<h4>
Reid Spencer24d6da52007-01-21 00:29:26 +0000[diff] [blame]5419 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5420</h4>
5421
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5422<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5423
5424<h5>Syntax:</h5>
5425<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5426 &lt;result&gt; = fptoui &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5427</pre>
5428
5429<h5>Overview:</h5>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5430<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5431 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5432
5433<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5434<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
5435 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5436 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5437 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5438 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5439
5440<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5441<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5442 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5443 towards zero) unsigned integer value. If the value cannot fit
5444 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5445
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5446<h5>Example:</h5>
5447<pre>
Reid Spencer1539a1c2007-07-31 14:40:14 +0000[diff] [blame]5448 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5449 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5450 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5451</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5452
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5453</div>
5454
5455<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5456<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5457 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5458</h4>
5459
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5460<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5461
5462<h5>Syntax:</h5>
5463<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5464 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5465</pre>
5466
5467<h5>Overview:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5468<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5469 <a href="#t_floating">floating point</a> <tt>value</tt> to
5470 type <tt>ty2</tt>.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5471
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5472<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5473<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
5474 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5475 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5476 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5477 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5478
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]5479<h5>Semantics:</h5>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5480<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5481 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5482 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
5483 the results are undefined.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5484
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]5485<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5486<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]5487 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner88519042007-09-22 03:17:52 +0000[diff] [blame]5488 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5489 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5490</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5491
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5492</div>
5493
5494<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5495<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5496 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5497</h4>
5498
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5499<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5500
5501<h5>Syntax:</h5>
5502<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5503 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5504</pre>
5505
5506<h5>Overview:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5507<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5508 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5509
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5510<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5511<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5512 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5513 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5514 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5515 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5516
5517<h5>Semantics:</h5>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5518<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5519 integer quantity and converts it to the corresponding floating point
5520 value. If the value cannot fit in the floating point value, the results are
5521 undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5522
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5523<h5>Example:</h5>
5524<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5525 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5526 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5527</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5528
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5529</div>
5530
5531<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5532<h4>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5533 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5534</h4>
5535
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5536<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5537
5538<h5>Syntax:</h5>
5539<pre>
Reid Spencerd4448792006-11-09 23:03:26 +0000[diff] [blame]5540 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5541</pre>
5542
5543<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5544<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
5545 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5546
5547<h5>Arguments:</h5>
Nate Begemanb348d182007-11-17 03:58:34 +0000[diff] [blame]5548<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5549 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5550 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5551 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5552 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5553
5554<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5555<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
5556 quantity and converts it to the corresponding floating point value. If the
5557 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5558
5559<h5>Example:</h5>
5560<pre>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5561 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5562 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5563</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5564
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5565</div>
5566
5567<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5568<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5569 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5570</h4>
5571
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5572<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5573
5574<h5>Syntax:</h5>
5575<pre>
5576 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5577</pre>
5578
5579<h5>Overview:</h5>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5580<p>The '<tt>ptrtoint</tt>' instruction converts the pointer or a vector of
5581 pointers <tt>value</tt> to
5582 the integer (or vector of integers) type <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5583
5584<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5585<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5586 must be a a value of type <a href="#t_pointer">pointer</a> or a vector of
5587 pointers, and a type to cast it to
5588 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> or a vector
5589 of integers type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5590
5591<h5>Semantics:</h5>
5592<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5593 <tt>ty2</tt> by interpreting the pointer value as an integer and either
5594 truncating or zero extending that value to the size of the integer type. If
5595 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
5596 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
5597 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
5598 change.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5599
5600<h5>Example:</h5>
5601<pre>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5602 %X = ptrtoint i32* %P to i8 <i>; yields truncation on 32-bit architecture</i>
5603 %Y = ptrtoint i32* %P to i64 <i>; yields zero extension on 32-bit architecture</i>
5604 %Z = ptrtoint &lt;4 x i32*&gt; %P to &lt;4 x i64&gt;<i>; yields vector zero extension for a vector of addresses on 32-bit architecture</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5605</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5606
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5607</div>
5608
5609<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5610<h4>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5611 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5612</h4>
5613
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5614<div>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5615
5616<h5>Syntax:</h5>
5617<pre>
5618 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5619</pre>
5620
5621<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5622<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
5623 pointer type, <tt>ty2</tt>.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5624
5625<h5>Arguments:</h5>
Duncan Sands8036ca42007-03-30 12:22:09 +0000[diff] [blame]5626<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5627 value to cast, and a type to cast it to, which must be a
5628 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5629
5630<h5>Semantics:</h5>
5631<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5632 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
5633 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
5634 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
5635 than the size of a pointer then a zero extension is done. If they are the
5636 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5637
5638<h5>Example:</h5>
5639<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5640 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
Gabor Greif6a292012009-10-28 09:21:30 +0000[diff] [blame]5641 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
5642 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5643 %Z = inttoptr &lt;4 x i32&gt; %G to &lt;4 x i8*&gt;<i>; yields truncation of vector G to four pointers</i>
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5644</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5645
Reid Spencer72679252006-11-11 21:00:47 +0000[diff] [blame]5646</div>
5647
5648<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5649<h4>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5650 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5651</h4>
5652
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5653<div>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5654
5655<h5>Syntax:</h5>
5656<pre>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5657 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5658</pre>
5659
5660<h5>Overview:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5661<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5662 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5663
5664<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5665<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5666 non-aggregate first class value, and a type to cast it to, which must also be
5667 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5668 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5669 identical. If the source type is a pointer, the destination type must also be
5670 a pointer. This instruction supports bitwise conversion of vectors to
5671 integers and to vectors of other types (as long as they have the same
5672 size).</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5673
5674<h5>Semantics:</h5>
Reid Spencer5c0ef472006-11-11 23:08:07 +0000[diff] [blame]5675<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5676 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5677 this conversion. The conversion is done as if the <tt>value</tt> had been
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5678 stored to memory and read back as type <tt>ty2</tt>.
5679 Pointer (or vector of pointers) types may only be converted to other pointer
5680 (or vector of pointers) types with this instruction. To convert
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5681 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5682 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer9dee3ac2006-11-08 01:11:31 +0000[diff] [blame]5683
5684<h5>Example:</h5>
5685<pre>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5686 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5687 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5688 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
5689 %Z = bitcast &lt;2 x i32*&gt; %V to &lt;2 x i64*&gt; <i>; yields &lt;2 x i64*&gt;</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]5690</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5691
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]5692</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5693
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5694</div>
5695
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5696<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5697<h3>
5698 <a name="otherops">Other Operations</a>
5699</h3>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5700
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5701<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5702
5703<p>The instructions in this category are the "miscellaneous" instructions, which
5704 defy better classification.</p>
5705
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5706<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5707<h4>
5708 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5709</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5710
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5711<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5712
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5713<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5714<pre>
5715 &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5716</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5717
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5718<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5719<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
Nadav Rotem16087692011-12-05 06:29:09 +0000[diff] [blame]5720 boolean values based on comparison of its two integer, integer vector,
5721 pointer, or pointer vector operands.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5722
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5723<h5>Arguments:</h5>
5724<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5725 the condition code indicating the kind of comparison to perform. It is not a
5726 value, just a keyword. The possible condition code are:</p>
5727
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5728<ol>
5729 <li><tt>eq</tt>: equal</li>
5730 <li><tt>ne</tt>: not equal </li>
5731 <li><tt>ugt</tt>: unsigned greater than</li>
5732 <li><tt>uge</tt>: unsigned greater or equal</li>
5733 <li><tt>ult</tt>: unsigned less than</li>
5734 <li><tt>ule</tt>: unsigned less or equal</li>
5735 <li><tt>sgt</tt>: signed greater than</li>
5736 <li><tt>sge</tt>: signed greater or equal</li>
5737 <li><tt>slt</tt>: signed less than</li>
5738 <li><tt>sle</tt>: signed less or equal</li>
5739</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5740
Chris Lattner3b19d652007-01-15 01:54:13 +0000[diff] [blame]5741<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5742 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5743 typed. They must also be identical types.</p>
5744
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5745<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5746<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5747 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5748 either an <a href="#t_integer"><tt>i1</tt></a> or vector of <tt>i1</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5749 result, as follows:</p>
5750
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5751<ol>
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5752 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5753 <tt>false</tt> otherwise. No sign interpretation is necessary or
5754 performed.</li>
5755
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5756 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5757 <tt>false</tt> otherwise. No sign interpretation is necessary or
5758 performed.</li>
5759
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5760 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5761 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5762
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5763 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5764 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5765 to <tt>op2</tt>.</li>
5766
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5767 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5768 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5769
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5770 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5771 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5772
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5773 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5774 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5775
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5776 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5777 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5778 to <tt>op2</tt>.</li>
5779
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5780 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5781 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5782
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5783 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5784 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5785</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5786
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5787<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5788 values are compared as if they were integers.</p>
5789
5790<p>If the operands are integer vectors, then they are compared element by
5791 element. The result is an <tt>i1</tt> vector with the same number of elements
5792 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5793
5794<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5795<pre>
5796 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]5797 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5798 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5799 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5800 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5801 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5802</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5803
5804<p>Note that the code generator does not yet support vector types with
5805 the <tt>icmp</tt> instruction.</p>
5806
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5807</div>
5808
5809<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5810<h4>
5811 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5812</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5813
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5814<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5815
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5816<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5817<pre>
5818 &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5819</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5820
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5821<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5822<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5823 values based on comparison of its operands.</p>
5824
5825<p>If the operands are floating point scalars, then the result type is a boolean
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5826(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5827
5828<p>If the operands are floating point vectors, then the result type is a vector
5829 of boolean with the same number of elements as the operands being
5830 compared.</p>
5831
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5832<h5>Arguments:</h5>
5833<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5834 the condition code indicating the kind of comparison to perform. It is not a
5835 value, just a keyword. The possible condition code are:</p>
5836
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5837<ol>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5838 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5839 <li><tt>oeq</tt>: ordered and equal</li>
5840 <li><tt>ogt</tt>: ordered and greater than </li>
5841 <li><tt>oge</tt>: ordered and greater than or equal</li>
5842 <li><tt>olt</tt>: ordered and less than </li>
5843 <li><tt>ole</tt>: ordered and less than or equal</li>
5844 <li><tt>one</tt>: ordered and not equal</li>
5845 <li><tt>ord</tt>: ordered (no nans)</li>
5846 <li><tt>ueq</tt>: unordered or equal</li>
5847 <li><tt>ugt</tt>: unordered or greater than </li>
5848 <li><tt>uge</tt>: unordered or greater than or equal</li>
5849 <li><tt>ult</tt>: unordered or less than </li>
5850 <li><tt>ule</tt>: unordered or less than or equal</li>
5851 <li><tt>une</tt>: unordered or not equal</li>
5852 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5853 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5854</ol>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5855
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5856<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5857 <i>unordered</i> means that either operand may be a QNAN.</p>
5858
5859<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5860 a <a href="#t_floating">floating point</a> type or
5861 a <a href="#t_vector">vector</a> of floating point type. They must have
5862 identical types.</p>
5863
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5864<h5>Semantics:</h5>
Gabor Greiffb224a22008-08-07 21:46:00 +0000[diff] [blame]5865<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5866 according to the condition code given as <tt>cond</tt>. If the operands are
5867 vectors, then the vectors are compared element by element. Each comparison
Nick Lewyckyec38da42009-09-27 00:45:11 +0000[diff] [blame]5868 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5869 follows:</p>
5870
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5871<ol>
5872 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5873
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5874 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5875 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5876
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5877 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]5878 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5879
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5880 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5881 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5882
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5883 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5884 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5885
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5886 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5887 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5888
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5889 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5890 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5891
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5892 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5893
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5894 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5895 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5896
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5897 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5898 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5899
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5900 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5901 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5902
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5903 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5904 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5905
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5906 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5907 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5908
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]5909 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5910 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5911
Reid Spencerb7f26282006-11-19 03:00:14 +0000[diff] [blame]5912 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5913
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5914 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5915</ol>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5916
5917<h5>Example:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5918<pre>
5919 &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5920 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5921 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5922 &lt;result&gt; = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5923</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]5924
5925<p>Note that the code generator does not yet support vector types with
5926 the <tt>fcmp</tt> instruction.</p>
5927
Reid Spencerf3a70a62006-11-18 21:50:54 +0000[diff] [blame]5928</div>
5929
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5930<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5931<h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5932 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5933</h4>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5934
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5935<div>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5936
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5937<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5938<pre>
5939 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5940</pre>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5941
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5942<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5943<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5944 SSA graph representing the function.</p>
5945
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5946<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5947<p>The type of the incoming values is specified with the first type field. After
5948 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5949 one pair for each predecessor basic block of the current block. Only values
5950 of <a href="#t_firstclass">first class</a> type may be used as the value
5951 arguments to the PHI node. Only labels may be used as the label
5952 arguments.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5953
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5954<p>There must be no non-phi instructions between the start of a basic block and
5955 the PHI instructions: i.e. PHI instructions must be first in a basic
5956 block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5957
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5958<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5959 occur on the edge from the corresponding predecessor block to the current
5960 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5961 value on the same edge).</p>
Jay Foadd2449092009-06-03 10:20:10 +0000[diff] [blame]5962
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5963<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]5964<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5965 specified by the pair corresponding to the predecessor basic block that
5966 executed just prior to the current block.</p>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5967
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5968<h5>Example:</h5>
Chris Lattner5568e942008-05-20 20:48:21 +0000[diff] [blame]5969<pre>
5970Loop: ; Infinite loop that counts from 0 on up...
5971 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5972 %nextindvar = add i32 %indvar, 1
5973 br label %Loop
5974</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5975
Reid Spencer2fd21e62006-11-08 01:18:52 +0000[diff] [blame]5976</div>
5977
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5978<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5979<h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5980 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]5981</h4>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5982
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]5983<div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5984
5985<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5986<pre>
Dan Gohmanf72fb672008-09-09 01:02:47 +0000[diff] [blame]5987 &lt;result&gt; = select <i>selty</i> &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
5988
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]5989 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5990</pre>
5991
5992<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5993<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5994 condition, without branching.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]5995
5996
5997<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]5998<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5999 values indicating the condition, and two values of the
6000 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
6001 vectors and the condition is a scalar, then entire vectors are selected, not
6002 individual elements.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6003
6004<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6005<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
6006 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6007
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6008<p>If the condition is a vector of i1, then the value arguments must be vectors
6009 of the same size, and the selection is done element by element.</p>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6010
6011<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6012<pre>
Reid Spencerc78f3372007-01-12 03:35:51 +0000[diff] [blame]6013 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6014</pre>
Dan Gohmanc766f722009-01-22 01:39:38 +0000[diff] [blame]6015
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]6016</div>
6017
Robert Bocchino05ccd702006-01-15 20:48:27 +0000[diff] [blame]6018<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6019<h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6020 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6021</h4>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6022
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6023<div>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6024
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6025<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6026<pre>
Devang Patel307e8ab2008-10-07 17:48:33 +0000[diff] [blame]6027 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ty&gt; [&lt;fnty&gt;*] &lt;fnptrval&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6028</pre>
6029
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6030<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6031<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6032
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6033<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6034<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6035
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]6036<ol>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6037 <li>The optional "tail" marker indicates that the callee function does not
6038 access any allocas or varargs in the caller. Note that calls may be
6039 marked "tail" even if they do not occur before
6040 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
6041 present, the function call is eligible for tail call optimization,
6042 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengdc444e92010-03-08 21:05:02 +0000[diff] [blame]6043 optimized into a jump</a>. The code generator may optimize calls marked
6044 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
6045 sibling call optimization</a> when the caller and callee have
6046 matching signatures, or 2) forced tail call optimization when the
6047 following extra requirements are met:
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6048 <ul>
6049 <li>Caller and callee both have the calling
6050 convention <tt>fastcc</tt>.</li>
6051 <li>The call is in tail position (ret immediately follows call and ret
6052 uses value of call or is void).</li>
6053 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohmanfbbee8d2010-03-02 01:08:11 +0000[diff] [blame]6054 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6055 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
6056 constraints are met.</a></li>
6057 </ul>
6058 </li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6059
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6060 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
6061 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin95fa80a2010-01-09 19:44:16 +0000[diff] [blame]6062 defaults to using C calling conventions. The calling convention of the
6063 call must match the calling convention of the target function, or else the
6064 behavior is undefined.</li>
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6065
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6066 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
6067 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
6068 '<tt>inreg</tt>' attributes are valid here.</li>
6069
6070 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
6071 type of the return value. Functions that return no value are marked
6072 <tt><a href="#t_void">void</a></tt>.</li>
6073
6074 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
6075 being invoked. The argument types must match the types implied by this
6076 signature. This type can be omitted if the function is not varargs and if
6077 the function type does not return a pointer to a function.</li>
6078
6079 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
6080 be invoked. In most cases, this is a direct function invocation, but
6081 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
6082 to function value.</li>
6083
6084 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner0724fbd2010-03-02 06:36:51 +0000[diff] [blame]6085 signature argument types and parameter attributes. All arguments must be
6086 of <a href="#t_firstclass">first class</a> type. If the function
6087 signature indicates the function accepts a variable number of arguments,
6088 the extra arguments can be specified.</li>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6089
6090 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
6091 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
6092 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]6093</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6094
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6095<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6096<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
6097 a specified function, with its incoming arguments bound to the specified
6098 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
6099 function, control flow continues with the instruction after the function
6100 call, and the return value of the function is bound to the result
6101 argument.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6102
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]6103<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6104<pre>
Nick Lewyckydb7e3c92007-09-08 13:57:50 +0000[diff] [blame]6105 %retval = call i32 @test(i32 %argc)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6106 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner772fccf2008-03-21 17:24:17 +0000[diff] [blame]6107 %X = tail call i32 @foo() <i>; yields i32</i>
6108 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
6109 call void %foo(i8 97 signext)
Devang Patelc3fc6df2008-03-10 20:49:15 +0000[diff] [blame]6110
6111 %struct.A = type { i32, i8 }
Devang Patelf642f472008-10-06 18:50:38 +0000[diff] [blame]6112 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmanb1e6b962008-10-04 19:00:07 +0000[diff] [blame]6113 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
6114 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner85a350f2008-10-08 06:26:11 +0000[diff] [blame]6115 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmancb73d192008-10-07 10:03:45 +0000[diff] [blame]6116 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]6117</pre>
6118
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6119<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen9f8380b2009-09-25 17:04:42 +0000[diff] [blame]6120standard C99 library as being the C99 library functions, and may perform
6121optimizations or generate code for them under that assumption. This is
6122something we'd like to change in the future to provide better support for
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6123freestanding environments and non-C-based languages.</p>
Dale Johannesen07de8d12009-09-24 18:38:21 +0000[diff] [blame]6124
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6125</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6126
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6127<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6128<h4>
Chris Lattnerfb6977d2006-01-13 23:26:01 +0000[diff] [blame]6129 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6130</h4>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6131
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6132<div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6133
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6134<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6135<pre>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6136 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6137</pre>
6138
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6139<h5>Overview:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6140<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6141 the "variable argument" area of a function call. It is used to implement the
6142 <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6143
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6144<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6145<p>This instruction takes a <tt>va_list*</tt> value and the type of the
6146 argument. It returns a value of the specified argument type and increments
6147 the <tt>va_list</tt> to point to the next argument. The actual type
6148 of <tt>va_list</tt> is target specific.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6149
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6150<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6151<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
6152 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
6153 to the next argument. For more information, see the variable argument
6154 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6155
6156<p>It is legal for this instruction to be called in a function which does not
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6157 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6158 function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6159
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6160<p><tt>va_arg</tt> is an LLVM instruction instead of
6161 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
6162 argument.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6163
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]6164<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]6165<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6166
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6167<p>Note that the code generator does not yet fully support va_arg on many
6168 targets. Also, it does not currently support va_arg with aggregate types on
6169 any target.</p>
Dan Gohmanf3e60bd2009-01-12 23:12:39 +0000[diff] [blame]6170
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6171</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6172
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6173<!-- _______________________________________________________________________ -->
6174<h4>
6175 <a name="i_landingpad">'<tt>landingpad</tt>' Instruction</a>
6176</h4>
6177
6178<div>
6179
6180<h5>Syntax:</h5>
6181<pre>
Bill Wendlingbf13ee12011-08-08 08:06:05 +0000[diff] [blame]6182 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
6183 &lt;resultval&gt; = landingpad &lt;somety&gt; personality &lt;type&gt; &lt;pers_fn&gt; cleanup &lt;clause&gt;*
6184
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6185 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6186 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6187</pre>
6188
6189<h5>Overview:</h5>
6190<p>The '<tt>landingpad</tt>' instruction is used by
6191 <a href="ExceptionHandling.html#overview">LLVM's exception handling
6192 system</a> to specify that a basic block is a landing pad &mdash; one where
6193 the exception lands, and corresponds to the code found in the
6194 <i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
6195 defines values supplied by the personality function (<tt>pers_fn</tt>) upon
6196 re-entry to the function. The <tt>resultval</tt> has the
6197 type <tt>somety</tt>.</p>
6198
6199<h5>Arguments:</h5>
6200<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
6201 function associated with the unwinding mechanism. The optional
6202 <tt>cleanup</tt> flag indicates that the landing pad block is a cleanup.</p>
6203
6204<p>A <tt>clause</tt> begins with the clause type &mdash; <tt>catch</tt>
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6205 or <tt>filter</tt> &mdash; and contains the global variable representing the
6206 "type" that may be caught or filtered respectively. Unlike the
6207 <tt>catch</tt> clause, the <tt>filter</tt> clause takes an array constant as
6208 its argument. Use "<tt>[0 x i8**] undef</tt>" for a filter which cannot
6209 throw. The '<tt>landingpad</tt>' instruction must contain <em>at least</em>
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6210 one <tt>clause</tt> or the <tt>cleanup</tt> flag.</p>
6211
6212<h5>Semantics:</h5>
6213<p>The '<tt>landingpad</tt>' instruction defines the values which are set by the
6214 personality function (<tt>pers_fn</tt>) upon re-entry to the function, and
6215 therefore the "result type" of the <tt>landingpad</tt> instruction. As with
6216 calling conventions, how the personality function results are represented in
6217 LLVM IR is target specific.</p>
6218
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6219<p>The clauses are applied in order from top to bottom. If two
6220 <tt>landingpad</tt> instructions are merged together through inlining, the
Bill Wendling2905c322011-08-08 07:58:58 +0000[diff] [blame]6221 clauses from the calling function are appended to the list of clauses.</p>
Bill Wendlingb7a01352011-08-03 17:17:06 +0000[diff] [blame]6222
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6223<p>The <tt>landingpad</tt> instruction has several restrictions:</p>
6224
6225<ul>
6226 <li>A landing pad block is a basic block which is the unwind destination of an
6227 '<tt>invoke</tt>' instruction.</li>
6228 <li>A landing pad block must have a '<tt>landingpad</tt>' instruction as its
6229 first non-PHI instruction.</li>
6230 <li>There can be only one '<tt>landingpad</tt>' instruction within the landing
6231 pad block.</li>
6232 <li>A basic block that is not a landing pad block may not include a
6233 '<tt>landingpad</tt>' instruction.</li>
6234 <li>All '<tt>landingpad</tt>' instructions in a function must have the same
6235 personality function.</li>
6236</ul>
6237
6238<h5>Example:</h5>
6239<pre>
6240 ;; A landing pad which can catch an integer.
6241 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6242 catch i8** @_ZTIi
6243 ;; A landing pad that is a cleanup.
6244 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6245 cleanup
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6246 ;; A landing pad which can catch an integer and can only throw a double.
6247 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6248 catch i8** @_ZTIi
Bill Wendlinge6e88262011-08-12 20:24:12 +0000[diff] [blame]6249 filter [1 x i8**] [@_ZTId]
Bill Wendlingf78faf82011-08-02 21:52:38 +0000[diff] [blame]6250</pre>
6251
6252</div>
6253
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6254</div>
6255
6256</div>
6257
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6258<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6259<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]6260<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6261
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6262<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6263
6264<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6265 well known names and semantics and are required to follow certain
6266 restrictions. Overall, these intrinsics represent an extension mechanism for
6267 the LLVM language that does not require changing all of the transformations
6268 in LLVM when adding to the language (or the bitcode reader/writer, the
6269 parser, etc...).</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6270
John Criswellfc6b8952005-05-16 16:17:45 +0000[diff] [blame]6271<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6272 prefix is reserved in LLVM for intrinsic names; thus, function names may not
6273 begin with this prefix. Intrinsic functions must always be external
6274 functions: you cannot define the body of intrinsic functions. Intrinsic
6275 functions may only be used in call or invoke instructions: it is illegal to
6276 take the address of an intrinsic function. Additionally, because intrinsic
6277 functions are part of the LLVM language, it is required if any are added that
6278 they be documented here.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6279
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6280<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
6281 family of functions that perform the same operation but on different data
6282 types. Because LLVM can represent over 8 million different integer types,
6283 overloading is used commonly to allow an intrinsic function to operate on any
6284 integer type. One or more of the argument types or the result type can be
6285 overloaded to accept any integer type. Argument types may also be defined as
6286 exactly matching a previous argument's type or the result type. This allows
6287 an intrinsic function which accepts multiple arguments, but needs all of them
6288 to be of the same type, to only be overloaded with respect to a single
6289 argument or the result.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6290
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6291<p>Overloaded intrinsics will have the names of its overloaded argument types
6292 encoded into its function name, each preceded by a period. Only those types
6293 which are overloaded result in a name suffix. Arguments whose type is matched
6294 against another type do not. For example, the <tt>llvm.ctpop</tt> function
6295 can take an integer of any width and returns an integer of exactly the same
6296 integer width. This leads to a family of functions such as
6297 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
6298 %val)</tt>. Only one type, the return type, is overloaded, and only one type
6299 suffix is required. Because the argument's type is matched against the return
6300 type, it does not require its own name suffix.</p>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]6301
Eric Christopher6c7e8a02009-12-05 02:46:03 +0000[diff] [blame]6302<p>To learn how to add an intrinsic function, please see the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6303 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6304
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6305<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6306<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6307 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6308</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6309
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6310<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6311
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6312<p>Variable argument support is defined in LLVM with
6313 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
6314 intrinsic functions. These functions are related to the similarly named
6315 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6316
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6317<p>All of these functions operate on arguments that use a target-specific value
6318 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
6319 not define what this type is, so all transformations should be prepared to
6320 handle these functions regardless of the type used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6321
Chris Lattner374ab302006-05-15 17:26:46 +0000[diff] [blame]6322<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6323 instruction and the variable argument handling intrinsic functions are
6324 used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6325
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]6326<pre class="doc_code">
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6327define i32 @test(i32 %X, ...) {
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6328 ; Initialize variable argument processing
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6329 %ap = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6330 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6331 call void @llvm.va_start(i8* %ap2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6332
6333 ; Read a single integer argument
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6334 %tmp = va_arg i8** %ap, i32
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6335
6336 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6337 %aq = alloca i8*
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6338 %aq2 = bitcast i8** %aq to i8*
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6339 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6340 call void @llvm.va_end(i8* %aq2)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6341
6342 ; Stop processing of arguments.
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6343 call void @llvm.va_end(i8* %ap2)
Reid Spencerca86e162006-12-31 07:07:53 +0000[diff] [blame]6344 ret i32 %tmp
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6345}
Anton Korobeynikov5d522f32007-03-21 23:58:04 +0000[diff] [blame]6346
6347declare void @llvm.va_start(i8*)
6348declare void @llvm.va_copy(i8*, i8*)
6349declare void @llvm.va_end(i8*)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6350</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6351
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6352<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6353<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6354 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6355</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6356
6357
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6358<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6359
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6360<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6361<pre>
6362 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6363</pre>
6364
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6365<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6366<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
6367 for subsequent use by <tt><a href="#i_va_arg">va_arg</a></tt>.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6368
6369<h5>Arguments:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6370<p>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6371
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6372<h5>Semantics:</h5>
Dan Gohman0e451ce2008-10-14 16:51:45 +0000[diff] [blame]6373<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6374 macro available in C. In a target-dependent way, it initializes
6375 the <tt>va_list</tt> element to which the argument points, so that the next
6376 call to <tt>va_arg</tt> will produce the first variable argument passed to
6377 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
6378 need to know the last argument of the function as the compiler can figure
6379 that out.</p>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6380
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6381</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6382
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6383<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6384<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6385 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6386</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6387
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6388<div>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6389
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6390<h5>Syntax:</h5>
6391<pre>
6392 declare void @llvm.va_end(i8* &lt;arglist&gt;)
6393</pre>
6394
6395<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6396<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6397 which has been initialized previously
6398 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
6399 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6400
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6401<h5>Arguments:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6402<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6403
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6404<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6405<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6406 macro available in C. In a target-dependent way, it destroys
6407 the <tt>va_list</tt> element to which the argument points. Calls
6408 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
6409 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
6410 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerb75137d2007-01-08 07:55:15 +0000[diff] [blame]6411
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6412</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6413
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6414<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6415<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6416 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6417</h4>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6418
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6419<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6420
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6421<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6422<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6423 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6424</pre>
6425
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6426<h5>Overview:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6427<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6428 from the source argument list to the destination argument list.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6429
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6430<h5>Arguments:</h5>
Andrew Lenharth8bf607a2005-06-18 18:28:17 +0000[diff] [blame]6431<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6432 The second argument is a pointer to a <tt>va_list</tt> element to copy
6433 from.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6434
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]6435<h5>Semantics:</h5>
Jeff Cohenb627eab2007-04-29 01:07:00 +0000[diff] [blame]6436<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6437 macro available in C. In a target-dependent way, it copies the
6438 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
6439 element. This intrinsic is necessary because
6440 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
6441 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6442
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]6443</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]6444
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6445</div>
6446
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6447<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6448<h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6449 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6450</h3>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6451
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6452<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6453
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6454<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattnerd3eda892008-08-05 18:29:16 +0000[diff] [blame]6455Collection</a> (GC) requires the implementation and generation of these
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6456intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
6457roots on the stack</a>, as well as garbage collector implementations that
6458require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
6459barriers. Front-ends for type-safe garbage collected languages should generate
6460these intrinsics to make use of the LLVM garbage collectors. For more details,
6461see <a href="GarbageCollection.html">Accurate Garbage Collection with
6462LLVM</a>.</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6463
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6464<p>The garbage collection intrinsics only operate on objects in the generic
6465 address space (address space zero).</p>
Christopher Lamb303dae92007-12-17 01:00:21 +0000[diff] [blame]6466
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6467<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6468<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6469 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6470</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6471
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6472<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6473
6474<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6475<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6476 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6477</pre>
6478
6479<h5>Overview:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]6480<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6481 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6482
6483<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6484<p>The first argument specifies the address of a stack object that contains the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6485 root pointer. The second pointer (which must be either a constant or a
6486 global value address) contains the meta-data to be associated with the
6487 root.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6488
6489<h5>Semantics:</h5>
Chris Lattner05d67092008-04-24 05:59:56 +0000[diff] [blame]6490<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6491 location. At compile-time, the code generator generates information to allow
6492 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
6493 intrinsic may only be used in a function which <a href="#gc">specifies a GC
6494 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6495
6496</div>
6497
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6498<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6499<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6500 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6501</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6502
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6503<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6504
6505<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6506<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6507 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6508</pre>
6509
6510<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6511<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6512 locations, allowing garbage collector implementations that require read
6513 barriers.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6514
6515<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6516<p>The second argument is the address to read from, which should be an address
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6517 allocated from the garbage collector. The first object is a pointer to the
6518 start of the referenced object, if needed by the language runtime (otherwise
6519 null).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6520
6521<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6522<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6523 instruction, but may be replaced with substantially more complex code by the
6524 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
6525 may only be used in a function which <a href="#gc">specifies a GC
6526 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6527
6528</div>
6529
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6530<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6531<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6532 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6533</h4>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6534
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6535<div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6536
6537<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6538<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6539 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6540</pre>
6541
6542<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6543<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6544 locations, allowing garbage collector implementations that require write
6545 barriers (such as generational or reference counting collectors).</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6546
6547<h5>Arguments:</h5>
Chris Lattner80626e92006-03-14 20:02:51 +0000[diff] [blame]6548<p>The first argument is the reference to store, the second is the start of the
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6549 object to store it to, and the third is the address of the field of Obj to
6550 store to. If the runtime does not require a pointer to the object, Obj may
6551 be null.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6552
6553<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6554<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6555 instruction, but may be replaced with substantially more complex code by the
6556 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
6557 may only be used in a function which <a href="#gc">specifies a GC
6558 algorithm</a>.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6559
6560</div>
6561
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6562</div>
6563
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]6564<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6565<h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6566 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6567</h3>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6568
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6569<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6570
6571<p>These intrinsics are provided by LLVM to expose special features that may
6572 only be implemented with code generator support.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6573
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6574<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6575<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6576 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6577</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6578
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6579<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6580
6581<h5>Syntax:</h5>
6582<pre>
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]6583 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6584</pre>
6585
6586<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6587<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
6588 target-specific value indicating the return address of the current function
6589 or one of its callers.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6590
6591<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6592<p>The argument to this intrinsic indicates which function to return the address
6593 for. Zero indicates the calling function, one indicates its caller, etc.
6594 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6595
6596<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6597<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
6598 indicating the return address of the specified call frame, or zero if it
6599 cannot be identified. The value returned by this intrinsic is likely to be
6600 incorrect or 0 for arguments other than zero, so it should only be used for
6601 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6602
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6603<p>Note that calling this intrinsic does not prevent function inlining or other
6604 aggressive transformations, so the value returned may not be that of the
6605 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6606
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6607</div>
6608
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6609<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6610<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6611 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6612</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6613
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6614<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6615
6616<h5>Syntax:</h5>
6617<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6618 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6619</pre>
6620
6621<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6622<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
6623 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6624
6625<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6626<p>The argument to this intrinsic indicates which function to return the frame
6627 pointer for. Zero indicates the calling function, one indicates its caller,
6628 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6629
6630<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6631<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
6632 indicating the frame address of the specified call frame, or zero if it
6633 cannot be identified. The value returned by this intrinsic is likely to be
6634 incorrect or 0 for arguments other than zero, so it should only be used for
6635 debugging purposes.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6636
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6637<p>Note that calling this intrinsic does not prevent function inlining or other
6638 aggressive transformations, so the value returned may not be that of the
6639 obvious source-language caller.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6640
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6641</div>
6642
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6643<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6644<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6645 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6646</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6647
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6648<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6649
6650<h5>Syntax:</h5>
6651<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6652 declare i8* @llvm.stacksave()
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6653</pre>
6654
6655<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6656<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
6657 of the function stack, for use
6658 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
6659 useful for implementing language features like scoped automatic variable
6660 sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6661
6662<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6663<p>This intrinsic returns a opaque pointer value that can be passed
6664 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
6665 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
6666 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
6667 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
6668 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
6669 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6670
6671</div>
6672
6673<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6674<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6675 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6676</h4>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6677
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6678<div>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6679
6680<h5>Syntax:</h5>
6681<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6682 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6683</pre>
6684
6685<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6686<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
6687 the function stack to the state it was in when the
6688 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
6689 executed. This is useful for implementing language features like scoped
6690 automatic variable sized arrays in C99.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6691
6692<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6693<p>See the description
6694 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6695
6696</div>
6697
Chris Lattner57e1f392006-01-13 02:03:13 +0000[diff] [blame]6698<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6699<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6700 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6701</h4>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6702
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6703<div>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6704
6705<h5>Syntax:</h5>
6706<pre>
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6707 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;, i32 &lt;cache type&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6708</pre>
6709
6710<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6711<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
6712 insert a prefetch instruction if supported; otherwise, it is a noop.
6713 Prefetches have no effect on the behavior of the program but can change its
6714 performance characteristics.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6715
6716<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6717<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
6718 specifier determining if the fetch should be for a read (0) or write (1),
6719 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Bruno Cardoso Lopes9a767332011-06-14 04:58:37 +0000[diff] [blame]6720 locality, to (3) - extremely local keep in cache. The <tt>cache type</tt>
6721 specifies whether the prefetch is performed on the data (1) or instruction (0)
6722 cache. The <tt>rw</tt>, <tt>locality</tt> and <tt>cache type</tt> arguments
6723 must be constant integers.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6724
6725<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6726<p>This intrinsic does not modify the behavior of the program. In particular,
6727 prefetches cannot trap and do not produce a value. On targets that support
6728 this intrinsic, the prefetch can provide hints to the processor cache for
6729 better performance.</p>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]6730
6731</div>
6732
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6733<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6734<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6735 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6736</h4>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6737
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6738<div>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6739
6740<h5>Syntax:</h5>
6741<pre>
Chris Lattner1df4f752007-09-21 17:30:40 +0000[diff] [blame]6742 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6743</pre>
6744
6745<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6746<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
6747 Counter (PC) in a region of code to simulators and other tools. The method
6748 is target specific, but it is expected that the marker will use exported
6749 symbols to transmit the PC of the marker. The marker makes no guarantees
6750 that it will remain with any specific instruction after optimizations. It is
6751 possible that the presence of a marker will inhibit optimizations. The
6752 intended use is to be inserted after optimizations to allow correlations of
6753 simulation runs.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6754
6755<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6756<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6757
6758<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6759<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6760 not support this intrinsic may ignore it.</p>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]6761
6762</div>
6763
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6764<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6765<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6766 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6767</h4>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6768
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6769<div>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6770
6771<h5>Syntax:</h5>
6772<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]6773 declare i64 @llvm.readcyclecounter()
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6774</pre>
6775
6776<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6777<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6778 counter register (or similar low latency, high accuracy clocks) on those
6779 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6780 should map to RPCC. As the backing counters overflow quickly (on the order
6781 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6782
6783<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6784<p>When directly supported, reading the cycle counter should not modify any
6785 memory. Implementations are allowed to either return a application specific
6786 value or a system wide value. On backends without support, this is lowered
6787 to a constant 0.</p>
Andrew Lenharth51b8d542005-11-11 16:47:30 +0000[diff] [blame]6788
6789</div>
6790
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6791</div>
6792
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6793<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6794<h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6795 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6796</h3>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6797
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6798<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6799
6800<p>LLVM provides intrinsics for a few important standard C library functions.
6801 These intrinsics allow source-language front-ends to pass information about
6802 the alignment of the pointer arguments to the code generator, providing
6803 opportunity for more efficient code generation.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6804
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6805<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6806<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6807 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6808</h4>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6809
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6810<div>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6811
6812<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6813<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
Mon P Wange88909b2010-04-07 06:35:53 +0000[diff] [blame]6814 integer bit width and for different address spaces. Not all targets support
6815 all bit widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6816
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6817<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6818 declare void @llvm.memcpy.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6819 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6820 declare void @llvm.memcpy.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6821 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6822</pre>
6823
6824<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6825<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6826 source location to the destination location.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6827
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6828<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6829 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6830 and the pointers can be in specified address spaces.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6831
6832<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6833
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6834<p>The first argument is a pointer to the destination, the second is a pointer
6835 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6836 number of bytes to copy, the fourth argument is the alignment of the
6837 source and destination locations, and the fifth is a boolean indicating a
6838 volatile access.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6839
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6840<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6841 then the caller guarantees that both the source and destination pointers are
6842 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6843
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6844<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6845 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6846 The detailed access behavior is not very cleanly specified and it is unwise
6847 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6848
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6849<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6850
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6851<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6852 source location to the destination location, which are not allowed to
6853 overlap. It copies "len" bytes of memory over. If the argument is known to
6854 be aligned to some boundary, this can be specified as the fourth argument,
6855 otherwise it should be set to 0 or 1.</p>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6856
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]6857</div>
6858
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6859<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6860<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6861 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6862</h4>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6863
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6864<div>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6865
6866<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6867<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Mon P Wange88909b2010-04-07 06:35:53 +0000[diff] [blame]6868 width and for different address space. Not all targets support all bit
6869 widths however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6870
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6871<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6872 declare void @llvm.memmove.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6873 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6874 declare void @llvm.memmove.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6875 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6876</pre>
6877
6878<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6879<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6880 source location to the destination location. It is similar to the
6881 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6882 overlap.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6883
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6884<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6885 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6886 and the pointers can be in specified address spaces.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6887
6888<h5>Arguments:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6889
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6890<p>The first argument is a pointer to the destination, the second is a pointer
6891 to the source. The third argument is an integer argument specifying the
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6892 number of bytes to copy, the fourth argument is the alignment of the
6893 source and destination locations, and the fifth is a boolean indicating a
6894 volatile access.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6895
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6896<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6897 then the caller guarantees that the source and destination pointers are
6898 aligned to that boundary.</p>
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]6899
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6900<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6901 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6902 The detailed access behavior is not very cleanly specified and it is unwise
6903 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6904
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6905<h5>Semantics:</h5>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6906
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6907<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6908 source location to the destination location, which may overlap. It copies
6909 "len" bytes of memory over. If the argument is known to be aligned to some
6910 boundary, this can be specified as the fourth argument, otherwise it should
6911 be set to 0 or 1.</p>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6912
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]6913</div>
6914
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6915<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6916<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6917 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6918</h4>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6919
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6920<div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6921
6922<h5>Syntax:</h5>
Chris Lattner824b9582008-11-21 16:42:48 +0000[diff] [blame]6923<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6924 width and for different address spaces. However, not all targets support all
6925 bit widths.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6926
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6927<pre>
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6928 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6929 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]6930 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerff35c3f2010-04-08 00:54:34 +0000[diff] [blame]6931 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6932</pre>
6933
6934<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6935<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6936 particular byte value.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6937
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6938<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6939 intrinsic does not return a value and takes extra alignment/volatile
6940 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6941
6942<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6943<p>The first argument is a pointer to the destination to fill, the second is the
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6944 byte value with which to fill it, the third argument is an integer argument
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6945 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellcdcbbfc2010-07-30 16:30:28 +0000[diff] [blame]6946 alignment of the destination location.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6947
Dan Gohmanb55a1ee2010-03-01 17:41:39 +0000[diff] [blame]6948<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6949 then the caller guarantees that the destination pointer is aligned to that
6950 boundary.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6951
Jeffrey Yasskin93e066d2010-04-26 21:21:24 +0000[diff] [blame]6952<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6953 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6954 The detailed access behavior is not very cleanly specified and it is unwise
6955 to depend on it.</p>
Chris Lattner9f636de2010-04-08 00:53:57 +0000[diff] [blame]6956
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6957<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6958<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6959 at the destination location. If the argument is known to be aligned to some
6960 boundary, this can be specified as the fourth argument, otherwise it should
6961 be set to 0 or 1.</p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6962
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]6963</div>
6964
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]6965<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6966<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]6967 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]6968</h4>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6969
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]6970<div>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6971
6972<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6973<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6974 floating point or vector of floating point type. Not all targets support all
6975 types however.</p>
6976
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6977<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]6978 declare float @llvm.sqrt.f32(float %Val)
6979 declare double @llvm.sqrt.f64(double %Val)
6980 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6981 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6982 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6983</pre>
6984
6985<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6986<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6987 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6988 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6989 behavior for negative numbers other than -0.0 (which allows for better
6990 optimization, because there is no need to worry about errno being
6991 set). <tt>llvm.sqrt(-0.0)</tt> is defined to return -0.0 like IEEE sqrt.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6992
6993<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6994<p>The argument and return value are floating point numbers of the same
6995 type.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]6996
6997<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]6998<p>This function returns the sqrt of the specified operand if it is a
6999 nonnegative floating point number.</p>
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7000
Chris Lattnera4d74142005-07-21 01:29:16 +0000[diff] [blame]7001</div>
7002
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7003<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7004<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7005 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7006</h4>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7007
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7008<div>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7009
7010<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7011<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
7012 floating point or vector of floating point type. Not all targets support all
7013 types however.</p>
7014
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7015<pre>
Dale Johannesen408f9c12007-10-02 17:47:38 +0000[diff] [blame]7016 declare float @llvm.powi.f32(float %Val, i32 %power)
7017 declare double @llvm.powi.f64(double %Val, i32 %power)
7018 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
7019 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
7020 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7021</pre>
7022
7023<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7024<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
7025 specified (positive or negative) power. The order of evaluation of
7026 multiplications is not defined. When a vector of floating point type is
7027 used, the second argument remains a scalar integer value.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7028
7029<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7030<p>The second argument is an integer power, and the first is a value to raise to
7031 that power.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7032
7033<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7034<p>This function returns the first value raised to the second power with an
7035 unspecified sequence of rounding operations.</p>
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7036
Chris Lattnerf4d252d2006-09-08 06:34:02 +0000[diff] [blame]7037</div>
7038
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7039<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7040<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7041 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7042</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7043
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7044<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7045
7046<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7047<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
7048 floating point or vector of floating point type. Not all targets support all
7049 types however.</p>
7050
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7051<pre>
7052 declare float @llvm.sin.f32(float %Val)
7053 declare double @llvm.sin.f64(double %Val)
7054 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
7055 declare fp128 @llvm.sin.f128(fp128 %Val)
7056 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
7057</pre>
7058
7059<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7060<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7061
7062<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7063<p>The argument and return value are floating point numbers of the same
7064 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7065
7066<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7067<p>This function returns the sine of the specified operand, returning the same
7068 values as the libm <tt>sin</tt> functions would, and handles error conditions
7069 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7070
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7071</div>
7072
7073<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7074<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7075 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7076</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7077
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7078<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7079
7080<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7081<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
7082 floating point or vector of floating point type. Not all targets support all
7083 types however.</p>
7084
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7085<pre>
7086 declare float @llvm.cos.f32(float %Val)
7087 declare double @llvm.cos.f64(double %Val)
7088 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
7089 declare fp128 @llvm.cos.f128(fp128 %Val)
7090 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
7091</pre>
7092
7093<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7094<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7095
7096<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7097<p>The argument and return value are floating point numbers of the same
7098 type.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7099
7100<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7101<p>This function returns the cosine of the specified operand, returning the same
7102 values as the libm <tt>cos</tt> functions would, and handles error conditions
7103 in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7104
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7105</div>
7106
7107<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7108<h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7109 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7110</h4>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7111
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7112<div>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7113
7114<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7115<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
7116 floating point or vector of floating point type. Not all targets support all
7117 types however.</p>
7118
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7119<pre>
7120 declare float @llvm.pow.f32(float %Val, float %Power)
7121 declare double @llvm.pow.f64(double %Val, double %Power)
7122 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
7123 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
7124 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
7125</pre>
7126
7127<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7128<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
7129 specified (positive or negative) power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7130
7131<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7132<p>The second argument is a floating point power, and the first is a value to
7133 raise to that power.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7134
7135<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7136<p>This function returns the first value raised to the second power, returning
7137 the same values as the libm <tt>pow</tt> functions would, and handles error
7138 conditions in the same way.</p>
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7139
Dan Gohman91c284c2007-10-15 20:30:11 +0000[diff] [blame]7140</div>
7141
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7142<!-- _______________________________________________________________________ -->
7143<h4>
7144 <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
7145</h4>
7146
7147<div>
7148
7149<h5>Syntax:</h5>
7150<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
7151 floating point or vector of floating point type. Not all targets support all
7152 types however.</p>
7153
7154<pre>
7155 declare float @llvm.exp.f32(float %Val)
7156 declare double @llvm.exp.f64(double %Val)
7157 declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
7158 declare fp128 @llvm.exp.f128(fp128 %Val)
7159 declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
7160</pre>
7161
7162<h5>Overview:</h5>
7163<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
7164
7165<h5>Arguments:</h5>
7166<p>The argument and return value are floating point numbers of the same
7167 type.</p>
7168
7169<h5>Semantics:</h5>
7170<p>This function returns the same values as the libm <tt>exp</tt> functions
7171 would, and handles error conditions in the same way.</p>
7172
7173</div>
7174
7175<!-- _______________________________________________________________________ -->
7176<h4>
7177 <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
7178</h4>
7179
7180<div>
7181
7182<h5>Syntax:</h5>
7183<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
7184 floating point or vector of floating point type. Not all targets support all
7185 types however.</p>
7186
7187<pre>
7188 declare float @llvm.log.f32(float %Val)
7189 declare double @llvm.log.f64(double %Val)
7190 declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
7191 declare fp128 @llvm.log.f128(fp128 %Val)
7192 declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
7193</pre>
7194
7195<h5>Overview:</h5>
7196<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
7197
7198<h5>Arguments:</h5>
7199<p>The argument and return value are floating point numbers of the same
7200 type.</p>
7201
7202<h5>Semantics:</h5>
7203<p>This function returns the same values as the libm <tt>log</tt> functions
7204 would, and handles error conditions in the same way.</p>
7205
Nick Lewycky1c929be2011-10-31 01:32:21 +0000[diff] [blame]7206</div>
7207
7208<!-- _______________________________________________________________________ -->
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7209<h4>
7210 <a name="int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a>
7211</h4>
7212
7213<div>
7214
7215<h5>Syntax:</h5>
7216<p>This is an overloaded intrinsic. You can use <tt>llvm.fma</tt> on any
7217 floating point or vector of floating point type. Not all targets support all
7218 types however.</p>
7219
7220<pre>
7221 declare float @llvm.fma.f32(float %a, float %b, float %c)
7222 declare double @llvm.fma.f64(double %a, double %b, double %c)
7223 declare x86_fp80 @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
7224 declare fp128 @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
7225 declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)
7226</pre>
7227
7228<h5>Overview:</h5>
Cameron Zwarichabc43e62011-07-08 22:13:55 +0000[diff] [blame]7229<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarich33390842011-07-08 21:39:21 +0000[diff] [blame]7230 operation.</p>
7231
7232<h5>Arguments:</h5>
7233<p>The argument and return value are floating point numbers of the same
7234 type.</p>
7235
7236<h5>Semantics:</h5>
7237<p>This function returns the same values as the libm <tt>fma</tt> functions
7238 would.</p>
7239
Dan Gohman4e9011c2011-05-23 21:13:03 +0000[diff] [blame]7240</div>
7241
NAKAMURA Takumi4b2e07a2011-10-31 13:04:26 +0000[diff] [blame]7242</div>
7243
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7244<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7245<h3>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7246 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7247</h3>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7248
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7249<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7250
7251<p>LLVM provides intrinsics for a few important bit manipulation operations.
7252 These allow efficient code generation for some algorithms.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7253
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7254<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7255<h4>
Reid Spencera3e435f2007-04-04 02:42:35 +0000[diff] [blame]7256 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7257</h4>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7258
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7259<div>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7260
7261<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7262<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7263 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7264
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7265<pre>
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7266 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
7267 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
7268 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7269</pre>
7270
7271<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7272<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
7273 values with an even number of bytes (positive multiple of 16 bits). These
7274 are useful for performing operations on data that is not in the target's
7275 native byte order.</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7276
7277<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7278<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
7279 and low byte of the input i16 swapped. Similarly,
7280 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
7281 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
7282 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
7283 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
7284 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
7285 more, respectively).</p>
Nate Begeman7e36c472006-01-13 23:26:38 +0000[diff] [blame]7286
7287</div>
7288
7289<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7290<h4>
Reid Spencer0b118202006-01-16 21:12:35 +0000[diff] [blame]7291 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7292</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7293
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7294<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7295
7296<h5>Syntax:</h5>
Reid Spencer409e28f2007-04-01 08:04:23 +0000[diff] [blame]7297<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7298 width, or on any vector with integer elements. Not all targets support all
7299 bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7300
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7301<pre>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7302 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7303 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovec43a062007-03-22 00:02:17 +0000[diff] [blame]7304 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth69940402007-08-04 01:51:18 +0000[diff] [blame]7305 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
7306 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7307 declare &lt;2 x i32&gt; @llvm.ctpop.v2i32(&lt;2 x i32&gt; &lt;src&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7308</pre>
7309
7310<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7311<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
7312 in a value.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7313
7314<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7315<p>The only argument is the value to be counted. The argument may be of any
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7316 integer type, or a vector with integer elements.
7317 The return type must match the argument type.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7318
7319<h5>Semantics:</h5>
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7320<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable, or within each
7321 element of a vector.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7322
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7323</div>
7324
7325<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7326<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7327 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7328</h4>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7329
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7330<div>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7331
7332<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7333<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7334 integer bit width, or any vector whose elements are integers. Not all
7335 targets support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7336
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7337<pre>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7338 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7339 declare i16 @llvm.ctlz.i16 (i16 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7340 declare i32 @llvm.ctlz.i32 (i32 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7341 declare i64 @llvm.ctlz.i64 (i64 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7342 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7343 declase &lt;2 x i32&gt; @llvm.ctlz.v2i32(&lt;2 x i32&gt; &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7344</pre>
7345
7346<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7347<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
7348 leading zeros in a variable.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7349
7350<h5>Arguments:</h5>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7351<p>The first argument is the value to be counted. This argument may be of any
7352 integer type, or a vectory with integer element type. The return type
7353 must match the first argument type.</p>
7354
7355<p>The second argument must be a constant and is a flag to indicate whether the
7356 intrinsic should ensure that a zero as the first argument produces a defined
7357 result. Historically some architectures did not provide a defined result for
7358 zero values as efficiently, and many algorithms are now predicated on
7359 avoiding zero-value inputs.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7360
7361<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7362<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7363 zeros in a variable, or within each element of the vector.
7364 If <tt>src == 0</tt> then the result is the size in bits of the type of
7365 <tt>src</tt> if <tt>is_zero_undef == 0</tt> and <tt>undef</tt> otherwise.
7366 For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7367
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]7368</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]7369
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7370<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7371<h4>
Chris Lattner8a886be2006-01-16 22:34:14 +0000[diff] [blame]7372 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7373</h4>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7374
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7375<div>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7376
7377<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7378<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7379 integer bit width, or any vector of integer elements. Not all targets
7380 support all bit widths or vector types, however.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7381
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7382<pre>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7383 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7384 declare i16 @llvm.cttz.i16 (i16 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7385 declare i32 @llvm.cttz.i32 (i32 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7386 declare i64 @llvm.cttz.i64 (i64 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7387 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7388 declase &lt;2 x i32&gt; @llvm.cttz.v2i32(&lt;2 x i32&gt; &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7389</pre>
7390
7391<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7392<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
7393 trailing zeros.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7394
7395<h5>Arguments:</h5>
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7396<p>The first argument is the value to be counted. This argument may be of any
7397 integer type, or a vectory with integer element type. The return type
7398 must match the first argument type.</p>
7399
7400<p>The second argument must be a constant and is a flag to indicate whether the
7401 intrinsic should ensure that a zero as the first argument produces a defined
7402 result. Historically some architectures did not provide a defined result for
7403 zero values as efficiently, and many algorithms are now predicated on
7404 avoiding zero-value inputs.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7405
7406<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7407<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Andersonf1ac4652011-07-01 21:52:38 +0000[diff] [blame]7408 zeros in a variable, or within each element of a vector.
Chandler Carruth48b0bbf2011-12-12 04:36:04 +0000[diff] [blame]7409 If <tt>src == 0</tt> then the result is the size in bits of the type of
7410 <tt>src</tt> if <tt>is_zero_undef == 0</tt> and <tt>undef</tt> otherwise.
7411 For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7412
Chris Lattnereff29ab2005-05-15 19:39:26 +0000[diff] [blame]7413</div>
7414
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7415</div>
7416
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7417<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7418<h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7419 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7420</h3>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7421
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7422<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7423
7424<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingda01af72009-02-08 04:04:40 +0000[diff] [blame]7425
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7426<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7427<h4>
7428 <a name="int_sadd_overflow">
7429 '<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics
7430 </a>
7431</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7432
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7433<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7434
7435<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7436<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7437 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7438
7439<pre>
7440 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
7441 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7442 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
7443</pre>
7444
7445<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7446<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7447 a signed addition of the two arguments, and indicate whether an overflow
7448 occurred during the signed summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7449
7450<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7451<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7452 be of integer types of any bit width, but they must have the same bit
7453 width. The second element of the result structure must be of
7454 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7455 undergo signed addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7456
7457<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7458<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7459 a signed addition of the two variables. They return a structure &mdash; the
7460 first element of which is the signed summation, and the second element of
7461 which is a bit specifying if the signed summation resulted in an
7462 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7463
7464<h5>Examples:</h5>
7465<pre>
7466 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7467 %sum = extractvalue {i32, i1} %res, 0
7468 %obit = extractvalue {i32, i1} %res, 1
7469 br i1 %obit, label %overflow, label %normal
7470</pre>
7471
7472</div>
7473
7474<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7475<h4>
7476 <a name="int_uadd_overflow">
7477 '<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics
7478 </a>
7479</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7480
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7481<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7482
7483<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7484<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7485 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7486
7487<pre>
7488 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
7489 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7490 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
7491</pre>
7492
7493<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7494<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7495 an unsigned addition of the two arguments, and indicate whether a carry
7496 occurred during the unsigned summation.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7497
7498<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7499<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7500 be of integer types of any bit width, but they must have the same bit
7501 width. The second element of the result structure must be of
7502 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7503 undergo unsigned addition.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7504
7505<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7506<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7507 an unsigned addition of the two arguments. They return a structure &mdash;
7508 the first element of which is the sum, and the second element of which is a
7509 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7510
7511<h5>Examples:</h5>
7512<pre>
7513 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7514 %sum = extractvalue {i32, i1} %res, 0
7515 %obit = extractvalue {i32, i1} %res, 1
7516 br i1 %obit, label %carry, label %normal
7517</pre>
7518
7519</div>
7520
7521<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7522<h4>
7523 <a name="int_ssub_overflow">
7524 '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
7525 </a>
7526</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7527
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7528<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7529
7530<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7531<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7532 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7533
7534<pre>
7535 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
7536 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7537 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
7538</pre>
7539
7540<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7541<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7542 a signed subtraction of the two arguments, and indicate whether an overflow
7543 occurred during the signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7544
7545<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7546<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7547 be of integer types of any bit width, but they must have the same bit
7548 width. The second element of the result structure must be of
7549 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7550 undergo signed subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7551
7552<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7553<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7554 a signed subtraction of the two arguments. They return a structure &mdash;
7555 the first element of which is the subtraction, and the second element of
7556 which is a bit specifying if the signed subtraction resulted in an
7557 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7558
7559<h5>Examples:</h5>
7560<pre>
7561 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7562 %sum = extractvalue {i32, i1} %res, 0
7563 %obit = extractvalue {i32, i1} %res, 1
7564 br i1 %obit, label %overflow, label %normal
7565</pre>
7566
7567</div>
7568
7569<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7570<h4>
7571 <a name="int_usub_overflow">
7572 '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
7573 </a>
7574</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7575
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7576<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7577
7578<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7579<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7580 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7581
7582<pre>
7583 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
7584 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7585 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
7586</pre>
7587
7588<h5>Overview:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7589<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7590 an unsigned subtraction of the two arguments, and indicate whether an
7591 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7592
7593<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7594<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7595 be of integer types of any bit width, but they must have the same bit
7596 width. The second element of the result structure must be of
7597 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7598 undergo unsigned subtraction.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7599
7600<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7601<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7602 an unsigned subtraction of the two arguments. They return a structure &mdash;
7603 the first element of which is the subtraction, and the second element of
7604 which is a bit specifying if the unsigned subtraction resulted in an
7605 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7606
7607<h5>Examples:</h5>
7608<pre>
7609 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7610 %sum = extractvalue {i32, i1} %res, 0
7611 %obit = extractvalue {i32, i1} %res, 1
7612 br i1 %obit, label %overflow, label %normal
7613</pre>
7614
7615</div>
7616
7617<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7618<h4>
7619 <a name="int_smul_overflow">
7620 '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
7621 </a>
7622</h4>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7623
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7624<div>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7625
7626<h5>Syntax:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7627<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7628 on any integer bit width.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7629
7630<pre>
7631 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
7632 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7633 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
7634</pre>
7635
7636<h5>Overview:</h5>
7637
7638<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7639 a signed multiplication of the two arguments, and indicate whether an
7640 overflow occurred during the signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7641
7642<h5>Arguments:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7643<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7644 be of integer types of any bit width, but they must have the same bit
7645 width. The second element of the result structure must be of
7646 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7647 undergo signed multiplication.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7648
7649<h5>Semantics:</h5>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7650<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7651 a signed multiplication of the two arguments. They return a structure &mdash;
7652 the first element of which is the multiplication, and the second element of
7653 which is a bit specifying if the signed multiplication resulted in an
7654 overflow.</p>
Bill Wendlingac1df8e2009-02-08 01:40:31 +0000[diff] [blame]7655
7656<h5>Examples:</h5>
7657<pre>
7658 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7659 %sum = extractvalue {i32, i1} %res, 0
7660 %obit = extractvalue {i32, i1} %res, 1
7661 br i1 %obit, label %overflow, label %normal
7662</pre>
7663
Reid Spencerf86037f2007-04-11 23:23:49 +0000[diff] [blame]7664</div>
7665
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7666<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7667<h4>
7668 <a name="int_umul_overflow">
7669 '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
7670 </a>
7671</h4>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7672
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7673<div>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7674
7675<h5>Syntax:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7676<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7677 on any integer bit width.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7678
7679<pre>
7680 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
7681 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7682 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
7683</pre>
7684
7685<h5>Overview:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7686<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7687 a unsigned multiplication of the two arguments, and indicate whether an
7688 overflow occurred during the unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7689
7690<h5>Arguments:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7691<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7692 be of integer types of any bit width, but they must have the same bit
7693 width. The second element of the result structure must be of
7694 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7695 undergo unsigned multiplication.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7696
7697<h5>Semantics:</h5>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7698<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7699 an unsigned multiplication of the two arguments. They return a structure
7700 &mdash; the first element of which is the multiplication, and the second
7701 element of which is a bit specifying if the unsigned multiplication resulted
7702 in an overflow.</p>
Bill Wendling41b485c2009-02-08 23:00:09 +0000[diff] [blame]7703
7704<h5>Examples:</h5>
7705<pre>
7706 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7707 %sum = extractvalue {i32, i1} %res, 0
7708 %obit = extractvalue {i32, i1} %res, 1
7709 br i1 %obit, label %overflow, label %normal
7710</pre>
7711
7712</div>
7713
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7714</div>
7715
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7716<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7717<h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7718 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7719</h3>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7720
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7721<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7722
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7723<p>Half precision floating point is a storage-only format. This means that it is
7724 a dense encoding (in memory) but does not support computation in the
7725 format.</p>
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7726
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7727<p>This means that code must first load the half-precision floating point
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7728 value as an i16, then convert it to float with <a
7729 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
7730 Computation can then be performed on the float value (including extending to
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7731 double etc). To store the value back to memory, it is first converted to
7732 float if needed, then converted to i16 with
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7733 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
7734 storing as an i16 value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7735
7736<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7737<h4>
7738 <a name="int_convert_to_fp16">
7739 '<tt>llvm.convert.to.fp16</tt>' Intrinsic
7740 </a>
7741</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7742
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7743<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7744
7745<h5>Syntax:</h5>
7746<pre>
7747 declare i16 @llvm.convert.to.fp16(f32 %a)
7748</pre>
7749
7750<h5>Overview:</h5>
7751<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7752 a conversion from single precision floating point format to half precision
7753 floating point format.</p>
7754
7755<h5>Arguments:</h5>
7756<p>The intrinsic function contains single argument - the value to be
7757 converted.</p>
7758
7759<h5>Semantics:</h5>
7760<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7761 a conversion from single precision floating point format to half precision
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7762 floating point format. The return value is an <tt>i16</tt> which
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7763 contains the converted number.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7764
7765<h5>Examples:</h5>
7766<pre>
7767 %res = call i16 @llvm.convert.to.fp16(f32 %a)
7768 store i16 %res, i16* @x, align 2
7769</pre>
7770
7771</div>
7772
7773<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7774<h4>
7775 <a name="int_convert_from_fp16">
7776 '<tt>llvm.convert.from.fp16</tt>' Intrinsic
7777 </a>
7778</h4>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7779
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7780<div>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7781
7782<h5>Syntax:</h5>
7783<pre>
7784 declare f32 @llvm.convert.from.fp16(i16 %a)
7785</pre>
7786
7787<h5>Overview:</h5>
7788<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
7789 a conversion from half precision floating point format to single precision
7790 floating point format.</p>
7791
7792<h5>Arguments:</h5>
7793<p>The intrinsic function contains single argument - the value to be
7794 converted.</p>
7795
7796<h5>Semantics:</h5>
7797<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner0cec9c82010-03-15 04:12:21 +0000[diff] [blame]7798 conversion from half single precision floating point format to single
Chris Lattner82c3dc62010-03-14 23:03:31 +0000[diff] [blame]7799 precision floating point format. The input half-float value is represented by
7800 an <tt>i16</tt> value.</p>
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7801
7802<h5>Examples:</h5>
7803<pre>
7804 %a = load i16* @x, align 2
7805 %res = call f32 @llvm.convert.from.fp16(i16 %a)
7806</pre>
7807
7808</div>
7809
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7810</div>
7811
Anton Korobeynikovf02e7302010-03-14 18:42:47 +0000[diff] [blame]7812<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7813<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7814 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7815</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7816
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7817<div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7818
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7819<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
7820 prefix), are described in
7821 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
7822 Level Debugging</a> document.</p>
7823
7824</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]7825
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7826<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7827<h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7828 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7829</h3>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7830
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7831<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7832
7833<p>The LLVM exception handling intrinsics (which all start with
7834 <tt>llvm.eh.</tt> prefix), are described in
7835 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
7836 Handling</a> document.</p>
7837
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]7838</div>
7839
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]7840<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7841<h3>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7842 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7843</h3>
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7844
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7845<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7846
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7847<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohmanff235352010-07-02 23:18:08 +0000[diff] [blame]7848 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
7849 The result is a callable
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7850 function pointer lacking the nest parameter - the caller does not need to
7851 provide a value for it. Instead, the value to use is stored in advance in a
7852 "trampoline", a block of memory usually allocated on the stack, which also
7853 contains code to splice the nest value into the argument list. This is used
7854 to implement the GCC nested function address extension.</p>
7855
7856<p>For example, if the function is
7857 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
7858 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
7859 follows:</p>
7860
Benjamin Kramer26fe25f2010-07-13 12:26:09 +0000[diff] [blame]7861<pre class="doc_code">
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]7862 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
7863 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7864 call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8*, i32, i32)* @f to i8*), i8* %nval)
7865 %p = call i8* @llvm.adjust.trampoline(i8* %tramp1)
Duncan Sandsf7331b32007-09-11 14:10:23 +0000[diff] [blame]7866 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7867</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7868
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]7869<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
7870 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7871
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7872<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7873<h4>
7874 <a name="int_it">
7875 '<tt>llvm.init.trampoline</tt>' Intrinsic
7876 </a>
7877</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7878
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7879<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7880
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7881<h5>Syntax:</h5>
7882<pre>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7883 declare void @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7884</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7885
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7886<h5>Overview:</h5>
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7887<p>This fills the memory pointed to by <tt>tramp</tt> with executable code,
7888 turning it into a trampoline.</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7889
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7890<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7891<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
7892 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
7893 sufficiently aligned block of memory; this memory is written to by the
7894 intrinsic. Note that the size and the alignment are target-specific - LLVM
7895 currently provides no portable way of determining them, so a front-end that
7896 generates this intrinsic needs to have some target-specific knowledge.
7897 The <tt>func</tt> argument must hold a function bitcast to
7898 an <tt>i8*</tt>.</p>
7899
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7900<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7901<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands4a544a72011-09-06 13:37:06 +0000[diff] [blame]7902 dependent code, turning it into a function. Then <tt>tramp</tt> needs to be
7903 passed to <a href="#int_at">llvm.adjust.trampoline</a> to get a pointer
7904 which can be <a href="#int_trampoline">bitcast (to a new function) and
7905 called</a>. The new function's signature is the same as that of
7906 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
7907 removed. At most one such <tt>nest</tt> argument is allowed, and it must be of
7908 pointer type. Calling the new function is equivalent to calling <tt>func</tt>
7909 with the same argument list, but with <tt>nval</tt> used for the missing
7910 <tt>nest</tt> argument. If, after calling <tt>llvm.init.trampoline</tt>, the
7911 memory pointed to by <tt>tramp</tt> is modified, then the effect of any later call
7912 to the returned function pointer is undefined.</p>
7913</div>
7914
7915<!-- _______________________________________________________________________ -->
7916<h4>
7917 <a name="int_at">
7918 '<tt>llvm.adjust.trampoline</tt>' Intrinsic
7919 </a>
7920</h4>
7921
7922<div>
7923
7924<h5>Syntax:</h5>
7925<pre>
7926 declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
7927</pre>
7928
7929<h5>Overview:</h5>
7930<p>This performs any required machine-specific adjustment to the address of a
7931 trampoline (passed as <tt>tramp</tt>).</p>
7932
7933<h5>Arguments:</h5>
7934<p><tt>tramp</tt> must point to a block of memory which already has trampoline code
7935 filled in by a previous call to <a href="#int_it"><tt>llvm.init.trampoline</tt>
7936 </a>.</p>
7937
7938<h5>Semantics:</h5>
7939<p>On some architectures the address of the code to be executed needs to be
7940 different to the address where the trampoline is actually stored. This
7941 intrinsic returns the executable address corresponding to <tt>tramp</tt>
7942 after performing the required machine specific adjustments.
7943 The pointer returned can then be <a href="#int_trampoline"> bitcast and
7944 executed</a>.
7945</p>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]7946
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7947</div>
7948
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7949</div>
7950
Duncan Sands36397f52007-07-27 12:58:54 +0000[diff] [blame]7951<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7952<h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7953 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7954</h3>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7955
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7956<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7957
7958<p>This class of intrinsics exists to information about the lifetime of memory
7959 objects and ranges where variables are immutable.</p>
7960
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7961<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7962<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7963 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7964</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7965
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7966<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7967
7968<h5>Syntax:</h5>
7969<pre>
7970 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7971</pre>
7972
7973<h5>Overview:</h5>
7974<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7975 object's lifetime.</p>
7976
7977<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]7978<p>The first argument is a constant integer representing the size of the
7979 object, or -1 if it is variable sized. The second argument is a pointer to
7980 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7981
7982<h5>Semantics:</h5>
7983<p>This intrinsic indicates that before this point in the code, the value of the
7984 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
Nick Lewycky8d336592009-10-27 16:56:58 +0000[diff] [blame]7985 never be used and has an undefined value. A load from the pointer that
7986 precedes this intrinsic can be replaced with
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7987 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7988
7989</div>
7990
7991<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7992<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7993 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]7994</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7995
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]7996<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]7997
7998<h5>Syntax:</h5>
7999<pre>
8000 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8001</pre>
8002
8003<h5>Overview:</h5>
8004<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
8005 object's lifetime.</p>
8006
8007<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8008<p>The first argument is a constant integer representing the size of the
8009 object, or -1 if it is variable sized. The second argument is a pointer to
8010 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8011
8012<h5>Semantics:</h5>
8013<p>This intrinsic indicates that after this point in the code, the value of the
8014 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
8015 never be used and has an undefined value. Any stores into the memory object
8016 following this intrinsic may be removed as dead.
8017
8018</div>
8019
8020<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8021<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8022 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8023</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8024
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8025<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8026
8027<h5>Syntax:</h5>
8028<pre>
Nick Lewycky29b6cb42010-11-30 04:13:41 +0000[diff] [blame]8029 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8030</pre>
8031
8032<h5>Overview:</h5>
8033<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
8034 a memory object will not change.</p>
8035
8036<h5>Arguments:</h5>
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8037<p>The first argument is a constant integer representing the size of the
8038 object, or -1 if it is variable sized. The second argument is a pointer to
8039 the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8040
8041<h5>Semantics:</h5>
8042<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
8043 the return value, the referenced memory location is constant and
8044 unchanging.</p>
8045
8046</div>
8047
8048<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8049<h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8050 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8051</h4>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8052
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8053<div>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8054
8055<h5>Syntax:</h5>
8056<pre>
8057 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8058</pre>
8059
8060<h5>Overview:</h5>
8061<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
8062 a memory object are mutable.</p>
8063
8064<h5>Arguments:</h5>
8065<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky321333e2009-10-13 07:57:33 +0000[diff] [blame]8066 The second argument is a constant integer representing the size of the
8067 object, or -1 if it is variable sized and the third argument is a pointer
8068 to the object.</p>
Nick Lewyckycc271862009-10-13 07:03:23 +0000[diff] [blame]8069
8070<h5>Semantics:</h5>
8071<p>This intrinsic indicates that the memory is mutable again.</p>
8072
8073</div>
8074
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8075</div>
8076
Andrew Lenharth22c5c1b2008-02-16 01:24:58 +0000[diff] [blame]8077<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8078<h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8079 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8080</h3>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8081
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8082<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8083
8084<p>This class of intrinsics is designed to be generic and has no specific
8085 purpose.</p>
8086
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8087<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8088<h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8089 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8090</h4>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8091
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8092<div>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8093
8094<h5>Syntax:</h5>
8095<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8096 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8097</pre>
8098
8099<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8100<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8101
8102<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8103<p>The first argument is a pointer to a value, the second is a pointer to a
8104 global string, the third is a pointer to a global string which is the source
8105 file name, and the last argument is the line number.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8106
8107<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8108<p>This intrinsic allows annotation of local variables with arbitrary strings.
8109 This can be useful for special purpose optimizations that want to look for
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8110 these annotations. These have no other defined use; they are ignored by code
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8111 generation and optimization.</p>
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8112
Tanya Lattner6d806e92007-06-15 20:50:54 +0000[diff] [blame]8113</div>
8114
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8115<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8116<h4>
Tanya Lattnere1a8da02007-09-21 23:57:59 +0000[diff] [blame]8117 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8118</h4>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8119
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8120<div>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8121
8122<h5>Syntax:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8123<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
8124 any integer bit width.</p>
8125
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8126<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8127 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8128 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8129 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8130 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8131 declare i256 @llvm.annotation.i256(i256 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8132</pre>
8133
8134<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8135<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8136
8137<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8138<p>The first argument is an integer value (result of some expression), the
8139 second is a pointer to a global string, the third is a pointer to a global
8140 string which is the source file name, and the last argument is the line
8141 number. It returns the value of the first argument.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8142
8143<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8144<p>This intrinsic allows annotations to be put on arbitrary expressions with
8145 arbitrary strings. This can be useful for special purpose optimizations that
John Criswelle865c032011-08-19 16:57:55 +0000[diff] [blame]8146 want to look for these annotations. These have no other defined use; they
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8147 are ignored by code generation and optimization.</p>
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8148
Tanya Lattnerb6367882007-09-21 22:59:12 +0000[diff] [blame]8149</div>
Jim Laskeydd4ef1b2007-03-14 19:31:19 +0000[diff] [blame]8150
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8151<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8152<h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8153 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8154</h4>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8155
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8156<div>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8157
8158<h5>Syntax:</h5>
8159<pre>
8160 declare void @llvm.trap()
8161</pre>
8162
8163<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8164<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8165
8166<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8167<p>None.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8168
8169<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8170<p>This intrinsics is lowered to the target dependent trap instruction. If the
8171 target does not have a trap instruction, this intrinsic will be lowered to
8172 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8173
Anton Korobeynikov4cb86182008-01-15 22:31:34 +0000[diff] [blame]8174</div>
8175
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8176<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8177<h4>
Misha Brukmandccb0252008-11-22 23:55:29 +0000[diff] [blame]8178 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8179</h4>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8180
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8181<div>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8182
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8183<h5>Syntax:</h5>
8184<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8185 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8186</pre>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8187
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8188<h5>Overview:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8189<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
8190 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
8191 ensure that it is placed on the stack before local variables.</p>
8192
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8193<h5>Arguments:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8194<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
8195 arguments. The first argument is the value loaded from the stack
8196 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
8197 that has enough space to hold the value of the guard.</p>
8198
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8199<h5>Semantics:</h5>
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8200<p>This intrinsic causes the prologue/epilogue inserter to force the position of
8201 the <tt>AllocaInst</tt> stack slot to be before local variables on the
8202 stack. This is to ensure that if a local variable on the stack is
8203 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8204 the guard on the stack is checked against the original guard. If they are
Bill Wendlinge910b4c2009-07-20 02:29:24 +0000[diff] [blame]8205 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
8206 function.</p>
8207
Bill Wendling69e4adb2008-11-19 05:56:17 +0000[diff] [blame]8208</div>
8209
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8210<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8211<h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8212 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]8213</h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8214
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8215<div>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8216
8217<h5>Syntax:</h5>
8218<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]8219 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
8220 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8221</pre>
8222
8223<h5>Overview:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8224<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
8225 the optimizers to determine at compile time whether a) an operation (like
8226 memcpy) will overflow a buffer that corresponds to an object, or b) that a
8227 runtime check for overflow isn't necessary. An object in this context means
8228 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8229
8230<h5>Arguments:</h5>
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8231<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]8232 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8233 is a boolean 0 or 1. This argument determines whether you want the
8234 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
Eric Christopher8295a0a2009-12-23 00:29:49 +0000[diff] [blame]8235 1, variables are not allowed.</p>
8236
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8237<h5>Semantics:</h5>
8238<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling1b383ba2010-10-27 01:07:41 +0000[diff] [blame]8239 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
8240 depending on the <tt>type</tt> argument, if the size cannot be determined at
8241 compile time.</p>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8242
8243</div>
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8244<!-- _______________________________________________________________________ -->
8245<h4>
8246 <a name="int_expect">'<tt>llvm.expect</tt>' Intrinsic</a>
8247</h4>
Eric Christopher0e671492009-11-30 08:03:53 +0000[diff] [blame]8248
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8249<div>
8250
8251<h5>Syntax:</h5>
8252<pre>
8253 declare i32 @llvm.expect.i32(i32 &lt;val&gt;, i32 &lt;expected_val&gt;)
8254 declare i64 @llvm.expect.i64(i64 &lt;val&gt;, i64 &lt;expected_val&gt;)
8255</pre>
8256
8257<h5>Overview:</h5>
8258<p>The <tt>llvm.expect</tt> intrinsic provides information about expected (the
8259 most probable) value of <tt>val</tt>, which can be used by optimizers.</p>
8260
8261<h5>Arguments:</h5>
8262<p>The <tt>llvm.expect</tt> intrinsic takes two arguments. The first
8263 argument is a value. The second argument is an expected value, this needs to
8264 be a constant value, variables are not allowed.</p>
8265
8266<h5>Semantics:</h5>
8267<p>This intrinsic is lowered to the <tt>val</tt>.</p>
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]8268</div>
8269
8270</div>
8271
Jakub Staszakb170e2d2011-12-04 18:29:26 +0000[diff] [blame]8272</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8273<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]8274<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8275<address>
8276 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]8277 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8278 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]8279 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8280
8281 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]8282 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]8283 Last modified: $Date$
8284</address>
Chris Lattnerc7d3ab32008-01-04 04:33:49 +0000[diff] [blame]8285
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]8286</body>
8287</html>