Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 1 | <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" |
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Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3 | <html> |
| 4 | <head> |
| 5 | <title>LLVM Assembly Language Reference Manual</title> |
Reid Spencer | 3921c74 | 2004-08-26 20:44:00 +0000 | [diff] [blame] | 6 | <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> |
| 7 | <meta name="author" content="Chris Lattner"> |
| 8 | <meta name="description" |
| 9 | content="LLVM Assembly Language Reference Manual."> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 10 | <link rel="stylesheet" href="llvm.css" type="text/css"> |
| 11 | </head> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 12 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 13 | <body> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 14 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 15 | <div class="doc_title"> LLVM Language Reference Manual </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 16 | <ol> |
Misha Brukman | 9d0919f | 2003-11-08 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 Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 20 | <li><a href="#highlevel">High Level Structure</a> |
| 21 | <ol> |
| 22 | <li><a href="#modulestructure">Module Structure</a></li> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 23 | <li><a href="#linkage">Linkage Types</a></li> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 24 | <li><a href="#callingconv">Calling Conventions</a></li> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 25 | <li><a href="#globalvars">Global Variables</a></li> |
Chris Lattner | 4e9aba7 | 2006-01-23 23:23:47 +0000 | [diff] [blame] | 26 | <li><a href="#functionstructure">Functions</a></li> |
| 27 | <li><a href="#moduleasm">Module-Level Inline Assembly</a></li> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 28 | </ol> |
| 29 | </li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 30 | <li><a href="#typesystem">Type System</a> |
| 31 | <ol> |
Robert Bocchino | 7b81c75 | 2006-02-17 21:18:08 +0000 | [diff] [blame] | 32 | <li><a href="#t_primitive">Primitive Types</a> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 33 | <ol> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 34 | <li><a href="#t_classifications">Type Classifications</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 35 | </ol> |
| 36 | </li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 37 | <li><a href="#t_derived">Derived Types</a> |
| 38 | <ol> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 39 | <li><a href="#t_array">Array Type</a></li> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 40 | <li><a href="#t_function">Function Type</a></li> |
| 41 | <li><a href="#t_pointer">Pointer Type</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 42 | <li><a href="#t_struct">Structure Type</a></li> |
Andrew Lenharth | 75e1068 | 2006-12-08 17:13:00 +0000 | [diff] [blame^] | 43 | <li><a href="#t_pstruct">Packed Structure Type</a></li> |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 44 | <li><a href="#t_packed">Packed Type</a></li> |
Chris Lattner | 69c11bb | 2005-04-25 17:34:15 +0000 | [diff] [blame] | 45 | <li><a href="#t_opaque">Opaque Type</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 46 | </ol> |
| 47 | </li> |
| 48 | </ol> |
| 49 | </li> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 50 | <li><a href="#constants">Constants</a> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 51 | <ol> |
| 52 | <li><a href="#simpleconstants">Simple Constants</a> |
| 53 | <li><a href="#aggregateconstants">Aggregate Constants</a> |
| 54 | <li><a href="#globalconstants">Global Variable and Function Addresses</a> |
| 55 | <li><a href="#undefvalues">Undefined Values</a> |
| 56 | <li><a href="#constantexprs">Constant Expressions</a> |
| 57 | </ol> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 58 | </li> |
Chris Lattner | e87d653 | 2006-01-25 23:47:57 +0000 | [diff] [blame] | 59 | <li><a href="#othervalues">Other Values</a> |
| 60 | <ol> |
| 61 | <li><a href="#inlineasm">Inline Assembler Expressions</a> |
| 62 | </ol> |
| 63 | </li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 64 | <li><a href="#instref">Instruction Reference</a> |
| 65 | <ol> |
| 66 | <li><a href="#terminators">Terminator Instructions</a> |
| 67 | <ol> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 68 | <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li> |
| 69 | <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 70 | <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li> |
| 71 | <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 72 | <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li> |
Chris Lattner | 35eca58 | 2004-10-16 18:04:13 +0000 | [diff] [blame] | 73 | <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 74 | </ol> |
| 75 | </li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 76 | <li><a href="#binaryops">Binary Operations</a> |
| 77 | <ol> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 78 | <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li> |
| 79 | <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li> |
| 80 | <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li> |
Reid Spencer | 1628cec | 2006-10-26 06:15:43 +0000 | [diff] [blame] | 81 | <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li> |
| 82 | <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li> |
| 83 | <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li> |
Reid Spencer | 0a783f7 | 2006-11-02 01:53:59 +0000 | [diff] [blame] | 84 | <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li> |
| 85 | <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li> |
| 86 | <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 87 | </ol> |
| 88 | </li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 89 | <li><a href="#bitwiseops">Bitwise Binary Operations</a> |
| 90 | <ol> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 91 | <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 92 | <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 93 | <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li> |
| 94 | <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li> |
Reid Spencer | 3822ff5 | 2006-11-08 06:47:33 +0000 | [diff] [blame] | 95 | <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li> |
| 96 | <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 97 | </ol> |
| 98 | </li> |
Chris Lattner | 3df241e | 2006-04-08 23:07:04 +0000 | [diff] [blame] | 99 | <li><a href="#vectorops">Vector Operations</a> |
| 100 | <ol> |
| 101 | <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li> |
| 102 | <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li> |
| 103 | <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li> |
Chris Lattner | 3df241e | 2006-04-08 23:07:04 +0000 | [diff] [blame] | 104 | </ol> |
| 105 | </li> |
Chris Lattner | 884a970 | 2006-08-15 00:45:58 +0000 | [diff] [blame] | 106 | <li><a href="#memoryops">Memory Access and Addressing Operations</a> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 107 | <ol> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 108 | <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li> |
| 109 | <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li> |
| 110 | <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li> |
Robert Bocchino | 7b81c75 | 2006-02-17 21:18:08 +0000 | [diff] [blame] | 111 | <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li> |
| 112 | <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li> |
| 113 | <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 114 | </ol> |
| 115 | </li> |
Reid Spencer | 2fd21e6 | 2006-11-08 01:18:52 +0000 | [diff] [blame] | 116 | <li><a href="#convertops">Conversion Operations</a> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 117 | <ol> |
| 118 | <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li> |
| 119 | <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li> |
| 120 | <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li> |
| 121 | <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li> |
| 122 | <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 123 | <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li> |
| 124 | <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li> |
| 125 | <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li> |
| 126 | <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li> |
Reid Spencer | 7267925 | 2006-11-11 21:00:47 +0000 | [diff] [blame] | 127 | <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li> |
| 128 | <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li> |
Reid Spencer | 5c0ef47 | 2006-11-11 23:08:07 +0000 | [diff] [blame] | 129 | <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 130 | </ol> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 131 | <li><a href="#otherops">Other Operations</a> |
| 132 | <ol> |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 133 | <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li> |
| 134 | <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 135 | <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li> |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 136 | <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 137 | <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li> |
Chris Lattner | fb6977d | 2006-01-13 23:26:01 +0000 | [diff] [blame] | 138 | <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 139 | </ol> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 140 | </li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 141 | </ol> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 142 | </li> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 143 | <li><a href="#intrinsics">Intrinsic Functions</a> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 144 | <ol> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 145 | <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a> |
| 146 | <ol> |
| 147 | <li><a href="#i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li> |
| 148 | <li><a href="#i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li> |
| 149 | <li><a href="#i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li> |
| 150 | </ol> |
| 151 | </li> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 152 | <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a> |
| 153 | <ol> |
| 154 | <li><a href="#i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li> |
| 155 | <li><a href="#i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li> |
| 156 | <li><a href="#i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li> |
| 157 | </ol> |
| 158 | </li> |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 159 | <li><a href="#int_codegen">Code Generator Intrinsics</a> |
| 160 | <ol> |
| 161 | <li><a href="#i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li> |
| 162 | <li><a href="#i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li> |
Chris Lattner | 57e1f39 | 2006-01-13 02:03:13 +0000 | [diff] [blame] | 163 | <li><a href="#i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li> |
| 164 | <li><a href="#i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li> |
Chris Lattner | 9a9d7ac | 2005-02-28 19:24:19 +0000 | [diff] [blame] | 165 | <li><a href="#i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li> |
Andrew Lenharth | 7f4ec3b | 2005-03-28 20:05:49 +0000 | [diff] [blame] | 166 | <li><a href="#i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li> |
Andrew Lenharth | 51b8d54 | 2005-11-11 16:47:30 +0000 | [diff] [blame] | 167 | <li><a href="#i_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li> |
John Criswell | 7123e27 | 2004-04-09 16:43:20 +0000 | [diff] [blame] | 168 | </ol> |
| 169 | </li> |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 170 | <li><a href="#int_libc">Standard C Library Intrinsics</a> |
| 171 | <ol> |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 172 | <li><a href="#i_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li> |
| 173 | <li><a href="#i_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li> |
| 174 | <li><a href="#i_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li> |
Chris Lattner | ec6cb61 | 2006-01-16 22:38:59 +0000 | [diff] [blame] | 175 | <li><a href="#i_isunordered">'<tt>llvm.isunordered.*</tt>' Intrinsic</a></li> |
| 176 | <li><a href="#i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li> |
Chris Lattner | f4d252d | 2006-09-08 06:34:02 +0000 | [diff] [blame] | 177 | <li><a href="#i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li> |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 178 | </ol> |
| 179 | </li> |
Nate Begeman | 7e36c47 | 2006-01-13 23:26:38 +0000 | [diff] [blame] | 180 | <li><a href="#int_manip">Bit Manipulation Intrinsics</a> |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 181 | <ol> |
Nate Begeman | 7e36c47 | 2006-01-13 23:26:38 +0000 | [diff] [blame] | 182 | <li><a href="#i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li> |
Chris Lattner | 8a886be | 2006-01-16 22:34:14 +0000 | [diff] [blame] | 183 | <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li> |
| 184 | <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li> |
| 185 | <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li> |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 186 | </ol> |
| 187 | </li> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 188 | <li><a href="#int_debugger">Debugger intrinsics</a></li> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 189 | </ol> |
| 190 | </li> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 191 | </ol> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 192 | |
| 193 | <div class="doc_author"> |
| 194 | <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a> |
| 195 | and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 196 | </div> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 197 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 198 | <!-- *********************************************************************** --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 199 | <div class="doc_section"> <a name="abstract">Abstract </a></div> |
| 200 | <!-- *********************************************************************** --> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 201 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 202 | <div class="doc_text"> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 203 | <p>This document is a reference manual for the LLVM assembly language. |
| 204 | LLVM is an SSA based representation that provides type safety, |
| 205 | low-level operations, flexibility, and the capability of representing |
| 206 | 'all' high-level languages cleanly. It is the common code |
| 207 | representation used throughout all phases of the LLVM compilation |
| 208 | strategy.</p> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 209 | </div> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 210 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 211 | <!-- *********************************************************************** --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 212 | <div class="doc_section"> <a name="introduction">Introduction</a> </div> |
| 213 | <!-- *********************************************************************** --> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 214 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 215 | <div class="doc_text"> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 216 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 217 | <p>The LLVM code representation is designed to be used in three |
| 218 | different forms: as an in-memory compiler IR, as an on-disk bytecode |
| 219 | representation (suitable for fast loading by a Just-In-Time compiler), |
| 220 | and as a human readable assembly language representation. This allows |
| 221 | LLVM to provide a powerful intermediate representation for efficient |
| 222 | compiler transformations and analysis, while providing a natural means |
| 223 | to debug and visualize the transformations. The three different forms |
| 224 | of LLVM are all equivalent. This document describes the human readable |
| 225 | representation and notation.</p> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 226 | |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 227 | <p>The LLVM representation aims to be light-weight and low-level |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 228 | while being expressive, typed, and extensible at the same time. It |
| 229 | aims to be a "universal IR" of sorts, by being at a low enough level |
| 230 | that high-level ideas may be cleanly mapped to it (similar to how |
| 231 | microprocessors are "universal IR's", allowing many source languages to |
| 232 | be mapped to them). By providing type information, LLVM can be used as |
| 233 | the target of optimizations: for example, through pointer analysis, it |
| 234 | can be proven that a C automatic variable is never accessed outside of |
| 235 | the current function... allowing it to be promoted to a simple SSA |
| 236 | value instead of a memory location.</p> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 237 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 238 | </div> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 239 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 240 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 241 | <div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 242 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 243 | <div class="doc_text"> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 244 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 245 | <p>It is important to note that this document describes 'well formed' |
| 246 | LLVM assembly language. There is a difference between what the parser |
| 247 | accepts and what is considered 'well formed'. For example, the |
| 248 | following instruction is syntactically okay, but not well formed:</p> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 249 | |
| 250 | <pre> |
| 251 | %x = <a href="#i_add">add</a> int 1, %x |
| 252 | </pre> |
| 253 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 254 | <p>...because the definition of <tt>%x</tt> does not dominate all of |
| 255 | its uses. The LLVM infrastructure provides a verification pass that may |
| 256 | be used to verify that an LLVM module is well formed. This pass is |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 257 | automatically run by the parser after parsing input assembly and by |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 258 | the optimizer before it outputs bytecode. The violations pointed out |
| 259 | by the verifier pass indicate bugs in transformation passes or input to |
| 260 | the parser.</p> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 261 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 262 | <!-- Describe the typesetting conventions here. --> </div> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 263 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 264 | <!-- *********************************************************************** --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 265 | <div class="doc_section"> <a name="identifiers">Identifiers</a> </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 266 | <!-- *********************************************************************** --> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 267 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 268 | <div class="doc_text"> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 269 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 270 | <p>LLVM uses three different forms of identifiers, for different |
| 271 | purposes:</p> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 272 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 273 | <ol> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 274 | <li>Named values are represented as a string of characters with a '%' prefix. |
| 275 | For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual |
| 276 | regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. |
| 277 | Identifiers which require other characters in their names can be surrounded |
| 278 | with quotes. In this way, anything except a <tt>"</tt> character can be used |
| 279 | in a name.</li> |
| 280 | |
| 281 | <li>Unnamed values are represented as an unsigned numeric value with a '%' |
| 282 | prefix. For example, %12, %2, %44.</li> |
| 283 | |
Reid Spencer | cc16dc3 | 2004-12-09 18:02:53 +0000 | [diff] [blame] | 284 | <li>Constants, which are described in a <a href="#constants">section about |
| 285 | constants</a>, below.</li> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 286 | </ol> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 287 | |
| 288 | <p>LLVM requires that values start with a '%' sign for two reasons: Compilers |
| 289 | don't need to worry about name clashes with reserved words, and the set of |
| 290 | reserved words may be expanded in the future without penalty. Additionally, |
| 291 | unnamed identifiers allow a compiler to quickly come up with a temporary |
| 292 | variable without having to avoid symbol table conflicts.</p> |
| 293 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 294 | <p>Reserved words in LLVM are very similar to reserved words in other |
Reid Spencer | 5c0ef47 | 2006-11-11 23:08:07 +0000 | [diff] [blame] | 295 | languages. There are keywords for different opcodes |
| 296 | ('<tt><a href="#i_add">add</a></tt>', |
| 297 | '<tt><a href="#i_bitcast">bitcast</a></tt>', |
| 298 | '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 299 | href="#t_void">void</a></tt>', '<tt><a href="#t_uint">uint</a></tt>', etc...), |
| 300 | and others. These reserved words cannot conflict with variable names, because |
| 301 | none of them start with a '%' character.</p> |
| 302 | |
| 303 | <p>Here is an example of LLVM code to multiply the integer variable |
| 304 | '<tt>%X</tt>' by 8:</p> |
| 305 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 306 | <p>The easy way:</p> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 307 | |
| 308 | <pre> |
| 309 | %result = <a href="#i_mul">mul</a> uint %X, 8 |
| 310 | </pre> |
| 311 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 312 | <p>After strength reduction:</p> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 313 | |
| 314 | <pre> |
| 315 | %result = <a href="#i_shl">shl</a> uint %X, ubyte 3 |
| 316 | </pre> |
| 317 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 318 | <p>And the hard way:</p> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 319 | |
| 320 | <pre> |
| 321 | <a href="#i_add">add</a> uint %X, %X <i>; yields {uint}:%0</i> |
| 322 | <a href="#i_add">add</a> uint %0, %0 <i>; yields {uint}:%1</i> |
| 323 | %result = <a href="#i_add">add</a> uint %1, %1 |
| 324 | </pre> |
| 325 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 326 | <p>This last way of multiplying <tt>%X</tt> by 8 illustrates several |
| 327 | important lexical features of LLVM:</p> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 328 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 329 | <ol> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 330 | |
| 331 | <li>Comments are delimited with a '<tt>;</tt>' and go until the end of |
| 332 | line.</li> |
| 333 | |
| 334 | <li>Unnamed temporaries are created when the result of a computation is not |
| 335 | assigned to a named value.</li> |
| 336 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 337 | <li>Unnamed temporaries are numbered sequentially</li> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 338 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 339 | </ol> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 340 | |
John Criswell | e4c57cc | 2005-05-12 16:52:32 +0000 | [diff] [blame] | 341 | <p>...and it also shows a convention that we follow in this document. When |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 342 | demonstrating instructions, we will follow an instruction with a comment that |
| 343 | defines the type and name of value produced. Comments are shown in italic |
| 344 | text.</p> |
| 345 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 346 | </div> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 347 | |
| 348 | <!-- *********************************************************************** --> |
| 349 | <div class="doc_section"> <a name="highlevel">High Level Structure</a> </div> |
| 350 | <!-- *********************************************************************** --> |
| 351 | |
| 352 | <!-- ======================================================================= --> |
| 353 | <div class="doc_subsection"> <a name="modulestructure">Module Structure</a> |
| 354 | </div> |
| 355 | |
| 356 | <div class="doc_text"> |
| 357 | |
| 358 | <p>LLVM programs are composed of "Module"s, each of which is a |
| 359 | translation unit of the input programs. Each module consists of |
| 360 | functions, global variables, and symbol table entries. Modules may be |
| 361 | combined together with the LLVM linker, which merges function (and |
| 362 | global variable) definitions, resolves forward declarations, and merges |
| 363 | symbol table entries. Here is an example of the "hello world" module:</p> |
| 364 | |
| 365 | <pre><i>; Declare the string constant as a global constant...</i> |
| 366 | <a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a |
| 367 | href="#globalvars">constant</a> <a href="#t_array">[13 x sbyte]</a> c"hello world\0A\00" <i>; [13 x sbyte]*</i> |
| 368 | |
| 369 | <i>; External declaration of the puts function</i> |
| 370 | <a href="#functionstructure">declare</a> int %puts(sbyte*) <i>; int(sbyte*)* </i> |
| 371 | |
Chris Lattner | 81c01f0 | 2006-06-13 03:05:47 +0000 | [diff] [blame] | 372 | <i>; Global variable / Function body section separator</i> |
| 373 | implementation |
| 374 | |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 375 | <i>; Definition of main function</i> |
| 376 | int %main() { <i>; int()* </i> |
| 377 | <i>; Convert [13x sbyte]* to sbyte *...</i> |
| 378 | %cast210 = <a |
| 379 | href="#i_getelementptr">getelementptr</a> [13 x sbyte]* %.LC0, long 0, long 0 <i>; sbyte*</i> |
| 380 | |
| 381 | <i>; Call puts function to write out the string to stdout...</i> |
| 382 | <a |
| 383 | href="#i_call">call</a> int %puts(sbyte* %cast210) <i>; int</i> |
| 384 | <a |
| 385 | href="#i_ret">ret</a> int 0<br>}<br></pre> |
| 386 | |
| 387 | <p>This example is made up of a <a href="#globalvars">global variable</a> |
| 388 | named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" |
| 389 | function, and a <a href="#functionstructure">function definition</a> |
| 390 | for "<tt>main</tt>".</p> |
| 391 | |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 392 | <p>In general, a module is made up of a list of global values, |
| 393 | where both functions and global variables are global values. Global values are |
| 394 | represented by a pointer to a memory location (in this case, a pointer to an |
| 395 | array of char, and a pointer to a function), and have one of the following <a |
| 396 | href="#linkage">linkage types</a>.</p> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 397 | |
Chris Lattner | 81c01f0 | 2006-06-13 03:05:47 +0000 | [diff] [blame] | 398 | <p>Due to a limitation in the current LLVM assembly parser (it is limited by |
| 399 | one-token lookahead), modules are split into two pieces by the "implementation" |
| 400 | keyword. Global variable prototypes and definitions must occur before the |
| 401 | keyword, and function definitions must occur after it. Function prototypes may |
| 402 | occur either before or after it. In the future, the implementation keyword may |
| 403 | become a noop, if the parser gets smarter.</p> |
| 404 | |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 405 | </div> |
| 406 | |
| 407 | <!-- ======================================================================= --> |
| 408 | <div class="doc_subsection"> |
| 409 | <a name="linkage">Linkage Types</a> |
| 410 | </div> |
| 411 | |
| 412 | <div class="doc_text"> |
| 413 | |
| 414 | <p> |
| 415 | All Global Variables and Functions have one of the following types of linkage: |
| 416 | </p> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 417 | |
| 418 | <dl> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 419 | |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 420 | <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 421 | |
| 422 | <dd>Global values with internal linkage are only directly accessible by |
| 423 | objects in the current module. In particular, linking code into a module with |
| 424 | an internal global value may cause the internal to be renamed as necessary to |
| 425 | avoid collisions. Because the symbol is internal to the module, all |
| 426 | references can be updated. This corresponds to the notion of the |
| 427 | '<tt>static</tt>' keyword in C, or the idea of "anonymous namespaces" in C++. |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 428 | </dd> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 429 | |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 430 | <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 431 | |
| 432 | <dd>"<tt>linkonce</tt>" linkage is similar to <tt>internal</tt> linkage, with |
| 433 | the twist that linking together two modules defining the same |
| 434 | <tt>linkonce</tt> globals will cause one of the globals to be discarded. This |
| 435 | is typically used to implement inline functions. Unreferenced |
| 436 | <tt>linkonce</tt> globals are allowed to be discarded. |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 437 | </dd> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 438 | |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 439 | <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 440 | |
| 441 | <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage, |
| 442 | except that unreferenced <tt>weak</tt> globals may not be discarded. This is |
| 443 | used to implement constructs in C such as "<tt>int X;</tt>" at global scope. |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 444 | </dd> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 445 | |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 446 | <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 447 | |
| 448 | <dd>"<tt>appending</tt>" linkage may only be applied to global variables of |
| 449 | pointer to array type. When two global variables with appending linkage are |
| 450 | linked together, the two global arrays are appended together. This is the |
| 451 | LLVM, typesafe, equivalent of having the system linker append together |
| 452 | "sections" with identical names when .o files are linked. |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 453 | </dd> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 454 | |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 455 | <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 456 | |
| 457 | <dd>If none of the above identifiers are used, the global is externally |
| 458 | visible, meaning that it participates in linkage and can be used to resolve |
| 459 | external symbol references. |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 460 | </dd> |
Anton Korobeynikov | b74ed07 | 2006-09-14 18:23:27 +0000 | [diff] [blame] | 461 | |
| 462 | <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt> |
| 463 | |
| 464 | <dd>"<tt>extern_weak</tt>" TBD |
| 465 | </dd> |
| 466 | |
| 467 | <p> |
| 468 | The next two types of linkage are targeted for Microsoft Windows platform |
| 469 | only. They are designed to support importing (exporting) symbols from (to) |
| 470 | DLLs. |
| 471 | </p> |
| 472 | |
| 473 | <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt> |
| 474 | |
| 475 | <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function |
| 476 | or variable via a global pointer to a pointer that is set up by the DLL |
| 477 | exporting the symbol. On Microsoft Windows targets, the pointer name is |
| 478 | formed by combining <code>_imp__</code> and the function or variable name. |
| 479 | </dd> |
| 480 | |
| 481 | <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt> |
| 482 | |
| 483 | <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global |
| 484 | pointer to a pointer in a DLL, so that it can be referenced with the |
| 485 | <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer |
| 486 | name is formed by combining <code>_imp__</code> and the function or variable |
| 487 | name. |
| 488 | </dd> |
| 489 | |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 490 | </dl> |
| 491 | |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 492 | <p><a name="linkage_external">For example, since the "<tt>.LC0</tt>" |
| 493 | variable is defined to be internal, if another module defined a "<tt>.LC0</tt>" |
| 494 | variable and was linked with this one, one of the two would be renamed, |
| 495 | preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are |
| 496 | external (i.e., lacking any linkage declarations), they are accessible |
| 497 | outside of the current module. It is illegal for a function <i>declaration</i> |
| 498 | to have any linkage type other than "externally visible".</a></p> |
Chris Lattner | e5d947b | 2004-12-09 16:36:40 +0000 | [diff] [blame] | 499 | |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 500 | </div> |
| 501 | |
| 502 | <!-- ======================================================================= --> |
| 503 | <div class="doc_subsection"> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 504 | <a name="callingconv">Calling Conventions</a> |
| 505 | </div> |
| 506 | |
| 507 | <div class="doc_text"> |
| 508 | |
| 509 | <p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a> |
| 510 | and <a href="#i_invoke">invokes</a> can all have an optional calling convention |
| 511 | specified for the call. The calling convention of any pair of dynamic |
| 512 | caller/callee must match, or the behavior of the program is undefined. The |
| 513 | following calling conventions are supported by LLVM, and more may be added in |
| 514 | the future:</p> |
| 515 | |
| 516 | <dl> |
| 517 | <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt> |
| 518 | |
| 519 | <dd>This calling convention (the default if no other calling convention is |
| 520 | specified) matches the target C calling conventions. This calling convention |
John Criswell | e4c57cc | 2005-05-12 16:52:32 +0000 | [diff] [blame] | 521 | supports varargs function calls and tolerates some mismatch in the declared |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 522 | prototype and implemented declaration of the function (as does normal C). |
| 523 | </dd> |
| 524 | |
Chris Lattner | 5710ce9 | 2006-05-19 21:15:36 +0000 | [diff] [blame] | 525 | <dt><b>"<tt>csretcc</tt>" - The C struct return calling convention</b>:</dt> |
| 526 | |
| 527 | <dd>This calling convention matches the target C calling conventions, except |
| 528 | that functions with this convention are required to take a pointer as their |
| 529 | first argument, and the return type of the function must be void. This is |
| 530 | used for C functions that return aggregates by-value. In this case, the |
| 531 | function has been transformed to take a pointer to the struct as the first |
| 532 | argument to the function. For targets where the ABI specifies specific |
| 533 | behavior for structure-return calls, the calling convention can be used to |
| 534 | distinguish between struct return functions and other functions that take a |
| 535 | pointer to a struct as the first argument. |
| 536 | </dd> |
| 537 | |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 538 | <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt> |
| 539 | |
| 540 | <dd>This calling convention attempts to make calls as fast as possible |
| 541 | (e.g. by passing things in registers). This calling convention allows the |
| 542 | target to use whatever tricks it wants to produce fast code for the target, |
Chris Lattner | 8cdc5bc | 2005-05-06 23:08:23 +0000 | [diff] [blame] | 543 | without having to conform to an externally specified ABI. Implementations of |
| 544 | this convention should allow arbitrary tail call optimization to be supported. |
| 545 | This calling convention does not support varargs and requires the prototype of |
| 546 | all callees to exactly match the prototype of the function definition. |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 547 | </dd> |
| 548 | |
| 549 | <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt> |
| 550 | |
| 551 | <dd>This calling convention attempts to make code in the caller as efficient |
| 552 | as possible under the assumption that the call is not commonly executed. As |
| 553 | such, these calls often preserve all registers so that the call does not break |
| 554 | any live ranges in the caller side. This calling convention does not support |
| 555 | varargs and requires the prototype of all callees to exactly match the |
| 556 | prototype of the function definition. |
| 557 | </dd> |
| 558 | |
Chris Lattner | cfe6b37 | 2005-05-07 01:46:40 +0000 | [diff] [blame] | 559 | <dt><b>"<tt>cc <<em>n</em>></tt>" - Numbered convention</b>:</dt> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 560 | |
| 561 | <dd>Any calling convention may be specified by number, allowing |
| 562 | target-specific calling conventions to be used. Target specific calling |
| 563 | conventions start at 64. |
| 564 | </dd> |
Chris Lattner | cfe6b37 | 2005-05-07 01:46:40 +0000 | [diff] [blame] | 565 | </dl> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 566 | |
| 567 | <p>More calling conventions can be added/defined on an as-needed basis, to |
| 568 | support pascal conventions or any other well-known target-independent |
| 569 | convention.</p> |
| 570 | |
| 571 | </div> |
| 572 | |
| 573 | <!-- ======================================================================= --> |
| 574 | <div class="doc_subsection"> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 575 | <a name="globalvars">Global Variables</a> |
| 576 | </div> |
| 577 | |
| 578 | <div class="doc_text"> |
| 579 | |
Chris Lattner | 3689a34 | 2005-02-12 19:30:21 +0000 | [diff] [blame] | 580 | <p>Global variables define regions of memory allocated at compilation time |
Chris Lattner | 88f6c46 | 2005-11-12 00:45:07 +0000 | [diff] [blame] | 581 | instead of run-time. Global variables may optionally be initialized, may have |
| 582 | an explicit section to be placed in, and may |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 583 | have an optional explicit alignment specified. A |
John Criswell | 0ec250c | 2005-10-24 16:17:18 +0000 | [diff] [blame] | 584 | variable may be defined as a global "constant," which indicates that the |
Chris Lattner | 3689a34 | 2005-02-12 19:30:21 +0000 | [diff] [blame] | 585 | contents of the variable will <b>never</b> be modified (enabling better |
| 586 | optimization, allowing the global data to be placed in the read-only section of |
| 587 | an executable, etc). Note that variables that need runtime initialization |
John Criswell | 0ec250c | 2005-10-24 16:17:18 +0000 | [diff] [blame] | 588 | cannot be marked "constant" as there is a store to the variable.</p> |
Chris Lattner | 3689a34 | 2005-02-12 19:30:21 +0000 | [diff] [blame] | 589 | |
| 590 | <p> |
| 591 | LLVM explicitly allows <em>declarations</em> of global variables to be marked |
| 592 | constant, even if the final definition of the global is not. This capability |
| 593 | can be used to enable slightly better optimization of the program, but requires |
| 594 | the language definition to guarantee that optimizations based on the |
| 595 | 'constantness' are valid for the translation units that do not include the |
| 596 | definition. |
| 597 | </p> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 598 | |
| 599 | <p>As SSA values, global variables define pointer values that are in |
| 600 | scope (i.e. they dominate) all basic blocks in the program. Global |
| 601 | variables always define a pointer to their "content" type because they |
| 602 | describe a region of memory, and all memory objects in LLVM are |
| 603 | accessed through pointers.</p> |
| 604 | |
Chris Lattner | 88f6c46 | 2005-11-12 00:45:07 +0000 | [diff] [blame] | 605 | <p>LLVM allows an explicit section to be specified for globals. If the target |
| 606 | supports it, it will emit globals to the section specified.</p> |
| 607 | |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 608 | <p>An explicit alignment may be specified for a global. If not present, or if |
| 609 | the alignment is set to zero, the alignment of the global is set by the target |
| 610 | to whatever it feels convenient. If an explicit alignment is specified, the |
| 611 | global is forced to have at least that much alignment. All alignments must be |
| 612 | a power of 2.</p> |
| 613 | |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 614 | </div> |
| 615 | |
| 616 | |
| 617 | <!-- ======================================================================= --> |
| 618 | <div class="doc_subsection"> |
| 619 | <a name="functionstructure">Functions</a> |
| 620 | </div> |
| 621 | |
| 622 | <div class="doc_text"> |
| 623 | |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 624 | <p>LLVM function definitions consist of an optional <a href="#linkage">linkage |
| 625 | type</a>, an optional <a href="#callingconv">calling convention</a>, a return |
Chris Lattner | 88f6c46 | 2005-11-12 00:45:07 +0000 | [diff] [blame] | 626 | type, a function name, a (possibly empty) argument list, an optional section, |
| 627 | an optional alignment, an opening curly brace, |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 628 | a list of basic blocks, and a closing curly brace. LLVM function declarations |
| 629 | are defined with the "<tt>declare</tt>" keyword, an optional <a |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 630 | href="#callingconv">calling convention</a>, a return type, a function name, |
| 631 | a possibly empty list of arguments, and an optional alignment.</p> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 632 | |
| 633 | <p>A function definition contains a list of basic blocks, forming the CFG for |
| 634 | the function. Each basic block may optionally start with a label (giving the |
| 635 | basic block a symbol table entry), contains a list of instructions, and ends |
| 636 | with a <a href="#terminators">terminator</a> instruction (such as a branch or |
| 637 | function return).</p> |
| 638 | |
John Criswell | e4c57cc | 2005-05-12 16:52:32 +0000 | [diff] [blame] | 639 | <p>The first basic block in a program is special in two ways: it is immediately |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 640 | executed on entrance to the function, and it is not allowed to have predecessor |
| 641 | basic blocks (i.e. there can not be any branches to the entry block of a |
| 642 | function). Because the block can have no predecessors, it also cannot have any |
| 643 | <a href="#i_phi">PHI nodes</a>.</p> |
| 644 | |
| 645 | <p>LLVM functions are identified by their name and type signature. Hence, two |
| 646 | functions with the same name but different parameter lists or return values are |
Chris Lattner | d4f6b17 | 2005-03-07 22:13:59 +0000 | [diff] [blame] | 647 | considered different functions, and LLVM will resolve references to each |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 648 | appropriately.</p> |
| 649 | |
Chris Lattner | 88f6c46 | 2005-11-12 00:45:07 +0000 | [diff] [blame] | 650 | <p>LLVM allows an explicit section to be specified for functions. If the target |
| 651 | supports it, it will emit functions to the section specified.</p> |
| 652 | |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 653 | <p>An explicit alignment may be specified for a function. If not present, or if |
| 654 | the alignment is set to zero, the alignment of the function is set by the target |
| 655 | to whatever it feels convenient. If an explicit alignment is specified, the |
| 656 | function is forced to have at least that much alignment. All alignments must be |
| 657 | a power of 2.</p> |
| 658 | |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 659 | </div> |
| 660 | |
Chris Lattner | 4e9aba7 | 2006-01-23 23:23:47 +0000 | [diff] [blame] | 661 | <!-- ======================================================================= --> |
| 662 | <div class="doc_subsection"> |
Chris Lattner | 1eeeb0c | 2006-04-08 04:40:53 +0000 | [diff] [blame] | 663 | <a name="moduleasm">Module-Level Inline Assembly</a> |
Chris Lattner | 4e9aba7 | 2006-01-23 23:23:47 +0000 | [diff] [blame] | 664 | </div> |
| 665 | |
| 666 | <div class="doc_text"> |
| 667 | <p> |
| 668 | Modules may contain "module-level inline asm" blocks, which corresponds to the |
| 669 | GCC "file scope inline asm" blocks. These blocks are internally concatenated by |
| 670 | LLVM and treated as a single unit, but may be separated in the .ll file if |
| 671 | desired. The syntax is very simple: |
| 672 | </p> |
| 673 | |
| 674 | <div class="doc_code"><pre> |
Chris Lattner | 52599e1 | 2006-01-24 00:37:20 +0000 | [diff] [blame] | 675 | module asm "inline asm code goes here" |
| 676 | module asm "more can go here" |
Chris Lattner | 4e9aba7 | 2006-01-23 23:23:47 +0000 | [diff] [blame] | 677 | </pre></div> |
| 678 | |
| 679 | <p>The strings can contain any character by escaping non-printable characters. |
| 680 | The escape sequence used is simply "\xx" where "xx" is the two digit hex code |
| 681 | for the number. |
| 682 | </p> |
| 683 | |
| 684 | <p> |
| 685 | The inline asm code is simply printed to the machine code .s file when |
| 686 | assembly code is generated. |
| 687 | </p> |
| 688 | </div> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 689 | |
| 690 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 691 | <!-- *********************************************************************** --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 692 | <div class="doc_section"> <a name="typesystem">Type System</a> </div> |
| 693 | <!-- *********************************************************************** --> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 694 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 695 | <div class="doc_text"> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 696 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 697 | <p>The LLVM type system is one of the most important features of the |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 698 | intermediate representation. Being typed enables a number of |
| 699 | optimizations to be performed on the IR directly, without having to do |
| 700 | extra analyses on the side before the transformation. A strong type |
| 701 | system makes it easier to read the generated code and enables novel |
| 702 | analyses and transformations that are not feasible to perform on normal |
| 703 | three address code representations.</p> |
Chris Lattner | fa73021 | 2004-12-09 16:11:40 +0000 | [diff] [blame] | 704 | |
| 705 | </div> |
| 706 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 707 | <!-- ======================================================================= --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 708 | <div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 709 | <div class="doc_text"> |
John Criswell | 4457dc9 | 2004-04-09 16:48:45 +0000 | [diff] [blame] | 710 | <p>The primitive types are the fundamental building blocks of the LLVM |
Chris Lattner | d4f6b17 | 2005-03-07 22:13:59 +0000 | [diff] [blame] | 711 | system. The current set of primitive types is as follows:</p> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 712 | |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 713 | <table class="layout"> |
| 714 | <tr class="layout"> |
| 715 | <td class="left"> |
| 716 | <table> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 717 | <tbody> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 718 | <tr><th>Type</th><th>Description</th></tr> |
| 719 | <tr><td><tt>void</tt></td><td>No value</td></tr> |
Misha Brukman | cfa87bc | 2005-04-22 18:02:52 +0000 | [diff] [blame] | 720 | <tr><td><tt>ubyte</tt></td><td>Unsigned 8-bit value</td></tr> |
| 721 | <tr><td><tt>ushort</tt></td><td>Unsigned 16-bit value</td></tr> |
| 722 | <tr><td><tt>uint</tt></td><td>Unsigned 32-bit value</td></tr> |
| 723 | <tr><td><tt>ulong</tt></td><td>Unsigned 64-bit value</td></tr> |
| 724 | <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 725 | <tr><td><tt>label</tt></td><td>Branch destination</td></tr> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 726 | </tbody> |
| 727 | </table> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 728 | </td> |
| 729 | <td class="right"> |
| 730 | <table> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 731 | <tbody> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 732 | <tr><th>Type</th><th>Description</th></tr> |
| 733 | <tr><td><tt>bool</tt></td><td>True or False value</td></tr> |
Misha Brukman | cfa87bc | 2005-04-22 18:02:52 +0000 | [diff] [blame] | 734 | <tr><td><tt>sbyte</tt></td><td>Signed 8-bit value</td></tr> |
| 735 | <tr><td><tt>short</tt></td><td>Signed 16-bit value</td></tr> |
| 736 | <tr><td><tt>int</tt></td><td>Signed 32-bit value</td></tr> |
| 737 | <tr><td><tt>long</tt></td><td>Signed 64-bit value</td></tr> |
| 738 | <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 739 | </tbody> |
| 740 | </table> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 741 | </td> |
| 742 | </tr> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 743 | </table> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 744 | </div> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 745 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 746 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 747 | <div class="doc_subsubsection"> <a name="t_classifications">Type |
| 748 | Classifications</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 749 | <div class="doc_text"> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 750 | <p>These different primitive types fall into a few useful |
| 751 | classifications:</p> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 752 | |
| 753 | <table border="1" cellspacing="0" cellpadding="4"> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 754 | <tbody> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 755 | <tr><th>Classification</th><th>Types</th></tr> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 756 | <tr> |
| 757 | <td><a name="t_signed">signed</a></td> |
| 758 | <td><tt>sbyte, short, int, long, float, double</tt></td> |
| 759 | </tr> |
| 760 | <tr> |
| 761 | <td><a name="t_unsigned">unsigned</a></td> |
| 762 | <td><tt>ubyte, ushort, uint, ulong</tt></td> |
| 763 | </tr> |
| 764 | <tr> |
| 765 | <td><a name="t_integer">integer</a></td> |
| 766 | <td><tt>ubyte, sbyte, ushort, short, uint, int, ulong, long</tt></td> |
| 767 | </tr> |
| 768 | <tr> |
| 769 | <td><a name="t_integral">integral</a></td> |
Misha Brukman | c24b758 | 2004-08-12 20:16:08 +0000 | [diff] [blame] | 770 | <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long</tt> |
| 771 | </td> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 772 | </tr> |
| 773 | <tr> |
| 774 | <td><a name="t_floating">floating point</a></td> |
| 775 | <td><tt>float, double</tt></td> |
| 776 | </tr> |
| 777 | <tr> |
| 778 | <td><a name="t_firstclass">first class</a></td> |
Misha Brukman | c24b758 | 2004-08-12 20:16:08 +0000 | [diff] [blame] | 779 | <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long,<br> |
| 780 | float, double, <a href="#t_pointer">pointer</a>, |
| 781 | <a href="#t_packed">packed</a></tt></td> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 782 | </tr> |
| 783 | </tbody> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 784 | </table> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 785 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 786 | <p>The <a href="#t_firstclass">first class</a> types are perhaps the |
| 787 | most important. Values of these types are the only ones which can be |
| 788 | produced by instructions, passed as arguments, or used as operands to |
| 789 | instructions. This means that all structures and arrays must be |
| 790 | manipulated either by pointer or by component.</p> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 791 | </div> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 792 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 793 | <!-- ======================================================================= --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 794 | <div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 795 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 796 | <div class="doc_text"> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 797 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 798 | <p>The real power in LLVM comes from the derived types in the system. |
| 799 | This is what allows a programmer to represent arrays, functions, |
| 800 | pointers, and other useful types. Note that these derived types may be |
| 801 | recursive: For example, it is possible to have a two dimensional array.</p> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 802 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 803 | </div> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 804 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 805 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 806 | <div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 807 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 808 | <div class="doc_text"> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 809 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 810 | <h5>Overview:</h5> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 811 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 812 | <p>The array type is a very simple derived type that arranges elements |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 813 | sequentially in memory. The array type requires a size (number of |
| 814 | elements) and an underlying data type.</p> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 815 | |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 816 | <h5>Syntax:</h5> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 817 | |
| 818 | <pre> |
| 819 | [<# elements> x <elementtype>] |
| 820 | </pre> |
| 821 | |
John Criswell | e4c57cc | 2005-05-12 16:52:32 +0000 | [diff] [blame] | 822 | <p>The number of elements is a constant integer value; elementtype may |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 823 | be any type with a size.</p> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 824 | |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 825 | <h5>Examples:</h5> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 826 | <table class="layout"> |
| 827 | <tr class="layout"> |
| 828 | <td class="left"> |
| 829 | <tt>[40 x int ]</tt><br/> |
| 830 | <tt>[41 x int ]</tt><br/> |
| 831 | <tt>[40 x uint]</tt><br/> |
| 832 | </td> |
| 833 | <td class="left"> |
| 834 | Array of 40 integer values.<br/> |
| 835 | Array of 41 integer values.<br/> |
| 836 | Array of 40 unsigned integer values.<br/> |
| 837 | </td> |
| 838 | </tr> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 839 | </table> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 840 | <p>Here are some examples of multidimensional arrays:</p> |
| 841 | <table class="layout"> |
| 842 | <tr class="layout"> |
| 843 | <td class="left"> |
| 844 | <tt>[3 x [4 x int]]</tt><br/> |
| 845 | <tt>[12 x [10 x float]]</tt><br/> |
| 846 | <tt>[2 x [3 x [4 x uint]]]</tt><br/> |
| 847 | </td> |
| 848 | <td class="left"> |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 849 | 3x4 array of integer values.<br/> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 850 | 12x10 array of single precision floating point values.<br/> |
| 851 | 2x3x4 array of unsigned integer values.<br/> |
| 852 | </td> |
| 853 | </tr> |
| 854 | </table> |
Chris Lattner | e67a951 | 2005-06-24 17:22:57 +0000 | [diff] [blame] | 855 | |
John Criswell | 0ec250c | 2005-10-24 16:17:18 +0000 | [diff] [blame] | 856 | <p>Note that 'variable sized arrays' can be implemented in LLVM with a zero |
| 857 | length array. Normally, accesses past the end of an array are undefined in |
Chris Lattner | e67a951 | 2005-06-24 17:22:57 +0000 | [diff] [blame] | 858 | LLVM (e.g. it is illegal to access the 5th element of a 3 element array). |
| 859 | As a special case, however, zero length arrays are recognized to be variable |
| 860 | length. This allows implementation of 'pascal style arrays' with the LLVM |
| 861 | type "{ int, [0 x float]}", for example.</p> |
| 862 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 863 | </div> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 864 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 865 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 866 | <div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 867 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 868 | <h5>Overview:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 869 | <p>The function type can be thought of as a function signature. It |
| 870 | consists of a return type and a list of formal parameter types. |
John Criswell | 009900b | 2003-11-25 21:45:46 +0000 | [diff] [blame] | 871 | Function types are usually used to build virtual function tables |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 872 | (which are structures of pointers to functions), for indirect function |
| 873 | calls, and when defining a function.</p> |
John Criswell | 009900b | 2003-11-25 21:45:46 +0000 | [diff] [blame] | 874 | <p> |
| 875 | The return type of a function type cannot be an aggregate type. |
| 876 | </p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 877 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 878 | <pre> <returntype> (<parameter list>)<br></pre> |
John Criswell | 0ec250c | 2005-10-24 16:17:18 +0000 | [diff] [blame] | 879 | <p>...where '<tt><parameter list></tt>' is a comma-separated list of type |
Misha Brukman | c24b758 | 2004-08-12 20:16:08 +0000 | [diff] [blame] | 880 | specifiers. Optionally, the parameter list may include a type <tt>...</tt>, |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 881 | which indicates that the function takes a variable number of arguments. |
| 882 | Variable argument functions can access their arguments with the <a |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 883 | href="#int_varargs">variable argument handling intrinsic</a> functions.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 884 | <h5>Examples:</h5> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 885 | <table class="layout"> |
| 886 | <tr class="layout"> |
| 887 | <td class="left"> |
| 888 | <tt>int (int)</tt> <br/> |
| 889 | <tt>float (int, int *) *</tt><br/> |
| 890 | <tt>int (sbyte *, ...)</tt><br/> |
| 891 | </td> |
| 892 | <td class="left"> |
| 893 | function taking an <tt>int</tt>, returning an <tt>int</tt><br/> |
| 894 | <a href="#t_pointer">Pointer</a> to a function that takes an |
Misha Brukman | c24b758 | 2004-08-12 20:16:08 +0000 | [diff] [blame] | 895 | <tt>int</tt> and a <a href="#t_pointer">pointer</a> to <tt>int</tt>, |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 896 | returning <tt>float</tt>.<br/> |
| 897 | A vararg function that takes at least one <a href="#t_pointer">pointer</a> |
| 898 | to <tt>sbyte</tt> (signed char in C), which returns an integer. This is |
| 899 | the signature for <tt>printf</tt> in LLVM.<br/> |
| 900 | </td> |
| 901 | </tr> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 902 | </table> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 903 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 904 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 905 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 906 | <div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 907 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 908 | <h5>Overview:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 909 | <p>The structure type is used to represent a collection of data members |
| 910 | together in memory. The packing of the field types is defined to match |
| 911 | the ABI of the underlying processor. The elements of a structure may |
| 912 | be any type that has a size.</p> |
| 913 | <p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> |
| 914 | and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a |
| 915 | field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' |
| 916 | instruction.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 917 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 918 | <pre> { <type list> }<br></pre> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 919 | <h5>Examples:</h5> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 920 | <table class="layout"> |
| 921 | <tr class="layout"> |
| 922 | <td class="left"> |
| 923 | <tt>{ int, int, int }</tt><br/> |
| 924 | <tt>{ float, int (int) * }</tt><br/> |
| 925 | </td> |
| 926 | <td class="left"> |
| 927 | a triple of three <tt>int</tt> values<br/> |
| 928 | A pair, where the first element is a <tt>float</tt> and the second element |
| 929 | is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a> |
| 930 | that takes an <tt>int</tt>, returning an <tt>int</tt>.<br/> |
| 931 | </td> |
| 932 | </tr> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 933 | </table> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 934 | </div> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 935 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 936 | <!-- _______________________________________________________________________ --> |
Andrew Lenharth | 75e1068 | 2006-12-08 17:13:00 +0000 | [diff] [blame^] | 937 | <div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a> |
| 938 | </div> |
| 939 | <div class="doc_text"> |
| 940 | <h5>Overview:</h5> |
| 941 | <p>The packed structure type is used to represent a collection of data members |
| 942 | together in memory. There is no padding between fields. Further, the alignment |
| 943 | of a packed structure is 1 byte. The elements of a packed structure may |
| 944 | be any type that has a size.</p> |
| 945 | <p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> |
| 946 | and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a |
| 947 | field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' |
| 948 | instruction.</p> |
| 949 | <h5>Syntax:</h5> |
| 950 | <pre> < { <type list> } > <br></pre> |
| 951 | <h5>Examples:</h5> |
| 952 | <table class="layout"> |
| 953 | <tr class="layout"> |
| 954 | <td class="left"> |
| 955 | <tt> < { int, int, int } > </tt><br/> |
| 956 | <tt> < { float, int (int) * } > </tt><br/> |
| 957 | </td> |
| 958 | <td class="left"> |
| 959 | a triple of three <tt>int</tt> values<br/> |
| 960 | A pair, where the first element is a <tt>float</tt> and the second element |
| 961 | is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a> |
| 962 | that takes an <tt>int</tt>, returning an <tt>int</tt>.<br/> |
| 963 | </td> |
| 964 | </tr> |
| 965 | </table> |
| 966 | </div> |
| 967 | |
| 968 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 969 | <div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 970 | <div class="doc_text"> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 971 | <h5>Overview:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 972 | <p>As in many languages, the pointer type represents a pointer or |
| 973 | reference to another object, which must live in memory.</p> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 974 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 975 | <pre> <type> *<br></pre> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 976 | <h5>Examples:</h5> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 977 | <table class="layout"> |
| 978 | <tr class="layout"> |
| 979 | <td class="left"> |
| 980 | <tt>[4x int]*</tt><br/> |
| 981 | <tt>int (int *) *</tt><br/> |
| 982 | </td> |
| 983 | <td class="left"> |
| 984 | A <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of |
| 985 | four <tt>int</tt> values<br/> |
| 986 | A <a href="#t_pointer">pointer</a> to a <a |
Chris Lattner | a977c48 | 2005-02-19 02:22:14 +0000 | [diff] [blame] | 987 | href="#t_function">function</a> that takes an <tt>int*</tt>, returning an |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 988 | <tt>int</tt>.<br/> |
| 989 | </td> |
| 990 | </tr> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 991 | </table> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 992 | </div> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 993 | |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 994 | <!-- _______________________________________________________________________ --> |
| 995 | <div class="doc_subsubsection"> <a name="t_packed">Packed Type</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 996 | <div class="doc_text"> |
Chris Lattner | 69c11bb | 2005-04-25 17:34:15 +0000 | [diff] [blame] | 997 | |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 998 | <h5>Overview:</h5> |
Chris Lattner | 69c11bb | 2005-04-25 17:34:15 +0000 | [diff] [blame] | 999 | |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 1000 | <p>A packed type is a simple derived type that represents a vector |
| 1001 | of elements. Packed types are used when multiple primitive data |
| 1002 | are operated in parallel using a single instruction (SIMD). |
| 1003 | A packed type requires a size (number of |
Chris Lattner | b8d172f | 2005-11-10 01:44:22 +0000 | [diff] [blame] | 1004 | elements) and an underlying primitive data type. Vectors must have a power |
| 1005 | of two length (1, 2, 4, 8, 16 ...). Packed types are |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 1006 | considered <a href="#t_firstclass">first class</a>.</p> |
Chris Lattner | 69c11bb | 2005-04-25 17:34:15 +0000 | [diff] [blame] | 1007 | |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 1008 | <h5>Syntax:</h5> |
Chris Lattner | 69c11bb | 2005-04-25 17:34:15 +0000 | [diff] [blame] | 1009 | |
| 1010 | <pre> |
| 1011 | < <# elements> x <elementtype> > |
| 1012 | </pre> |
| 1013 | |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 1014 | <p>The number of elements is a constant integer value; elementtype may |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 1015 | be any integral or floating point type.</p> |
Chris Lattner | 69c11bb | 2005-04-25 17:34:15 +0000 | [diff] [blame] | 1016 | |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 1017 | <h5>Examples:</h5> |
Chris Lattner | 69c11bb | 2005-04-25 17:34:15 +0000 | [diff] [blame] | 1018 | |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 1019 | <table class="layout"> |
| 1020 | <tr class="layout"> |
| 1021 | <td class="left"> |
| 1022 | <tt><4 x int></tt><br/> |
| 1023 | <tt><8 x float></tt><br/> |
| 1024 | <tt><2 x uint></tt><br/> |
| 1025 | </td> |
| 1026 | <td class="left"> |
| 1027 | Packed vector of 4 integer values.<br/> |
| 1028 | Packed vector of 8 floating-point values.<br/> |
| 1029 | Packed vector of 2 unsigned integer values.<br/> |
| 1030 | </td> |
| 1031 | </tr> |
| 1032 | </table> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1033 | </div> |
| 1034 | |
Chris Lattner | 69c11bb | 2005-04-25 17:34:15 +0000 | [diff] [blame] | 1035 | <!-- _______________________________________________________________________ --> |
| 1036 | <div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div> |
| 1037 | <div class="doc_text"> |
| 1038 | |
| 1039 | <h5>Overview:</h5> |
| 1040 | |
| 1041 | <p>Opaque types are used to represent unknown types in the system. This |
| 1042 | corresponds (for example) to the C notion of a foward declared structure type. |
| 1043 | In LLVM, opaque types can eventually be resolved to any type (not just a |
| 1044 | structure type).</p> |
| 1045 | |
| 1046 | <h5>Syntax:</h5> |
| 1047 | |
| 1048 | <pre> |
| 1049 | opaque |
| 1050 | </pre> |
| 1051 | |
| 1052 | <h5>Examples:</h5> |
| 1053 | |
| 1054 | <table class="layout"> |
| 1055 | <tr class="layout"> |
| 1056 | <td class="left"> |
| 1057 | <tt>opaque</tt> |
| 1058 | </td> |
| 1059 | <td class="left"> |
| 1060 | An opaque type.<br/> |
| 1061 | </td> |
| 1062 | </tr> |
| 1063 | </table> |
| 1064 | </div> |
| 1065 | |
| 1066 | |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1067 | <!-- *********************************************************************** --> |
| 1068 | <div class="doc_section"> <a name="constants">Constants</a> </div> |
| 1069 | <!-- *********************************************************************** --> |
| 1070 | |
| 1071 | <div class="doc_text"> |
| 1072 | |
| 1073 | <p>LLVM has several different basic types of constants. This section describes |
| 1074 | them all and their syntax.</p> |
| 1075 | |
| 1076 | </div> |
| 1077 | |
| 1078 | <!-- ======================================================================= --> |
Reid Spencer | cc16dc3 | 2004-12-09 18:02:53 +0000 | [diff] [blame] | 1079 | <div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1080 | |
| 1081 | <div class="doc_text"> |
| 1082 | |
| 1083 | <dl> |
| 1084 | <dt><b>Boolean constants</b></dt> |
| 1085 | |
| 1086 | <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid |
| 1087 | constants of the <tt><a href="#t_primitive">bool</a></tt> type. |
| 1088 | </dd> |
| 1089 | |
| 1090 | <dt><b>Integer constants</b></dt> |
| 1091 | |
Reid Spencer | cc16dc3 | 2004-12-09 18:02:53 +0000 | [diff] [blame] | 1092 | <dd>Standard integers (such as '4') are constants of the <a |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1093 | href="#t_integer">integer</a> type. Negative numbers may be used with signed |
| 1094 | integer types. |
| 1095 | </dd> |
| 1096 | |
| 1097 | <dt><b>Floating point constants</b></dt> |
| 1098 | |
| 1099 | <dd>Floating point constants use standard decimal notation (e.g. 123.421), |
| 1100 | exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1101 | notation (see below). Floating point constants must have a <a |
| 1102 | href="#t_floating">floating point</a> type. </dd> |
| 1103 | |
| 1104 | <dt><b>Null pointer constants</b></dt> |
| 1105 | |
John Criswell | 9e2485c | 2004-12-10 15:51:16 +0000 | [diff] [blame] | 1106 | <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1107 | and must be of <a href="#t_pointer">pointer type</a>.</dd> |
| 1108 | |
| 1109 | </dl> |
| 1110 | |
John Criswell | 9e2485c | 2004-12-10 15:51:16 +0000 | [diff] [blame] | 1111 | <p>The one non-intuitive notation for constants is the optional hexadecimal form |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1112 | of floating point constants. For example, the form '<tt>double |
| 1113 | 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double |
| 1114 | 4.5e+15</tt>'. The only time hexadecimal floating point constants are required |
Reid Spencer | cc16dc3 | 2004-12-09 18:02:53 +0000 | [diff] [blame] | 1115 | (and the only time that they are generated by the disassembler) is when a |
| 1116 | floating point constant must be emitted but it cannot be represented as a |
| 1117 | decimal floating point number. For example, NaN's, infinities, and other |
| 1118 | special values are represented in their IEEE hexadecimal format so that |
| 1119 | assembly and disassembly do not cause any bits to change in the constants.</p> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1120 | |
| 1121 | </div> |
| 1122 | |
| 1123 | <!-- ======================================================================= --> |
| 1124 | <div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a> |
| 1125 | </div> |
| 1126 | |
| 1127 | <div class="doc_text"> |
Chris Lattner | d4f6b17 | 2005-03-07 22:13:59 +0000 | [diff] [blame] | 1128 | <p>Aggregate constants arise from aggregation of simple constants |
| 1129 | and smaller aggregate constants.</p> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1130 | |
| 1131 | <dl> |
| 1132 | <dt><b>Structure constants</b></dt> |
| 1133 | |
| 1134 | <dd>Structure constants are represented with notation similar to structure |
| 1135 | type definitions (a comma separated list of elements, surrounded by braces |
Chris Lattner | d4f6b17 | 2005-03-07 22:13:59 +0000 | [diff] [blame] | 1136 | (<tt>{}</tt>)). For example: "<tt>{ int 4, float 17.0, int* %G }</tt>", |
| 1137 | where "<tt>%G</tt>" is declared as "<tt>%G = external global int</tt>". Structure constants |
| 1138 | must have <a href="#t_struct">structure type</a>, and the number and |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1139 | types of elements must match those specified by the type. |
| 1140 | </dd> |
| 1141 | |
| 1142 | <dt><b>Array constants</b></dt> |
| 1143 | |
| 1144 | <dd>Array constants are represented with notation similar to array type |
| 1145 | definitions (a comma separated list of elements, surrounded by square brackets |
John Criswell | 9e2485c | 2004-12-10 15:51:16 +0000 | [diff] [blame] | 1146 | (<tt>[]</tt>)). For example: "<tt>[ int 42, int 11, int 74 ]</tt>". Array |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1147 | constants must have <a href="#t_array">array type</a>, and the number and |
| 1148 | types of elements must match those specified by the type. |
| 1149 | </dd> |
| 1150 | |
| 1151 | <dt><b>Packed constants</b></dt> |
| 1152 | |
| 1153 | <dd>Packed constants are represented with notation similar to packed type |
| 1154 | definitions (a comma separated list of elements, surrounded by |
John Criswell | 9e2485c | 2004-12-10 15:51:16 +0000 | [diff] [blame] | 1155 | less-than/greater-than's (<tt><></tt>)). For example: "<tt>< int 42, |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1156 | int 11, int 74, int 100 ></tt>". Packed constants must have <a |
| 1157 | href="#t_packed">packed type</a>, and the number and types of elements must |
| 1158 | match those specified by the type. |
| 1159 | </dd> |
| 1160 | |
| 1161 | <dt><b>Zero initialization</b></dt> |
| 1162 | |
| 1163 | <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a |
| 1164 | value to zero of <em>any</em> type, including scalar and aggregate types. |
| 1165 | This is often used to avoid having to print large zero initializers (e.g. for |
John Criswell | 0ec250c | 2005-10-24 16:17:18 +0000 | [diff] [blame] | 1166 | large arrays) and is always exactly equivalent to using explicit zero |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1167 | initializers. |
| 1168 | </dd> |
| 1169 | </dl> |
| 1170 | |
| 1171 | </div> |
| 1172 | |
| 1173 | <!-- ======================================================================= --> |
| 1174 | <div class="doc_subsection"> |
| 1175 | <a name="globalconstants">Global Variable and Function Addresses</a> |
| 1176 | </div> |
| 1177 | |
| 1178 | <div class="doc_text"> |
| 1179 | |
| 1180 | <p>The addresses of <a href="#globalvars">global variables</a> and <a |
| 1181 | href="#functionstructure">functions</a> are always implicitly valid (link-time) |
John Criswell | 9e2485c | 2004-12-10 15:51:16 +0000 | [diff] [blame] | 1182 | constants. These constants are explicitly referenced when the <a |
| 1183 | href="#identifiers">identifier for the global</a> is used and always have <a |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1184 | href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM |
| 1185 | file:</p> |
| 1186 | |
| 1187 | <pre> |
| 1188 | %X = global int 17 |
| 1189 | %Y = global int 42 |
| 1190 | %Z = global [2 x int*] [ int* %X, int* %Y ] |
| 1191 | </pre> |
| 1192 | |
| 1193 | </div> |
| 1194 | |
| 1195 | <!-- ======================================================================= --> |
Reid Spencer | 2dc45b8 | 2004-12-09 18:13:12 +0000 | [diff] [blame] | 1196 | <div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1197 | <div class="doc_text"> |
Reid Spencer | 2dc45b8 | 2004-12-09 18:13:12 +0000 | [diff] [blame] | 1198 | <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 1199 | no specific value. Undefined values may be of any type and be used anywhere |
Reid Spencer | 2dc45b8 | 2004-12-09 18:13:12 +0000 | [diff] [blame] | 1200 | a constant is permitted.</p> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1201 | |
Reid Spencer | 2dc45b8 | 2004-12-09 18:13:12 +0000 | [diff] [blame] | 1202 | <p>Undefined values indicate to the compiler that the program is well defined |
| 1203 | no matter what value is used, giving the compiler more freedom to optimize. |
| 1204 | </p> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1205 | </div> |
| 1206 | |
| 1207 | <!-- ======================================================================= --> |
| 1208 | <div class="doc_subsection"><a name="constantexprs">Constant Expressions</a> |
| 1209 | </div> |
| 1210 | |
| 1211 | <div class="doc_text"> |
| 1212 | |
| 1213 | <p>Constant expressions are used to allow expressions involving other constants |
| 1214 | to be used as constants. Constant expressions may be of any <a |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 1215 | href="#t_firstclass">first class</a> type and may involve any LLVM operation |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1216 | that does not have side effects (e.g. load and call are not supported). The |
| 1217 | following is the syntax for constant expressions:</p> |
| 1218 | |
| 1219 | <dl> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 1220 | <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt> |
| 1221 | <dd>Truncate a constant to another type. The bit size of CST must be larger |
| 1222 | than the bit size of TYPE. Both types must be integral.</dd> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1223 | |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 1224 | <dt><b><tt>zext ( CST to TYPE )</tt></b></dt> |
| 1225 | <dd>Zero extend a constant to another type. The bit size of CST must be |
| 1226 | smaller or equal to the bit size of TYPE. Both types must be integral.</dd> |
| 1227 | |
| 1228 | <dt><b><tt>sext ( CST to TYPE )</tt></b></dt> |
| 1229 | <dd>Sign extend a constant to another type. The bit size of CST must be |
| 1230 | smaller or equal to the bit size of TYPE. Both types must be integral.</dd> |
| 1231 | |
| 1232 | <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt> |
| 1233 | <dd>Truncate a floating point constant to another floating point type. The |
| 1234 | size of CST must be larger than the size of TYPE. Both types must be |
| 1235 | floating point.</dd> |
| 1236 | |
| 1237 | <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt> |
| 1238 | <dd>Floating point extend a constant to another type. The size of CST must be |
| 1239 | smaller or equal to the size of TYPE. Both types must be floating point.</dd> |
| 1240 | |
| 1241 | <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt> |
| 1242 | <dd>Convert a floating point constant to the corresponding unsigned integer |
| 1243 | constant. TYPE must be an integer type. CST must be floating point. If the |
| 1244 | value won't fit in the integer type, the results are undefined.</dd> |
| 1245 | |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 1246 | <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 1247 | <dd>Convert a floating point constant to the corresponding signed integer |
| 1248 | constant. TYPE must be an integer type. CST must be floating point. If the |
| 1249 | value won't fit in the integer type, the results are undefined.</dd> |
| 1250 | |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 1251 | <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 1252 | <dd>Convert an unsigned integer constant to the corresponding floating point |
| 1253 | constant. TYPE must be floating point. CST must be of integer type. If the |
| 1254 | value won't fit in the floating point type, the results are undefined.</dd> |
| 1255 | |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 1256 | <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 1257 | <dd>Convert a signed integer constant to the corresponding floating point |
| 1258 | constant. TYPE must be floating point. CST must be of integer type. If the |
| 1259 | value won't fit in the floating point type, the results are undefined.</dd> |
| 1260 | |
Reid Spencer | 5c0ef47 | 2006-11-11 23:08:07 +0000 | [diff] [blame] | 1261 | <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt> |
| 1262 | <dd>Convert a pointer typed constant to the corresponding integer constant |
| 1263 | TYPE must be an integer type. CST must be of pointer type. The CST value is |
| 1264 | zero extended, truncated, or unchanged to make it fit in TYPE.</dd> |
| 1265 | |
| 1266 | <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt> |
| 1267 | <dd>Convert a integer constant to a pointer constant. TYPE must be a |
| 1268 | pointer type. CST must be of integer type. The CST value is zero extended, |
| 1269 | truncated, or unchanged to make it fit in a pointer size. This one is |
| 1270 | <i>really</i> dangerous!</dd> |
| 1271 | |
| 1272 | <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 1273 | <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be |
| 1274 | identical (same number of bits). The conversion is done as if the CST value |
| 1275 | was stored to memory and read back as TYPE. In other words, no bits change |
Reid Spencer | 5c0ef47 | 2006-11-11 23:08:07 +0000 | [diff] [blame] | 1276 | with this operator, just the type. This can be used for conversion of |
| 1277 | packed types to any other type, as long as they have the same bit width. For |
| 1278 | pointers it is only valid to cast to another pointer type. |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 1279 | </dd> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1280 | |
| 1281 | <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt> |
| 1282 | |
| 1283 | <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on |
| 1284 | constants. As with the <a href="#i_getelementptr">getelementptr</a> |
| 1285 | instruction, the index list may have zero or more indexes, which are required |
| 1286 | to make sense for the type of "CSTPTR".</dd> |
| 1287 | |
Robert Bocchino | 9fbe145 | 2006-01-10 19:31:34 +0000 | [diff] [blame] | 1288 | <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt> |
| 1289 | |
| 1290 | <dd>Perform the <a href="#i_select">select operation</a> on |
Reid Spencer | 01c4259 | 2006-12-04 19:23:19 +0000 | [diff] [blame] | 1291 | constants.</dd> |
| 1292 | |
| 1293 | <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt> |
| 1294 | <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd> |
| 1295 | |
| 1296 | <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt> |
| 1297 | <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd> |
Robert Bocchino | 9fbe145 | 2006-01-10 19:31:34 +0000 | [diff] [blame] | 1298 | |
| 1299 | <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt> |
| 1300 | |
| 1301 | <dd>Perform the <a href="#i_extractelement">extractelement |
| 1302 | operation</a> on constants. |
| 1303 | |
Robert Bocchino | 05ccd70 | 2006-01-15 20:48:27 +0000 | [diff] [blame] | 1304 | <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt> |
| 1305 | |
| 1306 | <dd>Perform the <a href="#i_insertelement">insertelement |
Reid Spencer | 01c4259 | 2006-12-04 19:23:19 +0000 | [diff] [blame] | 1307 | operation</a> on constants.</dd> |
Robert Bocchino | 05ccd70 | 2006-01-15 20:48:27 +0000 | [diff] [blame] | 1308 | |
Chris Lattner | c198954 | 2006-04-08 00:13:41 +0000 | [diff] [blame] | 1309 | |
| 1310 | <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt> |
| 1311 | |
| 1312 | <dd>Perform the <a href="#i_shufflevector">shufflevector |
Reid Spencer | 01c4259 | 2006-12-04 19:23:19 +0000 | [diff] [blame] | 1313 | operation</a> on constants.</dd> |
Chris Lattner | c198954 | 2006-04-08 00:13:41 +0000 | [diff] [blame] | 1314 | |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1315 | <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt> |
| 1316 | |
Reid Spencer | 2dc45b8 | 2004-12-09 18:13:12 +0000 | [diff] [blame] | 1317 | <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may |
| 1318 | be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1319 | binary</a> operations. The constraints on operands are the same as those for |
| 1320 | the corresponding instruction (e.g. no bitwise operations on floating point |
John Criswell | e4c57cc | 2005-05-12 16:52:32 +0000 | [diff] [blame] | 1321 | values are allowed).</dd> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1322 | </dl> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1323 | </div> |
Chris Lattner | 9ee5d22 | 2004-03-08 16:49:10 +0000 | [diff] [blame] | 1324 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1325 | <!-- *********************************************************************** --> |
Chris Lattner | e87d653 | 2006-01-25 23:47:57 +0000 | [diff] [blame] | 1326 | <div class="doc_section"> <a name="othervalues">Other Values</a> </div> |
| 1327 | <!-- *********************************************************************** --> |
| 1328 | |
| 1329 | <!-- ======================================================================= --> |
| 1330 | <div class="doc_subsection"> |
| 1331 | <a name="inlineasm">Inline Assembler Expressions</a> |
| 1332 | </div> |
| 1333 | |
| 1334 | <div class="doc_text"> |
| 1335 | |
| 1336 | <p> |
| 1337 | LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm"> |
| 1338 | Module-Level Inline Assembly</a>) through the use of a special value. This |
| 1339 | value represents the inline assembler as a string (containing the instructions |
| 1340 | to emit), a list of operand constraints (stored as a string), and a flag that |
| 1341 | indicates whether or not the inline asm expression has side effects. An example |
| 1342 | inline assembler expression is: |
| 1343 | </p> |
| 1344 | |
| 1345 | <pre> |
| 1346 | int(int) asm "bswap $0", "=r,r" |
| 1347 | </pre> |
| 1348 | |
| 1349 | <p> |
| 1350 | Inline assembler expressions may <b>only</b> be used as the callee operand of |
| 1351 | a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have: |
| 1352 | </p> |
| 1353 | |
| 1354 | <pre> |
| 1355 | %X = call int asm "<a href="#i_bswap">bswap</a> $0", "=r,r"(int %Y) |
| 1356 | </pre> |
| 1357 | |
| 1358 | <p> |
| 1359 | Inline asms with side effects not visible in the constraint list must be marked |
| 1360 | as having side effects. This is done through the use of the |
| 1361 | '<tt>sideeffect</tt>' keyword, like so: |
| 1362 | </p> |
| 1363 | |
| 1364 | <pre> |
| 1365 | call void asm sideeffect "eieio", ""() |
| 1366 | </pre> |
| 1367 | |
| 1368 | <p>TODO: The format of the asm and constraints string still need to be |
| 1369 | documented here. Constraints on what can be done (e.g. duplication, moving, etc |
| 1370 | need to be documented). |
| 1371 | </p> |
| 1372 | |
| 1373 | </div> |
| 1374 | |
| 1375 | <!-- *********************************************************************** --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1376 | <div class="doc_section"> <a name="instref">Instruction Reference</a> </div> |
| 1377 | <!-- *********************************************************************** --> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1378 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1379 | <div class="doc_text"> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1380 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1381 | <p>The LLVM instruction set consists of several different |
| 1382 | classifications of instructions: <a href="#terminators">terminator |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 1383 | instructions</a>, <a href="#binaryops">binary instructions</a>, |
| 1384 | <a href="#bitwiseops">bitwise binary instructions</a>, <a |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1385 | href="#memoryops">memory instructions</a>, and <a href="#otherops">other |
| 1386 | instructions</a>.</p> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1387 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1388 | </div> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1389 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1390 | <!-- ======================================================================= --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1391 | <div class="doc_subsection"> <a name="terminators">Terminator |
| 1392 | Instructions</a> </div> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1393 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1394 | <div class="doc_text"> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1395 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1396 | <p>As mentioned <a href="#functionstructure">previously</a>, every |
| 1397 | basic block in a program ends with a "Terminator" instruction, which |
| 1398 | indicates which block should be executed after the current block is |
| 1399 | finished. These terminator instructions typically yield a '<tt>void</tt>' |
| 1400 | value: they produce control flow, not values (the one exception being |
| 1401 | the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p> |
John Criswell | 9e2485c | 2004-12-10 15:51:16 +0000 | [diff] [blame] | 1402 | <p>There are six different terminator instructions: the '<a |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1403 | href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>' |
| 1404 | instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction, |
Chris Lattner | 35eca58 | 2004-10-16 18:04:13 +0000 | [diff] [blame] | 1405 | the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a |
| 1406 | href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a |
| 1407 | href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1408 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1409 | </div> |
Chris Lattner | c3f5976 | 2004-12-09 17:30:23 +0000 | [diff] [blame] | 1410 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1411 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1412 | <div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>' |
| 1413 | Instruction</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1414 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1415 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1416 | <pre> ret <type> <value> <i>; Return a value from a non-void function</i> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1417 | ret void <i>; Return from void function</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1418 | </pre> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1419 | <h5>Overview:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1420 | <p>The '<tt>ret</tt>' instruction is used to return control flow (and a |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 1421 | value) from a function back to the caller.</p> |
John Criswell | 4457dc9 | 2004-04-09 16:48:45 +0000 | [diff] [blame] | 1422 | <p>There are two forms of the '<tt>ret</tt>' instruction: one that |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1423 | returns a value and then causes control flow, and one that just causes |
| 1424 | control flow to occur.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1425 | <h5>Arguments:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1426 | <p>The '<tt>ret</tt>' instruction may return any '<a |
| 1427 | href="#t_firstclass">first class</a>' type. Notice that a function is |
| 1428 | not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>' |
| 1429 | instruction inside of the function that returns a value that does not |
| 1430 | match the return type of the function.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1431 | <h5>Semantics:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1432 | <p>When the '<tt>ret</tt>' instruction is executed, control flow |
| 1433 | returns back to the calling function's context. If the caller is a "<a |
John Criswell | fa08187 | 2004-06-25 15:16:57 +0000 | [diff] [blame] | 1434 | href="#i_call"><tt>call</tt></a>" instruction, execution continues at |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1435 | the instruction after the call. If the caller was an "<a |
| 1436 | href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues |
John Criswell | e4c57cc | 2005-05-12 16:52:32 +0000 | [diff] [blame] | 1437 | at the beginning of the "normal" destination block. If the instruction |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1438 | returns a value, that value shall set the call or invoke instruction's |
| 1439 | return value.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1440 | <h5>Example:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1441 | <pre> ret int 5 <i>; Return an integer value of 5</i> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 1442 | ret void <i>; Return from a void function</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1443 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1444 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1445 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1446 | <div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1447 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1448 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1449 | <pre> br bool <cond>, label <iftrue>, label <iffalse><br> br label <dest> <i>; Unconditional branch</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1450 | </pre> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1451 | <h5>Overview:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1452 | <p>The '<tt>br</tt>' instruction is used to cause control flow to |
| 1453 | transfer to a different basic block in the current function. There are |
| 1454 | two forms of this instruction, corresponding to a conditional branch |
| 1455 | and an unconditional branch.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1456 | <h5>Arguments:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1457 | <p>The conditional branch form of the '<tt>br</tt>' instruction takes a |
| 1458 | single '<tt>bool</tt>' value and two '<tt>label</tt>' values. The |
| 1459 | unconditional form of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' |
| 1460 | value as a target.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1461 | <h5>Semantics:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1462 | <p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>bool</tt>' |
| 1463 | argument is evaluated. If the value is <tt>true</tt>, control flows |
| 1464 | to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>, |
| 1465 | control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1466 | <h5>Example:</h5> |
Reid Spencer | 36d68e4 | 2006-11-18 21:55:45 +0000 | [diff] [blame] | 1467 | <pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq, int %a, %b<br> br bool %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1468 | href="#i_ret">ret</a> int 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> int 0<br></pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1469 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1470 | <!-- _______________________________________________________________________ --> |
Chris Lattner | c88c17b | 2004-02-24 04:54:45 +0000 | [diff] [blame] | 1471 | <div class="doc_subsubsection"> |
| 1472 | <a name="i_switch">'<tt>switch</tt>' Instruction</a> |
| 1473 | </div> |
| 1474 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1475 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1476 | <h5>Syntax:</h5> |
Chris Lattner | c88c17b | 2004-02-24 04:54:45 +0000 | [diff] [blame] | 1477 | |
| 1478 | <pre> |
| 1479 | switch <intty> <value>, label <defaultdest> [ <intty> <val>, label <dest> ... ] |
| 1480 | </pre> |
| 1481 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1482 | <h5>Overview:</h5> |
Chris Lattner | c88c17b | 2004-02-24 04:54:45 +0000 | [diff] [blame] | 1483 | |
| 1484 | <p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of |
| 1485 | several different places. It is a generalization of the '<tt>br</tt>' |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1486 | instruction, allowing a branch to occur to one of many possible |
| 1487 | destinations.</p> |
Chris Lattner | c88c17b | 2004-02-24 04:54:45 +0000 | [diff] [blame] | 1488 | |
| 1489 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1490 | <h5>Arguments:</h5> |
Chris Lattner | c88c17b | 2004-02-24 04:54:45 +0000 | [diff] [blame] | 1491 | |
| 1492 | <p>The '<tt>switch</tt>' instruction uses three parameters: an integer |
| 1493 | comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and |
| 1494 | an array of pairs of comparison value constants and '<tt>label</tt>'s. The |
| 1495 | table is not allowed to contain duplicate constant entries.</p> |
| 1496 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1497 | <h5>Semantics:</h5> |
Chris Lattner | c88c17b | 2004-02-24 04:54:45 +0000 | [diff] [blame] | 1498 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1499 | <p>The <tt>switch</tt> instruction specifies a table of values and |
| 1500 | destinations. When the '<tt>switch</tt>' instruction is executed, this |
John Criswell | 8411475 | 2004-06-25 16:05:06 +0000 | [diff] [blame] | 1501 | table is searched for the given value. If the value is found, control flow is |
| 1502 | transfered to the corresponding destination; otherwise, control flow is |
| 1503 | transfered to the default destination.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1504 | |
Chris Lattner | c88c17b | 2004-02-24 04:54:45 +0000 | [diff] [blame] | 1505 | <h5>Implementation:</h5> |
| 1506 | |
| 1507 | <p>Depending on properties of the target machine and the particular |
| 1508 | <tt>switch</tt> instruction, this instruction may be code generated in different |
John Criswell | 8411475 | 2004-06-25 16:05:06 +0000 | [diff] [blame] | 1509 | ways. For example, it could be generated as a series of chained conditional |
| 1510 | branches or with a lookup table.</p> |
Chris Lattner | c88c17b | 2004-02-24 04:54:45 +0000 | [diff] [blame] | 1511 | |
| 1512 | <h5>Example:</h5> |
| 1513 | |
| 1514 | <pre> |
| 1515 | <i>; Emulate a conditional br instruction</i> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 1516 | %Val = <a href="#i_zext">zext</a> bool %value to int |
Chris Lattner | c88c17b | 2004-02-24 04:54:45 +0000 | [diff] [blame] | 1517 | switch int %Val, label %truedest [int 0, label %falsedest ] |
| 1518 | |
| 1519 | <i>; Emulate an unconditional br instruction</i> |
| 1520 | switch uint 0, label %dest [ ] |
| 1521 | |
| 1522 | <i>; Implement a jump table:</i> |
| 1523 | switch uint %val, label %otherwise [ uint 0, label %onzero |
| 1524 | uint 1, label %onone |
| 1525 | uint 2, label %ontwo ] |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1526 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1527 | </div> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1528 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1529 | <!-- _______________________________________________________________________ --> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1530 | <div class="doc_subsubsection"> |
| 1531 | <a name="i_invoke">'<tt>invoke</tt>' Instruction</a> |
| 1532 | </div> |
| 1533 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1534 | <div class="doc_text"> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1535 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1536 | <h5>Syntax:</h5> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1537 | |
| 1538 | <pre> |
| 1539 | <result> = invoke [<a href="#callingconv">cconv</a>] <ptr to function ty> %<function ptr val>(<function args>) |
Chris Lattner | 76b8a33 | 2006-05-14 18:23:06 +0000 | [diff] [blame] | 1540 | to label <normal label> unwind label <exception label> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1541 | </pre> |
| 1542 | |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 1543 | <h5>Overview:</h5> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1544 | |
| 1545 | <p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified |
| 1546 | function, with the possibility of control flow transfer to either the |
John Criswell | e4c57cc | 2005-05-12 16:52:32 +0000 | [diff] [blame] | 1547 | '<tt>normal</tt>' label or the |
| 1548 | '<tt>exception</tt>' label. If the callee function returns with the |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1549 | "<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the |
| 1550 | "normal" label. If the callee (or any indirect callees) returns with the "<a |
John Criswell | e4c57cc | 2005-05-12 16:52:32 +0000 | [diff] [blame] | 1551 | href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and |
| 1552 | continued at the dynamically nearest "exception" label.</p> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1553 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1554 | <h5>Arguments:</h5> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1555 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1556 | <p>This instruction requires several arguments:</p> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1557 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1558 | <ol> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1559 | <li> |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 1560 | The optional "cconv" marker indicates which <a href="callingconv">calling |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1561 | convention</a> the call should use. If none is specified, the call defaults |
| 1562 | to using C calling conventions. |
| 1563 | </li> |
| 1564 | <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to |
| 1565 | function value being invoked. In most cases, this is a direct function |
| 1566 | invocation, but indirect <tt>invoke</tt>s are just as possible, branching off |
| 1567 | an arbitrary pointer to function value. |
| 1568 | </li> |
| 1569 | |
| 1570 | <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a |
| 1571 | function to be invoked. </li> |
| 1572 | |
| 1573 | <li>'<tt>function args</tt>': argument list whose types match the function |
| 1574 | signature argument types. If the function signature indicates the function |
| 1575 | accepts a variable number of arguments, the extra arguments can be |
| 1576 | specified. </li> |
| 1577 | |
| 1578 | <li>'<tt>normal label</tt>': the label reached when the called function |
| 1579 | executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li> |
| 1580 | |
| 1581 | <li>'<tt>exception label</tt>': the label reached when a callee returns with |
| 1582 | the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li> |
| 1583 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1584 | </ol> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1585 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1586 | <h5>Semantics:</h5> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1587 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1588 | <p>This instruction is designed to operate as a standard '<tt><a |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1589 | href="#i_call">call</a></tt>' instruction in most regards. The primary |
| 1590 | difference is that it establishes an association with a label, which is used by |
| 1591 | the runtime library to unwind the stack.</p> |
| 1592 | |
| 1593 | <p>This instruction is used in languages with destructors to ensure that proper |
| 1594 | cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown |
| 1595 | exception. Additionally, this is important for implementation of |
| 1596 | '<tt>catch</tt>' clauses in high-level languages that support them.</p> |
| 1597 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1598 | <h5>Example:</h5> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1599 | <pre> |
| 1600 | %retval = invoke int %Test(int 15) to label %Continue |
Chris Lattner | 76b8a33 | 2006-05-14 18:23:06 +0000 | [diff] [blame] | 1601 | unwind label %TestCleanup <i>; {int}:retval set</i> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 1602 | %retval = invoke <a href="#callingconv">coldcc</a> int %Test(int 15) to label %Continue |
Chris Lattner | 76b8a33 | 2006-05-14 18:23:06 +0000 | [diff] [blame] | 1603 | unwind label %TestCleanup <i>; {int}:retval set</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1604 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1605 | </div> |
Chris Lattner | 35eca58 | 2004-10-16 18:04:13 +0000 | [diff] [blame] | 1606 | |
| 1607 | |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 1608 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 35eca58 | 2004-10-16 18:04:13 +0000 | [diff] [blame] | 1609 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1610 | <div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>' |
| 1611 | Instruction</a> </div> |
Chris Lattner | 35eca58 | 2004-10-16 18:04:13 +0000 | [diff] [blame] | 1612 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1613 | <div class="doc_text"> |
Chris Lattner | 35eca58 | 2004-10-16 18:04:13 +0000 | [diff] [blame] | 1614 | |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 1615 | <h5>Syntax:</h5> |
Chris Lattner | 35eca58 | 2004-10-16 18:04:13 +0000 | [diff] [blame] | 1616 | <pre> |
| 1617 | unwind |
| 1618 | </pre> |
| 1619 | |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 1620 | <h5>Overview:</h5> |
Chris Lattner | 35eca58 | 2004-10-16 18:04:13 +0000 | [diff] [blame] | 1621 | |
| 1622 | <p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow |
| 1623 | at the first callee in the dynamic call stack which used an <a |
| 1624 | href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is |
| 1625 | primarily used to implement exception handling.</p> |
| 1626 | |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 1627 | <h5>Semantics:</h5> |
Chris Lattner | 35eca58 | 2004-10-16 18:04:13 +0000 | [diff] [blame] | 1628 | |
| 1629 | <p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to |
| 1630 | immediately halt. The dynamic call stack is then searched for the first <a |
| 1631 | href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found, |
| 1632 | execution continues at the "exceptional" destination block specified by the |
| 1633 | <tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the |
| 1634 | dynamic call chain, undefined behavior results.</p> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1635 | </div> |
Chris Lattner | 35eca58 | 2004-10-16 18:04:13 +0000 | [diff] [blame] | 1636 | |
| 1637 | <!-- _______________________________________________________________________ --> |
| 1638 | |
| 1639 | <div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>' |
| 1640 | Instruction</a> </div> |
| 1641 | |
| 1642 | <div class="doc_text"> |
| 1643 | |
| 1644 | <h5>Syntax:</h5> |
| 1645 | <pre> |
| 1646 | unreachable |
| 1647 | </pre> |
| 1648 | |
| 1649 | <h5>Overview:</h5> |
| 1650 | |
| 1651 | <p>The '<tt>unreachable</tt>' instruction has no defined semantics. This |
| 1652 | instruction is used to inform the optimizer that a particular portion of the |
| 1653 | code is not reachable. This can be used to indicate that the code after a |
| 1654 | no-return function cannot be reached, and other facts.</p> |
| 1655 | |
| 1656 | <h5>Semantics:</h5> |
| 1657 | |
| 1658 | <p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p> |
| 1659 | </div> |
| 1660 | |
| 1661 | |
| 1662 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1663 | <!-- ======================================================================= --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1664 | <div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1665 | <div class="doc_text"> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1666 | <p>Binary operators are used to do most of the computation in a |
| 1667 | program. They require two operands, execute an operation on them, and |
John Criswell | 9e2485c | 2004-12-10 15:51:16 +0000 | [diff] [blame] | 1668 | produce a single value. The operands might represent |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 1669 | multiple data, as is the case with the <a href="#t_packed">packed</a> data type. |
| 1670 | The result value of a binary operator is not |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1671 | necessarily the same type as its operands.</p> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1672 | <p>There are several different binary operators:</p> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1673 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1674 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1675 | <div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>' |
| 1676 | Instruction</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1677 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1678 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1679 | <pre> <result> = add <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1680 | </pre> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1681 | <h5>Overview:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1682 | <p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1683 | <h5>Arguments:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1684 | <p>The two arguments to the '<tt>add</tt>' instruction must be either <a |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 1685 | href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values. |
| 1686 | This instruction can also take <a href="#t_packed">packed</a> versions of the values. |
| 1687 | Both arguments must have identical types.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1688 | <h5>Semantics:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1689 | <p>The value produced is the integer or floating point sum of the two |
| 1690 | operands.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1691 | <h5>Example:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1692 | <pre> <result> = add int 4, %var <i>; yields {int}:result = 4 + %var</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1693 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1694 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1695 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1696 | <div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>' |
| 1697 | Instruction</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1698 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1699 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1700 | <pre> <result> = sub <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1701 | </pre> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1702 | <h5>Overview:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1703 | <p>The '<tt>sub</tt>' instruction returns the difference of its two |
| 1704 | operands.</p> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1705 | <p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>' |
| 1706 | instruction present in most other intermediate representations.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1707 | <h5>Arguments:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1708 | <p>The two arguments to the '<tt>sub</tt>' instruction must be either <a |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1709 | href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 1710 | values. |
| 1711 | This instruction can also take <a href="#t_packed">packed</a> versions of the values. |
| 1712 | Both arguments must have identical types.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1713 | <h5>Semantics:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1714 | <p>The value produced is the integer or floating point difference of |
| 1715 | the two operands.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1716 | <h5>Example:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1717 | <pre> <result> = sub int 4, %var <i>; yields {int}:result = 4 - %var</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1718 | <result> = sub int 0, %val <i>; yields {int}:result = -%var</i> |
| 1719 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1720 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1721 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1722 | <div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>' |
| 1723 | Instruction</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1724 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1725 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1726 | <pre> <result> = mul <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1727 | </pre> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1728 | <h5>Overview:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1729 | <p>The '<tt>mul</tt>' instruction returns the product of its two |
| 1730 | operands.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1731 | <h5>Arguments:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1732 | <p>The two arguments to the '<tt>mul</tt>' instruction must be either <a |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1733 | href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> |
Chris Lattner | a58561b | 2004-08-12 19:12:28 +0000 | [diff] [blame] | 1734 | values. |
| 1735 | This instruction can also take <a href="#t_packed">packed</a> versions of the values. |
| 1736 | Both arguments must have identical types.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1737 | <h5>Semantics:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1738 | <p>The value produced is the integer or floating point product of the |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1739 | two operands.</p> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1740 | <p>There is no signed vs unsigned multiplication. The appropriate |
| 1741 | action is taken based on the type of the operand.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1742 | <h5>Example:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1743 | <pre> <result> = mul int 4, %var <i>; yields {int}:result = 4 * %var</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1744 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1745 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1746 | <!-- _______________________________________________________________________ --> |
Reid Spencer | 1628cec | 2006-10-26 06:15:43 +0000 | [diff] [blame] | 1747 | <div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction |
| 1748 | </a></div> |
| 1749 | <div class="doc_text"> |
| 1750 | <h5>Syntax:</h5> |
| 1751 | <pre> <result> = udiv <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
| 1752 | </pre> |
| 1753 | <h5>Overview:</h5> |
| 1754 | <p>The '<tt>udiv</tt>' instruction returns the quotient of its two |
| 1755 | operands.</p> |
| 1756 | <h5>Arguments:</h5> |
| 1757 | <p>The two arguments to the '<tt>udiv</tt>' instruction must be |
| 1758 | <a href="#t_integer">integer</a> values. Both arguments must have identical |
| 1759 | types. This instruction can also take <a href="#t_packed">packed</a> versions |
| 1760 | of the values in which case the elements must be integers.</p> |
| 1761 | <h5>Semantics:</h5> |
| 1762 | <p>The value produced is the unsigned integer quotient of the two operands. This |
| 1763 | instruction always performs an unsigned division operation, regardless of |
| 1764 | whether the arguments are unsigned or not.</p> |
| 1765 | <h5>Example:</h5> |
| 1766 | <pre> <result> = udiv uint 4, %var <i>; yields {uint}:result = 4 / %var</i> |
| 1767 | </pre> |
| 1768 | </div> |
| 1769 | <!-- _______________________________________________________________________ --> |
| 1770 | <div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction |
| 1771 | </a> </div> |
| 1772 | <div class="doc_text"> |
| 1773 | <h5>Syntax:</h5> |
| 1774 | <pre> <result> = sdiv <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
| 1775 | </pre> |
| 1776 | <h5>Overview:</h5> |
| 1777 | <p>The '<tt>sdiv</tt>' instruction returns the quotient of its two |
| 1778 | operands.</p> |
| 1779 | <h5>Arguments:</h5> |
| 1780 | <p>The two arguments to the '<tt>sdiv</tt>' instruction must be |
| 1781 | <a href="#t_integer">integer</a> values. Both arguments must have identical |
| 1782 | types. This instruction can also take <a href="#t_packed">packed</a> versions |
| 1783 | of the values in which case the elements must be integers.</p> |
| 1784 | <h5>Semantics:</h5> |
| 1785 | <p>The value produced is the signed integer quotient of the two operands. This |
| 1786 | instruction always performs a signed division operation, regardless of whether |
| 1787 | the arguments are signed or not.</p> |
| 1788 | <h5>Example:</h5> |
| 1789 | <pre> <result> = sdiv int 4, %var <i>; yields {int}:result = 4 / %var</i> |
| 1790 | </pre> |
| 1791 | </div> |
| 1792 | <!-- _______________________________________________________________________ --> |
| 1793 | <div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>' |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1794 | Instruction</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1795 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1796 | <h5>Syntax:</h5> |
Reid Spencer | 1628cec | 2006-10-26 06:15:43 +0000 | [diff] [blame] | 1797 | <pre> <result> = fdiv <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1798 | </pre> |
| 1799 | <h5>Overview:</h5> |
Reid Spencer | 1628cec | 2006-10-26 06:15:43 +0000 | [diff] [blame] | 1800 | <p>The '<tt>fdiv</tt>' instruction returns the quotient of its two |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1801 | operands.</p> |
| 1802 | <h5>Arguments:</h5> |
Reid Spencer | 1628cec | 2006-10-26 06:15:43 +0000 | [diff] [blame] | 1803 | <p>The two arguments to the '<tt>div</tt>' instruction must be |
| 1804 | <a href="#t_floating">floating point</a> values. Both arguments must have |
| 1805 | identical types. This instruction can also take <a href="#t_packed">packed</a> |
| 1806 | versions of the values in which case the elements must be floating point.</p> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1807 | <h5>Semantics:</h5> |
Reid Spencer | 1628cec | 2006-10-26 06:15:43 +0000 | [diff] [blame] | 1808 | <p>The value produced is the floating point quotient of the two operands.</p> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1809 | <h5>Example:</h5> |
Reid Spencer | 1628cec | 2006-10-26 06:15:43 +0000 | [diff] [blame] | 1810 | <pre> <result> = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1811 | </pre> |
| 1812 | </div> |
| 1813 | <!-- _______________________________________________________________________ --> |
Reid Spencer | 0a783f7 | 2006-11-02 01:53:59 +0000 | [diff] [blame] | 1814 | <div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a> |
| 1815 | </div> |
| 1816 | <div class="doc_text"> |
| 1817 | <h5>Syntax:</h5> |
| 1818 | <pre> <result> = urem <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
| 1819 | </pre> |
| 1820 | <h5>Overview:</h5> |
| 1821 | <p>The '<tt>urem</tt>' instruction returns the remainder from the |
| 1822 | unsigned division of its two arguments.</p> |
| 1823 | <h5>Arguments:</h5> |
| 1824 | <p>The two arguments to the '<tt>urem</tt>' instruction must be |
| 1825 | <a href="#t_integer">integer</a> values. Both arguments must have identical |
| 1826 | types.</p> |
| 1827 | <h5>Semantics:</h5> |
| 1828 | <p>This instruction returns the unsigned integer <i>remainder</i> of a division. |
| 1829 | This instruction always performs an unsigned division to get the remainder, |
| 1830 | regardless of whether the arguments are unsigned or not.</p> |
| 1831 | <h5>Example:</h5> |
| 1832 | <pre> <result> = urem uint 4, %var <i>; yields {uint}:result = 4 % %var</i> |
| 1833 | </pre> |
| 1834 | |
| 1835 | </div> |
| 1836 | <!-- _______________________________________________________________________ --> |
| 1837 | <div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>' |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1838 | Instruction</a> </div> |
| 1839 | <div class="doc_text"> |
| 1840 | <h5>Syntax:</h5> |
Reid Spencer | 0a783f7 | 2006-11-02 01:53:59 +0000 | [diff] [blame] | 1841 | <pre> <result> = srem <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1842 | </pre> |
| 1843 | <h5>Overview:</h5> |
Reid Spencer | 0a783f7 | 2006-11-02 01:53:59 +0000 | [diff] [blame] | 1844 | <p>The '<tt>srem</tt>' instruction returns the remainder from the |
| 1845 | signed division of its two operands.</p> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1846 | <h5>Arguments:</h5> |
Reid Spencer | 0a783f7 | 2006-11-02 01:53:59 +0000 | [diff] [blame] | 1847 | <p>The two arguments to the '<tt>srem</tt>' instruction must be |
| 1848 | <a href="#t_integer">integer</a> values. Both arguments must have identical |
| 1849 | types.</p> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1850 | <h5>Semantics:</h5> |
Reid Spencer | 0a783f7 | 2006-11-02 01:53:59 +0000 | [diff] [blame] | 1851 | <p>This instruction returns the <i>remainder</i> of a division (where the result |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1852 | has the same sign as the divisor), not the <i>modulus</i> (where the |
| 1853 | result has the same sign as the dividend) of a value. For more |
John Criswell | 0ec250c | 2005-10-24 16:17:18 +0000 | [diff] [blame] | 1854 | information about the difference, see <a |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1855 | href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The |
| 1856 | Math Forum</a>.</p> |
| 1857 | <h5>Example:</h5> |
Reid Spencer | 0a783f7 | 2006-11-02 01:53:59 +0000 | [diff] [blame] | 1858 | <pre> <result> = srem int 4, %var <i>; yields {int}:result = 4 % %var</i> |
| 1859 | </pre> |
| 1860 | |
| 1861 | </div> |
| 1862 | <!-- _______________________________________________________________________ --> |
| 1863 | <div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>' |
| 1864 | Instruction</a> </div> |
| 1865 | <div class="doc_text"> |
| 1866 | <h5>Syntax:</h5> |
| 1867 | <pre> <result> = frem <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
| 1868 | </pre> |
| 1869 | <h5>Overview:</h5> |
| 1870 | <p>The '<tt>frem</tt>' instruction returns the remainder from the |
| 1871 | division of its two operands.</p> |
| 1872 | <h5>Arguments:</h5> |
| 1873 | <p>The two arguments to the '<tt>frem</tt>' instruction must be |
| 1874 | <a href="#t_floating">floating point</a> values. Both arguments must have |
| 1875 | identical types.</p> |
| 1876 | <h5>Semantics:</h5> |
| 1877 | <p>This instruction returns the <i>remainder</i> of a division.</p> |
| 1878 | <h5>Example:</h5> |
| 1879 | <pre> <result> = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1880 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1881 | </div> |
Robert Bocchino | 7b81c75 | 2006-02-17 21:18:08 +0000 | [diff] [blame] | 1882 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1883 | <!-- ======================================================================= --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1884 | <div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary |
| 1885 | Operations</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1886 | <div class="doc_text"> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1887 | <p>Bitwise binary operators are used to do various forms of |
| 1888 | bit-twiddling in a program. They are generally very efficient |
John Criswell | 9e2485c | 2004-12-10 15:51:16 +0000 | [diff] [blame] | 1889 | instructions and can commonly be strength reduced from other |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1890 | instructions. They require two operands, execute an operation on them, |
| 1891 | and produce a single value. The resulting value of the bitwise binary |
| 1892 | operators is always the same type as its first operand.</p> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1893 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1894 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1895 | <div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>' |
| 1896 | Instruction</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1897 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1898 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1899 | <pre> <result> = and <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1900 | </pre> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1901 | <h5>Overview:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1902 | <p>The '<tt>and</tt>' instruction returns the bitwise logical and of |
| 1903 | its two operands.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1904 | <h5>Arguments:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1905 | <p>The two arguments to the '<tt>and</tt>' instruction must be <a |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1906 | href="#t_integral">integral</a> values. Both arguments must have |
| 1907 | identical types.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1908 | <h5>Semantics:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1909 | <p>The truth table used for the '<tt>and</tt>' instruction is:</p> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1910 | <p> </p> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 1911 | <div style="align: center"> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1912 | <table border="1" cellspacing="0" cellpadding="4"> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1913 | <tbody> |
| 1914 | <tr> |
| 1915 | <td>In0</td> |
| 1916 | <td>In1</td> |
| 1917 | <td>Out</td> |
| 1918 | </tr> |
| 1919 | <tr> |
| 1920 | <td>0</td> |
| 1921 | <td>0</td> |
| 1922 | <td>0</td> |
| 1923 | </tr> |
| 1924 | <tr> |
| 1925 | <td>0</td> |
| 1926 | <td>1</td> |
| 1927 | <td>0</td> |
| 1928 | </tr> |
| 1929 | <tr> |
| 1930 | <td>1</td> |
| 1931 | <td>0</td> |
| 1932 | <td>0</td> |
| 1933 | </tr> |
| 1934 | <tr> |
| 1935 | <td>1</td> |
| 1936 | <td>1</td> |
| 1937 | <td>1</td> |
| 1938 | </tr> |
| 1939 | </tbody> |
| 1940 | </table> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 1941 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1942 | <h5>Example:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1943 | <pre> <result> = and int 4, %var <i>; yields {int}:result = 4 & %var</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1944 | <result> = and int 15, 40 <i>; yields {int}:result = 8</i> |
| 1945 | <result> = and int 4, 8 <i>; yields {int}:result = 0</i> |
| 1946 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1947 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1948 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1949 | <div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1950 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1951 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1952 | <pre> <result> = or <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1953 | </pre> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1954 | <h5>Overview:</h5> |
| 1955 | <p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive |
| 1956 | or of its two operands.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1957 | <h5>Arguments:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1958 | <p>The two arguments to the '<tt>or</tt>' instruction must be <a |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1959 | href="#t_integral">integral</a> values. Both arguments must have |
| 1960 | identical types.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1961 | <h5>Semantics:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 1962 | <p>The truth table used for the '<tt>or</tt>' instruction is:</p> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1963 | <p> </p> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 1964 | <div style="align: center"> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1965 | <table border="1" cellspacing="0" cellpadding="4"> |
| 1966 | <tbody> |
| 1967 | <tr> |
| 1968 | <td>In0</td> |
| 1969 | <td>In1</td> |
| 1970 | <td>Out</td> |
| 1971 | </tr> |
| 1972 | <tr> |
| 1973 | <td>0</td> |
| 1974 | <td>0</td> |
| 1975 | <td>0</td> |
| 1976 | </tr> |
| 1977 | <tr> |
| 1978 | <td>0</td> |
| 1979 | <td>1</td> |
| 1980 | <td>1</td> |
| 1981 | </tr> |
| 1982 | <tr> |
| 1983 | <td>1</td> |
| 1984 | <td>0</td> |
| 1985 | <td>1</td> |
| 1986 | </tr> |
| 1987 | <tr> |
| 1988 | <td>1</td> |
| 1989 | <td>1</td> |
| 1990 | <td>1</td> |
| 1991 | </tr> |
| 1992 | </tbody> |
| 1993 | </table> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 1994 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1995 | <h5>Example:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 1996 | <pre> <result> = or int 4, %var <i>; yields {int}:result = 4 | %var</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 1997 | <result> = or int 15, 40 <i>; yields {int}:result = 47</i> |
| 1998 | <result> = or int 4, 8 <i>; yields {int}:result = 12</i> |
| 1999 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2000 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2001 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2002 | <div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>' |
| 2003 | Instruction</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2004 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2005 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2006 | <pre> <result> = xor <ty> <var1>, <var2> <i>; yields {ty}:result</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2007 | </pre> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2008 | <h5>Overview:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2009 | <p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive |
| 2010 | or of its two operands. The <tt>xor</tt> is used to implement the |
| 2011 | "one's complement" operation, which is the "~" operator in C.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2012 | <h5>Arguments:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2013 | <p>The two arguments to the '<tt>xor</tt>' instruction must be <a |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2014 | href="#t_integral">integral</a> values. Both arguments must have |
| 2015 | identical types.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2016 | <h5>Semantics:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2017 | <p>The truth table used for the '<tt>xor</tt>' instruction is:</p> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2018 | <p> </p> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 2019 | <div style="align: center"> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2020 | <table border="1" cellspacing="0" cellpadding="4"> |
| 2021 | <tbody> |
| 2022 | <tr> |
| 2023 | <td>In0</td> |
| 2024 | <td>In1</td> |
| 2025 | <td>Out</td> |
| 2026 | </tr> |
| 2027 | <tr> |
| 2028 | <td>0</td> |
| 2029 | <td>0</td> |
| 2030 | <td>0</td> |
| 2031 | </tr> |
| 2032 | <tr> |
| 2033 | <td>0</td> |
| 2034 | <td>1</td> |
| 2035 | <td>1</td> |
| 2036 | </tr> |
| 2037 | <tr> |
| 2038 | <td>1</td> |
| 2039 | <td>0</td> |
| 2040 | <td>1</td> |
| 2041 | </tr> |
| 2042 | <tr> |
| 2043 | <td>1</td> |
| 2044 | <td>1</td> |
| 2045 | <td>0</td> |
| 2046 | </tr> |
| 2047 | </tbody> |
| 2048 | </table> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 2049 | </div> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2050 | <p> </p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2051 | <h5>Example:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2052 | <pre> <result> = xor int 4, %var <i>; yields {int}:result = 4 ^ %var</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2053 | <result> = xor int 15, 40 <i>; yields {int}:result = 39</i> |
| 2054 | <result> = xor int 4, 8 <i>; yields {int}:result = 12</i> |
Chris Lattner | 27f71f2 | 2003-09-03 00:41:47 +0000 | [diff] [blame] | 2055 | <result> = xor int %V, -1 <i>; yields {int}:result = ~%V</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2056 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2057 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2058 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2059 | <div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>' |
| 2060 | Instruction</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2061 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2062 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2063 | <pre> <result> = shl <ty> <var1>, ubyte <var2> <i>; yields {ty}:result</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2064 | </pre> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2065 | <h5>Overview:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2066 | <p>The '<tt>shl</tt>' instruction returns the first operand shifted to |
| 2067 | the left a specified number of bits.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2068 | <h5>Arguments:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2069 | <p>The first argument to the '<tt>shl</tt>' instruction must be an <a |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2070 | href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>' |
| 2071 | type.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2072 | <h5>Semantics:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2073 | <p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2074 | <h5>Example:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2075 | <pre> <result> = shl int 4, ubyte %var <i>; yields {int}:result = 4 << %var</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2076 | <result> = shl int 4, ubyte 2 <i>; yields {int}:result = 16</i> |
| 2077 | <result> = shl int 1, ubyte 10 <i>; yields {int}:result = 1024</i> |
| 2078 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2079 | </div> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2080 | <!-- _______________________________________________________________________ --> |
Reid Spencer | 3822ff5 | 2006-11-08 06:47:33 +0000 | [diff] [blame] | 2081 | <div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>' |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2082 | Instruction</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2083 | <div class="doc_text"> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2084 | <h5>Syntax:</h5> |
Reid Spencer | 3822ff5 | 2006-11-08 06:47:33 +0000 | [diff] [blame] | 2085 | <pre> <result> = lshr <ty> <var1>, ubyte <var2> <i>; yields {ty}:result</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2086 | </pre> |
Reid Spencer | 3822ff5 | 2006-11-08 06:47:33 +0000 | [diff] [blame] | 2087 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2088 | <h5>Overview:</h5> |
Reid Spencer | 3822ff5 | 2006-11-08 06:47:33 +0000 | [diff] [blame] | 2089 | <p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first |
| 2090 | operand shifted to the right a specified number of bits.</p> |
| 2091 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2092 | <h5>Arguments:</h5> |
Reid Spencer | 3822ff5 | 2006-11-08 06:47:33 +0000 | [diff] [blame] | 2093 | <p>The first argument to the '<tt>lshr</tt>' instruction must be an <a |
| 2094 | href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>' type.</p> |
| 2095 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2096 | <h5>Semantics:</h5> |
Reid Spencer | 3822ff5 | 2006-11-08 06:47:33 +0000 | [diff] [blame] | 2097 | <p>This instruction always performs a logical shift right operation, regardless |
| 2098 | of whether the arguments are unsigned or not. The <tt>var2</tt> most significant |
| 2099 | bits will be filled with zero bits after the shift.</p> |
| 2100 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2101 | <h5>Example:</h5> |
Reid Spencer | 3822ff5 | 2006-11-08 06:47:33 +0000 | [diff] [blame] | 2102 | <pre> |
| 2103 | <result> = lshr uint 4, ubyte 1 <i>; yields {uint}:result = 2</i> |
| 2104 | <result> = lshr int 4, ubyte 2 <i>; yields {uint}:result = 1</i> |
| 2105 | <result> = lshr sbyte 4, ubyte 3 <i>; yields {sbyte}:result = 0</i> |
| 2106 | <result> = lshr sbyte -2, ubyte 1 <i>; yields {sbyte}:result = 0x7FFFFFFF </i> |
| 2107 | </pre> |
| 2108 | </div> |
| 2109 | |
| 2110 | <!-- ======================================================================= --> |
| 2111 | <div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>' |
| 2112 | Instruction</a> </div> |
| 2113 | <div class="doc_text"> |
| 2114 | |
| 2115 | <h5>Syntax:</h5> |
| 2116 | <pre> <result> = ashr <ty> <var1>, ubyte <var2> <i>; yields {ty}:result</i> |
| 2117 | </pre> |
| 2118 | |
| 2119 | <h5>Overview:</h5> |
| 2120 | <p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first |
| 2121 | operand shifted to the right a specified number of bits.</p> |
| 2122 | |
| 2123 | <h5>Arguments:</h5> |
| 2124 | <p>The first argument to the '<tt>ashr</tt>' instruction must be an |
| 2125 | <a href="#t_integer">integer</a> type. The second argument must be an |
| 2126 | '<tt>ubyte</tt>' type.</p> |
| 2127 | |
| 2128 | <h5>Semantics:</h5> |
| 2129 | <p>This instruction always performs an arithmetic shift right operation, |
| 2130 | regardless of whether the arguments are signed or not. The <tt>var2</tt> most |
| 2131 | significant bits will be filled with the sign bit of <tt>var1</tt>.</p> |
| 2132 | |
| 2133 | <h5>Example:</h5> |
| 2134 | <pre> |
| 2135 | <result> = ashr uint 4, ubyte 1 <i>; yields {uint}:result = 2</i> |
| 2136 | <result> = ashr int 4, ubyte 2 <i>; yields {int}:result = 1</i> |
| 2137 | <result> = ashr ubyte 4, ubyte 3 <i>; yields {ubyte}:result = 0</i> |
| 2138 | <result> = ashr sbyte -2, ubyte 1 <i>; yields {sbyte}:result = -1</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2139 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2140 | </div> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2141 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2142 | <!-- ======================================================================= --> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2143 | <div class="doc_subsection"> |
Chris Lattner | 3df241e | 2006-04-08 23:07:04 +0000 | [diff] [blame] | 2144 | <a name="vectorops">Vector Operations</a> |
| 2145 | </div> |
| 2146 | |
| 2147 | <div class="doc_text"> |
| 2148 | |
| 2149 | <p>LLVM supports several instructions to represent vector operations in a |
| 2150 | target-independent manner. This instructions cover the element-access and |
| 2151 | vector-specific operations needed to process vectors effectively. While LLVM |
| 2152 | does directly support these vector operations, many sophisticated algorithms |
| 2153 | will want to use target-specific intrinsics to take full advantage of a specific |
| 2154 | target.</p> |
| 2155 | |
| 2156 | </div> |
| 2157 | |
| 2158 | <!-- _______________________________________________________________________ --> |
| 2159 | <div class="doc_subsubsection"> |
| 2160 | <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a> |
| 2161 | </div> |
| 2162 | |
| 2163 | <div class="doc_text"> |
| 2164 | |
| 2165 | <h5>Syntax:</h5> |
| 2166 | |
| 2167 | <pre> |
| 2168 | <result> = extractelement <n x <ty>> <val>, uint <idx> <i>; yields <ty></i> |
| 2169 | </pre> |
| 2170 | |
| 2171 | <h5>Overview:</h5> |
| 2172 | |
| 2173 | <p> |
| 2174 | The '<tt>extractelement</tt>' instruction extracts a single scalar |
| 2175 | element from a packed vector at a specified index. |
| 2176 | </p> |
| 2177 | |
| 2178 | |
| 2179 | <h5>Arguments:</h5> |
| 2180 | |
| 2181 | <p> |
| 2182 | The first operand of an '<tt>extractelement</tt>' instruction is a |
| 2183 | value of <a href="#t_packed">packed</a> type. The second operand is |
| 2184 | an index indicating the position from which to extract the element. |
| 2185 | The index may be a variable.</p> |
| 2186 | |
| 2187 | <h5>Semantics:</h5> |
| 2188 | |
| 2189 | <p> |
| 2190 | The result is a scalar of the same type as the element type of |
| 2191 | <tt>val</tt>. Its value is the value at position <tt>idx</tt> of |
| 2192 | <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the |
| 2193 | results are undefined. |
| 2194 | </p> |
| 2195 | |
| 2196 | <h5>Example:</h5> |
| 2197 | |
| 2198 | <pre> |
| 2199 | %result = extractelement <4 x int> %vec, uint 0 <i>; yields int</i> |
| 2200 | </pre> |
| 2201 | </div> |
| 2202 | |
| 2203 | |
| 2204 | <!-- _______________________________________________________________________ --> |
| 2205 | <div class="doc_subsubsection"> |
| 2206 | <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a> |
| 2207 | </div> |
| 2208 | |
| 2209 | <div class="doc_text"> |
| 2210 | |
| 2211 | <h5>Syntax:</h5> |
| 2212 | |
| 2213 | <pre> |
| 2214 | <result> = insertelement <n x <ty>> <val>, <ty> <elt>, uint <idx> <i>; yields <n x <ty>></i> |
| 2215 | </pre> |
| 2216 | |
| 2217 | <h5>Overview:</h5> |
| 2218 | |
| 2219 | <p> |
| 2220 | The '<tt>insertelement</tt>' instruction inserts a scalar |
| 2221 | element into a packed vector at a specified index. |
| 2222 | </p> |
| 2223 | |
| 2224 | |
| 2225 | <h5>Arguments:</h5> |
| 2226 | |
| 2227 | <p> |
| 2228 | The first operand of an '<tt>insertelement</tt>' instruction is a |
| 2229 | value of <a href="#t_packed">packed</a> type. The second operand is a |
| 2230 | scalar value whose type must equal the element type of the first |
| 2231 | operand. The third operand is an index indicating the position at |
| 2232 | which to insert the value. The index may be a variable.</p> |
| 2233 | |
| 2234 | <h5>Semantics:</h5> |
| 2235 | |
| 2236 | <p> |
| 2237 | The result is a packed vector of the same type as <tt>val</tt>. Its |
| 2238 | element values are those of <tt>val</tt> except at position |
| 2239 | <tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt> |
| 2240 | exceeds the length of <tt>val</tt>, the results are undefined. |
| 2241 | </p> |
| 2242 | |
| 2243 | <h5>Example:</h5> |
| 2244 | |
| 2245 | <pre> |
| 2246 | %result = insertelement <4 x int> %vec, int 1, uint 0 <i>; yields <4 x int></i> |
| 2247 | </pre> |
| 2248 | </div> |
| 2249 | |
| 2250 | <!-- _______________________________________________________________________ --> |
| 2251 | <div class="doc_subsubsection"> |
| 2252 | <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a> |
| 2253 | </div> |
| 2254 | |
| 2255 | <div class="doc_text"> |
| 2256 | |
| 2257 | <h5>Syntax:</h5> |
| 2258 | |
| 2259 | <pre> |
| 2260 | <result> = shufflevector <n x <ty>> <v1>, <n x <ty>> <v2>, <n x uint> <mask> <i>; yields <n x <ty>></i> |
| 2261 | </pre> |
| 2262 | |
| 2263 | <h5>Overview:</h5> |
| 2264 | |
| 2265 | <p> |
| 2266 | The '<tt>shufflevector</tt>' instruction constructs a permutation of elements |
| 2267 | from two input vectors, returning a vector of the same type. |
| 2268 | </p> |
| 2269 | |
| 2270 | <h5>Arguments:</h5> |
| 2271 | |
| 2272 | <p> |
| 2273 | The first two operands of a '<tt>shufflevector</tt>' instruction are vectors |
| 2274 | with types that match each other and types that match the result of the |
| 2275 | instruction. The third argument is a shuffle mask, which has the same number |
| 2276 | of elements as the other vector type, but whose element type is always 'uint'. |
| 2277 | </p> |
| 2278 | |
| 2279 | <p> |
| 2280 | The shuffle mask operand is required to be a constant vector with either |
| 2281 | constant integer or undef values. |
| 2282 | </p> |
| 2283 | |
| 2284 | <h5>Semantics:</h5> |
| 2285 | |
| 2286 | <p> |
| 2287 | The elements of the two input vectors are numbered from left to right across |
| 2288 | both of the vectors. The shuffle mask operand specifies, for each element of |
| 2289 | the result vector, which element of the two input registers the result element |
| 2290 | gets. The element selector may be undef (meaning "don't care") and the second |
| 2291 | operand may be undef if performing a shuffle from only one vector. |
| 2292 | </p> |
| 2293 | |
| 2294 | <h5>Example:</h5> |
| 2295 | |
| 2296 | <pre> |
| 2297 | %result = shufflevector <4 x int> %v1, <4 x int> %v2, |
| 2298 | <4 x uint> <uint 0, uint 4, uint 1, uint 5> <i>; yields <4 x int></i> |
| 2299 | %result = shufflevector <4 x int> %v1, <4 x int> undef, |
| 2300 | <4 x uint> <uint 0, uint 1, uint 2, uint 3> <i>; yields <4 x int></i> - Identity shuffle. |
| 2301 | </pre> |
| 2302 | </div> |
| 2303 | |
Tanya Lattner | 0947429 | 2006-04-14 19:24:33 +0000 | [diff] [blame] | 2304 | |
Chris Lattner | 3df241e | 2006-04-08 23:07:04 +0000 | [diff] [blame] | 2305 | <!-- ======================================================================= --> |
| 2306 | <div class="doc_subsection"> |
Chris Lattner | 884a970 | 2006-08-15 00:45:58 +0000 | [diff] [blame] | 2307 | <a name="memoryops">Memory Access and Addressing Operations</a> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2308 | </div> |
| 2309 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2310 | <div class="doc_text"> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2311 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2312 | <p>A key design point of an SSA-based representation is how it |
| 2313 | represents memory. In LLVM, no memory locations are in SSA form, which |
| 2314 | makes things very simple. This section describes how to read, write, |
John Criswell | 9e2485c | 2004-12-10 15:51:16 +0000 | [diff] [blame] | 2315 | allocate, and free memory in LLVM.</p> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2316 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2317 | </div> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2318 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2319 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2320 | <div class="doc_subsubsection"> |
| 2321 | <a name="i_malloc">'<tt>malloc</tt>' Instruction</a> |
| 2322 | </div> |
| 2323 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2324 | <div class="doc_text"> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2325 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2326 | <h5>Syntax:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2327 | |
| 2328 | <pre> |
| 2329 | <result> = malloc <type>[, uint <NumElements>][, align <alignment>] <i>; yields {type*}:result</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2330 | </pre> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2331 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2332 | <h5>Overview:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2333 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2334 | <p>The '<tt>malloc</tt>' instruction allocates memory from the system |
| 2335 | heap and returns a pointer to it.</p> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2336 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2337 | <h5>Arguments:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2338 | |
| 2339 | <p>The '<tt>malloc</tt>' instruction allocates |
| 2340 | <tt>sizeof(<type>)*NumElements</tt> |
John Criswell | 6e4ca61 | 2004-02-24 16:13:56 +0000 | [diff] [blame] | 2341 | bytes of memory from the operating system and returns a pointer of the |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2342 | appropriate type to the program. If "NumElements" is specified, it is the |
| 2343 | number of elements allocated. If an alignment is specified, the value result |
| 2344 | of the allocation is guaranteed to be aligned to at least that boundary. If |
| 2345 | not specified, or if zero, the target can choose to align the allocation on any |
| 2346 | convenient boundary.</p> |
| 2347 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2348 | <p>'<tt>type</tt>' must be a sized type.</p> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2349 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2350 | <h5>Semantics:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2351 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2352 | <p>Memory is allocated using the system "<tt>malloc</tt>" function, and |
| 2353 | a pointer is returned.</p> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2354 | |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2355 | <h5>Example:</h5> |
| 2356 | |
| 2357 | <pre> |
| 2358 | %array = malloc [4 x ubyte ] <i>; yields {[%4 x ubyte]*}:array</i> |
| 2359 | |
| 2360 | %size = <a href="#i_add">add</a> uint 2, 2 <i>; yields {uint}:size = uint 4</i> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 2361 | %array1 = malloc ubyte, uint 4 <i>; yields {ubyte*}:array1</i> |
| 2362 | %array2 = malloc [12 x ubyte], uint %size <i>; yields {[12 x ubyte]*}:array2</i> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2363 | %array3 = malloc int, uint 4, align 1024 <i>; yields {int*}:array3</i> |
| 2364 | %array4 = malloc int, align 1024 <i>; yields {int*}:array4</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2365 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2366 | </div> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2367 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2368 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2369 | <div class="doc_subsubsection"> |
| 2370 | <a name="i_free">'<tt>free</tt>' Instruction</a> |
| 2371 | </div> |
| 2372 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2373 | <div class="doc_text"> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2374 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2375 | <h5>Syntax:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2376 | |
| 2377 | <pre> |
| 2378 | free <type> <value> <i>; yields {void}</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2379 | </pre> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2380 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2381 | <h5>Overview:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2382 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2383 | <p>The '<tt>free</tt>' instruction returns memory back to the unused |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 2384 | memory heap to be reallocated in the future.</p> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2385 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2386 | <h5>Arguments:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2387 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2388 | <p>'<tt>value</tt>' shall be a pointer value that points to a value |
| 2389 | that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>' |
| 2390 | instruction.</p> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2391 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2392 | <h5>Semantics:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2393 | |
John Criswell | 9e2485c | 2004-12-10 15:51:16 +0000 | [diff] [blame] | 2394 | <p>Access to the memory pointed to by the pointer is no longer defined |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2395 | after this instruction executes.</p> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2396 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2397 | <h5>Example:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2398 | |
| 2399 | <pre> |
| 2400 | %array = <a href="#i_malloc">malloc</a> [4 x ubyte] <i>; yields {[4 x ubyte]*}:array</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2401 | free [4 x ubyte]* %array |
| 2402 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2403 | </div> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2404 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2405 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2406 | <div class="doc_subsubsection"> |
| 2407 | <a name="i_alloca">'<tt>alloca</tt>' Instruction</a> |
| 2408 | </div> |
| 2409 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2410 | <div class="doc_text"> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2411 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2412 | <h5>Syntax:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2413 | |
| 2414 | <pre> |
| 2415 | <result> = alloca <type>[, uint <NumElements>][, align <alignment>] <i>; yields {type*}:result</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2416 | </pre> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2417 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2418 | <h5>Overview:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2419 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2420 | <p>The '<tt>alloca</tt>' instruction allocates memory on the current |
| 2421 | stack frame of the procedure that is live until the current function |
| 2422 | returns to its caller.</p> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2423 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2424 | <h5>Arguments:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2425 | |
John Criswell | 9e2485c | 2004-12-10 15:51:16 +0000 | [diff] [blame] | 2426 | <p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(<type>)*NumElements</tt> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2427 | bytes of memory on the runtime stack, returning a pointer of the |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2428 | appropriate type to the program. If "NumElements" is specified, it is the |
| 2429 | number of elements allocated. If an alignment is specified, the value result |
| 2430 | of the allocation is guaranteed to be aligned to at least that boundary. If |
| 2431 | not specified, or if zero, the target can choose to align the allocation on any |
| 2432 | convenient boundary.</p> |
| 2433 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2434 | <p>'<tt>type</tt>' may be any sized type.</p> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2435 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2436 | <h5>Semantics:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2437 | |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 2438 | <p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2439 | memory is automatically released when the function returns. The '<tt>alloca</tt>' |
| 2440 | instruction is commonly used to represent automatic variables that must |
| 2441 | have an address available. When the function returns (either with the <tt><a |
John Criswell | dae2e93 | 2005-05-12 16:55:34 +0000 | [diff] [blame] | 2442 | href="#i_ret">ret</a></tt> or <tt><a href="#i_unwind">unwind</a></tt> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2443 | instructions), the memory is reclaimed.</p> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2444 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2445 | <h5>Example:</h5> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2446 | |
| 2447 | <pre> |
| 2448 | %ptr = alloca int <i>; yields {int*}:ptr</i> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 2449 | %ptr = alloca int, uint 4 <i>; yields {int*}:ptr</i> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2450 | %ptr = alloca int, uint 4, align 1024 <i>; yields {int*}:ptr</i> |
| 2451 | %ptr = alloca int, align 1024 <i>; yields {int*}:ptr</i> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2452 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2453 | </div> |
Chris Lattner | 2cbdc45 | 2005-11-06 08:02:57 +0000 | [diff] [blame] | 2454 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2455 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2456 | <div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>' |
| 2457 | Instruction</a> </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2458 | <div class="doc_text"> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2459 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2460 | <pre> <result> = load <ty>* <pointer><br> <result> = volatile load <ty>* <pointer><br></pre> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2461 | <h5>Overview:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2462 | <p>The '<tt>load</tt>' instruction is used to read from memory.</p> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2463 | <h5>Arguments:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2464 | <p>The argument to the '<tt>load</tt>' instruction specifies the memory |
John Criswell | 0ec250c | 2005-10-24 16:17:18 +0000 | [diff] [blame] | 2465 | address from which to load. The pointer must point to a <a |
Chris Lattner | e53e508 | 2004-06-03 22:57:15 +0000 | [diff] [blame] | 2466 | href="#t_firstclass">first class</a> type. If the <tt>load</tt> is |
John Criswell | 0ec250c | 2005-10-24 16:17:18 +0000 | [diff] [blame] | 2467 | marked as <tt>volatile</tt>, then the optimizer is not allowed to modify |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2468 | the number or order of execution of this <tt>load</tt> with other |
| 2469 | volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt> |
| 2470 | instructions. </p> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2471 | <h5>Semantics:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2472 | <p>The location of memory pointed to is loaded.</p> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2473 | <h5>Examples:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2474 | <pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i> |
| 2475 | <a |
| 2476 | href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2477 | %val = load int* %ptr <i>; yields {int}:val = int 3</i> |
| 2478 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2479 | </div> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2480 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2481 | <div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>' |
| 2482 | Instruction</a> </div> |
Reid Spencer | 035ab57 | 2006-11-09 21:18:01 +0000 | [diff] [blame] | 2483 | <div class="doc_text"> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2484 | <h5>Syntax:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2485 | <pre> store <ty> <value>, <ty>* <pointer> <i>; yields {void}</i> |
Chris Lattner | f065107 | 2003-09-08 18:27:49 +0000 | [diff] [blame] | 2486 | volatile store <ty> <value>, <ty>* <pointer> <i>; yields {void}</i> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2487 | </pre> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2488 | <h5>Overview:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2489 | <p>The '<tt>store</tt>' instruction is used to write to memory.</p> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2490 | <h5>Arguments:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2491 | <p>There are two arguments to the '<tt>store</tt>' instruction: a value |
John Criswell | 0ec250c | 2005-10-24 16:17:18 +0000 | [diff] [blame] | 2492 | to store and an address in which to store it. The type of the '<tt><pointer></tt>' |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2493 | operand must be a pointer to the type of the '<tt><value></tt>' |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 2494 | operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2495 | optimizer is not allowed to modify the number or order of execution of |
| 2496 | this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a |
| 2497 | href="#i_store">store</a></tt> instructions.</p> |
| 2498 | <h5>Semantics:</h5> |
| 2499 | <p>The contents of memory are updated to contain '<tt><value></tt>' |
| 2500 | at the location specified by the '<tt><pointer></tt>' operand.</p> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2501 | <h5>Example:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2502 | <pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i> |
| 2503 | <a |
| 2504 | href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i> |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2505 | %val = load int* %ptr <i>; yields {int}:val = int 3</i> |
| 2506 | </pre> |
Reid Spencer | 47ce179 | 2006-11-09 21:15:49 +0000 | [diff] [blame] | 2507 | </div> |
| 2508 | |
Chris Lattner | 2b7d320 | 2002-05-06 03:03:22 +0000 | [diff] [blame] | 2509 | <!-- _______________________________________________________________________ --> |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2510 | <div class="doc_subsubsection"> |
| 2511 | <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a> |
| 2512 | </div> |
| 2513 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2514 | <div class="doc_text"> |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 2515 | <h5>Syntax:</h5> |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2516 | <pre> |
| 2517 | <result> = getelementptr <ty>* <ptrval>{, <ty> <idx>}* |
| 2518 | </pre> |
| 2519 | |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 2520 | <h5>Overview:</h5> |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2521 | |
| 2522 | <p> |
| 2523 | The '<tt>getelementptr</tt>' instruction is used to get the address of a |
| 2524 | subelement of an aggregate data structure.</p> |
| 2525 | |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 2526 | <h5>Arguments:</h5> |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2527 | |
Reid Spencer | 85f5b5b | 2006-12-04 21:29:24 +0000 | [diff] [blame] | 2528 | <p>This instruction takes a list of integer operands that indicate what |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2529 | elements of the aggregate object to index to. The actual types of the arguments |
| 2530 | provided depend on the type of the first pointer argument. The |
| 2531 | '<tt>getelementptr</tt>' instruction is used to index down through the type |
John Criswell | fc6b895 | 2005-05-16 16:17:45 +0000 | [diff] [blame] | 2532 | levels of a structure or to a specific index in an array. When indexing into a |
Reid Spencer | 42ddd84 | 2006-12-03 16:53:48 +0000 | [diff] [blame] | 2533 | structure, only <tt>uint</tt> integer constants are allowed. When indexing |
Reid Spencer | 85f5b5b | 2006-12-04 21:29:24 +0000 | [diff] [blame] | 2534 | into an array or pointer, only integers of 32 or 64 bits are allowed, and will |
| 2535 | be sign extended to 64-bit values.</p> |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2536 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2537 | <p>For example, let's consider a C code fragment and how it gets |
| 2538 | compiled to LLVM:</p> |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2539 | |
| 2540 | <pre> |
| 2541 | struct RT { |
| 2542 | char A; |
| 2543 | int B[10][20]; |
| 2544 | char C; |
| 2545 | }; |
| 2546 | struct ST { |
| 2547 | int X; |
| 2548 | double Y; |
| 2549 | struct RT Z; |
| 2550 | }; |
| 2551 | |
| 2552 | int *foo(struct ST *s) { |
| 2553 | return &s[1].Z.B[5][13]; |
| 2554 | } |
| 2555 | </pre> |
| 2556 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2557 | <p>The LLVM code generated by the GCC frontend is:</p> |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2558 | |
| 2559 | <pre> |
| 2560 | %RT = type { sbyte, [10 x [20 x int]], sbyte } |
| 2561 | %ST = type { int, double, %RT } |
| 2562 | |
Brian Gaeke | 7283e7c | 2004-07-02 21:08:14 +0000 | [diff] [blame] | 2563 | implementation |
| 2564 | |
| 2565 | int* %foo(%ST* %s) { |
| 2566 | entry: |
| 2567 | %reg = getelementptr %ST* %s, int 1, uint 2, uint 1, int 5, int 13 |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2568 | ret int* %reg |
| 2569 | } |
| 2570 | </pre> |
| 2571 | |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 2572 | <h5>Semantics:</h5> |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2573 | |
| 2574 | <p>The index types specified for the '<tt>getelementptr</tt>' instruction depend |
John Criswell | c1f786c | 2005-05-13 22:25:59 +0000 | [diff] [blame] | 2575 | on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a> |
Reid Spencer | 85f5b5b | 2006-12-04 21:29:24 +0000 | [diff] [blame] | 2576 | and <a href="#t_array">array</a> types can use a 32-bit or 64-bit |
Reid Spencer | 42ddd84 | 2006-12-03 16:53:48 +0000 | [diff] [blame] | 2577 | <a href="#t_integer">integer</a> type but the value will always be sign extended |
| 2578 | to 64-bits. <a href="#t_struct">Structure</a> types, require <tt>uint</tt> |
| 2579 | <b>constants</b>.</p> |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2580 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2581 | <p>In the example above, the first index is indexing into the '<tt>%ST*</tt>' |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2582 | type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ int, double, %RT |
| 2583 | }</tt>' type, a structure. The second index indexes into the third element of |
| 2584 | the structure, yielding a '<tt>%RT</tt>' = '<tt>{ sbyte, [10 x [20 x int]], |
| 2585 | sbyte }</tt>' type, another structure. The third index indexes into the second |
| 2586 | element of the structure, yielding a '<tt>[10 x [20 x int]]</tt>' type, an |
| 2587 | array. The two dimensions of the array are subscripted into, yielding an |
John Criswell | fc6b895 | 2005-05-16 16:17:45 +0000 | [diff] [blame] | 2588 | '<tt>int</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2589 | to this element, thus computing a value of '<tt>int*</tt>' type.</p> |
| 2590 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 2591 | <p>Note that it is perfectly legal to index partially through a |
| 2592 | structure, returning a pointer to an inner element. Because of this, |
| 2593 | the LLVM code for the given testcase is equivalent to:</p> |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2594 | |
| 2595 | <pre> |
Chris Lattner | d4f6b17 | 2005-03-07 22:13:59 +0000 | [diff] [blame] | 2596 | int* %foo(%ST* %s) { |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2597 | %t1 = getelementptr %ST* %s, int 1 <i>; yields %ST*:%t1</i> |
| 2598 | %t2 = getelementptr %ST* %t1, int 0, uint 2 <i>; yields %RT*:%t2</i> |
| 2599 | %t3 = getelementptr %RT* %t2, int 0, uint 1 <i>; yields [10 x [20 x int]]*:%t3</i> |
| 2600 | %t4 = getelementptr [10 x [20 x int]]* %t3, int 0, int 5 <i>; yields [20 x int]*:%t4</i> |
| 2601 | %t5 = getelementptr [20 x int]* %t4, int 0, int 13 <i>; yields int*:%t5</i> |
| 2602 | ret int* %t5 |
| 2603 | } |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 2604 | </pre> |
Chris Lattner | e67a951 | 2005-06-24 17:22:57 +0000 | [diff] [blame] | 2605 | |
| 2606 | <p>Note that it is undefined to access an array out of bounds: array and |
| 2607 | pointer indexes must always be within the defined bounds of the array type. |
| 2608 | The one exception for this rules is zero length arrays. These arrays are |
| 2609 | defined to be accessible as variable length arrays, which requires access |
| 2610 | beyond the zero'th element.</p> |
| 2611 | |
Chris Lattner | 884a970 | 2006-08-15 00:45:58 +0000 | [diff] [blame] | 2612 | <p>The getelementptr instruction is often confusing. For some more insight |
| 2613 | into how it works, see <a href="GetElementPtr.html">the getelementptr |
| 2614 | FAQ</a>.</p> |
| 2615 | |
Chris Lattner | 7faa883 | 2002-04-14 06:13:44 +0000 | [diff] [blame] | 2616 | <h5>Example:</h5> |
Chris Lattner | e67a951 | 2005-06-24 17:22:57 +0000 | [diff] [blame] | 2617 | |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2618 | <pre> |
| 2619 | <i>; yields [12 x ubyte]*:aptr</i> |
| 2620 | %aptr = getelementptr {int, [12 x ubyte]}* %sptr, long 0, uint 1 |
| 2621 | </pre> |
Chris Lattner | f74d5c7 | 2004-04-05 01:30:49 +0000 | [diff] [blame] | 2622 | </div> |
Reid Spencer | 47ce179 | 2006-11-09 21:15:49 +0000 | [diff] [blame] | 2623 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 2624 | <!-- ======================================================================= --> |
Reid Spencer | 2fd21e6 | 2006-11-08 01:18:52 +0000 | [diff] [blame] | 2625 | <div class="doc_subsection"> <a name="convertops">Conversion Operations</a> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2626 | </div> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2627 | <div class="doc_text"> |
Reid Spencer | 2fd21e6 | 2006-11-08 01:18:52 +0000 | [diff] [blame] | 2628 | <p>The instructions in this category are the conversion instructions (casting) |
| 2629 | which all take a single operand and a type. They perform various bit conversions |
| 2630 | on the operand.</p> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 2631 | </div> |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 2632 | |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 2633 | <!-- _______________________________________________________________________ --> |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 2634 | <div class="doc_subsubsection"> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2635 | <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a> |
| 2636 | </div> |
| 2637 | <div class="doc_text"> |
| 2638 | |
| 2639 | <h5>Syntax:</h5> |
| 2640 | <pre> |
| 2641 | <result> = trunc <ty> <value> to <ty2> <i>; yields ty2</i> |
| 2642 | </pre> |
| 2643 | |
| 2644 | <h5>Overview:</h5> |
| 2645 | <p> |
| 2646 | The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>. |
| 2647 | </p> |
| 2648 | |
| 2649 | <h5>Arguments:</h5> |
| 2650 | <p> |
| 2651 | The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must |
| 2652 | be an <a href="#t_integer">integer</a> type, and a type that specifies the size |
| 2653 | and type of the result, which must be an <a href="#t_integral">integral</a> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2654 | type. The bit size of <tt>value</tt> must be larger than the bit size of |
| 2655 | <tt>ty2</tt>. Equal sized types are not allowed.</p> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2656 | |
| 2657 | <h5>Semantics:</h5> |
| 2658 | <p> |
| 2659 | The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2660 | and converts the remaining bits to <tt>ty2</tt>. Since the source size must be |
| 2661 | larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>. |
| 2662 | It will always truncate bits.</p> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2663 | |
| 2664 | <h5>Example:</h5> |
| 2665 | <pre> |
| 2666 | %X = trunc int 257 to ubyte <i>; yields ubyte:1</i> |
| 2667 | %Y = trunc int 123 to bool <i>; yields bool:true</i> |
| 2668 | </pre> |
| 2669 | </div> |
| 2670 | |
| 2671 | <!-- _______________________________________________________________________ --> |
| 2672 | <div class="doc_subsubsection"> |
| 2673 | <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a> |
| 2674 | </div> |
| 2675 | <div class="doc_text"> |
| 2676 | |
| 2677 | <h5>Syntax:</h5> |
| 2678 | <pre> |
| 2679 | <result> = zext <ty> <value> to <ty2> <i>; yields ty2</i> |
| 2680 | </pre> |
| 2681 | |
| 2682 | <h5>Overview:</h5> |
| 2683 | <p>The '<tt>zext</tt>' instruction zero extends its operand to type |
| 2684 | <tt>ty2</tt>.</p> |
| 2685 | |
| 2686 | |
| 2687 | <h5>Arguments:</h5> |
| 2688 | <p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of |
| 2689 | <a href="#t_integral">integral</a> type, and a type to cast it to, which must |
| 2690 | also be of <a href="#t_integral">integral</a> type. The bit size of the |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2691 | <tt>value</tt> must be smaller than the bit size of the destination type, |
| 2692 | <tt>ty2</tt>.</p> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2693 | |
| 2694 | <h5>Semantics:</h5> |
| 2695 | <p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero |
| 2696 | bits until it reaches the size of the destination type, <tt>ty2</tt>. When the |
| 2697 | the operand and the type are the same size, no bit filling is done and the |
| 2698 | cast is considered a <i>no-op cast</i> because no bits change (only the type |
| 2699 | changes).</p> |
| 2700 | |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2701 | <p>When zero extending from bool, the result will alwasy be either 0 or 1.</p> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2702 | |
| 2703 | <h5>Example:</h5> |
| 2704 | <pre> |
| 2705 | %X = zext int 257 to ulong <i>; yields ulong:257</i> |
| 2706 | %Y = zext bool true to int <i>; yields int:1</i> |
| 2707 | </pre> |
| 2708 | </div> |
| 2709 | |
| 2710 | <!-- _______________________________________________________________________ --> |
| 2711 | <div class="doc_subsubsection"> |
| 2712 | <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a> |
| 2713 | </div> |
| 2714 | <div class="doc_text"> |
| 2715 | |
| 2716 | <h5>Syntax:</h5> |
| 2717 | <pre> |
| 2718 | <result> = sext <ty> <value> to <ty2> <i>; yields ty2</i> |
| 2719 | </pre> |
| 2720 | |
| 2721 | <h5>Overview:</h5> |
| 2722 | <p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p> |
| 2723 | |
| 2724 | <h5>Arguments:</h5> |
| 2725 | <p> |
| 2726 | The '<tt>sext</tt>' instruction takes a value to cast, which must be of |
| 2727 | <a href="#t_integral">integral</a> type, and a type to cast it to, which must |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2728 | also be of <a href="#t_integral">integral</a> type. The bit size of the |
| 2729 | <tt>value</tt> must be smaller than the bit size of the destination type, |
| 2730 | <tt>ty2</tt>.</p> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2731 | |
| 2732 | <h5>Semantics:</h5> |
| 2733 | <p> |
| 2734 | The '<tt>sext</tt>' instruction performs a sign extension by copying the sign |
| 2735 | bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of |
| 2736 | the type <tt>ty2</tt>. When the the operand and the type are the same size, |
| 2737 | no bit filling is done and the cast is considered a <i>no-op cast</i> because |
| 2738 | no bits change (only the type changes).</p> |
| 2739 | |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2740 | <p>When sign extending from bool, the extension always results in -1 or 0.</p> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2741 | |
| 2742 | <h5>Example:</h5> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2743 | <pre> |
| 2744 | %X = sext sbyte -1 to ushort <i>; yields ushort:65535</i> |
| 2745 | %Y = sext bool true to int <i>; yields int:-1</i> |
| 2746 | </pre> |
| 2747 | </div> |
| 2748 | |
| 2749 | <!-- _______________________________________________________________________ --> |
| 2750 | <div class="doc_subsubsection"> |
Reid Spencer | 3fa91b0 | 2006-11-09 21:48:10 +0000 | [diff] [blame] | 2751 | <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a> |
| 2752 | </div> |
| 2753 | |
| 2754 | <div class="doc_text"> |
| 2755 | |
| 2756 | <h5>Syntax:</h5> |
| 2757 | |
| 2758 | <pre> |
| 2759 | <result> = fptrunc <ty> <value> to <ty2> <i>; yields ty2</i> |
| 2760 | </pre> |
| 2761 | |
| 2762 | <h5>Overview:</h5> |
| 2763 | <p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type |
| 2764 | <tt>ty2</tt>.</p> |
| 2765 | |
| 2766 | |
| 2767 | <h5>Arguments:</h5> |
| 2768 | <p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating |
| 2769 | point</a> value to cast and a <a href="#t_floating">floating point</a> type to |
| 2770 | cast it to. The size of <tt>value</tt> must be larger than the size of |
| 2771 | <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a |
| 2772 | <i>no-op cast</i>.</p> |
| 2773 | |
| 2774 | <h5>Semantics:</h5> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2775 | <p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger |
| 2776 | <a href="#t_floating">floating point</a> type to a smaller |
| 2777 | <a href="#t_floating">floating point</a> type. If the value cannot fit within |
| 2778 | the destination type, <tt>ty2</tt>, then the results are undefined.</p> |
Reid Spencer | 3fa91b0 | 2006-11-09 21:48:10 +0000 | [diff] [blame] | 2779 | |
| 2780 | <h5>Example:</h5> |
| 2781 | <pre> |
| 2782 | %X = fptrunc double 123.0 to float <i>; yields float:123.0</i> |
| 2783 | %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i> |
| 2784 | </pre> |
| 2785 | </div> |
| 2786 | |
| 2787 | <!-- _______________________________________________________________________ --> |
| 2788 | <div class="doc_subsubsection"> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2789 | <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a> |
| 2790 | </div> |
| 2791 | <div class="doc_text"> |
| 2792 | |
| 2793 | <h5>Syntax:</h5> |
| 2794 | <pre> |
| 2795 | <result> = fpext <ty> <value> to <ty2> <i>; yields ty2</i> |
| 2796 | </pre> |
| 2797 | |
| 2798 | <h5>Overview:</h5> |
| 2799 | <p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger |
| 2800 | floating point value.</p> |
| 2801 | |
| 2802 | <h5>Arguments:</h5> |
| 2803 | <p>The '<tt>fpext</tt>' instruction takes a |
| 2804 | <a href="#t_floating">floating point</a> <tt>value</tt> to cast, |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2805 | and a <a href="#t_floating">floating point</a> type to cast it to. The source |
| 2806 | type must be smaller than the destination type.</p> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2807 | |
| 2808 | <h5>Semantics:</h5> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2809 | <p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller |
| 2810 | <a href="t_floating">floating point</a> type to a larger |
| 2811 | <a href="t_floating">floating point</a> type. The <tt>fpext</tt> cannot be |
| 2812 | used to make a <i>no-op cast</i> because it always changes bits. Use |
Reid Spencer | 5c0ef47 | 2006-11-11 23:08:07 +0000 | [diff] [blame] | 2813 | <tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2814 | |
| 2815 | <h5>Example:</h5> |
| 2816 | <pre> |
| 2817 | %X = fpext float 3.1415 to double <i>; yields double:3.1415</i> |
| 2818 | %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i> |
| 2819 | </pre> |
| 2820 | </div> |
| 2821 | |
| 2822 | <!-- _______________________________________________________________________ --> |
| 2823 | <div class="doc_subsubsection"> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2824 | <a name="i_fp2uint">'<tt>fptoui .. to</tt>' Instruction</a> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2825 | </div> |
| 2826 | <div class="doc_text"> |
| 2827 | |
| 2828 | <h5>Syntax:</h5> |
| 2829 | <pre> |
| 2830 | <result> = fp2uint <ty> <value> to <ty2> <i>; yields ty2</i> |
| 2831 | </pre> |
| 2832 | |
| 2833 | <h5>Overview:</h5> |
| 2834 | <p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its |
| 2835 | unsigned integer equivalent of type <tt>ty2</tt>. |
| 2836 | </p> |
| 2837 | |
| 2838 | <h5>Arguments:</h5> |
| 2839 | <p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a |
| 2840 | <a href="#t_floating">floating point</a> value, and a type to cast it to, which |
| 2841 | must be an <a href="#t_integral">integral</a> type.</p> |
| 2842 | |
| 2843 | <h5>Semantics:</h5> |
| 2844 | <p> The '<tt>fp2uint</tt>' instruction converts its |
| 2845 | <a href="#t_floating">floating point</a> operand into the nearest (rounding |
| 2846 | towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>, |
| 2847 | the results are undefined.</p> |
| 2848 | |
| 2849 | <p>When converting to bool, the conversion is done as a comparison against |
| 2850 | zero. If the <tt>value</tt> was zero, the bool result will be <tt>false</tt>. |
| 2851 | If the <tt>value</tt> was non-zero, the bool result will be <tt>true</tt>.</p> |
| 2852 | |
| 2853 | <h5>Example:</h5> |
| 2854 | <pre> |
| 2855 | %X = fp2uint double 123.0 to int <i>; yields int:123</i> |
| 2856 | %Y = fp2uint float 1.0E+300 to bool <i>; yields bool:true</i> |
| 2857 | %X = fp2uint float 1.04E+17 to ubyte <i>; yields undefined:1</i> |
| 2858 | </pre> |
| 2859 | </div> |
| 2860 | |
| 2861 | <!-- _______________________________________________________________________ --> |
| 2862 | <div class="doc_subsubsection"> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2863 | <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2864 | </div> |
| 2865 | <div class="doc_text"> |
| 2866 | |
| 2867 | <h5>Syntax:</h5> |
| 2868 | <pre> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2869 | <result> = fptosi <ty> <value> to <ty2> <i>; yields ty2</i> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2870 | </pre> |
| 2871 | |
| 2872 | <h5>Overview:</h5> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2873 | <p>The '<tt>fptosi</tt>' instruction converts |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2874 | <a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>. |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 2875 | </p> |
| 2876 | |
| 2877 | |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 2878 | <h5>Arguments:</h5> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2879 | <p> The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2880 | <a href="#t_floating">floating point</a> value, and a type to cast it to, which |
| 2881 | must also be an <a href="#t_integral">integral</a> type.</p> |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 2882 | |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 2883 | <h5>Semantics:</h5> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2884 | <p>The '<tt>fptosi</tt>' instruction converts its |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2885 | <a href="#t_floating">floating point</a> operand into the nearest (rounding |
| 2886 | towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>, |
| 2887 | the results are undefined.</p> |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 2888 | |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2889 | <p>When converting to bool, the conversion is done as a comparison against |
| 2890 | zero. If the <tt>value</tt> was zero, the bool result will be <tt>false</tt>. |
| 2891 | If the <tt>value</tt> was non-zero, the bool result will be <tt>true</tt>.</p> |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 2892 | |
Chris Lattner | 33ba0d9 | 2001-07-09 00:26:23 +0000 | [diff] [blame] | 2893 | <h5>Example:</h5> |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 2894 | <pre> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2895 | %X = fptosi double -123.0 to int <i>; yields int:-123</i> |
| 2896 | %Y = fptosi float 1.0E-247 to bool <i>; yields bool:true</i> |
| 2897 | %X = fptosi float 1.04E+17 to sbyte <i>; yields undefined:1</i> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2898 | </pre> |
| 2899 | </div> |
| 2900 | |
| 2901 | <!-- _______________________________________________________________________ --> |
| 2902 | <div class="doc_subsubsection"> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2903 | <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2904 | </div> |
| 2905 | <div class="doc_text"> |
| 2906 | |
| 2907 | <h5>Syntax:</h5> |
| 2908 | <pre> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2909 | <result> = uitofp <ty> <value> to <ty2> <i>; yields ty2</i> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2910 | </pre> |
| 2911 | |
| 2912 | <h5>Overview:</h5> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2913 | <p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2914 | integer and converts that value to the <tt>ty2</tt> type.</p> |
| 2915 | |
| 2916 | |
| 2917 | <h5>Arguments:</h5> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2918 | <p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be an |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2919 | <a href="#t_integral">integral</a> value, and a type to cast it to, which must |
| 2920 | be a <a href="#t_floating">floating point</a> type.</p> |
| 2921 | |
| 2922 | <h5>Semantics:</h5> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2923 | <p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2924 | integer quantity and converts it to the corresponding floating point value. If |
| 2925 | the value cannot fit in the floating point value, the results are undefined.</p> |
| 2926 | |
| 2927 | |
| 2928 | <h5>Example:</h5> |
| 2929 | <pre> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2930 | %X = uitofp int 257 to float <i>; yields float:257.0</i> |
| 2931 | %Y = uitofp sbyte -1 to double <i>; yields double:255.0</i> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2932 | </pre> |
| 2933 | </div> |
| 2934 | |
| 2935 | <!-- _______________________________________________________________________ --> |
| 2936 | <div class="doc_subsubsection"> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2937 | <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2938 | </div> |
| 2939 | <div class="doc_text"> |
| 2940 | |
| 2941 | <h5>Syntax:</h5> |
| 2942 | <pre> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2943 | <result> = sitofp <ty> <value> to <ty2> <i>; yields ty2</i> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2944 | </pre> |
| 2945 | |
| 2946 | <h5>Overview:</h5> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2947 | <p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2948 | integer and converts that value to the <tt>ty2</tt> type.</p> |
| 2949 | |
| 2950 | <h5>Arguments:</h5> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2951 | <p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be an |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2952 | <a href="#t_integral">integral</a> value, and a type to cast it to, which must be |
| 2953 | a <a href="#t_floating">floating point</a> type.</p> |
| 2954 | |
| 2955 | <h5>Semantics:</h5> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2956 | <p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2957 | integer quantity and converts it to the corresponding floating point value. If |
| 2958 | the value cannot fit in the floating point value, the results are undefined.</p> |
| 2959 | |
| 2960 | <h5>Example:</h5> |
| 2961 | <pre> |
Reid Spencer | d444879 | 2006-11-09 23:03:26 +0000 | [diff] [blame] | 2962 | %X = sitofp int 257 to float <i>; yields float:257.0</i> |
| 2963 | %Y = sitofp sbyte -1 to double <i>; yields double:-1.0</i> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 2964 | </pre> |
| 2965 | </div> |
| 2966 | |
| 2967 | <!-- _______________________________________________________________________ --> |
| 2968 | <div class="doc_subsubsection"> |
Reid Spencer | 7267925 | 2006-11-11 21:00:47 +0000 | [diff] [blame] | 2969 | <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a> |
| 2970 | </div> |
| 2971 | <div class="doc_text"> |
| 2972 | |
| 2973 | <h5>Syntax:</h5> |
| 2974 | <pre> |
| 2975 | <result> = ptrtoint <ty> <value> to <ty2> <i>; yields ty2</i> |
| 2976 | </pre> |
| 2977 | |
| 2978 | <h5>Overview:</h5> |
| 2979 | <p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to |
| 2980 | the integer type <tt>ty2</tt>.</p> |
| 2981 | |
| 2982 | <h5>Arguments:</h5> |
| 2983 | <p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which |
| 2984 | must be a <a href="t_pointer">pointer</a> value, and a type to cast it to |
| 2985 | <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type. |
| 2986 | |
| 2987 | <h5>Semantics:</h5> |
| 2988 | <p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type |
| 2989 | <tt>ty2</tt> by interpreting the pointer value as an integer and either |
| 2990 | truncating or zero extending that value to the size of the integer type. If |
| 2991 | <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If |
| 2992 | <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they |
| 2993 | are the same size, then nothing is done (<i>no-op cast</i>).</p> |
| 2994 | |
| 2995 | <h5>Example:</h5> |
| 2996 | <pre> |
| 2997 | %X = ptrtoint int* %X to sbyte <i>; yields truncation on 32-bit</i> |
| 2998 | %Y = ptrtoint int* %x to ulong <i>; yields zero extend on 32-bit</i> |
| 2999 | </pre> |
| 3000 | </div> |
| 3001 | |
| 3002 | <!-- _______________________________________________________________________ --> |
| 3003 | <div class="doc_subsubsection"> |
| 3004 | <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a> |
| 3005 | </div> |
| 3006 | <div class="doc_text"> |
| 3007 | |
| 3008 | <h5>Syntax:</h5> |
| 3009 | <pre> |
| 3010 | <result> = inttoptr <ty> <value> to <ty2> <i>; yields ty2</i> |
| 3011 | </pre> |
| 3012 | |
| 3013 | <h5>Overview:</h5> |
| 3014 | <p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to |
| 3015 | a pointer type, <tt>ty2</tt>.</p> |
| 3016 | |
| 3017 | <h5>Arguments:</h5> |
| 3018 | <p>The '<tt>inttoptr</tt>' instruction takes an <a href="i_integer">integer</a> |
| 3019 | value to cast, and a type to cast it to, which must be a |
| 3020 | <a href="#t_pointer">pointer</a> type. </tt> |
| 3021 | |
| 3022 | <h5>Semantics:</h5> |
| 3023 | <p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type |
| 3024 | <tt>ty2</tt> by applying either a zero extension or a truncation depending on |
| 3025 | the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the |
| 3026 | size of a pointer then a truncation is done. If <tt>value</tt> is smaller than |
| 3027 | the size of a pointer then a zero extension is done. If they are the same size, |
| 3028 | nothing is done (<i>no-op cast</i>).</p> |
| 3029 | |
| 3030 | <h5>Example:</h5> |
| 3031 | <pre> |
| 3032 | %X = inttoptr int 255 to int* <i>; yields zero extend on 64-bit</i> |
| 3033 | %X = inttoptr int 255 to int* <i>; yields no-op on 32-bit </i> |
| 3034 | %Y = inttoptr short 0 to int* <i>; yields zero extend on 32-bit</i> |
| 3035 | </pre> |
| 3036 | </div> |
| 3037 | |
| 3038 | <!-- _______________________________________________________________________ --> |
| 3039 | <div class="doc_subsubsection"> |
Reid Spencer | 5c0ef47 | 2006-11-11 23:08:07 +0000 | [diff] [blame] | 3040 | <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3041 | </div> |
| 3042 | <div class="doc_text"> |
| 3043 | |
| 3044 | <h5>Syntax:</h5> |
| 3045 | <pre> |
Reid Spencer | 5c0ef47 | 2006-11-11 23:08:07 +0000 | [diff] [blame] | 3046 | <result> = bitcast <ty> <value> to <ty2> <i>; yields ty2</i> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3047 | </pre> |
| 3048 | |
| 3049 | <h5>Overview:</h5> |
Reid Spencer | 5c0ef47 | 2006-11-11 23:08:07 +0000 | [diff] [blame] | 3050 | <p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3051 | <tt>ty2</tt> without changing any bits.</p> |
| 3052 | |
| 3053 | <h5>Arguments:</h5> |
Reid Spencer | 5c0ef47 | 2006-11-11 23:08:07 +0000 | [diff] [blame] | 3054 | <p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3055 | a first class value, and a type to cast it to, which must also be a <a |
| 3056 | href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt> |
| 3057 | and the destination type, <tt>ty2</tt>, must be identical.</p> |
| 3058 | |
| 3059 | <h5>Semantics:</h5> |
Reid Spencer | 5c0ef47 | 2006-11-11 23:08:07 +0000 | [diff] [blame] | 3060 | <p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type |
Reid Spencer | 7267925 | 2006-11-11 21:00:47 +0000 | [diff] [blame] | 3061 | <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with |
| 3062 | this conversion. The conversion is done as if the <tt>value</tt> had been |
| 3063 | stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be |
| 3064 | converted to other pointer types with this instruction. To convert pointers to |
| 3065 | other types, use the <a href="#i_inttoptr">inttoptr</a> or |
| 3066 | <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p> |
Reid Spencer | 9dee3ac | 2006-11-08 01:11:31 +0000 | [diff] [blame] | 3067 | |
| 3068 | <h5>Example:</h5> |
| 3069 | <pre> |
Reid Spencer | 5c0ef47 | 2006-11-11 23:08:07 +0000 | [diff] [blame] | 3070 | %X = bitcast ubyte 255 to sbyte <i>; yields sbyte:-1</i> |
| 3071 | %Y = bitcast uint* %x to sint* <i>; yields sint*:%x</i> |
| 3072 | %Z = bitcast <2xint> %V to long; <i>; yields long: %V</i> |
Chris Lattner | 33ba0d9 | 2001-07-09 00:26:23 +0000 | [diff] [blame] | 3073 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3074 | </div> |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 3075 | |
Reid Spencer | 2fd21e6 | 2006-11-08 01:18:52 +0000 | [diff] [blame] | 3076 | <!-- ======================================================================= --> |
| 3077 | <div class="doc_subsection"> <a name="otherops">Other Operations</a> </div> |
| 3078 | <div class="doc_text"> |
| 3079 | <p>The instructions in this category are the "miscellaneous" |
| 3080 | instructions, which defy better classification.</p> |
| 3081 | </div> |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3082 | |
| 3083 | <!-- _______________________________________________________________________ --> |
| 3084 | <div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a> |
| 3085 | </div> |
| 3086 | <div class="doc_text"> |
| 3087 | <h5>Syntax:</h5> |
| 3088 | <pre> <result> = icmp <cond> <ty> <var1>, <var2> <i>; yields {bool}:result</i> |
| 3089 | </pre> |
| 3090 | <h5>Overview:</h5> |
| 3091 | <p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison |
| 3092 | of its two integer operands.</p> |
| 3093 | <h5>Arguments:</h5> |
| 3094 | <p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is |
| 3095 | the condition code which indicates the kind of comparison to perform. It is not |
| 3096 | a value, just a keyword. The possibilities for the condition code are: |
| 3097 | <ol> |
| 3098 | <li><tt>eq</tt>: equal</li> |
| 3099 | <li><tt>ne</tt>: not equal </li> |
| 3100 | <li><tt>ugt</tt>: unsigned greater than</li> |
| 3101 | <li><tt>uge</tt>: unsigned greater or equal</li> |
| 3102 | <li><tt>ult</tt>: unsigned less than</li> |
| 3103 | <li><tt>ule</tt>: unsigned less or equal</li> |
| 3104 | <li><tt>sgt</tt>: signed greater than</li> |
| 3105 | <li><tt>sge</tt>: signed greater or equal</li> |
| 3106 | <li><tt>slt</tt>: signed less than</li> |
| 3107 | <li><tt>sle</tt>: signed less or equal</li> |
| 3108 | </ol> |
| 3109 | <p>The remaining two arguments must be of <a href="#t_integral">integral</a>, |
| 3110 | <a href="#t_pointer">pointer</a> or a <a href="#t_packed">packed</a> integral |
| 3111 | type. They must have identical types.</p> |
| 3112 | <h5>Semantics:</h5> |
| 3113 | <p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to |
| 3114 | the condition code given as <tt>cond</tt>. The comparison performed always |
| 3115 | yields a <a href="#t_bool">bool</a> result, as follows: |
| 3116 | <ol> |
| 3117 | <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal, |
| 3118 | <tt>false</tt> otherwise. No sign interpretation is necessary or performed. |
| 3119 | </li> |
| 3120 | <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal, |
| 3121 | <tt>false</tt> otherwise. No sign interpretation is necessary or performed. |
| 3122 | <li><tt>ugt</tt>: interprets the operands as unsigned values and yields |
| 3123 | <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li> |
| 3124 | <li><tt>uge</tt>: interprets the operands as unsigned values and yields |
| 3125 | <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li> |
| 3126 | <li><tt>ult</tt>: interprets the operands as unsigned values and yields |
| 3127 | <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li> |
| 3128 | <li><tt>ule</tt>: interprets the operands as unsigned values and yields |
| 3129 | <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li> |
| 3130 | <li><tt>sgt</tt>: interprets the operands as signed values and yields |
| 3131 | <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li> |
| 3132 | <li><tt>sge</tt>: interprets the operands as signed values and yields |
| 3133 | <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li> |
| 3134 | <li><tt>slt</tt>: interprets the operands as signed values and yields |
| 3135 | <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li> |
| 3136 | <li><tt>sle</tt>: interprets the operands as signed values and yields |
| 3137 | <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li> |
| 3138 | </li> |
| 3139 | </ol> |
| 3140 | <p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer |
| 3141 | values are treated as integers and then compared.</p> |
| 3142 | <p>If the operands are <a href="#t_packed">packed</a> typed, the elements of |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3143 | the vector are compared in turn and the predicate must hold for all |
| 3144 | elements.</p> |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3145 | |
| 3146 | <h5>Example:</h5> |
| 3147 | <pre> <result> = icmp eq int 4, 5 <i>; yields: result=false</i> |
| 3148 | <result> = icmp ne float* %X, %X <i>; yields: result=false</i> |
| 3149 | <result> = icmp ult short 4, 5 <i>; yields: result=true</i> |
| 3150 | <result> = icmp sgt sbyte 4, 5 <i>; yields: result=false</i> |
| 3151 | <result> = icmp ule sbyte -4, 5 <i>; yields: result=false</i> |
| 3152 | <result> = icmp sge sbyte 4, 5 <i>; yields: result=false</i> |
| 3153 | </pre> |
| 3154 | </div> |
| 3155 | |
| 3156 | <!-- _______________________________________________________________________ --> |
| 3157 | <div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a> |
| 3158 | </div> |
| 3159 | <div class="doc_text"> |
| 3160 | <h5>Syntax:</h5> |
| 3161 | <pre> <result> = fcmp <cond> <ty> <var1>, <var2> <i>; yields {bool}:result</i> |
| 3162 | </pre> |
| 3163 | <h5>Overview:</h5> |
| 3164 | <p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison |
| 3165 | of its floating point operands.</p> |
| 3166 | <h5>Arguments:</h5> |
| 3167 | <p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is |
| 3168 | the condition code which indicates the kind of comparison to perform. It is not |
| 3169 | a value, just a keyword. The possibilities for the condition code are: |
| 3170 | <ol> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3171 | <li><tt>false</tt>: no comparison, always returns false</li> |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3172 | <li><tt>oeq</tt>: ordered and equal</li> |
| 3173 | <li><tt>ogt</tt>: ordered and greater than </li> |
| 3174 | <li><tt>oge</tt>: ordered and greater than or equal</li> |
| 3175 | <li><tt>olt</tt>: ordered and less than </li> |
| 3176 | <li><tt>ole</tt>: ordered and less than or equal</li> |
| 3177 | <li><tt>one</tt>: ordered and not equal</li> |
| 3178 | <li><tt>ord</tt>: ordered (no nans)</li> |
| 3179 | <li><tt>ueq</tt>: unordered or equal</li> |
| 3180 | <li><tt>ugt</tt>: unordered or greater than </li> |
| 3181 | <li><tt>uge</tt>: unordered or greater than or equal</li> |
| 3182 | <li><tt>ult</tt>: unordered or less than </li> |
| 3183 | <li><tt>ule</tt>: unordered or less than or equal</li> |
| 3184 | <li><tt>une</tt>: unordered or not equal</li> |
| 3185 | <li><tt>uno</tt>: unordered (either nans)</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3186 | <li><tt>true</tt>: no comparison, always returns true</li> |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3187 | </ol> |
Reid Spencer | 93a4985 | 2006-12-06 07:08:07 +0000 | [diff] [blame] | 3188 | <p>In the preceding, <i>ordered</i> means that neither operand is a QNAN while |
| 3189 | <i>unordered</i> means that either operand may be a QNAN.</p> |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3190 | <p>The <tt>val1</tt> and <tt>val2</tt> arguments must be of |
| 3191 | <a href="#t_floating">floating point</a>, or a <a href="#t_packed">packed</a> |
| 3192 | floating point type. They must have identical types.</p> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3193 | <p>In the foregoing, <i>ordered</i> means that neither operand is a QNAN and |
| 3194 | <i>unordered</i> means that either operand is a QNAN.</p> |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3195 | <h5>Semantics:</h5> |
| 3196 | <p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to |
| 3197 | the condition code given as <tt>cond</tt>. The comparison performed always |
| 3198 | yields a <a href="#t_bool">bool</a> result, as follows: |
| 3199 | <ol> |
| 3200 | <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3201 | <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3202 | <tt>var1</tt> is equal to <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3203 | <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3204 | <tt>var1</tt> is greather than <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3205 | <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3206 | <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3207 | <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3208 | <tt>var1</tt> is less than <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3209 | <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3210 | <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3211 | <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3212 | <tt>var1</tt> is not equal to <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3213 | <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li> |
| 3214 | <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3215 | <tt>var1</tt> is equal to <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3216 | <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3217 | <tt>var1</tt> is greater than <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3218 | <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3219 | <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3220 | <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3221 | <tt>var1</tt> is less than <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3222 | <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3223 | <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3224 | <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3225 | <tt>var1</tt> is not equal to <tt>var2</tt>.</li> |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3226 | <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li> |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3227 | <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li> |
| 3228 | </ol> |
| 3229 | <p>If the operands are <a href="#t_packed">packed</a> typed, the elements of |
| 3230 | the vector are compared in turn and the predicate must hold for all elements. |
Reid Spencer | b7f2628 | 2006-11-19 03:00:14 +0000 | [diff] [blame] | 3231 | </p> |
Reid Spencer | f3a70a6 | 2006-11-18 21:50:54 +0000 | [diff] [blame] | 3232 | |
| 3233 | <h5>Example:</h5> |
| 3234 | <pre> <result> = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i> |
| 3235 | <result> = icmp one float 4.0, 5.0 <i>; yields: result=true</i> |
| 3236 | <result> = icmp olt float 4.0, 5.0 <i>; yields: result=true</i> |
| 3237 | <result> = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i> |
| 3238 | </pre> |
| 3239 | </div> |
| 3240 | |
Reid Spencer | 2fd21e6 | 2006-11-08 01:18:52 +0000 | [diff] [blame] | 3241 | <!-- _______________________________________________________________________ --> |
| 3242 | <div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>' |
| 3243 | Instruction</a> </div> |
| 3244 | <div class="doc_text"> |
| 3245 | <h5>Syntax:</h5> |
| 3246 | <pre> <result> = phi <ty> [ <val0>, <label0>], ...<br></pre> |
| 3247 | <h5>Overview:</h5> |
| 3248 | <p>The '<tt>phi</tt>' instruction is used to implement the φ node in |
| 3249 | the SSA graph representing the function.</p> |
| 3250 | <h5>Arguments:</h5> |
| 3251 | <p>The type of the incoming values are specified with the first type |
| 3252 | field. After this, the '<tt>phi</tt>' instruction takes a list of pairs |
| 3253 | as arguments, with one pair for each predecessor basic block of the |
| 3254 | current block. Only values of <a href="#t_firstclass">first class</a> |
| 3255 | type may be used as the value arguments to the PHI node. Only labels |
| 3256 | may be used as the label arguments.</p> |
| 3257 | <p>There must be no non-phi instructions between the start of a basic |
| 3258 | block and the PHI instructions: i.e. PHI instructions must be first in |
| 3259 | a basic block.</p> |
| 3260 | <h5>Semantics:</h5> |
| 3261 | <p>At runtime, the '<tt>phi</tt>' instruction logically takes on the |
| 3262 | value specified by the parameter, depending on which basic block we |
| 3263 | came from in the last <a href="#terminators">terminator</a> instruction.</p> |
| 3264 | <h5>Example:</h5> |
| 3265 | <pre>Loop: ; Infinite loop that counts from 0 on up...<br> %indvar = phi uint [ 0, %LoopHeader ], [ %nextindvar, %Loop ]<br> %nextindvar = add uint %indvar, 1<br> br label %Loop<br></pre> |
| 3266 | </div> |
| 3267 | |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 3268 | <!-- _______________________________________________________________________ --> |
| 3269 | <div class="doc_subsubsection"> |
| 3270 | <a name="i_select">'<tt>select</tt>' Instruction</a> |
| 3271 | </div> |
| 3272 | |
| 3273 | <div class="doc_text"> |
| 3274 | |
| 3275 | <h5>Syntax:</h5> |
| 3276 | |
| 3277 | <pre> |
| 3278 | <result> = select bool <cond>, <ty> <val1>, <ty> <val2> <i>; yields ty</i> |
| 3279 | </pre> |
| 3280 | |
| 3281 | <h5>Overview:</h5> |
| 3282 | |
| 3283 | <p> |
| 3284 | The '<tt>select</tt>' instruction is used to choose one value based on a |
| 3285 | condition, without branching. |
| 3286 | </p> |
| 3287 | |
| 3288 | |
| 3289 | <h5>Arguments:</h5> |
| 3290 | |
| 3291 | <p> |
| 3292 | The '<tt>select</tt>' instruction requires a boolean value indicating the condition, and two values of the same <a href="#t_firstclass">first class</a> type. |
| 3293 | </p> |
| 3294 | |
| 3295 | <h5>Semantics:</h5> |
| 3296 | |
| 3297 | <p> |
| 3298 | If the boolean condition evaluates to true, the instruction returns the first |
John Criswell | fc6b895 | 2005-05-16 16:17:45 +0000 | [diff] [blame] | 3299 | value argument; otherwise, it returns the second value argument. |
Chris Lattner | cc37aae | 2004-03-12 05:50:16 +0000 | [diff] [blame] | 3300 | </p> |
| 3301 | |
| 3302 | <h5>Example:</h5> |
| 3303 | |
| 3304 | <pre> |
| 3305 | %X = select bool true, ubyte 17, ubyte 42 <i>; yields ubyte:17</i> |
| 3306 | </pre> |
| 3307 | </div> |
| 3308 | |
Robert Bocchino | 05ccd70 | 2006-01-15 20:48:27 +0000 | [diff] [blame] | 3309 | |
| 3310 | <!-- _______________________________________________________________________ --> |
| 3311 | <div class="doc_subsubsection"> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3312 | <a name="i_call">'<tt>call</tt>' Instruction</a> |
| 3313 | </div> |
| 3314 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3315 | <div class="doc_text"> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3316 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 3317 | <h5>Syntax:</h5> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3318 | <pre> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 3319 | <result> = [tail] call [<a href="#callingconv">cconv</a>] <ty>* <fnptrval>(<param list>) |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3320 | </pre> |
| 3321 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 3322 | <h5>Overview:</h5> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3323 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3324 | <p>The '<tt>call</tt>' instruction represents a simple function call.</p> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3325 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 3326 | <h5>Arguments:</h5> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3327 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3328 | <p>This instruction requires several arguments:</p> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3329 | |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 3330 | <ol> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3331 | <li> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 3332 | <p>The optional "tail" marker indicates whether the callee function accesses |
| 3333 | any allocas or varargs in the caller. If the "tail" marker is present, the |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3334 | function call is eligible for tail call optimization. Note that calls may |
| 3335 | be marked "tail" even if they do not occur before a <a |
| 3336 | href="#i_ret"><tt>ret</tt></a> instruction. |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3337 | </li> |
| 3338 | <li> |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 3339 | <p>The optional "cconv" marker indicates which <a href="callingconv">calling |
| 3340 | convention</a> the call should use. If none is specified, the call defaults |
| 3341 | to using C calling conventions. |
| 3342 | </li> |
| 3343 | <li> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3344 | <p>'<tt>ty</tt>': shall be the signature of the pointer to function value |
| 3345 | being invoked. The argument types must match the types implied by this |
John Criswell | fc6b895 | 2005-05-16 16:17:45 +0000 | [diff] [blame] | 3346 | signature. This type can be omitted if the function is not varargs and |
| 3347 | if the function type does not return a pointer to a function.</p> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3348 | </li> |
| 3349 | <li> |
| 3350 | <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to |
| 3351 | be invoked. In most cases, this is a direct function invocation, but |
| 3352 | indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer |
John Criswell | fc6b895 | 2005-05-16 16:17:45 +0000 | [diff] [blame] | 3353 | to function value.</p> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3354 | </li> |
| 3355 | <li> |
| 3356 | <p>'<tt>function args</tt>': argument list whose types match the |
Reid Spencer | a7e302a | 2005-05-01 22:22:57 +0000 | [diff] [blame] | 3357 | function signature argument types. All arguments must be of |
| 3358 | <a href="#t_firstclass">first class</a> type. If the function signature |
| 3359 | indicates the function accepts a variable number of arguments, the extra |
| 3360 | arguments can be specified.</p> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3361 | </li> |
Chris Lattner | 6536cfe | 2002-05-06 22:08:29 +0000 | [diff] [blame] | 3362 | </ol> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3363 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 3364 | <h5>Semantics:</h5> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3365 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3366 | <p>The '<tt>call</tt>' instruction is used to cause control flow to |
| 3367 | transfer to a specified function, with its incoming arguments bound to |
| 3368 | the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>' |
| 3369 | instruction in the called function, control flow continues with the |
| 3370 | instruction after the function call, and the return value of the |
| 3371 | function is bound to the result argument. This is a simpler case of |
| 3372 | the <a href="#i_invoke">invoke</a> instruction.</p> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3373 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 3374 | <h5>Example:</h5> |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3375 | |
| 3376 | <pre> |
| 3377 | %retval = call int %test(int %argc) |
| 3378 | call int(sbyte*, ...) *%printf(sbyte* %msg, int 12, sbyte 42); |
| 3379 | %X = tail call int %foo() |
Chris Lattner | bad10ee | 2005-05-06 22:57:40 +0000 | [diff] [blame] | 3380 | %Y = tail call <a href="#callingconv">fastcc</a> int %foo() |
Chris Lattner | 2bff524 | 2005-05-06 05:47:36 +0000 | [diff] [blame] | 3381 | </pre> |
| 3382 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3383 | </div> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3384 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3385 | <!-- _______________________________________________________________________ --> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3386 | <div class="doc_subsubsection"> |
Chris Lattner | fb6977d | 2006-01-13 23:26:01 +0000 | [diff] [blame] | 3387 | <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3388 | </div> |
| 3389 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3390 | <div class="doc_text"> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3391 | |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 3392 | <h5>Syntax:</h5> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3393 | |
| 3394 | <pre> |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3395 | <resultval> = va_arg <va_list*> <arglist>, <argty> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3396 | </pre> |
| 3397 | |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 3398 | <h5>Overview:</h5> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3399 | |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3400 | <p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3401 | the "variable argument" area of a function call. It is used to implement the |
| 3402 | <tt>va_arg</tt> macro in C.</p> |
| 3403 | |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 3404 | <h5>Arguments:</h5> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3405 | |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3406 | <p>This instruction takes a <tt>va_list*</tt> value and the type of |
| 3407 | the argument. It returns a value of the specified argument type and |
Jeff Cohen | 25d4f7e | 2005-11-11 02:15:27 +0000 | [diff] [blame] | 3408 | increments the <tt>va_list</tt> to point to the next argument. Again, the |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3409 | actual type of <tt>va_list</tt> is target specific.</p> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3410 | |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 3411 | <h5>Semantics:</h5> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3412 | |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3413 | <p>The '<tt>va_arg</tt>' instruction loads an argument of the specified |
| 3414 | type from the specified <tt>va_list</tt> and causes the |
| 3415 | <tt>va_list</tt> to point to the next argument. For more information, |
| 3416 | see the variable argument handling <a href="#int_varargs">Intrinsic |
| 3417 | Functions</a>.</p> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3418 | |
| 3419 | <p>It is legal for this instruction to be called in a function which does not |
| 3420 | take a variable number of arguments, for example, the <tt>vfprintf</tt> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3421 | function.</p> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3422 | |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3423 | <p><tt>va_arg</tt> is an LLVM instruction instead of an <a |
John Criswell | fc6b895 | 2005-05-16 16:17:45 +0000 | [diff] [blame] | 3424 | href="#intrinsics">intrinsic function</a> because it takes a type as an |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3425 | argument.</p> |
| 3426 | |
Chris Lattner | 8d1a81d | 2003-10-18 05:51:36 +0000 | [diff] [blame] | 3427 | <h5>Example:</h5> |
Chris Lattner | e19d7a7 | 2004-09-27 21:51:25 +0000 | [diff] [blame] | 3428 | |
| 3429 | <p>See the <a href="#int_varargs">variable argument processing</a> section.</p> |
| 3430 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3431 | </div> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3432 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3433 | <!-- *********************************************************************** --> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3434 | <div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div> |
| 3435 | <!-- *********************************************************************** --> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3436 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3437 | <div class="doc_text"> |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 3438 | |
| 3439 | <p>LLVM supports the notion of an "intrinsic function". These functions have |
John Criswell | fc6b895 | 2005-05-16 16:17:45 +0000 | [diff] [blame] | 3440 | well known names and semantics and are required to follow certain |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 3441 | restrictions. Overall, these instructions represent an extension mechanism for |
| 3442 | the LLVM language that does not require changing all of the transformations in |
| 3443 | LLVM to add to the language (or the bytecode reader/writer, the parser, |
| 3444 | etc...).</p> |
| 3445 | |
John Criswell | fc6b895 | 2005-05-16 16:17:45 +0000 | [diff] [blame] | 3446 | <p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This |
| 3447 | prefix is reserved in LLVM for intrinsic names; thus, functions may not be named |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 3448 | this. Intrinsic functions must always be external functions: you cannot define |
| 3449 | the body of intrinsic functions. Intrinsic functions may only be used in call |
| 3450 | or invoke instructions: it is illegal to take the address of an intrinsic |
| 3451 | function. Additionally, because intrinsic functions are part of the LLVM |
| 3452 | language, it is required that they all be documented here if any are added.</p> |
| 3453 | |
| 3454 | |
John Criswell | fc6b895 | 2005-05-16 16:17:45 +0000 | [diff] [blame] | 3455 | <p>To learn how to add an intrinsic function, please see the <a |
Chris Lattner | 590cff3 | 2005-05-11 03:35:57 +0000 | [diff] [blame] | 3456 | href="ExtendingLLVM.html">Extending LLVM Guide</a>. |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 3457 | </p> |
| 3458 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3459 | </div> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3460 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3461 | <!-- ======================================================================= --> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3462 | <div class="doc_subsection"> |
| 3463 | <a name="int_varargs">Variable Argument Handling Intrinsics</a> |
| 3464 | </div> |
| 3465 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3466 | <div class="doc_text"> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3467 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3468 | <p>Variable argument support is defined in LLVM with the <a |
Chris Lattner | fb6977d | 2006-01-13 23:26:01 +0000 | [diff] [blame] | 3469 | href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3470 | intrinsic functions. These functions are related to the similarly |
| 3471 | named macros defined in the <tt><stdarg.h></tt> header file.</p> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3472 | |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3473 | <p>All of these functions operate on arguments that use a |
| 3474 | target-specific value type "<tt>va_list</tt>". The LLVM assembly |
| 3475 | language reference manual does not define what this type is, so all |
| 3476 | transformations should be prepared to handle intrinsics with any type |
| 3477 | used.</p> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3478 | |
Chris Lattner | 374ab30 | 2006-05-15 17:26:46 +0000 | [diff] [blame] | 3479 | <p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3480 | instruction and the variable argument handling intrinsic functions are |
| 3481 | used.</p> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3482 | |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 3483 | <pre> |
| 3484 | int %test(int %X, ...) { |
| 3485 | ; Initialize variable argument processing |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3486 | %ap = alloca sbyte* |
| 3487 | call void %<a href="#i_va_start">llvm.va_start</a>(sbyte** %ap) |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 3488 | |
| 3489 | ; Read a single integer argument |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3490 | %tmp = va_arg sbyte** %ap, int |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 3491 | |
| 3492 | ; Demonstrate usage of llvm.va_copy and llvm.va_end |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3493 | %aq = alloca sbyte* |
Andrew Lenharth | d0a4c62 | 2005-06-22 20:38:11 +0000 | [diff] [blame] | 3494 | call void %<a href="#i_va_copy">llvm.va_copy</a>(sbyte** %aq, sbyte** %ap) |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3495 | call void %<a href="#i_va_end">llvm.va_end</a>(sbyte** %aq) |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 3496 | |
| 3497 | ; Stop processing of arguments. |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3498 | call void %<a href="#i_va_end">llvm.va_end</a>(sbyte** %ap) |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 3499 | ret int %tmp |
| 3500 | } |
| 3501 | </pre> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3502 | </div> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3503 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3504 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3505 | <div class="doc_subsubsection"> |
| 3506 | <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a> |
| 3507 | </div> |
| 3508 | |
| 3509 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3510 | <div class="doc_text"> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3511 | <h5>Syntax:</h5> |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3512 | <pre> declare void %llvm.va_start(<va_list>* <arglist>)<br></pre> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3513 | <h5>Overview:</h5> |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3514 | <P>The '<tt>llvm.va_start</tt>' intrinsic initializes |
| 3515 | <tt>*<arglist></tt> for subsequent use by <tt><a |
| 3516 | href="#i_va_arg">va_arg</a></tt>.</p> |
| 3517 | |
| 3518 | <h5>Arguments:</h5> |
| 3519 | |
| 3520 | <P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p> |
| 3521 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3522 | <h5>Semantics:</h5> |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3523 | |
| 3524 | <P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt> |
| 3525 | macro available in C. In a target-dependent way, it initializes the |
| 3526 | <tt>va_list</tt> element the argument points to, so that the next call to |
| 3527 | <tt>va_arg</tt> will produce the first variable argument passed to the function. |
| 3528 | Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the |
| 3529 | last argument of the function, the compiler can figure that out.</p> |
| 3530 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3531 | </div> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3532 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3533 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3534 | <div class="doc_subsubsection"> |
| 3535 | <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a> |
| 3536 | </div> |
| 3537 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3538 | <div class="doc_text"> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3539 | <h5>Syntax:</h5> |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3540 | <pre> declare void %llvm.va_end(<va_list*> <arglist>)<br></pre> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3541 | <h5>Overview:</h5> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3542 | <p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt><arglist></tt> |
| 3543 | which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt> |
| 3544 | or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3545 | <h5>Arguments:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3546 | <p>The argument is a <tt>va_list</tt> to destroy.</p> |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3547 | <h5>Semantics:</h5> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3548 | <p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt> |
Chris Lattner | 261efe9 | 2003-11-25 01:02:51 +0000 | [diff] [blame] | 3549 | macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>. |
| 3550 | Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a |
| 3551 | href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly |
| 3552 | with calls to <tt>llvm.va_end</tt>.</p> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3553 | </div> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3554 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3555 | <!-- _______________________________________________________________________ --> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3556 | <div class="doc_subsubsection"> |
| 3557 | <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a> |
| 3558 | </div> |
| 3559 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3560 | <div class="doc_text"> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3561 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3562 | <h5>Syntax:</h5> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3563 | |
| 3564 | <pre> |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3565 | declare void %llvm.va_copy(<va_list>* <destarglist>, |
Andrew Lenharth | d0a4c62 | 2005-06-22 20:38:11 +0000 | [diff] [blame] | 3566 | <va_list>* <srcarglist>) |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3567 | </pre> |
| 3568 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3569 | <h5>Overview:</h5> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3570 | |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3571 | <p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from |
| 3572 | the source argument list to the destination argument list.</p> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3573 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3574 | <h5>Arguments:</h5> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3575 | |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3576 | <p>The first argument is a pointer to a <tt>va_list</tt> element to initialize. |
Andrew Lenharth | d0a4c62 | 2005-06-22 20:38:11 +0000 | [diff] [blame] | 3577 | The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p> |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3578 | |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3579 | |
Chris Lattner | d9ad5b3 | 2003-05-08 04:57:36 +0000 | [diff] [blame] | 3580 | <h5>Semantics:</h5> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3581 | |
Andrew Lenharth | 8bf607a | 2005-06-18 18:28:17 +0000 | [diff] [blame] | 3582 | <p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro |
| 3583 | available in C. In a target-dependent way, it copies the source |
| 3584 | <tt>va_list</tt> element into the destination list. This intrinsic is necessary |
| 3585 | because the <tt><a href="i_va_begin">llvm.va_begin</a></tt> intrinsic may be |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3586 | arbitrarily complex and require memory allocation, for example.</p> |
| 3587 | |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 3588 | </div> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 3589 | |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 3590 | <!-- ======================================================================= --> |
| 3591 | <div class="doc_subsection"> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3592 | <a name="int_gc">Accurate Garbage Collection Intrinsics</a> |
| 3593 | </div> |
| 3594 | |
| 3595 | <div class="doc_text"> |
| 3596 | |
| 3597 | <p> |
| 3598 | LLVM support for <a href="GarbageCollection.html">Accurate Garbage |
| 3599 | Collection</a> requires the implementation and generation of these intrinsics. |
| 3600 | These intrinsics allow identification of <a href="#i_gcroot">GC roots on the |
| 3601 | stack</a>, as well as garbage collector implementations that require <a |
| 3602 | href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers. |
| 3603 | Front-ends for type-safe garbage collected languages should generate these |
| 3604 | intrinsics to make use of the LLVM garbage collectors. For more details, see <a |
| 3605 | href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>. |
| 3606 | </p> |
| 3607 | </div> |
| 3608 | |
| 3609 | <!-- _______________________________________________________________________ --> |
| 3610 | <div class="doc_subsubsection"> |
| 3611 | <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a> |
| 3612 | </div> |
| 3613 | |
| 3614 | <div class="doc_text"> |
| 3615 | |
| 3616 | <h5>Syntax:</h5> |
| 3617 | |
| 3618 | <pre> |
Reid Spencer | a8d451e | 2005-04-26 20:50:44 +0000 | [diff] [blame] | 3619 | declare void %llvm.gcroot(<ty>** %ptrloc, <ty2>* %metadata) |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3620 | </pre> |
| 3621 | |
| 3622 | <h5>Overview:</h5> |
| 3623 | |
John Criswell | 9e2485c | 2004-12-10 15:51:16 +0000 | [diff] [blame] | 3624 | <p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3625 | the code generator, and allows some metadata to be associated with it.</p> |
| 3626 | |
| 3627 | <h5>Arguments:</h5> |
| 3628 | |
| 3629 | <p>The first argument specifies the address of a stack object that contains the |
| 3630 | root pointer. The second pointer (which must be either a constant or a global |
| 3631 | value address) contains the meta-data to be associated with the root.</p> |
| 3632 | |
| 3633 | <h5>Semantics:</h5> |
| 3634 | |
| 3635 | <p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc" |
| 3636 | location. At compile-time, the code generator generates information to allow |
| 3637 | the runtime to find the pointer at GC safe points. |
| 3638 | </p> |
| 3639 | |
| 3640 | </div> |
| 3641 | |
| 3642 | |
| 3643 | <!-- _______________________________________________________________________ --> |
| 3644 | <div class="doc_subsubsection"> |
| 3645 | <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a> |
| 3646 | </div> |
| 3647 | |
| 3648 | <div class="doc_text"> |
| 3649 | |
| 3650 | <h5>Syntax:</h5> |
| 3651 | |
| 3652 | <pre> |
Chris Lattner | 80626e9 | 2006-03-14 20:02:51 +0000 | [diff] [blame] | 3653 | declare sbyte* %llvm.gcread(sbyte* %ObjPtr, sbyte** %Ptr) |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3654 | </pre> |
| 3655 | |
| 3656 | <h5>Overview:</h5> |
| 3657 | |
| 3658 | <p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap |
| 3659 | locations, allowing garbage collector implementations that require read |
| 3660 | barriers.</p> |
| 3661 | |
| 3662 | <h5>Arguments:</h5> |
| 3663 | |
Chris Lattner | 80626e9 | 2006-03-14 20:02:51 +0000 | [diff] [blame] | 3664 | <p>The second argument is the address to read from, which should be an address |
| 3665 | allocated from the garbage collector. The first object is a pointer to the |
| 3666 | start of the referenced object, if needed by the language runtime (otherwise |
| 3667 | null).</p> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3668 | |
| 3669 | <h5>Semantics:</h5> |
| 3670 | |
| 3671 | <p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load |
| 3672 | instruction, but may be replaced with substantially more complex code by the |
| 3673 | garbage collector runtime, as needed.</p> |
| 3674 | |
| 3675 | </div> |
| 3676 | |
| 3677 | |
| 3678 | <!-- _______________________________________________________________________ --> |
| 3679 | <div class="doc_subsubsection"> |
| 3680 | <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a> |
| 3681 | </div> |
| 3682 | |
| 3683 | <div class="doc_text"> |
| 3684 | |
| 3685 | <h5>Syntax:</h5> |
| 3686 | |
| 3687 | <pre> |
Chris Lattner | 80626e9 | 2006-03-14 20:02:51 +0000 | [diff] [blame] | 3688 | declare void %llvm.gcwrite(sbyte* %P1, sbyte* %Obj, sbyte** %P2) |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3689 | </pre> |
| 3690 | |
| 3691 | <h5>Overview:</h5> |
| 3692 | |
| 3693 | <p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap |
| 3694 | locations, allowing garbage collector implementations that require write |
| 3695 | barriers (such as generational or reference counting collectors).</p> |
| 3696 | |
| 3697 | <h5>Arguments:</h5> |
| 3698 | |
Chris Lattner | 80626e9 | 2006-03-14 20:02:51 +0000 | [diff] [blame] | 3699 | <p>The first argument is the reference to store, the second is the start of the |
| 3700 | object to store it to, and the third is the address of the field of Obj to |
| 3701 | store to. If the runtime does not require a pointer to the object, Obj may be |
| 3702 | null.</p> |
Chris Lattner | d792391 | 2004-05-23 21:06:01 +0000 | [diff] [blame] | 3703 | |
| 3704 | <h5>Semantics:</h5> |
| 3705 | |
| 3706 | <p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store |
| 3707 | instruction, but may be replaced with substantially more complex code by the |
| 3708 | garbage collector runtime, as needed.</p> |
| 3709 | |
| 3710 | </div> |
| 3711 | |
| 3712 | |
| 3713 | |
| 3714 | <!-- ======================================================================= --> |
| 3715 | <div class="doc_subsection"> |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 3716 | <a name="int_codegen">Code Generator Intrinsics</a> |
| 3717 | </div> |
| 3718 | |
| 3719 | <div class="doc_text"> |
| 3720 | <p> |
| 3721 | These intrinsics are provided by LLVM to expose special features that may only |
| 3722 | be implemented with code generator support. |
| 3723 | </p> |
| 3724 | |
| 3725 | </div> |
| 3726 | |
| 3727 | <!-- _______________________________________________________________________ --> |
| 3728 | <div class="doc_subsubsection"> |
| 3729 | <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a> |
| 3730 | </div> |
| 3731 | |
| 3732 | <div class="doc_text"> |
| 3733 | |
| 3734 | <h5>Syntax:</h5> |
| 3735 | <pre> |
Chris Lattner | fcf39d4 | 2006-01-13 01:20:27 +0000 | [diff] [blame] | 3736 | declare sbyte *%llvm.returnaddress(uint <level>) |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 3737 | </pre> |
| 3738 | |
| 3739 | <h5>Overview:</h5> |
| 3740 | |
| 3741 | <p> |
Chris Lattner | 32b5d71 | 2006-10-15 20:05:59 +0000 | [diff] [blame] | 3742 | The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a |
| 3743 | target-specific value indicating the return address of the current function |
| 3744 | or one of its callers. |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 3745 | </p> |
| 3746 | |
| 3747 | <h5>Arguments:</h5> |
| 3748 | |
| 3749 | <p> |
| 3750 | The argument to this intrinsic indicates which function to return the address |
| 3751 | for. Zero indicates the calling function, one indicates its caller, etc. The |
| 3752 | argument is <b>required</b> to be a constant integer value. |
| 3753 | </p> |
| 3754 | |
| 3755 | <h5>Semantics:</h5> |
| 3756 | |
| 3757 | <p> |
| 3758 | The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating |
| 3759 | the return address of the specified call frame, or zero if it cannot be |
| 3760 | identified. The value returned by this intrinsic is likely to be incorrect or 0 |
| 3761 | for arguments other than zero, so it should only be used for debugging purposes. |
| 3762 | </p> |
| 3763 | |
| 3764 | <p> |
| 3765 | Note that calling this intrinsic does not prevent function inlining or other |
Chris Lattner | b40bb38 | 2005-03-07 20:30:51 +0000 | [diff] [blame] | 3766 | aggressive transformations, so the value returned may not be that of the obvious |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 3767 | source-language caller. |
| 3768 | </p> |
| 3769 | </div> |
| 3770 | |
| 3771 | |
| 3772 | <!-- _______________________________________________________________________ --> |
| 3773 | <div class="doc_subsubsection"> |
| 3774 | <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a> |
| 3775 | </div> |
| 3776 | |
| 3777 | <div class="doc_text"> |
| 3778 | |
| 3779 | <h5>Syntax:</h5> |
| 3780 | <pre> |
Chris Lattner | fcf39d4 | 2006-01-13 01:20:27 +0000 | [diff] [blame] | 3781 | declare sbyte *%llvm.frameaddress(uint <level>) |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 3782 | </pre> |
| 3783 | |
| 3784 | <h5>Overview:</h5> |
| 3785 | |
| 3786 | <p> |
Chris Lattner | 32b5d71 | 2006-10-15 20:05:59 +0000 | [diff] [blame] | 3787 | The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the |
| 3788 | target-specific frame pointer value for the specified stack frame. |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 3789 | </p> |
| 3790 | |
| 3791 | <h5>Arguments:</h5> |
| 3792 | |
| 3793 | <p> |
| 3794 | The argument to this intrinsic indicates which function to return the frame |
| 3795 | pointer for. Zero indicates the calling function, one indicates its caller, |
| 3796 | etc. The argument is <b>required</b> to be a constant integer value. |
| 3797 | </p> |
| 3798 | |
| 3799 | <h5>Semantics:</h5> |
| 3800 | |
| 3801 | <p> |
| 3802 | The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating |
| 3803 | the frame address of the specified call frame, or zero if it cannot be |
| 3804 | identified. The value returned by this intrinsic is likely to be incorrect or 0 |
| 3805 | for arguments other than zero, so it should only be used for debugging purposes. |
| 3806 | </p> |
| 3807 | |
| 3808 | <p> |
| 3809 | Note that calling this intrinsic does not prevent function inlining or other |
Chris Lattner | b40bb38 | 2005-03-07 20:30:51 +0000 | [diff] [blame] | 3810 | aggressive transformations, so the value returned may not be that of the obvious |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 3811 | source-language caller. |
| 3812 | </p> |
| 3813 | </div> |
| 3814 | |
Chris Lattner | 9a9d7ac | 2005-02-28 19:24:19 +0000 | [diff] [blame] | 3815 | <!-- _______________________________________________________________________ --> |
| 3816 | <div class="doc_subsubsection"> |
Chris Lattner | 57e1f39 | 2006-01-13 02:03:13 +0000 | [diff] [blame] | 3817 | <a name="i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a> |
| 3818 | </div> |
| 3819 | |
| 3820 | <div class="doc_text"> |
| 3821 | |
| 3822 | <h5>Syntax:</h5> |
| 3823 | <pre> |
| 3824 | declare sbyte *%llvm.stacksave() |
| 3825 | </pre> |
| 3826 | |
| 3827 | <h5>Overview:</h5> |
| 3828 | |
| 3829 | <p> |
| 3830 | The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of |
| 3831 | the function stack, for use with <a href="#i_stackrestore"> |
| 3832 | <tt>llvm.stackrestore</tt></a>. This is useful for implementing language |
| 3833 | features like scoped automatic variable sized arrays in C99. |
| 3834 | </p> |
| 3835 | |
| 3836 | <h5>Semantics:</h5> |
| 3837 | |
| 3838 | <p> |
| 3839 | This intrinsic returns a opaque pointer value that can be passed to <a |
| 3840 | href="#i_stackrestore"><tt>llvm.stackrestore</tt></a>. When an |
| 3841 | <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from |
| 3842 | <tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the |
| 3843 | state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In |
| 3844 | practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack |
| 3845 | that were allocated after the <tt>llvm.stacksave</tt> was executed. |
| 3846 | </p> |
| 3847 | |
| 3848 | </div> |
| 3849 | |
| 3850 | <!-- _______________________________________________________________________ --> |
| 3851 | <div class="doc_subsubsection"> |
| 3852 | <a name="i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a> |
| 3853 | </div> |
| 3854 | |
| 3855 | <div class="doc_text"> |
| 3856 | |
| 3857 | <h5>Syntax:</h5> |
| 3858 | <pre> |
| 3859 | declare void %llvm.stackrestore(sbyte* %ptr) |
| 3860 | </pre> |
| 3861 | |
| 3862 | <h5>Overview:</h5> |
| 3863 | |
| 3864 | <p> |
| 3865 | The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of |
| 3866 | the function stack to the state it was in when the corresponding <a |
| 3867 | href="#llvm.stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is |
| 3868 | useful for implementing language features like scoped automatic variable sized |
| 3869 | arrays in C99. |
| 3870 | </p> |
| 3871 | |
| 3872 | <h5>Semantics:</h5> |
| 3873 | |
| 3874 | <p> |
| 3875 | See the description for <a href="#i_stacksave"><tt>llvm.stacksave</tt></a>. |
| 3876 | </p> |
| 3877 | |
| 3878 | </div> |
| 3879 | |
| 3880 | |
| 3881 | <!-- _______________________________________________________________________ --> |
| 3882 | <div class="doc_subsubsection"> |
Chris Lattner | 9a9d7ac | 2005-02-28 19:24:19 +0000 | [diff] [blame] | 3883 | <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a> |
| 3884 | </div> |
| 3885 | |
| 3886 | <div class="doc_text"> |
| 3887 | |
| 3888 | <h5>Syntax:</h5> |
| 3889 | <pre> |
Reid Spencer | a8d451e | 2005-04-26 20:50:44 +0000 | [diff] [blame] | 3890 | declare void %llvm.prefetch(sbyte * <address>, |
| 3891 | uint <rw>, uint <locality>) |
Chris Lattner | 9a9d7ac | 2005-02-28 19:24:19 +0000 | [diff] [blame] | 3892 | </pre> |
| 3893 | |
| 3894 | <h5>Overview:</h5> |
| 3895 | |
| 3896 | |
| 3897 | <p> |
| 3898 | The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert |
John Criswell | fc6b895 | 2005-05-16 16:17:45 +0000 | [diff] [blame] | 3899 | a prefetch instruction if supported; otherwise, it is a noop. Prefetches have |
| 3900 | no |
| 3901 | effect on the behavior of the program but can change its performance |
Chris Lattner | 2a61536 | 2005-02-28 19:47:14 +0000 | [diff] [blame] | 3902 | characteristics. |
Chris Lattner | 9a9d7ac | 2005-02-28 19:24:19 +0000 | [diff] [blame] | 3903 | </p> |
| 3904 | |
| 3905 | <h5>Arguments:</h5> |
| 3906 | |
| 3907 | <p> |
| 3908 | <tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier |
| 3909 | determining if the fetch should be for a read (0) or write (1), and |
| 3910 | <tt>locality</tt> is a temporal locality specifier ranging from (0) - no |
Chris Lattner | aeffb4a | 2005-03-07 20:31:38 +0000 | [diff] [blame] | 3911 | locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and |
Chris Lattner | 9a9d7ac | 2005-02-28 19:24:19 +0000 | [diff] [blame] | 3912 | <tt>locality</tt> arguments must be constant integers. |
| 3913 | </p> |
| 3914 | |
| 3915 | <h5>Semantics:</h5> |
| 3916 | |
| 3917 | <p> |
| 3918 | This intrinsic does not modify the behavior of the program. In particular, |
| 3919 | prefetches cannot trap and do not produce a value. On targets that support this |
| 3920 | intrinsic, the prefetch can provide hints to the processor cache for better |
| 3921 | performance. |
| 3922 | </p> |
| 3923 | |
| 3924 | </div> |
| 3925 | |
Andrew Lenharth | 7f4ec3b | 2005-03-28 20:05:49 +0000 | [diff] [blame] | 3926 | <!-- _______________________________________________________________________ --> |
| 3927 | <div class="doc_subsubsection"> |
| 3928 | <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a> |
| 3929 | </div> |
| 3930 | |
| 3931 | <div class="doc_text"> |
| 3932 | |
| 3933 | <h5>Syntax:</h5> |
| 3934 | <pre> |
Reid Spencer | a8d451e | 2005-04-26 20:50:44 +0000 | [diff] [blame] | 3935 | declare void %llvm.pcmarker( uint <id> ) |
Andrew Lenharth | 7f4ec3b | 2005-03-28 20:05:49 +0000 | [diff] [blame] | 3936 | </pre> |
| 3937 | |
| 3938 | <h5>Overview:</h5> |
| 3939 | |
| 3940 | |
| 3941 | <p> |
John Criswell | fc6b895 | 2005-05-16 16:17:45 +0000 | [diff] [blame] | 3942 | The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter |
| 3943 | (PC) in a region of |
Andrew Lenharth | 7f4ec3b | 2005-03-28 20:05:49 +0000 | [diff] [blame] | 3944 | code to simulators and other tools. The method is target specific, but it is |
| 3945 | expected that the marker will use exported symbols to transmit the PC of the marker. |
Jeff Cohen | 25d4f7e | 2005-11-11 02:15:27 +0000 | [diff] [blame] | 3946 | The marker makes no guarantees that it will remain with any specific instruction |
Chris Lattner | d07c3f4 | 2005-11-15 06:07:55 +0000 | [diff] [blame] | 3947 | after optimizations. It is possible that the presence of a marker will inhibit |
Chris Lattner | b3e7afd | 2006-03-24 07:16:10 +0000 | [diff] [blame] | 3948 | optimizations. The intended use is to be inserted after optimizations to allow |
John Criswell | fc6b895 | 2005-05-16 16:17:45 +0000 | [diff] [blame] | 3949 | correlations of simulation runs. |
Andrew Lenharth | 7f4ec3b | 2005-03-28 20:05:49 +0000 | [diff] [blame] | 3950 | </p> |
| 3951 | |
| 3952 | <h5>Arguments:</h5> |
| 3953 | |
| 3954 | <p> |
| 3955 | <tt>id</tt> is a numerical id identifying the marker. |
| 3956 | </p> |
| 3957 | |
| 3958 | <h5>Semantics:</h5> |
| 3959 | |
| 3960 | <p> |
| 3961 | This intrinsic does not modify the behavior of the program. Backends that do not |
| 3962 | support this intrinisic may ignore it. |
| 3963 | </p> |
| 3964 | |
| 3965 | </div> |
| 3966 | |
Andrew Lenharth | 51b8d54 | 2005-11-11 16:47:30 +0000 | [diff] [blame] | 3967 | <!-- _______________________________________________________________________ --> |
| 3968 | <div class="doc_subsubsection"> |
| 3969 | <a name="i_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a> |
| 3970 | </div> |
| 3971 | |
| 3972 | <div class="doc_text"> |
| 3973 | |
| 3974 | <h5>Syntax:</h5> |
| 3975 | <pre> |
| 3976 | declare ulong %llvm.readcyclecounter( ) |
| 3977 | </pre> |
| 3978 | |
| 3979 | <h5>Overview:</h5> |
| 3980 | |
| 3981 | |
| 3982 | <p> |
| 3983 | The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle |
| 3984 | counter register (or similar low latency, high accuracy clocks) on those targets |
| 3985 | that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC. |
| 3986 | As the backing counters overflow quickly (on the order of 9 seconds on alpha), this |
| 3987 | should only be used for small timings. |
| 3988 | </p> |
| 3989 | |
| 3990 | <h5>Semantics:</h5> |
| 3991 | |
| 3992 | <p> |
| 3993 | When directly supported, reading the cycle counter should not modify any memory. |
| 3994 | Implementations are allowed to either return a application specific value or a |
| 3995 | system wide value. On backends without support, this is lowered to a constant 0. |
| 3996 | </p> |
| 3997 | |
| 3998 | </div> |
| 3999 | |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 4000 | <!-- ======================================================================= --> |
| 4001 | <div class="doc_subsection"> |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 4002 | <a name="int_libc">Standard C Library Intrinsics</a> |
| 4003 | </div> |
| 4004 | |
| 4005 | <div class="doc_text"> |
| 4006 | <p> |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 4007 | LLVM provides intrinsics for a few important standard C library functions. |
| 4008 | These intrinsics allow source-language front-ends to pass information about the |
| 4009 | alignment of the pointer arguments to the code generator, providing opportunity |
| 4010 | for more efficient code generation. |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 4011 | </p> |
| 4012 | |
| 4013 | </div> |
| 4014 | |
| 4015 | <!-- _______________________________________________________________________ --> |
| 4016 | <div class="doc_subsubsection"> |
| 4017 | <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a> |
| 4018 | </div> |
| 4019 | |
| 4020 | <div class="doc_text"> |
| 4021 | |
| 4022 | <h5>Syntax:</h5> |
| 4023 | <pre> |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4024 | declare void %llvm.memcpy.i32(sbyte* <dest>, sbyte* <src>, |
| 4025 | uint <len>, uint <align>) |
| 4026 | declare void %llvm.memcpy.i64(sbyte* <dest>, sbyte* <src>, |
| 4027 | ulong <len>, uint <align>) |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 4028 | </pre> |
| 4029 | |
| 4030 | <h5>Overview:</h5> |
| 4031 | |
| 4032 | <p> |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4033 | The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 4034 | location to the destination location. |
| 4035 | </p> |
| 4036 | |
| 4037 | <p> |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4038 | Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt> |
| 4039 | intrinsics do not return a value, and takes an extra alignment argument. |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 4040 | </p> |
| 4041 | |
| 4042 | <h5>Arguments:</h5> |
| 4043 | |
| 4044 | <p> |
| 4045 | The first argument is a pointer to the destination, the second is a pointer to |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4046 | the source. The third argument is an integer argument |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 4047 | specifying the number of bytes to copy, and the fourth argument is the alignment |
| 4048 | of the source and destination locations. |
| 4049 | </p> |
| 4050 | |
Chris Lattner | 3301ced | 2004-02-12 21:18:15 +0000 | [diff] [blame] | 4051 | <p> |
| 4052 | If the call to this intrinisic has an alignment value that is not 0 or 1, then |
Chris Lattner | f0afc2c | 2006-03-04 00:02:10 +0000 | [diff] [blame] | 4053 | the caller guarantees that both the source and destination pointers are aligned |
| 4054 | to that boundary. |
Chris Lattner | 3301ced | 2004-02-12 21:18:15 +0000 | [diff] [blame] | 4055 | </p> |
| 4056 | |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 4057 | <h5>Semantics:</h5> |
| 4058 | |
| 4059 | <p> |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4060 | The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source |
Chris Lattner | 33aec9e | 2004-02-12 17:01:32 +0000 | [diff] [blame] | 4061 | location to the destination location, which are not allowed to overlap. It |
| 4062 | copies "len" bytes of memory over. If the argument is known to be aligned to |
| 4063 | some boundary, this can be specified as the fourth argument, otherwise it should |
| 4064 | be set to 0 or 1. |
| 4065 | </p> |
| 4066 | </div> |
| 4067 | |
| 4068 | |
Chris Lattner | 0eb51b4 | 2004-02-12 18:10:10 +0000 | [diff] [blame] | 4069 | <!-- _______________________________________________________________________ --> |
| 4070 | <div class="doc_subsubsection"> |
| 4071 | <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a> |
| 4072 | </div> |
| 4073 | |
| 4074 | <div class="doc_text"> |
| 4075 | |
| 4076 | <h5>Syntax:</h5> |
| 4077 | <pre> |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4078 | declare void %llvm.memmove.i32(sbyte* <dest>, sbyte* <src>, |
| 4079 | uint <len>, uint <align>) |
| 4080 | declare void %llvm.memmove.i64(sbyte* <dest>, sbyte* <src>, |
| 4081 | ulong <len>, uint <align>) |
Chris Lattner | 0eb51b4 | 2004-02-12 18:10:10 +0000 | [diff] [blame] | 4082 | </pre> |
| 4083 | |
| 4084 | <h5>Overview:</h5> |
| 4085 | |
| 4086 | <p> |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4087 | The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source |
| 4088 | location to the destination location. It is similar to the |
| 4089 | '<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap. |
Chris Lattner | 0eb51b4 | 2004-02-12 18:10:10 +0000 | [diff] [blame] | 4090 | </p> |
| 4091 | |
| 4092 | <p> |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4093 | Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt> |
| 4094 | intrinsics do not return a value, and takes an extra alignment argument. |
Chris Lattner | 0eb51b4 | 2004-02-12 18:10:10 +0000 | [diff] [blame] | 4095 | </p> |
| 4096 | |
| 4097 | <h5>Arguments:</h5> |
| 4098 | |
| 4099 | <p> |
| 4100 | The first argument is a pointer to the destination, the second is a pointer to |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4101 | the source. The third argument is an integer argument |
Chris Lattner | 0eb51b4 | 2004-02-12 18:10:10 +0000 | [diff] [blame] | 4102 | specifying the number of bytes to copy, and the fourth argument is the alignment |
| 4103 | of the source and destination locations. |
| 4104 | </p> |
| 4105 | |
Chris Lattner | 3301ced | 2004-02-12 21:18:15 +0000 | [diff] [blame] | 4106 | <p> |
| 4107 | If the call to this intrinisic has an alignment value that is not 0 or 1, then |
Chris Lattner | f0afc2c | 2006-03-04 00:02:10 +0000 | [diff] [blame] | 4108 | the caller guarantees that the source and destination pointers are aligned to |
| 4109 | that boundary. |
Chris Lattner | 3301ced | 2004-02-12 21:18:15 +0000 | [diff] [blame] | 4110 | </p> |
| 4111 | |
Chris Lattner | 0eb51b4 | 2004-02-12 18:10:10 +0000 | [diff] [blame] | 4112 | <h5>Semantics:</h5> |
| 4113 | |
| 4114 | <p> |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4115 | The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source |
Chris Lattner | 0eb51b4 | 2004-02-12 18:10:10 +0000 | [diff] [blame] | 4116 | location to the destination location, which may overlap. It |
| 4117 | copies "len" bytes of memory over. If the argument is known to be aligned to |
| 4118 | some boundary, this can be specified as the fourth argument, otherwise it should |
| 4119 | be set to 0 or 1. |
| 4120 | </p> |
| 4121 | </div> |
| 4122 | |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 4123 | |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 4124 | <!-- _______________________________________________________________________ --> |
| 4125 | <div class="doc_subsubsection"> |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4126 | <a name="i_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a> |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 4127 | </div> |
| 4128 | |
| 4129 | <div class="doc_text"> |
| 4130 | |
| 4131 | <h5>Syntax:</h5> |
| 4132 | <pre> |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4133 | declare void %llvm.memset.i32(sbyte* <dest>, ubyte <val>, |
| 4134 | uint <len>, uint <align>) |
| 4135 | declare void %llvm.memset.i64(sbyte* <dest>, ubyte <val>, |
| 4136 | ulong <len>, uint <align>) |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 4137 | </pre> |
| 4138 | |
| 4139 | <h5>Overview:</h5> |
| 4140 | |
| 4141 | <p> |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4142 | The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 4143 | byte value. |
| 4144 | </p> |
| 4145 | |
| 4146 | <p> |
| 4147 | Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic |
| 4148 | does not return a value, and takes an extra alignment argument. |
| 4149 | </p> |
| 4150 | |
| 4151 | <h5>Arguments:</h5> |
| 4152 | |
| 4153 | <p> |
| 4154 | The first argument is a pointer to the destination to fill, the second is the |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4155 | byte value to fill it with, the third argument is an integer |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 4156 | argument specifying the number of bytes to fill, and the fourth argument is the |
| 4157 | known alignment of destination location. |
| 4158 | </p> |
| 4159 | |
| 4160 | <p> |
| 4161 | If the call to this intrinisic has an alignment value that is not 0 or 1, then |
Chris Lattner | f0afc2c | 2006-03-04 00:02:10 +0000 | [diff] [blame] | 4162 | the caller guarantees that the destination pointer is aligned to that boundary. |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 4163 | </p> |
| 4164 | |
| 4165 | <h5>Semantics:</h5> |
| 4166 | |
| 4167 | <p> |
Chris Lattner | 5b310c3 | 2006-03-03 00:07:20 +0000 | [diff] [blame] | 4168 | The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at |
| 4169 | the |
Chris Lattner | 1061064 | 2004-02-14 04:08:35 +0000 | [diff] [blame] | 4170 | destination location. If the argument is known to be aligned to some boundary, |
| 4171 | this can be specified as the fourth argument, otherwise it should be set to 0 or |
| 4172 | 1. |
| 4173 | </p> |
| 4174 | </div> |
| 4175 | |
| 4176 | |
Chris Lattner | 3200628 | 2004-06-11 02:28:03 +0000 | [diff] [blame] | 4177 | <!-- _______________________________________________________________________ --> |
| 4178 | <div class="doc_subsubsection"> |
Reid Spencer | 0b11820 | 2006-01-16 21:12:35 +0000 | [diff] [blame] | 4179 | <a name="i_isunordered">'<tt>llvm.isunordered.*</tt>' Intrinsic</a> |
Alkis Evlogimenos | 26bbe93 | 2004-06-13 01:16:15 +0000 | [diff] [blame] | 4180 | </div> |
| 4181 | |
| 4182 | <div class="doc_text"> |
| 4183 | |
| 4184 | <h5>Syntax:</h5> |
| 4185 | <pre> |
Reid Spencer | 0b11820 | 2006-01-16 21:12:35 +0000 | [diff] [blame] | 4186 | declare bool %llvm.isunordered.f32(float Val1, float Val2) |
| 4187 | declare bool %llvm.isunordered.f64(double Val1, double Val2) |
Alkis Evlogimenos | 26bbe93 | 2004-06-13 01:16:15 +0000 | [diff] [blame] | 4188 | </pre> |
| 4189 | |
| 4190 | <h5>Overview:</h5> |
| 4191 | |
| 4192 | <p> |
Reid Spencer | 0b11820 | 2006-01-16 21:12:35 +0000 | [diff] [blame] | 4193 | The '<tt>llvm.isunordered</tt>' intrinsics return true if either or both of the |
Alkis Evlogimenos | 26bbe93 | 2004-06-13 01:16:15 +0000 | [diff] [blame] | 4194 | specified floating point values is a NAN. |
| 4195 | </p> |
| 4196 | |
| 4197 | <h5>Arguments:</h5> |
| 4198 | |
| 4199 | <p> |
| 4200 | The arguments are floating point numbers of the same type. |
| 4201 | </p> |
| 4202 | |
| 4203 | <h5>Semantics:</h5> |
| 4204 | |
| 4205 | <p> |
| 4206 | If either or both of the arguments is a SNAN or QNAN, it returns true, otherwise |
| 4207 | false. |
| 4208 | </p> |
| 4209 | </div> |
| 4210 | |
| 4211 | |
Chris Lattner | a4d7414 | 2005-07-21 01:29:16 +0000 | [diff] [blame] | 4212 | <!-- _______________________________________________________________________ --> |
| 4213 | <div class="doc_subsubsection"> |
Chris Lattner | ec6cb61 | 2006-01-16 22:38:59 +0000 | [diff] [blame] | 4214 | <a name="i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a> |
Chris Lattner | a4d7414 | 2005-07-21 01:29:16 +0000 | [diff] [blame] | 4215 | </div> |
| 4216 | |
| 4217 | <div class="doc_text"> |
| 4218 | |
| 4219 | <h5>Syntax:</h5> |
| 4220 | <pre> |
Chris Lattner | f4d252d | 2006-09-08 06:34:02 +0000 | [diff] [blame] | 4221 | declare float %llvm.sqrt.f32(float %Val) |
| 4222 | declare double %llvm.sqrt.f64(double %Val) |
Chris Lattner | a4d7414 | 2005-07-21 01:29:16 +0000 | [diff] [blame] | 4223 | </pre> |
| 4224 | |
| 4225 | <h5>Overview:</h5> |
| 4226 | |
| 4227 | <p> |
Reid Spencer | 0b11820 | 2006-01-16 21:12:35 +0000 | [diff] [blame] | 4228 | The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand, |
Chris Lattner | a4d7414 | 2005-07-21 01:29:16 +0000 | [diff] [blame] | 4229 | returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike |
| 4230 | <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for |
| 4231 | negative numbers (which allows for better optimization). |
| 4232 | </p> |
| 4233 | |
| 4234 | <h5>Arguments:</h5> |
| 4235 | |
| 4236 | <p> |
| 4237 | The argument and return value are floating point numbers of the same type. |
| 4238 | </p> |
| 4239 | |
| 4240 | <h5>Semantics:</h5> |
| 4241 | |
| 4242 | <p> |
| 4243 | This function returns the sqrt of the specified operand if it is a positive |
| 4244 | floating point number. |
| 4245 | </p> |
| 4246 | </div> |
| 4247 | |
Chris Lattner | f4d252d | 2006-09-08 06:34:02 +0000 | [diff] [blame] | 4248 | <!-- _______________________________________________________________________ --> |
| 4249 | <div class="doc_subsubsection"> |
| 4250 | <a name="i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a> |
| 4251 | </div> |
| 4252 | |
| 4253 | <div class="doc_text"> |
| 4254 | |
| 4255 | <h5>Syntax:</h5> |
| 4256 | <pre> |
| 4257 | declare float %llvm.powi.f32(float %Val, int %power) |
| 4258 | declare double %llvm.powi.f64(double %Val, int %power) |
| 4259 | </pre> |
| 4260 | |
| 4261 | <h5>Overview:</h5> |
| 4262 | |
| 4263 | <p> |
| 4264 | The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the |
| 4265 | specified (positive or negative) power. The order of evaluation of |
| 4266 | multiplications is not defined. |
| 4267 | </p> |
| 4268 | |
| 4269 | <h5>Arguments:</h5> |
| 4270 | |
| 4271 | <p> |
| 4272 | The second argument is an integer power, and the first is a value to raise to |
| 4273 | that power. |
| 4274 | </p> |
| 4275 | |
| 4276 | <h5>Semantics:</h5> |
| 4277 | |
| 4278 | <p> |
| 4279 | This function returns the first value raised to the second power with an |
| 4280 | unspecified sequence of rounding operations.</p> |
| 4281 | </div> |
| 4282 | |
| 4283 | |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4284 | <!-- ======================================================================= --> |
| 4285 | <div class="doc_subsection"> |
Nate Begeman | 7e36c47 | 2006-01-13 23:26:38 +0000 | [diff] [blame] | 4286 | <a name="int_manip">Bit Manipulation Intrinsics</a> |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4287 | </div> |
| 4288 | |
| 4289 | <div class="doc_text"> |
| 4290 | <p> |
Nate Begeman | 7e36c47 | 2006-01-13 23:26:38 +0000 | [diff] [blame] | 4291 | LLVM provides intrinsics for a few important bit manipulation operations. |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4292 | These allow efficient code generation for some algorithms. |
| 4293 | </p> |
| 4294 | |
| 4295 | </div> |
| 4296 | |
| 4297 | <!-- _______________________________________________________________________ --> |
| 4298 | <div class="doc_subsubsection"> |
Nate Begeman | 7e36c47 | 2006-01-13 23:26:38 +0000 | [diff] [blame] | 4299 | <a name="i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a> |
| 4300 | </div> |
| 4301 | |
| 4302 | <div class="doc_text"> |
| 4303 | |
| 4304 | <h5>Syntax:</h5> |
| 4305 | <pre> |
Chris Lattner | ec6cb61 | 2006-01-16 22:38:59 +0000 | [diff] [blame] | 4306 | declare ushort %llvm.bswap.i16(ushort <id>) |
| 4307 | declare uint %llvm.bswap.i32(uint <id>) |
| 4308 | declare ulong %llvm.bswap.i64(ulong <id>) |
Nate Begeman | 7e36c47 | 2006-01-13 23:26:38 +0000 | [diff] [blame] | 4309 | </pre> |
| 4310 | |
| 4311 | <h5>Overview:</h5> |
| 4312 | |
| 4313 | <p> |
| 4314 | The '<tt>llvm.bwsap</tt>' family of intrinsics is used to byteswap a 16, 32 or |
| 4315 | 64 bit quantity. These are useful for performing operations on data that is not |
| 4316 | in the target's native byte order. |
| 4317 | </p> |
| 4318 | |
| 4319 | <h5>Semantics:</h5> |
| 4320 | |
| 4321 | <p> |
Chris Lattner | ec6cb61 | 2006-01-16 22:38:59 +0000 | [diff] [blame] | 4322 | The <tt>llvm.bswap.16</tt> intrinsic returns a ushort value that has the high and low |
| 4323 | byte of the input ushort swapped. Similarly, the <tt>llvm.bswap.i32</tt> intrinsic |
Nate Begeman | 7e36c47 | 2006-01-13 23:26:38 +0000 | [diff] [blame] | 4324 | returns a uint value that has the four bytes of the input uint swapped, so that |
| 4325 | if the input bytes are numbered 0, 1, 2, 3 then the returned uint will have its |
Chris Lattner | ec6cb61 | 2006-01-16 22:38:59 +0000 | [diff] [blame] | 4326 | bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i64</tt> intrinsic extends this concept |
Nate Begeman | 7e36c47 | 2006-01-13 23:26:38 +0000 | [diff] [blame] | 4327 | to 64 bits. |
| 4328 | </p> |
| 4329 | |
| 4330 | </div> |
| 4331 | |
| 4332 | <!-- _______________________________________________________________________ --> |
| 4333 | <div class="doc_subsubsection"> |
Reid Spencer | 0b11820 | 2006-01-16 21:12:35 +0000 | [diff] [blame] | 4334 | <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a> |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4335 | </div> |
| 4336 | |
| 4337 | <div class="doc_text"> |
| 4338 | |
| 4339 | <h5>Syntax:</h5> |
| 4340 | <pre> |
Chris Lattner | ec6cb61 | 2006-01-16 22:38:59 +0000 | [diff] [blame] | 4341 | declare ubyte %llvm.ctpop.i8 (ubyte <src>) |
| 4342 | declare ushort %llvm.ctpop.i16(ushort <src>) |
| 4343 | declare uint %llvm.ctpop.i32(uint <src>) |
| 4344 | declare ulong %llvm.ctpop.i64(ulong <src>) |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4345 | </pre> |
| 4346 | |
| 4347 | <h5>Overview:</h5> |
| 4348 | |
| 4349 | <p> |
Chris Lattner | ec6cb61 | 2006-01-16 22:38:59 +0000 | [diff] [blame] | 4350 | The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a |
| 4351 | value. |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4352 | </p> |
| 4353 | |
| 4354 | <h5>Arguments:</h5> |
| 4355 | |
| 4356 | <p> |
Chris Lattner | cfe6b37 | 2005-05-07 01:46:40 +0000 | [diff] [blame] | 4357 | The only argument is the value to be counted. The argument may be of any |
Chris Lattner | ec6cb61 | 2006-01-16 22:38:59 +0000 | [diff] [blame] | 4358 | unsigned integer type. The return type must match the argument type. |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4359 | </p> |
| 4360 | |
| 4361 | <h5>Semantics:</h5> |
| 4362 | |
| 4363 | <p> |
| 4364 | The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable. |
| 4365 | </p> |
| 4366 | </div> |
| 4367 | |
| 4368 | <!-- _______________________________________________________________________ --> |
| 4369 | <div class="doc_subsubsection"> |
Chris Lattner | 8a886be | 2006-01-16 22:34:14 +0000 | [diff] [blame] | 4370 | <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a> |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4371 | </div> |
| 4372 | |
| 4373 | <div class="doc_text"> |
| 4374 | |
| 4375 | <h5>Syntax:</h5> |
| 4376 | <pre> |
Chris Lattner | ec6cb61 | 2006-01-16 22:38:59 +0000 | [diff] [blame] | 4377 | declare ubyte %llvm.ctlz.i8 (ubyte <src>) |
| 4378 | declare ushort %llvm.ctlz.i16(ushort <src>) |
| 4379 | declare uint %llvm.ctlz.i32(uint <src>) |
| 4380 | declare ulong %llvm.ctlz.i64(ulong <src>) |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4381 | </pre> |
| 4382 | |
| 4383 | <h5>Overview:</h5> |
| 4384 | |
| 4385 | <p> |
Reid Spencer | 0b11820 | 2006-01-16 21:12:35 +0000 | [diff] [blame] | 4386 | The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of |
| 4387 | leading zeros in a variable. |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4388 | </p> |
| 4389 | |
| 4390 | <h5>Arguments:</h5> |
| 4391 | |
| 4392 | <p> |
Chris Lattner | cfe6b37 | 2005-05-07 01:46:40 +0000 | [diff] [blame] | 4393 | The only argument is the value to be counted. The argument may be of any |
Chris Lattner | ec6cb61 | 2006-01-16 22:38:59 +0000 | [diff] [blame] | 4394 | unsigned integer type. The return type must match the argument type. |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4395 | </p> |
| 4396 | |
| 4397 | <h5>Semantics:</h5> |
| 4398 | |
| 4399 | <p> |
Chris Lattner | eff29ab | 2005-05-15 19:39:26 +0000 | [diff] [blame] | 4400 | The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros |
| 4401 | in a variable. If the src == 0 then the result is the size in bits of the type |
Chris Lattner | 99d3c27 | 2006-04-21 21:37:40 +0000 | [diff] [blame] | 4402 | of src. For example, <tt>llvm.ctlz(int 2) = 30</tt>. |
Andrew Lenharth | ec370fd | 2005-05-03 18:01:48 +0000 | [diff] [blame] | 4403 | </p> |
| 4404 | </div> |
Chris Lattner | 3200628 | 2004-06-11 02:28:03 +0000 | [diff] [blame] | 4405 | |
| 4406 | |
Chris Lattner | eff29ab | 2005-05-15 19:39:26 +0000 | [diff] [blame] | 4407 | |
| 4408 | <!-- _______________________________________________________________________ --> |
| 4409 | <div class="doc_subsubsection"> |
Chris Lattner | 8a886be | 2006-01-16 22:34:14 +0000 | [diff] [blame] | 4410 | <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a> |
Chris Lattner | eff29ab | 2005-05-15 19:39:26 +0000 | [diff] [blame] | 4411 | </div> |
| 4412 | |
| 4413 | <div class="doc_text"> |
| 4414 | |
| 4415 | <h5>Syntax:</h5> |
| 4416 | <pre> |
Chris Lattner | ec6cb61 | 2006-01-16 22:38:59 +0000 | [diff] [blame] | 4417 | declare ubyte %llvm.cttz.i8 (ubyte <src>) |
| 4418 | declare ushort %llvm.cttz.i16(ushort <src>) |
| 4419 | declare uint %llvm.cttz.i32(uint <src>) |
| 4420 | declare ulong %llvm.cttz.i64(ulong <src>) |
Chris Lattner | eff29ab | 2005-05-15 19:39:26 +0000 | [diff] [blame] | 4421 | </pre> |
| 4422 | |
| 4423 | <h5>Overview:</h5> |
| 4424 | |
| 4425 | <p> |
Reid Spencer | 0b11820 | 2006-01-16 21:12:35 +0000 | [diff] [blame] | 4426 | The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of |
| 4427 | trailing zeros. |
Chris Lattner | eff29ab | 2005-05-15 19:39:26 +0000 | [diff] [blame] | 4428 | </p> |
| 4429 | |
| 4430 | <h5>Arguments:</h5> |
| 4431 | |
| 4432 | <p> |
| 4433 | The only argument is the value to be counted. The argument may be of any |
Chris Lattner | ec6cb61 | 2006-01-16 22:38:59 +0000 | [diff] [blame] | 4434 | unsigned integer type. The return type must match the argument type. |
Chris Lattner | eff29ab | 2005-05-15 19:39:26 +0000 | [diff] [blame] | 4435 | </p> |
| 4436 | |
| 4437 | <h5>Semantics:</h5> |
| 4438 | |
| 4439 | <p> |
| 4440 | The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros |
| 4441 | in a variable. If the src == 0 then the result is the size in bits of the type |
| 4442 | of src. For example, <tt>llvm.cttz(2) = 1</tt>. |
| 4443 | </p> |
| 4444 | </div> |
| 4445 | |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 4446 | <!-- ======================================================================= --> |
| 4447 | <div class="doc_subsection"> |
| 4448 | <a name="int_debugger">Debugger Intrinsics</a> |
| 4449 | </div> |
| 4450 | |
| 4451 | <div class="doc_text"> |
| 4452 | <p> |
| 4453 | The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix), |
| 4454 | are described in the <a |
| 4455 | href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level |
| 4456 | Debugging</a> document. |
| 4457 | </p> |
| 4458 | </div> |
| 4459 | |
| 4460 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 4461 | <!-- *********************************************************************** --> |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 4462 | <hr> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 4463 | <address> |
| 4464 | <a href="http://jigsaw.w3.org/css-validator/check/referer"><img |
| 4465 | src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a> |
| 4466 | <a href="http://validator.w3.org/check/referer"><img |
| 4467 | src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a> |
| 4468 | |
| 4469 | <a href="mailto:sabre@nondot.org">Chris Lattner</a><br> |
Reid Spencer | 05fe4b0 | 2006-03-14 05:39:39 +0000 | [diff] [blame] | 4470 | <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br> |
Misha Brukman | daa4cb0 | 2004-03-01 17:47:27 +0000 | [diff] [blame] | 4471 | Last modified: $Date$ |
| 4472 | </address> |
Misha Brukman | 9d0919f | 2003-11-08 01:05:38 +0000 | [diff] [blame] | 4473 | </body> |
| 4474 | </html> |