Mercurial > hg > CbC > CbC_gcc
annotate gcc/predict.def @ 111:04ced10e8804
gcc 7
| author | kono |
|---|---|
| date | Fri, 27 Oct 2017 22:46:09 +0900 |
| parents | 77e2b8dfacca |
| children | 84e7813d76e9 |
| rev | line source |
|---|---|
| 0 | 1 /* Definitions for the branch prediction routines in the GNU compiler. |
| 111 | 2 Copyright (C) 2001-2017 Free Software Foundation, Inc. |
| 0 | 3 |
| 4 This file is part of GCC. | |
| 5 | |
| 6 GCC is free software; you can redistribute it and/or modify it under | |
| 7 the terms of the GNU General Public License as published by the Free | |
| 8 Software Foundation; either version 3, or (at your option) any later | |
| 9 version. | |
| 10 | |
| 11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
| 12 WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 14 for more details. | |
| 15 | |
| 16 You should have received a copy of the GNU General Public License | |
| 17 along with GCC; see the file COPYING3. If not see | |
| 18 <http://www.gnu.org/licenses/>. */ | |
| 19 | |
| 20 /* Before including this file, you should define a macro: | |
| 21 | |
| 22 DEF_PREDICTOR (ENUM, NAME, HITRATE) | |
| 23 | |
| 24 This macro will be called once for each predictor. The ENUM will | |
| 25 be of type `enum predictor', and will enumerate all supported | |
| 26 predictors. The order of DEF_PREDICTOR calls is important, as | |
| 27 in the first match combining heuristics, the predictor appearing | |
| 28 first in this file will win. | |
| 29 | |
| 30 NAME is used in the debugging output to determine predictor type. | |
| 31 | |
| 32 HITRATE is the probability that edge predicted by predictor as taken | |
| 33 will be really taken (so it should be always above | |
| 34 REG_BR_PROB_BASE / 2). */ | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
35 |
| 0 | 36 |
| 37 /* A value used as final outcome of all heuristics. */ | |
| 38 DEF_PREDICTOR (PRED_COMBINED, "combined", PROB_ALWAYS, 0) | |
| 39 | |
| 40 /* An outcome estimated by Dempster-Shaffer theory. */ | |
| 41 DEF_PREDICTOR (PRED_DS_THEORY, "DS theory", PROB_ALWAYS, 0) | |
| 42 | |
| 43 /* A combined heuristics using probability determined by first | |
| 44 matching heuristics from this list. */ | |
| 45 DEF_PREDICTOR (PRED_FIRST_MATCH, "first match", PROB_ALWAYS, 0) | |
| 46 | |
| 47 /* Heuristic applying when no heuristic below applies. */ | |
| 48 DEF_PREDICTOR (PRED_NO_PREDICTION, "no prediction", PROB_ALWAYS, 0) | |
| 49 | |
| 50 /* Mark unconditional jump as taken. */ | |
| 51 DEF_PREDICTOR (PRED_UNCONDITIONAL, "unconditional jump", PROB_ALWAYS, | |
| 52 PRED_FLAG_FIRST_MATCH) | |
| 53 | |
| 54 /* Use number of loop iterations determined by # of iterations | |
| 55 analysis to set probability. We don't want to use Dempster-Shaffer | |
| 56 theory here, as the predictions is exact. */ | |
| 57 DEF_PREDICTOR (PRED_LOOP_ITERATIONS, "loop iterations", PROB_ALWAYS, | |
| 58 PRED_FLAG_FIRST_MATCH) | |
| 59 | |
| 111 | 60 /* Assume that any given atomic operation has low contention, |
| 61 and thus the compare-and-swap operation succeeds. */ | |
| 62 DEF_PREDICTOR (PRED_COMPARE_AND_SWAP, "compare and swap", PROB_VERY_LIKELY, | |
| 63 PRED_FLAG_FIRST_MATCH) | |
| 64 | |
| 65 /* Hints dropped by user via __builtin_expect feature. Note: the | |
| 66 probability of PROB_VERY_LIKELY is now overwritten by param | |
| 67 builtin_expect_probability with a default value of HITRATE(90). | |
| 68 Refer to param.def for details. */ | |
| 0 | 69 DEF_PREDICTOR (PRED_BUILTIN_EXPECT, "__builtin_expect", PROB_VERY_LIKELY, |
| 70 PRED_FLAG_FIRST_MATCH) | |
| 71 | |
| 72 /* Use number of loop iterations guessed by the contents of the loop. */ | |
| 73 DEF_PREDICTOR (PRED_LOOP_ITERATIONS_GUESSED, "guessed loop iterations", | |
| 74 PROB_ALWAYS, PRED_FLAG_FIRST_MATCH) | |
| 75 | |
| 111 | 76 /* Use number of loop iterations guessed by the contents of the loop. */ |
| 77 DEF_PREDICTOR (PRED_LOOP_ITERATIONS_MAX, "guessed loop iterations", | |
| 78 PROB_ALWAYS, PRED_FLAG_FIRST_MATCH) | |
| 79 | |
| 0 | 80 /* Branch containing goto is probably not taken. */ |
| 111 | 81 DEF_PREDICTOR (PRED_CONTINUE, "continue", HITRATE (67), 0) |
| 0 | 82 |
| 83 /* Branch to basic block containing call marked by noreturn attribute. */ | |
| 84 DEF_PREDICTOR (PRED_NORETURN, "noreturn call", PROB_VERY_LIKELY, | |
| 85 PRED_FLAG_FIRST_MATCH) | |
| 86 | |
| 87 /* Branch to basic block containing call marked by cold function attribute. */ | |
| 88 DEF_PREDICTOR (PRED_COLD_FUNCTION, "cold function call", PROB_VERY_LIKELY, | |
| 89 PRED_FLAG_FIRST_MATCH) | |
| 90 | |
| 111 | 91 /* Edge causing loop to terminate is probably not taken. */ |
| 92 DEF_PREDICTOR (PRED_LOOP_EXIT, "loop exit", HITRATE (85), | |
| 0 | 93 PRED_FLAG_FIRST_MATCH) |
| 94 | |
| 111 | 95 /* Same as LOOP_EXIT but for loops containing recursive call. */ |
| 96 DEF_PREDICTOR (PRED_LOOP_EXIT_WITH_RECURSION, "loop exit with recursion", | |
| 97 HITRATE (72), PRED_FLAG_FIRST_MATCH) | |
| 98 | |
| 99 /* Edge causing loop to terminate by computing value used by later | |
| 100 conditional. */ | |
| 101 DEF_PREDICTOR (PRED_LOOP_EXTRA_EXIT, "extra loop exit", HITRATE (83), | |
| 0 | 102 PRED_FLAG_FIRST_MATCH) |
| 103 | |
| 104 /* Pointers are usually not NULL. */ | |
| 111 | 105 DEF_PREDICTOR (PRED_POINTER, "pointer", HITRATE (70), 0) |
| 106 DEF_PREDICTOR (PRED_TREE_POINTER, "pointer (on trees)", HITRATE (70), 0) | |
| 0 | 107 |
| 108 /* NE is probable, EQ not etc... */ | |
| 111 | 109 DEF_PREDICTOR (PRED_OPCODE_POSITIVE, "opcode values positive", HITRATE (64), 0) |
| 110 DEF_PREDICTOR (PRED_OPCODE_NONEQUAL, "opcode values nonequal", HITRATE (66), 0) | |
| 0 | 111 DEF_PREDICTOR (PRED_FPOPCODE, "fp_opcode", HITRATE (90), 0) |
| 111 | 112 DEF_PREDICTOR (PRED_TREE_OPCODE_POSITIVE, "opcode values positive (on trees)", |
| 113 HITRATE (64), 0) | |
| 114 DEF_PREDICTOR (PRED_TREE_OPCODE_NONEQUAL, "opcode values nonequal (on trees)", | |
| 115 HITRATE (66), 0) | |
| 0 | 116 DEF_PREDICTOR (PRED_TREE_FPOPCODE, "fp_opcode (on trees)", HITRATE (90), 0) |
| 117 | |
| 118 /* Branch guarding call is probably taken. */ | |
| 111 | 119 DEF_PREDICTOR (PRED_CALL, "call", HITRATE (67), 0) |
| 120 | |
| 121 /* PRED_CALL is not very reliable predictor and it turns out to be even | |
| 122 less reliable for indirect calls and polymorphic calls. For spec2k6 | |
| 123 the predictio nis slightly in the direction of taking the call. */ | |
| 124 DEF_PREDICTOR (PRED_INDIR_CALL, "indirect call", HITRATE (86), 0) | |
| 125 DEF_PREDICTOR (PRED_POLYMORPHIC_CALL, "polymorphic call", HITRATE (59), 0) | |
| 126 | |
| 127 /* Recursive calls are usually not taken or the function will recurse | |
| 128 indefinitely. */ | |
| 129 DEF_PREDICTOR (PRED_RECURSIVE_CALL, "recursive call", HITRATE (75), 0) | |
| 0 | 130 |
| 131 /* Branch causing function to terminate is probably not taken. */ | |
| 111 | 132 DEF_PREDICTOR (PRED_TREE_EARLY_RETURN, "early return (on trees)", HITRATE (66), |
| 133 0) | |
| 0 | 134 |
| 135 /* Branch containing goto is probably not taken. */ | |
| 111 | 136 DEF_PREDICTOR (PRED_GOTO, "goto", HITRATE (66), 0) |
| 0 | 137 |
| 138 /* Branch ending with return constant is probably not taken. */ | |
| 111 | 139 DEF_PREDICTOR (PRED_CONST_RETURN, "const return", HITRATE (69), 0) |
| 0 | 140 |
| 141 /* Branch ending with return negative constant is probably not taken. */ | |
| 111 | 142 DEF_PREDICTOR (PRED_NEGATIVE_RETURN, "negative return", HITRATE (98), 0) |
| 0 | 143 |
| 144 /* Branch ending with return; is probably not taken */ | |
| 111 | 145 DEF_PREDICTOR (PRED_NULL_RETURN, "null return", HITRATE (91), 0) |
| 146 | |
| 147 /* Branches to compare induction variable to a loop bound is | |
| 148 extremely likely. */ | |
| 149 DEF_PREDICTOR (PRED_LOOP_IV_COMPARE_GUESS, "guess loop iv compare", | |
| 150 HITRATE (98), 0) | |
| 151 | |
| 152 /* Use number of loop iterations determined by # of iterations analysis | |
| 153 to set probability of branches that compares IV to loop bound variable. */ | |
| 154 DEF_PREDICTOR (PRED_LOOP_IV_COMPARE, "loop iv compare", PROB_VERY_LIKELY, | |
| 155 PRED_FLAG_FIRST_MATCH) | |
| 156 | |
| 157 /* In the following code | |
| 158 for (loop1) | |
| 159 if (cond) | |
| 160 for (loop2) | |
| 161 body; | |
| 162 guess that cond is unlikely. */ | |
| 163 DEF_PREDICTOR (PRED_LOOP_GUARD, "loop guard", HITRATE (66), 0) | |
| 164 | |
| 165 /* Same but for loops containing recursion. */ | |
| 166 DEF_PREDICTOR (PRED_LOOP_GUARD_WITH_RECURSION, "loop guard with recursion", | |
| 167 HITRATE (85), 0) | |
| 168 | |
| 169 /* Branches to hot labels are likely. */ | |
| 170 DEF_PREDICTOR (PRED_HOT_LABEL, "hot label", HITRATE (85), 0) | |
| 171 | |
| 172 /* Branches to cold labels are extremely unlikely. */ | |
| 173 DEF_PREDICTOR (PRED_COLD_LABEL, "cold label", PROB_VERY_LIKELY, | |
| 174 PRED_FLAG_FIRST_MATCH) | |
| 175 | |
| 176 | |
| 177 /* The following predictors are used in Fortran. */ | |
| 178 | |
| 179 /* Branch leading to an integer overflow are extremely unlikely. */ | |
| 180 DEF_PREDICTOR (PRED_FORTRAN_OVERFLOW, "Fortran overflow", PROB_ALWAYS, | |
| 181 PRED_FLAG_FIRST_MATCH) | |
| 0 | 182 |
| 111 | 183 /* Branch leading to a failure status are unlikely. This can occur for out |
| 184 of memory. This predictor only occurs when the user explicitly asked | |
| 185 for a return status. By default, the code aborts, | |
| 186 which is handled via PRED_NORETURN. */ | |
| 187 DEF_PREDICTOR (PRED_FORTRAN_FAIL_ALLOC, "Fortran fail alloc", | |
| 188 PROB_VERY_LIKELY, 0) | |
| 189 | |
| 190 /* Predictor is used for an allocation of an already allocated memory or | |
| 191 deallocating an already deallocated allocatable. */ | |
| 192 DEF_PREDICTOR (PRED_FORTRAN_REALLOC, "Fortran repeated allocation/deallocation", | |
| 193 PROB_LIKELY, 0) | |
| 194 | |
| 195 /* Branch leading to an I/O failure status are unlikely. This predictor is | |
| 196 used for I/O failures such as for invalid unit numbers. This predictor | |
| 197 only occurs when the user explicitly asked for a return status. By default, | |
| 198 the code aborts, which is handled via PRED_NORETURN. */ | |
| 199 DEF_PREDICTOR (PRED_FORTRAN_FAIL_IO, "Fortran fail IO", HITRATE (85), 0) | |
| 200 | |
| 201 /* Branch leading to a run-time warning message which is printed only once | |
| 202 are unlikely. The print-warning branch itself can be likely or unlikely. */ | |
| 203 DEF_PREDICTOR (PRED_FORTRAN_WARN_ONCE, "Fortran warn once", HITRATE (75), 0) | |
| 204 | |
| 205 /* Branch belonging to a zero-sized array. */ | |
| 206 DEF_PREDICTOR (PRED_FORTRAN_SIZE_ZERO, "Fortran zero-sized array", \ | |
| 207 HITRATE (99), 0) | |
| 208 | |
| 209 /* Branch belonging to an invalid bound index, in a context where it is | |
| 210 standard conform and well defined but rather pointless and, hence, rather | |
| 211 unlikely to occur. */ | |
| 212 DEF_PREDICTOR (PRED_FORTRAN_INVALID_BOUND, "Fortran invalid bound", \ | |
| 213 HITRATE (90), 0) | |
| 214 | |
| 215 /* Branch belonging to the handling of absent optional arguments. This | |
| 216 predictor is used when an optional dummy argument, associated with an | |
| 217 absent argument, is passed on as actual argument to another procedure, | |
| 218 which in turn has an optional argument. */ | |
| 219 DEF_PREDICTOR (PRED_FORTRAN_ABSENT_DUMMY, "Fortran absent dummy", \ | |
| 220 HITRATE (60), 0) | |
| 221 | |
| 222 /* Fortran DO statement generates a pre-header guard: | |
| 223 empty = (step > 0 ? to < from : to > from), which can be predicted | |
| 224 to be very likely. */ | |
| 225 DEF_PREDICTOR (PRED_FORTRAN_LOOP_PREHEADER, "Fortran loop preheader", \ | |
| 226 HITRATE (99), 0) |