diff options
author | David E. O'Brien <obrien@FreeBSD.org> | 2002-02-01 18:16:02 +0000 |
---|---|---|
committer | David E. O'Brien <obrien@FreeBSD.org> | 2002-02-01 18:16:02 +0000 |
commit | 1952e2e1c1be6f107fa3ce8b10025cfd1cd7943b (patch) | |
tree | 086d9d6c8fbd4fc8fe4495059332f66bc0f8d12b /contrib/gcc/predict.def | |
parent | d337ceafd72ec93f99dfbee5ea0e70ed180a2dd6 (diff) | |
download | src-1952e2e1c1be6f107fa3ce8b10025cfd1cd7943b.tar.gz src-1952e2e1c1be6f107fa3ce8b10025cfd1cd7943b.zip |
Notes
Diffstat (limited to 'contrib/gcc/predict.def')
-rw-r--r-- | contrib/gcc/predict.def | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/contrib/gcc/predict.def b/contrib/gcc/predict.def new file mode 100644 index 000000000000..1201625c4b6e --- /dev/null +++ b/contrib/gcc/predict.def @@ -0,0 +1,100 @@ +/* This file contains the definitions and documentation for the + builtins used in the GNU compiler. + Copyright (C) 2001 Free Software Foundation, Inc. + +This file is part of GCC. + +GCC is free software; you can redistribute it and/or modify it under +the terms of the GNU General Public License as published by the Free +Software Foundation; either version 2, or (at your option) any later +version. + +GCC is distributed in the hope that it will be useful, but WITHOUT ANY +WARRANTY; without even the implied warranty of MERCHANTABILITY or +FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License +for more details. + +You should have received a copy of the GNU General Public License +along with GCC; see the file COPYING. If not, write to the Free +Software Foundation, 59 Temple Place - Suite 330, Boston, MA +02111-1307, USA. */ + +/* Before including this file, you should define a macro: + + DEF_PREDICTOR (ENUM, NAME, HITRATE) + + This macro will be called once for each predictor. The ENUM will + be of type `enum predictor', and will enumerate all supported + predictors. The order of DEF_PREDICTOR calls is important, as + in the first match combining heuristics, the predictor appearing + first in this file will win. + + NAME is used in the debugging output to determine predictor type. + + HITRATE is the probability that edge predicted by predictor as taken + will be really taken (so it should be always above + REG_BR_PROB_BASE / 2). */ + + +/* A value used as final outcome of all heuristics. */ +DEF_PREDICTOR (PRED_COMBINED, "combined", PROB_ALWAYS, 0) + +/* An outcome estimated by Dempster-Shaffer theory. */ +DEF_PREDICTOR (PRED_DS_THEORY, "DS theory", PROB_ALWAYS, 0) + +/* An combined heuristics using probability determined by first + matching heuristics from this list. */ +DEF_PREDICTOR (PRED_FIRST_MATCH, "first match", PROB_ALWAYS, 0) + +/* Heuristic applying when no heuristic below applies. */ +DEF_PREDICTOR (PRED_NO_PREDICTION, "no prediction", PROB_ALWAYS, 0) + +/* Mark unconditional jump as taken. */ +DEF_PREDICTOR (PRED_UNCONDITIONAL, "unconditional jump", PROB_ALWAYS, + PRED_FLAG_FIRST_MATCH) + +/* Use number of loop iterations determined by loop unroller to set + probability. We don't want to use Dempster-Shaffer theory here, + as the predictions is exact. */ +DEF_PREDICTOR (PRED_LOOP_ITERATIONS, "loop iterations", PROB_ALWAYS, + PRED_FLAG_FIRST_MATCH) + +/* Hints dropped by user via __builtin_expect feature. */ +DEF_PREDICTOR (PRED_BUILTIN_EXPECT, "__builtin_expect", PROB_VERY_LIKELY, + PRED_FLAG_FIRST_MATCH) + +/* Branch to basic block containing call marked by noreturn attribute. */ +DEF_PREDICTOR (PRED_NORETURN, "noreturn call", HITRATE (99), + PRED_FLAG_FIRST_MATCH) + +/* Loopback edge is taken. */ +DEF_PREDICTOR (PRED_LOOP_BRANCH, "loop branch", HITRATE (89), + PRED_FLAG_FIRST_MATCH) + +/* Edge causing loop to terminate is probably not taken. */ +DEF_PREDICTOR (PRED_LOOP_EXIT, "loop exit", HITRATE (90), + PRED_FLAG_FIRST_MATCH) + +/* Condition emitted by preconditiong code to ensure that variable + setting number of iterations is greater than initial value of iterator. */ +DEF_PREDICTOR (PRED_LOOP_CONDITION, "loop condition", PROB_VERY_LIKELY, 0) + +/* Preconditioning makes linear list of branches. */ +DEF_PREDICTOR (PRED_LOOP_PRECONDITIONING, "loop preconditioning", PROB_VERY_LIKELY, 0) + +/* Copied condition for the first iteration of loop is probably true. */ +DEF_PREDICTOR (PRED_LOOP_HEADER, "loop header", HITRATE (64), 0) + +/* Pointers are usually not NULL. */ +DEF_PREDICTOR (PRED_POINTER, "pointer", HITRATE (81), 0) + +/* NE is probable, EQ not etc... */ +DEF_PREDICTOR (PRED_OPCODE_POSITIVE, "opcode values positive", HITRATE (79), 0) +DEF_PREDICTOR (PRED_OPCODE_NONEQUAL, "opcode values nonequal", HITRATE (71), 0) +DEF_PREDICTOR (PRED_FPOPCODE, "fp_opcode", HITRATE (90), 0) + +/* Branch guarding call is probably taken. */ +DEF_PREDICTOR (PRED_CALL, "call", HITRATE (70), 0) + +/* Branch causing function to terminate is probably not taken. */ +DEF_PREDICTOR (PRED_ERROR_RETURN, "error return", HITRATE (52), 0) |