/* Definitions for the branch prediction routines in the GNU compiler.
- Copyright (C) 2001, 2003, 2004 Free Software Foundation, Inc.
+ Copyright (C) 2001, 2003, 2004, 2007, 2008 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
+Software Foundation; either version 3, or (at your option) any later
version.
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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, 51 Franklin Street, Fifth Floor, Boston, MA
-02110-1301, USA. */
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
/* Before including this file, you should define a macro:
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)
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. */
+/* Use number of loop iterations determined by # of iterations
+ analysis 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)
-/* For guessed profiles, the loops having unknown number of iterations
- are predicted to iterate relatively few (10) times at average.
- For functions containing one loop with large known number of iterations
- and other loops having unbounded loops we would end up predicting all
- the other loops cold that is not usually the case. So we need to artifically
- flatten the profile.
-
- We need to cut the maximal predicted iterations to large enought iterations
- so the loop appears important, but safely within HOT_BB_COUNT_FRACTION
- range. */
-#define MAX_PRED_LOOP_ITERATIONS 100
-
/* Hints dropped by user via __builtin_expect feature. */
DEF_PREDICTOR (PRED_BUILTIN_EXPECT, "__builtin_expect", PROB_VERY_LIKELY,
PRED_FLAG_FIRST_MATCH)
+/* Use number of loop iterations guessed by the contents of the loop. */
+DEF_PREDICTOR (PRED_LOOP_ITERATIONS_GUESSED, "guessed loop iterations",
+ PROB_ALWAYS, PRED_FLAG_FIRST_MATCH)
+
/* Branch containing goto is probably not taken. */
-DEF_PREDICTOR (PRED_CONTINUE, "continue", HITRATE (56), 0)
+DEF_PREDICTOR (PRED_CONTINUE, "continue", HITRATE (50), 0)
/* Branch to basic block containing call marked by noreturn attribute. */
-DEF_PREDICTOR (PRED_NORETURN, "noreturn call", HITRATE (99),
+DEF_PREDICTOR (PRED_NORETURN, "noreturn call", PROB_VERY_LIKELY,
+ PRED_FLAG_FIRST_MATCH)
+
+/* Branch to basic block containing call marked by cold function attribute. */
+DEF_PREDICTOR (PRED_COLD_FUNCTION, "cold function call", PROB_VERY_LIKELY,
PRED_FLAG_FIRST_MATCH)
/* Loopback edge is taken. */
-DEF_PREDICTOR (PRED_LOOP_BRANCH, "loop branch", HITRATE (89),
+DEF_PREDICTOR (PRED_LOOP_BRANCH, "loop branch", HITRATE (86),
PRED_FLAG_FIRST_MATCH)
/* Edge causing loop to terminate is probably not taken. */
-DEF_PREDICTOR (PRED_LOOP_EXIT, "loop exit", HITRATE (90),
+DEF_PREDICTOR (PRED_LOOP_EXIT, "loop exit", HITRATE (91),
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)
-DEF_PREDICTOR (PRED_TREE_POINTER, "pointer (on trees)", HITRATE (81), 0)
+DEF_PREDICTOR (PRED_POINTER, "pointer", HITRATE (85), 0)
+DEF_PREDICTOR (PRED_TREE_POINTER, "pointer (on trees)", HITRATE (85), 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)
-DEF_PREDICTOR (PRED_TREE_OPCODE_POSITIVE, "opcode values positive (on trees)", HITRATE (79), 0)
-DEF_PREDICTOR (PRED_TREE_OPCODE_NONEQUAL, "opcode values nonequal (on trees)", HITRATE (71), 0)
+DEF_PREDICTOR (PRED_TREE_OPCODE_POSITIVE, "opcode values positive (on trees)", HITRATE (73), 0)
+DEF_PREDICTOR (PRED_TREE_OPCODE_NONEQUAL, "opcode values nonequal (on trees)", HITRATE (72), 0)
DEF_PREDICTOR (PRED_TREE_FPOPCODE, "fp_opcode (on trees)", HITRATE (90), 0)
/* Branch guarding call is probably taken. */
-DEF_PREDICTOR (PRED_CALL, "call", HITRATE (70), 0)
+DEF_PREDICTOR (PRED_CALL, "call", HITRATE (71), 0)
/* Branch causing function to terminate is probably not taken. */
-DEF_PREDICTOR (PRED_EARLY_RETURN, "early return", HITRATE (67), 0)
-DEF_PREDICTOR (PRED_TREE_EARLY_RETURN, "early return (on trees)", HITRATE (67), 0)
+DEF_PREDICTOR (PRED_TREE_EARLY_RETURN, "early return (on trees)", HITRATE (61), 0)
/* Branch containing goto is probably not taken. */
DEF_PREDICTOR (PRED_GOTO, "goto", HITRATE (70), 0)
/* Branch ending with return constant is probably not taken. */
-DEF_PREDICTOR (PRED_CONST_RETURN, "const return", HITRATE (95), 0)
+DEF_PREDICTOR (PRED_CONST_RETURN, "const return", HITRATE (67), 0)
/* Branch ending with return negative constant is probably not taken. */
DEF_PREDICTOR (PRED_NEGATIVE_RETURN, "negative return", HITRATE (96), 0)
DEF_PREDICTOR (PRED_NULL_RETURN, "null return", HITRATE (90), 0)
/* Branches to a mudflap bounds check are extremely unlikely. */
-DEF_PREDICTOR (PRED_MUDFLAP, "mudflap check", HITRATE (99), 0)
+DEF_PREDICTOR (PRED_MUDFLAP, "mudflap check", PROB_VERY_LIKELY, 0)
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