GCC Middle and Back End API Reference
predict.h
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1/* Definitions for branch prediction routines in the GNU compiler.
2 Copyright (C) 2001-2025 Free Software Foundation, Inc.
3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify it under
7the terms of the GNU General Public License as published by the Free
8Software Foundation; either version 3, or (at your option) any later
9version.
10
11GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12WARRANTY; without even the implied warranty of MERCHANTABILITY or
13FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14for more details.
15
16You should have received a copy of the GNU General Public License
17along with GCC; see the file COPYING3. If not see
18<http://www.gnu.org/licenses/>. */
19
20#ifndef GCC_PREDICT_H
21#define GCC_PREDICT_H
22
23#include "profile-count.h"
24
25/* Random guesstimation given names.
26 PROB_VERY_UNLIKELY should be small enough so basic block predicted
27 by it gets below HOT_BB_FREQUENCY_FRACTION. */
28#define PROB_VERY_UNLIKELY (REG_BR_PROB_BASE / 2000 - 1)
29#define PROB_EVEN (REG_BR_PROB_BASE / 2)
30#define PROB_VERY_LIKELY (REG_BR_PROB_BASE - PROB_VERY_UNLIKELY)
31#define PROB_ALWAYS (REG_BR_PROB_BASE)
32#define PROB_UNLIKELY (REG_BR_PROB_BASE / 5 - 1)
33#define PROB_LIKELY (REG_BR_PROB_BASE - PROB_UNLIKELY)
34#define PROB_UNINITIALIZED (-1)
35
36#define DEF_PREDICTOR(ENUM, NAME, HITRATE, FLAGS) ENUM,
38{
39#include "predict.def"
40
41 /* Upper bound on non-language-specific builtins. */
42 END_PREDICTORS
43};
44#undef DEF_PREDICTOR
50
51/* In emit-rtl.cc. */
53
56extern bool maybe_hot_count_p (struct function *, profile_count);
57extern bool maybe_hot_bb_p (struct function *, const_basic_block);
58extern bool maybe_hot_edge_p (edge);
60extern bool probably_never_executed_edge_p (struct function *, edge);
62extern bool optimize_function_for_speed_p (struct function *);
70extern bool optimize_insn_for_speed_p (void);
73extern bool optimize_loop_for_speed_p (class loop *);
74extern bool optimize_loop_nest_for_speed_p (class loop *);
76extern bool predictable_edge_p (edge);
78extern void rtl_profile_for_edge (edge);
79extern void default_rtl_profile (void);
84extern void predict_insn_def (rtx_insn *, enum br_predictor, enum prediction);
85extern void rtl_predict_edge (edge, enum br_predictor, int);
86extern void gimple_predict_edge (edge, enum br_predictor, int);
88extern void predict_edge_def (edge, enum br_predictor, enum prediction);
89extern void invert_br_probabilities (rtx);
92extern void tree_estimate_probability (bool);
93extern void handle_missing_profiles (void);
94extern bool update_max_bb_count (void);
95extern bool expensive_function_p (int);
96extern void compute_function_frequency (void);
98extern const char *predictor_name (enum br_predictor);
99extern void rebuild_frequencies (void);
100extern void report_predictor_hitrates (void);
101extern void force_edge_cold (edge, bool);
102extern void propagate_unlikely_bbs_forward (void);
103
105
106/* In ipa-pure-const.cc */
107extern void warn_function_cold (tree);
108
109#endif /* GCC_PREDICT_H */
Definition cfgloop.h:120
Definition profile-count.h:147
struct basic_block_def * basic_block
Definition coretypes.h:355
struct rtx_def * rtx
Definition coretypes.h:57
optimize_size_level
Definition coretypes.h:460
class edge_def * edge
Definition coretypes.h:352
const struct rtx_def * const_rtx
Definition coretypes.h:58
const class edge_def * const_edge
Definition coretypes.h:353
const struct basic_block_def * const_basic_block
Definition coretypes.h:356
int64_t gcov_type
Definition coretypes.h:46
union tree_node * tree
Definition coretypes.h:97
optimization_type
Definition coretypes.h:282
profile_probability split_branch_probability
Definition emit-rtl.cc:209
prediction
Definition predict.h:46
@ TAKEN
Definition predict.h:48
@ NOT_TAKEN
Definition predict.h:47
bool rtl_predicted_by_p(const_basic_block, enum br_predictor)
Definition predict.cc:493
void predict_edge_def(edge, enum br_predictor, enum prediction)
Definition predict.cc:740
void predict_insn_def(rtx_insn *, enum br_predictor, enum prediction)
Definition predict.cc:604
enum optimize_size_level optimize_function_for_size_p(struct function *)
Definition predict.cc:264
bool optimize_loop_nest_for_speed_p(class loop *)
Definition predict.cc:395
void rebuild_frequencies(void)
Definition predict.cc:4432
bool probably_never_executed_bb_p(struct function *, const_basic_block)
Definition predict.cc:236
optimization_type function_optimization_type(struct function *)
Definition predict.cc:285
void rtl_profile_for_edge(edge)
Definition predict.cc:477
void rtl_profile_for_bb(basic_block)
Definition predict.cc:469
const char * predictor_name(enum br_predictor)
Definition predict.cc:4210
bool optimize_insn_for_speed_p(void)
Definition predict.cc:360
bool maybe_hot_bb_p(struct function *, const_basic_block)
Definition predict.cc:190
void report_predictor_hitrates(void)
Definition predict.cc:4596
bool predictable_edge_p(edge)
Definition predict.cc:453
bool maybe_hot_edge_p(edge)
Definition predict.cc:200
tree build_predict_expr(enum br_predictor, enum prediction)
Definition predict.cc:4201
void rtl_predict_edge(edge, enum br_predictor, int)
Definition predict.cc:619
void guess_outgoing_edge_probabilities(basic_block)
Definition predict.cc:2362
bool optimize_function_for_speed_p(struct function *)
Definition predict.cc:277
bool br_prob_note_reliable_p(const_rtx)
Definition predict.cc:581
void warn_function_cold(tree)
Definition ipa-pure-const.cc:290
bool gimple_predicted_by_p(const_basic_block, enum br_predictor)
Definition predict.cc:533
bool optimize_edge_for_speed_p(edge)
Definition predict.cc:341
bool optimize_bb_for_speed_p(const_basic_block)
Definition predict.cc:309
bool update_max_bb_count(void)
Definition predict.cc:3822
void invert_br_probabilities(rtx)
Definition predict.cc:755
void add_reg_br_prob_note(rtx_insn *, profile_probability)
Definition predict.cc:974
void remove_predictions_associated_with_edge(edge)
Definition predict.cc:698
void default_rtl_profile(void)
Definition predict.cc:484
void force_edge_cold(edge, bool)
Definition predict.cc:4632
bool edge_probability_reliable_p(const_edge)
Definition predict.cc:574
bool expensive_function_p(int)
Definition predict.cc:3841
void handle_missing_profiles(void)
Definition predict.cc:3752
enum optimize_size_level optimize_loop_nest_for_size_p(class loop *)
Definition predict.cc:423
enum optimize_size_level optimize_bb_for_size_p(const_basic_block)
Definition predict.cc:295
gcov_type get_hot_bb_threshold(void)
Definition predict.cc:126
bool probably_never_executed_edge_p(struct function *, edge)
Definition predict.cc:254
void tree_estimate_probability(bool)
Definition predict.cc:3261
br_predictor
Definition predict.h:38
enum optimize_size_level optimize_loop_for_size_p(class loop *)
Definition predict.cc:379
void compute_function_frequency(void)
Definition predict.cc:4151
void set_hot_bb_threshold(gcov_type)
Definition predict.cc:146
bool optimize_loop_for_speed_p(class loop *)
Definition predict.cc:387
optimization_type bb_optimization_type(const_basic_block)
Definition predict.cc:317
enum optimize_size_level optimize_insn_for_size_p(void)
Definition predict.cc:349
optimization_type insn_optimization_type()
Definition predict.cc:369
void propagate_unlikely_bbs_forward(void)
Definition predict.cc:3880
bool maybe_hot_count_p(struct function *, profile_count)
Definition predict.cc:154
void gimple_predict_edge(edge, enum br_predictor, int)
Definition predict.cc:638
void tree_guess_outgoing_edge_probabilities(basic_block)
Definition predict.cc:3306
enum optimize_size_level optimize_edge_for_size_p(edge)
Definition predict.cc:327
Definition function.h:249
Definition profile-count.h:750
Definition rtl.h:546