gcc/predict.h

   1 /* Definitions for branch prediction routines in the GNU compiler.
   2    Copyright (C) 2001-2024 Free Software Foundation, Inc.
   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 #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,
  37 enum br_predictor
  38 {
  39 #include "predict.def"
  40
  41   /* Upper bound on non-language-specific builtins.  */
  42   END_PREDICTORS
  43 };
  44 #undef DEF_PREDICTOR
  45 enum prediction
  46 {
  47    NOT_TAKEN,
  48    TAKEN
  49 };
  50
  51 /* In emit-rtl.cc.  */
  52 extern profile_probability split_branch_probability;
  53
  54 extern gcov_type get_hot_bb_threshold (void);
  55 extern void set_hot_bb_threshold (gcov_type);
  56 extern bool maybe_hot_count_p (struct function *, profile_count);
  57 extern bool maybe_hot_bb_p (struct function *, const_basic_block);
  58 extern bool maybe_hot_edge_p (edge);
  59 extern bool probably_never_executed_bb_p (struct function *, const_basic_block);
  60 extern bool probably_never_executed_edge_p (struct function *, edge);
  61 extern enum optimize_size_level optimize_function_for_size_p (struct function *);
  62 extern bool optimize_function_for_speed_p (struct function *);
  63 extern optimization_type function_optimization_type (struct function *);
  64 extern enum optimize_size_level optimize_bb_for_size_p (const_basic_block);
  65 extern bool optimize_bb_for_speed_p (const_basic_block);
  66 extern optimization_type bb_optimization_type (const_basic_block);
  67 extern enum optimize_size_level optimize_edge_for_size_p (edge);
  68 extern bool optimize_edge_for_speed_p (edge);
  69 extern enum optimize_size_level optimize_insn_for_size_p (void);
  70 extern bool optimize_insn_for_speed_p (void);
  71 extern optimization_type insn_optimization_type ();
  72 extern enum optimize_size_level optimize_loop_for_size_p (class loop *);
  73 extern bool optimize_loop_for_speed_p (class loop *);
  74 extern bool optimize_loop_nest_for_speed_p (class loop *);
  75 extern enum optimize_size_level optimize_loop_nest_for_size_p (class loop *);
  76 extern bool predictable_edge_p (edge);
  77 extern void rtl_profile_for_bb (basic_block);
  78 extern void rtl_profile_for_edge (edge);
  79 extern void default_rtl_profile (void);
  80 extern bool rtl_predicted_by_p (const_basic_block, enum br_predictor);
  81 extern bool gimple_predicted_by_p (const_basic_block, enum br_predictor);
  82 extern bool edge_probability_reliable_p (const_edge);
  83 extern bool br_prob_note_reliable_p (const_rtx);
  84 extern void predict_insn_def (rtx_insn *, enum br_predictor, enum prediction);
  85 extern void rtl_predict_edge (edge, enum br_predictor, int);
  86 extern void gimple_predict_edge (edge, enum br_predictor, int);
  87 extern void remove_predictions_associated_with_edge (edge);
  88 extern void predict_edge_def (edge, enum br_predictor, enum prediction);
  89 extern void invert_br_probabilities (rtx);
  90 extern void guess_outgoing_edge_probabilities (basic_block);
  91 extern void tree_guess_outgoing_edge_probabilities (basic_block);
  92 extern void tree_estimate_probability (bool);
  93 extern void handle_missing_profiles (void);
  94 extern bool update_max_bb_count (void);
  95 extern bool expensive_function_p (int);
  96 extern void compute_function_frequency (void);
  97 extern tree build_predict_expr (enum br_predictor, enum prediction);
  98 extern const char *predictor_name (enum br_predictor);
  99 extern void rebuild_frequencies (void);
 100 extern void report_predictor_hitrates (void);
 101 extern void force_edge_cold (edge, bool);
 102 extern void propagate_unlikely_bbs_forward (void);
 103
 104 extern void add_reg_br_prob_note (rtx_insn *, profile_probability);
 105
 106 /* In ipa-pure-const.cc   */
 107 extern void warn_function_cold (tree);
 108
 109 #endif  /* GCC_PREDICT_H */