gcc/tree-ssa-propagate.h

   1 /* Data structures and function declarations for the SSA value propagation
   2    engine.
   3    Copyright (C) 2004-2022 Free Software Foundation, Inc.
   4    Contributed by Diego Novillo <dnovillo@redhat.com>
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 3, or (at your option)
  11 any later version.
  12
  13 GCC is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #ifndef _TREE_SSA_PROPAGATE_H
  23 #define _TREE_SSA_PROPAGATE_H 1
  24
  25 #include "value-query.h"
  26
  27 /* If SIM_P is true, statement S will be simulated again.  */
  28
  29 static inline void
  30 prop_set_simulate_again (gimple *s, bool visit_p)
  31 {
  32   gimple_set_visited (s, visit_p);
  33 }
  34
  35 /* Return true if statement T should be simulated again.  */
  36
  37 static inline bool
  38 prop_simulate_again_p (gimple *s)
  39 {
  40   return gimple_visited_p (s);
  41 }
  42
  43 /* Lattice values used for propagation purposes.  Specific instances
  44    of a propagation engine must return these values from the statement
  45    and PHI visit functions to direct the engine.  */
  46 enum ssa_prop_result {
  47     /* The statement produces nothing of interest.  No edges will be
  48        added to the work lists.  */
  49     SSA_PROP_NOT_INTERESTING,
  50
  51     /* The statement produces an interesting value.  The set SSA_NAMEs
  52        returned by SSA_PROP_VISIT_STMT should be added to
  53        INTERESTING_SSA_EDGES.  If the statement being visited is a
  54        conditional jump, SSA_PROP_VISIT_STMT should indicate which edge
  55        out of the basic block should be marked executable.  */
  56     SSA_PROP_INTERESTING,
  57
  58     /* The statement produces a varying (i.e., useless) value and
  59        should not be simulated again.  If the statement being visited
  60        is a conditional jump, all the edges coming out of the block
  61        will be considered executable.  */
  62     SSA_PROP_VARYING
  63 };
  64
  65
  66 extern void move_ssa_defining_stmt_for_defs (gimple *, gimple *);
  67 extern bool stmt_makes_single_store (gimple *);
  68 extern bool may_propagate_copy (tree, tree, bool = false);
  69 extern bool may_propagate_copy_into_stmt (gimple *, tree);
  70 extern bool may_propagate_copy_into_asm (tree);
  71 extern void propagate_value (use_operand_p, tree);
  72 extern void replace_exp (use_operand_p, tree);
  73 extern void propagate_tree_value (tree *, tree);
  74 extern void propagate_tree_value_into_stmt (gimple_stmt_iterator *, tree);
  75
  76 /* Public interface into the SSA propagation engine.  Clients should inherit
  77    from this class and provide their own visitors.  */
  78
  79 class ssa_propagation_engine
  80 {
  81  public:
  82
  83   virtual ~ssa_propagation_engine (void) { }
  84
  85   /* Virtual functions the clients must provide to visit statements
  86      and phi nodes respectively.  */
  87   virtual enum ssa_prop_result visit_stmt (gimple *, edge *, tree *) = 0;
  88   virtual enum ssa_prop_result visit_phi (gphi *) = 0;
  89
  90   /* Main interface into the propagation engine.  */
  91   void ssa_propagate (void);
  92
  93  private:
  94   /* Internal implementation details.  */
  95   void simulate_stmt (gimple *stmt);
  96   void simulate_block (basic_block);
  97 };
  98
  99 class substitute_and_fold_engine : public value_query
 100 {
 101  public:
 102   substitute_and_fold_engine (bool fold_all_stmts = false)
 103     : fold_all_stmts (fold_all_stmts) { }
 104   virtual ~substitute_and_fold_engine (void) { }
 105   virtual bool fold_stmt (gimple_stmt_iterator *) { return false; }
 106
 107   bool substitute_and_fold (basic_block = NULL);
 108   bool replace_uses_in (gimple *);
 109   bool replace_phi_args_in (gphi *);
 110
 111   virtual void pre_fold_bb (basic_block) { }
 112   virtual void post_fold_bb (basic_block) { }
 113   virtual void pre_fold_stmt (gimple *) { }
 114   virtual void post_new_stmt (gimple *) { }
 115
 116   bool propagate_into_phi_args (basic_block);
 117
 118   /* Users like VRP can set this when they want to perform
 119      folding for every propagation.  */
 120   bool fold_all_stmts;
 121 };
 122
 123 #endif /* _TREE_SSA_PROPAGATE_H  */