gcc/tree-ssa-propagate.h

   1 /* Data structures and function declarations for the SSA value propagation
   2    engine.
   3    Copyright (C) 2004-2020 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 /* If SIM_P is true, statement S will be simulated again.  */
  26
  27 static inline void
  28 prop_set_simulate_again (gimple *s, bool visit_p)
  29 {
  30   gimple_set_visited (s, visit_p);
  31 }
  32
  33 /* Return true if statement T should be simulated again.  */
  34
  35 static inline bool
  36 prop_simulate_again_p (gimple *s)
  37 {
  38   return gimple_visited_p (s);
  39 }
  40
  41 /* Lattice values used for propagation purposes.  Specific instances
  42    of a propagation engine must return these values from the statement
  43    and PHI visit functions to direct the engine.  */
  44 enum ssa_prop_result {
  45     /* The statement produces nothing of interest.  No edges will be
  46        added to the work lists.  */
  47     SSA_PROP_NOT_INTERESTING,
  48
  49     /* The statement produces an interesting value.  The set SSA_NAMEs
  50        returned by SSA_PROP_VISIT_STMT should be added to
  51        INTERESTING_SSA_EDGES.  If the statement being visited is a
  52        conditional jump, SSA_PROP_VISIT_STMT should indicate which edge
  53        out of the basic block should be marked executable.  */
  54     SSA_PROP_INTERESTING,
  55
  56     /* The statement produces a varying (i.e., useless) value and
  57        should not be simulated again.  If the statement being visited
  58        is a conditional jump, all the edges coming out of the block
  59        will be considered executable.  */
  60     SSA_PROP_VARYING
  61 };
  62
  63
  64 extern bool valid_gimple_rhs_p (tree);
  65 extern void move_ssa_defining_stmt_for_defs (gimple *, gimple *);
  66 extern bool update_gimple_call (gimple_stmt_iterator *, tree, int, ...);
  67 extern bool update_call_from_tree (gimple_stmt_iterator *, tree);
  68 extern bool stmt_makes_single_store (gimple *);
  69 extern bool may_propagate_copy (tree, tree);
  70 extern bool may_propagate_copy_into_stmt (gimple *, tree);
  71 extern bool may_propagate_copy_into_asm (tree);
  72 extern void propagate_value (use_operand_p, tree);
  73 extern void replace_exp (use_operand_p, tree);
  74 extern void propagate_tree_value (tree *, tree);
  75 extern void propagate_tree_value_into_stmt (gimple_stmt_iterator *, tree);
  76
  77 /* Public interface into the SSA propagation engine.  Clients should inherit
  78    from this class and provide their own visitors.  */
  79
  80 class ssa_propagation_engine
  81 {
  82  public:
  83
  84   virtual ~ssa_propagation_engine (void) { }
  85
  86   /* Virtual functions the clients must provide to visit statements
  87      and phi nodes respectively.  */
  88   virtual enum ssa_prop_result visit_stmt (gimple *, edge *, tree *) = 0;
  89   virtual enum ssa_prop_result visit_phi (gphi *) = 0;
  90
  91   /* Main interface into the propagation engine.  */
  92   void ssa_propagate (void);
  93
  94  private:
  95   /* Internal implementation details.  */
  96   void simulate_stmt (gimple *stmt);
  97   void simulate_block (basic_block);
  98 };
  99
 100 class substitute_and_fold_engine
 101 {
 102  public:
 103   substitute_and_fold_engine (bool fold_all_stmts = false)
 104     : fold_all_stmts (fold_all_stmts) { }
 105   virtual ~substitute_and_fold_engine (void) { }
 106   virtual bool fold_stmt (gimple_stmt_iterator *) { return false; }
 107   virtual tree get_value (tree) { return NULL_TREE; }
 108
 109   bool substitute_and_fold (basic_block = NULL);
 110   bool replace_uses_in (gimple *);
 111   bool replace_phi_args_in (gphi *);
 112
 113   /* Users like VRP can set this when they want to perform
 114      folding for every propagation.  */
 115   bool fold_all_stmts;
 116 };
 117
 118 #endif /* _TREE_SSA_PROPAGATE_H  */