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/* Data structures and function declarations for the SSA value propagation
Copyright (C) 2004-2020 Free Software Foundation, Inc.
Contributed by Diego Novillo <>
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 3, or (at your option)
any later version.
GCC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3. If not see
<>. */
/* If SIM_P is true, statement S will be simulated again. */
static inline void
prop_set_simulate_again (gimple *s, bool visit_p)
gimple_set_visited (s, visit_p);
/* Return true if statement T should be simulated again. */
static inline bool
prop_simulate_again_p (gimple *s)
return gimple_visited_p (s);
/* Lattice values used for propagation purposes. Specific instances
of a propagation engine must return these values from the statement
and PHI visit functions to direct the engine. */
enum ssa_prop_result {
/* The statement produces nothing of interest. No edges will be
added to the work lists. */
/* The statement produces an interesting value. The set SSA_NAMEs
returned by SSA_PROP_VISIT_STMT should be added to
INTERESTING_SSA_EDGES. If the statement being visited is a
conditional jump, SSA_PROP_VISIT_STMT should indicate which edge
out of the basic block should be marked executable. */
/* The statement produces a varying (i.e., useless) value and
should not be simulated again. If the statement being visited
is a conditional jump, all the edges coming out of the block
will be considered executable. */
extern bool valid_gimple_rhs_p (tree);
extern void move_ssa_defining_stmt_for_defs (gimple *, gimple *);
extern bool update_gimple_call (gimple_stmt_iterator *, tree, int, ...);
extern bool update_call_from_tree (gimple_stmt_iterator *, tree);
extern bool stmt_makes_single_store (gimple *);
extern bool may_propagate_copy (tree, tree, bool = false);
extern bool may_propagate_copy_into_stmt (gimple *, tree);
extern bool may_propagate_copy_into_asm (tree);
extern void propagate_value (use_operand_p, tree);
extern void replace_exp (use_operand_p, tree);
extern void propagate_tree_value (tree *, tree);
extern void propagate_tree_value_into_stmt (gimple_stmt_iterator *, tree);
/* Public interface into the SSA propagation engine. Clients should inherit
from this class and provide their own visitors. */
class ssa_propagation_engine
virtual ~ssa_propagation_engine (void) { }
/* Virtual functions the clients must provide to visit statements
and phi nodes respectively. */
virtual enum ssa_prop_result visit_stmt (gimple *, edge *, tree *) = 0;
virtual enum ssa_prop_result visit_phi (gphi *) = 0;
/* Main interface into the propagation engine. */
void ssa_propagate (void);
/* Internal implementation details. */
void simulate_stmt (gimple *stmt);
void simulate_block (basic_block);
class substitute_and_fold_engine
substitute_and_fold_engine (bool fold_all_stmts = false)
: fold_all_stmts (fold_all_stmts) { }
virtual ~substitute_and_fold_engine (void) { }
virtual bool fold_stmt (gimple_stmt_iterator *) { return false; }
virtual tree get_value (tree) { return NULL_TREE; }
bool substitute_and_fold (basic_block = NULL);
bool replace_uses_in (gimple *);
bool replace_phi_args_in (gphi *);
/* Users like VRP can set this when they want to perform
folding for every propagation. */
bool fold_all_stmts;
#endif /* _TREE_SSA_PROPAGATE_H */