1/* Data structures and function declarations for the SSA value propagation
2 engine.
3 Copyright (C) 2004-2023 Free Software Foundation, Inc.
4 Contributed by Diego Novillo <dnovillo@redhat.com>
5
6This file is part of GCC.
7
8GCC is free software; you can redistribute it and/or modify
9it under the terms of the GNU General Public License as published by
10the Free Software Foundation; either version 3, or (at your option)
11any later version.
12
13GCC is distributed in the hope that it will be useful,
14but WITHOUT ANY WARRANTY; without even the implied warranty of
15MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16GNU General Public License for more details.
17
18You should have received a copy of the GNU General Public License
19along 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
29inline void
30prop_set_simulate_again (gimple *s, bool visit_p)
31{
32 gimple_set_visited (stmt: s, visited_p: visit_p);
33}
34
35/* Return true if statement T should be simulated again. */
36
37inline bool
38prop_simulate_again_p (gimple *s)
39{
40 return gimple_visited_p (stmt: 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. */
46enum 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
66extern void move_ssa_defining_stmt_for_defs (gimple *, gimple *);
67extern bool stmt_makes_single_store (gimple *);
68extern bool may_propagate_copy (tree, tree, bool = false);
69extern bool may_propagate_copy_into_stmt (gimple *, tree);
70extern bool may_propagate_copy_into_asm (tree);
71extern void propagate_value (use_operand_p, tree);
72extern void replace_exp (use_operand_p, tree);
73extern void propagate_tree_value (tree *, tree);
74extern 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
79class 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
99class substitute_and_fold_engine : public range_query
100{
101 public:
102 substitute_and_fold_engine (bool fold_all_stmts = false)
103 : fold_all_stmts (fold_all_stmts) { }
104
105 virtual tree value_of_expr (tree expr, gimple * = NULL) = 0;
106 virtual tree value_on_edge (edge, tree expr) override;
107 virtual tree value_of_stmt (gimple *, tree name = NULL) override;
108 virtual bool range_of_expr (vrange &r, tree expr, gimple * = NULL);
109
110 virtual ~substitute_and_fold_engine (void) { }
111 virtual bool fold_stmt (gimple_stmt_iterator *) { return false; }
112
113 bool substitute_and_fold (basic_block = NULL);
114 bool replace_uses_in (gimple *);
115 bool replace_phi_args_in (gphi *);
116
117 virtual void pre_fold_bb (basic_block) { }
118 virtual void post_fold_bb (basic_block) { }
119 virtual void pre_fold_stmt (gimple *) { }
120 virtual void post_new_stmt (gimple *) { }
121
122 bool propagate_into_phi_args (basic_block);
123
124 /* Users like VRP can set this when they want to perform
125 folding for every propagation. */
126 bool fold_all_stmts;
127};
128
129#endif /* _TREE_SSA_PROPAGATE_H */
130

source code of gcc/tree-ssa-propagate.h