1/* Data structures and function declarations for the SSA value propagation
2 engine.
3 Copyright (C) 2004-2017 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/* If SIM_P is true, statement S will be simulated again. */
26
27static inline void
28prop_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
35static inline bool
36prop_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. */
44enum 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
64extern bool valid_gimple_rhs_p (tree);
65extern void move_ssa_defining_stmt_for_defs (gimple *, gimple *);
66extern bool update_gimple_call (gimple_stmt_iterator *, tree, int, ...);
67extern bool update_call_from_tree (gimple_stmt_iterator *, tree);
68extern bool stmt_makes_single_store (gimple *);
69extern bool may_propagate_copy (tree, tree);
70extern bool may_propagate_copy_into_stmt (gimple *, tree);
71extern bool may_propagate_copy_into_asm (tree);
72extern void propagate_value (use_operand_p, tree);
73extern void replace_exp (use_operand_p, tree);
74extern void propagate_tree_value (tree *, tree);
75extern 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
80class 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 process_ssa_edge_worklist (void);
98 void simulate_block (basic_block);
99
100};
101
102class substitute_and_fold_engine
103{
104 public:
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 (void);
110 bool replace_uses_in (gimple *);
111 bool replace_phi_args_in (gphi *);
112};
113
114#endif /* _TREE_SSA_PROPAGATE_H */
115