1 /* Data structures and function declarations for the SSA value propagation
2 engine.
3 Copyright (C) 2004-2021 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
prop_set_simulate_again(gimple * s,bool visit_p)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
prop_simulate_again_p(gimple * s)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 bool valid_gimple_rhs_p (tree);
67 extern void move_ssa_defining_stmt_for_defs (gimple *, gimple *);
68 extern bool update_gimple_call (gimple_stmt_iterator *, tree, int, ...);
69 extern bool update_call_from_tree (gimple_stmt_iterator *, tree);
70 extern bool stmt_makes_single_store (gimple *);
71 extern bool may_propagate_copy (tree, tree);
72 extern bool may_propagate_copy_into_stmt (gimple *, tree);
73 extern bool may_propagate_copy_into_asm (tree);
74 extern void propagate_value (use_operand_p, tree);
75 extern void replace_exp (use_operand_p, tree);
76 extern void propagate_tree_value (tree *, tree);
77 extern void propagate_tree_value_into_stmt (gimple_stmt_iterator *, tree);
78
79 /* Public interface into the SSA propagation engine. Clients should inherit
80 from this class and provide their own visitors. */
81
82 class ssa_propagation_engine
83 {
84 public:
85
~ssa_propagation_engine(void)86 virtual ~ssa_propagation_engine (void) { }
87
88 /* Virtual functions the clients must provide to visit statements
89 and phi nodes respectively. */
90 virtual enum ssa_prop_result visit_stmt (gimple *, edge *, tree *) = 0;
91 virtual enum ssa_prop_result visit_phi (gphi *) = 0;
92
93 /* Main interface into the propagation engine. */
94 void ssa_propagate (void);
95
96 private:
97 /* Internal implementation details. */
98 void simulate_stmt (gimple *stmt);
99 void simulate_block (basic_block);
100 };
101
102 class substitute_and_fold_engine : public value_query
103 {
104 public:
105 substitute_and_fold_engine (bool fold_all_stmts = false)
fold_all_stmts(fold_all_stmts)106 : fold_all_stmts (fold_all_stmts) { }
~substitute_and_fold_engine(void)107 virtual ~substitute_and_fold_engine (void) { }
fold_stmt(gimple_stmt_iterator *)108 virtual bool fold_stmt (gimple_stmt_iterator *) { return false; }
109
110 bool substitute_and_fold (basic_block = NULL);
111 bool replace_uses_in (gimple *);
112 bool replace_phi_args_in (gphi *);
113
pre_fold_bb(basic_block)114 virtual void pre_fold_bb (basic_block) { }
post_fold_bb(basic_block)115 virtual void post_fold_bb (basic_block) { }
pre_fold_stmt(gimple *)116 virtual void pre_fold_stmt (gimple *) { }
post_new_stmt(gimple *)117 virtual void post_new_stmt (gimple *) { }
118
119 bool propagate_into_phi_args (basic_block);
120
121 /* Users like VRP can set this when they want to perform
122 folding for every propagation. */
123 bool fold_all_stmts;
124 };
125
126 #endif /* _TREE_SSA_PROPAGATE_H */
127