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author kent <kent@cr.ie.u-ryukyu.ac.jp>
date Fri, 17 Jul 2009 14:47:48 +0900
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1 /* Data structures and function declarations for the SSA value propagation
2 engine.
3 Copyright (C) 2004, 2005, 2007, 2008 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 struct prop_value_d {
65 /* Lattice value. Each propagator is free to define its own
66 lattice and this field is only meaningful while propagating.
67 It will not be used by substitute_and_fold. */
68 unsigned lattice_val;
69
70 /* Propagated value. */
71 tree value;
72 };
73
74 typedef struct prop_value_d prop_value_t;
75
76
77 /* Type of value ranges. See value_range_d for a description of these
78 types. */
79 enum value_range_type { VR_UNDEFINED, VR_RANGE, VR_ANTI_RANGE, VR_VARYING };
80
81 /* Range of values that can be associated with an SSA_NAME after VRP
82 has executed. */
83 struct value_range_d
84 {
85 /* Lattice value represented by this range. */
86 enum value_range_type type;
87
88 /* Minimum and maximum values represented by this range. These
89 values should be interpreted as follows:
90
91 - If TYPE is VR_UNDEFINED or VR_VARYING then MIN and MAX must
92 be NULL.
93
94 - If TYPE == VR_RANGE then MIN holds the minimum value and
95 MAX holds the maximum value of the range [MIN, MAX].
96
97 - If TYPE == ANTI_RANGE the variable is known to NOT
98 take any values in the range [MIN, MAX]. */
99 tree min;
100 tree max;
101
102 /* Set of SSA names whose value ranges are equivalent to this one.
103 This set is only valid when TYPE is VR_RANGE or VR_ANTI_RANGE. */
104 bitmap equiv;
105 };
106
107 typedef struct value_range_d value_range_t;
108
109
110 /* Call-back functions used by the value propagation engine. */
111 typedef enum ssa_prop_result (*ssa_prop_visit_stmt_fn) (gimple, edge *, tree *);
112 typedef enum ssa_prop_result (*ssa_prop_visit_phi_fn) (gimple);
113
114
115 /* In tree-ssa-propagate.c */
116 void ssa_propagate (ssa_prop_visit_stmt_fn, ssa_prop_visit_phi_fn);
117 bool valid_gimple_rhs_p (tree);
118 bool valid_gimple_call_p (tree);
119 void move_ssa_defining_stmt_for_defs (gimple, gimple);
120 bool update_call_from_tree (gimple_stmt_iterator *, tree);
121 bool stmt_makes_single_load (gimple);
122 bool stmt_makes_single_store (gimple);
123 bool substitute_and_fold (prop_value_t *, bool);
124
125 #endif /* _TREE_SSA_PROPAGATE_H */