GCC Middle and Back End API Reference
tree-ssa-propagate.h
Go to the documentation of this file.
1 /* Data structures and function declarations for the SSA value propagation
2  engine.
3  Copyright (C) 2004-2013 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 /* Call-back functions used by the value propagation engine. */
65 typedef enum ssa_prop_result (*ssa_prop_visit_stmt_fn) (gimple, edge *, tree *);
66 typedef enum ssa_prop_result (*ssa_prop_visit_phi_fn) (gimple);
67 typedef bool (*ssa_prop_fold_stmt_fn) (gimple_stmt_iterator *gsi);
68 typedef tree (*ssa_prop_get_value_fn) (tree);
69 
70 
71 extern bool valid_gimple_rhs_p (tree);
72 extern void move_ssa_defining_stmt_for_defs (gimple, gimple);
73 extern bool update_gimple_call (gimple_stmt_iterator *, tree, int, ...);
74 extern bool update_call_from_tree (gimple_stmt_iterator *, tree);
75 extern void ssa_propagate (ssa_prop_visit_stmt_fn, ssa_prop_visit_phi_fn);
76 extern bool stmt_makes_single_store (gimple);
77 extern bool substitute_and_fold (ssa_prop_get_value_fn, ssa_prop_fold_stmt_fn,
78  bool);
79 extern bool may_propagate_copy (tree, tree);
80 extern bool may_propagate_copy_into_stmt (gimple, tree);
81 extern bool may_propagate_copy_into_asm (tree);
82 extern void propagate_value (use_operand_p, tree);
83 extern void replace_exp (use_operand_p, tree);
84 extern void propagate_tree_value (tree *, tree);
85 extern void propagate_tree_value_into_stmt (gimple_stmt_iterator *, tree);
86 
87 #endif /* _TREE_SSA_PROPAGATE_H */