1/* Header file for jump threading path solver.
2 Copyright (C) 2021-2023 Free Software Foundation, Inc.
3 Contributed by Aldy Hernandez <aldyh@redhat.com>.
4
5This file is part of GCC.
6
7GCC is free software; you can redistribute it and/or modify it under
8the terms of the GNU General Public License as published by the Free
9Software Foundation; either version 3, or (at your option) any later
10version.
11
12GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13WARRANTY; without even the implied warranty of MERCHANTABILITY or
14FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 for more details.
16
17You should have received a copy of the GNU General Public License
18along with GCC; see the file COPYING3. If not see
19<http://www.gnu.org/licenses/>. */
20
21#ifndef GCC_TREE_SSA_THREADSOLVER_H
22#define GCC_TREE_SSA_THREADSOLVER_H
23
24// This class is a basic block path solver. Given a set of BBs
25// indicating a path through the CFG, range_of_expr and range_of_stmt
26// will calculate the range of an SSA or STMT as if the BBs in the
27// path would have been executed in order.
28//
29// Note that the blocks are in reverse order, thus the exit block is
30// path[0].
31
32class path_range_query : public range_query
33{
34public:
35 path_range_query (class gimple_ranger &ranger,
36 const vec<basic_block> &path,
37 const bitmap_head *dependencies = NULL,
38 bool resolve = true);
39 path_range_query (gimple_ranger &ranger, bool resolve = true);
40 virtual ~path_range_query ();
41 void reset_path (const vec<basic_block> &, const bitmap_head *dependencies);
42 bool range_of_expr (vrange &r, tree name, gimple * = NULL) override;
43 bool range_of_stmt (vrange &r, gimple *, tree name = NULL) override;
44 bool unreachable_path_p ();
45 void dump (FILE *) override;
46 void debug ();
47
48private:
49 bool internal_range_of_expr (vrange &r, tree name, gimple *);
50 void compute_ranges (const bitmap_head *dependencies);
51 void compute_exit_dependencies (bitmap_head *dependencies);
52 bool defined_outside_path (tree name);
53 void range_on_path_entry (vrange &r, tree name);
54 path_oracle *get_path_oracle () { return (path_oracle *)m_oracle; }
55
56 // Cache manipulation.
57 bool get_cache (vrange &r, tree name);
58
59 // Methods to compute ranges for the given path.
60 bool range_defined_in_block (vrange &, tree name, basic_block bb);
61 void compute_ranges_in_block (basic_block bb);
62 void compute_ranges_in_phis (basic_block bb);
63 void adjust_for_non_null_uses (basic_block bb);
64 void ssa_range_in_phi (vrange &r, gphi *phi);
65 void compute_outgoing_relations (basic_block bb, basic_block next);
66 void compute_phi_relations (basic_block bb, basic_block prev);
67 void maybe_register_phi_relation (gphi *, edge e);
68 bool add_to_exit_dependencies (tree name, bitmap dependencies);
69 bool exit_dependency_p (tree name);
70 bool ssa_defined_in_bb (tree name, basic_block bb);
71 bool relations_may_be_invalidated (edge);
72
73 // Path navigation.
74 basic_block entry_bb () { return m_path[m_path.length () - 1]; }
75 basic_block exit_bb () { return m_path[0]; }
76 basic_block curr_bb () { return m_path[m_pos]; }
77 basic_block prev_bb () { return m_path[m_pos + 1]; }
78 basic_block next_bb () { return m_path[m_pos - 1]; }
79 bool at_entry () { return m_pos == m_path.length () - 1; }
80 bool at_exit () { return m_pos == 0; }
81 void move_next () { --m_pos; }
82
83 // Range cache for SSA names.
84 ssa_lazy_cache m_cache;
85
86 // Path being analyzed.
87 auto_vec<basic_block> m_path;
88
89 // This is a list of SSA names that may have relevant context
90 // information for solving the final conditional along the path.
91 // Ranges for these SSA names are pre-calculated and cached during a
92 // top-down traversal of the path, and are then used to answer
93 // questions at the path exit.
94 auto_bitmap m_exit_dependencies;
95
96 // A ranger used to resolve ranges for SSA names whose values come
97 // from outside the path.
98 gimple_ranger &m_ranger;
99
100 // Current path position.
101 unsigned m_pos;
102
103 // Use ranger to resolve anything not known on entry.
104 bool m_resolve;
105
106 // Set if there were any undefined expressions while pre-calculating path.
107 bool m_undefined_path;
108};
109
110#endif // GCC_TREE_SSA_THREADSOLVER_H
111

source code of gcc/gimple-range-path.h