1/* Support routines for Value Range Propagation (VRP).
2 Copyright (C) 2016-2017 Free Software Foundation, Inc.
3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify
7it under the terms of the GNU General Public License as published by
8the Free Software Foundation; either version 3, or (at your option)
9any later version.
10
11GCC is distributed in the hope that it will be useful,
12but WITHOUT ANY WARRANTY; without even the implied warranty of
13MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14GNU General Public License for more details.
15
16You should have received a copy of the GNU General Public License
17along with GCC; see the file COPYING3. If not see
18<http://www.gnu.org/licenses/>. */
19
20#ifndef GCC_VR_VALUES_H
21#define GCC_VR_VALUES_H
22
23/* The VR_VALUES class holds the current view of range information
24 for all the SSA_NAMEs in the IL.
25
26 It can be used to hold context sensitive range information during
27 a dominator walk or it may be used to hold range information in the
28 standard VRP pass as ranges are propagated through the lattice to a
29 steady state.
30
31 This information is independent of the range information that gets
32 attached to SSA_NAMEs. A pass such as VRP may choose to transfer
33 the global information it produces into global range information that
34 gets attached to an SSA_NAME. It's unclear how useful that global
35 information will be in a world where we can compute context sensitive
36 range information fast or perform on-demand queries. */
37class vr_values
38{
39 public:
40 vr_values (void);
41 ~vr_values (void);
42
43 value_range *get_value_range (const_tree);
44
45 void set_vr_value (tree, value_range *);
46 void set_defs_to_varying (gimple *);
47 bool update_value_range (const_tree, value_range *);
48 tree op_with_constant_singleton_value_range (tree);
49 void adjust_range_with_scev (value_range *, struct loop *, gimple *, tree);
50 tree vrp_evaluate_conditional (tree_code, tree, tree, gimple *);
51 void dump_all_value_ranges (FILE *);
52
53 void extract_range_for_var_from_comparison_expr (tree, enum tree_code,
54 tree, tree, value_range *);
55 void extract_range_from_phi_node (gphi *, value_range *);
56 void extract_range_basic (value_range *, gimple *);
57 void extract_range_from_stmt (gimple *, edge *, tree *, value_range *);
58
59 void vrp_visit_cond_stmt (gcond *, edge *);
60
61 void simplify_cond_using_ranges_2 (gcond *);
62 bool simplify_stmt_using_ranges (gimple_stmt_iterator *);
63
64 /* Indicate that propagation through the lattice is complete. */
65 void set_lattice_propagation_complete (void) { values_propagated = true; }
66
67 /* Allocate a new value_range object. */
68 value_range *allocate_value_range (void)
69 { return vrp_value_range_pool.allocate (); }
70
71 private:
72 void add_equivalence (bitmap *, const_tree);
73 bool vrp_stmt_computes_nonzero (gimple *);
74 bool op_with_boolean_value_range_p (tree);
75 bool check_for_binary_op_overflow (enum tree_code, tree, tree, tree, bool *);
76 value_range get_vr_for_comparison (int);
77 tree compare_name_with_value (enum tree_code, tree, tree, bool *, bool);
78 tree compare_names (enum tree_code, tree, tree, bool *);
79 bool two_valued_val_range_p (tree, tree *, tree *);
80 tree vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code,
81 tree, tree,
82 bool *);
83 tree vrp_evaluate_conditional_warnv_with_ops (enum tree_code,
84 tree, tree, bool,
85 bool *, bool *);
86 void extract_range_from_assignment (value_range *, gassign *);
87 void extract_range_from_assert (value_range *, tree);
88 void extract_range_from_ssa_name (value_range *, tree);
89 void extract_range_from_binary_expr (value_range *, enum tree_code,
90 tree, tree, tree);
91 void extract_range_from_unary_expr (value_range *, enum tree_code,
92 tree, tree);
93 void extract_range_from_cond_expr (value_range *, gassign *);
94 void extract_range_from_comparison (value_range *, enum tree_code,
95 tree, tree, tree);
96 void vrp_visit_assignment_or_call (gimple*, tree *, value_range *);
97 void vrp_visit_switch_stmt (gswitch *, edge *);
98 bool simplify_truth_ops_using_ranges (gimple_stmt_iterator *, gimple *);
99 bool simplify_div_or_mod_using_ranges (gimple_stmt_iterator *, gimple *);
100 bool simplify_abs_using_ranges (gimple_stmt_iterator *, gimple *);
101 bool simplify_bit_ops_using_ranges (gimple_stmt_iterator *, gimple *);
102 bool simplify_min_or_max_using_ranges (gimple_stmt_iterator *, gimple *);
103 bool simplify_cond_using_ranges_1 (gcond *);
104 bool simplify_switch_using_ranges (gswitch *);
105 bool simplify_float_conversion_using_ranges (gimple_stmt_iterator *,
106 gimple *);
107 bool simplify_internal_call_using_ranges (gimple_stmt_iterator *, gimple *);
108
109 /* Allocation pools for value_range objects. */
110 object_allocator<value_range> vrp_value_range_pool;
111
112 /* This probably belongs in the lattice rather than in here. */
113 bool values_propagated;
114
115 /* Allocations for equivalences all come from this obstack. */
116 bitmap_obstack vrp_equiv_obstack;
117
118 /* Value range array. After propagation, VR_VALUE[I] holds the range
119 of values that SSA name N_I may take. */
120 unsigned int num_vr_values;
121 value_range **vr_value;
122
123 /* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the
124 number of executable edges we saw the last time we visited the
125 node. */
126 int *vr_phi_edge_counts;
127};
128
129#define VR_INITIALIZER { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL }
130
131extern tree get_output_for_vrp (gimple *);
132#endif /* GCC_VR_VALUES_H */
133