1 /* Support routines for Value Range Propagation (VRP). 2 Copyright (C) 2016-2020 Free Software Foundation, Inc. 3 4 This file is part of GCC. 5 6 GCC is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 3, or (at your option) 9 any later version. 10 11 GCC is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along 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. */ 37 class vr_values 38 { 39 public: 40 vr_values (void); 41 ~vr_values (void); 42 43 const value_range_equiv *get_value_range (const_tree); 44 void set_vr_value (tree, value_range_equiv *); 45 value_range_equiv *swap_vr_value (tree, value_range_equiv *); 46 47 void set_def_to_varying (const_tree); 48 void set_defs_to_varying (gimple *); 49 bool update_value_range (const_tree, value_range_equiv *); 50 tree op_with_constant_singleton_value_range (tree); 51 void adjust_range_with_scev (value_range_equiv *, class loop *, 52 gimple *, tree); 53 tree vrp_evaluate_conditional (tree_code, tree, tree, gimple *); 54 void dump_all_value_ranges (FILE *); 55 56 void extract_range_for_var_from_comparison_expr (tree, enum tree_code, 57 tree, tree, 58 value_range_equiv *); 59 void extract_range_from_phi_node (gphi *, value_range_equiv *); 60 void extract_range_basic (value_range_equiv *, gimple *); 61 void extract_range_from_stmt (gimple *, edge *, tree *, value_range_equiv *); 62 63 void vrp_visit_cond_stmt (gcond *, edge *); 64 65 void simplify_cond_using_ranges_2 (gcond *); 66 bool simplify_stmt_using_ranges (gimple_stmt_iterator *); 67 68 /* Indicate that propagation through the lattice is complete. */ 69 void set_lattice_propagation_complete (void) { values_propagated = true; } 70 71 /* Allocate a new value_range object. */ 72 value_range_equiv *allocate_value_range_equiv (void) 73 { return vrp_value_range_pool.allocate (); } 74 void free_value_range (value_range_equiv *vr) 75 { vrp_value_range_pool.remove (vr); } 76 77 /* */ 78 void cleanup_edges_and_switches (void); 79 80 private: 81 value_range_equiv *get_lattice_entry (const_tree); 82 bool vrp_stmt_computes_nonzero (gimple *); 83 bool op_with_boolean_value_range_p (tree); 84 bool check_for_binary_op_overflow (enum tree_code, tree, tree, tree, bool *); 85 const value_range_equiv *get_vr_for_comparison (int, value_range_equiv *); 86 tree compare_name_with_value (enum tree_code, tree, tree, bool *, bool); 87 tree compare_names (enum tree_code, tree, tree, bool *); 88 bool two_valued_val_range_p (tree, tree *, tree *); 89 tree vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code, 90 tree, tree, 91 bool *); 92 tree vrp_evaluate_conditional_warnv_with_ops (enum tree_code, 93 tree, tree, bool, 94 bool *, bool *); 95 void extract_range_from_assignment (value_range_equiv *, gassign *); 96 void extract_range_from_assert (value_range_equiv *, tree); 97 void extract_range_from_ssa_name (value_range_equiv *, tree); 98 void extract_range_from_binary_expr (value_range_equiv *, enum tree_code, 99 tree, tree, tree); 100 void extract_range_from_unary_expr (value_range_equiv *, enum tree_code, 101 tree, tree); 102 void extract_range_from_cond_expr (value_range_equiv *, gassign *); 103 void extract_range_from_comparison (value_range_equiv *, enum tree_code, 104 tree, tree, tree); 105 void vrp_visit_assignment_or_call (gimple*, tree *, value_range_equiv *); 106 void vrp_visit_switch_stmt (gswitch *, edge *); 107 bool simplify_truth_ops_using_ranges (gimple_stmt_iterator *, gimple *); 108 bool simplify_div_or_mod_using_ranges (gimple_stmt_iterator *, gimple *); 109 bool simplify_abs_using_ranges (gimple_stmt_iterator *, gimple *); 110 bool simplify_bit_ops_using_ranges (gimple_stmt_iterator *, gimple *); 111 bool simplify_min_or_max_using_ranges (gimple_stmt_iterator *, gimple *); 112 bool simplify_cond_using_ranges_1 (gcond *); 113 bool simplify_switch_using_ranges (gswitch *); 114 bool simplify_float_conversion_using_ranges (gimple_stmt_iterator *, 115 gimple *); 116 bool simplify_internal_call_using_ranges (gimple_stmt_iterator *, gimple *); 117 118 /* Allocation pools for value_range objects. */ 119 object_allocator<value_range_equiv> vrp_value_range_pool; 120 121 /* This probably belongs in the lattice rather than in here. */ 122 bool values_propagated; 123 124 /* Allocations for equivalences all come from this obstack. */ 125 bitmap_obstack vrp_equiv_obstack; 126 127 /* Value range array. After propagation, VR_VALUE[I] holds the range 128 of values that SSA name N_I may take. */ 129 unsigned int num_vr_values; 130 value_range_equiv **vr_value; 131 132 /* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the 133 number of executable edges we saw the last time we visited the 134 node. */ 135 int *vr_phi_edge_counts; 136 137 /* Vectors of edges that need removing and switch statements that 138 need updating. It is expected that a pass using the simplification 139 routines will, at the end of the pass, clean up the edges and 140 switch statements. The class dtor will try to detect cases 141 that do not follow that expectation. */ 142 struct switch_update { 143 gswitch *stmt; 144 tree vec; 145 }; 146 147 vec<edge> to_remove_edges; 148 vec<switch_update> to_update_switch_stmts; 149 }; 150 151 extern tree get_output_for_vrp (gimple *); 152 #endif /* GCC_VR_VALUES_H */ 153