gcc/vr-values.h

   1 /* Support routines for Value Range Propagation (VRP).
   2    Copyright (C) 2016-2017 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   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
 131 extern tree get_output_for_vrp (gimple *);
 132 #endif /* GCC_VR_VALUES_H */