gcc/tree-affine.h

   1 /* Operations with affine combinations of trees.
   2    Copyright (C) 2005-2020 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 it
   7 under the terms of the GNU General Public License as published by the
   8 Free Software Foundation; either version 3, or (at your option) any
   9 later version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT
  12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 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 /* Affine combination of trees.  We keep track of at most MAX_AFF_ELTS elements
  21    to make things simpler; this is sufficient in most cases.  */
  22
  23 #ifndef GCC_TREE_AFFINE_H
  24 #define GCC_TREE_AFFINE_H
  25
  26
  27 #define MAX_AFF_ELTS 8
  28
  29 /* Element of an affine combination.  */
  30
  31 class aff_comb_elt
  32 {
  33 public:
  34   /* The value of the element.  */
  35   tree val;
  36
  37   /* Its coefficient in the combination.  */
  38   widest_int coef;
  39 };
  40
  41 class aff_tree
  42 {
  43 public:
  44   /* Type of the result of the combination.  */
  45   tree type;
  46
  47   /* Constant offset.  */
  48   poly_widest_int offset;
  49
  50   /* Number of elements of the combination.  */
  51   unsigned n;
  52
  53   /* Elements and their coefficients.  Type of elements may be different from
  54      TYPE, but their sizes must be the same (STRIP_NOPS is applied to the
  55      elements).
  56
  57      The coefficients are always sign extended from the precision of TYPE
  58      (regardless of signedness of TYPE).  */
  59   class aff_comb_elt elts[MAX_AFF_ELTS];
  60
  61   /* Remainder of the expression.  Usually NULL, used only if there are more
  62      than MAX_AFF_ELTS elements.  Type of REST will be either sizetype for
  63      TYPE of POINTER_TYPEs or TYPE.  */
  64   tree rest;
  65 };
  66
  67 class name_expansion;
  68
  69 void aff_combination_const (aff_tree *, tree, const poly_widest_int &);
  70 void aff_combination_elt (aff_tree *, tree, tree);
  71 void aff_combination_scale (aff_tree *, const widest_int &);
  72 void aff_combination_mult (aff_tree *, aff_tree *, aff_tree *);
  73 void aff_combination_add (aff_tree *, aff_tree *);
  74 void aff_combination_add_elt (aff_tree *, tree, const widest_int &);
  75 void aff_combination_remove_elt (aff_tree *, unsigned);
  76 void aff_combination_convert (aff_tree *, tree);
  77 void tree_to_aff_combination (tree, tree, aff_tree *);
  78 tree aff_combination_to_tree (aff_tree *);
  79 void unshare_aff_combination (aff_tree *);
  80 bool aff_combination_constant_multiple_p (aff_tree *, aff_tree *,
  81                                           poly_widest_int *);
  82 void aff_combination_expand (aff_tree *, hash_map<tree, name_expansion *> **);
  83 void tree_to_aff_combination_expand (tree, tree, aff_tree *,
  84                                      hash_map<tree, name_expansion *> **);
  85 tree get_inner_reference_aff (tree, aff_tree *, poly_widest_int *);
  86 void free_affine_expand_cache (hash_map<tree, name_expansion *> **);
  87 bool aff_comb_cannot_overlap_p (aff_tree *, const poly_widest_int &,
  88                                 const poly_widest_int &);
  89
  90 /* Debugging functions.  */
  91 void debug_aff (aff_tree *);
  92
  93 /* Return AFF's type.  */
  94 inline tree
  95 aff_combination_type (aff_tree *aff)
  96 {
  97   return aff->type;
  98 }
  99
 100 /* Return true if AFF is actually ZERO.  */
 101 inline bool
 102 aff_combination_zero_p (aff_tree *aff)
 103 {
 104   if (!aff)
 105     return true;
 106
 107   if (aff->n == 0 && known_eq (aff->offset, 0))
 108     return true;
 109
 110   return false;
 111 }
 112
 113 /* Return true if AFF is actually const.  */
 114 inline bool
 115 aff_combination_const_p (aff_tree *aff)
 116 {
 117   return (aff == NULL || aff->n == 0);
 118 }
 119
 120 /* Return true iff AFF contains one (negated) singleton variable.  Users need
 121    to make sure AFF points to a valid combination.  */
 122 inline bool
 123 aff_combination_singleton_var_p (aff_tree *aff)
 124 {
 125   return (aff->n == 1
 126           && known_eq (aff->offset, 0)
 127           && (aff->elts[0].coef == 1 || aff->elts[0].coef == -1));
 128 }
 129 #endif /* GCC_TREE_AFFINE_H */