gcc/tree-affine.h

   1 /* Operations with affine combinations of trees.
   2    Copyright (C) 2005-2018 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 struct aff_comb_elt
  32 {
  33   /* The value of the element.  */
  34   tree val;
  35
  36   /* Its coefficient in the combination.  */
  37   widest_int coef;
  38 };
  39
  40 struct aff_tree
  41 {
  42   /* Type of the result of the combination.  */
  43   tree type;
  44
  45   /* Constant offset.  */
  46   poly_widest_int offset;
  47
  48   /* Number of elements of the combination.  */
  49   unsigned n;
  50
  51   /* Elements and their coefficients.  Type of elements may be different from
  52      TYPE, but their sizes must be the same (STRIP_NOPS is applied to the
  53      elements).
  54
  55      The coefficients are always sign extended from the precision of TYPE
  56      (regardless of signedness of TYPE).  */
  57   struct aff_comb_elt elts[MAX_AFF_ELTS];
  58
  59   /* Remainder of the expression.  Usually NULL, used only if there are more
  60      than MAX_AFF_ELTS elements.  Type of REST will be either sizetype for
  61      TYPE of POINTER_TYPEs or TYPE.  */
  62   tree rest;
  63 };
  64
  65 struct name_expansion;
  66
  67 void aff_combination_const (aff_tree *, tree, const poly_widest_int &);
  68 void aff_combination_elt (aff_tree *, tree, tree);
  69 void aff_combination_scale (aff_tree *, const widest_int &);
  70 void aff_combination_mult (aff_tree *, aff_tree *, aff_tree *);
  71 void aff_combination_add (aff_tree *, aff_tree *);
  72 void aff_combination_add_elt (aff_tree *, tree, const widest_int &);
  73 void aff_combination_remove_elt (aff_tree *, unsigned);
  74 void aff_combination_convert (aff_tree *, tree);
  75 void tree_to_aff_combination (tree, tree, aff_tree *);
  76 tree aff_combination_to_tree (aff_tree *);
  77 void unshare_aff_combination (aff_tree *);
  78 bool aff_combination_constant_multiple_p (aff_tree *, aff_tree *,
  79                                           poly_widest_int *);
  80 void aff_combination_expand (aff_tree *, hash_map<tree, name_expansion *> **);
  81 void tree_to_aff_combination_expand (tree, tree, aff_tree *,
  82                                      hash_map<tree, name_expansion *> **);
  83 tree get_inner_reference_aff (tree, aff_tree *, poly_widest_int *);
  84 void free_affine_expand_cache (hash_map<tree, name_expansion *> **);
  85 bool aff_comb_cannot_overlap_p (aff_tree *, const poly_widest_int &,
  86                                 const poly_widest_int &);
  87
  88 /* Debugging functions.  */
  89 void debug_aff (aff_tree *);
  90
  91 /* Return AFF's type.  */
  92 inline tree
  93 aff_combination_type (aff_tree *aff)
  94 {
  95   return aff->type;
  96 }
  97
  98 /* Return true if AFF is actually ZERO.  */
  99 inline bool
 100 aff_combination_zero_p (aff_tree *aff)
 101 {
 102   if (!aff)
 103     return true;
 104
 105   if (aff->n == 0 && known_eq (aff->offset, 0))
 106     return true;
 107
 108   return false;
 109 }
 110
 111 /* Return true if AFF is actually const.  */
 112 inline bool
 113 aff_combination_const_p (aff_tree *aff)
 114 {
 115   return (aff == NULL || aff->n == 0);
 116 }
 117
 118 /* Return true iff AFF contains one (negated) singleton variable.  Users need
 119    to make sure AFF points to a valid combination.  */
 120 inline bool
 121 aff_combination_singleton_var_p (aff_tree *aff)
 122 {
 123   return (aff->n == 1
 124           && known_eq (aff->offset, 0)
 125           && (aff->elts[0].coef == 1 || aff->elts[0].coef == -1));
 126 }
 127 #endif /* GCC_TREE_AFFINE_H */