gcc/tree-vector-builder.h

   1 /* A class for building vector tree constants.
   2    Copyright (C) 2017-2020 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 under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 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 #ifndef GCC_TREE_VECTOR_BUILDER_H
  21 #define GCC_TREE_VECTOR_BUILDER_H
  22
  23 #include "vector-builder.h"
  24
  25 /* This class is used to build VECTOR_CSTs from a sequence of elements.
  26    See vector_builder for more details.  */
  27 class tree_vector_builder : public vector_builder<tree, tree,
  28                                                   tree_vector_builder>
  29 {
  30   typedef vector_builder<tree, tree, tree_vector_builder> parent;
  31   friend class vector_builder<tree, tree, tree_vector_builder>;
  32
  33 public:
  34   tree_vector_builder () : m_type (0) {}
  35   tree_vector_builder (tree, unsigned int, unsigned int);
  36   tree build ();
  37
  38   tree type () const { return m_type; }
  39
  40   void new_vector (tree, unsigned int, unsigned int);
  41
  42 private:
  43   bool equal_p (const_tree, const_tree) const;
  44   bool allow_steps_p () const;
  45   bool integral_p (const_tree) const;
  46   wide_int step (const_tree, const_tree) const;
  47   tree apply_step (tree, unsigned int, const wide_int &) const;
  48   bool can_elide_p (const_tree) const;
  49   void note_representative (tree *, tree);
  50
  51   static poly_uint64 shape_nelts (const_tree t)
  52     { return TYPE_VECTOR_SUBPARTS (t); }
  53   static poly_uint64 nelts_of (const_tree t)
  54     { return VECTOR_CST_NELTS (t); }
  55   static unsigned int npatterns_of (const_tree t)
  56     { return VECTOR_CST_NPATTERNS (t); }
  57   static unsigned int nelts_per_pattern_of (const_tree t)
  58     { return VECTOR_CST_NELTS_PER_PATTERN (t); }
  59
  60   tree m_type;
  61 };
  62
  63 /* Create a new builder for a vector of type TYPE.  Initially encode the
  64    value as NPATTERNS interleaved patterns with NELTS_PER_PATTERN elements
  65    each.  */
  66
  67 inline
  68 tree_vector_builder::tree_vector_builder (tree type, unsigned int npatterns,
  69                                           unsigned int nelts_per_pattern)
  70 {
  71   new_vector (type, npatterns, nelts_per_pattern);
  72 }
  73
  74 /* Start building a new vector of type TYPE.  Initially encode the value
  75    as NPATTERNS interleaved patterns with NELTS_PER_PATTERN elements each.  */
  76
  77 inline void
  78 tree_vector_builder::new_vector (tree type, unsigned int npatterns,
  79                                  unsigned int nelts_per_pattern)
  80 {
  81   m_type = type;
  82   parent::new_vector (TYPE_VECTOR_SUBPARTS (type), npatterns,
  83                       nelts_per_pattern);
  84 }
  85
  86 /* Return true if elements I1 and I2 are equal.  */
  87
  88 inline bool
  89 tree_vector_builder::equal_p (const_tree elt1, const_tree elt2) const
  90 {
  91   return operand_equal_p (elt1, elt2, OEP_BITWISE);
  92 }
  93
  94 /* Return true if a stepped representation is OK.  We don't allow
  95    linear series for anything other than integers, to avoid problems
  96    with rounding.  */
  97
  98 inline bool
  99 tree_vector_builder::allow_steps_p () const
 100 {
 101   return INTEGRAL_TYPE_P (TREE_TYPE (m_type));
 102 }
 103
 104 /* Return true if ELT can be interpreted as an integer.  */
 105
 106 inline bool
 107 tree_vector_builder::integral_p (const_tree elt) const
 108 {
 109   return TREE_CODE (elt) == INTEGER_CST;
 110 }
 111
 112 /* Return the value of element ELT2 minus the value of element ELT1.
 113    Both elements are known to be INTEGER_CSTs.  */
 114
 115 inline wide_int
 116 tree_vector_builder::step (const_tree elt1, const_tree elt2) const
 117 {
 118   return wi::to_wide (elt2) - wi::to_wide (elt1);
 119 }
 120
 121 /* Return true if we can drop element ELT, even if the retained elements
 122    are different.  Return false if this would mean losing overflow
 123    information.  */
 124
 125 inline bool
 126 tree_vector_builder::can_elide_p (const_tree elt) const
 127 {
 128   return !CONSTANT_CLASS_P (elt) || !TREE_OVERFLOW (elt);
 129 }
 130
 131 /* Record that ELT2 is being elided, given that ELT1_PTR points to the last
 132    encoded element for the containing pattern.  */
 133
 134 inline void
 135 tree_vector_builder::note_representative (tree *elt1_ptr, tree elt2)
 136 {
 137   if (CONSTANT_CLASS_P (elt2) && TREE_OVERFLOW (elt2))
 138     {
 139       gcc_assert (operand_equal_p (*elt1_ptr, elt2, 0));
 140       if (!TREE_OVERFLOW (elt2))
 141         *elt1_ptr = elt2;
 142     }
 143 }
 144
 145 #endif