gcc/tree-vector-builder.h

   1 /* A class for building vector tree constants.
   2    Copyright (C) 2017-2018 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 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_vector_builder>
  28 {
  29   typedef vector_builder<tree, tree_vector_builder> parent;
  30   friend class vector_builder<tree, tree_vector_builder>;
  31
  32 public:
  33   tree_vector_builder () : m_type (0) {}
  34   tree_vector_builder (tree, unsigned int, unsigned int);
  35   tree build ();
  36
  37   tree type () const { return m_type; }
  38
  39   void new_vector (tree, unsigned int, unsigned int);
  40   bool new_unary_operation (tree, tree, bool);
  41   bool new_binary_operation (tree, tree, tree, bool);
  42
  43   static unsigned int binary_encoded_nelts (tree, tree);
  44
  45 private:
  46   bool equal_p (const_tree, const_tree) const;
  47   bool allow_steps_p () const;
  48   bool integral_p (const_tree) const;
  49   wide_int step (const_tree, const_tree) const;
  50   tree apply_step (tree, unsigned int, const wide_int &) const;
  51   bool can_elide_p (const_tree) const;
  52   void note_representative (tree *, tree);
  53
  54   tree m_type;
  55 };
  56
  57 /* Create a new builder for a vector of type TYPE.  Initially encode the
  58    value as NPATTERNS interleaved patterns with NELTS_PER_PATTERN elements
  59    each.  */
  60
  61 inline
  62 tree_vector_builder::tree_vector_builder (tree type, unsigned int npatterns,
  63                                           unsigned int nelts_per_pattern)
  64 {
  65   new_vector (type, npatterns, nelts_per_pattern);
  66 }
  67
  68 /* Start building a new vector of type TYPE.  Initially encode the value
  69    as NPATTERNS interleaved patterns with NELTS_PER_PATTERN elements each.  */
  70
  71 inline void
  72 tree_vector_builder::new_vector (tree type, unsigned int npatterns,
  73                                  unsigned int nelts_per_pattern)
  74 {
  75   m_type = type;
  76   parent::new_vector (TYPE_VECTOR_SUBPARTS (type), npatterns,
  77                       nelts_per_pattern);
  78 }
  79
  80 /* Return true if elements I1 and I2 are equal.  */
  81
  82 inline bool
  83 tree_vector_builder::equal_p (const_tree elt1, const_tree elt2) const
  84 {
  85   return operand_equal_p (elt1, elt2, 0);
  86 }
  87
  88 /* Return true if a stepped representation is OK.  We don't allow
  89    linear series for anything other than integers, to avoid problems
  90    with rounding.  */
  91
  92 inline bool
  93 tree_vector_builder::allow_steps_p () const
  94 {
  95   return INTEGRAL_TYPE_P (TREE_TYPE (m_type));
  96 }
  97
  98 /* Return true if ELT can be interpreted as an integer.  */
  99
 100 inline bool
 101 tree_vector_builder::integral_p (const_tree elt) const
 102 {
 103   return TREE_CODE (elt) == INTEGER_CST;
 104 }
 105
 106 /* Return the value of element ELT2 minus the value of element ELT1.
 107    Both elements are known to be INTEGER_CSTs.  */
 108
 109 inline wide_int
 110 tree_vector_builder::step (const_tree elt1, const_tree elt2) const
 111 {
 112   return wi::to_wide (elt2) - wi::to_wide (elt1);
 113 }
 114
 115 /* Return true if we can drop element ELT, even if the retained elements
 116    are different.  Return false if this would mean losing overflow
 117    information.  */
 118
 119 inline bool
 120 tree_vector_builder::can_elide_p (const_tree elt) const
 121 {
 122   return !CONSTANT_CLASS_P (elt) || !TREE_OVERFLOW (elt);
 123 }
 124
 125 /* Record that ELT2 is being elided, given that ELT1_PTR points to the last
 126    encoded element for the containing pattern.  */
 127
 128 inline void
 129 tree_vector_builder::note_representative (tree *elt1_ptr, tree elt2)
 130 {
 131   if (CONSTANT_CLASS_P (elt2) && TREE_OVERFLOW (elt2))
 132     {
 133       gcc_assert (operand_equal_p (*elt1_ptr, elt2, 0));
 134       if (!TREE_OVERFLOW (elt2))
 135         *elt1_ptr = elt2;
 136     }
 137 }
 138
 139 #endif