1  /* A class for building vector tree constants.
       2     Copyright (C) 2017-2023 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