gcc/rtx-vector-builder.c

   1 /* A class for building vector rtx 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 #include "config.h"
  21 #include "system.h"
  22 #include "coretypes.h"
  23 #include "tm.h"
  24 #include "rtl.h"
  25 #include "rtx-vector-builder.h"
  26
  27 /* Return a CONST_VECTOR for the current constant.  V is an existing
  28    rtvec that contains all the elements.  */
  29
  30 rtx
  31 rtx_vector_builder::build (rtvec v)
  32 {
  33   finalize ();
  34
  35   rtx x = find_cached_value ();
  36   if (x)
  37     return x;
  38
  39   x = gen_rtx_raw_CONST_VECTOR (m_mode, v);
  40   CONST_VECTOR_NPATTERNS (x) = npatterns ();
  41   CONST_VECTOR_NELTS_PER_PATTERN (x) = nelts_per_pattern ();
  42   return x;
  43 }
  44
  45 /* Return a vector element with the value BASE + FACTOR * STEP.  */
  46
  47 rtx
  48 rtx_vector_builder::apply_step (rtx base, unsigned int factor,
  49                                 const wide_int &step) const
  50 {
  51   scalar_int_mode int_mode = as_a <scalar_int_mode> (GET_MODE_INNER (m_mode));
  52   return immed_wide_int_const (wi::add (rtx_mode_t (base, int_mode),
  53                                         factor * step),
  54                                int_mode);
  55 }
  56
  57 /* Return a CONST_VECTOR for the current constant.  */
  58
  59 rtx
  60 rtx_vector_builder::build ()
  61 {
  62   finalize ();
  63
  64   rtx x = find_cached_value ();
  65   if (x)
  66     return x;
  67
  68   unsigned int nelts;
  69   if (!GET_MODE_NUNITS (m_mode).is_constant (&nelts))
  70     nelts = encoded_nelts ();
  71   rtvec v = rtvec_alloc (nelts);
  72   for (unsigned int i = 0; i < nelts; ++i)
  73     RTVEC_ELT (v, i) = elt (i);
  74   x = gen_rtx_raw_CONST_VECTOR (m_mode, v);
  75   CONST_VECTOR_NPATTERNS (x) = npatterns ();
  76   CONST_VECTOR_NELTS_PER_PATTERN (x) = nelts_per_pattern ();
  77   return x;
  78 }
  79
  80 /* Check whether there is a global cached value for the vector.
  81    Return it if so, otherwise return null.  */
  82
  83 rtx
  84 rtx_vector_builder::find_cached_value ()
  85 {
  86   if (encoded_nelts () != 1)
  87     return NULL_RTX;
  88
  89   rtx elt = (*this)[0];
  90
  91   if (GET_MODE_CLASS (m_mode) == MODE_VECTOR_BOOL)
  92     {
  93       if (elt == const1_rtx || elt == constm1_rtx)
  94         return CONST1_RTX (m_mode);
  95       else if (elt == const0_rtx)
  96         return CONST0_RTX (m_mode);
  97       else
  98         gcc_unreachable ();
  99     }
 100
 101   /* We can be called before the global vector constants are set up,
 102      but in that case we'll just return null.  */
 103   scalar_mode inner_mode = GET_MODE_INNER (m_mode);
 104   if (elt == CONST0_RTX (inner_mode))
 105     return CONST0_RTX (m_mode);
 106   else if (elt == CONST1_RTX (inner_mode))
 107     return CONST1_RTX (m_mode);
 108   else if (elt == CONSTM1_RTX (inner_mode))
 109     return CONSTM1_RTX (m_mode);
 110
 111   return NULL_RTX;
 112 }