gcc/rtlhooks.c

   1 /* Generic hooks for the RTL middle-end.
   2    Copyright (C) 2004 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 2, 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 COPYING.  If not, write to the Free
  18 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  19 02111-1307, USA.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "tm.h"
  25 #include "rtl.h"
  26 #include "rtlhooks-def.h"
  27 #include "expr.h"
  28 \f
  29
  30 /* For speed, we will copy the RTX hooks struct member-by-member
  31    instead of doing indirect calls.  For these reason, we initialize
  32    *two* struct rtl_hooks globals: rtl_hooks is the one that is used
  33    to actually call the hooks, while general_rtl_hooks is used
  34    to restore the hooks by passes that modify them.  */
  35
  36 const struct rtl_hooks general_rtl_hooks = RTL_HOOKS_INITIALIZER;
  37 struct rtl_hooks rtl_hooks = RTL_HOOKS_INITIALIZER;
  38
  39 rtx
  40 gen_lowpart_general (enum machine_mode mode, rtx x)
  41 {
  42   rtx result = gen_lowpart_common (mode, x);
  43
  44   if (result)
  45     return result;
  46   else if (REG_P (x))
  47     {
  48       /* Must be a hard reg that's not valid in MODE.  */
  49       result = gen_lowpart_common (mode, copy_to_reg (x));
  50       if (result == 0)
  51         abort ();
  52       return result;
  53     }
  54   else if (GET_CODE (x) == MEM)
  55     {
  56       /* The only additional case we can do is MEM.  */
  57       int offset = 0;
  58
  59       /* The following exposes the use of "x" to CSE.  */
  60       if (GET_MODE_SIZE (GET_MODE (x)) <= UNITS_PER_WORD
  61           && SCALAR_INT_MODE_P (GET_MODE (x))
  62           && TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (mode),
  63                                     GET_MODE_BITSIZE (GET_MODE (x)))
  64           && ! no_new_pseudos)
  65         return gen_lowpart_general (mode, force_reg (GET_MODE (x), x));
  66
  67       if (WORDS_BIG_ENDIAN)
  68         offset = (MAX (GET_MODE_SIZE (GET_MODE (x)), UNITS_PER_WORD)
  69                   - MAX (GET_MODE_SIZE (mode), UNITS_PER_WORD));
  70
  71       if (BYTES_BIG_ENDIAN)
  72         /* Adjust the address so that the address-after-the-data
  73            is unchanged.  */
  74         offset -= (MIN (UNITS_PER_WORD, GET_MODE_SIZE (mode))
  75                    - MIN (UNITS_PER_WORD, GET_MODE_SIZE (GET_MODE (x))));
  76
  77       return adjust_address (x, mode, offset);
  78     }
  79   else if (GET_CODE (x) == ADDRESSOF)
  80     return gen_lowpart_general (mode, force_reg (GET_MODE (x), x));
  81   else
  82     abort ();
  83 }
  84
  85 rtx
  86 reg_num_sign_bit_copies_general (rtx x ATTRIBUTE_UNUSED,
  87                                  enum machine_mode mode ATTRIBUTE_UNUSED,
  88                                  rtx known_x ATTRIBUTE_UNUSED,
  89                                  enum machine_mode known_mode ATTRIBUTE_UNUSED,
  90                                  unsigned int known_ret ATTRIBUTE_UNUSED,
  91                                  unsigned int *result ATTRIBUTE_UNUSED)
  92 {
  93   return NULL;
  94 }
  95
  96 rtx
  97 reg_nonzero_bits_general (rtx x ATTRIBUTE_UNUSED,
  98                           enum machine_mode mode ATTRIBUTE_UNUSED,
  99                           rtx known_x ATTRIBUTE_UNUSED,
 100                           enum machine_mode known_mode ATTRIBUTE_UNUSED,
 101                           unsigned HOST_WIDE_INT known_ret ATTRIBUTE_UNUSED,
 102                           unsigned HOST_WIDE_INT *nonzero ATTRIBUTE_UNUSED)
 103 {
 104   return NULL;
 105 }