summaryrefslogtreecommitdiff
path: root/gcc/rtlhooks.c
blob: 654f2825fd93199c1fc6991d83a45efd53c5f797 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
/* Generic hooks for the RTL middle-end.
   Copyright (C) 2004-2017 Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "function.h"
#include "rtl.h"
#include "tree.h"
#include "insn-config.h"
#include "memmodel.h"
#include "emit-rtl.h"
#include "recog.h"
#include "rtlhooks-def.h"
#include "explow.h"


/* For speed, we will copy the RTX hooks struct member-by-member
   instead of doing indirect calls.  For these reason, we initialize
   *two* struct rtl_hooks globals: rtl_hooks is the one that is used
   to actually call the hooks, while general_rtl_hooks is used
   to restore the hooks by passes that modify them.  */

const struct rtl_hooks general_rtl_hooks = RTL_HOOKS_INITIALIZER;
struct rtl_hooks rtl_hooks = RTL_HOOKS_INITIALIZER;

rtx
gen_lowpart_general (machine_mode mode, rtx x)
{
  rtx result = gen_lowpart_common (mode, x);

  if (result)
    return result;
  /* Handle SUBREGs and hard REGs that were rejected by
     simplify_gen_subreg.  */
  else if (REG_P (x) || GET_CODE (x) == SUBREG)
    {
      result = gen_lowpart_common (mode, copy_to_reg (x));
      gcc_assert (result != 0);
      return result;
    }
  else
    {
      int offset = 0;

      /* The only additional case we can do is MEM.  */
      gcc_assert (MEM_P (x));

      /* The following exposes the use of "x" to CSE.  */
      if (GET_MODE_SIZE (GET_MODE (x)) <= UNITS_PER_WORD
	  && SCALAR_INT_MODE_P (GET_MODE (x))
	  && TRULY_NOOP_TRUNCATION_MODES_P (mode, GET_MODE (x))
	  && !reload_completed)
	return gen_lowpart_general (mode, force_reg (GET_MODE (x), x));

      if (WORDS_BIG_ENDIAN)
	offset = (MAX (GET_MODE_SIZE (GET_MODE (x)), UNITS_PER_WORD)
		  - MAX (GET_MODE_SIZE (mode), UNITS_PER_WORD));

      if (BYTES_BIG_ENDIAN)
	/* Adjust the address so that the address-after-the-data
	   is unchanged.  */
	offset -= (MIN (UNITS_PER_WORD, GET_MODE_SIZE (mode))
		   - MIN (UNITS_PER_WORD, GET_MODE_SIZE (GET_MODE (x))));

      return adjust_address (x, mode, offset);
    }
}

rtx
reg_num_sign_bit_copies_general (const_rtx x ATTRIBUTE_UNUSED,
				 machine_mode mode ATTRIBUTE_UNUSED,
                                 const_rtx known_x ATTRIBUTE_UNUSED,
				 machine_mode known_mode ATTRIBUTE_UNUSED,
                                 unsigned int known_ret ATTRIBUTE_UNUSED,
                                 unsigned int *result ATTRIBUTE_UNUSED)
{
  return NULL;
}

rtx
reg_nonzero_bits_general (const_rtx x ATTRIBUTE_UNUSED,
			  machine_mode mode ATTRIBUTE_UNUSED,
			  const_rtx known_x ATTRIBUTE_UNUSED,
                          machine_mode known_mode ATTRIBUTE_UNUSED,
                          unsigned HOST_WIDE_INT known_ret ATTRIBUTE_UNUSED,
                          unsigned HOST_WIDE_INT *nonzero ATTRIBUTE_UNUSED)
{
  return NULL;
}

bool
reg_truncated_to_mode_general (machine_mode mode ATTRIBUTE_UNUSED,
			       const_rtx x ATTRIBUTE_UNUSED)
{
  return false;
}

/* Assuming that X is an rtx (e.g., MEM, REG or SUBREG) for a fixed-point
   number, return an rtx (MEM, SUBREG, or CONST_INT) that refers to the
   least-significant part of X.
   MODE specifies how big a part of X to return.

   If the requested operation cannot be done, 0 is returned.

   This is similar to gen_lowpart_general.  */

rtx
gen_lowpart_if_possible (machine_mode mode, rtx x)
{
  rtx result = gen_lowpart_common (mode, x);

  if (result)
    return result;
  else if (MEM_P (x))
    {
      /* This is the only other case we handle.  */
      int offset = 0;
      rtx new_rtx;

      if (WORDS_BIG_ENDIAN)
	offset = (MAX (GET_MODE_SIZE (GET_MODE (x)), UNITS_PER_WORD)
		  - MAX (GET_MODE_SIZE (mode), UNITS_PER_WORD));
      if (BYTES_BIG_ENDIAN)
	/* Adjust the address so that the address-after-the-data is
	   unchanged.  */
	offset -= (MIN (UNITS_PER_WORD, GET_MODE_SIZE (mode))
		   - MIN (UNITS_PER_WORD, GET_MODE_SIZE (GET_MODE (x))));

      new_rtx = adjust_address_nv (x, mode, offset);
      if (! memory_address_addr_space_p (mode, XEXP (new_rtx, 0),
					 MEM_ADDR_SPACE (x)))
	return 0;

      return new_rtx;
    }
  else if (mode != GET_MODE (x) && GET_MODE (x) != VOIDmode
	   && validate_subreg (mode, GET_MODE (x), x,
			        subreg_lowpart_offset (mode, GET_MODE (x))))
    return gen_lowpart_SUBREG (mode, x);
  else
    return 0;
}