Daily bump.
[official-gcc.git] / gcc / rtlhooks.c
blob05b46c3aa9dfb874980795f72a87dc62379c5f5e
1 /* Generic hooks for the RTL middle-end.
2 Copyright (C) 2004-2014 Free Software Foundation, Inc.
4 This file is part of GCC.
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.
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.
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/>. */
20 #include "config.h"
21 #include "system.h"
22 #include "coretypes.h"
23 #include "tm.h"
24 #include "rtl.h"
25 #include "rtlhooks-def.h"
26 #include "expr.h"
27 #include "recog.h"
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. */
36 const struct rtl_hooks general_rtl_hooks = RTL_HOOKS_INITIALIZER;
37 struct rtl_hooks rtl_hooks = RTL_HOOKS_INITIALIZER;
39 rtx
40 gen_lowpart_general (machine_mode mode, rtx x)
42 rtx result = gen_lowpart_common (mode, x);
44 if (result)
45 return result;
46 /* Handle SUBREGs and hard REGs that were rejected by
47 simplify_gen_subreg. */
48 else if (REG_P (x) || GET_CODE (x) == SUBREG)
50 result = gen_lowpart_common (mode, copy_to_reg (x));
51 gcc_assert (result != 0);
52 return result;
54 else
56 int offset = 0;
58 /* The only additional case we can do is MEM. */
59 gcc_assert (MEM_P (x));
61 /* The following exposes the use of "x" to CSE. */
62 if (GET_MODE_SIZE (GET_MODE (x)) <= UNITS_PER_WORD
63 && SCALAR_INT_MODE_P (GET_MODE (x))
64 && TRULY_NOOP_TRUNCATION_MODES_P (mode, GET_MODE (x))
65 && !reload_completed)
66 return gen_lowpart_general (mode, force_reg (GET_MODE (x), x));
68 if (WORDS_BIG_ENDIAN)
69 offset = (MAX (GET_MODE_SIZE (GET_MODE (x)), UNITS_PER_WORD)
70 - MAX (GET_MODE_SIZE (mode), UNITS_PER_WORD));
72 if (BYTES_BIG_ENDIAN)
73 /* Adjust the address so that the address-after-the-data
74 is unchanged. */
75 offset -= (MIN (UNITS_PER_WORD, GET_MODE_SIZE (mode))
76 - MIN (UNITS_PER_WORD, GET_MODE_SIZE (GET_MODE (x))));
78 return adjust_address (x, mode, offset);
82 rtx
83 reg_num_sign_bit_copies_general (const_rtx x ATTRIBUTE_UNUSED,
84 machine_mode mode ATTRIBUTE_UNUSED,
85 const_rtx known_x ATTRIBUTE_UNUSED,
86 machine_mode known_mode ATTRIBUTE_UNUSED,
87 unsigned int known_ret ATTRIBUTE_UNUSED,
88 unsigned int *result ATTRIBUTE_UNUSED)
90 return NULL;
93 rtx
94 reg_nonzero_bits_general (const_rtx x ATTRIBUTE_UNUSED,
95 machine_mode mode ATTRIBUTE_UNUSED,
96 const_rtx known_x ATTRIBUTE_UNUSED,
97 machine_mode known_mode ATTRIBUTE_UNUSED,
98 unsigned HOST_WIDE_INT known_ret ATTRIBUTE_UNUSED,
99 unsigned HOST_WIDE_INT *nonzero ATTRIBUTE_UNUSED)
101 return NULL;
104 bool
105 reg_truncated_to_mode_general (machine_mode mode ATTRIBUTE_UNUSED,
106 const_rtx x ATTRIBUTE_UNUSED)
108 return false;
111 /* Assuming that X is an rtx (e.g., MEM, REG or SUBREG) for a fixed-point
112 number, return an rtx (MEM, SUBREG, or CONST_INT) that refers to the
113 least-significant part of X.
114 MODE specifies how big a part of X to return.
116 If the requested operation cannot be done, 0 is returned.
118 This is similar to gen_lowpart_general. */
121 gen_lowpart_if_possible (machine_mode mode, rtx x)
123 rtx result = gen_lowpart_common (mode, x);
125 if (result)
126 return result;
127 else if (MEM_P (x))
129 /* This is the only other case we handle. */
130 int offset = 0;
131 rtx new_rtx;
133 if (WORDS_BIG_ENDIAN)
134 offset = (MAX (GET_MODE_SIZE (GET_MODE (x)), UNITS_PER_WORD)
135 - MAX (GET_MODE_SIZE (mode), UNITS_PER_WORD));
136 if (BYTES_BIG_ENDIAN)
137 /* Adjust the address so that the address-after-the-data is
138 unchanged. */
139 offset -= (MIN (UNITS_PER_WORD, GET_MODE_SIZE (mode))
140 - MIN (UNITS_PER_WORD, GET_MODE_SIZE (GET_MODE (x))));
142 new_rtx = adjust_address_nv (x, mode, offset);
143 if (! memory_address_addr_space_p (mode, XEXP (new_rtx, 0),
144 MEM_ADDR_SPACE (x)))
145 return 0;
147 return new_rtx;
149 else if (mode != GET_MODE (x) && GET_MODE (x) != VOIDmode
150 && validate_subreg (mode, GET_MODE (x), x,
151 subreg_lowpart_offset (mode, GET_MODE (x))))
152 return gen_lowpart_SUBREG (mode, x);
153 else
154 return 0;