1 /* Generic hooks for the RTL middle-end.
2 Copyright (C) 2004, 2005 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 2, or (at your option) any later
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
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, 51 Franklin Street, Fifth Floor, Boston, MA
23 #include "coretypes.h"
26 #include "rtlhooks-def.h"
31 /* For speed, we will copy the RTX hooks struct member-by-member
32 instead of doing indirect calls. For these reason, we initialize
33 *two* struct rtl_hooks globals: rtl_hooks is the one that is used
34 to actually call the hooks, while general_rtl_hooks is used
35 to restore the hooks by passes that modify them. */
37 const struct rtl_hooks general_rtl_hooks = RTL_HOOKS_INITIALIZER;
38 struct rtl_hooks rtl_hooks = RTL_HOOKS_INITIALIZER;
41 gen_lowpart_general (enum machine_mode mode, rtx x)
43 rtx result = gen_lowpart_common (mode, x);
49 /* Must be a hard reg that's not valid in MODE. */
50 result = gen_lowpart_common (mode, copy_to_reg (x));
51 gcc_assert (result != 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 (GET_MODE_BITSIZE (mode),
65 GET_MODE_BITSIZE (GET_MODE (x)))
67 return gen_lowpart_general (mode, force_reg (GET_MODE (x), x));
70 offset = (MAX (GET_MODE_SIZE (GET_MODE (x)), UNITS_PER_WORD)
71 - MAX (GET_MODE_SIZE (mode), UNITS_PER_WORD));
74 /* Adjust the address so that the address-after-the-data
76 offset -= (MIN (UNITS_PER_WORD, GET_MODE_SIZE (mode))
77 - MIN (UNITS_PER_WORD, GET_MODE_SIZE (GET_MODE (x))));
79 return adjust_address (x, mode, offset);
83 /* Similar to gen_lowpart, but cannot emit any instruction via
84 copy_to_reg or force_reg. Mainly used in simplify-rtx.c. */
86 gen_lowpart_no_emit_general (enum machine_mode mode, rtx x)
88 rtx result = gen_lowpart_if_possible (mode, x);
96 reg_num_sign_bit_copies_general (rtx x ATTRIBUTE_UNUSED,
97 enum machine_mode mode ATTRIBUTE_UNUSED,
98 rtx known_x ATTRIBUTE_UNUSED,
99 enum machine_mode known_mode ATTRIBUTE_UNUSED,
100 unsigned int known_ret ATTRIBUTE_UNUSED,
101 unsigned int *result ATTRIBUTE_UNUSED)
107 reg_nonzero_bits_general (rtx x ATTRIBUTE_UNUSED,
108 enum machine_mode mode ATTRIBUTE_UNUSED,
109 rtx known_x ATTRIBUTE_UNUSED,
110 enum machine_mode known_mode ATTRIBUTE_UNUSED,
111 unsigned HOST_WIDE_INT known_ret ATTRIBUTE_UNUSED,
112 unsigned HOST_WIDE_INT *nonzero ATTRIBUTE_UNUSED)
117 /* Assuming that X is an rtx (e.g., MEM, REG or SUBREG) for a fixed-point
118 number, return an rtx (MEM, SUBREG, or CONST_INT) that refers to the
119 least-significant part of X.
120 MODE specifies how big a part of X to return.
122 If the requested operation cannot be done, 0 is returned.
124 This is similar to gen_lowpart_general. */
127 gen_lowpart_if_possible (enum machine_mode mode, rtx x)
129 rtx result = gen_lowpart_common (mode, x);
135 /* This is the only other case we handle. */
139 if (WORDS_BIG_ENDIAN)
140 offset = (MAX (GET_MODE_SIZE (GET_MODE (x)), UNITS_PER_WORD)
141 - MAX (GET_MODE_SIZE (mode), UNITS_PER_WORD));
142 if (BYTES_BIG_ENDIAN)
143 /* Adjust the address so that the address-after-the-data is
145 offset -= (MIN (UNITS_PER_WORD, GET_MODE_SIZE (mode))
146 - MIN (UNITS_PER_WORD, GET_MODE_SIZE (GET_MODE (x))));
148 new = adjust_address_nv (x, mode, offset);
149 if (! memory_address_p (mode, XEXP (new, 0)))
154 else if (mode != GET_MODE (x) && GET_MODE (x) != VOIDmode)
155 return gen_lowpart_SUBREG (mode, x);