1/* Generic hooks for the RTL middle-end.
2 Copyright (C) 2004-2017 Free Software Foundation, Inc.
3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify it under
7the terms of the GNU General Public License as published by the Free
8Software Foundation; either version 3, or (at your option) any later
9version.
10
11GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12WARRANTY; without even the implied warranty of MERCHANTABILITY or
13FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14for more details.
15
16You should have received a copy of the GNU General Public License
17along 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 "function.h"
25#include "rtl.h"
26#include "tree.h"
27#include "insn-config.h"
28#include "memmodel.h"
29#include "emit-rtl.h"
30#include "recog.h"
31#include "rtlhooks-def.h"
32#include "explow.h"
33#include "target.h"
34
35
36/* For speed, we will copy the RTX hooks struct member-by-member
37 instead of doing indirect calls. For these reason, we initialize
38 *two* struct rtl_hooks globals: rtl_hooks is the one that is used
39 to actually call the hooks, while general_rtl_hooks is used
40 to restore the hooks by passes that modify them. */
41
42const struct rtl_hooks general_rtl_hooks = RTL_HOOKS_INITIALIZER;
43struct rtl_hooks rtl_hooks = RTL_HOOKS_INITIALIZER;
44
45rtx
46gen_lowpart_general (machine_mode mode, rtx x)
47{
48 rtx result = gen_lowpart_common (mode, x);
49
50 if (result)
51 return result;
52 /* Handle SUBREGs and hard REGs that were rejected by
53 simplify_gen_subreg. */
54 else if (REG_P (x) || GET_CODE (x) == SUBREG)
55 {
56 result = gen_lowpart_common (mode, copy_to_reg (x));
57 gcc_assert (result != 0);
58 return result;
59 }
60 else
61 {
62 /* The only additional case we can do is MEM. */
63 gcc_assert (MEM_P (x));
64
65 /* The following exposes the use of "x" to CSE. */
66 scalar_int_mode xmode;
67 if (is_a <scalar_int_mode> (GET_MODE (x), &xmode)
68 && GET_MODE_SIZE (xmode) <= UNITS_PER_WORD
69 && TRULY_NOOP_TRUNCATION_MODES_P (mode, xmode)
70 && !reload_completed)
71 return gen_lowpart_general (mode, force_reg (xmode, x));
72
73 HOST_WIDE_INT offset = byte_lowpart_offset (mode, GET_MODE (x));
74 return adjust_address (x, mode, offset);
75 }
76}
77
78rtx
79reg_num_sign_bit_copies_general (const_rtx, scalar_int_mode, scalar_int_mode,
80 unsigned int *)
81{
82 return NULL;
83}
84
85rtx
86reg_nonzero_bits_general (const_rtx, scalar_int_mode, scalar_int_mode,
87 unsigned HOST_WIDE_INT *)
88{
89 return NULL;
90}
91
92bool
93reg_truncated_to_mode_general (machine_mode mode ATTRIBUTE_UNUSED,
94 const_rtx x ATTRIBUTE_UNUSED)
95{
96 return false;
97}
98
99/* Assuming that X is an rtx (e.g., MEM, REG or SUBREG) for a fixed-point
100 number, return an rtx (MEM, SUBREG, or CONST_INT) that refers to the
101 least-significant part of X.
102 MODE specifies how big a part of X to return.
103
104 If the requested operation cannot be done, 0 is returned.
105
106 This is similar to gen_lowpart_general. */
107
108rtx
109gen_lowpart_if_possible (machine_mode mode, rtx x)
110{
111 rtx result = gen_lowpart_common (mode, x);
112
113 if (result)
114 return result;
115 else if (MEM_P (x))
116 {
117 /* This is the only other case we handle. */
118 HOST_WIDE_INT offset = byte_lowpart_offset (mode, GET_MODE (x));
119 rtx new_rtx = adjust_address_nv (x, mode, offset);
120 if (! memory_address_addr_space_p (mode, XEXP (new_rtx, 0),
121 MEM_ADDR_SPACE (x)))
122 return 0;
123
124 return new_rtx;
125 }
126 else if (mode != GET_MODE (x) && GET_MODE (x) != VOIDmode
127 && validate_subreg (mode, GET_MODE (x), x,
128 subreg_lowpart_offset (mode, GET_MODE (x))))
129 return gen_lowpart_SUBREG (mode, x);
130 else
131 return 0;
132}
133
134