1/* Common subexpression elimination for GNU compiler.
2   Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3   1999, 2003, 2004, 2005 Free Software Foundation, Inc.
4
5This file is part of GCC.
6
7GCC is free software; you can redistribute it and/or modify it under
8the terms of the GNU General Public License as published by the Free
9Software Foundation; either version 2, or (at your option) any later
10version.
11
12GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13WARRANTY; without even the implied warranty of MERCHANTABILITY or
14FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
15for more details.
16
17You should have received a copy of the GNU General Public License
18along with GCC; see the file COPYING.  If not, write to the Free
19Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
2002110-1301, USA.  */
21
22/* Describe a value.  */
23typedef struct cselib_val_struct GTY(())
24{
25  /* The hash value.  */
26  unsigned int value;
27  union cselib_val_u
28  {
29    /* A VALUE rtx that points back to this structure.  */
30    rtx GTY ((tag ("1"))) val_rtx;
31    /* Used to keep a list of free cselib_val structures.  */
32    struct cselib_val_struct * GTY ((skip)) next_free;
33  } GTY ((desc ("1"))) u;
34
35  /* All rtl expressions that hold this value at the current time during a
36     scan.  */
37  struct elt_loc_list *locs;
38  /* If this value is used as an address, points to a list of values that
39     use it as an address in a MEM.  */
40  struct elt_list *addr_list;
41
42  struct cselib_val_struct *next_containing_mem;
43} cselib_val;
44
45/* A list of rtl expressions that hold the same value.  */
46struct elt_loc_list GTY(())
47{
48  /* Next element in the list.  */
49  struct elt_loc_list *next;
50  /* An rtl expression that holds the value.  */
51  rtx loc;
52  /* The insn that made the equivalence.  */
53  rtx setting_insn;
54  /* True when setting insn is inside libcall.  */
55  bool in_libcall;
56};
57
58/* A list of cselib_val structures.  */
59struct elt_list GTY(())
60{
61  struct elt_list *next;
62  cselib_val *elt;
63};
64
65extern cselib_val *cselib_lookup (rtx, enum machine_mode, int);
66extern void cselib_init (bool record_memory);
67extern void cselib_clear_table (void);
68extern void cselib_finish (void);
69extern void cselib_process_insn (rtx);
70extern enum machine_mode cselib_reg_set_mode (rtx);
71extern int rtx_equal_for_cselib_p (rtx, rtx);
72extern int references_value_p (rtx, int);
73extern rtx cselib_subst_to_values (rtx);
74extern void cselib_invalidate_rtx (rtx);
75