cselib.h revision 117395 
1/* Common subexpression elimination for GNU compiler.
2   Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3   1999 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, 59 Temple Place - Suite 330, Boston, MA
2002111-1307, 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} cselib_val;
42
43/* A list of rtl expressions that hold the same value.  */
44struct elt_loc_list GTY(())
45{
46  /* Next element in the list.  */
47  struct elt_loc_list *next;
48  /* An rtl expression that holds the value.  */
49  rtx loc;
50  /* The insn that made the equivalence.  */
51  rtx setting_insn;
52  /* True when setting insn is inside libcall.  */
53  bool in_libcall;
54};
55
56/* A list of cselib_val structures.  */
57struct elt_list GTY(())
58{
59  struct elt_list *next;
60  cselib_val *elt;
61};
62
63extern cselib_val *cselib_lookup	PARAMS ((rtx, enum machine_mode, int));
64extern void cselib_update_varray_sizes	PARAMS ((void));
65extern void cselib_init			PARAMS ((void));
66extern void cselib_finish		PARAMS ((void));
67extern void cselib_process_insn		PARAMS ((rtx));
68extern int rtx_equal_for_cselib_p	PARAMS ((rtx, rtx));
69extern int references_value_p		PARAMS ((rtx, int));
70extern rtx cselib_subst_to_values	PARAMS ((rtx));
71