1/* Common subexpression elimination for GNU compiler.
2   Copyright (C) 1987-2015 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#ifndef GCC_CSELIB_H
21#define GCC_CSELIB_H
22
23/* Describe a value.  */
24struct cselib_val {
25  /* The hash value.  */
26  unsigned int hash;
27
28  /* A unique id assigned to values.  */
29  int uid;
30
31  /* A VALUE rtx that points back to this structure.  */
32  rtx val_rtx;
33
34  /* All rtl expressions that hold this value at the current time during a
35     scan.  */
36  struct elt_loc_list *locs;
37
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 *next_containing_mem;
43};
44
45/* A list of rtl expressions that hold the same value.  */
46struct elt_loc_list {
47  /* Next element in the list.  */
48  struct elt_loc_list *next;
49  /* An rtl expression that holds the value.  */
50  rtx loc;
51  /* The insn that made the equivalence.  */
52  rtx_insn *setting_insn;
53};
54
55/* Describe a single set that is part of an insn.  */
56struct cselib_set
57{
58  rtx src;
59  rtx dest;
60  cselib_val *src_elt;
61  cselib_val *dest_addr_elt;
62};
63
64enum cselib_record_what
65{
66  CSELIB_RECORD_MEMORY = 1,
67  CSELIB_PRESERVE_CONSTANTS = 2
68};
69
70extern void (*cselib_discard_hook) (cselib_val *);
71extern void (*cselib_record_sets_hook) (rtx_insn *insn, struct cselib_set *sets,
72					int n_sets);
73
74extern cselib_val *cselib_lookup (rtx, machine_mode,
75				  int, machine_mode);
76extern cselib_val *cselib_lookup_from_insn (rtx, machine_mode,
77					    int, machine_mode, rtx_insn *);
78extern void cselib_init (int);
79extern void cselib_clear_table (void);
80extern void cselib_finish (void);
81extern void cselib_process_insn (rtx_insn *);
82extern bool fp_setter_insn (rtx);
83extern machine_mode cselib_reg_set_mode (const_rtx);
84extern int rtx_equal_for_cselib_p (rtx, rtx);
85extern int references_value_p (const_rtx, int);
86extern rtx cselib_expand_value_rtx (rtx, bitmap, int);
87typedef rtx (*cselib_expand_callback)(rtx, bitmap, int, void *);
88extern rtx cselib_expand_value_rtx_cb (rtx, bitmap, int,
89				       cselib_expand_callback, void *);
90extern bool cselib_dummy_expand_value_rtx_cb (rtx, bitmap, int,
91					      cselib_expand_callback, void *);
92extern rtx cselib_subst_to_values (rtx, machine_mode);
93extern rtx cselib_subst_to_values_from_insn (rtx, machine_mode, rtx_insn *);
94extern void cselib_invalidate_rtx (rtx);
95
96extern void cselib_reset_table (unsigned int);
97extern unsigned int cselib_get_next_uid (void);
98extern void cselib_preserve_value (cselib_val *);
99extern bool cselib_preserved_value_p (cselib_val *);
100extern void cselib_preserve_only_values (void);
101extern void cselib_preserve_cfa_base_value (cselib_val *, unsigned int);
102extern void cselib_add_permanent_equiv (cselib_val *, rtx, rtx_insn *);
103extern bool cselib_have_permanent_equivalences (void);
104extern void cselib_set_value_sp_based (cselib_val *);
105extern bool cselib_sp_based_value_p (cselib_val *);
106
107extern void dump_cselib_table (FILE *);
108
109/* Return the canonical value for VAL, following the equivalence chain
110   towards the earliest (== lowest uid) equivalent value.  */
111
112static inline cselib_val *
113canonical_cselib_val (cselib_val *val)
114{
115  cselib_val *canon;
116
117  if (!val->locs || val->locs->next
118      || !val->locs->loc || GET_CODE (val->locs->loc) != VALUE
119      || val->uid < CSELIB_VAL_PTR (val->locs->loc)->uid)
120    return val;
121
122  canon = CSELIB_VAL_PTR (val->locs->loc);
123  gcc_checking_assert (canonical_cselib_val (canon) == canon);
124  return canon;
125}
126
127#endif /* GCC_CSELIB_H */
128