1/* Common subexpression elimination for GNU compiler.
2 Copyright (C) 1987-2017 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#ifndef GCC_CSELIB_H
21#define GCC_CSELIB_H
22
23/* Describe a value. */
24struct cselib_val
25{
26 /* The hash value. */
27 unsigned int hash;
28
29 /* A unique id assigned to values. */
30 int uid;
31
32 /* A VALUE rtx that points back to this structure. */
33 rtx val_rtx;
34
35 /* All rtl expressions that hold this value at the current time during a
36 scan. */
37 struct elt_loc_list *locs;
38
39 /* If this value is used as an address, points to a list of values that
40 use it as an address in a MEM. */
41 struct elt_list *addr_list;
42
43 struct cselib_val *next_containing_mem;
44};
45
46/* A list of rtl expressions that hold the same value. */
47struct elt_loc_list {
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_insn *setting_insn;
54};
55
56/* Describe a single set that is part of an insn. */
57struct cselib_set
58{
59 rtx src;
60 rtx dest;
61 cselib_val *src_elt;
62 cselib_val *dest_addr_elt;
63};
64
65enum cselib_record_what
66{
67 CSELIB_RECORD_MEMORY = 1,
68 CSELIB_PRESERVE_CONSTANTS = 2
69};
70
71extern void (*cselib_discard_hook) (cselib_val *);
72extern void (*cselib_record_sets_hook) (rtx_insn *insn, struct cselib_set *sets,
73 int n_sets);
74
75extern cselib_val *cselib_lookup (rtx, machine_mode,
76 int, machine_mode);
77extern cselib_val *cselib_lookup_from_insn (rtx, machine_mode,
78 int, machine_mode, rtx_insn *);
79extern void cselib_init (int);
80extern void cselib_clear_table (void);
81extern void cselib_finish (void);
82extern void cselib_process_insn (rtx_insn *);
83extern bool fp_setter_insn (rtx_insn *);
84extern machine_mode cselib_reg_set_mode (const_rtx);
85extern int rtx_equal_for_cselib_1 (rtx, rtx, machine_mode, int);
86extern int references_value_p (const_rtx, int);
87extern rtx cselib_expand_value_rtx (rtx, bitmap, int);
88typedef rtx (*cselib_expand_callback)(rtx, bitmap, int, void *);
89extern rtx cselib_expand_value_rtx_cb (rtx, bitmap, int,
90 cselib_expand_callback, void *);
91extern bool cselib_dummy_expand_value_rtx_cb (rtx, bitmap, int,
92 cselib_expand_callback, void *);
93extern rtx cselib_subst_to_values (rtx, machine_mode);
94extern rtx cselib_subst_to_values_from_insn (rtx, machine_mode, rtx_insn *);
95extern void cselib_invalidate_rtx (rtx);
96
97extern void cselib_reset_table (unsigned int);
98extern unsigned int cselib_get_next_uid (void);
99extern void cselib_preserve_value (cselib_val *);
100extern bool cselib_preserved_value_p (cselib_val *);
101extern void cselib_preserve_only_values (void);
102extern void cselib_preserve_cfa_base_value (cselib_val *, unsigned int);
103extern void cselib_add_permanent_equiv (cselib_val *, rtx, rtx_insn *);
104extern bool cselib_have_permanent_equivalences (void);
105extern void cselib_set_value_sp_based (cselib_val *);
106extern bool cselib_sp_based_value_p (cselib_val *);
107
108extern void dump_cselib_table (FILE *);
109
110/* Return the canonical value for VAL, following the equivalence chain
111 towards the earliest (== lowest uid) equivalent value. */
112
113static inline cselib_val *
114canonical_cselib_val (cselib_val *val)
115{
116 cselib_val *canon;
117
118 if (!val->locs || val->locs->next
119 || !val->locs->loc || GET_CODE (val->locs->loc) != VALUE
120 || val->uid < CSELIB_VAL_PTR (val->locs->loc)->uid)
121 return val;
122
123 canon = CSELIB_VAL_PTR (val->locs->loc);
124 gcc_checking_assert (canonical_cselib_val (canon) == canon);
125 return canon;
126}
127
128/* Return nonzero if we can prove that X and Y contain the same value, taking
129 our gathered information into account. */
130
131static inline int
132rtx_equal_for_cselib_p (rtx x, rtx y)
133{
134 if (x == y)
135 return 1;
136
137 return rtx_equal_for_cselib_1 (x, y, VOIDmode, 0);
138}
139
140#endif /* GCC_CSELIB_H */
141