1 /* Common subexpression elimination for GNU compiler. 2 Copyright (C) 1987-2018 Free Software Foundation, Inc. 3 4 This file is part of GCC. 5 6 GCC is free software; you can redistribute it and/or modify it under 7 the terms of the GNU General Public License as published by the Free 8 Software Foundation; either version 3, or (at your option) any later 9 version. 10 11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY 12 WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 for more details. 15 16 You should have received a copy of the GNU General Public License 17 along 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. */ 24 struct 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. */ 47 struct 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. */ 57 struct cselib_set 58 { 59 rtx src; 60 rtx dest; 61 cselib_val *src_elt; 62 cselib_val *dest_addr_elt; 63 }; 64 65 enum cselib_record_what 66 { 67 CSELIB_RECORD_MEMORY = 1, 68 CSELIB_PRESERVE_CONSTANTS = 2 69 }; 70 71 extern void (*cselib_discard_hook) (cselib_val *); 72 extern void (*cselib_record_sets_hook) (rtx_insn *insn, struct cselib_set *sets, 73 int n_sets); 74 75 extern cselib_val *cselib_lookup (rtx, machine_mode, 76 int, machine_mode); 77 extern cselib_val *cselib_lookup_from_insn (rtx, machine_mode, 78 int, machine_mode, rtx_insn *); 79 extern void cselib_init (int); 80 extern void cselib_clear_table (void); 81 extern void cselib_finish (void); 82 extern void cselib_process_insn (rtx_insn *); 83 extern bool fp_setter_insn (rtx_insn *); 84 extern machine_mode cselib_reg_set_mode (const_rtx); 85 extern int rtx_equal_for_cselib_1 (rtx, rtx, machine_mode, int); 86 extern int references_value_p (const_rtx, int); 87 extern rtx cselib_expand_value_rtx (rtx, bitmap, int); 88 typedef rtx (*cselib_expand_callback)(rtx, bitmap, int, void *); 89 extern rtx cselib_expand_value_rtx_cb (rtx, bitmap, int, 90 cselib_expand_callback, void *); 91 extern bool cselib_dummy_expand_value_rtx_cb (rtx, bitmap, int, 92 cselib_expand_callback, void *); 93 extern rtx cselib_subst_to_values (rtx, machine_mode); 94 extern rtx cselib_subst_to_values_from_insn (rtx, machine_mode, rtx_insn *); 95 extern void cselib_invalidate_rtx (rtx); 96 97 extern void cselib_reset_table (unsigned int); 98 extern unsigned int cselib_get_next_uid (void); 99 extern void cselib_preserve_value (cselib_val *); 100 extern bool cselib_preserved_value_p (cselib_val *); 101 extern void cselib_preserve_only_values (void); 102 extern void cselib_preserve_cfa_base_value (cselib_val *, unsigned int); 103 extern void cselib_add_permanent_equiv (cselib_val *, rtx, rtx_insn *); 104 extern bool cselib_have_permanent_equivalences (void); 105 extern void cselib_set_value_sp_based (cselib_val *); 106 extern bool cselib_sp_based_value_p (cselib_val *); 107 108 extern 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. */ 112 113 static inline cselib_val * 114 canonical_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. */ 130 131 static inline int 132 rtx_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