1 /* Common subexpression elimination for GNU compiler. 2 Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 3 1998, 1999, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 4 Free Software Foundation, Inc. 5 6 This file is part of GCC. 7 8 GCC is free software; you can redistribute it and/or modify it under 9 the terms of the GNU General Public License as published by the Free 10 Software Foundation; either version 3, or (at your option) any later 11 version. 12 13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY 14 WARRANTY; without even the implied warranty of MERCHANTABILITY or 15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 16 for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with GCC; see the file COPYING3. If not see 20 <http://www.gnu.org/licenses/>. */ 21 22 /* Describe a value. */ 23 typedef struct cselib_val_struct { 24 /* The hash value. */ 25 unsigned int hash; 26 27 /* A unique id assigned to values. */ 28 int uid; 29 30 /* A VALUE rtx that points back to this structure. */ 31 rtx val_rtx; 32 33 /* All rtl expressions that hold this value at the current time during a 34 scan. */ 35 struct elt_loc_list *locs; 36 37 /* If this value is used as an address, points to a list of values that 38 use it as an address in a MEM. */ 39 struct elt_list *addr_list; 40 41 struct cselib_val_struct *next_containing_mem; 42 } cselib_val; 43 44 /* A list of rtl expressions that hold the same value. */ 45 struct elt_loc_list { 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 }; 53 54 /* Describe a single set that is part of an insn. */ 55 struct cselib_set 56 { 57 rtx src; 58 rtx dest; 59 cselib_val *src_elt; 60 cselib_val *dest_addr_elt; 61 }; 62 63 enum cselib_record_what 64 { 65 CSELIB_RECORD_MEMORY = 1, 66 CSELIB_PRESERVE_CONSTANTS = 2 67 }; 68 69 extern void (*cselib_discard_hook) (cselib_val *); 70 extern void (*cselib_record_sets_hook) (rtx insn, struct cselib_set *sets, 71 int n_sets); 72 73 extern cselib_val *cselib_lookup (rtx, enum machine_mode, 74 int, enum machine_mode); 75 extern cselib_val *cselib_lookup_from_insn (rtx, enum machine_mode, 76 int, enum machine_mode, rtx); 77 extern void cselib_init (int); 78 extern void cselib_clear_table (void); 79 extern void cselib_finish (void); 80 extern void cselib_process_insn (rtx); 81 extern enum machine_mode cselib_reg_set_mode (const_rtx); 82 extern int rtx_equal_for_cselib_p (rtx, rtx); 83 extern int references_value_p (const_rtx, int); 84 extern rtx cselib_expand_value_rtx (rtx, bitmap, int); 85 typedef rtx (*cselib_expand_callback)(rtx, bitmap, int, void *); 86 extern rtx cselib_expand_value_rtx_cb (rtx, bitmap, int, 87 cselib_expand_callback, void *); 88 extern bool cselib_dummy_expand_value_rtx_cb (rtx, bitmap, int, 89 cselib_expand_callback, void *); 90 extern rtx cselib_subst_to_values (rtx, enum machine_mode); 91 extern rtx cselib_subst_to_values_from_insn (rtx, enum machine_mode, rtx); 92 extern void cselib_invalidate_rtx (rtx); 93 94 extern void cselib_reset_table (unsigned int); 95 extern unsigned int cselib_get_next_uid (void); 96 extern void cselib_preserve_value (cselib_val *); 97 extern bool cselib_preserved_value_p (cselib_val *); 98 extern void cselib_preserve_only_values (void); 99 extern void cselib_preserve_cfa_base_value (cselib_val *, unsigned int); 100 extern void cselib_add_permanent_equiv (cselib_val *, rtx, rtx); 101 extern bool cselib_have_permanent_equivalences (void); 102 103 extern void dump_cselib_table (FILE *); 104 105 /* Return the canonical value for VAL, following the equivalence chain 106 towards the earliest (== lowest uid) equivalent value. */ 107 108 static inline cselib_val * 109 canonical_cselib_val (cselib_val *val) 110 { 111 cselib_val *canon; 112 113 if (!val->locs || val->locs->next 114 || !val->locs->loc || GET_CODE (val->locs->loc) != VALUE 115 || val->uid < CSELIB_VAL_PTR (val->locs->loc)->uid) 116 return val; 117 118 canon = CSELIB_VAL_PTR (val->locs->loc); 119 gcc_checking_assert (canonical_cselib_val (canon) == canon); 120 return canon; 121 } 122