gcc/cselib.h

   1 /* Common subexpression elimination for GNU compiler.
   2    Copyright (C) 1987-2017 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 */