gcc/cselib.h

   1 /* Common subexpression elimination for GNU compiler.
   2    Copyright (C) 1987-2014 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   /* 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.  */
  46 struct 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.  */
  56 struct cselib_set
  57 {
  58   rtx src;
  59   rtx dest;
  60   cselib_val *src_elt;
  61   cselib_val *dest_addr_elt;
  62 };
  63
  64 enum cselib_record_what
  65 {
  66   CSELIB_RECORD_MEMORY = 1,
  67   CSELIB_PRESERVE_CONSTANTS = 2
  68 };
  69
  70 extern void (*cselib_discard_hook) (cselib_val *);
  71 extern void (*cselib_record_sets_hook) (rtx_insn *insn, struct cselib_set *sets,
  72                                         int n_sets);
  73
  74 extern cselib_val *cselib_lookup (rtx, machine_mode,
  75                                   int, machine_mode);
  76 extern cselib_val *cselib_lookup_from_insn (rtx, machine_mode,
  77                                             int, machine_mode, rtx_insn *);
  78 extern void cselib_init (int);
  79 extern void cselib_clear_table (void);
  80 extern void cselib_finish (void);
  81 extern void cselib_process_insn (rtx_insn *);
  82 extern bool fp_setter_insn (rtx);
  83 extern machine_mode cselib_reg_set_mode (const_rtx);
  84 extern int rtx_equal_for_cselib_p (rtx, rtx);
  85 extern int references_value_p (const_rtx, int);
  86 extern rtx cselib_expand_value_rtx (rtx, bitmap, int);
  87 typedef rtx (*cselib_expand_callback)(rtx, bitmap, int, void *);
  88 extern rtx cselib_expand_value_rtx_cb (rtx, bitmap, int,
  89                                        cselib_expand_callback, void *);
  90 extern bool cselib_dummy_expand_value_rtx_cb (rtx, bitmap, int,
  91                                               cselib_expand_callback, void *);
  92 extern rtx cselib_subst_to_values (rtx, machine_mode);
  93 extern rtx cselib_subst_to_values_from_insn (rtx, machine_mode, rtx_insn *);
  94 extern void cselib_invalidate_rtx (rtx);
  95
  96 extern void cselib_reset_table (unsigned int);
  97 extern unsigned int cselib_get_next_uid (void);
  98 extern void cselib_preserve_value (cselib_val *);
  99 extern bool cselib_preserved_value_p (cselib_val *);
 100 extern void cselib_preserve_only_values (void);
 101 extern void cselib_preserve_cfa_base_value (cselib_val *, unsigned int);
 102 extern void cselib_add_permanent_equiv (cselib_val *, rtx, rtx_insn *);
 103 extern bool cselib_have_permanent_equivalences (void);
 104 extern void cselib_set_value_sp_based (cselib_val *);
 105 extern bool cselib_sp_based_value_p (cselib_val *);
 106
 107 extern 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
 112 static inline cselib_val *
 113 canonical_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 */