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 /* Describe a value.  */
  21 struct cselib_val {
  22   /* The hash value.  */
  23   unsigned int hash;
  24
  25   /* A unique id assigned to values.  */
  26   int uid;
  27
  28   /* A VALUE rtx that points back to this structure.  */
  29   rtx val_rtx;
  30
  31   /* All rtl expressions that hold this value at the current time during a
  32      scan.  */
  33   struct elt_loc_list *locs;
  34
  35   /* If this value is used as an address, points to a list of values that
  36      use it as an address in a MEM.  */
  37   struct elt_list *addr_list;
  38
  39   struct cselib_val *next_containing_mem;
  40 };
  41
  42 /* A list of rtl expressions that hold the same value.  */
  43 struct elt_loc_list {
  44   /* Next element in the list.  */
  45   struct elt_loc_list *next;
  46   /* An rtl expression that holds the value.  */
  47   rtx loc;
  48   /* The insn that made the equivalence.  */
  49   rtx setting_insn;
  50 };
  51
  52 /* Describe a single set that is part of an insn.  */
  53 struct cselib_set
  54 {
  55   rtx src;
  56   rtx dest;
  57   cselib_val *src_elt;
  58   cselib_val *dest_addr_elt;
  59 };
  60
  61 enum cselib_record_what
  62 {
  63   CSELIB_RECORD_MEMORY = 1,
  64   CSELIB_PRESERVE_CONSTANTS = 2
  65 };
  66
  67 extern void (*cselib_discard_hook) (cselib_val *);
  68 extern void (*cselib_record_sets_hook) (rtx insn, struct cselib_set *sets,
  69                                         int n_sets);
  70
  71 extern cselib_val *cselib_lookup (rtx, enum machine_mode,
  72                                   int, enum machine_mode);
  73 extern cselib_val *cselib_lookup_from_insn (rtx, enum machine_mode,
  74                                             int, enum machine_mode, rtx);
  75 extern void cselib_init (int);
  76 extern void cselib_clear_table (void);
  77 extern void cselib_finish (void);
  78 extern void cselib_process_insn (rtx);
  79 extern bool fp_setter_insn (rtx);
  80 extern enum machine_mode cselib_reg_set_mode (const_rtx);
  81 extern int rtx_equal_for_cselib_p (rtx, rtx);
  82 extern int references_value_p (const_rtx, int);
  83 extern rtx cselib_expand_value_rtx (rtx, bitmap, int);
  84 typedef rtx (*cselib_expand_callback)(rtx, bitmap, int, void *);
  85 extern rtx cselib_expand_value_rtx_cb (rtx, bitmap, int,
  86                                        cselib_expand_callback, void *);
  87 extern bool cselib_dummy_expand_value_rtx_cb (rtx, bitmap, int,
  88                                               cselib_expand_callback, void *);
  89 extern rtx cselib_subst_to_values (rtx, enum machine_mode);
  90 extern rtx cselib_subst_to_values_from_insn (rtx, enum machine_mode, rtx);
  91 extern void cselib_invalidate_rtx (rtx);
  92
  93 extern void cselib_reset_table (unsigned int);
  94 extern unsigned int cselib_get_next_uid (void);
  95 extern void cselib_preserve_value (cselib_val *);
  96 extern bool cselib_preserved_value_p (cselib_val *);
  97 extern void cselib_preserve_only_values (void);
  98 extern void cselib_preserve_cfa_base_value (cselib_val *, unsigned int);
  99 extern void cselib_add_permanent_equiv (cselib_val *, rtx, rtx);
 100 extern bool cselib_have_permanent_equivalences (void);
 101 extern void cselib_set_value_sp_based (cselib_val *);
 102 extern bool cselib_sp_based_value_p (cselib_val *);
 103
 104 extern void dump_cselib_table (FILE *);
 105
 106 /* Return the canonical value for VAL, following the equivalence chain
 107    towards the earliest (== lowest uid) equivalent value.  */
 108
 109 static inline cselib_val *
 110 canonical_cselib_val (cselib_val *val)
 111 {
 112   cselib_val *canon;
 113
 114   if (!val->locs || val->locs->next
 115       || !val->locs->loc || GET_CODE (val->locs->loc) != VALUE
 116       || val->uid < CSELIB_VAL_PTR (val->locs->loc)->uid)
 117     return val;
 118
 119   canon = CSELIB_VAL_PTR (val->locs->loc);
 120   gcc_checking_assert (canonical_cselib_val (canon) == canon);
 121   return canon;
 122 }