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      1 /* Routines for expanding from SSA form to RTL.
      2    Copyright (C) 2009-2022 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
      7 it under the terms of the GNU General Public License as published by
      8 the Free Software Foundation; either version 3, or (at your option)
      9 any later version.
     10 
     11 GCC is distributed in the hope that it will be useful,
     12 but WITHOUT ANY WARRANTY; without even the implied warranty of
     13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     14 GNU General Public License 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 
     21 #ifndef GCC_TREE_OUTOF_SSA_H
     22 #define GCC_TREE_OUTOF_SSA_H
     23 
     24 
     25 /* This structure (of which only a singleton SA exists) is used to
     26    pass around information between the outof-SSA functions, cfgexpand
     27    and expand itself.  */
     28 struct ssaexpand
     29 {
     30   /* The computed partitions of SSA names are stored here.  */
     31   var_map map;
     32 
     33   /* For an SSA name version V bit V is set iff TER decided that
     34      its definition should be forwarded.  */
     35   bitmap values;
     36 
     37   /* For a partition number I partition_to_pseudo[I] contains the
     38      RTL expression of the allocated space of it (either a MEM or
     39      a pseudos REG).  */
     40   rtx *partition_to_pseudo;
     41 
     42   /* If partition I contains an SSA name that has a default def for a
     43      parameter, bit I will be set in this bitmap.  */
     44   bitmap partitions_for_parm_default_defs;
     45 
     46   /* If partition I contains an SSA name that has an undefined value,
     47      bit I will be set in this bitmap.  */
     48   bitmap partitions_for_undefined_values;
     49 };
     50 
     51 /* This is the singleton described above.  */
     52 extern struct ssaexpand SA;
     53 
     54 /* Returns the RTX expression representing the storage of the outof-SSA
     55    partition that the SSA name EXP is a member of.  */
     56 static inline rtx
     57 get_rtx_for_ssa_name (tree exp)
     58 {
     59   int p = partition_find (SA.map->var_partition, SSA_NAME_VERSION (exp));
     60   if (SA.map->partition_to_view)
     61     p = SA.map->partition_to_view[p];
     62   gcc_assert (p != NO_PARTITION);
     63   return SA.partition_to_pseudo[p];
     64 }
     65 
     66 /* If TER decided to forward the definition of SSA name EXP this function
     67    returns the defining statement, otherwise NULL.  */
     68 static inline gimple *
     69 get_gimple_for_ssa_name (tree exp)
     70 {
     71   int v = SSA_NAME_VERSION (exp);
     72   if (SA.values && bitmap_bit_p (SA.values, v))
     73     return SSA_NAME_DEF_STMT (exp);
     74   return NULL;
     75 }
     76 
     77 extern bool ssa_is_replaceable_p (gimple *stmt);
     78 extern void finish_out_of_ssa (struct ssaexpand *sa);
     79 extern unsigned int rewrite_out_of_ssa (struct ssaexpand *sa);
     80 extern void expand_phi_nodes (struct ssaexpand *sa);
     81 
     82 #endif /* GCC_TREE_OUTOF_SSA_H */
     83