GCC Middle and Back End API Reference
tree-outof-ssa.h
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1 /* Routines for expanding from SSA form to RTL.
2  Copyright (C) 2009-2013 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,
43  bit I will be set in this bitmap. */
44  bitmap partition_has_default_def;
45 };
46 
47 /* This is the singleton described above. */
48 extern struct ssaexpand SA;
49 
50 /* Returns the RTX expression representing the storage of the outof-SSA
51  partition that the SSA name EXP is a member of. */
52 static inline rtx
53 get_rtx_for_ssa_name (tree exp)
54 {
55  int p = partition_find (SA.map->var_partition, SSA_NAME_VERSION (exp));
56  if (SA.map->partition_to_view)
57  p = SA.map->partition_to_view[p];
58  gcc_assert (p != NO_PARTITION);
59  return SA.partition_to_pseudo[p];
60 }
61 
62 /* If TER decided to forward the definition of SSA name EXP this function
63  returns the defining statement, otherwise NULL. */
64 static inline gimple
65 get_gimple_for_ssa_name (tree exp)
66 {
67  int v = SSA_NAME_VERSION (exp);
68  if (SA.values && bitmap_bit_p (SA.values, v))
69  return SSA_NAME_DEF_STMT (exp);
70  return NULL;
71 }
72 
73 extern bool ssa_is_replaceable_p (gimple stmt);
74 extern void finish_out_of_ssa (struct ssaexpand *sa);
75 extern unsigned int rewrite_out_of_ssa (struct ssaexpand *sa);
76 extern void expand_phi_nodes (struct ssaexpand *sa);
77 
78 #endif /* GCC_TREE_OUTOF_SSA_H */