--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/tree-ssa-scopedtables.h	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,212 @@
+/* Header file for SSA dominator optimizations.
+   Copyright (C) 2013-2017 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#ifndef GCC_TREE_SSA_SCOPED_TABLES_H
+#define GCC_TREE_SSA_SCOPED_TABLES_H
+
+/* Representation of a "naked" right-hand-side expression, to be used
+   in recording available expressions in the expression hash table.  */
+
+enum expr_kind
+{
+  EXPR_SINGLE,
+  EXPR_UNARY,
+  EXPR_BINARY,
+  EXPR_TERNARY,
+  EXPR_CALL,
+  EXPR_PHI
+};
+
+struct hashable_expr
+{
+  tree type;
+  enum expr_kind kind;
+  union {
+    struct { tree rhs; } single;
+    struct { enum tree_code op;  tree opnd; } unary;
+    struct { enum tree_code op;  tree opnd0, opnd1; } binary;
+    struct { enum tree_code op;  tree opnd0, opnd1, opnd2; } ternary;
+    struct { gcall *fn_from; bool pure; size_t nargs; tree *args; } call;
+    struct { size_t nargs; tree *args; } phi;
+  } ops;
+};
+
+/* Structure for recording known value of a conditional expression.
+
+   Clients build vectors of these objects to record known values
+   that occur on edges.  */
+
+struct cond_equivalence
+{
+  /* The condition, in a HASHABLE_EXPR form.  */
+  struct hashable_expr cond;
+
+  /* The result of the condition (true or false.  */
+  tree value;
+};
+
+/* Structure for entries in the expression hash table.  */
+
+typedef class expr_hash_elt * expr_hash_elt_t;
+
+class expr_hash_elt
+{
+ public:
+  expr_hash_elt (gimple *, tree);
+  expr_hash_elt (tree);
+  expr_hash_elt (struct hashable_expr *, tree);
+  expr_hash_elt (class expr_hash_elt &);
+  ~expr_hash_elt ();
+  void print (FILE *);
+  tree vop (void) { return m_vop; }
+  tree lhs (void) { return m_lhs; }
+  struct hashable_expr *expr (void) { return &m_expr; }
+  expr_hash_elt *stamp (void) { return m_stamp; }
+  hashval_t hash (void) { return m_hash; }
+
+ private:
+  /* The expression (rhs) we want to record.  */
+  struct hashable_expr m_expr;
+
+  /* The value (lhs) of this expression.  */
+  tree m_lhs;
+
+  /* The virtual operand associated with the nearest dominating stmt
+     loading from or storing to expr.  */
+  tree m_vop;
+
+  /* The hash value for RHS.  */
+  hashval_t m_hash;
+
+  /* A unique stamp, typically the address of the hash
+     element itself, used in removing entries from the table.  */
+  struct expr_hash_elt *m_stamp;
+
+  /* We should never be making assignments between objects in this class.
+     Though it might allow us to exploit C++11 move semantics if we
+     defined the move constructor and move assignment operator.  */
+  expr_hash_elt& operator= (const expr_hash_elt&);
+};
+
+/* Hashtable helpers.  */
+
+struct expr_elt_hasher : pointer_hash <expr_hash_elt>
+{
+  static inline hashval_t hash (const value_type &p)
+    { return p->hash (); }
+  static bool equal (const value_type &, const compare_type &);
+  static inline void remove (value_type &element)
+    { delete element; }
+};
+
+
+/* This class defines a unwindable expression equivalence table
+   layered on top of the expression hash table.
+
+   Essentially it's just a stack of available expression value pairs with
+   a special marker (NULL, NULL) to indicate unwind points.   */
+
+class avail_exprs_stack
+{
+ public:
+  /* We need access to the AVAIL_EXPR hash table so that we can
+     remove entries from the hash table when unwinding the stack.  */
+  avail_exprs_stack (hash_table<expr_elt_hasher> *table)
+    { m_stack.create (20); m_avail_exprs = table; }
+  ~avail_exprs_stack (void) { m_stack.release (); }
+
+  /* Push the unwinding marker onto the stack.  */
+  void push_marker (void) { record_expr (NULL, NULL, 'M'); }
+
+  /* Restore the AVAIL_EXPRs table to its state when the last marker
+     was pushed.  */
+  void pop_to_marker (void);
+
+  /* Record a single available expression that can be unwound.  */
+  void record_expr (expr_hash_elt_t, expr_hash_elt_t, char);
+
+  /* Get the underlying hash table.  Would this be better as
+     class inheritance?  */
+  hash_table<expr_elt_hasher> *avail_exprs (void)
+    { return m_avail_exprs; }
+
+  /* Lookup and conditionally insert an expression into the table,
+     recording enough information to unwind as needed.  */
+  tree lookup_avail_expr (gimple *, bool, bool);
+
+  void record_cond (cond_equivalence *);
+
+ private:
+  vec<std::pair<expr_hash_elt_t, expr_hash_elt_t> > m_stack;
+  hash_table<expr_elt_hasher> *m_avail_exprs;
+
+  /* For some assignments where the RHS is a binary operator, if we know
+     a equality relationship between the operands, we may be able to compute
+     a result, even if we don't know the exact value of the operands.  */
+  tree simplify_binary_operation (gimple *, class expr_hash_elt);
+
+  /* We do not allow copying this object or initializing one
+     from another.  */
+  avail_exprs_stack& operator= (const avail_exprs_stack&);
+  avail_exprs_stack (class avail_exprs_stack &);
+};
+
+/* This class defines an unwindable const/copy equivalence table
+   layered on top of SSA_NAME_VALUE/set_ssa_name_value.
+
+   Essentially it's just a stack of name,prev value pairs with a
+   special marker (NULL) to indicate unwind points.  */
+
+class const_and_copies
+{
+ public:
+  const_and_copies (void) { m_stack.create (20); };
+  ~const_and_copies (void) { m_stack.release (); }
+
+  /* Push the unwinding marker onto the stack.  */
+  void push_marker (void) { m_stack.safe_push (NULL_TREE); }
+
+  /* Restore the const/copies table to its state when the last marker
+     was pushed.  */
+  void pop_to_marker (void);
+
+  /* Record a single const/copy pair that can be unwound.  This version
+     may follow the value chain for the RHS.  */
+  void record_const_or_copy (tree, tree);
+
+  /* Special entry point when we want to provide an explicit previous
+     value for the first argument.  Try to get rid of this in the future. 
+
+     This version may also follow the value chain for the RHS.  */
+  void record_const_or_copy (tree, tree, tree);
+
+ private:
+  /* Record a single const/copy pair that can be unwound.  This version
+     does not follow the value chain for the RHS.  */
+  void record_const_or_copy_raw (tree, tree, tree);
+
+  vec<tree> m_stack;
+  const_and_copies& operator= (const const_and_copies&);
+  const_and_copies (class const_and_copies &);
+};
+
+void initialize_expr_from_cond (tree cond, struct hashable_expr *expr);
+void record_conditions (vec<cond_equivalence> *p, tree, tree);
+
+#endif /* GCC_TREE_SSA_SCOPED_TABLES_H */