1 files changed, 121 insertions, 0 deletions
diff --git a/gcc/tree-ssa-scopedtables.h b/gcc/tree-ssa-scopedtables.h
index f7d9ca4..f37230e 100644
--- a/gcc/tree-ssa-scopedtables.h
+++ b/gcc/tree-ssa-scopedtables.h
@@ -20,6 +20,123 @@ along with GCC; see the file COPYING3.  If not see
 #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 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 ();
+
+  /* Record a single available expression that can be unwound.  */
+  void record_expr (expr_hash_elt_t, expr_hash_elt_t, char);
+
+ private:
+  vec<std::pair<expr_hash_elt_t, expr_hash_elt_t> > m_stack;
+  hash_table<expr_elt_hasher> *m_avail_exprs;
+
+  /* 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.
 
@@ -54,6 +171,10 @@ class const_and_copies
 
  private:
   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);
+
 #endif /* GCC_TREE_SSA_SCOPED_TABLES_H */