Squeeze the layout of expression nodes a bit.

src/ast.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_AST_H_
 #define V8_AST_H_
 
 #include "src/v8.h"
 
 #include "src/assembler.h"
@@ skipping 345 matching lines @@
   bool IsNullLiteral() const;
 
   // True if we can prove that the expression is the undefined literal.
   bool IsUndefinedLiteral(Isolate* isolate) const;
 
   // Expression type bounds
   Bounds bounds() const { return bounds_; }
   void set_bounds(Bounds bounds) { bounds_ = bounds; }
 
   // Whether the expression is parenthesized
-  unsigned parenthesization_level() const { return parenthesization_level_; }
-  bool is_parenthesized() const { return parenthesization_level_ > 0; }
-  void increase_parenthesization_level() { ++parenthesization_level_; }
+  bool is_parenthesized() const { return is_parenthesized_; }
+  bool is_multi_parenthesized() const { return is_multi_parenthesized_; }
+  void increase_parenthesization_level() {
+    is_multi_parenthesized_ = is_parenthesized_;
+    is_parenthesized_ = true;
+  }
 
   // Type feedback information for assignments and properties.
   virtual bool IsMonomorphic() {
     UNREACHABLE();
     return false;
   }
   virtual SmallMapList* GetReceiverTypes() {
     UNREACHABLE();
     return NULL;
   }
   virtual KeyedAccessStoreMode GetStoreMode() {
     UNREACHABLE();
     return STANDARD_STORE;
   }
 
   // TODO(rossberg): this should move to its own AST node eventually.
   virtual void RecordToBooleanTypeFeedback(TypeFeedbackOracle* oracle);
   byte to_boolean_types() const { return to_boolean_types_; }
 
   BailoutId id() const { return id_; }
   TypeFeedbackId test_id() const { return test_id_; }
 
  protected:
   Expression(Zone* zone, int pos, IdGen* id_gen)
       : AstNode(pos),
+        is_parenthesized_(false),
+        is_multi_parenthesized_(false),
         bounds_(Bounds::Unbounded(zone)),
-        parenthesization_level_(0),
         id_(id_gen->GetNextId()),
         test_id_(id_gen->GetNextId()) {}
   void set_to_boolean_types(byte types) { to_boolean_types_ = types; }
 
  private:
+  byte to_boolean_types_;
+  bool is_parenthesized_ : 1;
+  bool is_multi_parenthesized_ : 1;
   Bounds bounds_;
-  byte to_boolean_types_;
-  unsigned parenthesization_level_;
 
   const BailoutId id_;
   const TypeFeedbackId test_id_;
 };
 
 
 class BreakableStatement : public Statement {
  public:
   enum BreakableType {
     TARGET_FOR_ANONYMOUS,
@@ skipping 3139 matching lines @@
   Zone* zone_;
   Visitor visitor_;
   AstValueFactory* ast_value_factory_;
   AstNode::IdGen* id_gen_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_AST_H_