[turbofan] Initial import of SimplifiedOperatorReducer.

src/unique.h

 // Copyright 2013 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_HYDROGEN_UNIQUE_H_
 #define V8_HYDROGEN_UNIQUE_H_
 
 #include "src/handles.h"
 #include "src/objects.h"
 #include "src/string-stream.h"
@@ skipping 120 matching lines @@
 };
 
 
 // TODO(danno): At some point if all of the uses of Unique end up using
 // PrintableUnique, then we should merge PrintableUnique into Unique and
 // predicate generating the printable string on a "am I tracing" check.
 template <class T>
 class PrintableUnique : public Unique<T> {
  public:
   // TODO(titzer): make private and introduce a uniqueness scope.
+  PrintableUnique() : string_("null") {}
+
+  // TODO(titzer): make private and introduce a uniqueness scope.
   explicit PrintableUnique(Zone* zone, Handle<T> handle) : Unique<T>(handle) {
     InitializeString(zone);
   }
 
   // TODO(titzer): this is a hack to migrate to Unique<T> incrementally.
   PrintableUnique(Zone* zone, Address raw_address, Handle<T> handle)
       : Unique<T>(raw_address, handle) {
     InitializeString(zone);
   }
 
@@ skipping 253 matching lines @@
       }
       capacity_ = new_capacity;
       array_ = new_array;
     }
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_UNIQUE_H_