[turbofan] optimize moves into merges

src/compiler/move-optimizer.h

 // Copyright 2014 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_COMPILER_MOVE_OPTIMIZER_
 #define V8_COMPILER_MOVE_OPTIMIZER_
 
 #include "src/compiler/instruction.h"
 #include "src/zone-containers.h"
 
@@ skipping 12 matching lines @@
 
   InstructionSequence* code() const { return code_; }
   Zone* local_zone() const { return local_zone_; }
   Zone* code_zone() const { return code()->zone(); }
   MoveOpVector& temp_vector_0() { return temp_vector_0_; }
   MoveOpVector& temp_vector_1() { return temp_vector_1_; }
 
   void CompressBlock(InstructionBlock* blocke);
   void CompressMoves(MoveOpVector* eliminated, ParallelMove* left,
                      ParallelMove* right);
+  GapInstruction* LastGap(InstructionBlock* block);
+  void OptimizeMerge(InstructionBlock* block);
   void FinalizeMoves(GapInstruction* gap);
 
   Zone* const local_zone_;
   InstructionSequence* const code_;
   GapInstructions to_finalize_;
   MoveOpVector temp_vector_0_;
   MoveOpVector temp_vector_1_;
 
   DISALLOW_COPY_AND_ASSIGN(MoveOptimizer);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_MOVE_OPTIMIZER_