[interpreter] Faster and fewer flushes in register optimizer.

src/interpreter/bytecode-register-optimizer.h

 // Copyright 2016 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_INTERPRETER_BYTECODE_REGISTER_OPTIMIZER_H_
 #define V8_INTERPRETER_BYTECODE_REGISTER_OPTIMIZER_H_
 
 #include "src/interpreter/bytecode-pipeline.h"
 
 namespace v8 {
@@ skipping 118 matching lines @@
   const Register temporary_base_;
 
   // Direct mapping to register info.
   ZoneVector<RegisterInfo*> register_info_table_;
   int register_info_table_offset_;
 
   // Counter for equivalence sets identifiers.
   int equivalence_id_;
 
   BytecodePipelineStage* next_stage_;
-  bool flushed_;
+  bool flush_required_;
   Zone* zone_;
 
   DISALLOW_COPY_AND_ASSIGN(BytecodeRegisterOptimizer);
 };
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_INTERPRETER_BYTECODE_REGISTER_OPTIMIZER_H_