A64: Synchronize with r15545.

src/hydrogen-dce.h

Index: src/hydrogen-dce.h
diff --git a/src/a64/debugger-a64.h b/src/hydrogen-dce.h
similarity index 78%
copy from src/a64/debugger-a64.h
copy to src/hydrogen-dce.h
index 50480cc268a49f53fafc1650e79d73de573524ed..19749f279a2e1cb632ba5a300033e5a9f038638f 100644
--- a/src/a64/debugger-a64.h
+++ b/src/hydrogen-dce.h
@@ -25,32 +25,32 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-#ifndef V8_A64_DEBUGGER_A64_H_
-#define V8_A64_DEBUGGER_A64_H_
+#ifndef V8_HYDROGEN_DCE_H_
+#define V8_HYDROGEN_DCE_H_
 
-#if defined(USE_SIMULATOR)
-
-#include "globals.h"
-#include "utils.h"
-#include "a64/constants-a64.h"
-#include "a64/simulator-a64.h"
+#include "hydrogen.h"
 
 namespace v8 {
 namespace internal {
 
 
-class Debugger : public Simulator {
+class HDeadCodeEliminationPhase : public HPhase {
  public:
-  Debugger(Decoder* decoder, FILE* stream = stdout)
-    : Simulator(decoder, NULL, stream) {}
-
-  // Functions overloading.
-  void VisitException(Instruction* instr);
+  explicit HDeadCodeEliminationPhase(HGraph* graph)
+      : HPhase("H_Dead code elimination", graph) { }
+
+  void Run() {
+    MarkLiveInstructions();
+    RemoveDeadInstructions();
+  }
+
+ private:
+  bool MarkLive(HValue* ref, HValue* instr);
+  void MarkLiveInstructions();
+  void RemoveDeadInstructions();
 };
 
 
 } }  // namespace v8::internal
 
-#endif  // USE_SIMULATOR
-
-#endif  // V8_A64_DEBUGGER_A64_H_
+#endif  // V8_HYDROGEN_DCE_H_