Simplify known successor block lowering.

src/x64/lithium-x64.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_X64_LITHIUM_X64_H_
 #define V8_X64_LITHIUM_X64_H_
 
 #include "hydrogen.h"
 #include "lithium-allocator.h"
 #include "lithium.h"
@@ skipping 2662 matching lines @@
         current_instruction_(NULL),
         current_block_(NULL),
         next_block_(NULL),
         allocator_(allocator) { }
 
   Isolate* isolate() const { return graph_->isolate(); }
 
   // Build the sequence for the graph.
   LPlatformChunk* Build();
 
-  LInstruction* CheckElideControlInstruction(HControlInstruction* instr);
-
   // Declare methods that deal with the individual node types.
 #define DECLARE_DO(type) LInstruction* Do##type(H##type* node);
   HYDROGEN_CONCRETE_INSTRUCTION_LIST(DECLARE_DO)
 #undef DECLARE_DO
 
   LInstruction* DoMathFloor(HUnaryMathOperation* instr);
   LInstruction* DoMathRound(HUnaryMathOperation* instr);
   LInstruction* DoMathAbs(HUnaryMathOperation* instr);
   LInstruction* DoMathLog(HUnaryMathOperation* instr);
   LInstruction* DoMathExp(HUnaryMathOperation* instr);
@@ skipping 131 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(LChunkBuilder);
 };
 
 #undef DECLARE_HYDROGEN_ACCESSOR
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::int
 
 #endif  // V8_X64_LITHIUM_X64_H_