Provide a helper to generate multiple Lithium instructions for one Hydrogen instruction.

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 2788 matching lines @@
 
   // Marks a call for the register allocator.  Assigns a pointer map to
   // support GC and lazy deoptimization.  Assigns an environment to support
   // eager deoptimization if CAN_DEOPTIMIZE_EAGERLY.
   LInstruction* MarkAsCall(
       LInstruction* instr,
       HInstruction* hinstr,
       CanDeoptimize can_deoptimize = CANNOT_DEOPTIMIZE_EAGERLY);
 
   void VisitInstruction(HInstruction* current);
+  void CheckAndAddInstruction(LInstruction* instr, HInstruction* current);
 
   void DoBasicBlock(HBasicBlock* block, HBasicBlock* next_block);
   LInstruction* DoShift(Token::Value op, HBitwiseBinaryOperation* instr);
   LInstruction* DoArithmeticD(Token::Value op,
                               HArithmeticBinaryOperation* instr);
   LInstruction* DoArithmeticT(Token::Value op,
                               HBinaryOperation* instr);
   void FindDehoistedKeyDefinitions(HValue* candidate);
 
   LPlatformChunk* chunk_;
   CompilationInfo* info_;
   HGraph* const graph_;
   Status status_;
   HInstruction* current_instruction_;
   HBasicBlock* current_block_;
   HBasicBlock* next_block_;
   LAllocator* allocator_;
 
   DISALLOW_COPY_AND_ASSIGN(LChunkBuilder);
 };
 
 #undef DECLARE_HYDROGEN_ACCESSOR
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::int
 
 #endif  // V8_X64_LITHIUM_X64_H_