[turbofan] small cleanups to aid register allocator debugging

src/compiler/register-allocator.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_REGISTER_ALLOCATOR_H_
 #define V8_REGISTER_ALLOCATOR_H_
 
 #include "src/compiler/instruction.h"
 #include "src/zone-containers.h"
 
@@ skipping 370 matching lines @@
   bool CanEagerlyResolveControlFlow(const InstructionBlock* block) const;
   bool SafePointsAreInOrder() const;
 
   // Liveness analysis support.
   void InitializeLivenessAnalysis();
   BitVector* ComputeLiveOut(const InstructionBlock* block);
   void AddInitialIntervals(const InstructionBlock* block, BitVector* live_out);
   bool IsOutputRegisterOf(Instruction* instr, int index);
   bool IsOutputDoubleRegisterOf(Instruction* instr, int index);
   void ProcessInstructions(const InstructionBlock* block, BitVector* live);
+  bool ExistsUseWithoutDefinition();
   void MeetRegisterConstraints(const InstructionBlock* block);
   void MeetConstraintsBetween(Instruction* first, Instruction* second,
                               int gap_index);
   void MeetRegisterConstraintsForLastInstructionInBlock(
       const InstructionBlock* block);
   void ResolvePhis(const InstructionBlock* block);
 
   // Helper methods for building intervals.
   InstructionOperand* AllocateFixed(UnallocatedOperand* operand, int pos,
                                     bool is_tagged);
@@ skipping 133 matching lines @@
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(RegisterAllocator);
 };
 
 }
 }
 }  // namespace v8::internal::compiler
 
 #endif  // V8_REGISTER_ALLOCATOR_H_