[Turbofan] Reduce register allocation work when we can.

src/compiler/instruction.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_COMPILER_INSTRUCTION_H_
 #define V8_COMPILER_INSTRUCTION_H_
 
 #include <deque>
 #include <iosfwd>
 #include <map>
@@ skipping 1371 matching lines @@
     return instruction_blocks_->at(rpo_number.ToSize());
   }
 
   InstructionBlock* GetInstructionBlock(int instruction_index) const;
 
   static MachineRepresentation DefaultRepresentation() {
     return MachineType::PointerRepresentation();
   }
   MachineRepresentation GetRepresentation(int virtual_register) const;
   void MarkAsRepresentation(MachineRepresentation rep, int virtual_register);
+  int representation_mask() const { return representation_mask_; }
 
   bool IsReference(int virtual_register) const {
     return CanBeTaggedPointer(GetRepresentation(virtual_register));
   }
   bool IsFP(int virtual_register) const {
     return IsFloatingPoint(GetRepresentation(virtual_register));
   }
-  bool IsFloat(int virtual_register) const {
-    return GetRepresentation(virtual_register) ==
-           MachineRepresentation::kFloat32;
-  }
-  bool IsDouble(int virtual_register) const {
-    return GetRepresentation(virtual_register) ==
-           MachineRepresentation::kFloat64;
-  }
 
   Instruction* GetBlockStart(RpoNumber rpo) const;
 
   typedef InstructionDeque::const_iterator const_iterator;
   const_iterator begin() const { return instructions_.begin(); }
   const_iterator end() const { return instructions_.end(); }
   const InstructionDeque& instructions() const { return instructions_; }
   int LastInstructionIndex() const {
     return static_cast<int>(instructions().size()) - 1;
   }
@@ skipping 97 matching lines @@
   Isolate* isolate_;
   Zone* const zone_;
   InstructionBlocks* const instruction_blocks_;
   SourcePositionMap source_positions_;
   ConstantMap constants_;
   Immediates immediates_;
   InstructionDeque instructions_;
   int next_virtual_register_;
   ReferenceMapDeque reference_maps_;
   ZoneVector<MachineRepresentation> representations_;
+  int representation_mask_;
   DeoptimizationVector deoptimization_entries_;
 
   // Used at construction time
   InstructionBlock* current_block_;
 
   DISALLOW_COPY_AND_ASSIGN(InstructionSequence);
 };
 
 
 struct PrintableInstructionSequence {
   const RegisterConfiguration* register_configuration_;
   const InstructionSequence* sequence_;
 };
 
 V8_EXPORT_PRIVATE std::ostream& operator<<(
     std::ostream& os, const PrintableInstructionSequence& code);
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_INSTRUCTION_H_