[Turbofan] Add the concept of aliasing to RegisterConfiguration.

src/compiler/register-allocator-verifier.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_VERIFIER_H_
 #define V8_REGISTER_ALLOCATOR_VERIFIER_H_
 
 #include "src/zone-containers.h"
 
 namespace v8 {
@@ skipping 71 matching lines @@
   const InstructionBlock* origin() const { return origin_; }
   InstructionOperand operand() const { return operand_; }
 
  private:
   const InstructionBlock* const origin_;
   InstructionOperand operand_;
 
   DISALLOW_COPY_AND_ASSIGN(PendingAssessment);
 };
 
-// FinalAssessmens are associated to operands that we know to be a certain
+// FinalAssessments are associated to operands that we know to be a certain
 // virtual register.
 class FinalAssessment final : public Assessment {
  public:
   explicit FinalAssessment(int virtual_register,
                            const PendingAssessment* original_pending = nullptr)
       : Assessment(Final),
         virtual_register_(virtual_register),
         original_pending_assessment_(original_pending) {}
 
   int virtual_register() const { return virtual_register_; }
@@ skipping 154 matching lines @@
   ZoneMap<RpoNumber, DelayedAssessments*> outstanding_assessments_;
 
   DISALLOW_COPY_AND_ASSIGN(RegisterAllocatorVerifier);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif