Revert of Remove register index/code indirection

src/compiler/register-allocator-verifier.cc

 // 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.
 
 #include "src/bit-vector.h"
 #include "src/compiler/instruction.h"
 #include "src/compiler/register-allocator-verifier.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 200 matching lines @@
                       ? imm->inline_value()
                       : imm->indexed_value();
       CHECK_EQ(value, constraint->value_);
       return;
     }
     case kRegister:
       CHECK(op->IsRegister());
       return;
     case kFixedRegister:
       CHECK(op->IsRegister());
-      CHECK_EQ(RegisterOperand::cast(op)->GetDoubleRegister().code(),
-               constraint->value_);
+      CHECK_EQ(RegisterOperand::cast(op)->index(), constraint->value_);
       return;
     case kDoubleRegister:
       CHECK(op->IsDoubleRegister());
       return;
     case kFixedDoubleRegister:
       CHECK(op->IsDoubleRegister());
-      CHECK_EQ(DoubleRegisterOperand::cast(op)->GetDoubleRegister().code(),
-               constraint->value_);
+      CHECK_EQ(DoubleRegisterOperand::cast(op)->index(), constraint->value_);
       return;
     case kFixedSlot:
       CHECK(op->IsStackSlot());
       CHECK_EQ(StackSlotOperand::cast(op)->index(), constraint->value_);
       return;
     case kSlot:
       CHECK(op->IsStackSlot());
       return;
     case kDoubleSlot:
       CHECK(op->IsDoubleStackSlot());
@@ skipping 457 matching lines @@
         int virtual_register = op_constraints[count].virtual_register_;
         current->Define(zone(), instr->OutputAt(i), virtual_register);
       }
     }
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8