provides a mechanism for optimizing compilers to select the different Register configuration.

src/compiler/instruction.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/compiler/common-operator.h"
 #include "src/compiler/graph.h"
 #include "src/compiler/instruction.h"
 #include "src/compiler/schedule.h"
 
 namespace v8 {
@@ skipping 254 matching lines @@
   // Do not record arguments as pointers.
   if (op.IsStackSlot() && StackSlotOperand::cast(op).index() < 0) return;
   DCHECK(!op.IsDoubleRegister() && !op.IsDoubleStackSlot());
   reference_operands_.push_back(op);
 }
 
 
 std::ostream& operator<<(std::ostream& os, const ReferenceMap& pm) {
   os << "{";
   bool first = true;
-  PrintableInstructionOperand poi = {RegisterConfiguration::ArchDefault(),
-                                     InstructionOperand()};
+  PrintableInstructionOperand poi = {
+      RegisterConfiguration::ArchDefault(RegisterConfiguration::TURBOFAN),
+      InstructionOperand()};
   for (auto& op : pm.reference_operands_) {
     if (!first) {
       os << ";";
     } else {
       first = false;
     }
     poi.op_ = op;
     os << poi;
   }
   return os << "}";
@@ skipping 589 matching lines @@
       os << " B" << succ.ToInt();
     }
     os << "\n";
   }
   return os;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8