Use bit fields to calculate compare stub minor key

src/x64/codegen-x64.cc

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 9087 matching lines @@
 }
 
 
 Handle<Code> GetBinaryOpStub(int key, BinaryOpIC::TypeInfo type_info) {
   GenericBinaryOpStub stub(key, type_info);
   return stub.GetCode();
 }
 
 
 int CompareStub::MinorKey() {
-  // Encode the three parameters in a unique 16 bit value.
+  // Encode the three parameters in a unique 16 bit value. To avoid duplicate
+  // stubs the never NaN NaN condition is only taken into account if the
+  // condition is equals.
   ASSERT(static_cast<unsigned>(cc_) < (1 << 14));
-  int nnn_value = (never_nan_nan_ ? 2 : 0);
-  if (cc_ != equal) nnn_value = 0;  // Avoid duplicate stubs.
-  return (static_cast<unsigned>(cc_) << 2) | nnn_value | (strict_ ? 1 : 0);
+  return ConditionField::encode(static_cast<unsigned>(cc_))
+         | StrictField::encode(strict_)
+         | NeverNanNanField::encode(cc_ == equal ? never_nan_nan_ : false);
 }
 
 
 const char* CompareStub::GetName() {
   switch (cc_) {
     case less: return "CompareStub_LT";
     case greater: return "CompareStub_GT";
     case less_equal: return "CompareStub_LE";
     case greater_equal: return "CompareStub_GE";
     case not_equal: {
@@ skipping 865 matching lines @@
   // Call the function from C++.
   return FUNCTION_CAST<ModuloFunction>(buffer);
 }
 
 #endif
 
 
 #undef __
 
 } }  // namespace v8::internal