Subzero: Prototype to make use of RegNumT::No Register more concise

src/IceTargetLoweringX8664Traits.h

 //===- subzero/src/IceTargetLoweringX8664Traits.h - x86-64 traits -*- C++ -*-=//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 383 matching lines @@
       return RegisterSet::Reg_ax;
     case IceType_i32:
       return RegisterSet::Reg_eax;
     case IceType_i64:
       return RegisterSet::Reg_rax;
     }
   }
 
 public:
   static RegNumT getGprForType(Type Ty, RegNumT RegNum) {
-    assert(RegNum != RegNumT::NoRegister);
+    assert(RegNum.hasValue());
 
     if (!isScalarIntegerType(Ty)) {
       return RegNum;
     }
 
     assert(Ty == IceType_i1 || Ty == IceType_i8 || Ty == IceType_i16 ||
            Ty == IceType_i32 || Ty == IceType_i64);
 
     if (RegNum == RegisterSet::Reg_ah) {
       assert(Ty == IceType_i8);
@@ skipping 617 matching lines @@
     const char *FldString;   // s, l, or <blank>
   } TypeAttributes[];
 };
 
 using Traits = ::Ice::X8664::TargetX8664Traits;
 } // end of namespace X8664
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICETARGETLOWERINGX8664TRAITS_H