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

src/IceTargetLoweringMIPS32.cpp

Index: src/IceTargetLoweringMIPS32.cpp
diff --git a/src/IceTargetLoweringMIPS32.cpp b/src/IceTargetLoweringMIPS32.cpp
index e34dd5d86c675ed01d2129c57e1aaa0bb63088f3..c6d39cf45866b4fa2ccd51c4326f92b7e5f9088d 100644
--- a/src/IceTargetLoweringMIPS32.cpp
+++ b/src/IceTargetLoweringMIPS32.cpp
@@ -360,7 +360,7 @@ Variable *TargetMIPS32::makeReg(Type Type, RegNumT RegNum) {
   // There aren't any 64-bit integer registers for Mips32.
   assert(Type != IceType_i64);
   Variable *Reg = Func->makeVariable(Type);
-  if (RegNum == RegNumT::NoRegister)
+  if (RegNum.noRegister())
     Reg->setMustHaveReg();
   else
     Reg->setRegNum(RegNum);