[CodeGen] Fix warning in changeVectorElementTypeToInteger

[david-arm]

Summary

When creating vectors with MVT::getVectorVT we should be using
getVectorElementCount() instead of getVectorNumElements().

[dancgr]

Hello David, I have this patch here that I was going to upstream (https://reviews.llvm.org/D80746), but I just realized that it is exactly the same as this one.

I just wanted to ask if you think it is OK that we merge it, since is the same line from this patch.

[david-arm]

Hi @dancgr, sure I'm happy for you to submit your patch (https://reviews.llvm.org/D80746) instead!

llvm/include/llvm/CodeGen/ValueTypes.h

public:
     /// with the element type converted to an integer type with the same
     /// bitwidth.
     EVT changeVectorElementTypeToInteger() const {
       if (!isSimple())
         return changeExtendedVectorElementTypeToInteger();
       MVT EltTy = getSimpleVT().getVectorElementType();
       unsigned BitWidth = EltTy.getSizeInBits();
       MVT IntTy = MVT::getIntegerVT(BitWidth);
-      MVT VecTy = MVT::getVectorVT(IntTy, getVectorNumElements(),
-                                   isScalableVector());
+      MVT VecTy = MVT::getVectorVT(IntTy, getVectorElementCount());
       assert(VecTy.SimpleTy != MVT::INVALID_SIMPLE_VALUE_TYPE &&
              "Simple vector VT not representable by simple integer vector VT!");
       return VecTy;
     }
 
     /// Return the type converted to an equivalently sized integer or vector
     /// with integer element type. Similar to changeVectorElementTypeToInteger,
     /// but also handles scalars.