Add missing -*- C++ -*- to headers

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182164 91177308-0d34-0410-b5e6-96231b3b80d8
Replace redundant code

Use EVT::changeExtendedVectorElementTypeToInteger instead of doing the
same thing that it does

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182165 91177308-0d34-0410-b5e6-96231b3b80d8