[SelectionDAG] Don't call GetWidenedVector for mask operands of MLOAD/MSTORE.

GetWidenedVector does't guarantee the widened elements are zero which would break the intended behavior of the operation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319849 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed