used uninitialized, since it fails to understand that Array is only used when
SingleValue is not, and outputs a warning. It also seems generally safer given
that the constructor is non-trivial and has plenty of early exits.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173242 91177308-0d34-0410-b5e6-96231b3b80d8