clobber with the current implementation. Instead of returning
a "precise clobber" just return a fuzzy one. This doesn't
matter to any clients anyway and should speed up analysis time
very very slightly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60641 91177308-0d34-0410-b5e6-96231b3b80d8