array member of a struct, it's possible to land in an arbitrary position
inside that struct, such that attempting to find further getelementptr
indices will fail. In such cases, folding cannot be done.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79485 91177308-0d34-0410-b5e6-96231b3b80d8