Summary: If the access is out of bounds, return UndefinedVal. If it is missing an explicit init, return the implicit zero value it must have.
Reviewers: NoQ, xazax.hun, george.karpenkov
Reviewed By: NoQ
Subscribers: szepet, rnkovacs, a.sidorin, cfe-commits
Differential Revision: https://reviews.llvm.org/D46823
llvm-svn: 333417