Summary: Added a test case just to make sure that isKnownNonZero() returns false when we cannot guarantee that a ConstantExpr is a non-zero constant. Reviewers: sanjoy, majnemer, mcrosier, nlewycky Subscribers: nlewycky, mssimpso, mcrosier, llvm-commits Differential Revision: http://reviews.llvm.org/D16908 llvm-svn: 260544