Properly handle cases where a predecessor of the block being queried on is unreachable.
This fixes PR2503, though we should also fix other passes not to emit this kind of code.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52946 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed