SCEV: Don't assert about non-SCEV-able value in isSCEVExprNeverPoison() (PR28932)

Differential Revision: https://reviews.llvm.org/D23594

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@278999 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed