We know it's always a SCEVConstant if it gets here, so just cast it and
inline the only use of isNegative. Fixes warning reported by Mike Stump.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61600 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed