BasicValueFactory: Add utility methods 'Add1' and 'Sub1' to get a persistent APSInt value that is 1 greater or 1 less than the provided value.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@64678 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed