[llvm] [LLVM] Add option to store Parent-pointer in ilist_node_base (PR #94224)

[Duncan P. N. Exon Smith via llvm-commits]

https://github.com/dexonsmith commented:

I don't have time for a detailed review (travelling for the next few months)... but the plan in principle SGTM! Seems like a great way to detect the end iterator. Thanks for working on this. 

https://github.com/llvm/llvm-project/pull/94224