-new-struct-path-tbaa is work from ~6Y ago (although I think the discussion started ~10Y ago ) authored by @kosarev with fixes from ~1Y ago by @brunodf. It creates !tbaa metadata for structs and members where it wasn’t available before - in particular improving the optimizations for strong-typedefs, making them essentially zero-cost abstractions as they are advertised to be. Godbolt toy example here.
I really hope this work can stop hiding behind the -new-struct-path-tbaa switch. I built and tested some projects with it and personally I consider it stable. Is there any planned route forward with this?