> But that’s a lot of work to save a byte or two. Is it? It's something like two xors on a register. If that's a byte or two per pointer (ie: it's pointer meta

> But that’s a lot of work to save a byte or two. Is it? It's something like two xors on a register. If that's a byte or two per pointer (ie: it's pointer metadata that you'd have to store anyway, which I assume is the use case) that's actually a pretty significant win, and could help reduce cache pressure, thereby buying you back the performance (and then some). Addresses are also XOR'd all the time with a secret as a mitigation, I don't know that there's much of an impact at all.