> It is possible in theory that code that’s less carefully optimized exhibits different behavior, or that the benchmarks chosen here are simply not as amenable

> It is possible in theory that code that’s less carefully optimized exhibits different behavior, or that the benchmarks chosen here are simply not as amenable to compiler optimization as they could be I think that's very relevant. A lot of compiler optimisation work is about allowing programmers to write more natural code without losing efficiency. That won't show up as a speed gain in cases where the programmers were writing the "low level" form in the first place.