DeVault: Announcing the Hare programming language

That's exactly the kind of argument I was talking about in my last sentence that does not help these discussions. Somewhere along the way, someone put in a ton of work to write an optimisation pass to, I hope, produce more optimal output. Since everything is about optimising output, again, I would hope that there were at least *some* benchmarks published along with the new optimisation to show that maintaining the optimisation pass for the future is a good idea. Therefore when these discussions come up it should be pretty simple: "look, when this new NULL check deleting pass was added it brought X% to the table on this benchmark". At that point we would have a basis for discussion: maybe the code base in question isn't so important any more, maybe some other newer passes make the gains less relevant, or maybe just decide that the gains are not a good trade-off. With random hand-waiving and fear mongering there is no way a meaningful discussion can be had.

> At the end of that process, you can't just turn off one of the old compiler optimisations and expect to get meaningful results;

On the flip side optimisation passes can turn out to be meaningless because some other new passes don't create the sequences any more for it to be meaningful. It's also not like performance regressions are unheard of in compiler land. If we could have a discussion with numbers we could very well come to some tentative conclusion and disable the pass by default to see what falls out (let your users do the testing on "massive range of code bases").