(In reply to Nicolai Hähnle from comment #14)
> I suspect the reason that the blob drivers do it this way is that if you
> don't, you're likely to hit a subtle bug with emit inside control flow. And
> making the effort to exploit the undefined-ness probably pays off very
> rarely, so... I'm about to send out a patch to mesa-dev that might explain
> this better. In any case, the shader still did the wrong thing according to
> the spec :)

Following the spec fixed the problems I was seeing, thanks! It slightly slower
then on Windows, but within the same magnitude.

Cheers, Jakob.