ison <ison@airmail.cc> writes:

> Sorry I neglected to mention that I actually tried upgrading mesa earlier and it
> didn't resolve the problem. Neither upgrading mesa (I tried 18.3.6 and some 19.*
> version) nor downgrading (back to 18.3.1) would fix it, all rebuilds still
> resulted in artifacts. I suppose it's because the dependency on llvm 7 remained
> fixed during all the rebuilds.
>
> I also just tried llvm 8.0.0 and it still had the same issue.

Can you try to delete "$HOME/.cache/mesa_shader_cache/" and see if see
if it makes a difference?