1768afa5b9
It's portable, and useful to both Bifrost and Valhall, in the clause scheduler and in an instruction selection respectively. Move it from the Bifrost clause scheduler to common code so we can share the benefits. Signed-off-by: Alyssa Rosenzweig <alyssa@collabora.com> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16857>