Great news from Valve. It seems they sponsored a new Mesa shader compiler for AMD gpus, called ACO. It is currently available for Arch based systems via AUR, and for Ubuntu based systems via PPAs. Others will need to compile from sources available on git.
I wonder if someone is willing to create and maintain a repo for openSUSE tumbleweed so that openSUSE users can help testing this without switching to other distributions.

Info Post:
Howto install: