radeonsi: use guard band clipping

Guard band clipping speeds up rasterization for primitives that are
partially off-screen.  This change in particular results in small
framerate improvements in a wide range of games.

Started by Grigori Goronzy <greg@chown.ath.cx>.

Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-by: Grigori Goronzy <greg@chown.ath.cx>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
1 file changed