https://bugs.freedesktop.org/show_bug.cgi?id=93767
--- Comment #6 from Daniel Scharrer daniel@constexpr.org --- Hi, thanks for looking into this.
The problem happens on all MSAA levels the game offers: 2, 4 and 6 (I assume this maps to 8). The there are less lines with lower MSAA levels though, or at least they are less noticeable.
R600_DEBUG=nohyperz does get rid of the glitches for all MSAA levels.