Comment # 68 on bug 64257 from Alex Deucher

Trig functions need slightly different setup on r6xx and r7xx+.  See
tgsi_setup_trig() in r600_shader.c:

/*
 * r600 - trunc to -PI..PI range
 * r700 - normalize by dividing by 2PI
 * see fdo bug 27901
 */