Comment # 1 on bug 101278 from nagrigoriadis@gmail.com

Apologies, I forgot some important related details:

I'm on kernel 4.11.1-gentoo right now, but observed the same on 4.10.8
libdrm-2.4.80
llvm-4.0.0-r2
xorg-server-1.19.3
xf86-video-ati-7.9.0
using the "radeon" kernel module.