Just updated today and noticed a huge regression on X-Plane.
Mesa-git-87102.c45d84a works fine, but 87106.a7b510f causes the Sim frames to drop to 10 at certain areas.
I don't know how to bisect a git product, unfortunately, and the weather here in Brazil is hot and my processor would fry if I compiled for too long.
However, X-Plane offers a Free demo which you can try.
Downgraded to 87102.c45d84a for the time being.
Sapphire R9 270X
amdgpu Kernel driver (amd-staging-4.7)
Was the perf regression fixed in later Mesa releases?
No response from original reporter so closing bug.