Windows 7 x64, RX480 with Crimson 17.3.1
Broken: latest master 96868a3
Short description of error
AO bounce approximation gives good speedup and visible differences with CPU, but with GPU the image and render time seem to stay the same as without the simplification.
Exact steps for others to reproduce the error
Open attached .blend:
This is the result with CPU (correct):
and this is with GPU: