I think it's custom to the PS4, although AMD have a habit of making all their custom work available to all customers (see all the non-x86/AMD64 OPs added to Phenom, Bulldozer etc.).
I don't think this is as much a performance feature as a programmability feature, to allow the ALMOST...
That's interesting because when the 8000M series were previewed, it was stated that the new GPU's had new compute features. Apparently that meant the 8700/8800/8900M asic's and not the 8500/8600M ones shipping now, but that was not made clear in the call.