The FBW Airbus types have combined Air Data Computer and Inertial Reference Systems, but the speed indicated to the pilots is effectively Calibrated Air Speed derived from the pressute data from the pitots. The very latest ones come with the BUSS (Back Up Speed Scale) where is the ADRs fail or there is a major discrepancy in the indication, the can indicate a speed and altitude reference which is derived from the GPS. I've tried it in the simulator and it works very well.