This problem affects DDR2, DDR3, and QDR II products.
For half-rate soft interfaces on Arria V and Cyclone V devices, the following warning might appear during the fitter phase:
Critical Warning (332168): The following clock transfers have no clock uncertainty assignment. For more accurate results, apply clock uncertainty assignments or use the derive_clock_uncertainty command.
The above warning applies to hold time uncertainty between the AFI clock domain and the address and command clock domain. You may ignore this warning.