Why do I see a low fmax on a floating-point adder on Arria 10, even when the adder is fully pipelined?

Description

This problem affects DSP Builder designs targeting Arria 10 DSP blocks’ floating-point mode. You may see a long setup time on one of the input pins to the DSP block in SP_ADD mode as a ~2.5ns setup time for an input pin ax[30] on the DSP block. This setup time reduces fMAX below 276MHz..

Resolution

This problem has no workaround.