Description
Due to a problem in the Intel® Stratix® 10 device simulation model in the Intel® Quartus® Prime Pro Edition software version 19.1 and earlier, you may see unknown (x) MLAB RAM output values in gate-level simulation with the VHDL netlist (*.vho).
Resolution
To work around this problem, use the Verilog netlist (*.vo) for MLAB RAM in the gate-level simulation.
This problem is scheduled to be fixed in a future release of the Intel® Quartus® Prime Pro Edition software.