Due to a problem in the Intel® Quartus® Prime Pro Edition Software version 18.1 and earlier, you might see this internal error in the fitter plan stage when compiling an Intel® Stratix® 10 FPGA design with multiple instances of the ALTCLKCTRL Intel® FPGA IP. This error occurs when the clock gating feature is enabled and drives logic within a single I/O bank or transceiver tile.
Only one clock gate is supported within a single I/O bank or transceiver tile in Intel® Stratix® 10 devices.
To avoid the error, reduce the number of clock control blocks with clock gating feature enabled within a single I/O bank or transceiver tile to one.
This configuration is scheduled to provide a clear error message in a future release of the Intel® Quartus® Prime Pro Edition Software.