Description
Due to a problem in the Quartus® Prime Pro Edition Software version 20.2 and earlier, you might see this internal error during compilation. This internal error might be seen when the design has an input buffer that fans out to more than one Double Data Rate I/O (DDIO).
Resolution
To work around this problem, change the design such that input buffer can fanout to only one DDIO.
This problem is fixed beginning with the Quartus® Prime Pro Edition Software version 20.3.