Forum Discussion
Your understanding is correct, the Plan stages—places all periphery elements (such as I/Os and PLLs) and determines a legal clock plan, without core placement or routing.
With 15 hours on Plan Stage, something might have gone wrong with your design. Even 2-3 hours is consider long. Try to isolate your design by uncomment the instantiation of the design modules or removing portions of RTL code.
If the time reduces significantly, this might indicates that the issue lies within the commented-out portion of the design.
Perhaps you may check the what are the differences between these two designs (15 hrs vs 2/3 hrs) that might indicate so. Different IP usage, design constraints, etc.
Alternatively, you may opt to upgrade your design to the latest Quartus version and see if the time improves.
Regards,
Richard Tan