Description
Due to a problem in the Quartus® II software version 12.1 and earlier, you may see this internal error when synthesizing a design targeting a Cyclone® V device with Physical Synthesis enabled and the Arria® V device libraries are not installed.
Resolution
To work around this problem, install the Arria V device libraries or disable Physical Synthesis.
This problem is fixed beginning with the Quartus II software version 12.1 SP1.