Fix Known Issues Quartus QSYS regenerating error
From Terasic Wiki
Since the Qsys tool of the Quartus version 20.1.1 lacks some library files, this will cause users to encounter errors when regenerating their Qsys project.
Figure 1 QSYS
The solution is to copy the ip_compiler_for_pci_express folder from the \System CD\Demonstrations\PCIE_DDR3 or PCIE_Fundamental to : \Your Host\<Quartus_install_path>\ip\altera\, For example : D:\intelFPGA\20.1\ip\altera\
