The p<n>_app_clk (where n=1,2,3,4) is the correct clock to use as the application clock for the Intel® FPGA P-Tile Avalon® Memory-mapped IP for PCI Express*. The Intel® FPGA P-Tile Avalon® Memory-mapped IP for PCI Express* User Guide revision UG-20237 | 2020.11.17, incorrectly refers to coreclkout_hip as the application clock. Similarly the Intel® FPGA P-Tile Avalon® Memory-mapped IP for PCI Express* currently generates a top level coreclkout_hip port which should not be used as the application clock.
The Intel® FPGA P-Tile Avalon® Memory-mapped IP for PCI Express* User Guide and the IP top level RTL are scheduled to be updated in the future release of the document and the IP.