More details definitely needed. What's your target device? What are the parameters for your EMIF? Hard or soft implementation (device-dependent)? Stand-alone IP or are you implementing it in a system in Platform Designer? Etc.
You do not want to false path this if it's a transfer between the core and the interface, so you need to find the root of the violation.
1. My target device is DDR4 Hilo module on arria 10 FPGA.
2. The EMIF parameter is follow standard DDR4 Hilo module type.
3. Hard IP for implementation.
4. I designed a system with EMIF DDR4 IP.
I think the emif user clock is only for others FPGA elements using because there is fifo between the emif user clock and emif phy clock. So they do not have any relationship. Is it right?