Description
You might get this warning message if the PLL output clock(s) is not constrained properly in the SDC file.
Constrain all PLL output clocks in one of the following ways:
1. Use 'derive_pll_clocks' to automatically constrain the PLL output clocks, or
2. Use 'create_generated_clock' to constrain the PLL output clocks individually.
Refer to High-Performance FPGA PLL Analysis with TimeQuest (PDF) for further details about PLL analysis with TimeQuest.