If the violation refers to a user clock, modify the constraints to remove the
create_clock constraint on the output of the CMB. If the
intention is to force the name of the auto-generated clock, AMD recommends using the create_generated_clock constraint with only the -name option and the CMB output pin. See the
Vivado Design Suite User Guide: Using
Constraints (UG903) for additional information about creating generated
clocks.
If the clock is generated by the Clocking Wizard, verify the setting for the . Use Single ended clock enabled pin when the input clock of the wizard is directly connected a top-level I/O port and Global Buffer when the input clock is coming from another Clocking Wizard instance.