Timing Constraint problem on set_input_delay

Thank you very much for your reply.I did timing constraint using a way like the option 2.

I used constraint set_output_delay -clock virt_clk -max 0 [get_ports A[*]] to get the

max tCO of the A.Then,I calculated the max tCO of the D for the SysClk.And using this way,I worried I forgot to change the calculated value if the tCO of A changed.

So then I wanted to use the way with reference_pin.But using the option2 of you,I think there is no necessary to worry about that.

By the way,I used the first way to do timing constraint.And I found that the data path doesn't calculate in the tCO of A.So I thought that there is something wrong

with it.Right?