I am having Warnings after CTS,Route and PostRoute opt
WARNING (NRDB-51) SPECIAL_NET SG_rr is empty with no instance pin and special wire. Net with the same name will be routed but will not be connecte to the empty SPECIAL_NET.
The SG_rr net is too long and having approx. 30ns net delay.
By observing this I found that this net is HFN, ...