DC knowledge summary summary
1，group_path:
DC can be used group_path cost using different proportion at compile time.
The following command causes the compiler at compile time to the input port of the register, the register to the output port, the input port to the output port in case of doing three optimized separately.
group_path -name INPUT -from [all_inputs]
group_path -name OUTPUT -to [all_outputs]
group_path -name FEEDTHROUGH -from [all_inputs] -to [all_outputs]
Suppose register from the input port to the path timing slack is relatively large, when the DC integrated spend a lot of time to optimize this part of the logic, thus relaxing the optimization of register to register path. Group_path set these paths will be treated differently to give the same proportion of the cost of optimization.
