XOR gate used in DFT compression logic

[barkha]

Why only XOR gate used in DFT compression logic ?

 

[yadavvlsi]

If we keep one input of XOR gate LOW than 2nd input will appears in output.(Buffer)
If we keep one input of XOR gate HIGH output will be inversion of second input.(Inverter)

So XOR gate provide controllability that one DFT's main requirement.

Also XOR gate can do comparison operation:
If both inputs are same it's output is 0. If both are different output is 1