[autojain]

What will happen if a Gasoline Engine is feeded with Diesel , what will be the effect on performance of engine? & vice versa

[CaptainRich]

Many, MANY, reasons, some of which:
Diesel fuel burns at a much different temperature and for very different reasons.
Fuel delivery systems are also totally different. Gasoline/petrol cars fuel pressure can be anywhere from as low as 5 psi to maybe 40-50 psi or so. (Varies significantly from one make to another.) However, diesel operating pressures can run into the thousands on some makes.
Anyone who has accidentally "blended" either way, or knows someone else who has, will attest that it creates numerous problems and clean-up can become equally expensive.