Bro, common sense. If the hiring manager mentioned to you (about increment upon confirmation) during your interview, you should ask after confirmation.

But if they said, your performance is not up to par, probably is time for you to look for a greener pasture while "slogging" with them.

There is no point asking if they didn't "promise" you that they will give you an increment after probation (or upon confirmation). They will give it to you when your performance proof to them that you are worth keeping. But if you do not intend to stay long with the company, no harm asking, since you got nothing to lose.