Just hours after Greg Giraldo passed away, one of his former Roast-mates -- Gilbert Gottfried -- was already making a joke out of the situation ... but did he go too far?!

Earlier today, Gottfried went to his Twitter page and wrote, "If Greg Giraldo is cremated, will that be the 'Greg Giraldo Roast'?"

We spoke to Gilbert about the tweet ... who told us he has problems expressing his emotions -- but noted, "Greg can't say anything about it now ... I'm not worried about him calling and complaining."