Yes a pig will eat a human when the human is dead.
Pigs usually do not kill humans to eat them but if a person dies and is placed in a pig pen or the person dies while in the pig pen and the body is not removed quickly the pig or pigs will eat the human body.
There was a farmer in Oregon who died of a heart attack in the year 2012 and the pigs ate his body.
So yes pigs do eat humans if they are already dead.
Pigs will eat just about anything they can come across and if the pig is hungry enough it will eat your dead body.
However most pigs are not dangerous so there's no real worry about being killed or eaten alive by a pig but if you're already dead then the pig or pigs will usually eat the body.