It depends on approach.
For simple vermin eradication, anything that will put holes in pigs will do. The goal being death, not necessarily ethical dispatch.
If ethics or eating comes into it, 6.5 Grendel is where things really start. If night hunting with thermals, a low recoil 300 yard cartridge like 6.5 Grendel is pretty ideal. With IR and light gathering scopes, something in 7mm-30 cal is probably a little on the more forgiving side
If day hunting, walk up, stalking, line hunting, hard to beat a light, handy, lever gun in 30-30, 35 Rem, or 44 Mag, 45LC. If still hunting in the day, a bolt gun in anything from 6mm to 458 Win Mag.
Contrary to internet myth, hogs are no harder to kill than deer. But, if you want the body, you need to kill them fast because if they run in the habitats they live in, recovery becomes tricky if you give them 100 yards.