http://www.d20pfsrd.com/feats/general-feats/fiendish-heritage
Specifically:
16. You have oversized limbs, allowing you to use Large weapons without penalty.
Does this allows you to wield large weapons of all types? Or just the regular oversized 1 handed weapons?
As worded, it should remove the over-sized weapon penalties from wielding any Large weapon - ranged, light, one-, or two-handed.