Using an inappropriately sized weapon confers a penalty to hit, as follows:
Inappropriately Sized Weapons: A creature can't make optimum use of a
weapon that isn't properly sized for it. A cumulative –2 penalty
applies on attack rolls for each size category of difference between
the size of its intended wielder and the size of its actual wielder.
If the creature isn't proficient with the weapon, a –4 nonproficiency
penalty also applies.
I know that the Titan Mauler's Massive Grip ability reduces that penalty by 1 for every 3 levels.
Are there any other traits, feats, or class abilities that can reduce the penalty to hit from an inappropriately sized weapon?