Is there a spell in the Pathfinder world that grants a power to melee or ranged weapons similar to the Smite Evil / Smite Good ability to overcome all forms of Damage Reduction?
To clarify, here is the Smite Evil ability of the Paladin.
It sounds like you want a spell that effectively mimics this part of the ability.
If you look at the section on Damage Reduction, you will see there is a segment on "Overcoming DR". This states:
Any weapon with an Enhancement bonus of +5 ignores all Damage Reduction except for DR/-. Note that this only seems to work if the weapon is permanently enchanted, a weapon temporarily enchanted with the Magic Weapon spell can only bypass DR/magic.
Aside: there are two spells to help you bypass specific forms of resistance. But neither of these bypass DR/-
But none of these beat DR/-. Yep, as far as I can tell, only that Smite ability is capable of completely ignoring DR all together. Worth knowing next time you face the Tarrasque :)