r215614 - CodeGen: When bitfields fall on natural boundaries, split them up

[Rafael Espíndola]

> I think narrowing the loads and stores really needs to happen very late to
> maximize the information about the semantic model of the program in the IR.
> Now, this is predicated on us being *able* to do that narrowing. It was very
> easy in x86 (like, one tiny bug to fix, almost all of it "just worked") so
> I'm optimistic this is actually easy in general. Let me know if not though.

How late? Would a late IR pass be OK maybe?

Cheers
Rafael