return values. Now the base class of the value hierarchy is "ValueBase"
instead of "Value", and "Value" is now a PointerIntPair indicating the
ValueBase (e.g. an instruction) being referenced along with what result
value is being referenced.
By default, any place you used "Value*" before, you should now use "Value".
Swift SVN r3207
Add RetainInst, ReleaseInst, DeallocInst for managing object lifetimes, and CopyInst and DestroyInst for indirectly managing resilient types and other non-materializable types.
Swift SVN r3159
