This patch does two things:
- Adds support for part-word atomic instructions for Power7 (ISA 2.06) and Power8 (ISA 2.07)
- Adds the "lock" versions of all of the loads. These are the loads with the Exclusive Access hint bit set to 1
Atomic instructions in the IR will now use the part-word versions on platforms that support them (for types i8 and i16). The lock versions are only available through asm for now.