Well, the PPE is a PowerPC as far as the ISA specifies--mostly--so the changes that have been wrought to support weakly consistent memory could help. But the Cell is so much more, from the locking caches in the PPE to the influence of the SPEs as they access shared Rambus memory. My guess is that you could compile it without too much hair, but tuning it for performance could require a lot of changes, even without dealing with the SPEs.
But who knows what you might discover and report back to this forum? I'd say go for it, and let us know what you find out.
