[PATCH] Fix SROA creating invalid bitcasts between address spaces

[Matt Arsenault]

  Thanks for the review! Some of the pieces aren't supposed to be strictly necessary. I'm also trying to get rid of the default address space arguments, and it seems like a better idea to do the consistent thing and get the address space from the value rather than hardcoding to 0 since you know it's an alloca derived pointer. I'll work on updating the tests tomorrow

http://llvm-reviews.chandlerc.com/D1764