[PATCH] Teach LoopIdiom about address spaces

[Eli Friedman]

  Isn't processLoopStridedStore missing a check so it doesn't try to generate memset_pattern16 in a non-zero address-space?  We can't assume all address-spaces are equivalent, even on OS X.  (Given that, the distinction between DestInt8PtrTy and SrcInt8PtrTy doesn't make sense.)

  Do we have test coverage for the memcpy case?

  Some of the testcases don't seem to be testing anything useful.

  Please commit the formatting change to the "if (SplatValue)" bit separately.

http://llvm-reviews.chandlerc.com/D1462