Merging r181579:

------------------------------------------------------------------------
r181579 | tstellar | 2013-05-09 19:09:39 -0700 (Thu, 09 May 2013) | 8 lines

R600: Expand SUB for v2i32/v4i32

Patch by: Aaron Watry

Reviewed-by: Tom Stellard <thomas.stellard@amd.com>
Signed-off-by: Aaron Watry <awatry@gmail.com>

NOTE: This is a candidate for the 3.3 branch.
------------------------------------------------------------------------


git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_33@181953 91177308-0d34-0410-b5e6-96231b3b80d8