[PATCH] D14399: [X86][SSE] Combine UNPCKL with vector_shuffle into UNPCKH to save one instruction for sext from v16i8 to v16i16 and v8i16 to v8i32.

[Simon Pilgrim via llvm-commits]

RKSimon added a comment.

Please can you either add tests for 256-bit shuffles or (if you can't get this to occur) limit the combine to 128-bit vectors only?


http://reviews.llvm.org/D14399