Function speedup (i7-6700)
Predictor  ssse3 v. C
4x4        ~2.1x
4x8        ~2.4x
8x4        ~4.1x
8x8        ~5.4x
8x16       ~6.1x
16x8       ~5.9x
16x16      ~6.4x
16x32      ~6.7x
32x16      ~7.4x
32x32      ~8.0x

Change-Id: I52b8ebf8193e76f4ea1137cbad5ad7fa109d86d8