on x86_64:
        time    PSNR
plain   3.303   inf
SSE     1.649   107.087535
SSE3    1.632   107.087535
AVX     1.409   106.986771
FMA3    1.265   107.108437

on x86_32 (PSNR compared to x86_64 plain):
        time    PSNR
plain   7.225   103.951979
SSE     1.827   105.859282
SSE3    1.819   105.859282
AVX     1.533   105.997661
FMA3    1.384   105.885377

FMA4 test is not available
Reviewed-by: James Almer <jamrial@gmail.com>
Signed-off-by: Muhammad Faiz <mfcc64@gmail.com>