C:\test>\perl5.18\bin\perl 1064178-b.pl
                Rate     OPdiff  using_vec hash_grep OPdiffModified OPdiff_undef
OPdiff         126/s         --       -22%      -31%           -43%         -44%
using_vec      162/s        28%         --      -12%           -26%         -28%
hash_grep      183/s        45%        13%        --           -17%         -19%
OPdiffModified 220/s        74%        36%       20%             --          -2%
OPdiff_undef   225/s        79%        39%       23%             2%           --