tr => q[
        ( my $revcmp = reverse $seq ) =~ tr[ACGTacgt][tgcaTGCA];
    ],

C:\test>junk60
             Rate     hdb atcroft  davido      tr
hdb        9827/s      --    -36%    -71%   -100%
atcroft   15292/s     56%      --    -55%    -99%
davido    33822/s    244%    121%      --    -99%
tr      2640400/s  26770%  17167%   7707%      --