Just for the record: firstly, it used to be that even simplistic sort subs such as { $a <=> $b } would call out to perl code, but that was changed to look for certain common cases and substitute a C implementation instead; I think that change first appeared in 5.6.1, judging by comparative timings here.

Secondly, the bug in B::Deparse (which occurred simply because it wasn't immediately updated for the above change) was fixed in perl-5.8.0.

Just to give a feel for the difference it makes spotting and substituting a C-based routine for a perl-based one, I added an extra variant of i_sship tweaked to avoid the optimization:

  i_sshipz => sub { @rin = sort { $a + 0 <=> $b } @nin },
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            Rate i_sshipz  f_owtdi  i_owtdi  f_alpha  i_alpha  f_sship
+  i_sship
i_sshipz  16.5/s       --     -27%     -28%     -43%     -52%     -57%
+     -58%
f_owtdi   22.6/s      37%       --      -1%     -22%     -34%     -41%
+     -42%
i_owtdi   22.8/s      38%       1%       --     -21%     -33%     -41%
+     -41%
f_alpha   29.0/s      76%      28%      27%       --     -15%     -25%
+     -26%
i_alpha   34.2/s     107%      51%      50%      18%       --     -11%
+     -12%
f_sship   38.5/s     134%      70%      69%      33%      13%       --
+      -1%
i_sship   38.9/s     136%      72%      71%      34%      14%       1%
+       --
[download]