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 },
and here is the table I got (running under 5.8.0):
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%
+ --
Hugo