C:\test>\perl5.18\bin\perl.exe 1046579.pl -N=2**29
          s/iter      long   classic       str translate
long        3.92        --      -74%      -78%      -81%
classic     1.03      282%        --      -17%      -29%
str        0.847      363%       21%        --      -14%
translate  0.731      436%       40%       16%        --

C:\test>\perl5.18\bin\perl.exe 1046579.pl -N=2**30

Substitution loop at 1046579.pl line 42.