ptoulis's comment about stack-oriented loop structures got me thinking. What if the inner loop were replaced with individual lines of code? Here's what I came up with:

sub new {
    my $i = 0;
    while ($i += 20) {
        next if ($i % 1);
        next if ($i % 2);
        next if ($i % 3);
        next if ($i % 4);
        next if ($i % 5);
        next if ($i % 6);
        next if ($i % 7);
        next if ($i % 8);
        next if ($i % 9);
        next if ($i % 10);
        next if ($i % 11);
        next if ($i % 12);
        next if ($i % 13);
        next if ($i % 14);
        next if ($i % 15);
        next if ($i % 16);
        next if ($i % 17);
        next if ($i % 18);
        next if ($i % 19);
        print "Number: $i\n"; last;
    }
}
[download]

Then I benchmarked it against your original Perl code and got these results:

         s/iter original      new
original   25.7       --     -63%
new        9.57     168%       --
[download]

Admittedly, it doesn't scale very well and this example is very case specific, but I'll be paying closer attention to where and how I use loops from now on.

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