Select Code to Download

use strict;
use Benchmark qw(cmpthese);
...
  'i'       => sub { $text =~ /abc/ig },
  'chars'   => sub { $text =~ /[Aa][Bb][Cc]/g },
});

Benchmark: timing 10 iterations of chars, i...
     chars: 40 wallclock secs (38.37 usr +  0.04 sys = 38.41 CPU) @  0
+.26/s (n=10)
...
      s/iter chars     i
chars   3.84    --  -70%
i       1.14  236%    --