gistfile1.txt

use strict;
use warnings;
use Benchmark qw(cmpthese);

my $regexp = qr/test/;
my @data = qw(Test foo Baz 2tesT);
my @lc_data = map { lc $_ } @data;

cmpthese -1 => {
    ignore => sub {
        $_ =~ /$regexp/i for @data;
    },
    lc => sub {
        lc($_) =~ /$regexp/ for @data;
    },
    non => sub {
        $_ =~ /$regexp/ for @data;
    },
    lc_data => sub {
        $_ =~ /$regexp/ for @lc_data;
    }
}, 'all';