gistfile1.txt

#!/usr/bin/perl

use strict;
use warnings;

use Benchmark;

my $r;
my @a = qw/ aaa bbb aaa bbb aaa /;
my @b = qw/ fff fff fff fff fff /;
Benchmark::cmpthese -1, {
	diff => sub { 
		for my $s (@a) {
			$r = qr/$s/;
		}
	},
	same => sub { 
		for my $s (@b) {
			$r = qr/$s/;
		}
	},
};