#!perl -w

use strict;
use Benchmark qw/ cmpthese /;

my $x = 'The Monastery Gates';
my $y = 'ThE MoNaStErY GaTeS';

cmpthese(-(shift),
         {
          eq => sub{ if (lc $x eq lc $y) {} },
          re => sub{ if ($x =~ /^$y$/i) {} },
         }
        )

__END__

Benchmark: running eq, re, each for at least 3 CPU seconds...
        eq:  6 wallclock secs ( 3.04 usr +  0.01 sys =  3.05 CPU) @ 242974.43/s
(n=741072)
        re:  8 wallclock secs ( 3.00 usr +  0.00 sys =  3.00 CPU) @ 86303.00/s (n=258909)
       Rate   re   eq
re  86303/s   -- -64%
eq 242974/s 182%   --