use strict;
use warnings;

use Benchmark qw(cmpthese);

print "perl version $] \n";

my $rx = qr{X}xms;

cmpthese(-1, {
    'qr_bound'    => sub { 'Y' =~   $rx   ; },
    'qr_interp'   => sub { 'Y' =~ / $rx / ; },
    'qr_interp_o' => sub { 'Y' =~ / $rx /o; },
    'm_empty'     => sub { 'Y' =~ //;       },
    'm_empty_o'   => sub { 'Y' =~ //o;      },
    });

##</code><code>##

c:\@Work\Perl\monks\belg4mit>perl cmp_qr_compilation_1.pl
perl version 5.008009
                 Rate   qr_interp qr_interp_o    qr_bound     m_empty  m_empty_o
qr_interp   2880477/s          --         -9%        -43%        -55%       -67%
qr_interp_o 3181791/s         10%          --        -37%        -51%       -64%
qr_bound    5078627/s         76%         60%          --        -21%       -42%
m_empty     6452035/s        124%        103%         27%          --       -26%
m_empty_o   8775008/s        205%        176%         73%         36%         --

c:\@Work\Perl\monks\belg4mit>perl cmp_qr_compilation_1.pl
perl version 5.014004
                  Rate    qr_bound  qr_interp     m_empty  m_empty_o qr_interp_o
qr_bound     1004609/s          --       -70%        -76%       -80%        -92%
qr_interp    3378700/s        236%         --        -20%       -33%        -74%
m_empty      4237856/s        322%        25%          --       -16%        -68%
m_empty_o    5068698/s        405%        50%         20%         --        -61%
qr_interp_o 13135439/s       1208%       289%        210%       159%          --