use strict;
use warnings;
use Benchmark;

our @strings = qw(exception:tex exception:mex asdf tex:exception:mex);

Benchmark::cmpthese( -5, {
    'one'   => q[ my @filtered = grep { /exception:(?!tex)/} @strings; ],
    'two'   => q[ my @filtered = grep { /exception/ && !/tex/ } @strings; ],
    'three' => q[ my @filtered = grep { /exception:/g && !/\Gtex/ } @strings; ],
});
__END__
          Rate   one   two three
one   127000/s    --  -21%  -22%
two   161678/s   27%    --   -1%
three 163855/s   29%    1%    --