use Regexp::Optimizer qw( );
my $o = Regexp::Optimizer->new();
print $o->optimize(qr/123*/),  "\n";  # (?-xism:123*)
print $o->optimize(qr/1233*/), "\n";  # (?-xism:1233*)
print $o->optimize(qr/123+/),  "\n";  # (?-xism:123+)