cmpthese(-5, {
  last => sub { my $x = $str; $x =~ s/([A-Z])[^A-Z]*$/$1/ },
  capt_repl => sub { my $x = $str; $x =~ s/(.*[A-Z]).*/$1/ },
  rx_rx => sub { my $x = $str; $x =~ /.*[A-Z]/g and $x =~ s/\G.*// },
  sexeger => sub {
    my $x = $str; ($x = reverse $x) =~ s/^[^A-Z]+//; $x = reverse $x;
  },
});

__END__
             Rate      last capt_repl     rx_rx   sexeger
last       5591/s        --      -82%      -86%      -86%
capt_repl 30599/s      447%        --      -21%      -24%
rx_rx     38948/s      597%       27%        --       -3%
sexeger   40049/s      616%       31%        3%        --