my $var = do {
    my $temp1 = func1($a);
    my $temp2 = func2(++$a);
    $temp1 + $temp2;
  };

##</code><code>##

  my $var = func1($a) + func2($a + 1);

##</code><code>##

  my $var = do {
    my ($temp1, $temp2);
    my $thr1 = threads->new(sub { $temp1 = func1($a) })->start;
    my $thr2 = threads->new(sub { $temp2 = func2($a+1) })->start;
    $thr1->join;
    $thr2->join;
    $temp1 + $temp2
  };

##</code><code>##

  AUTOTHREADSUBEXPRS {
    $var = func1($a) + func2($a+1);
  }

##</code><code>##

  use threadedsubexprs;
  my $var = func1($a) + func2($a+1);