sub my_find_or_create {
  # ...
  my $existing_result = $self->find_by_something(@args);
  return $existing_result if (defined $existing_result);
  # ...
  return $new_result;
}

##</code><code>##

return $x if (defined (my $x=foo()));
# or
defined (my $x = foo()) && return $x;

##</code><code>##

if (defined (my $x=foo())) { return $x }