Can Quartus generate carry chains automatically?

Apparently Quartus isn't able to utilize the carry chain respectively LEs in arithmetic mode for synthesis, if the problem isn't presented in the expected way. I recently posted a small code example for demonstration: http://www.alteraforum.com/forum/showthread.php?t=27881

As already mentioned by Rysc, this isn't a problem for arithmetical problems, that are perfectly recognized by the Quartus synthesis. Except for educational purposes, there's no reasonable purpose to implement a low-level adder, I think. As my example shows, there are other problems, that could be considerably speeded up by using arithmetic mode, but apparently Quartus misses the chance.

P.S.: I forgot to mention, that a speedwise satisfying solution for the priority problem can be found using an adder, it's also suggested in the Stratix advanced synthesis cookbook. But it involves a doubled LE amount compared to a straightforward carry chain implementation.