Isn't самое большее население the correct way to say "the biggest population"?

Question

I know that самое большо'е is the typical way to express the superlative (самый + positive).  But since большой is one of the "group of eight" adjecitves that form irregular comparisons, I thought it would be самое бо'льшее (самый + comparative).  Don't Russians use this construction anymore?