Division by 2 is one of the quickest operation. The correct implies 3 additions instead of one, so you go a point. But y>>1 + x>>1 + (x & y & 1) is easier to

Division by 2 is one of the quickest operation. The correct implies 3 additions instead of one, so you go a point. But y>>1 + x>>1 + (x & y & 1) is easier to remember than ((x^y)>>1) + (x&y).