Question

What is the difference between O1, O2, Os, and O3 optimization in gcc?

Answer 1

O1 - O3 optimize for speed. Greater the number, greater the optimization. Os optimizes for size.

Answer 2

refer this http://www.linuxjournal.com/article/7269

Answer 3

So O2 is the one to generally pick?

Answer 4

na , you always try be with O3 but as no1 is perfect hence our bad code balances it and brings it to O2 LEVELS

Answer 5

I thought O3 optimization's space tradeoff outweighs the gains in speed, unlike O2.