How many GCC optimization levels are there?

Question

How many GCC optimization levels are there?

I tried gcc -O1, gcc -O2, gcc -O3, and gcc -O4

If I use a really large number, it won\'t work.

However, I

Answer 1

Four (0-3): See the GCC 4.4.2 manual. Anything higher is just -O3, but at some point you will overflow the variable size limit.