How to know which optimizations are turned on in gcc?

Question

I've seen that you can see the optimizations which are turned on using:

gcc -O2 -Q --help=optimizers

but the thing is that it only shows optimizations that have a flag.

Do you know if there's a way to find the others ?

This is maybe stupid since with no flag how would they describe the optimizations...but anyway...

Answer 1

Your best source of information may be the 'Optimize Options' section of the GCC manual.