Question

I found a lot of Optimization Options here

While going through them I found some of them have side-effects (like makes debugging impossible). In my experience I have found the -O1 to -O3 and -Os most commonly used. But, what are the other options which are commonly used in your projects?

Answer 1

-ffast-math can have a significant performance impact on floating point intensive software.

Also, compiling specific for the target processor using the appropriate -march= option may have a slight performance impact, but strictly speaking, this is not an optimizing option.