Note that -Os and -Oz often give you faster code than -O2. Also -O3 doesn't turn on all optimizations. (Most notably, -O3 won't omit the frame pointer for lea

Note that -Os and -Oz often give you faster code than -O2. Also -O3 doesn't turn on all optimizations. (Most notably, -O3 won't omit the frame pointer for leaf calls. Yes, omitting the frame pointer can make debugging harder.)