On Fri, 30 Jul 2021, Mahmood Naderan via Gcc-help wrote:
I have noticed that my program with -O1 receives segmentation fault while if I manually specify all 45 O1 switches described in [1], the programs runs without problem. The gcc version is 9.3.0. I wonder if -O1 do something more than those switches.
https://gcc.gnu.org/wiki/FAQ#Is_-O1_.28-O2.2C-O3.2C_-Os_or_-Og.29_equivalent_to_individual_-foptimization_options.3F -- Marc Glisse
