https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97553
--- Comment #3 from Eyal Rozenberg <eyalroz at technion dot ac.il> --- > And, the runtime sanitization intentionally isn't heavily optimized away, > because the intent is to detect when the code is invalid, so it can't e.g. > optimize away those checks based on assumption that undefined behavior will > not happen. So, doesn't that essentially mean that -O3 cannot properly apply with UBsan?