Ex falso quodlibet.

Bounding UB would be a nice idea, or at least prohibiting time-traveling UB (and there is an effort in that direction). But properly specifing it is actually hard.

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account42 an hour ago | parent [-]

Prohibiting "time-travelling" UB would be horrible as that's a very important mechanism for dead code elimination.

	▲	dzaima 13 minutes ago \| parent [-]
		Even if you forbid "time travel", you can still technically optimize many things as if time travel happened anyway - e.g. want to time-travel back to before some memory store? just pretend that the store happened, but then afterwards the previous value was stored back (and no other threads happen to see the intermediate value)! Only things you need to worry about then are things with actual observable side-effects - volatile, printf and similar - and C23 does note that all observable behavior should happen even if UB follows, and compilers can't generally optimize function calls anyway (e.g. on systems on which you can define custom printf callbacks, you could put an exit(0) in such, and thus make it incorrect to optimize out a printf ever).