The problem is the code unconditionally dereferences the pointer, which would be UB if it was a null pointer. This means it is legal to optimize out any code paths that rely on this, even if they occur earlier in program order.
When NDEBUG is set, there is no test, no assertion, at all. So yes, this code has UB if you set NDEBUG and then pass it a null pointer — but that's obvious. The code does exactly what it looks like it does; there's no tricks or time travel hiding here.
Right so strictly speaking C++ could do anything here when passed a null pointer, because even though assert terminates the program, the C++ compiler cannot see that, and there is then undefined behaviour in that case
> because even though assert terminates the program, the C++ compiler cannot see that
I think it should be able to. I'm pretty sure assert is defined to call abort when triggered and abort is tagged with [[noreturn]], so the compiler knows control flow isn't coming back.
Shouldn't control flow diverge if the assert is triggered when NDEBUG is not defined? Pretty sure assert is defined to call abort when triggered and that is tagged [[noreturn]].
