Pretty sure the std::abort() can't be optimized away if sz is mutable since it's legal for some_opaque_func() to cast away szRef's const and modify sz via that.

Pretty sure the std::abort() can't be optimized away if sz is mutable since it's legal for some_opaque_func() to cast away szRef's const and modify sz via that. sz itself needs to be const for the if statement to be removable as dead code. https://cpp.godbolt.org/z/Pa3bMh9Ee https://cpp.godbolt.org/z/Pa3bMh9Ee shows that both GCC and Clang keep the abort when sz is not const. Add const and the abort goes away.