Comment by MichaelBurge
3 years ago
C++ bans undefined behavior in constexpr, so you can force GCC to prove that code has no undefined behavior by sprinkling it in declarations where applicable:
https://shafik.github.io/c++/undefined%20behavior/2019/05/11...
Constant-evaluated expressions with undefined behavior are ill-formed but constexpr annotated functions which may in some invocations result in undefined behavior are not.