... except that even my idea fails to help with software math. If the programmer writes `uint128 a, b; ... a /= b` under -Obranchless, does that mean they don't

... except that even my idea fails to help with software math. If the programmer writes `uint128 a, b; ... a /= b` under -Obranchless, does that mean they don't want us calling a C++-runtime software division routine (__udiv3 or however it's spelled) that might contain branches? And if so, then what on earth do we do instead? — well, just give an error at compile time, I guess.