We already see a bug caused by signed integer overflow UB. If it does not hurt performance, we should enable this option to avoid such an UB. Personally, I think this UB is one of the most common UBs resulting in an actual bug. An attempt making this behavior by default in the spec exists[1]. While the main focus of that proposal is accepted, "making signed overflow well-defined" is rejected. So we should enable -fwrapv / d2UndefIntOverflow manually in the WebKit side. > Status-quo If a signed operation would naturally produce a value that is not within the range of the result type, the behavior is undefined. > The author had hoped to make this well-defined as wrapping (the operations produce the same value bits as for the corresponding unsigned type), but WG21 had strong resistance against this. [1]: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p0907r2.html
Maybe, this would be my weekend task just for fun.