It is. Or if it is unfeasible to implement then it can be considered to be a defect in the standard. Consider that something like (++*ptr1) + (++*ptr2) may or

It is. Or if it is unfeasible to implement then it can be considered to be a defect in the standard. Consider that something like (++*ptr1) + (++*ptr2) may or may not be UB, depending where the pointer points to. The required additional bookkeeping might make compile time evaluation unpractically slow. Alternatively the sequencing could be always defined between any two subexpressions within constexpr context.