[rurban]

No, it's super cheap. overflows happen <1%, so you mark it as UNLIKELY, and the branch prediction units just don't care about all those bignum branches.

If you know to use bigints or bignums, just type it and use their variants from the beginning.

Most better dynamic languages already use tagged ints, so they have only say ~30bits for an int and do a lot of those overflow checks and still beat the hell out of the poorly designed dynamic languages with full boxed ints or nums.