> I wonder if we could design an integer type with 63 bits of value, plus one bit of "overflow/underflow poison", such that any operation that would under/overf

> I wonder if we could design an integer type with 63 bits of value, plus one bit of "overflow/underflow poison", such that any operation that would under/overflow would saturate that bit to one, but otherwise still perform the operation on the value part. That would allow to coalesce multiple checks while keeping safety even in the presence of multiple faulty operations. I wonder how it could be implemented efficiently though There is something like that already for floating point. Whenever an overflow or underflow happens, it sets a sticky bit in a separate flags register. You can clear these flags, do a sequence of operations, and at the end, see if any of these flags are set. See https://man7.org/linux/man-pages/man3/fenv.3.html https://man7.org/linux/man-pages/man3/fenv.3.html for the standard C API for it.