[gsg]

That still exists though? add rax, rbx/jo overflow_error is how you do overflow checking on x86-64.

[chrisseaton]

That doesn’t work with a lot of arithmetic, so you have to use slower arithmetic in order to use it.

[gsg]

Sure, but that didn't change much between x86 and x86-64. Perhaps it got a little worse because the SIMD instructions aren't overflow check friendly.