[LLVMdev] why llvm does not have uadd, iadd node

[Tim Northover]

On 17 February 2015 at 11:08, kewuzhang <kewu.zhang at amd.com> wrote:
> So if the overflow happens for either one of the case, the return value will be implementation dependent?

If the instructions have "nuw" or "nsw" flags, the results are
undefined in the respective case.

Otherwise they're defined to follow C's unsigned rules (i.e. they
return the full precision unsigned sum/difference reduced mod 2^n).

Cheers.

Tim.