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

[kewuzhang]

That is very clear!

best

kevin

On Feb 17, 2015, at 2:13 PM, Tim Northover <t.p.northover at gmail.com> wrote:

> 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.