[LLVMdev] [PATH] Add sub.ovf/mul.ovf intrinsics

Zoltan Varga vargaz at gmail.com
Tue Dec 9 13:12:34 PST 2008


Hi,

  Attached is the final version of the patch, adding the requested
FIXME. If this is ok, can
somebody check it in ?

                                thanks

                                      Zoltan

On Tue, Dec 9, 2008 at 9:58 PM, Bill Wendling <isanbard at gmail.com> wrote:
> On Tue, Dec 9, 2008 at 6:11 AM, Zoltan Varga <vargaz at gmail.com> wrote:
>> Hi,
>>
>>  Here is the next iteration of the patch. The only comment not
>> addressed is this one:
>>
> Thanks! It's looking good.
>
>>> It would be better to implement a target-independent check for
>>> overflow for the "Legal" case (like how SADDO does). Hacker's > Delight
>>> has some hints on how to do this. It's not easy for the signed case,
>>> but is do-able.
>>
>> It can be lowered to a division + a branch, so it would be
>> inefficient, plus it would
>> be a lot of work to implement it correctly (for me at least).
>>
> Okay. It would be tricky. Please put a "FIXME" in there indicating
> that it would be nice to have at some point. It's okay to submit this.
>
> -bw
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