[compiler-rt] r215295 - builtins: correct __umodsi3, __udivsi3 on ARM

[Renato Golin]

Done, thanks!

--renato

On 19 August 2014 23:55, Jim Grosbach <grosbach at apple.com> wrote:
> Thanks for the archaeology, folks. That answered my questions about how this came to be. LGTM for 3.5.
> -j
>> On Aug 19, 2014, at 3:40 PM, Renato Golin <renato.golin at linaro.org> wrote:
>>
>> So, we have look and we believe that this time, it's correct. Saleem's
>> patch does indeed fixes the two blatant bugs that we introduced by
>> copy&paste.
>>
>> Jim/Bill, we also believe this fix needs to be in 3.5, as things will
>> be completely broken if not. Can I merge it back?
>>
>> cheers,
>> --renato
>>
>> On 19 August 2014 23:04, Renato Golin <renato.golin at linaro.org> wrote:
>>> On 19 August 2014 22:55, Anton Korobeynikov <anton at korobeynikov.info> wrote:
>>>> Did some git / svn archaeology: support for cores with division
>>>> instructions was added in r182665 / a09d09d29e
>>>>
>>>> And the code there (see e.g.
>>>> http://llvm.org/klaus/compiler-rt/commit/a09d09d29e250e905bdfaf819979b9c3e9adc047/)
>>>> is precisely the same as in Saleem's latest commit.
>>>>
>>>> Looks like in r200001 umodsi3.S was completely replaced (!) by
>>>> udivmodsi4.S making it broken.
>>>>
>>>> CC'ing Joerg as he was the author of that commit.
>>>
>>> I think we need to look at this one carefully...
>>>
>>> Joerg may correct me, but I believe the intention was to implement a
>>> divmod, that happened to be in a badly named file (umod) and with a
>>> copy&paste mistake on the function name. So that one should actually
>>> be the divmod function, not the mod, and the latest Saleem's patch
>>> actually finished killing the original implementation at all, meaning
>>> that it's still divmod for armv4 but not for the rest, but being used
>>> as div/mod.
>>>
>>> I can't believe we used to pass all tests with compiler-rt on ARM
>>> about two months ago with that all messed up!
>>>
>>> This is the review in Phab:
>>>
>>> http://reviews.llvm.org/D2595
>>>
>>> cheers,
>>> --renato
>