[PATCH v2] powerpc: Update ULPs and output for j0 with ibm128

[Tulio Magno Quites Machado Filho]

Joseph Myers <joseph@codesourcery.com> writes:

> The first version is appropriate.  The bigger limits for ibm128 are 
> deliberate.  An architecture-specific ulps update should not be rejected 
> just because it increases ulps within the bounds accepted for that format 
> (and you shouldn't be able to get an update that increases them outside 
> those bounds unless you edit the ulps file manually, and if you do edit it 
> manually then the ulps it lists outside those bounds will be ignored 
> anyway).
>
> The most likely reason for rejecting an ulps update is that new ulps are 
> greater than for other architectures using the same code in glibc for the 
> same functions for the same format, suggesting that the update is actually 
> covering up a bug somewhere else.  This doesn't apply in this case.
>
> (If an ulps increase results from a change to the implementation of a libm 
> functions that makes it less accurate in some cases, we need to consider 
> if we want that change, but that's deciding whether we want the libm 
> change, not deciding whether we want the ulps updates consequent on it.)

Ack.
Thanks for clarifying!

Carlos O'Donell via Libc-alpha <libc-alpha@sourceware.org> writes:

> It was later shown to me that >9 ULPs was acceptable for ibm128, my apologies
> for not being clearer that I was withdrawing my objection.

Actually, I should be the one apologizing.

> Patsy Griffin from my team also suggested this on September 2nd, she
> is seeing these failures in our own testing. It would be good to have
> them resolved.

Especially after Patsy's message.

> Before this patch, the following tests were failing:
>
> ppc and ppc64:
>     FAIL: math/test-ldouble-j0
>
> ppc64le:
>     FAIL: math/test-float128-j0
>     FAIL: math/test-float64x-j0
>     FAIL: math/test-ibm128-j0
>     FAIL: math/test-ldouble-j0

Tested and pushed as c71d13a0984f6.

Thank you all!!

-- 
Tulio Magno