Fix powerpc round, roundf spurious "inexact" (bug 19238) [committed]

[Adhemerval Zanella]

On 17-12-2015 14:55, Joseph Myers wrote:
> On Thu, 17 Dec 2015, Steven Munroe wrote:
> 
>>> This issue and fix do not apply to builds using power5+ versions of
>>> round and roundf, which use the frin instruction and avoid "inexact"
>>> exceptions that way.
>>>
>> Joseph this gets confusing when we introduce the multiarch IFUNC
>> support. In a modern system (POWER6/7/8 the code below should never be
>> used. The code from:
> 
> Yes, I already said this code isn't used when the power5+ versions are 
> used.  My 64-bit powerpc testing is on a POWER4 system and my 32-bit 
> testing is on a 476 system; although I now have access to a little-endian 
> POWER8 system I haven't tried glibc testing there.
> 

You can also trigger this kind of failures with --disable-multi-arch --with-cpu=power4
(for instance) on newer chips.