Re: k_sinl bug fix for ldbl-128 and ldbl-128ibm

[David Miller <davem at davemloft dot net>]

From: "Joseph S. Myers" <joseph@codesourcery.com>
Date: Wed, 21 Mar 2012 21:31:36 +0000 (UTC)

> On Fri, 16 Mar 2012, Joseph S. Myers wrote:
> 
>> On Fri, 16 Mar 2012, Joseph S. Myers wrote:
>> 
>> > On Thu, 15 Mar 2012, David Miller wrote:
>> > 
>> > > This gives new ULPs on sparc, this is test-ldouble.out:
>> > 
>> > Hopefully it also reduces some ULPs (which is less visible) so being on 
>> > average better (as was the case when making this fix for ldbl-96).
>> > 
>> > I had the idea last night that this issue only affected k_sinl, but on 
>> > looking at it again I think k_cosl is affected as well (and k_sincosl, 
>> > which I didn't pay much attention to because I'm keeping the existing 
>> > ldbl-96 s_sincosl for now which doesn't use k_sincosl).  So I'll post 
>> > revised versions of both patches that fix those other functions as well.
>> 
>> Like so.  The corresponding cosl fix for ldbl-96 reduces the number of 
>> ulps changes for test-ldouble on x86 from 20 to 16 (fixing sinl having 
>> reduced the number from 30 to 20).  (These are figures in the presence of 
>> the testsuite changes from the ldbl-96 patch - so include both ULPs for 
>> tests that patch newly enables as well as ULPs for tests that were already 
>> being run for long double.)
> 
> I have now tested this patch 
> <http://sourceware.org/ml/libc-alpha/2012-03/msg00513.html> for powerpc, 
> with the existing ulps removed so it's tested fairly rather than on a 
> basis where whatever random errors the existing code has are expected and 
> whatever random errors the new code has aren't.  With the patch applied, 
> there were 272 errors in test-ldouble.out compared to 276 without (and two 
> values for max errors of particular functions went down).
> 
> On that basis I think we have further evidence from testing that this is a 
> sound change - is the patch OK?

I'm personally fine with it, and I'll scrutinize the resulting sparc ULPs
similarly to how you did for the powerpc ones once you commit this.