Re: [PATCH 2/3] PowerPC: remove wrong nearbyintl implementation for, PowerPC64

["Joseph S. Myers" <joseph at codesourcery dot com>]

On Fri, 14 Mar 2014, Joseph S. Myers wrote:

> On Fri, 14 Mar 2014, Adhemerval Zanella wrote:
> 
> > +#ifdef TEST_LDOUBLE
> > +    /* Check cases where first double is a exact integer higher than 2^52 and
> > +       the precision is determined by second long double for IBM long double.  */
> > +    TEST_f_f (nearbyint,  34503599627370498.515625L, 34503599627370499.0L),
> > +    TEST_f_f (nearbyint,  1192568192774434123539907640624.484375L, 1192568192774434123539907640624.0L),
> > +    TEST_f_f (nearbyint, -34503599627370498.515625L, -34503599627370499.0L),
> > +    TEST_f_f (nearbyint, -1192568192774434123539907640624.484375L, -1192568192774434123539907640624.0L),
> > +#endif
> 
> What are the precision requirements on long double for these inputs to be 
> representable?  If any require more than 64-bit mantissa, they should be 
> conditional appropriately on LDBL_MANT_DIG (which may be 64, 106 or 113).

Note that this applies to the other functions as well.  In some cases a 
test may accidentally pass without such a conditional, if both the input 
and expected output round-to-nearest to the same long double value.  But 
that won't help for these tests when I make rint and nearbyint use the 
same tests (once 
<https://sourceware.org/ml/libc-alpha/2014-03/msg00214.html> is reviewed), 
with the tests for rint systematically expecting "inexact".  (These 
nearbyint tests in your patch are also missing NO_INEXACT_EXCEPTION, which 
should be specified as that's the whole difference between rint and 
nearbyint.)

-- 
Joseph S. Myers
joseph@codesourcery.com