Fix ctan, ctanh of subnormals in round-upwards mode (bug 14328)

[Joseph S. Myers]

On Mon, 9 Jul 2012, Adhemerval Zanella wrote:

> On 07/08/2012 05:17 PM, Joseph S. Myers wrote:
> 
> > Actually I noted that sqrt (epsilon) is really what's relevant here (just 
> > not convenient to write generically), so you might as well use DBL_EPSILON 
> > or 0xp1-53L or similar.
> >
> > I'd say such constants are better written as hex floats, 0x1p-106L in this 
> > case (any floating-point constant where you intend an exact bit pattern 
> > for a particular floating-point format is better written as a hex float 
> > unless there is a short exact decimal expansion for it).
> >
> Thanks for the review, I'll rewrite the epsilon constant as hexa format, 
> but I think it is best to keep the ldbl-128ibm implementation close to 
> the one you already committed, instead of fix the spurious overflow 
> using another logic. Don't you think?

Yes, keeping the implementations similar makes sense in the absence of any 
attempt to do something special for the discontiguous mantissas of 
ldbl-128ibm.

-- 
Joseph S. Myers
joseph@codesourcery.com