fmax/fmin sNaN compatibility question

[Joseph Myers]

On Mon, 9 Dec 2019, Ulrich Weigand wrote:

> So just to clarify: there was a sample implementation in C11, and now there
> is a (different) sample implementation in TS 18661-1 / C2x, but the expected
> behavior in FP_SNANS_ALWAYS_SIGNAL mode is neither of those, but rather the
> behavior described by maxNum from IEEE 754-2008.  Right?

Yes.

> Do you know why the sample implementation was even updated then?
> If FP_SNANS_ALWAYS_SIGNAL is false, shouldn't the C11 method then
> still be OK?

The canonicalize call is needed in general to avoid propagating 
noncanonical DFP encodings, though not relevant for binary FP.

-- 
Joseph S. Myers
joseph@codesourcery.com