Hi Andreas,
On Tue, Feb 08, 2022 at 06:36:57PM +0100, Andreas Schwab wrote:
> On Feb 08 2022, Peter Bergner wrote:
> > Can you please clarify one thing for me. Do you think it's possible
> > that we can come up with some type of configure patch that automatically
> > sets the long double default given something on the system we can test
> > for or do you think that's impossible and we'll just have to live with
> > explicitly using a configure option to set the default?
>
> It should be handled the same as the double->long double switch.
So how was that done? It's not something I can find online ("long
double conversion" does not find it, heh). Was it just a flag day where
the default was changed?
IMO it is a bad idea to change configuration without the user asking for
it (and even doing that silently). It is hard enough and painful enough
to do this conversion in the first place, we do not need twice as many
user configurations (that are not even shown by gcc -v, etc.)
Testing is hard. Testing twice as many configurations is twice as hard.
The only outcome that can be reasonably expected is that at least half
of the new configurations will not be tested at all. And that is very
expensive, because there will be a lot of wasted work and frustration
for whoever gets to handle bug reports, and ditto for whoever gets to
deal with a bug that was not handled (aka, a worse user experience).
The apparent goal here is to give users compilers that default to IEEE
QP long double earlier. That is a fine goal, but it should be achieved
bu actually changing the default earlier, not by leaving behind a large
fraction of users!
Segher
