Re: float128 in libstdc++

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Sat, Jun 24, 2017 at 11:27:47AM +0200, Martin Husemann wrote:
> On Fri, Jun 23, 2017 at 10:27:40PM +0200, Kamil Rytarowski wrote:
> >  3. Disable float128 in libstdc++ for everybody.
> 
> You are missing the obvious one:
> 
>  4. Disable float128 for all architectures that have no hardware support
>     for it (this would basically be all 32bit ones plus a few 64bit,
>     including x68_64 IIUC) and where the ABI does not require this
>     format for long double (for example sparc64).
> 
> Providing this format for anything else just makes no sense to me.
> The availability should not depend on the compiler used.

I am similarly skeptical about whether we should expose a floating
point format not supported by the hardware and which is likely to
cause ill-written or ill-configured applications to run slowly with
software floating point and precision they don't actually need,
instead of quickly with hardware floating point and enough precision
already.

Thor