Re: [PATCH] fortran, libgfortran, v2: Avoid using libquadmath for glibc 2.26+

[Mikael Morin <morin-mikael@orange.fr>]

Le 27/06/2022 à 09:54, Jakub Jelinek a écrit :
> Still, using __float128 when the APIs are declared for __float128 and
> _Float128 when the APIs are declared for _Float128 can be better for
> consistency.
> 
I agree with that.
I was implicitly suggesting to change the libquadmath API to use the 
standard syntax and types, with the assumption that it’s an internal 
thing used only by fortran (on the frontend side and on the library 
side). After documenting myself further, it seems that’s a wrong 
assumption.


> If HAVE_FLOAT128 and GFC_REAL_16_IS_FLOAT128 stand for
> _Float128 and libquadmath or *f128 APIs, we'd need some macro
> to tell which APIs to use, say
> USE_LIBQUADMATH and USE_IEC_60559.

That would be my preference, even if we keep both __float128 and 
_Float128, as it avoids exposing the detail of the provider of the math 
functions in many places it’s not needed.
Half of the changes from your patch have pattern blah__float128 || 
blah_Float128 or the negation of that, and wouldn’t be needed if the 
*FLOAT128 conditions spanned both __float128 and _Float128 (or 
libquadmath and libc).