[Bug modula2/111956] Many powerpc platforms do _not_ have support for IEEE754 long double

["tschwinge at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111956

--- Comment #10 from Thomas Schwinge <tschwinge at gcc dot gnu.org> ---
In addition to what Maciej said (..., and similarly, I don't have any proper
knowledge about PowerPC details):

(In reply to Gaius Mulley from comment #6)
> Created attachment 56522 [details]
> Proposed fix v5

Thanks for looking into this!

> Here is the latest patch which [...] 96
> failures on gcc135.  [...]

With no special 'configure' flags, I'm seeing (presumably) those, too.

I noticed in 'build-gcc/gcc/m2/config-make' (generated from
'gcc/m2/config-make.in'):

    # Does the target have -mabi=ieeelongdouble support in libm?  (yes/no).
    HAVE_TARGET_LONG_DOUBLE_IEEE = @have_target_long_double_ieee@

..., so missing 'AC_SUBST' or similar -- but is that actually unused?

I further noticed the following delta when regenerating 'libgm2/configure':

     case "$target" in
        powerpc*-*-linux*)
    -     LONG_DOUBLE_COMPAT_FLAGS="$LONG_DOUBLE_COMPAT_FLAGS
-mno-gnu-attribute"
          # Check for IEEE128 support in libm:


(In reply to Gaius Mulley from comment #8)
> Here is the same patch as v5 but generated using git diff -w.

Please don't include unrelated changes (here: whitespace cleanup); handle that
separately (if you must).  ;-)