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Re: [PATCH 3/3] powerpc64le: Disable compiler support for float128 when reusing ldbl-128
On Thu, 7 Sep 2017, Gabriel F. T. Gomes wrote:
> Some files under sysdeps/ieee754/ldbl-128ibm are able to reuse the
> implementation in sysdeps/ieee754/ldbl-128 by defining _Float128 to long
> double. This relies on compiler support for _Float128 being disabled.
>
> On powerpc, such support is currently disabled by default, however, it
> will get enabled by default [1], requiring that this Makefile actively
> disable compiler support for float128 for the required files.
I think it would be better to stop #include of ldbl-128 files from
ldbl-128ibm. That is, copy the relevant source files (in the case of
e_expl.c that's actually t_expl.h) to ldbl-128ibm, with _Float128
converted to long double and L() also expanded back to adding L suffixes.
And, in the e_lgammal_r.c case, then eliminate the present LDBL_MANT_DIG
conditionals from both copies.
Long term I'd like the ldbl-128 files to e.g. use f128 constant suffixes
directly (once we can assume GCC >= 7 to build glibc), with such changes
cleaning up the code but being incompatible with its use also for
ldbl-128ibm.
--
Joseph S. Myers
joseph@codesourcery.com