| Message ID | 20170907104352.7748-4-gabriel@inconstante.eti.br |
|---|---|
| State | New |
| Headers | show |
| Series | Fixes for -mfloat128 being enabled by default on gcc for power | expand |
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.
diff --git a/sysdeps/powerpc/powerpc64le/Makefile b/sysdeps/powerpc/powerpc64le/Makefile index 3fd9d9a715..a1d37135e5 100644 --- a/sysdeps/powerpc/powerpc64le/Makefile +++ b/sysdeps/powerpc/powerpc64le/Makefile @@ -20,6 +20,19 @@ CFLAGS-test-math-issignaling.cc += -mfloat128 CFLAGS-test-math-iszero.cc += -mfloat128 $(objpfx)test-float128% $(objpfx)test-ifloat128% $(objpfx)test-math-iszero: \ gnulib-tests += $(f128-loader-link) + +# 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 used to be disabled by default, +# however, it will get enabled by default [1], requiring that this +# Makefile actively disable it for the following files. +# [1] https://gcc.gnu.org/ml/gcc-patches/2017-08/msg01028.html +CFLAGS-e_expl.c += -mno-float128 +CFLAGS-e_j0l.c += -mno-float128 +CFLAGS-e_j1l.c += -mno-float128 +CFLAGS-e_lgammal_r.c += -mno-float128 +CFLAGS-s_cbrtl.c += -mno-float128 endif # Append flags to string <-> _Float128 routines.