3 files changed, 42 insertions, 12 deletions
diff --git a/sysdeps/ieee754/ldbl-128ibm-compat/Makefile b/sysdeps/ieee754/ldbl-128ibm-compat/Makefile
index 0ac52a53bc..7b42746c34 100644
--- a/sysdeps/ieee754/ldbl-128ibm-compat/Makefile
+++ b/sysdeps/ieee754/ldbl-128ibm-compat/Makefile
@@ -249,13 +249,6 @@ ldbl-extra-routines += err \
 CFLAGS-ieee128-qefgcvt.c += -mabi=ieeelongdouble -Wno-psabi -mno-gnu-attribute
 CFLAGS-ieee128-qefgcvt_r.c += -mabi=ieeelongdouble -Wno-psabi -mno-gnu-attribute
 
-# Remove -mlong-double-128 because it does not work correctly with
-# -mabi=ibmlongdoule in some GCC versions, e.g. GCC 7.
-$(foreach o,$(all-object-suffixes),$(objpfx)ieee128-qefgcvt$(o)): \
-  sysdep-CFLAGS := $(filter-out -mlong-double-128, $(sysdep-CFLAGS))
-$(foreach o,$(all-object-suffixes),$(objpfx)ieee128-qefgcvt_r$(o)): \
-  sysdep-CFLAGS := $(filter-out -mlong-double-128, $(sysdep-CFLAGS))
-
 tests-internal += tst-ibm128-warn tst-ieee128-warn
 tests-internal += tst-ibm128-error tst-ieee128-error
 tests-internal += tst-ibm128-efgcvt tst-ieee128-efgcvt
@@ -348,11 +341,6 @@ ldbl-ibm128-files := $(objpfx)test-%-ibm128^ \
 		     $(foreach r,$(ldbl-extra-routines),$(objpfx)$(r)-internal^)
 obj-suf-foreach = $(foreach suf,$(all-object-suffixes),$(subst ^,$(suf),$(1)))
 
-# Remove -mlong-double-128 because it does not work correctly with
-# -mabi=ibmlongdoule in some GCC versions, e.g. GCC 7.
-$(call obj-suf-foreach,$(ldbl-ibm128-files)): \
-  sysdep-CFLAGS := $(filter-out -mlong-double-128, $(sysdep-CFLAGS))
-
 # Explicitly add -mabi=ibm-long-double to required files.
 $(call obj-suf-foreach,$(ldbl-ibm128-files)): \
   sysdep-CFLAGS += -mabi=ibmlongdouble
diff --git a/sysdeps/powerpc/powerpc64/le/configure b/sysdeps/powerpc/powerpc64/le/configure
index bd7b8e77d0..98a4889945 100644
--- a/sysdeps/powerpc/powerpc64/le/configure
+++ b/sysdeps/powerpc/powerpc64/le/configure
@@ -90,6 +90,33 @@ if test "$libc_cv_compiler_powerpc64le_ice" != "yes"; then :
   critic_missing="$critic_missing __builtin_signbit is broken.  GCC 7.4 or newer is required to resolve (PR83862)."
 fi
 
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if $CC compiles with -mabi=ieeelongdouble and -mlong-double-128" >&5
+$as_echo_n "checking if $CC compiles with -mabi=ieeelongdouble and -mlong-double-128... " >&6; }
+if ${libc_cv_compiler_powerpc64le_ldbl128_mabi+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  save_CFLAGS="$CFLAGS"
+CFLAGS="$CFLAGS -mabi=ieeelongdouble -mlong-double-128"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+long double x;
+
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  libc_cv_compiler_powerpc64le_ldbl128_mabi=yes
+else
+  libc_cv_compiler_powerpc64le_ldbl128_mabi=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+CFLAGS="$save_CFLAGS"
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_compiler_powerpc64le_ldbl128_mabi" >&5
+$as_echo "$libc_cv_compiler_powerpc64le_ldbl128_mabi" >&6; }
+if test "$libc_cv_compiler_powerpc64le_ldbl128_mabi" == "no"; then :
+  critic_missing="$critic_missing The compiler must support -mabi=ieeelongdouble and -mlongdouble simultaneously."
+fi
+
 for ac_prog in $OBJCOPY
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
diff --git a/sysdeps/powerpc/powerpc64/le/configure.ac b/sysdeps/powerpc/powerpc64/le/configure.ac
index 405933e710..769c06709e 100644
--- a/sysdeps/powerpc/powerpc64/le/configure.ac
+++ b/sysdeps/powerpc/powerpc64/le/configure.ac
@@ -51,6 +51,21 @@ CFLAGS="$save_CFLAGS"])
 AS_IF([test "$libc_cv_compiler_powerpc64le_ice" != "yes"],
       [critic_missing="$critic_missing __builtin_signbit is broken.  GCC 7.4 or newer is required to resolve (PR83862)."])
 
+dnl Some old compiler versions give out error messages when combining
+dnl -mabi=% and -mlong-double-128.  i.e GCC 7.5.0 (PR94200)
+AC_CACHE_CHECK([if $CC compiles with -mabi=ieeelongdouble and -mlong-double-128],
+	       libc_cv_compiler_powerpc64le_ldbl128_mabi, [dnl
+save_CFLAGS="$CFLAGS"
+CFLAGS="$CFLAGS -mabi=ieeelongdouble -mlong-double-128"
+AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
+long double x;
+]])],
+		  [libc_cv_compiler_powerpc64le_ldbl128_mabi=yes],
+		  [libc_cv_compiler_powerpc64le_ldbl128_mabi=no])
+CFLAGS="$save_CFLAGS"])
+AS_IF([test "$libc_cv_compiler_powerpc64le_ldbl128_mabi" == "no"],
+      [critic_missing="$critic_missing The compiler must support -mabi=ieeelongdouble and -mlongdouble simultaneously."])
+
 dnl objcopy (binutils) 2.26 or newer required to support the --update-section
 dnl feature for fixing up .gnu.attribute section with IEEE ldbl.
 AC_CHECK_PROG_VER(OBJCOPY, $OBJCOPY, --version,