diff --git a/math/Makefile b/math/Makefile
index 1d203e7ad5..84a8b94c74 100644
--- a/math/Makefile
+++ b/math/Makefile
@@ -145,10 +145,15 @@ type-float128-yes := float128
 # _Float64x may be supported, only as an alias type.
 type-float64x-yes := float64x
 
+# IBM long double support in additional to IEEE 128 long double support
+type-ibm128-suffix := l
+type-ibm128-yes := ibm128
+
 types = $(types-basic) $(type-float128-$(float128-fcts))
 test-types = $(test-types-basic) $(type-float128-$(float128-fcts)) \
 	     float32 float64 $(type-float128-$(float128-alias-fcts)) \
-	     float32x $(type-float64x-$(float64x-alias-fcts))
+	     float32x $(type-float64x-$(float64x-alias-fcts)) \
+	     $(type-ibm128-$(ibm128-fcts))
 
 # Pairs of types for which narrowing functions should be tested (this
 # variable has more entries than libm-narrow-types because it includes
diff --git a/math/test-float128.h b/math/test-float128.h
index 8f9eec14aa..07945a090b 100644
--- a/math/test-float128.h
+++ b/math/test-float128.h
@@ -28,7 +28,7 @@
 #define CFLOAT __CFLOAT128
 #define BUILD_COMPLEX(real, imag) (CMPLXF128 ((real), (imag)))
 #define PREFIX FLT128
-#if FLT128_MANT_DIG == LDBL_MANT_DIG
+#if __LONG_DOUBLE_USES_FLOAT128 == 0 && FLT128_MANT_DIG == LDBL_MANT_DIG
 # define TYPE_STR "ldouble"
 # define ULP_IDX ULP_LDBL
 # define ULP_I_IDX ULP_I_LDBL
diff --git a/math/test-float64x.h b/math/test-float64x.h
index 9543238209..f8e7ef2f66 100644
--- a/math/test-float64x.h
+++ b/math/test-float64x.h
@@ -28,7 +28,7 @@
 #define CFLOAT __CFLOAT64X
 #define BUILD_COMPLEX(real, imag) (CMPLXF64X ((real), (imag)))
 #define PREFIX FLT64X
-#if FLT64X_MANT_DIG == LDBL_MANT_DIG
+#if __LONG_DOUBLE_USES_FLOAT128 == 0 && FLT64X_MANT_DIG == LDBL_MANT_DIG
 # define TYPE_STR "ldouble"
 # define ULP_IDX ULP_LDBL
 # define ULP_I_IDX ULP_I_LDBL
diff --git a/math/test-ibm128.h b/math/test-ibm128.h
new file mode 100644
index 0000000000..cd67fd1493
--- /dev/null
+++ b/math/test-ibm128.h
@@ -0,0 +1,19 @@
+/* Common definitions for libm tests for ibm long double.
+   Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include "test-ldouble.h"
diff --git a/math/test-ldouble.h b/math/test-ldouble.h
index 17c526bd71..c0a7a94cc1 100644
--- a/math/test-ldouble.h
+++ b/math/test-ldouble.h
@@ -27,6 +27,12 @@
 # define TYPE_STR "double"
 # define ULP_IDX ULP_DBL
 # define ULP_I_IDX ULP_I_DBL
+#elif __LONG_DOUBLE_USES_FLOAT128 == 1
+# define TYPE_STR "float128"
+# define ULP_IDX ULP_FLT128
+# define ULP_I_IDX ULP_I_FLT128
+/* _Float128 unconditionally redirects to lgamma. Ensure the ULPs do too. */
+# define gamma lgamma
 #else
 # define TYPE_STR "ldouble"
 # define ULP_IDX ULP_LDBL
diff --git a/sysdeps/ieee754/ldbl-128ibm-compat/Makeconfig b/sysdeps/ieee754/ldbl-128ibm-compat/Makeconfig
new file mode 100644
index 0000000000..997f632319
--- /dev/null
+++ b/sysdeps/ieee754/ldbl-128ibm-compat/Makeconfig
@@ -0,0 +1,3 @@
+# Include this earlier so it can be used earlier in Makefiles,
+# and sysdep/ makefiles.
+ibm128-fcts = yes
diff --git a/sysdeps/powerpc/powerpc64/le/Makefile b/sysdeps/powerpc/powerpc64/le/Makefile
index 0ce3868c3c..1594f6b179 100644
--- a/sysdeps/powerpc/powerpc64/le/Makefile
+++ b/sysdeps/powerpc/powerpc64/le/Makefile
@@ -6,6 +6,13 @@
 # linked executables, forcing to link the loader after libgcc link.
 f128-loader-link = -Wl,--as-needed $(elf-objpfx)ld.so -Wl,--no-as-needed
 
+# Bootstrapping code for enabling IEEE 128.  This can be removed and
+# any indirections simplified once IEEE 128 long double is enabled.
+type-ldouble-CFLAGS =
+ifeq ($(ibm128-fcts),yes)
+type-ldouble-CFLAGS += -mabi=ibmlongdouble
+endif
+
 ifeq ($(subdir),math)
 # sqrtf128 requires emulation before POWER9.
 CPPFLAGS += -I../soft-fp
@@ -28,13 +35,34 @@ CFLAGS-test-math-iscanonical.cc += -mfloat128
 CFLAGS-test-math-iseqsig.cc += -mfloat128
 CFLAGS-test-math-issignaling.cc += -mfloat128
 CFLAGS-test-math-iszero.cc += -mfloat128
-$(foreach test, \
-	  test-float128% test-ifloat128% test-float64x% test-ifloat64x% \
-	  $(foreach pair,$(f128-pairs),test-$(pair)%) \
-	  test-math-iscanonical test-math-iseqsig test-math-issignaling \
-	  test-math-iszero, \
-	  $(objpfx)$(test)): \
+$(foreach test,\
+	  basic-test \
+	  bug-nextafter \
+	  bug-nexttoward \
+	  test-fenv-clear \
+	  test-iszero-excess-precision \
+	  test-math-iscanonical \
+	  test-math-iseqsig \
+	  test-math-issignaling \
+	  test-math-iszero \
+	  test-misc \
+	  test-nan-overflow \
+	  test-nan-payload \
+	  test-snan \
+	  test-tgmath \
+	  test-tgmath2 \
+	  tst-CMPLX2 \
+	  test-%-ldbl-128ibm \
+	  test-ldouble% test-ildouble% \
+	  test-float128% test-ifloat128% \
+	  test-float64x% test-ifloat64x% \
+	  ,$(objpfx)$(test)): \
   gnulib-tests += $(f128-loader-link)
+
+$(foreach suf,$(all-object-suffixes),\
+         $(objpfx)libm-test-%ibm128$(suf) \
+         $(objpfx)test-iibm128%$(suf) $(objpfx)test-ibm128%$(suf)): \
+  CFLAGS += $(type-ldouble-CFLAGS)
 endif
 
 # Append flags to string <-> _Float128 routines.
@@ -82,3 +110,13 @@ CFLAGS-printf_fp.c = -mfloat128
 CFLAGS-printf_fphex.c = -mfloat128
 CFLAGS-printf_size.c = -mfloat128
 endif
+
+$(foreach suf,$(all-object-suffixes),nldbl-%$(suf)): \
+  CFLAGS += $(type-ldouble-CFLAGS)
+
+sysdep-CFLAGS += -mabi=ieeelongdouble -Wno-psabi
+$(foreach suf,$(all-object-suffixes),\
+         $(objpfx)libm-test-%ibm128$(suf) \
+         $(objpfx)test-iibm128%$(suf) $(objpfx)test-ibm128%$(suf)): \
+  sysdep-CFLAGS := $(filter-out -mabi=ieeelongdouble \
+    -Wno-psabi, $(sysdep-CFLAGS))
