diff --git a/math/s_significand_template.c b/math/s_significand_template.c
new file mode 100644
index 0000000000..c95017e683
--- /dev/null
+++ b/math/s_significand_template.c
@@ -0,0 +1,33 @@
+/* Return the mantissa of a floating-point number.
+ 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
+ . */
+
+/*
+ * significand(x) computes just
+ * scalb(x, (long double) - ilogb(x)),
+ * for exercising the fraction-part(F) IEEE 754-1985 test vector.
+ */
+
+#include
+#include
+
+FLOAT
+M_DECL_FUNC (__significand) (FLOAT x)
+{
+ return M_SUF (__ieee754_scalb) (x,(FLOAT) - M_SUF (__ilogb) (x));
+}
+declare_mgen_alias (__significand, significand)
diff --git a/sysdeps/ieee754/ldbl-128ibm-compat/Versions b/sysdeps/ieee754/ldbl-128ibm-compat/Versions
index 8133d874df..06c19569c5 100644
--- a/sysdeps/ieee754/ldbl-128ibm-compat/Versions
+++ b/sysdeps/ieee754/ldbl-128ibm-compat/Versions
@@ -110,6 +110,7 @@ libm {
__scalbnieee128;
__setpayloadieee128;
__setpayloadsigieee128;
+ __significandieee128;
__sincosieee128;
__sinhieee128;
__sinieee128;
diff --git a/sysdeps/ieee754/ldbl-128ibm-compat/s_significandf128.c b/sysdeps/ieee754/ldbl-128ibm-compat/s_significandf128.c
new file mode 100644
index 0000000000..4ae0fde6a5
--- /dev/null
+++ b/sysdeps/ieee754/ldbl-128ibm-compat/s_significandf128.c
@@ -0,0 +1,25 @@
+/* Get mantissa of 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
+ . */
+
+#include
+#include
+
+#define __significandf128 __significandieee128
+#undef declare_mgen_alias
+#define declare_mgen_alias(...)
+#include