diff --git a/ChangeLog b/ChangeLog
index 2d88f74d6b..6944ac57ec 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2016-06-09  Joseph Myers  <joseph@codesourcery.com>
 
+	[BZ #20233]
+	* sysdeps/ieee754/ldbl-128ibm/s_expm1l.c (__expm1l): Add NaN input
+	to itself.
+
 	[BZ #20232]
 	* sysdeps/ieee754/ldbl-128/s_expm1l.c (__expm1l): Add NaN input to
 	itself.
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_expm1l.c b/sysdeps/ieee754/ldbl-128ibm/s_expm1l.c
index 66f75e1c80..42d57c6eec 100644
--- a/sysdeps/ieee754/ldbl-128ibm/s_expm1l.c
+++ b/sysdeps/ieee754/ldbl-128ibm/s_expm1l.c
@@ -106,8 +106,8 @@ __expm1l (long double x)
       /* Infinity (which must be negative infinity). */
       if (((ix - 0x7ff00000) | lx) == 0)
 	return -1.0L;
-      /* NaN. No invalid exception. */
-      return x;
+      /* NaN.  Invalid exception if signaling.  */
+      return x + x;
     }
 
   /* expm1(+- 0) = +- 0.  */