diff --git a/libs/libm/libm/lib_truncl.c b/libs/libm/libm/lib_truncl.c
index 8dc245e3eea37..2c5511b4fbc12 100644
--- a/libs/libm/libm/lib_truncl.c
+++ b/libs/libm/libm/lib_truncl.c
@@ -44,9 +44,20 @@
  ****************************************************************************/
 
 #ifdef CONFIG_HAVE_LONG_DOUBLE
+#if LDBL_MANT_DIG == DBL_MANT_DIG
+
+/* Cover case when double is the same as long double (64 bit ieee754). */
+
+long double truncl(long double x)
+{
+  return trunc(x);
+}
+
+#else
+
 static const long double toint = 1 / LDBL_EPSILON;
 
-/* FIXME This will only work if long double is 64 bit and little endian */
+/* FIXME This will only work if long double is 80 bit and little endian */
 
 union ldshape
 {
@@ -101,3 +112,4 @@ long double truncl(long double x)
   return s ? -x : x;
 }
 #endif
+#endif