diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index d180e38b59..f922735bb1 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2015-04-27  Andreas Arnez  <arnez@linux.vnet.ibm.com>
+
+	* s390-linux-tdep.c (is_power_of_two): Add comment.  Return
+	  false if the argument is zero.
+
 2015-04-27  Pierre-Marie de Rodat  <derodat@adacore.com>
 
 	* ada-lang.c (template_to_static_fixed_type): Return input type
diff --git a/gdb/s390-linux-tdep.c b/gdb/s390-linux-tdep.c
index b83a264ee8..44feee7bbe 100644
--- a/gdb/s390-linux-tdep.c
+++ b/gdb/s390-linux-tdep.c
@@ -2484,11 +2484,12 @@ is_float_like (struct type *type)
 	  || is_float_singleton (type));
 }
 
+/* Determine whether N is a power of two.  */
 
 static int
 is_power_of_two (unsigned int n)
 {
-  return ((n & (n - 1)) == 0);
+  return n && ((n & (n - 1)) == 0);
 }
 
 /* Return non-zero if TYPE should be passed as a pointer to a copy,