diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d4779690e9e..702be36a796 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,7 @@
+2016-10-20  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>
+
+	* config/s390/s390.md ("prefetch"): Add fallthrough comment.
+
 2016-10-20  Prathamesh Kulkarni  <prathamesh.kulkarni@linaro.org>
 
 	PR tree-optimization/53979
diff --git a/gcc/config/s390/s390.md b/gcc/config/s390/s390.md
index 9de442f085a..7148c682ef0 100644
--- a/gcc/config/s390/s390.md
+++ b/gcc/config/s390/s390.md
@@ -10629,6 +10629,7 @@
       case 1:
         if (larl_operand (operands[0], Pmode))
 	  return INTVAL (operands[1]) == 1 ? "pfdrl\t2,%a0" : "pfdrl\t1,%a0";
+	  /* fallthrough */
       default:
 
         /* This might be reached for symbolic operands with an odd