diff --git a/libgomp/ChangeLog b/libgomp/ChangeLog
index b53dc6b7056..6071b239f1f 100644
--- a/libgomp/ChangeLog
+++ b/libgomp/ChangeLog
@@ -1,3 +1,8 @@
+2016-04-12  Thomas Schwinge  <thomas@codesourcery.com>
+
+	* testsuite/libgomp.oacc-c-c++-common/par-loop-comb-reduction-2.c:
+	Make failure observable.
+
 2016-04-12  Jakub Jelinek  <jakub@redhat.com>
 
 	* libgomp.h (struct gomp_target_task): Remove firstprivate_copies
diff --git a/libgomp/testsuite/libgomp.oacc-c-c++-common/par-loop-comb-reduction-2.c b/libgomp/testsuite/libgomp.oacc-c-c++-common/par-loop-comb-reduction-2.c
index a7a75a94104..a339f327956 100644
--- a/libgomp/testsuite/libgomp.oacc-c-c++-common/par-loop-comb-reduction-2.c
+++ b/libgomp/testsuite/libgomp.oacc-c-c++-common/par-loop-comb-reduction-2.c
@@ -19,7 +19,7 @@ main (int argc, char *argv[])
       {
 	#pragma acc loop worker vector reduction(^:res)
 	for (i = 0; i < 1024; i++)
-	  res ^= arr[j * 1024 + i];
+	  res ^= 3 * arr[j * 1024 + i];
 
 	#pragma acc loop worker vector reduction(^:res)
 	for (i = 0; i < 1024; i++)
@@ -30,7 +30,7 @@ main (int argc, char *argv[])
   for (j = 0; j < 32; j++)
     for (i = 0; i < 1024; i++)
       {
-        hres ^= arr[j * 1024 + i];
+	hres ^= 3 * arr[j * 1024 + i];
 	hres ^= arr[j * 1024 + (1023 - i)];
       }