arm_compute v20.05
diff --git a/tests/validation/reference/BitwiseNot.cpp b/tests/validation/reference/BitwiseNot.cpp
index 5a6a13b..03578a3 100644
--- a/tests/validation/reference/BitwiseNot.cpp
+++ b/tests/validation/reference/BitwiseNot.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017 ARM Limited.
+ * Copyright (c) 2017-2020 ARM Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -35,7 +35,9 @@
 SimpleTensor<T> bitwise_not(const SimpleTensor<T> &src)
 {
     SimpleTensor<T> dst(src.shape(), src.data_type());
-
+#if defined(_OPENMP)
+    #pragma omp parallel for
+#endif /* _OPENMP */
     for(int i = 0; i < src.num_elements(); ++i)
     {
         dst[i] = ~src[i];