message: Replace powf with pow, and atan2f with atan2.
  gcc doesn't support them.
  Also add the missing header include <cmath>
diff: @@ -13,6 +13,8 @@ See the License for the specific language governing permissions and
  limitations under the License.
  ==============================================================================*/
  +#include <cmath>
  +
  #include "tensorflow/compiler/xla/tests/exhaustive_op_test_utils.h"
  #ifdef __FAST_MATH__
  @@ -122,11 +124,11 @@ BINARY_TEST_16BIT(Min, {
  // TODO(bixia): Pow fails with bfloat16 on CPU.
  BINARY_TEST_16BIT(DISABLED_ON_CPU(Pow),
  - { Run(AddEmptyBroadcastDimension(Pow), std::powf); })
  + { Run(AddEmptyBroadcastDimension(Pow), std::pow); })
  // TODO(bixia): Atan2 fails with bfloat16 on CPU.
  BINARY_TEST_16BIT(DISABLED_ON_CPU(Atan2),
  - { Run(AddEmptyBroadcastDimension(Atan2), std::atan2f); })
  + { Run(AddEmptyBroadcastDimension(Atan2), std::atan2); })
  #if !defined(XLA_BACKEND_DOES_NOT_SUPPORT_FLOAT16)
  INSTANTIATE_TEST_SUITE_P(F16, ExhaustiveF16BinaryTest,
  