[0-size Tensor Job2 No.68、92] Add 0-size Tensor support for pow (#73204)

* Fix

* Fix

Author: co63oc

test/legacy_test/test_pow.py

@@ -232,5 +232,41 @@ def x_dtype_error():
             self.assertRaises(TypeError, x_dtype_error)
 
 
+class TestPowerAPI_ZeroSize(unittest.TestCase):
+    """TestPowerAPI."""
+
+    def setUp(self):
+        self.places = []
+        if (
+            os.environ.get('FLAGS_CI_both_cpu_and_gpu', 'False').lower()
+            in ['1', 'true', 'on']
+            or not core.is_compiled_with_cuda()
+        ):
+            self.places.append('cpu')
+        if core.is_compiled_with_cuda():
+            self.places.append('gpu')
+
+    def _test_power(self, shape):
+        np.random.seed(7)
+        for place in self.places:
+            dims = shape
+            x = (np.random.rand(*dims) * 10).astype(np.float64)
+            y = np.random.rand() * 10
+            paddle.disable_static()
+            paddle.set_device(place)
+            x_ = paddle.to_tensor(x)
+            x_.stop_gradient = False
+            y_ = y
+            res = paddle.pow(x_, y_)
+            np.testing.assert_allclose(res, np.power(x, y), rtol=1e-05)
+            loss = paddle.sum(res)
+            loss.backward()
+            np.testing.assert_allclose(x_.grad.shape, x_.shape)
+
+    def test_power(self):
+        self._test_power((0, 2))
+        self._test_power((0, 0))
+
+
 if __name__ == '__main__':
     unittest.main()