Fix Python IndexError of Case14: paddle.nn.functional.glu (#50016)

* 为split增加取值范围维度的判断

* 为glu的axis进行取值判断并添加单测

* 完善glu的单测

* fix glu

python/paddle/fluid/tests/unittests/test_glu.py

@@ -72,5 +72,15 @@ def test_case(self):
             self.check_identity(fluid.CUDAPlace(0))
 
 
+class TestGlu(unittest.TestCase):
+    def glu_axis_size(self):
+        paddle.enable_static()
+        x = paddle.static.data(name='x', shape=[1, 2, 3], dtype='float32')
+        paddle.nn.functional.glu(x, axis=256)
+
+    def test_errors(self):
+        self.assertRaises(ValueError, self.glu_axis_size)
+
+
 if __name__ == '__main__':
     unittest.main()

python/paddle/nn/functional/activation.py

@@ -1622,6 +1622,13 @@ def glu(x, axis=-1, name=None):
     check_variable_and_dtype(
         x, 'input', ['float16', 'float32', 'float64'], "glu"
     )
+    rank = len(x.shape)
+    if not (-rank <= axis < rank):
+        raise ValueError(
+            "Expected value range of `axis` is [{}, {}), but received axis: {}".format(
+                -rank, rank, axis
+            )
+        )
     a, b = chunk(x, 2, axis=axis, name=name)
     gate = sigmoid(b, name=name)
     out = paddle.multiply(a, gate, name=name)