fix div 0 error in floormod (PaddlePaddle#49997)

* fix mod 0 error

* fix div 0 error in floormod

paddle/phi/kernels/funcs/elementwise_functor.h

@@ -501,6 +501,7 @@ struct MinGradXYFunctor {
 template <typename T, typename Enable = void>
 struct RemainderFunctor {
   inline HOSTDEVICE T operator()(const T a, const T b) const {
+    PADDLE_ENFORCE(b != 0, DIV_ERROR_INFO);
     T res = a % b;
 
     // Accoding to #PR26732: in dividen % divsor

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

@@ -0,0 +1,35 @@
+#  Copyright (c) 2023 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+import unittest
+
+import paddle
+import paddle.fluid as fluid
+
+
+class TestFloorModOp(unittest.TestCase):
+    def test_dygraph(self):
+        with fluid.dygraph.guard(fluid.CPUPlace()):
+            # mod by zero
+            x = paddle.to_tensor([59], dtype='int32')
+            y = paddle.to_tensor([0], dtype='int32')
+            try:
+                paddle.floor_mod(x, y)
+            except Exception as e:
+                print("Error: Mod by zero encounter in floor_mod\n")
+
+
+if __name__ == '__main__':
+    unittest.main()