make high precision for avg_pool and adaptive_avg_pool when data_type is float16 (#31887)

* make high precision for avg_pool

paddle/fluid/operators/math/pooling.h

@@ -18,6 +18,7 @@ limitations under the License. */
 
 #include "paddle/fluid/framework/eigen.h"
 #include "paddle/fluid/framework/tensor.h"
+#include "paddle/fluid/operators/amp/fp16_type_traits.h"
 #include "paddle/fluid/platform/device_context.h"
 #include "paddle/fluid/platform/hostdevice.h"
 #include "paddle/fluid/platform/macros.h"
@@ -46,10 +47,22 @@ class MaxPool {
 
 template <class T>
 class AvgPool {
+  using MT = typename details::MPTypeTrait<T>::Type;
+  MT intermediate_res;
+
  public:
-  DEVICE inline T initial() { return static_cast<T>(0); }
-  DEVICE inline void compute(const T& x, T* y) { *y += x; }
-  DEVICE inline void finalize(const T& pool_field, T* y) { *y /= pool_field; }
+  DEVICE inline T initial() {
+    intermediate_res = static_cast<MT>(0.0f);
+    return static_cast<T>(0);
+  }
+
+  DEVICE inline void compute(const T& x, T* y) {
+    intermediate_res += static_cast<MT>(x);
+  }
+
+  DEVICE inline void finalize(const T& pool_field, T* y) {
+    *y = static_cast<T>(intermediate_res / (static_cast<MT>(pool_field)));
+  }
 };
 
 template <class T>