add DataBound struct for reduce_max and reduce_min

Author: AnnaTrainingG

paddle/fluid/operators/reduce_ops/reduce_functor_op.h

@@ -13,10 +13,45 @@ See the License for the specific language governing permissions and
 limitations under the License. */
 
 #pragma once
+#include <cuda.h>
+#include <float.h>
+#include <limits.h>
+#include <math.h>
+#include <cstdint>
 
 namespace paddle {
 namespace operators {
 
+template <typename T>
+struct DataBound {
+  static inline T max() { return static_cast<T>(FLT_MAX); }
+  static inline T min() { return static_cast<T>(-FLT_MAX); }
+};
+
+template <>
+struct DataBound<float> {
+  static inline float max() { return FLT_MAX; }
+  static inline float min() { return -FLT_MAX; }
+};
+
+template <>
+struct DataBound<double> {
+  static inline double max() { return DBL_MAX; }
+  static inline double min() { return -DBL_MAX; }
+};
+
+template <>
+struct DataBound<int32_t> {
+  static inline int32_t max() { return INT32_MAX; }
+  static inline int32_t min() { return INT32_MIN; }
+};
+
+template <>
+struct DataBound<int64_t> {
+  static inline int64_t max() { return INT64_MAX; }
+  static inline int64_t min() { return INT64_MIN; }
+};
+
 template <typename T>
 struct CustomMin {
   __device__ T operator()(const T &a, const T &b) const {

paddle/fluid/operators/reduce_ops/reduce_max_op.cu

@@ -44,7 +44,7 @@ class ReduceMaxKernel : public framework::OpKernel<T> {
 
     auto stream = context.cuda_device_context().stream();
     TensorReduceFunc<T, T, CustomMax<T>, detail::IdentityFunctor<T>>(
-        *input, output, reduce_dims, static_cast<T>(-FLT_MAX), CustomMax<T>(),
+        *input, output, reduce_dims, DataBound<T>::min(), CustomMax<T>(),
         detail::IdentityFunctor<T>(), stream);
   }
 };

paddle/fluid/operators/reduce_ops/reduce_min_op.cu

@@ -44,7 +44,7 @@ class ReduceMinKernel : public framework::OpKernel<T> {
 
     auto stream = context.cuda_device_context().stream();
     TensorReduceFunc<T, T, CustomMin<T>, detail::IdentityFunctor<T>>(
-        *input, output, reduce_dims, static_cast<T>(FLT_MAX), CustomMin<T>(),
+        *input, output, reduce_dims, DataBound<T>::max(), CustomMin<T>(),
         detail::IdentityFunctor<T>(), stream);
   }
 };