Fix the compiling error of update_loss_scaling when using cuda9.

Author: wzzju

paddle/fluid/operators/amp/update_loss_scaling_op.h

@@ -14,6 +14,9 @@
 
 #pragma once
 
+#if defined(PADDLE_WITH_CUDA) && defined(__NVCC__)
+#include <cuda.h>
+#endif  // PADDLE_WITH_CUDA && __NVCC__
 #include <cmath>
 #include <vector>
 #include "paddle/fluid/framework/operator.h"
@@ -29,13 +32,23 @@ namespace operators {
 using Tensor = framework::Tensor;
 
 template <typename T>
-HOSTDEVICE void Update(const bool* found_inf_data,
-                       const T* pre_loss_scaling_data, const int* good_in_data,
-                       const int* bad_in_data, const int incr_every_n_steps,
-                       const int decr_every_n_nan_or_inf,
-                       const float incr_ratio, const float decr_ratio,
-                       T* updated_loss_scaling_data, int* good_out_data,
-                       int* bad_out_data) {
+inline HOSTDEVICE bool check_finite(T value) {
+#if defined(PADDLE_WITH_CUDA) && defined(__NVCC__)
+  return isfinite(value);
+#else
+  return std::isfinite(value);
+#endif
+}
+
+template <typename T>
+inline HOSTDEVICE void Update(const bool* found_inf_data,
+                              const T* pre_loss_scaling_data,
+                              const int* good_in_data, const int* bad_in_data,
+                              const int incr_every_n_steps,
+                              const int decr_every_n_nan_or_inf,
+                              const float incr_ratio, const float decr_ratio,
+                              T* updated_loss_scaling_data, int* good_out_data,
+                              int* bad_out_data) {
   if (*found_inf_data) {
     *good_out_data = 0;
     *bad_out_data = *bad_in_data + 1;
@@ -51,7 +64,7 @@ HOSTDEVICE void Update(const bool* found_inf_data,
     *good_out_data = *good_in_data + 1;
     if (*good_out_data == incr_every_n_steps) {
       T new_loss_scaling = *pre_loss_scaling_data * incr_ratio;
-      *updated_loss_scaling_data = std::isfinite(new_loss_scaling)
+      *updated_loss_scaling_data = check_finite(new_loss_scaling)
                                        ? new_loss_scaling
                                        : *pre_loss_scaling_data;
       *good_out_data = 0;