Fix round in grid sample op (#27657)

paddle/fluid/operators/grid_sampler_op.cu

@@ -238,9 +238,8 @@ __global__ void grid_sample_cuda_kernel(const int nthreads, int n, int out_c,
         }
       }
     } else if (mode == Mode::nearest) {
-      int ix_nearest = static_cast<int>(round(ix));
-      int iy_nearest = static_cast<int>(round(iy));
-
+      int ix_nearest = static_cast<int>(std::nearbyint(ix));
+      int iy_nearest = static_cast<int>(std::nearbyint(iy));
       auto inp_offset_NC = n * inp_sN;
       auto out_ptr_NCHW = output + n * out_sN + h * out_sH + w * out_sW;
       for (int c = 0; c < out_c;
@@ -403,8 +402,8 @@ __global__ void grid_sampler_cuda_backward_kernel(
         gGrid_ptr_NHW[1] = giy_mult * giy;
       }
     } else if (mode == Mode::nearest) {
-      int ix_nearest = static_cast<int>(::round(ix));
-      int iy_nearest = static_cast<int>(::round(iy));
+      int ix_nearest = static_cast<int>(std::nearbyint(ix));
+      int iy_nearest = static_cast<int>(std::nearbyint(iy));
 
       int gOut_offset = n * gOut_sN + h * gOut_sH + w * gOut_sW;
       T* gInp_ptr_NC = grad_input + n * inp_sN;