!1489 GPU fix slice

Merge pull request !1489 from VectorSL/gpu-fix-slice

mindspore/ccsrc/kernel/gpu/arrays/slice_gpu_kernel.h

@@ -79,6 +79,9 @@ class SliceGpuFwdKernel : public GpuKernel {
       if (size_[i] < 0) {
         size_[i] = (size_[i] + input_shape_[i]) > 0 ? (size_[i] + input_shape_[i]) : 0;
       }
+      if (size_[i] == 0) {
+        size_[i] = begin_[i] + 1;
+      }
     }
 
     input_size_ = IntToSize(input_shape_[0] * input_shape_[1] * input_shape_[2] * input_shape_[3]) * sizeof(T);

mindspore/ccsrc/kernel/gpu/cuda_impl/slice_impl.cu

@@ -47,7 +47,7 @@ __global__ void SliceGrad(const T* dy, int p, int start, int length, T* output)
 }
 template <typename T>
 __global__ void StridedSlice(const T* input, int p, int start, int begin, int stride, int ended, T* output) {
-  for (size_t pos = blockIdx.x * blockDim.x + threadIdx.x; pos < ((ended - 1 - begin) / stride) + 1;
+  for (size_t pos = blockIdx.x * blockDim.x + threadIdx.x; pos < std::ceil(static_cast<float>(ended - begin) / stride);
        pos += blockDim.x * gridDim.x) {
     output[p + pos] = input[start + pos * stride];
   }
@@ -55,7 +55,7 @@ __global__ void StridedSlice(const T* input, int p, int start, int begin, int st
 }
 template <typename T>
 __global__ void StridedSliceGrad(const T* dy, int p, int start, int begin, int stride, int ended, T* dx) {
-  for (size_t pos = blockIdx.x * blockDim.x + threadIdx.x; pos < ((ended - 1 - begin) / stride) + 1;
+  for (size_t pos = blockIdx.x * blockDim.x + threadIdx.x; pos < std::ceil(static_cast<float>(ended - begin) / stride);
        pos += blockDim.x * gridDim.x) {
     dx[start + pos * stride] = dy[p + pos];
   }
@@ -117,7 +117,7 @@ void CalStridedSlice(const size_t input_size, const T* input, const std::vector<
                 (strides[2] > 0 ? k : 2 * begin[2] - k) * w + begin[3];
         StridedSlice<<<GET_BLOCKS(input_size), GET_THREADS, 0, cuda_stream>>>(input, p, start, begin[3], strides[3],
                                                                               ended, output);
-        p = p + (end[3] - 1 - begin[3]) / strides[3] + 1;
+        p = p + std::ceil(static_cast<float>(end[3] - begin[3]) / strides[3]);
       }
     }
   }
@@ -141,7 +141,7 @@ void CalStridedSliceGrad(const size_t input_size, const T* dy, const std::vector
                 (strides[2] > 0 ? k : 2 * begin[2] - k) * w + begin[3];
         StridedSliceGrad<<<GET_BLOCKS(input_size), GET_THREADS, 0, cuda_stream>>>(dy, p, start, begin[3], strides[3],
                                                                                   ended, dx);
-        p = p + (end[3] - 1 - begin[3]) / strides[3] + 1;
+        p = p + std::ceil(static_cast<float>(end[3] - begin[3]) / strides[3]);
       }
     }
   }