Merge branch 'refine_elementwise_add' of https://github.com/sneaxiy/Paddle into refine_elementwise_add

paddle/fluid/operators/elementwise_add_op.h

@@ -141,8 +141,6 @@ class ElementwiseAddGradKernel : public framework::OpKernel<T> {
   void Compute(const framework::ExecutionContext& ctx) const override {
     using Tensor = framework::Tensor;
 
-    auto* x = ctx.Input<Tensor>("X");
-    auto* y = ctx.Input<Tensor>("Y");
     auto* dout = ctx.Input<Tensor>(framework::GradVarName("Out"));
     auto* dx = ctx.Output<Tensor>(framework::GradVarName("X"));
     auto* dy = ctx.Output<Tensor>(framework::GradVarName("Y"));
@@ -150,13 +148,13 @@ class ElementwiseAddGradKernel : public framework::OpKernel<T> {
     if (dx != nullptr) dx->ShareDataWith(*dout);
     if (dy == nullptr) return;
 
-    if (x->dims() == y->dims()) {
+    const framework::DDim& x_dim = dout->dims();
+    framework::DDim y_dim = dy->dims();
+    if (x_dim == y_dim) {
       dy->ShareDataWith(*dout);
     } else {
       dy->mutable_data<T>(ctx.GetPlace());
       // Perform reduction to dout to calculate dy
-      const framework::DDim& x_dim = x->dims();
-      framework::DDim y_dim = y->dims();
       int axis = ctx.Attr<int>("axis");
       axis = (axis == -1 ? x_dim.size() - y_dim.size() : axis);
       y_dim = trim_trailing_singular_dims(y_dim);