From fde47aae610c4319abdfeb245fb402ae6a668028 Mon Sep 17 00:00:00 2001
From: Tomasz Patejko <tomasz.patejko@intel.com>
Date: Tue, 22 May 2018 00:52:00 +0200
Subject: [PATCH] MKL elementwise add backward: grad inputs copied when they
 are not null

---
 paddle/fluid/operators/elementwise_add_op.h | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/paddle/fluid/operators/elementwise_add_op.h b/paddle/fluid/operators/elementwise_add_op.h
index 0bf9600848..3286aa848d 100644
--- a/paddle/fluid/operators/elementwise_add_op.h
+++ b/paddle/fluid/operators/elementwise_add_op.h
@@ -102,13 +102,15 @@ class ElementwiseAddGradKernel : public framework::OpKernel<T> {
     if (platform::is_cpu_place(ctx.GetPlace()) && (x->dims() == y->dims())) {
       auto blas = math::GetBlas<DeviceContext, T>(ctx);
 
-      if (dx)
-        dx->mutable_data<T>(ctx.GetPlace());
-      if (dy)
-        dy->mutable_data<T>(ctx.GetPlace());
-
-      blas.VCOPY(dout->numel(), dout->data<T>(), dx->data<T>());
-      blas.VCOPY(dout->numel(), dout->data<T>(), dy->data<T>());
+      if (dx) {
+        blas.VCOPY(dout->numel(), dout->data<T>(),
+                   dx->mutable_data<T>(ctx.GetPlace()));
+      }
+
+      if (dy) {
+        blas.VCOPY(dout->numel(), dout->data<T>(),
+                   dy->mutable_data<T>(ctx.GetPlace()));
+      }
     } else {
       ElemwiseGradCompute<DeviceContext, T, IdentityGrad<T>, IdentityGrad<T>>(
           ctx, *x, *y, *out, *dout, axis, dx, dy, IdentityGrad<T>(),
-- 
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