add inplace to reshape (#8747)

paddle/fluid/operators/reshape_op.cc

@@ -84,6 +84,9 @@ class ReshapeOpMaker : public framework::OpProtoAndCheckerMaker {
     AddAttr<std::vector<int>>("shape",
                               "(vector<int>) "
                               "Target shape of reshape operator.");
+    AddAttr<bool>("inplace",
+                  "Change the source tensor's shape without copy memory.")
+        .SetDefault(true);
     AddComment(R"DOC(
 Reshape Operator.
 

paddle/fluid/operators/reshape_op.h

@@ -26,10 +26,16 @@ class ReshapeKernel : public framework::OpKernel<T> {
   void Compute(const framework::ExecutionContext& ctx) const {
     auto* out = ctx.Output<framework::Tensor>("Out");
     auto* in = ctx.Input<framework::Tensor>("X");
+    bool inplace = ctx.Attr<bool>("inplace");
     auto out_dims = out->dims();
-    out->mutable_data<T>(ctx.GetPlace());
-    framework::TensorCopy(*in, ctx.GetPlace(), ctx.device_context(), out);
-    out->Resize(out_dims);
+    if (!inplace) {
+      out->mutable_data<T>(ctx.GetPlace());
+      framework::TensorCopy(*in, ctx.GetPlace(), ctx.device_context(), out);
+      out->Resize(out_dims);
+    } else {
+      out->ShareDataWith(*in);
+      out->Resize(out_dims);
+    }
   }
 };
 
@@ -40,10 +46,16 @@ class ReshapeGradKernel : public framework::OpKernel<T> {
     auto* d_out = ctx.Input<framework::Tensor>(framework::GradVarName("Out"));
     auto* d_x = ctx.Output<framework::Tensor>(framework::GradVarName("X"));
     d_x->mutable_data<T>(ctx.GetPlace());
+    bool inplace = ctx.Attr<bool>("inplace");
 
     auto in_dims = d_x->dims();
-    framework::TensorCopy(*d_out, ctx.GetPlace(), ctx.device_context(), d_x);
-    d_x->Resize(in_dims);
+    if (!inplace) {
+      framework::TensorCopy(*d_out, ctx.GetPlace(), ctx.device_context(), d_x);
+      d_x->Resize(in_dims);
+    } else {
+      d_x->ShareDataWith(*d_out);
+      d_x->Resize(in_dims);
+    }
   }
 };
 }  // namespace operators

python/paddle/fluid/tests/unittests/test_reshape_op.py

@@ -45,5 +45,33 @@ class TestReshapeOpDimInfer(OpTest):
         self.check_grad(["X"], "Out")
 
 
+class TestReshapeOpInplace(OpTest):
+    def setUp(self):
+        self.op_type = "reshape"
+        self.inputs = {'X': np.random.random((10, 20)).astype("float32")}
+        self.attrs = {'shape': [10 * 20], 'inplace': True}
+        self.outputs = {'Out': self.inputs['X'].reshape(self.attrs['shape'])}
+
+    def test_check_output(self):
+        self.check_output()
+
+    def test_check_grad(self):
+        self.check_grad(["X"], "Out")
+
+
+class TestReshapeOpDimInferInplace(OpTest):
+    def setUp(self):
+        self.op_type = "reshape"
+        self.inputs = {'X': np.random.random((10, 20)).astype("float32")}
+        self.attrs = {'shape': [4, -1, 5], 'inplace': True}
+        self.outputs = {'Out': self.inputs['X'].reshape(self.attrs['shape'])}
+
+    def test_check_output(self):
+        self.check_output()
+
+    def test_check_grad(self):
+        self.check_grad(["X"], "Out")
+
+
 if __name__ == '__main__':
     unittest.main()