compiler warning by elementwise_op.h

[luotao1]

There are a lot of warning caused by elementwise_op.h:

/home/luotao02/Paddle/paddle/operators/elementwise_op.h(205): warning: function "paddle::framework::OperatorBase::InferShape(const paddle::framework::Scope &) const" is hidden by "paddle::operators::ElementwiseOp::InferShape" -- virtual function override intended?

/home/luotao02/Paddle/paddle/operators/elementwise_op.h(287): warning: function "paddle::framework::OperatorBase::InferShape(const paddle::framework::Scope &) const" is hidden by "paddle::operators::ElementwiseOpGrad::InferShape" -- virtual function override intended?

...

[jacquesqiao]

This is because the InferShape of elementwise_op is written in header file and will be processed by nvcc when GPU is enabled, nvcc will throw this warning.