// Copyright (c) 2021 Graphcore Ltd. All rights reserved.
#ifndef POPART_WILLOW_SRC_TRANSFORMS_AUTODIFF_GRADNONGRADPAIR_HPP_
#define POPART_WILLOW_SRC_TRANSFORMS_AUTODIFF_GRADNONGRADPAIR_HPP_

namespace popart {
class Op;

// helper class used during backwards pass construction.
// This class helps to decouple the non-grad op from a
// grad op (previously grad ops kept a pointer to a non-grad
// op, which was dangerous as optimisations remove ops)
class GradNonGradPair {
public:
  Op *grad;
  Op *nongrad;
  GradNonGradPair(Op *g_, Op *ng_);
  GradNonGradPair();
};

} // namespace popart

#endif // POPART_WILLOW_SRC_TRANSFORMS_AUTODIFF_GRADNONGRADPAIR_HPP_