Method BuildGraphWithoutRecurrentTerm

source/opt/scalar_analysis.cpp:433–463

Rebuild the |node| eliminating, if it exists, the recurrent term which belongs to the |loop|.

// Rebuild the |node| eliminating, if it exists, the recurrent term which
// belongs to the |loop|.
SENode* ScalarEvolutionAnalysis::BuildGraphWithoutRecurrentTerm(
    SENode* node, const Loop* loop) {
  // If the node is already a recurrent expression belonging to loop then just
  // return the offset.
  SERecurrentNode* recurrent = node->AsSERecurrentNode();
  if (recurrent) {
    if (recurrent->GetLoop() == loop) {
      return recurrent->GetOffset();
    } else {
      return node;
    }
  }

  std::vector<SENode*> new_children;
  // Otherwise find the recurrent node in the children of this node.
  for (auto itr : *node) {
    recurrent = itr->AsSERecurrentNode();
    if (recurrent && recurrent->GetLoop() == loop) {
      new_children.push_back(recurrent->GetOffset());
    } else {
      new_children.push_back(itr);
    }
  }

  std::unique_ptr<SENode> add_node{new SEAddNode(this)};
  for (SENode* child : new_children) {
    add_node->AddChild(child);
  }

  return SimplifyExpression(GetCachedOrAdd(std::move(add_node)));
}

// Return the recurrent term belonging to |loop| if it appears in the graph
// starting at |node| or null if it doesn't.