Add a new HandleNode class, which is used to handle (haha) cases in the
dead node elim and dag combiner passes where the root is potentially updated.
This fixes a fixme in the dag combiner.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23634 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 61fa319..d861e15 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -176,7 +176,7 @@
// Create a dummy node (which is not added to allnodes), that adds a reference
// to the root node, preventing it from being deleted.
- SDNode *DummyNode = new SDNode(ISD::EntryToken, getRoot());
+ HandleSDNode Dummy(getRoot());
// If we have a hint to start from, use it.
if (N) DeleteNodeIfDead(N, &AllNodeSet);
@@ -199,11 +199,7 @@
AllNodes.assign(AllNodeSet.begin(), AllNodeSet.end());
// If the root changed (e.g. it was a dead load, update the root).
- setRoot(DummyNode->getOperand(0));
-
- // Now that we are done with the dummy node, delete it.
- DummyNode->getOperand(0).Val->removeUser(DummyNode);
- delete DummyNode;
+ setRoot(Dummy.getValue());
}
@@ -276,6 +272,7 @@
void SelectionDAG::RemoveNodeFromCSEMaps(SDNode *N) {
bool Erased = false;
switch (N->getOpcode()) {
+ case ISD::HANDLENODE: return; // noop.
case ISD::Constant:
Erased = Constants.erase(std::make_pair(cast<ConstantSDNode>(N)->getValue(),
N->getValueType(0)));
@@ -397,6 +394,8 @@
N->getValueType(0)))];
if (L) return L;
L = N;
+ } else if (N->getOpcode() == ISD::HANDLENODE) {
+ return 0; // never add it.
} else if (N->getNumOperands() == 1) {
SDNode *&U = UnaryOps[std::make_pair(N->getOpcode(),
std::make_pair(N->getOperand(0),