[llvm-commits] CVS: llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

[Evan Cheng]

Changes in directory llvm/lib/CodeGen/SelectionDAG:

SelectionDAG.cpp updated: 1.348 -> 1.349
---
Log message:

Add RemoveDeadNode to remove a dead node and its (potentially) dead operands.

---
Diffs of the changes:  (+33 -0)

 SelectionDAG.cpp |   33 +++++++++++++++++++++++++++++++++
 1 files changed, 33 insertions(+)


Index: llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
diff -u llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:1.348 llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:1.349
--- llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:1.348	Wed Oct 11 02:09:31 2006
+++ llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp	Thu Oct 12 15:34:05 2006
@@ -300,6 +300,39 @@
   setRoot(Dummy.getValue());
 }
 
+void SelectionDAG::RemoveDeadNode(SDNode *N, std::vector<SDNode*> &Deleted) {
+  SmallVector<SDNode*, 16> DeadNodes;
+  DeadNodes.push_back(N);
+
+  // Process the worklist, deleting the nodes and adding their uses to the
+  // worklist.
+  while (!DeadNodes.empty()) {
+    SDNode *N = DeadNodes.back();
+    DeadNodes.pop_back();
+    
+    // Take the node out of the appropriate CSE map.
+    RemoveNodeFromCSEMaps(N);
+
+    // Next, brutally remove the operand list.  This is safe to do, as there are
+    // no cycles in the graph.
+    for (SDNode::op_iterator I = N->op_begin(), E = N->op_end(); I != E; ++I) {
+      SDNode *Operand = I->Val;
+      Operand->removeUser(N);
+      
+      // Now that we removed this operand, see if there are no uses of it left.
+      if (Operand->use_empty())
+        DeadNodes.push_back(Operand);
+    }
+    delete[] N->OperandList;
+    N->OperandList = 0;
+    N->NumOperands = 0;
+    
+    // Finally, remove N itself.
+    Deleted.push_back(N);
+    AllNodes.erase(N);
+  }
+}
+
 void SelectionDAG::DeleteNode(SDNode *N) {
   assert(N->use_empty() && "Cannot delete a node that is not dead!");