From 0fe9c6e7babb3c0731d9cb864ec498ec4184760f Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Mon, 7 Jul 2008 20:57:48 +0000 Subject: [PATCH] Fix SDNode::MorphNodeTo (a function used by by SelectNodeTo) to properly track dead nodes that are on the original SDNode's operand list but not the new one, and have no other uses. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53201 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/CodeGen/SelectionDAG.h | 5 ++ include/llvm/CodeGen/SelectionDAGNodes.h | 8 +- lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 99 ++++++++++++----------- 3 files changed, 65 insertions(+), 47 deletions(-) diff --git a/include/llvm/CodeGen/SelectionDAG.h b/include/llvm/CodeGen/SelectionDAG.h index 6568d90951d..56bd40ae5ce 100644 --- a/include/llvm/CodeGen/SelectionDAG.h +++ b/include/llvm/CodeGen/SelectionDAG.h @@ -537,6 +537,11 @@ public: /// for each node deleted. void RemoveDeadNode(SDNode *N, DAGUpdateListener *UpdateListener = 0); + /// RemoveDeadNodes - This method deletes the unreachable nodes in the + /// given list, and any nodes that become unreachable as a result. + void RemoveDeadNodes(SmallVectorImpl &DeadNodes, + DAGUpdateListener *UpdateListener = 0); + /// ReplaceAllUsesWith - Modify anything using 'From' to use 'To' instead. /// This can cause recursive merging of nodes in the DAG. Use the first /// version if 'From' is known to have a single result, use the second diff --git a/include/llvm/CodeGen/SelectionDAGNodes.h b/include/llvm/CodeGen/SelectionDAGNodes.h index f5ab0707c40..fe1cab6fe6b 100644 --- a/include/llvm/CodeGen/SelectionDAGNodes.h +++ b/include/llvm/CodeGen/SelectionDAGNodes.h @@ -1315,12 +1315,18 @@ protected: ++Ops[i].getVal()->UsesSize; } } + + /// DropOperands - Release the operands and set this node to have + /// zero operands. This should only be used by HandleSDNode to clear + /// its operand list. + void DropOperands(); /// MorphNodeTo - This frees the operands of the current node, resets the /// opcode, types, and operands to the specified value. This should only be /// used by the SelectionDAG class. void MorphNodeTo(unsigned Opc, SDVTList L, - const SDOperand *Ops, unsigned NumOps); + const SDOperand *Ops, unsigned NumOps, + SmallVectorImpl &DeadNodes); void addUser(unsigned i, SDNode *User) { assert(User->OperandList[i].getUser() && "Node without parent"); diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index b9f84080ba8..3f262df713f 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -486,12 +486,26 @@ void SelectionDAG::RemoveDeadNodes() { if (I->use_empty()) DeadNodes.push_back(I); + RemoveDeadNodes(DeadNodes); + + // If the root changed (e.g. it was a dead load, update the root). + setRoot(Dummy.getValue()); +} + +/// RemoveDeadNodes - This method deletes the unreachable nodes in the +/// given list, and any nodes that become unreachable as a result. +void SelectionDAG::RemoveDeadNodes(SmallVectorImpl &DeadNodes, + DAGUpdateListener *UpdateListener) { + // Process the worklist, deleting the nodes and adding their uses to the // worklist. while (!DeadNodes.empty()) { SDNode *N = DeadNodes.back(); DeadNodes.pop_back(); + if (UpdateListener) + UpdateListener->NodeDeleted(N, 0); + // Take the node out of the appropriate CSE map. RemoveNodeFromCSEMaps(N); @@ -514,49 +528,12 @@ void SelectionDAG::RemoveDeadNodes() { // Finally, remove N itself. AllNodes.erase(N); } - - // If the root changed (e.g. it was a dead load, update the root). - setRoot(Dummy.getValue()); } void SelectionDAG::RemoveDeadNode(SDNode *N, DAGUpdateListener *UpdateListener){ SmallVector 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(); - - if (UpdateListener) - UpdateListener->NodeDeleted(N, 0); - - // 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. - unsigned op_num = 0; - for (SDNode::op_iterator I = N->op_begin(), E = N->op_end(); I != E; ++I) { - SDNode *Operand = I->getVal(); - Operand->removeUser(op_num, N); - - // Now that we removed this operand, see if there are no uses of it left. - if (Operand->use_empty()) - DeadNodes.push_back(Operand); - - op_num++; - } - if (N->OperandsNeedDelete) { - delete[] N->OperandList; - } - N->OperandList = 0; - N->NumOperands = 0; - - // Finally, remove N itself. - AllNodes.erase(N); - } + RemoveDeadNodes(DeadNodes, UpdateListener); } void SelectionDAG::DeleteNode(SDNode *N) { @@ -3681,16 +3658,22 @@ UpdateNodeOperands(SDOperand InN, const SDOperand *Ops, unsigned NumOps) { /// opcode, types, and operands to the specified value. This should only be /// used by the SelectionDAG class. void SDNode::MorphNodeTo(unsigned Opc, SDVTList L, - const SDOperand *Ops, unsigned NumOps) { + const SDOperand *Ops, unsigned NumOps, + SmallVectorImpl &DeadNodes) { NodeType = Opc; ValueList = L.VTs; NumValues = L.NumVTs; // Clear the operands list, updating used nodes to remove this from their - // use list. - for (op_iterator I = op_begin(), E = op_end(); I != E; ++I) - I->getVal()->removeUser(std::distance(op_begin(), I), this); - + // use list. Keep track of any operands that become dead as a result. + SmallPtrSet DeadNodeSet; + for (op_iterator I = op_begin(), E = op_end(); I != E; ++I) { + SDNode *N = I->getVal(); + N->removeUser(std::distance(op_begin(), I), this); + if (N->use_empty()) + DeadNodeSet.insert(N); + } + // If NumOps is larger than the # of operands we currently have, reallocate // the operand list. if (NumOps > NumOperands) { @@ -3710,7 +3693,29 @@ void SDNode::MorphNodeTo(unsigned Opc, SDVTList L, SDNode *N = OperandList[i].getVal(); N->addUser(i, this); ++N->UsesSize; + DeadNodeSet.erase(N); } + + // Clean up any nodes that are still dead after adding the uses for the + // new operands. + for (SmallPtrSet::iterator I = DeadNodeSet.begin(), + E = DeadNodeSet.end(); I != E; ++I) + DeadNodes.push_back(*I); +} + +/// DropOperands - Release the operands and set this node to have +/// zero operands. This should only be used by HandleSDNode to clear +/// its operand list. +void SDNode::DropOperands() { + assert(NodeType == ISD::HANDLENODE && + "DropOperands is for HANDLENODE only!"); + + // Unlike the code in MorphNodeTo that does this, we don't need to + // watch for dead nodes here. + for (op_iterator I = op_begin(), E = op_end(); I != E; ++I) + I->getVal()->removeUser(std::distance(op_begin(), I), this); + + NumOperands = 0; } /// SelectNodeTo - These are used for target selectors to *mutate* the @@ -3814,7 +3819,10 @@ SDNode *SelectionDAG::SelectNodeTo(SDNode *N, unsigned TargetOpc, RemoveNodeFromCSEMaps(N); - N->MorphNodeTo(ISD::BUILTIN_OP_END+TargetOpc, VTs, Ops, NumOps); + SmallVector DeadNodes; + N->MorphNodeTo(ISD::BUILTIN_OP_END+TargetOpc, VTs, Ops, NumOps, DeadNodes); + RemoveDeadNodes(DeadNodes); + CSEMap.InsertNode(N, IP); // Memoize the new node. return N; } @@ -4250,8 +4258,7 @@ void StoreSDNode::ANCHOR() {} void AtomicSDNode::ANCHOR() {} HandleSDNode::~HandleSDNode() { - SDVTList VTs = { 0, 0 }; - MorphNodeTo(ISD::HANDLENODE, VTs, 0, 0); // Drops operand uses. + DropOperands(); } GlobalAddressSDNode::GlobalAddressSDNode(bool isTarget, const GlobalValue *GA,