Index: lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp =================================================================== --- lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp +++ lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp @@ -2022,7 +2022,7 @@ } /// findNonImmUse - Return true if "Use" is a non-immediate use of "Def". -/// This function recursively traverses up the operand chain, ignoring +/// This function iteratively traverses up the operand chain, ignoring /// certain nodes. static bool findNonImmUse(SDNode *Use, SDNode* Def, SDNode *ImmedUse, SDNode *Root, SmallPtrSetImpl &Visited, @@ -2035,30 +2035,36 @@ // The Use may be -1 (unassigned) if it is a newly allocated node. This can // happen because we scan down to newly selected nodes in the case of glue // uses. - if ((Use->getNodeId() < Def->getNodeId() && Use->getNodeId() != -1)) - return false; + std::vector WorkList; + WorkList.push_back(Use); - // Don't revisit nodes if we already scanned it and didn't fail, we know we - // won't fail if we scan it again. - if (!Visited.insert(Use).second) - return false; + while (!WorkList.empty()) { + Use = WorkList.back(); + WorkList.pop_back(); + if (Use->getNodeId() < Def->getNodeId() && Use->getNodeId() != -1) + continue; - for (const SDValue &Op : Use->op_values()) { - // Ignore chain uses, they are validated by HandleMergeInputChains. - if (Op.getValueType() == MVT::Other && IgnoreChains) + // Don't revisit nodes if we already scanned it and didn't fail, we know we + // won't fail if we scan it again. + if (!Visited.insert(Use).second) continue; - SDNode *N = Op.getNode(); - if (N == Def) { - if (Use == ImmedUse || Use == Root) - continue; // We are not looking for immediate use. - assert(N != Root); - return true; - } + for (const SDValue &Op : Use->op_values()) { + // Ignore chain uses, they are validated by HandleMergeInputChains. + if (Op.getValueType() == MVT::Other && IgnoreChains) + continue; - // Traverse up the operand chain. - if (findNonImmUse(N, Def, ImmedUse, Root, Visited, IgnoreChains)) - return true; + SDNode *N = Op.getNode(); + if (N == Def) { + if (Use == ImmedUse || Use == Root) + continue; // We are not looking for immediate use. + assert(N != Root); + return true; + } + + // Traverse up the operand chain. + WorkList.push_back(N); + } } return false; }