Index: lib/CodeGen/SelectionDAG/DAGCombiner.cpp =================================================================== --- lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -10777,6 +10777,34 @@ EVT MemVT = St->getMemoryVT(); unsigned Seq = 0; StoreSDNode *Index = St; + + + bool UseAA = CombinerAA.getNumOccurrences() > 0 ? CombinerAA + : DAG.getSubtarget().useAA(); + + if (UseAA) { + // Look at other users of the same chain. Stores on the same chain do not + // alias. + // TODO: This should be the common (only?) case if combiner-aa is + // enabled. Should we skip or remove the code looking at consecutive chains? + SDValue Chain = St->getChain(); + for (auto I = Chain->use_begin(), E = Chain->use_end(); I != E; ++I) { + if (StoreSDNode *OtherST = dyn_cast(*I)) { + + if (OtherST->isVolatile() || OtherST->isIndexed()) + continue; + + if (OtherST->getMemoryVT() != MemVT) + continue; + + BaseIndexOffset Ptr = BaseIndexOffset::match(OtherST->getBasePtr()); + StoreNodes.push_back(MemOpLink(OtherST, Ptr.Offset, Seq++)); + } + } + + return; + } + while (Index) { // If the chain has more than one use, then we can't reorder the mem ops. if (Index != St && !SDValue(Index, 0)->hasOneUse())