Index: lib/CodeGen/SelectionDAG/DAGCombiner.cpp =================================================================== --- lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -9647,11 +9647,14 @@ return false; // Perform an early exit check. Do not bother looking at stored values that - // are not constants or loads. + // are not constants, loads, or extracted vector elements. SDValue StoredVal = St->getValue(); bool IsLoadSrc = isa(StoredVal); - if (!isa(StoredVal) && !isa(StoredVal) && - !IsLoadSrc) + bool IsConstantSrc = isa(StoredVal) || + isa(StoredVal); + bool IsExtractVecEltSrc = (StoredVal.getOpcode() == ISD::EXTRACT_VECTOR_ELT); + + if (!IsConstantSrc && !IsLoadSrc && !IsExtractVecEltSrc) return false; // Only look at ends of store sequences. @@ -9793,7 +9796,7 @@ LSBaseSDNode *FirstInChain = StoreNodes[0].MemNode; // Store the constants into memory as one consecutive store. - if (!IsLoadSrc) { + if (IsConstantSrc) { unsigned LastLegalType = 0; unsigned LastLegalVectorType = 0; bool NonZero = false; @@ -9923,6 +9926,84 @@ return true; } + // When extracting multiple vector elements, try to store them + // in one vector store rather than a sequence of scalar stores. + if (IsExtractVecEltSrc) { + unsigned NumElem = 0; + for (unsigned i = 0; i < LastConsecutiveStore + 1; ++i) { + StoreSDNode *St = cast(StoreNodes[i].MemNode); + SDValue StoredVal = St->getValue(); + // This restriction could be loosened. + // Bail out if any stored values are not elements extracted from a vector. + // It should be possible to handle mixed sources, but load sources need + // more careful handling (see the block of code below that handles + // consecutive loads). + if (StoredVal.getOpcode() != ISD::EXTRACT_VECTOR_ELT) + return false; + + // Find a legal type for the vector store. + EVT Ty = EVT::getVectorVT(*DAG.getContext(), MemVT, i+1); + if (TLI.isTypeLegal(Ty)) + NumElem = i + 1; + } + + // Make sure we have a legal type and something to merge. + if (NumElem < 2) + return false; + + unsigned EarliestNodeUsed = 0; + for (unsigned i=0; i < NumElem; ++i) { + // Find a chain for the new wide-store operand. Notice that some + // of the store nodes that we found may not be selected for inclusion + // in the wide store. The chain we use needs to be the chain of the + // earliest store node which is *used* and replaced by the wide store. + if (StoreNodes[i].SequenceNum > StoreNodes[EarliestNodeUsed].SequenceNum) + EarliestNodeUsed = i; + } + + // The earliest Node in the DAG. + LSBaseSDNode *EarliestOp = StoreNodes[EarliestNodeUsed].MemNode; + SDLoc DL(StoreNodes[0].MemNode); + + SDValue StoredVal; + + // Find a legal type for the vector store. + EVT Ty = EVT::getVectorVT(*DAG.getContext(), MemVT, NumElem); + + SmallVector Ops; + for (unsigned i = 0; i < NumElem ; ++i) { + StoreSDNode *St = cast(StoreNodes[i].MemNode); + SDValue Val = St->getValue(); + // All of the operands of a BUILD_VECTOR must have the same type. + if (Val.getValueType() != MemVT) + return false; + Ops.push_back(Val); + } + + // Build the extracted vector elements back into a vector. + StoredVal = DAG.getNode(ISD::BUILD_VECTOR, DL, Ty, Ops); + + SDValue NewStore = DAG.getStore(EarliestOp->getChain(), DL, StoredVal, + FirstInChain->getBasePtr(), + FirstInChain->getPointerInfo(), + false, false, + FirstInChain->getAlignment()); + + // Replace the first store with the new store + CombineTo(EarliestOp, NewStore); + // Erase all other stores. + for (unsigned i = 0; i < NumElem ; ++i) { + if (StoreNodes[i].MemNode == EarliestOp) + continue; + StoreSDNode *St = cast(StoreNodes[i].MemNode); + while (!St->use_empty()) + DAG.ReplaceAllUsesWith(SDValue(St, 0), St->getChain()); + deleteAndRecombine(St); + } + + return true; + } + // Below we handle the case of multiple consecutive stores that // come from multiple consecutive loads. We merge them into a single // wide load and a single wide store. Index: test/CodeGen/X86/MergeConsecutiveStores.ll =================================================================== --- test/CodeGen/X86/MergeConsecutiveStores.ll +++ test/CodeGen/X86/MergeConsecutiveStores.ll @@ -434,3 +434,62 @@ ;