diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 72f458118da..466e3606070 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -363,6 +363,28 @@ namespace { /// chain (aliasing node.) SDValue FindBetterChain(SDNode *N, SDValue Chain); + /// Holds a pointer to an LSBaseSDNode as well as information on where it + /// is located in a sequence of memory operations connected by a chain. + struct MemOpLink { + MemOpLink (LSBaseSDNode *N, int64_t Offset, unsigned Seq): + MemNode(N), OffsetFromBase(Offset), SequenceNum(Seq) { } + // Ptr to the mem node. + LSBaseSDNode *MemNode; + // Offset from the base ptr. + int64_t OffsetFromBase; + // What is the sequence number of this mem node. + // Lowest mem operand in the DAG starts at zero. + unsigned SequenceNum; + }; + + /// This is a helper function for MergeConsecutiveStores. When the source + /// elements of the consecutive stores are all constants or all extracted + /// vector elements, try to merge them into one larger store. + /// \return True if a merged store was created. + bool MergeStoresOfConstantsOrVecElts(SmallVectorImpl &StoreNodes, + EVT MemVT, unsigned NumElem, + bool IsConstantSrc, bool UseVector); + /// Merge consecutive store operations into a wide store. /// This optimization uses wide integers or vectors when possible. /// \return True if some memory operations were changed. @@ -9706,19 +9728,116 @@ struct BaseIndexOffset { } }; -/// Holds a pointer to an LSBaseSDNode as well as information on where it -/// is located in a sequence of memory operations connected by a chain. -struct MemOpLink { - MemOpLink (LSBaseSDNode *N, int64_t Offset, unsigned Seq): - MemNode(N), OffsetFromBase(Offset), SequenceNum(Seq) { } - // Ptr to the mem node. - LSBaseSDNode *MemNode; - // Offset from the base ptr. - int64_t OffsetFromBase; - // What is the sequence number of this mem node. - // Lowest mem operand in the DAG starts at zero. - unsigned SequenceNum; -}; +bool DAGCombiner::MergeStoresOfConstantsOrVecElts( + SmallVectorImpl &StoreNodes, EVT MemVT, + unsigned NumElem, bool IsConstantSrc, bool UseVector) { + // Make sure we have something to merge. + if (NumElem < 2) + return false; + + int64_t ElementSizeBytes = MemVT.getSizeInBits() / 8; + LSBaseSDNode *FirstInChain = StoreNodes[0].MemNode; + 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; + if (UseVector) { + // Find a legal type for the vector store. + EVT Ty = EVT::getVectorVT(*DAG.getContext(), MemVT, NumElem); + assert(TLI.isTypeLegal(Ty) && "Illegal vector store"); + if (IsConstantSrc) { + // A vector store with a constant source implies that the constant is + // zero; we only handle merging stores of constant zeros because the zero + // can be materialized without a load. + // It may be beneficial to loosen this restriction to allow non-zero + // store merging. + StoredVal = DAG.getConstant(0, Ty); + } else { + 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); + } + } else { + // We should always use a vector store when merging extracted vector + // elements, so this path implies a store of constants. + assert(IsConstantSrc && "Merged vector elements should use vector store"); + + unsigned StoreBW = NumElem * ElementSizeBytes * 8; + APInt StoreInt(StoreBW, 0); + + // Construct a single integer constant which is made of the smaller + // constant inputs. + bool IsLE = TLI.isLittleEndian(); + for (unsigned i = 0; i < NumElem ; ++i) { + unsigned Idx = IsLE ? (NumElem - 1 - i) : i; + StoreSDNode *St = cast(StoreNodes[Idx].MemNode); + SDValue Val = St->getValue(); + StoreInt <<= ElementSizeBytes*8; + if (ConstantSDNode *C = dyn_cast(Val)) { + StoreInt |= C->getAPIntValue().zext(StoreBW); + } else if (ConstantFPSDNode *C = dyn_cast(Val)) { + StoreInt |= C->getValueAPF().bitcastToAPInt().zext(StoreBW); + } else { + llvm_unreachable("Invalid constant element type"); + } + } + + // Create the new Load and Store operations. + EVT StoreTy = EVT::getIntegerVT(*DAG.getContext(), StoreBW); + StoredVal = DAG.getConstant(StoreInt, StoreTy); + } + + 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); + // ReplaceAllUsesWith will replace all uses that existed when it was + // called, but graph optimizations may cause new ones to appear. For + // example, the case in pr14333 looks like + // + // St's chain -> St -> another store -> X + // + // And the only difference from St to the other store is the chain. + // When we change it's chain to be St's chain they become identical, + // get CSEed and the net result is that X is now a use of St. + // Since we know that St is redundant, just iterate. + while (!St->use_empty()) + DAG.ReplaceAllUsesWith(SDValue(St, 0), St->getChain()); + deleteAndRecombine(St); + } + + return true; +} bool DAGCombiner::MergeConsecutiveStores(StoreSDNode* St) { EVT MemVT = St->getMemoryVT(); @@ -9731,11 +9850,14 @@ bool DAGCombiner::MergeConsecutiveStores(StoreSDNode* St) { 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. @@ -9877,7 +9999,7 @@ bool DAGCombiner::MergeConsecutiveStores(StoreSDNode* St) { 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; @@ -9926,85 +10048,33 @@ bool DAGCombiner::MergeConsecutiveStores(StoreSDNode* St) { bool UseVector = (LastLegalVectorType > LastLegalType) && !NoVectors; unsigned NumElem = UseVector ? LastLegalVectorType : LastLegalType; - // Make sure we have something to merge. - if (NumElem < 2) - return false; + return MergeStoresOfConstantsOrVecElts(StoreNodes, MemVT, NumElem, + true, UseVector); + } - 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; - if (UseVector) { + // 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, NumElem); - assert(TLI.isTypeLegal(Ty) && "Illegal vector store"); - StoredVal = DAG.getConstant(0, Ty); - } else { - unsigned StoreBW = NumElem * ElementSizeBytes * 8; - APInt StoreInt(StoreBW, 0); - - // Construct a single integer constant which is made of the smaller - // constant inputs. - bool IsLE = TLI.isLittleEndian(); - for (unsigned i = 0; i < NumElem ; ++i) { - unsigned Idx = IsLE ?(NumElem - 1 - i) : i; - StoreSDNode *St = cast(StoreNodes[Idx].MemNode); - SDValue Val = St->getValue(); - StoreInt<<=ElementSizeBytes*8; - if (ConstantSDNode *C = dyn_cast(Val)) { - StoreInt|=C->getAPIntValue().zext(StoreBW); - } else if (ConstantFPSDNode *C = dyn_cast(Val)) { - StoreInt|= C->getValueAPF().bitcastToAPInt().zext(StoreBW); - } else { - llvm_unreachable("Invalid constant element type"); - } - } - - // Create the new Load and Store operations. - EVT StoreTy = EVT::getIntegerVT(*DAG.getContext(), StoreBW); - StoredVal = DAG.getConstant(StoreInt, StoreTy); + EVT Ty = EVT::getVectorVT(*DAG.getContext(), MemVT, i+1); + if (TLI.isTypeLegal(Ty)) + NumElem = i + 1; } - 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); - // ReplaceAllUsesWith will replace all uses that existed when it was - // called, but graph optimizations may cause new ones to appear. For - // example, the case in pr14333 looks like - // - // St's chain -> St -> another store -> X - // - // And the only difference from St to the other store is the chain. - // When we change it's chain to be St's chain they become identical, - // get CSEed and the net result is that X is now a use of St. - // Since we know that St is redundant, just iterate. - while (!St->use_empty()) - DAG.ReplaceAllUsesWith(SDValue(St, 0), St->getChain()); - deleteAndRecombine(St); - } - - return true; + return MergeStoresOfConstantsOrVecElts(StoreNodes, MemVT, NumElem, + false, true); } // Below we handle the case of multiple consecutive stores that diff --git a/test/CodeGen/X86/MergeConsecutiveStores.ll b/test/CodeGen/X86/MergeConsecutiveStores.ll index dfdaea523fd..f396e88f54c 100644 --- a/test/CodeGen/X86/MergeConsecutiveStores.ll +++ b/test/CodeGen/X86/MergeConsecutiveStores.ll @@ -434,3 +434,62 @@ define void @loadStoreBaseIndexOffsetSextNoSex(i8* %a, i8* %b, i8* %c, i32 %n) { ;