//===-- DAGCombiner.cpp - Implement a DAG node combiner -------------------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This pass combines dag nodes to form fewer, simpler DAG nodes. It can be run // both before and after the DAG is legalized. // // This pass is not a substitute for the LLVM IR instcombine pass. This pass is // primarily intended to handle simplification opportunities that are implicit // in the LLVM IR and exposed by the various codegen lowering phases. // //===----------------------------------------------------------------------===// #define DEBUG_TYPE "dagcombine" #include "llvm/CodeGen/SelectionDAG.h" #include "llvm/DerivedTypes.h" #include "llvm/LLVMContext.h" #include "llvm/CodeGen/MachineFunction.h" #include "llvm/CodeGen/MachineFrameInfo.h" #include "llvm/CodeGen/PseudoSourceValue.h" #include "llvm/Analysis/AliasAnalysis.h" #include "llvm/Target/TargetData.h" #include "llvm/Target/TargetLowering.h" #include "llvm/Target/TargetMachine.h" #include "llvm/Target/TargetOptions.h" #include "llvm/ADT/SmallPtrSet.h" #include "llvm/ADT/Statistic.h" #include "llvm/Support/CommandLine.h" #include "llvm/Support/Debug.h" #include "llvm/Support/ErrorHandling.h" #include "llvm/Support/MathExtras.h" #include "llvm/Support/raw_ostream.h" #include using namespace llvm; STATISTIC(NodesCombined , "Number of dag nodes combined"); STATISTIC(PreIndexedNodes , "Number of pre-indexed nodes created"); STATISTIC(PostIndexedNodes, "Number of post-indexed nodes created"); STATISTIC(OpsNarrowed , "Number of load/op/store narrowed"); STATISTIC(LdStFP2Int , "Number of fp load/store pairs transformed to int"); namespace { static cl::opt CombinerAA("combiner-alias-analysis", cl::Hidden, cl::desc("Turn on alias analysis during testing")); static cl::opt CombinerGlobalAA("combiner-global-alias-analysis", cl::Hidden, cl::desc("Include global information in alias analysis")); //------------------------------ DAGCombiner ---------------------------------// class DAGCombiner { SelectionDAG &DAG; const TargetLowering &TLI; CombineLevel Level; CodeGenOpt::Level OptLevel; bool LegalOperations; bool LegalTypes; // Worklist of all of the nodes that need to be simplified. std::vector WorkList; // AA - Used for DAG load/store alias analysis. AliasAnalysis &AA; /// AddUsersToWorkList - When an instruction is simplified, add all users of /// the instruction to the work lists because they might get more simplified /// now. /// void AddUsersToWorkList(SDNode *N) { for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end(); UI != UE; ++UI) AddToWorkList(*UI); } /// visit - call the node-specific routine that knows how to fold each /// particular type of node. SDValue visit(SDNode *N); public: /// AddToWorkList - Add to the work list making sure it's instance is at the /// the back (next to be processed.) void AddToWorkList(SDNode *N) { removeFromWorkList(N); WorkList.push_back(N); } /// removeFromWorkList - remove all instances of N from the worklist. /// void removeFromWorkList(SDNode *N) { WorkList.erase(std::remove(WorkList.begin(), WorkList.end(), N), WorkList.end()); } SDValue CombineTo(SDNode *N, const SDValue *To, unsigned NumTo, bool AddTo = true); SDValue CombineTo(SDNode *N, SDValue Res, bool AddTo = true) { return CombineTo(N, &Res, 1, AddTo); } SDValue CombineTo(SDNode *N, SDValue Res0, SDValue Res1, bool AddTo = true) { SDValue To[] = { Res0, Res1 }; return CombineTo(N, To, 2, AddTo); } void CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &TLO); private: /// SimplifyDemandedBits - Check the specified integer node value to see if /// it can be simplified or if things it uses can be simplified by bit /// propagation. If so, return true. bool SimplifyDemandedBits(SDValue Op) { unsigned BitWidth = Op.getValueType().getScalarType().getSizeInBits(); APInt Demanded = APInt::getAllOnesValue(BitWidth); return SimplifyDemandedBits(Op, Demanded); } bool SimplifyDemandedBits(SDValue Op, const APInt &Demanded); bool CombineToPreIndexedLoadStore(SDNode *N); bool CombineToPostIndexedLoadStore(SDNode *N); void ReplaceLoadWithPromotedLoad(SDNode *Load, SDNode *ExtLoad); SDValue PromoteOperand(SDValue Op, EVT PVT, bool &Replace); SDValue SExtPromoteOperand(SDValue Op, EVT PVT); SDValue ZExtPromoteOperand(SDValue Op, EVT PVT); SDValue PromoteIntBinOp(SDValue Op); SDValue PromoteIntShiftOp(SDValue Op); SDValue PromoteExtend(SDValue Op); bool PromoteLoad(SDValue Op); /// combine - call the node-specific routine that knows how to fold each /// particular type of node. If that doesn't do anything, try the /// target-specific DAG combines. SDValue combine(SDNode *N); // Visitation implementation - Implement dag node combining for different // node types. The semantics are as follows: // Return Value: // SDValue.getNode() == 0 - No change was made // SDValue.getNode() == N - N was replaced, is dead and has been handled. // otherwise - N should be replaced by the returned Operand. // SDValue visitTokenFactor(SDNode *N); SDValue visitMERGE_VALUES(SDNode *N); SDValue visitADD(SDNode *N); SDValue visitSUB(SDNode *N); SDValue visitADDC(SDNode *N); SDValue visitADDE(SDNode *N); SDValue visitMUL(SDNode *N); SDValue visitSDIV(SDNode *N); SDValue visitUDIV(SDNode *N); SDValue visitSREM(SDNode *N); SDValue visitUREM(SDNode *N); SDValue visitMULHU(SDNode *N); SDValue visitMULHS(SDNode *N); SDValue visitSMUL_LOHI(SDNode *N); SDValue visitUMUL_LOHI(SDNode *N); SDValue visitSDIVREM(SDNode *N); SDValue visitUDIVREM(SDNode *N); SDValue visitAND(SDNode *N); SDValue visitOR(SDNode *N); SDValue visitXOR(SDNode *N); SDValue SimplifyVBinOp(SDNode *N); SDValue visitSHL(SDNode *N); SDValue visitSRA(SDNode *N); SDValue visitSRL(SDNode *N); SDValue visitCTLZ(SDNode *N); SDValue visitCTTZ(SDNode *N); SDValue visitCTPOP(SDNode *N); SDValue visitSELECT(SDNode *N); SDValue visitSELECT_CC(SDNode *N); SDValue visitSETCC(SDNode *N); SDValue visitSIGN_EXTEND(SDNode *N); SDValue visitZERO_EXTEND(SDNode *N); SDValue visitANY_EXTEND(SDNode *N); SDValue visitSIGN_EXTEND_INREG(SDNode *N); SDValue visitTRUNCATE(SDNode *N); SDValue visitBITCAST(SDNode *N); SDValue visitBUILD_PAIR(SDNode *N); SDValue visitFADD(SDNode *N); SDValue visitFSUB(SDNode *N); SDValue visitFMUL(SDNode *N); SDValue visitFDIV(SDNode *N); SDValue visitFREM(SDNode *N); SDValue visitFCOPYSIGN(SDNode *N); SDValue visitSINT_TO_FP(SDNode *N); SDValue visitUINT_TO_FP(SDNode *N); SDValue visitFP_TO_SINT(SDNode *N); SDValue visitFP_TO_UINT(SDNode *N); SDValue visitFP_ROUND(SDNode *N); SDValue visitFP_ROUND_INREG(SDNode *N); SDValue visitFP_EXTEND(SDNode *N); SDValue visitFNEG(SDNode *N); SDValue visitFABS(SDNode *N); SDValue visitBRCOND(SDNode *N); SDValue visitBR_CC(SDNode *N); SDValue visitLOAD(SDNode *N); SDValue visitSTORE(SDNode *N); SDValue visitINSERT_VECTOR_ELT(SDNode *N); SDValue visitEXTRACT_VECTOR_ELT(SDNode *N); SDValue visitBUILD_VECTOR(SDNode *N); SDValue visitCONCAT_VECTORS(SDNode *N); SDValue visitVECTOR_SHUFFLE(SDNode *N); SDValue visitMEMBARRIER(SDNode *N); SDValue XformToShuffleWithZero(SDNode *N); SDValue ReassociateOps(unsigned Opc, DebugLoc DL, SDValue LHS, SDValue RHS); SDValue visitShiftByConstant(SDNode *N, unsigned Amt); bool SimplifySelectOps(SDNode *SELECT, SDValue LHS, SDValue RHS); SDValue SimplifyBinOpWithSameOpcodeHands(SDNode *N); SDValue SimplifySelect(DebugLoc DL, SDValue N0, SDValue N1, SDValue N2); SDValue SimplifySelectCC(DebugLoc DL, SDValue N0, SDValue N1, SDValue N2, SDValue N3, ISD::CondCode CC, bool NotExtCompare = false); SDValue SimplifySetCC(EVT VT, SDValue N0, SDValue N1, ISD::CondCode Cond, DebugLoc DL, bool foldBooleans = true); SDValue SimplifyNodeWithTwoResults(SDNode *N, unsigned LoOp, unsigned HiOp); SDValue CombineConsecutiveLoads(SDNode *N, EVT VT); SDValue ConstantFoldBITCASTofBUILD_VECTOR(SDNode *, EVT); SDValue BuildSDIV(SDNode *N); SDValue BuildUDIV(SDNode *N); SDNode *MatchRotate(SDValue LHS, SDValue RHS, DebugLoc DL); SDValue ReduceLoadWidth(SDNode *N); SDValue ReduceLoadOpStoreWidth(SDNode *N); SDValue TransformFPLoadStorePair(SDNode *N); SDValue GetDemandedBits(SDValue V, const APInt &Mask); /// GatherAllAliases - Walk up chain skipping non-aliasing memory nodes, /// looking for aliasing nodes and adding them to the Aliases vector. void GatherAllAliases(SDNode *N, SDValue OriginalChain, SmallVector &Aliases); /// isAlias - Return true if there is any possibility that the two addresses /// overlap. bool isAlias(SDValue Ptr1, int64_t Size1, const Value *SrcValue1, int SrcValueOffset1, unsigned SrcValueAlign1, const MDNode *TBAAInfo1, SDValue Ptr2, int64_t Size2, const Value *SrcValue2, int SrcValueOffset2, unsigned SrcValueAlign2, const MDNode *TBAAInfo2) const; /// FindAliasInfo - Extracts the relevant alias information from the memory /// node. Returns true if the operand was a load. bool FindAliasInfo(SDNode *N, SDValue &Ptr, int64_t &Size, const Value *&SrcValue, int &SrcValueOffset, unsigned &SrcValueAlignment, const MDNode *&TBAAInfo) const; /// FindBetterChain - Walk up chain skipping non-aliasing memory nodes, /// looking for a better chain (aliasing node.) SDValue FindBetterChain(SDNode *N, SDValue Chain); public: DAGCombiner(SelectionDAG &D, AliasAnalysis &A, CodeGenOpt::Level OL) : DAG(D), TLI(D.getTargetLoweringInfo()), Level(Unrestricted), OptLevel(OL), LegalOperations(false), LegalTypes(false), AA(A) {} /// Run - runs the dag combiner on all nodes in the work list void Run(CombineLevel AtLevel); SelectionDAG &getDAG() const { return DAG; } /// getShiftAmountTy - Returns a type large enough to hold any valid /// shift amount - before type legalization these can be huge. EVT getShiftAmountTy(EVT LHSTy) { return LegalTypes ? TLI.getShiftAmountTy(LHSTy) : TLI.getPointerTy(); } /// isTypeLegal - This method returns true if we are running before type /// legalization or if the specified VT is legal. bool isTypeLegal(const EVT &VT) { if (!LegalTypes) return true; return TLI.isTypeLegal(VT); } }; } namespace { /// WorkListRemover - This class is a DAGUpdateListener that removes any deleted /// nodes from the worklist. class WorkListRemover : public SelectionDAG::DAGUpdateListener { DAGCombiner &DC; public: explicit WorkListRemover(DAGCombiner &dc) : DC(dc) {} virtual void NodeDeleted(SDNode *N, SDNode *E) { DC.removeFromWorkList(N); } virtual void NodeUpdated(SDNode *N) { // Ignore updates. } }; } //===----------------------------------------------------------------------===// // TargetLowering::DAGCombinerInfo implementation //===----------------------------------------------------------------------===// void TargetLowering::DAGCombinerInfo::AddToWorklist(SDNode *N) { ((DAGCombiner*)DC)->AddToWorkList(N); } SDValue TargetLowering::DAGCombinerInfo:: CombineTo(SDNode *N, const std::vector &To, bool AddTo) { return ((DAGCombiner*)DC)->CombineTo(N, &To[0], To.size(), AddTo); } SDValue TargetLowering::DAGCombinerInfo:: CombineTo(SDNode *N, SDValue Res, bool AddTo) { return ((DAGCombiner*)DC)->CombineTo(N, Res, AddTo); } SDValue TargetLowering::DAGCombinerInfo:: CombineTo(SDNode *N, SDValue Res0, SDValue Res1, bool AddTo) { return ((DAGCombiner*)DC)->CombineTo(N, Res0, Res1, AddTo); } void TargetLowering::DAGCombinerInfo:: CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &TLO) { return ((DAGCombiner*)DC)->CommitTargetLoweringOpt(TLO); } //===----------------------------------------------------------------------===// // Helper Functions //===----------------------------------------------------------------------===// /// isNegatibleForFree - Return 1 if we can compute the negated form of the /// specified expression for the same cost as the expression itself, or 2 if we /// can compute the negated form more cheaply than the expression itself. static char isNegatibleForFree(SDValue Op, bool LegalOperations, unsigned Depth = 0) { // No compile time optimizations on this type. if (Op.getValueType() == MVT::ppcf128) return 0; // fneg is removable even if it has multiple uses. if (Op.getOpcode() == ISD::FNEG) return 2; // Don't allow anything with multiple uses. if (!Op.hasOneUse()) return 0; // Don't recurse exponentially. if (Depth > 6) return 0; switch (Op.getOpcode()) { default: return false; case ISD::ConstantFP: // Don't invert constant FP values after legalize. The negated constant // isn't necessarily legal. return LegalOperations ? 0 : 1; case ISD::FADD: // FIXME: determine better conditions for this xform. if (!UnsafeFPMath) return 0; // fold (fsub (fadd A, B)) -> (fsub (fneg A), B) if (char V = isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1)) return V; // fold (fneg (fadd A, B)) -> (fsub (fneg B), A) return isNegatibleForFree(Op.getOperand(1), LegalOperations, Depth+1); case ISD::FSUB: // We can't turn -(A-B) into B-A when we honor signed zeros. if (!UnsafeFPMath) return 0; // fold (fneg (fsub A, B)) -> (fsub B, A) return 1; case ISD::FMUL: case ISD::FDIV: if (HonorSignDependentRoundingFPMath()) return 0; // fold (fneg (fmul X, Y)) -> (fmul (fneg X), Y) or (fmul X, (fneg Y)) if (char V = isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1)) return V; return isNegatibleForFree(Op.getOperand(1), LegalOperations, Depth+1); case ISD::FP_EXTEND: case ISD::FP_ROUND: case ISD::FSIN: return isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1); } } /// GetNegatedExpression - If isNegatibleForFree returns true, this function /// returns the newly negated expression. static SDValue GetNegatedExpression(SDValue Op, SelectionDAG &DAG, bool LegalOperations, unsigned Depth = 0) { // fneg is removable even if it has multiple uses. if (Op.getOpcode() == ISD::FNEG) return Op.getOperand(0); // Don't allow anything with multiple uses. assert(Op.hasOneUse() && "Unknown reuse!"); assert(Depth <= 6 && "GetNegatedExpression doesn't match isNegatibleForFree"); switch (Op.getOpcode()) { default: llvm_unreachable("Unknown code"); case ISD::ConstantFP: { APFloat V = cast(Op)->getValueAPF(); V.changeSign(); return DAG.getConstantFP(V, Op.getValueType()); } case ISD::FADD: // FIXME: determine better conditions for this xform. assert(UnsafeFPMath); // fold (fneg (fadd A, B)) -> (fsub (fneg A), B) if (isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1)) return DAG.getNode(ISD::FSUB, Op.getDebugLoc(), Op.getValueType(), GetNegatedExpression(Op.getOperand(0), DAG, LegalOperations, Depth+1), Op.getOperand(1)); // fold (fneg (fadd A, B)) -> (fsub (fneg B), A) return DAG.getNode(ISD::FSUB, Op.getDebugLoc(), Op.getValueType(), GetNegatedExpression(Op.getOperand(1), DAG, LegalOperations, Depth+1), Op.getOperand(0)); case ISD::FSUB: // We can't turn -(A-B) into B-A when we honor signed zeros. assert(UnsafeFPMath); // fold (fneg (fsub 0, B)) -> B if (ConstantFPSDNode *N0CFP = dyn_cast(Op.getOperand(0))) if (N0CFP->getValueAPF().isZero()) return Op.getOperand(1); // fold (fneg (fsub A, B)) -> (fsub B, A) return DAG.getNode(ISD::FSUB, Op.getDebugLoc(), Op.getValueType(), Op.getOperand(1), Op.getOperand(0)); case ISD::FMUL: case ISD::FDIV: assert(!HonorSignDependentRoundingFPMath()); // fold (fneg (fmul X, Y)) -> (fmul (fneg X), Y) if (isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1)) return DAG.getNode(Op.getOpcode(), Op.getDebugLoc(), Op.getValueType(), GetNegatedExpression(Op.getOperand(0), DAG, LegalOperations, Depth+1), Op.getOperand(1)); // fold (fneg (fmul X, Y)) -> (fmul X, (fneg Y)) return DAG.getNode(Op.getOpcode(), Op.getDebugLoc(), Op.getValueType(), Op.getOperand(0), GetNegatedExpression(Op.getOperand(1), DAG, LegalOperations, Depth+1)); case ISD::FP_EXTEND: case ISD::FSIN: return DAG.getNode(Op.getOpcode(), Op.getDebugLoc(), Op.getValueType(), GetNegatedExpression(Op.getOperand(0), DAG, LegalOperations, Depth+1)); case ISD::FP_ROUND: return DAG.getNode(ISD::FP_ROUND, Op.getDebugLoc(), Op.getValueType(), GetNegatedExpression(Op.getOperand(0), DAG, LegalOperations, Depth+1), Op.getOperand(1)); } } // isSetCCEquivalent - Return true if this node is a setcc, or is a select_cc // that selects between the values 1 and 0, making it equivalent to a setcc. // Also, set the incoming LHS, RHS, and CC references to the appropriate // nodes based on the type of node we are checking. This simplifies life a // bit for the callers. static bool isSetCCEquivalent(SDValue N, SDValue &LHS, SDValue &RHS, SDValue &CC) { if (N.getOpcode() == ISD::SETCC) { LHS = N.getOperand(0); RHS = N.getOperand(1); CC = N.getOperand(2); return true; } if (N.getOpcode() == ISD::SELECT_CC && N.getOperand(2).getOpcode() == ISD::Constant && N.getOperand(3).getOpcode() == ISD::Constant && cast(N.getOperand(2))->getAPIntValue() == 1 && cast(N.getOperand(3))->isNullValue()) { LHS = N.getOperand(0); RHS = N.getOperand(1); CC = N.getOperand(4); return true; } return false; } // isOneUseSetCC - Return true if this is a SetCC-equivalent operation with only // one use. If this is true, it allows the users to invert the operation for // free when it is profitable to do so. static bool isOneUseSetCC(SDValue N) { SDValue N0, N1, N2; if (isSetCCEquivalent(N, N0, N1, N2) && N.getNode()->hasOneUse()) return true; return false; } SDValue DAGCombiner::ReassociateOps(unsigned Opc, DebugLoc DL, SDValue N0, SDValue N1) { EVT VT = N0.getValueType(); if (N0.getOpcode() == Opc && isa(N0.getOperand(1))) { if (isa(N1)) { // reassoc. (op (op x, c1), c2) -> (op x, (op c1, c2)) SDValue OpNode = DAG.FoldConstantArithmetic(Opc, VT, cast(N0.getOperand(1)), cast(N1)); return DAG.getNode(Opc, DL, VT, N0.getOperand(0), OpNode); } else if (N0.hasOneUse()) { // reassoc. (op (op x, c1), y) -> (op (op x, y), c1) iff x+c1 has one use SDValue OpNode = DAG.getNode(Opc, N0.getDebugLoc(), VT, N0.getOperand(0), N1); AddToWorkList(OpNode.getNode()); return DAG.getNode(Opc, DL, VT, OpNode, N0.getOperand(1)); } } if (N1.getOpcode() == Opc && isa(N1.getOperand(1))) { if (isa(N0)) { // reassoc. (op c2, (op x, c1)) -> (op x, (op c1, c2)) SDValue OpNode = DAG.FoldConstantArithmetic(Opc, VT, cast(N1.getOperand(1)), cast(N0)); return DAG.getNode(Opc, DL, VT, N1.getOperand(0), OpNode); } else if (N1.hasOneUse()) { // reassoc. (op y, (op x, c1)) -> (op (op x, y), c1) iff x+c1 has one use SDValue OpNode = DAG.getNode(Opc, N0.getDebugLoc(), VT, N1.getOperand(0), N0); AddToWorkList(OpNode.getNode()); return DAG.getNode(Opc, DL, VT, OpNode, N1.getOperand(1)); } } return SDValue(); } SDValue DAGCombiner::CombineTo(SDNode *N, const SDValue *To, unsigned NumTo, bool AddTo) { assert(N->getNumValues() == NumTo && "Broken CombineTo call!"); ++NodesCombined; DEBUG(dbgs() << "\nReplacing.1 "; N->dump(&DAG); dbgs() << "\nWith: "; To[0].getNode()->dump(&DAG); dbgs() << " and " << NumTo-1 << " other values\n"; for (unsigned i = 0, e = NumTo; i != e; ++i) assert((!To[i].getNode() || N->getValueType(i) == To[i].getValueType()) && "Cannot combine value to value of different type!")); WorkListRemover DeadNodes(*this); DAG.ReplaceAllUsesWith(N, To, &DeadNodes); if (AddTo) { // Push the new nodes and any users onto the worklist for (unsigned i = 0, e = NumTo; i != e; ++i) { if (To[i].getNode()) { AddToWorkList(To[i].getNode()); AddUsersToWorkList(To[i].getNode()); } } } // Finally, if the node is now dead, remove it from the graph. The node // may not be dead if the replacement process recursively simplified to // something else needing this node. if (N->use_empty()) { // Nodes can be reintroduced into the worklist. Make sure we do not // process a node that has been replaced. removeFromWorkList(N); // Finally, since the node is now dead, remove it from the graph. DAG.DeleteNode(N); } return SDValue(N, 0); } void DAGCombiner:: CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &TLO) { // Replace all uses. If any nodes become isomorphic to other nodes and // are deleted, make sure to remove them from our worklist. WorkListRemover DeadNodes(*this); DAG.ReplaceAllUsesOfValueWith(TLO.Old, TLO.New, &DeadNodes); // Push the new node and any (possibly new) users onto the worklist. AddToWorkList(TLO.New.getNode()); AddUsersToWorkList(TLO.New.getNode()); // Finally, if the node is now dead, remove it from the graph. The node // may not be dead if the replacement process recursively simplified to // something else needing this node. if (TLO.Old.getNode()->use_empty()) { removeFromWorkList(TLO.Old.getNode()); // If the operands of this node are only used by the node, they will now // be dead. Make sure to visit them first to delete dead nodes early. for (unsigned i = 0, e = TLO.Old.getNode()->getNumOperands(); i != e; ++i) if (TLO.Old.getNode()->getOperand(i).getNode()->hasOneUse()) AddToWorkList(TLO.Old.getNode()->getOperand(i).getNode()); DAG.DeleteNode(TLO.Old.getNode()); } } /// SimplifyDemandedBits - Check the specified integer node value to see if /// it can be simplified or if things it uses can be simplified by bit /// propagation. If so, return true. bool DAGCombiner::SimplifyDemandedBits(SDValue Op, const APInt &Demanded) { TargetLowering::TargetLoweringOpt TLO(DAG, LegalTypes, LegalOperations); APInt KnownZero, KnownOne; if (!TLI.SimplifyDemandedBits(Op, Demanded, KnownZero, KnownOne, TLO)) return false; // Revisit the node. AddToWorkList(Op.getNode()); // Replace the old value with the new one. ++NodesCombined; DEBUG(dbgs() << "\nReplacing.2 "; TLO.Old.getNode()->dump(&DAG); dbgs() << "\nWith: "; TLO.New.getNode()->dump(&DAG); dbgs() << '\n'); CommitTargetLoweringOpt(TLO); return true; } void DAGCombiner::ReplaceLoadWithPromotedLoad(SDNode *Load, SDNode *ExtLoad) { DebugLoc dl = Load->getDebugLoc(); EVT VT = Load->getValueType(0); SDValue Trunc = DAG.getNode(ISD::TRUNCATE, dl, VT, SDValue(ExtLoad, 0)); DEBUG(dbgs() << "\nReplacing.9 "; Load->dump(&DAG); dbgs() << "\nWith: "; Trunc.getNode()->dump(&DAG); dbgs() << '\n'); WorkListRemover DeadNodes(*this); DAG.ReplaceAllUsesOfValueWith(SDValue(Load, 0), Trunc, &DeadNodes); DAG.ReplaceAllUsesOfValueWith(SDValue(Load, 1), SDValue(ExtLoad, 1), &DeadNodes); removeFromWorkList(Load); DAG.DeleteNode(Load); AddToWorkList(Trunc.getNode()); } SDValue DAGCombiner::PromoteOperand(SDValue Op, EVT PVT, bool &Replace) { Replace = false; DebugLoc dl = Op.getDebugLoc(); if (LoadSDNode *LD = dyn_cast(Op)) { EVT MemVT = LD->getMemoryVT(); ISD::LoadExtType ExtType = ISD::isNON_EXTLoad(LD) ? (TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT) ? ISD::ZEXTLOAD : ISD::EXTLOAD) : LD->getExtensionType(); Replace = true; return DAG.getExtLoad(ExtType, dl, PVT, LD->getChain(), LD->getBasePtr(), LD->getPointerInfo(), MemVT, LD->isVolatile(), LD->isNonTemporal(), LD->getAlignment()); } unsigned Opc = Op.getOpcode(); switch (Opc) { default: break; case ISD::AssertSext: return DAG.getNode(ISD::AssertSext, dl, PVT, SExtPromoteOperand(Op.getOperand(0), PVT), Op.getOperand(1)); case ISD::AssertZext: return DAG.getNode(ISD::AssertZext, dl, PVT, ZExtPromoteOperand(Op.getOperand(0), PVT), Op.getOperand(1)); case ISD::Constant: { unsigned ExtOpc = Op.getValueType().isByteSized() ? ISD::SIGN_EXTEND : ISD::ZERO_EXTEND; return DAG.getNode(ExtOpc, dl, PVT, Op); } } if (!TLI.isOperationLegal(ISD::ANY_EXTEND, PVT)) return SDValue(); return DAG.getNode(ISD::ANY_EXTEND, dl, PVT, Op); } SDValue DAGCombiner::SExtPromoteOperand(SDValue Op, EVT PVT) { if (!TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, PVT)) return SDValue(); EVT OldVT = Op.getValueType(); DebugLoc dl = Op.getDebugLoc(); bool Replace = false; SDValue NewOp = PromoteOperand(Op, PVT, Replace); if (NewOp.getNode() == 0) return SDValue(); AddToWorkList(NewOp.getNode()); if (Replace) ReplaceLoadWithPromotedLoad(Op.getNode(), NewOp.getNode()); return DAG.getNode(ISD::SIGN_EXTEND_INREG, dl, NewOp.getValueType(), NewOp, DAG.getValueType(OldVT)); } SDValue DAGCombiner::ZExtPromoteOperand(SDValue Op, EVT PVT) { EVT OldVT = Op.getValueType(); DebugLoc dl = Op.getDebugLoc(); bool Replace = false; SDValue NewOp = PromoteOperand(Op, PVT, Replace); if (NewOp.getNode() == 0) return SDValue(); AddToWorkList(NewOp.getNode()); if (Replace) ReplaceLoadWithPromotedLoad(Op.getNode(), NewOp.getNode()); return DAG.getZeroExtendInReg(NewOp, dl, OldVT); } /// PromoteIntBinOp - Promote the specified integer binary operation if the /// target indicates it is beneficial. e.g. On x86, it's usually better to /// promote i16 operations to i32 since i16 instructions are longer. SDValue DAGCombiner::PromoteIntBinOp(SDValue Op) { if (!LegalOperations) return SDValue(); EVT VT = Op.getValueType(); if (VT.isVector() || !VT.isInteger()) return SDValue(); // If operation type is 'undesirable', e.g. i16 on x86, consider // promoting it. unsigned Opc = Op.getOpcode(); if (TLI.isTypeDesirableForOp(Opc, VT)) return SDValue(); EVT PVT = VT; // Consult target whether it is a good idea to promote this operation and // what's the right type to promote it to. if (TLI.IsDesirableToPromoteOp(Op, PVT)) { assert(PVT != VT && "Don't know what type to promote to!"); bool Replace0 = false; SDValue N0 = Op.getOperand(0); SDValue NN0 = PromoteOperand(N0, PVT, Replace0); if (NN0.getNode() == 0) return SDValue(); bool Replace1 = false; SDValue N1 = Op.getOperand(1); SDValue NN1; if (N0 == N1) NN1 = NN0; else { NN1 = PromoteOperand(N1, PVT, Replace1); if (NN1.getNode() == 0) return SDValue(); } AddToWorkList(NN0.getNode()); if (NN1.getNode()) AddToWorkList(NN1.getNode()); if (Replace0) ReplaceLoadWithPromotedLoad(N0.getNode(), NN0.getNode()); if (Replace1) ReplaceLoadWithPromotedLoad(N1.getNode(), NN1.getNode()); DEBUG(dbgs() << "\nPromoting "; Op.getNode()->dump(&DAG)); DebugLoc dl = Op.getDebugLoc(); return DAG.getNode(ISD::TRUNCATE, dl, VT, DAG.getNode(Opc, dl, PVT, NN0, NN1)); } return SDValue(); } /// PromoteIntShiftOp - Promote the specified integer shift operation if the /// target indicates it is beneficial. e.g. On x86, it's usually better to /// promote i16 operations to i32 since i16 instructions are longer. SDValue DAGCombiner::PromoteIntShiftOp(SDValue Op) { if (!LegalOperations) return SDValue(); EVT VT = Op.getValueType(); if (VT.isVector() || !VT.isInteger()) return SDValue(); // If operation type is 'undesirable', e.g. i16 on x86, consider // promoting it. unsigned Opc = Op.getOpcode(); if (TLI.isTypeDesirableForOp(Opc, VT)) return SDValue(); EVT PVT = VT; // Consult target whether it is a good idea to promote this operation and // what's the right type to promote it to. if (TLI.IsDesirableToPromoteOp(Op, PVT)) { assert(PVT != VT && "Don't know what type to promote to!"); bool Replace = false; SDValue N0 = Op.getOperand(0); if (Opc == ISD::SRA) N0 = SExtPromoteOperand(Op.getOperand(0), PVT); else if (Opc == ISD::SRL) N0 = ZExtPromoteOperand(Op.getOperand(0), PVT); else N0 = PromoteOperand(N0, PVT, Replace); if (N0.getNode() == 0) return SDValue(); AddToWorkList(N0.getNode()); if (Replace) ReplaceLoadWithPromotedLoad(Op.getOperand(0).getNode(), N0.getNode()); DEBUG(dbgs() << "\nPromoting "; Op.getNode()->dump(&DAG)); DebugLoc dl = Op.getDebugLoc(); return DAG.getNode(ISD::TRUNCATE, dl, VT, DAG.getNode(Opc, dl, PVT, N0, Op.getOperand(1))); } return SDValue(); } SDValue DAGCombiner::PromoteExtend(SDValue Op) { if (!LegalOperations) return SDValue(); EVT VT = Op.getValueType(); if (VT.isVector() || !VT.isInteger()) return SDValue(); // If operation type is 'undesirable', e.g. i16 on x86, consider // promoting it. unsigned Opc = Op.getOpcode(); if (TLI.isTypeDesirableForOp(Opc, VT)) return SDValue(); EVT PVT = VT; // Consult target whether it is a good idea to promote this operation and // what's the right type to promote it to. if (TLI.IsDesirableToPromoteOp(Op, PVT)) { assert(PVT != VT && "Don't know what type to promote to!"); // fold (aext (aext x)) -> (aext x) // fold (aext (zext x)) -> (zext x) // fold (aext (sext x)) -> (sext x) DEBUG(dbgs() << "\nPromoting "; Op.getNode()->dump(&DAG)); return DAG.getNode(Op.getOpcode(), Op.getDebugLoc(), VT, Op.getOperand(0)); } return SDValue(); } bool DAGCombiner::PromoteLoad(SDValue Op) { if (!LegalOperations) return false; EVT VT = Op.getValueType(); if (VT.isVector() || !VT.isInteger()) return false; // If operation type is 'undesirable', e.g. i16 on x86, consider // promoting it. unsigned Opc = Op.getOpcode(); if (TLI.isTypeDesirableForOp(Opc, VT)) return false; EVT PVT = VT; // Consult target whether it is a good idea to promote this operation and // what's the right type to promote it to. if (TLI.IsDesirableToPromoteOp(Op, PVT)) { assert(PVT != VT && "Don't know what type to promote to!"); DebugLoc dl = Op.getDebugLoc(); SDNode *N = Op.getNode(); LoadSDNode *LD = cast(N); EVT MemVT = LD->getMemoryVT(); ISD::LoadExtType ExtType = ISD::isNON_EXTLoad(LD) ? (TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT) ? ISD::ZEXTLOAD : ISD::EXTLOAD) : LD->getExtensionType(); SDValue NewLD = DAG.getExtLoad(ExtType, dl, PVT, LD->getChain(), LD->getBasePtr(), LD->getPointerInfo(), MemVT, LD->isVolatile(), LD->isNonTemporal(), LD->getAlignment()); SDValue Result = DAG.getNode(ISD::TRUNCATE, dl, VT, NewLD); DEBUG(dbgs() << "\nPromoting "; N->dump(&DAG); dbgs() << "\nTo: "; Result.getNode()->dump(&DAG); dbgs() << '\n'); WorkListRemover DeadNodes(*this); DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result, &DeadNodes); DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), NewLD.getValue(1), &DeadNodes); removeFromWorkList(N); DAG.DeleteNode(N); AddToWorkList(Result.getNode()); return true; } return false; } //===----------------------------------------------------------------------===// // Main DAG Combiner implementation //===----------------------------------------------------------------------===// void DAGCombiner::Run(CombineLevel AtLevel) { // set the instance variables, so that the various visit routines may use it. Level = AtLevel; LegalOperations = Level >= NoIllegalOperations; LegalTypes = Level >= NoIllegalTypes; // Add all the dag nodes to the worklist. WorkList.reserve(DAG.allnodes_size()); for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(), E = DAG.allnodes_end(); I != E; ++I) WorkList.push_back(I); // Create a dummy node (which is not added to allnodes), that adds a reference // to the root node, preventing it from being deleted, and tracking any // changes of the root. HandleSDNode Dummy(DAG.getRoot()); // The root of the dag may dangle to deleted nodes until the dag combiner is // done. Set it to null to avoid confusion. DAG.setRoot(SDValue()); // while the worklist isn't empty, inspect the node on the end of it and // try and combine it. while (!WorkList.empty()) { SDNode *N = WorkList.back(); WorkList.pop_back(); // If N has no uses, it is dead. Make sure to revisit all N's operands once // N is deleted from the DAG, since they too may now be dead or may have a // reduced number of uses, allowing other xforms. if (N->use_empty() && N != &Dummy) { for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) AddToWorkList(N->getOperand(i).getNode()); DAG.DeleteNode(N); continue; } SDValue RV = combine(N); if (RV.getNode() == 0) continue; ++NodesCombined; // If we get back the same node we passed in, rather than a new node or // zero, we know that the node must have defined multiple values and // CombineTo was used. Since CombineTo takes care of the worklist // mechanics for us, we have no work to do in this case. if (RV.getNode() == N) continue; assert(N->getOpcode() != ISD::DELETED_NODE && RV.getNode()->getOpcode() != ISD::DELETED_NODE && "Node was deleted but visit returned new node!"); DEBUG(dbgs() << "\nReplacing.3 "; N->dump(&DAG); dbgs() << "\nWith: "; RV.getNode()->dump(&DAG); dbgs() << '\n'); WorkListRemover DeadNodes(*this); if (N->getNumValues() == RV.getNode()->getNumValues()) DAG.ReplaceAllUsesWith(N, RV.getNode(), &DeadNodes); else { assert(N->getValueType(0) == RV.getValueType() && N->getNumValues() == 1 && "Type mismatch"); SDValue OpV = RV; DAG.ReplaceAllUsesWith(N, &OpV, &DeadNodes); } // Push the new node and any users onto the worklist AddToWorkList(RV.getNode()); AddUsersToWorkList(RV.getNode()); // Add any uses of the old node to the worklist in case this node is the // last one that uses them. They may become dead after this node is // deleted. for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) AddToWorkList(N->getOperand(i).getNode()); // Finally, if the node is now dead, remove it from the graph. The node // may not be dead if the replacement process recursively simplified to // something else needing this node. if (N->use_empty()) { // Nodes can be reintroduced into the worklist. Make sure we do not // process a node that has been replaced. removeFromWorkList(N); // Finally, since the node is now dead, remove it from the graph. DAG.DeleteNode(N); } } // If the root changed (e.g. it was a dead load, update the root). DAG.setRoot(Dummy.getValue()); } SDValue DAGCombiner::visit(SDNode *N) { switch (N->getOpcode()) { default: break; case ISD::TokenFactor: return visitTokenFactor(N); case ISD::MERGE_VALUES: return visitMERGE_VALUES(N); case ISD::ADD: return visitADD(N); case ISD::SUB: return visitSUB(N); case ISD::ADDC: return visitADDC(N); case ISD::ADDE: return visitADDE(N); case ISD::MUL: return visitMUL(N); case ISD::SDIV: return visitSDIV(N); case ISD::UDIV: return visitUDIV(N); case ISD::SREM: return visitSREM(N); case ISD::UREM: return visitUREM(N); case ISD::MULHU: return visitMULHU(N); case ISD::MULHS: return visitMULHS(N); case ISD::SMUL_LOHI: return visitSMUL_LOHI(N); case ISD::UMUL_LOHI: return visitUMUL_LOHI(N); case ISD::SDIVREM: return visitSDIVREM(N); case ISD::UDIVREM: return visitUDIVREM(N); case ISD::AND: return visitAND(N); case ISD::OR: return visitOR(N); case ISD::XOR: return visitXOR(N); case ISD::SHL: return visitSHL(N); case ISD::SRA: return visitSRA(N); case ISD::SRL: return visitSRL(N); case ISD::CTLZ: return visitCTLZ(N); case ISD::CTTZ: return visitCTTZ(N); case ISD::CTPOP: return visitCTPOP(N); case ISD::SELECT: return visitSELECT(N); case ISD::SELECT_CC: return visitSELECT_CC(N); case ISD::SETCC: return visitSETCC(N); case ISD::SIGN_EXTEND: return visitSIGN_EXTEND(N); case ISD::ZERO_EXTEND: return visitZERO_EXTEND(N); case ISD::ANY_EXTEND: return visitANY_EXTEND(N); case ISD::SIGN_EXTEND_INREG: return visitSIGN_EXTEND_INREG(N); case ISD::TRUNCATE: return visitTRUNCATE(N); case ISD::BITCAST: return visitBITCAST(N); case ISD::BUILD_PAIR: return visitBUILD_PAIR(N); case ISD::FADD: return visitFADD(N); case ISD::FSUB: return visitFSUB(N); case ISD::FMUL: return visitFMUL(N); case ISD::FDIV: return visitFDIV(N); case ISD::FREM: return visitFREM(N); case ISD::FCOPYSIGN: return visitFCOPYSIGN(N); case ISD::SINT_TO_FP: return visitSINT_TO_FP(N); case ISD::UINT_TO_FP: return visitUINT_TO_FP(N); case ISD::FP_TO_SINT: return visitFP_TO_SINT(N); case ISD::FP_TO_UINT: return visitFP_TO_UINT(N); case ISD::FP_ROUND: return visitFP_ROUND(N); case ISD::FP_ROUND_INREG: return visitFP_ROUND_INREG(N); case ISD::FP_EXTEND: return visitFP_EXTEND(N); case ISD::FNEG: return visitFNEG(N); case ISD::FABS: return visitFABS(N); case ISD::BRCOND: return visitBRCOND(N); case ISD::BR_CC: return visitBR_CC(N); case ISD::LOAD: return visitLOAD(N); case ISD::STORE: return visitSTORE(N); case ISD::INSERT_VECTOR_ELT: return visitINSERT_VECTOR_ELT(N); case ISD::EXTRACT_VECTOR_ELT: return visitEXTRACT_VECTOR_ELT(N); case ISD::BUILD_VECTOR: return visitBUILD_VECTOR(N); case ISD::CONCAT_VECTORS: return visitCONCAT_VECTORS(N); case ISD::VECTOR_SHUFFLE: return visitVECTOR_SHUFFLE(N); case ISD::MEMBARRIER: return visitMEMBARRIER(N); } return SDValue(); } SDValue DAGCombiner::combine(SDNode *N) { SDValue RV = visit(N); // If nothing happened, try a target-specific DAG combine. if (RV.getNode() == 0) { assert(N->getOpcode() != ISD::DELETED_NODE && "Node was deleted but visit returned NULL!"); if (N->getOpcode() >= ISD::BUILTIN_OP_END || TLI.hasTargetDAGCombine((ISD::NodeType)N->getOpcode())) { // Expose the DAG combiner to the target combiner impls. TargetLowering::DAGCombinerInfo DagCombineInfo(DAG, !LegalTypes, !LegalOperations, false, this); RV = TLI.PerformDAGCombine(N, DagCombineInfo); } } // If nothing happened still, try promoting the operation. if (RV.getNode() == 0) { switch (N->getOpcode()) { default: break; case ISD::ADD: case ISD::SUB: case ISD::MUL: case ISD::AND: case ISD::OR: case ISD::XOR: RV = PromoteIntBinOp(SDValue(N, 0)); break; case ISD::SHL: case ISD::SRA: case ISD::SRL: RV = PromoteIntShiftOp(SDValue(N, 0)); break; case ISD::SIGN_EXTEND: case ISD::ZERO_EXTEND: case ISD::ANY_EXTEND: RV = PromoteExtend(SDValue(N, 0)); break; case ISD::LOAD: if (PromoteLoad(SDValue(N, 0))) RV = SDValue(N, 0); break; } } // If N is a commutative binary node, try commuting it to enable more // sdisel CSE. if (RV.getNode() == 0 && SelectionDAG::isCommutativeBinOp(N->getOpcode()) && N->getNumValues() == 1) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); // Constant operands are canonicalized to RHS. if (isa(N0) || !isa(N1)) { SDValue Ops[] = { N1, N0 }; SDNode *CSENode = DAG.getNodeIfExists(N->getOpcode(), N->getVTList(), Ops, 2); if (CSENode) return SDValue(CSENode, 0); } } return RV; } /// getInputChainForNode - Given a node, return its input chain if it has one, /// otherwise return a null sd operand. static SDValue getInputChainForNode(SDNode *N) { if (unsigned NumOps = N->getNumOperands()) { if (N->getOperand(0).getValueType() == MVT::Other) return N->getOperand(0); else if (N->getOperand(NumOps-1).getValueType() == MVT::Other) return N->getOperand(NumOps-1); for (unsigned i = 1; i < NumOps-1; ++i) if (N->getOperand(i).getValueType() == MVT::Other) return N->getOperand(i); } return SDValue(); } SDValue DAGCombiner::visitTokenFactor(SDNode *N) { // If N has two operands, where one has an input chain equal to the other, // the 'other' chain is redundant. if (N->getNumOperands() == 2) { if (getInputChainForNode(N->getOperand(0).getNode()) == N->getOperand(1)) return N->getOperand(0); if (getInputChainForNode(N->getOperand(1).getNode()) == N->getOperand(0)) return N->getOperand(1); } SmallVector TFs; // List of token factors to visit. SmallVector Ops; // Ops for replacing token factor. SmallPtrSet SeenOps; bool Changed = false; // If we should replace this token factor. // Start out with this token factor. TFs.push_back(N); // Iterate through token factors. The TFs grows when new token factors are // encountered. for (unsigned i = 0; i < TFs.size(); ++i) { SDNode *TF = TFs[i]; // Check each of the operands. for (unsigned i = 0, ie = TF->getNumOperands(); i != ie; ++i) { SDValue Op = TF->getOperand(i); switch (Op.getOpcode()) { case ISD::EntryToken: // Entry tokens don't need to be added to the list. They are // rededundant. Changed = true; break; case ISD::TokenFactor: if (Op.hasOneUse() && std::find(TFs.begin(), TFs.end(), Op.getNode()) == TFs.end()) { // Queue up for processing. TFs.push_back(Op.getNode()); // Clean up in case the token factor is removed. AddToWorkList(Op.getNode()); Changed = true; break; } // Fall thru default: // Only add if it isn't already in the list. if (SeenOps.insert(Op.getNode())) Ops.push_back(Op); else Changed = true; break; } } } SDValue Result; // If we've change things around then replace token factor. if (Changed) { if (Ops.empty()) { // The entry token is the only possible outcome. Result = DAG.getEntryNode(); } else { // New and improved token factor. Result = DAG.getNode(ISD::TokenFactor, N->getDebugLoc(), MVT::Other, &Ops[0], Ops.size()); } // Don't add users to work list. return CombineTo(N, Result, false); } return Result; } /// MERGE_VALUES can always be eliminated. SDValue DAGCombiner::visitMERGE_VALUES(SDNode *N) { WorkListRemover DeadNodes(*this); // Replacing results may cause a different MERGE_VALUES to suddenly // be CSE'd with N, and carry its uses with it. Iterate until no // uses remain, to ensure that the node can be safely deleted. do { for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) DAG.ReplaceAllUsesOfValueWith(SDValue(N, i), N->getOperand(i), &DeadNodes); } while (!N->use_empty()); removeFromWorkList(N); DAG.DeleteNode(N); return SDValue(N, 0); // Return N so it doesn't get rechecked! } static SDValue combineShlAddConstant(DebugLoc DL, SDValue N0, SDValue N1, SelectionDAG &DAG) { EVT VT = N0.getValueType(); SDValue N00 = N0.getOperand(0); SDValue N01 = N0.getOperand(1); ConstantSDNode *N01C = dyn_cast(N01); if (N01C && N00.getOpcode() == ISD::ADD && N00.getNode()->hasOneUse() && isa(N00.getOperand(1))) { // fold (add (shl (add x, c1), c2), ) -> (add (add (shl x, c2), c1<(V.getOperand(0)); return C && C->isNullValue() && V.getOperand(0) == V.getOperand(1); } SDValue DAGCombiner::visitADD(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); ConstantSDNode *N0C = dyn_cast(N0); ConstantSDNode *N1C = dyn_cast(N1); EVT VT = N0.getValueType(); // fold vector ops if (VT.isVector()) { SDValue FoldedVOp = SimplifyVBinOp(N); if (FoldedVOp.getNode()) return FoldedVOp; } // fold (add x, undef) -> undef if (N0.getOpcode() == ISD::UNDEF) return N0; if (N1.getOpcode() == ISD::UNDEF) return N1; // fold (add c1, c2) -> c1+c2 if (N0C && N1C) return DAG.FoldConstantArithmetic(ISD::ADD, VT, N0C, N1C); // canonicalize constant to RHS if (N0C && !N1C) return DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N1, N0); // fold (add x, 0) -> x if (N1C && N1C->isNullValue()) return N0; // fold (add Sym, c) -> Sym+c if (GlobalAddressSDNode *GA = dyn_cast(N0)) if (!LegalOperations && TLI.isOffsetFoldingLegal(GA) && N1C && GA->getOpcode() == ISD::GlobalAddress) return DAG.getGlobalAddress(GA->getGlobal(), N1C->getDebugLoc(), VT, GA->getOffset() + (uint64_t)N1C->getSExtValue()); // fold ((c1-A)+c2) -> (c1+c2)-A if (N1C && N0.getOpcode() == ISD::SUB) if (ConstantSDNode *N0C = dyn_cast(N0.getOperand(0))) return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, DAG.getConstant(N1C->getAPIntValue()+ N0C->getAPIntValue(), VT), N0.getOperand(1)); // reassociate add SDValue RADD = ReassociateOps(ISD::ADD, N->getDebugLoc(), N0, N1); if (RADD.getNode() != 0) return RADD; // fold ((0-A) + B) -> B-A if (N0.getOpcode() == ISD::SUB && isa(N0.getOperand(0)) && cast(N0.getOperand(0))->isNullValue()) return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N1, N0.getOperand(1)); // fold (A + (0-B)) -> A-B if (N1.getOpcode() == ISD::SUB && isa(N1.getOperand(0)) && cast(N1.getOperand(0))->isNullValue()) return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N0, N1.getOperand(1)); // fold (A+(B-A)) -> B if (N1.getOpcode() == ISD::SUB && N0 == N1.getOperand(1)) return N1.getOperand(0); // fold ((B-A)+A) -> B if (N0.getOpcode() == ISD::SUB && N1 == N0.getOperand(1)) return N0.getOperand(0); // fold (A+(B-(A+C))) to (B-C) if (N1.getOpcode() == ISD::SUB && N1.getOperand(1).getOpcode() == ISD::ADD && N0 == N1.getOperand(1).getOperand(0)) return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N1.getOperand(0), N1.getOperand(1).getOperand(1)); // fold (A+(B-(C+A))) to (B-C) if (N1.getOpcode() == ISD::SUB && N1.getOperand(1).getOpcode() == ISD::ADD && N0 == N1.getOperand(1).getOperand(1)) return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N1.getOperand(0), N1.getOperand(1).getOperand(0)); // fold (A+((B-A)+or-C)) to (B+or-C) if ((N1.getOpcode() == ISD::SUB || N1.getOpcode() == ISD::ADD) && N1.getOperand(0).getOpcode() == ISD::SUB && N0 == N1.getOperand(0).getOperand(1)) return DAG.getNode(N1.getOpcode(), N->getDebugLoc(), VT, N1.getOperand(0).getOperand(0), N1.getOperand(1)); // fold (A-B)+(C-D) to (A+C)-(B+D) when A or C is constant if (N0.getOpcode() == ISD::SUB && N1.getOpcode() == ISD::SUB) { SDValue N00 = N0.getOperand(0); SDValue N01 = N0.getOperand(1); SDValue N10 = N1.getOperand(0); SDValue N11 = N1.getOperand(1); if (isa(N00) || isa(N10)) return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, DAG.getNode(ISD::ADD, N0.getDebugLoc(), VT, N00, N10), DAG.getNode(ISD::ADD, N1.getDebugLoc(), VT, N01, N11)); } if (!VT.isVector() && SimplifyDemandedBits(SDValue(N, 0))) return SDValue(N, 0); // fold (a+b) -> (a|b) iff a and b share no bits. if (VT.isInteger() && !VT.isVector()) { APInt LHSZero, LHSOne; APInt RHSZero, RHSOne; APInt Mask = APInt::getAllOnesValue(VT.getScalarType().getSizeInBits()); DAG.ComputeMaskedBits(N0, Mask, LHSZero, LHSOne); if (LHSZero.getBoolValue()) { DAG.ComputeMaskedBits(N1, Mask, RHSZero, RHSOne); // If all possibly-set bits on the LHS are clear on the RHS, return an OR. // If all possibly-set bits on the RHS are clear on the LHS, return an OR. if ((RHSZero & (~LHSZero & Mask)) == (~LHSZero & Mask) || (LHSZero & (~RHSZero & Mask)) == (~RHSZero & Mask)) return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N0, N1); } } // fold (add (shl (add x, c1), c2), ) -> (add (add (shl x, c2), c1<hasOneUse()) { SDValue Result = combineShlAddConstant(N->getDebugLoc(), N0, N1, DAG); if (Result.getNode()) return Result; } if (N1.getOpcode() == ISD::SHL && N1.getNode()->hasOneUse()) { SDValue Result = combineShlAddConstant(N->getDebugLoc(), N1, N0, DAG); if (Result.getNode()) return Result; } // fold (add x, shl(0 - y, n)) -> sub(x, shl(y, n)) if (N1.getOpcode() == ISD::SHL && N1.getOperand(0).getOpcode() == ISD::SUB) if (ConstantSDNode *C = dyn_cast(N1.getOperand(0).getOperand(0))) if (C->getAPIntValue() == 0) return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N0, DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N1.getOperand(0).getOperand(1), N1.getOperand(1))); if (N0.getOpcode() == ISD::SHL && N0.getOperand(0).getOpcode() == ISD::SUB) if (ConstantSDNode *C = dyn_cast(N0.getOperand(0).getOperand(0))) if (C->getAPIntValue() == 0) return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N1, DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0.getOperand(0).getOperand(1), N0.getOperand(1))); if (N1.getOpcode() == ISD::AND) { SDValue AndOp0 = N1.getOperand(0); ConstantSDNode *AndOp1 = dyn_cast(N1->getOperand(1)); unsigned NumSignBits = DAG.ComputeNumSignBits(AndOp0); unsigned DestBits = VT.getScalarType().getSizeInBits(); // (add z, (and (sbbl x, x), 1)) -> (sub z, (sbbl x, x)) // and similar xforms where the inner op is either ~0 or 0. if (NumSignBits == DestBits && AndOp1 && AndOp1->isOne()) { DebugLoc DL = N->getDebugLoc(); return DAG.getNode(ISD::SUB, DL, VT, N->getOperand(0), AndOp0); } } // add (sext i1), X -> sub X, (zext i1) if (N0.getOpcode() == ISD::SIGN_EXTEND && N0.getOperand(0).getValueType() == MVT::i1 && !TLI.isOperationLegal(ISD::SIGN_EXTEND, MVT::i1)) { DebugLoc DL = N->getDebugLoc(); SDValue ZExt = DAG.getNode(ISD::ZERO_EXTEND, DL, VT, N0.getOperand(0)); return DAG.getNode(ISD::SUB, DL, VT, N1, ZExt); } // add (adde 0, 0, glue), X -> adde X, 0, glue if (N0->hasOneUse() && isCarryMaterialization(N0)) return DAG.getNode(ISD::ADDE, N->getDebugLoc(), DAG.getVTList(VT, MVT::Glue), N1, N0.getOperand(0), N0.getOperand(2)); // add X, (adde 0, 0, glue) -> adde X, 0, glue if (N1->hasOneUse() && isCarryMaterialization(N1)) return DAG.getNode(ISD::ADDE, N->getDebugLoc(), DAG.getVTList(VT, MVT::Glue), N0, N1.getOperand(0), N1.getOperand(2)); return SDValue(); } SDValue DAGCombiner::visitADDC(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); ConstantSDNode *N0C = dyn_cast(N0); ConstantSDNode *N1C = dyn_cast(N1); EVT VT = N0.getValueType(); // If the flag result is dead, turn this into an ADD. if (N->hasNUsesOfValue(0, 1)) return CombineTo(N, DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N1, N0), DAG.getNode(ISD::CARRY_FALSE, N->getDebugLoc(), MVT::Glue)); // canonicalize constant to RHS. if (N0C && !N1C) return DAG.getNode(ISD::ADDC, N->getDebugLoc(), N->getVTList(), N1, N0); // fold (addc x, 0) -> x + no carry out if (N1C && N1C->isNullValue()) return CombineTo(N, N0, DAG.getNode(ISD::CARRY_FALSE, N->getDebugLoc(), MVT::Glue)); // fold (addc a, b) -> (or a, b), CARRY_FALSE iff a and b share no bits. APInt LHSZero, LHSOne; APInt RHSZero, RHSOne; APInt Mask = APInt::getAllOnesValue(VT.getScalarType().getSizeInBits()); DAG.ComputeMaskedBits(N0, Mask, LHSZero, LHSOne); if (LHSZero.getBoolValue()) { DAG.ComputeMaskedBits(N1, Mask, RHSZero, RHSOne); // If all possibly-set bits on the LHS are clear on the RHS, return an OR. // If all possibly-set bits on the RHS are clear on the LHS, return an OR. if ((RHSZero & (~LHSZero & Mask)) == (~LHSZero & Mask) || (LHSZero & (~RHSZero & Mask)) == (~RHSZero & Mask)) return CombineTo(N, DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N0, N1), DAG.getNode(ISD::CARRY_FALSE, N->getDebugLoc(), MVT::Glue)); } // addc (adde 0, 0, glue), X -> adde X, 0, glue if (N0->hasOneUse() && isCarryMaterialization(N0)) return DAG.getNode(ISD::ADDE, N->getDebugLoc(), N->getVTList(), N1, DAG.getConstant(0, VT), N0.getOperand(2)); // addc X, (adde 0, 0, glue) -> adde X, 0, glue if (N1->hasOneUse() && isCarryMaterialization(N1)) return DAG.getNode(ISD::ADDE, N->getDebugLoc(), N->getVTList(), N0, DAG.getConstant(0, VT), N1.getOperand(2)); return SDValue(); } SDValue DAGCombiner::visitADDE(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); SDValue CarryIn = N->getOperand(2); ConstantSDNode *N0C = dyn_cast(N0); ConstantSDNode *N1C = dyn_cast(N1); // If both operands are null we know that carry out will always be false. if (N0C && N0C->isNullValue() && N0 == N1) DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), DAG.getNode(ISD::CARRY_FALSE, N->getDebugLoc(), MVT::Glue)); // canonicalize constant to RHS if (N0C && !N1C) return DAG.getNode(ISD::ADDE, N->getDebugLoc(), N->getVTList(), N1, N0, CarryIn); // fold (adde x, y, false) -> (addc x, y) if (CarryIn.getOpcode() == ISD::CARRY_FALSE) return DAG.getNode(ISD::ADDC, N->getDebugLoc(), N->getVTList(), N1, N0); return SDValue(); } // Since it may not be valid to emit a fold to zero for vector initializers // check if we can before folding. static SDValue tryFoldToZero(DebugLoc DL, const TargetLowering &TLI, EVT VT, SelectionDAG &DAG, bool LegalOperations) { if (!VT.isVector()) { return DAG.getConstant(0, VT); } else if (!LegalOperations || TLI.isOperationLegal(ISD::BUILD_VECTOR, VT)) { // Produce a vector of zeros. SDValue El = DAG.getConstant(0, VT.getVectorElementType()); std::vector Ops(VT.getVectorNumElements(), El); return DAG.getNode(ISD::BUILD_VECTOR, DL, VT, &Ops[0], Ops.size()); } return SDValue(); } SDValue DAGCombiner::visitSUB(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); ConstantSDNode *N0C = dyn_cast(N0.getNode()); ConstantSDNode *N1C = dyn_cast(N1.getNode()); EVT VT = N0.getValueType(); // fold vector ops if (VT.isVector()) { SDValue FoldedVOp = SimplifyVBinOp(N); if (FoldedVOp.getNode()) return FoldedVOp; } // fold (sub x, x) -> 0 // FIXME: Refactor this and xor and other similar operations together. if (N0 == N1) return tryFoldToZero(N->getDebugLoc(), TLI, VT, DAG, LegalOperations); // fold (sub c1, c2) -> c1-c2 if (N0C && N1C) return DAG.FoldConstantArithmetic(ISD::SUB, VT, N0C, N1C); // fold (sub x, c) -> (add x, -c) if (N1C) return DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N0, DAG.getConstant(-N1C->getAPIntValue(), VT)); // Canonicalize (sub -1, x) -> ~x, i.e. (xor x, -1) if (N0C && N0C->isAllOnesValue()) return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, N1, N0); // fold A-(A-B) -> B if (N1.getOpcode() == ISD::SUB && N0 == N1.getOperand(0)) return N1.getOperand(1); // fold (A+B)-A -> B if (N0.getOpcode() == ISD::ADD && N0.getOperand(0) == N1) return N0.getOperand(1); // fold (A+B)-B -> A if (N0.getOpcode() == ISD::ADD && N0.getOperand(1) == N1) return N0.getOperand(0); // fold ((A+(B+or-C))-B) -> A+or-C if (N0.getOpcode() == ISD::ADD && (N0.getOperand(1).getOpcode() == ISD::SUB || N0.getOperand(1).getOpcode() == ISD::ADD) && N0.getOperand(1).getOperand(0) == N1) return DAG.getNode(N0.getOperand(1).getOpcode(), N->getDebugLoc(), VT, N0.getOperand(0), N0.getOperand(1).getOperand(1)); // fold ((A+(C+B))-B) -> A+C if (N0.getOpcode() == ISD::ADD && N0.getOperand(1).getOpcode() == ISD::ADD && N0.getOperand(1).getOperand(1) == N1) return DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N0.getOperand(0), N0.getOperand(1).getOperand(0)); // fold ((A-(B-C))-C) -> A-B if (N0.getOpcode() == ISD::SUB && N0.getOperand(1).getOpcode() == ISD::SUB && N0.getOperand(1).getOperand(1) == N1) return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N0.getOperand(0), N0.getOperand(1).getOperand(0)); // If either operand of a sub is undef, the result is undef if (N0.getOpcode() == ISD::UNDEF) return N0; if (N1.getOpcode() == ISD::UNDEF) return N1; // If the relocation model supports it, consider symbol offsets. if (GlobalAddressSDNode *GA = dyn_cast(N0)) if (!LegalOperations && TLI.isOffsetFoldingLegal(GA)) { // fold (sub Sym, c) -> Sym-c if (N1C && GA->getOpcode() == ISD::GlobalAddress) return DAG.getGlobalAddress(GA->getGlobal(), N1C->getDebugLoc(), VT, GA->getOffset() - (uint64_t)N1C->getSExtValue()); // fold (sub Sym+c1, Sym+c2) -> c1-c2 if (GlobalAddressSDNode *GB = dyn_cast(N1)) if (GA->getGlobal() == GB->getGlobal()) return DAG.getConstant((uint64_t)GA->getOffset() - GB->getOffset(), VT); } return SDValue(); } SDValue DAGCombiner::visitMUL(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); ConstantSDNode *N0C = dyn_cast(N0); ConstantSDNode *N1C = dyn_cast(N1); EVT VT = N0.getValueType(); // fold vector ops if (VT.isVector()) { SDValue FoldedVOp = SimplifyVBinOp(N); if (FoldedVOp.getNode()) return FoldedVOp; } // fold (mul x, undef) -> 0 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF) return DAG.getConstant(0, VT); // fold (mul c1, c2) -> c1*c2 if (N0C && N1C) return DAG.FoldConstantArithmetic(ISD::MUL, VT, N0C, N1C); // canonicalize constant to RHS if (N0C && !N1C) return DAG.getNode(ISD::MUL, N->getDebugLoc(), VT, N1, N0); // fold (mul x, 0) -> 0 if (N1C && N1C->isNullValue()) return N1; // fold (mul x, -1) -> 0-x if (N1C && N1C->isAllOnesValue()) return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, DAG.getConstant(0, VT), N0); // fold (mul x, (1 << c)) -> x << c if (N1C && N1C->getAPIntValue().isPowerOf2()) return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0, DAG.getConstant(N1C->getAPIntValue().logBase2(), getShiftAmountTy(N0.getValueType()))); // fold (mul x, -(1 << c)) -> -(x << c) or (-x) << c if (N1C && (-N1C->getAPIntValue()).isPowerOf2()) { unsigned Log2Val = (-N1C->getAPIntValue()).logBase2(); // FIXME: If the input is something that is easily negated (e.g. a // single-use add), we should put the negate there. return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, DAG.getConstant(0, VT), DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0, DAG.getConstant(Log2Val, getShiftAmountTy(N0.getValueType())))); } // (mul (shl X, c1), c2) -> (mul X, c2 << c1) if (N1C && N0.getOpcode() == ISD::SHL && isa(N0.getOperand(1))) { SDValue C3 = DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N1, N0.getOperand(1)); AddToWorkList(C3.getNode()); return DAG.getNode(ISD::MUL, N->getDebugLoc(), VT, N0.getOperand(0), C3); } // Change (mul (shl X, C), Y) -> (shl (mul X, Y), C) when the shift has one // use. { SDValue Sh(0,0), Y(0,0); // Check for both (mul (shl X, C), Y) and (mul Y, (shl X, C)). if (N0.getOpcode() == ISD::SHL && isa(N0.getOperand(1)) && N0.getNode()->hasOneUse()) { Sh = N0; Y = N1; } else if (N1.getOpcode() == ISD::SHL && isa(N1.getOperand(1)) && N1.getNode()->hasOneUse()) { Sh = N1; Y = N0; } if (Sh.getNode()) { SDValue Mul = DAG.getNode(ISD::MUL, N->getDebugLoc(), VT, Sh.getOperand(0), Y); return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, Mul, Sh.getOperand(1)); } } // fold (mul (add x, c1), c2) -> (add (mul x, c2), c1*c2) if (N1C && N0.getOpcode() == ISD::ADD && N0.getNode()->hasOneUse() && isa(N0.getOperand(1))) return DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, DAG.getNode(ISD::MUL, N0.getDebugLoc(), VT, N0.getOperand(0), N1), DAG.getNode(ISD::MUL, N1.getDebugLoc(), VT, N0.getOperand(1), N1)); // reassociate mul SDValue RMUL = ReassociateOps(ISD::MUL, N->getDebugLoc(), N0, N1); if (RMUL.getNode() != 0) return RMUL; return SDValue(); } SDValue DAGCombiner::visitSDIV(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); ConstantSDNode *N0C = dyn_cast(N0.getNode()); ConstantSDNode *N1C = dyn_cast(N1.getNode()); EVT VT = N->getValueType(0); // fold vector ops if (VT.isVector()) { SDValue FoldedVOp = SimplifyVBinOp(N); if (FoldedVOp.getNode()) return FoldedVOp; } // fold (sdiv c1, c2) -> c1/c2 if (N0C && N1C && !N1C->isNullValue()) return DAG.FoldConstantArithmetic(ISD::SDIV, VT, N0C, N1C); // fold (sdiv X, 1) -> X if (N1C && N1C->getSExtValue() == 1LL) return N0; // fold (sdiv X, -1) -> 0-X if (N1C && N1C->isAllOnesValue()) return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, DAG.getConstant(0, VT), N0); // If we know the sign bits of both operands are zero, strength reduce to a // udiv instead. Handles (X&15) /s 4 -> X&15 >> 2 if (!VT.isVector()) { if (DAG.SignBitIsZero(N1) && DAG.SignBitIsZero(N0)) return DAG.getNode(ISD::UDIV, N->getDebugLoc(), N1.getValueType(), N0, N1); } // fold (sdiv X, pow2) -> simple ops after legalize if (N1C && !N1C->isNullValue() && !TLI.isIntDivCheap() && (isPowerOf2_64(N1C->getSExtValue()) || isPowerOf2_64(-N1C->getSExtValue()))) { // If dividing by powers of two is cheap, then don't perform the following // fold. if (TLI.isPow2DivCheap()) return SDValue(); int64_t pow2 = N1C->getSExtValue(); int64_t abs2 = pow2 > 0 ? pow2 : -pow2; unsigned lg2 = Log2_64(abs2); // Splat the sign bit into the register SDValue SGN = DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, N0, DAG.getConstant(VT.getSizeInBits()-1, getShiftAmountTy(N0.getValueType()))); AddToWorkList(SGN.getNode()); // Add (N0 < 0) ? abs2 - 1 : 0; SDValue SRL = DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, SGN, DAG.getConstant(VT.getSizeInBits() - lg2, getShiftAmountTy(SGN.getValueType()))); SDValue ADD = DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N0, SRL); AddToWorkList(SRL.getNode()); AddToWorkList(ADD.getNode()); // Divide by pow2 SDValue SRA = DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, ADD, DAG.getConstant(lg2, getShiftAmountTy(ADD.getValueType()))); // If we're dividing by a positive value, we're done. Otherwise, we must // negate the result. if (pow2 > 0) return SRA; AddToWorkList(SRA.getNode()); return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, DAG.getConstant(0, VT), SRA); } // if integer divide is expensive and we satisfy the requirements, emit an // alternate sequence. if (N1C && (N1C->getSExtValue() < -1 || N1C->getSExtValue() > 1) && !TLI.isIntDivCheap()) { SDValue Op = BuildSDIV(N); if (Op.getNode()) return Op; } // undef / X -> 0 if (N0.getOpcode() == ISD::UNDEF) return DAG.getConstant(0, VT); // X / undef -> undef if (N1.getOpcode() == ISD::UNDEF) return N1; return SDValue(); } SDValue DAGCombiner::visitUDIV(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); ConstantSDNode *N0C = dyn_cast(N0.getNode()); ConstantSDNode *N1C = dyn_cast(N1.getNode()); EVT VT = N->getValueType(0); // fold vector ops if (VT.isVector()) { SDValue FoldedVOp = SimplifyVBinOp(N); if (FoldedVOp.getNode()) return FoldedVOp; } // fold (udiv c1, c2) -> c1/c2 if (N0C && N1C && !N1C->isNullValue()) return DAG.FoldConstantArithmetic(ISD::UDIV, VT, N0C, N1C); // fold (udiv x, (1 << c)) -> x >>u c if (N1C && N1C->getAPIntValue().isPowerOf2()) return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0, DAG.getConstant(N1C->getAPIntValue().logBase2(), getShiftAmountTy(N0.getValueType()))); // fold (udiv x, (shl c, y)) -> x >>u (log2(c)+y) iff c is power of 2 if (N1.getOpcode() == ISD::SHL) { if (ConstantSDNode *SHC = dyn_cast(N1.getOperand(0))) { if (SHC->getAPIntValue().isPowerOf2()) { EVT ADDVT = N1.getOperand(1).getValueType(); SDValue Add = DAG.getNode(ISD::ADD, N->getDebugLoc(), ADDVT, N1.getOperand(1), DAG.getConstant(SHC->getAPIntValue() .logBase2(), ADDVT)); AddToWorkList(Add.getNode()); return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0, Add); } } } // fold (udiv x, c) -> alternate if (N1C && !N1C->isNullValue() && !TLI.isIntDivCheap()) { SDValue Op = BuildUDIV(N); if (Op.getNode()) return Op; } // undef / X -> 0 if (N0.getOpcode() == ISD::UNDEF) return DAG.getConstant(0, VT); // X / undef -> undef if (N1.getOpcode() == ISD::UNDEF) return N1; return SDValue(); } SDValue DAGCombiner::visitSREM(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); ConstantSDNode *N0C = dyn_cast(N0); ConstantSDNode *N1C = dyn_cast(N1); EVT VT = N->getValueType(0); // fold (srem c1, c2) -> c1%c2 if (N0C && N1C && !N1C->isNullValue()) return DAG.FoldConstantArithmetic(ISD::SREM, VT, N0C, N1C); // If we know the sign bits of both operands are zero, strength reduce to a // urem instead. Handles (X & 0x0FFFFFFF) %s 16 -> X&15 if (!VT.isVector()) { if (DAG.SignBitIsZero(N1) && DAG.SignBitIsZero(N0)) return DAG.getNode(ISD::UREM, N->getDebugLoc(), VT, N0, N1); } // If X/C can be simplified by the division-by-constant logic, lower // X%C to the equivalent of X-X/C*C. if (N1C && !N1C->isNullValue()) { SDValue Div = DAG.getNode(ISD::SDIV, N->getDebugLoc(), VT, N0, N1); AddToWorkList(Div.getNode()); SDValue OptimizedDiv = combine(Div.getNode()); if (OptimizedDiv.getNode() && OptimizedDiv.getNode() != Div.getNode()) { SDValue Mul = DAG.getNode(ISD::MUL, N->getDebugLoc(), VT, OptimizedDiv, N1); SDValue Sub = DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N0, Mul); AddToWorkList(Mul.getNode()); return Sub; } } // undef % X -> 0 if (N0.getOpcode() == ISD::UNDEF) return DAG.getConstant(0, VT); // X % undef -> undef if (N1.getOpcode() == ISD::UNDEF) return N1; return SDValue(); } SDValue DAGCombiner::visitUREM(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); ConstantSDNode *N0C = dyn_cast(N0); ConstantSDNode *N1C = dyn_cast(N1); EVT VT = N->getValueType(0); // fold (urem c1, c2) -> c1%c2 if (N0C && N1C && !N1C->isNullValue()) return DAG.FoldConstantArithmetic(ISD::UREM, VT, N0C, N1C); // fold (urem x, pow2) -> (and x, pow2-1) if (N1C && !N1C->isNullValue() && N1C->getAPIntValue().isPowerOf2()) return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0, DAG.getConstant(N1C->getAPIntValue()-1,VT)); // fold (urem x, (shl pow2, y)) -> (and x, (add (shl pow2, y), -1)) if (N1.getOpcode() == ISD::SHL) { if (ConstantSDNode *SHC = dyn_cast(N1.getOperand(0))) { if (SHC->getAPIntValue().isPowerOf2()) { SDValue Add = DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N1, DAG.getConstant(APInt::getAllOnesValue(VT.getSizeInBits()), VT)); AddToWorkList(Add.getNode()); return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0, Add); } } } // If X/C can be simplified by the division-by-constant logic, lower // X%C to the equivalent of X-X/C*C. if (N1C && !N1C->isNullValue()) { SDValue Div = DAG.getNode(ISD::UDIV, N->getDebugLoc(), VT, N0, N1); AddToWorkList(Div.getNode()); SDValue OptimizedDiv = combine(Div.getNode()); if (OptimizedDiv.getNode() && OptimizedDiv.getNode() != Div.getNode()) { SDValue Mul = DAG.getNode(ISD::MUL, N->getDebugLoc(), VT, OptimizedDiv, N1); SDValue Sub = DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N0, Mul); AddToWorkList(Mul.getNode()); return Sub; } } // undef % X -> 0 if (N0.getOpcode() == ISD::UNDEF) return DAG.getConstant(0, VT); // X % undef -> undef if (N1.getOpcode() == ISD::UNDEF) return N1; return SDValue(); } SDValue DAGCombiner::visitMULHS(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); ConstantSDNode *N1C = dyn_cast(N1); EVT VT = N->getValueType(0); DebugLoc DL = N->getDebugLoc(); // fold (mulhs x, 0) -> 0 if (N1C && N1C->isNullValue()) return N1; // fold (mulhs x, 1) -> (sra x, size(x)-1) if (N1C && N1C->getAPIntValue() == 1) return DAG.getNode(ISD::SRA, N->getDebugLoc(), N0.getValueType(), N0, DAG.getConstant(N0.getValueType().getSizeInBits() - 1, getShiftAmountTy(N0.getValueType()))); // fold (mulhs x, undef) -> 0 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF) return DAG.getConstant(0, VT); // If the type twice as wide is legal, transform the mulhs to a wider multiply // plus a shift. if (VT.isSimple() && !VT.isVector()) { MVT Simple = VT.getSimpleVT(); unsigned SimpleSize = Simple.getSizeInBits(); EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), SimpleSize*2); if (TLI.isOperationLegal(ISD::MUL, NewVT)) { N0 = DAG.getNode(ISD::SIGN_EXTEND, DL, NewVT, N0); N1 = DAG.getNode(ISD::SIGN_EXTEND, DL, NewVT, N1); N1 = DAG.getNode(ISD::MUL, DL, NewVT, N0, N1); N1 = DAG.getNode(ISD::SRL, DL, NewVT, N1, DAG.getConstant(SimpleSize, getShiftAmountTy(N1.getValueType()))); return DAG.getNode(ISD::TRUNCATE, DL, VT, N1); } } return SDValue(); } SDValue DAGCombiner::visitMULHU(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); ConstantSDNode *N1C = dyn_cast(N1); EVT VT = N->getValueType(0); DebugLoc DL = N->getDebugLoc(); // fold (mulhu x, 0) -> 0 if (N1C && N1C->isNullValue()) return N1; // fold (mulhu x, 1) -> 0 if (N1C && N1C->getAPIntValue() == 1) return DAG.getConstant(0, N0.getValueType()); // fold (mulhu x, undef) -> 0 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF) return DAG.getConstant(0, VT); // If the type twice as wide is legal, transform the mulhu to a wider multiply // plus a shift. if (VT.isSimple() && !VT.isVector()) { MVT Simple = VT.getSimpleVT(); unsigned SimpleSize = Simple.getSizeInBits(); EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), SimpleSize*2); if (TLI.isOperationLegal(ISD::MUL, NewVT)) { N0 = DAG.getNode(ISD::ZERO_EXTEND, DL, NewVT, N0); N1 = DAG.getNode(ISD::ZERO_EXTEND, DL, NewVT, N1); N1 = DAG.getNode(ISD::MUL, DL, NewVT, N0, N1); N1 = DAG.getNode(ISD::SRL, DL, NewVT, N1, DAG.getConstant(SimpleSize, getShiftAmountTy(N1.getValueType()))); return DAG.getNode(ISD::TRUNCATE, DL, VT, N1); } } return SDValue(); } /// SimplifyNodeWithTwoResults - Perform optimizations common to nodes that /// compute two values. LoOp and HiOp give the opcodes for the two computations /// that are being performed. Return true if a simplification was made. /// SDValue DAGCombiner::SimplifyNodeWithTwoResults(SDNode *N, unsigned LoOp, unsigned HiOp) { // If the high half is not needed, just compute the low half. bool HiExists = N->hasAnyUseOfValue(1); if (!HiExists && (!LegalOperations || TLI.isOperationLegal(LoOp, N->getValueType(0)))) { SDValue Res = DAG.getNode(LoOp, N->getDebugLoc(), N->getValueType(0), N->op_begin(), N->getNumOperands()); return CombineTo(N, Res, Res); } // If the low half is not needed, just compute the high half. bool LoExists = N->hasAnyUseOfValue(0); if (!LoExists && (!LegalOperations || TLI.isOperationLegal(HiOp, N->getValueType(1)))) { SDValue Res = DAG.getNode(HiOp, N->getDebugLoc(), N->getValueType(1), N->op_begin(), N->getNumOperands()); return CombineTo(N, Res, Res); } // If both halves are used, return as it is. if (LoExists && HiExists) return SDValue(); // If the two computed results can be simplified separately, separate them. if (LoExists) { SDValue Lo = DAG.getNode(LoOp, N->getDebugLoc(), N->getValueType(0), N->op_begin(), N->getNumOperands()); AddToWorkList(Lo.getNode()); SDValue LoOpt = combine(Lo.getNode()); if (LoOpt.getNode() && LoOpt.getNode() != Lo.getNode() && (!LegalOperations || TLI.isOperationLegal(LoOpt.getOpcode(), LoOpt.getValueType()))) return CombineTo(N, LoOpt, LoOpt); } if (HiExists) { SDValue Hi = DAG.getNode(HiOp, N->getDebugLoc(), N->getValueType(1), N->op_begin(), N->getNumOperands()); AddToWorkList(Hi.getNode()); SDValue HiOpt = combine(Hi.getNode()); if (HiOpt.getNode() && HiOpt != Hi && (!LegalOperations || TLI.isOperationLegal(HiOpt.getOpcode(), HiOpt.getValueType()))) return CombineTo(N, HiOpt, HiOpt); } return SDValue(); } SDValue DAGCombiner::visitSMUL_LOHI(SDNode *N) { SDValue Res = SimplifyNodeWithTwoResults(N, ISD::MUL, ISD::MULHS); if (Res.getNode()) return Res; EVT VT = N->getValueType(0); DebugLoc DL = N->getDebugLoc(); // If the type twice as wide is legal, transform the mulhu to a wider multiply // plus a shift. if (VT.isSimple() && !VT.isVector()) { MVT Simple = VT.getSimpleVT(); unsigned SimpleSize = Simple.getSizeInBits(); EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), SimpleSize*2); if (TLI.isOperationLegal(ISD::MUL, NewVT)) { SDValue Lo = DAG.getNode(ISD::SIGN_EXTEND, DL, NewVT, N->getOperand(0)); SDValue Hi = DAG.getNode(ISD::SIGN_EXTEND, DL, NewVT, N->getOperand(1)); Lo = DAG.getNode(ISD::MUL, DL, NewVT, Lo, Hi); // Compute the high part as N1. Hi = DAG.getNode(ISD::SRL, DL, NewVT, Lo, DAG.getConstant(SimpleSize, getShiftAmountTy(Lo.getValueType()))); Hi = DAG.getNode(ISD::TRUNCATE, DL, VT, Hi); // Compute the low part as N0. Lo = DAG.getNode(ISD::TRUNCATE, DL, VT, Lo); return CombineTo(N, Lo, Hi); } } return SDValue(); } SDValue DAGCombiner::visitUMUL_LOHI(SDNode *N) { SDValue Res = SimplifyNodeWithTwoResults(N, ISD::MUL, ISD::MULHU); if (Res.getNode()) return Res; EVT VT = N->getValueType(0); DebugLoc DL = N->getDebugLoc(); // If the type twice as wide is legal, transform the mulhu to a wider multiply // plus a shift. if (VT.isSimple() && !VT.isVector()) { MVT Simple = VT.getSimpleVT(); unsigned SimpleSize = Simple.getSizeInBits(); EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), SimpleSize*2); if (TLI.isOperationLegal(ISD::MUL, NewVT)) { SDValue Lo = DAG.getNode(ISD::ZERO_EXTEND, DL, NewVT, N->getOperand(0)); SDValue Hi = DAG.getNode(ISD::ZERO_EXTEND, DL, NewVT, N->getOperand(1)); Lo = DAG.getNode(ISD::MUL, DL, NewVT, Lo, Hi); // Compute the high part as N1. Hi = DAG.getNode(ISD::SRL, DL, NewVT, Lo, DAG.getConstant(SimpleSize, getShiftAmountTy(Lo.getValueType()))); Hi = DAG.getNode(ISD::TRUNCATE, DL, VT, Hi); // Compute the low part as N0. Lo = DAG.getNode(ISD::TRUNCATE, DL, VT, Lo); return CombineTo(N, Lo, Hi); } } return SDValue(); } SDValue DAGCombiner::visitSDIVREM(SDNode *N) { SDValue Res = SimplifyNodeWithTwoResults(N, ISD::SDIV, ISD::SREM); if (Res.getNode()) return Res; return SDValue(); } SDValue DAGCombiner::visitUDIVREM(SDNode *N) { SDValue Res = SimplifyNodeWithTwoResults(N, ISD::UDIV, ISD::UREM); if (Res.getNode()) return Res; return SDValue(); } /// SimplifyBinOpWithSameOpcodeHands - If this is a binary operator with /// two operands of the same opcode, try to simplify it. SDValue DAGCombiner::SimplifyBinOpWithSameOpcodeHands(SDNode *N) { SDValue N0 = N->getOperand(0), N1 = N->getOperand(1); EVT VT = N0.getValueType(); assert(N0.getOpcode() == N1.getOpcode() && "Bad input!"); // Bail early if none of these transforms apply. if (N0.getNode()->getNumOperands() == 0) return SDValue(); // For each of OP in AND/OR/XOR: // fold (OP (zext x), (zext y)) -> (zext (OP x, y)) // fold (OP (sext x), (sext y)) -> (sext (OP x, y)) // fold (OP (aext x), (aext y)) -> (aext (OP x, y)) // fold (OP (trunc x), (trunc y)) -> (trunc (OP x, y)) (if trunc isn't free) // // do not sink logical op inside of a vector extend, since it may combine // into a vsetcc. EVT Op0VT = N0.getOperand(0).getValueType(); if ((N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::SIGN_EXTEND || // Avoid infinite looping with PromoteIntBinOp. (N0.getOpcode() == ISD::ANY_EXTEND && (!LegalTypes || TLI.isTypeDesirableForOp(N->getOpcode(), Op0VT))) || (N0.getOpcode() == ISD::TRUNCATE && (!TLI.isZExtFree(VT, Op0VT) || !TLI.isTruncateFree(Op0VT, VT)) && TLI.isTypeLegal(Op0VT))) && !VT.isVector() && Op0VT == N1.getOperand(0).getValueType() && (!LegalOperations || TLI.isOperationLegal(N->getOpcode(), Op0VT))) { SDValue ORNode = DAG.getNode(N->getOpcode(), N0.getDebugLoc(), N0.getOperand(0).getValueType(), N0.getOperand(0), N1.getOperand(0)); AddToWorkList(ORNode.getNode()); return DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT, ORNode); } // For each of OP in SHL/SRL/SRA/AND... // fold (and (OP x, z), (OP y, z)) -> (OP (and x, y), z) // fold (or (OP x, z), (OP y, z)) -> (OP (or x, y), z) // fold (xor (OP x, z), (OP y, z)) -> (OP (xor x, y), z) if ((N0.getOpcode() == ISD::SHL || N0.getOpcode() == ISD::SRL || N0.getOpcode() == ISD::SRA || N0.getOpcode() == ISD::AND) && N0.getOperand(1) == N1.getOperand(1)) { SDValue ORNode = DAG.getNode(N->getOpcode(), N0.getDebugLoc(), N0.getOperand(0).getValueType(), N0.getOperand(0), N1.getOperand(0)); AddToWorkList(ORNode.getNode()); return DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT, ORNode, N0.getOperand(1)); } return SDValue(); } SDValue DAGCombiner::visitAND(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); SDValue LL, LR, RL, RR, CC0, CC1; ConstantSDNode *N0C = dyn_cast(N0); ConstantSDNode *N1C = dyn_cast(N1); EVT VT = N1.getValueType(); unsigned BitWidth = VT.getScalarType().getSizeInBits(); // fold vector ops if (VT.isVector()) { SDValue FoldedVOp = SimplifyVBinOp(N); if (FoldedVOp.getNode()) return FoldedVOp; } // fold (and x, undef) -> 0 if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF) return DAG.getConstant(0, VT); // fold (and c1, c2) -> c1&c2 if (N0C && N1C) return DAG.FoldConstantArithmetic(ISD::AND, VT, N0C, N1C); // canonicalize constant to RHS if (N0C && !N1C) return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N1, N0); // fold (and x, -1) -> x if (N1C && N1C->isAllOnesValue()) return N0; // if (and x, c) is known to be zero, return 0 if (N1C && DAG.MaskedValueIsZero(SDValue(N, 0), APInt::getAllOnesValue(BitWidth))) return DAG.getConstant(0, VT); // reassociate and SDValue RAND = ReassociateOps(ISD::AND, N->getDebugLoc(), N0, N1); if (RAND.getNode() != 0) return RAND; // fold (and (or x, C), D) -> D if (C & D) == D if (N1C && N0.getOpcode() == ISD::OR) if (ConstantSDNode *ORI = dyn_cast(N0.getOperand(1))) if ((ORI->getAPIntValue() & N1C->getAPIntValue()) == N1C->getAPIntValue()) return N1; // fold (and (any_ext V), c) -> (zero_ext V) if 'and' only clears top bits. if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) { SDValue N0Op0 = N0.getOperand(0); APInt Mask = ~N1C->getAPIntValue(); Mask = Mask.trunc(N0Op0.getValueSizeInBits()); if (DAG.MaskedValueIsZero(N0Op0, Mask)) { SDValue Zext = DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), N0.getValueType(), N0Op0); // Replace uses of the AND with uses of the Zero extend node. CombineTo(N, Zext); // We actually want to replace all uses of the any_extend with the // zero_extend, to avoid duplicating things. This will later cause this // AND to be folded. CombineTo(N0.getNode(), Zext); return SDValue(N, 0); // Return N so it doesn't get rechecked! } } // fold (and (setcc x), (setcc y)) -> (setcc (and x, y)) if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){ ISD::CondCode Op0 = cast(CC0)->get(); ISD::CondCode Op1 = cast(CC1)->get(); if (LR == RR && isa(LR) && Op0 == Op1 && LL.getValueType().isInteger()) { // fold (and (seteq X, 0), (seteq Y, 0)) -> (seteq (or X, Y), 0) if (cast(LR)->isNullValue() && Op1 == ISD::SETEQ) { SDValue ORNode = DAG.getNode(ISD::OR, N0.getDebugLoc(), LR.getValueType(), LL, RL); AddToWorkList(ORNode.getNode()); return DAG.getSetCC(N->getDebugLoc(), VT, ORNode, LR, Op1); } // fold (and (seteq X, -1), (seteq Y, -1)) -> (seteq (and X, Y), -1) if (cast(LR)->isAllOnesValue() && Op1 == ISD::SETEQ) { SDValue ANDNode = DAG.getNode(ISD::AND, N0.getDebugLoc(), LR.getValueType(), LL, RL); AddToWorkList(ANDNode.getNode()); return DAG.getSetCC(N->getDebugLoc(), VT, ANDNode, LR, Op1); } // fold (and (setgt X, -1), (setgt Y, -1)) -> (setgt (or X, Y), -1) if (cast(LR)->isAllOnesValue() && Op1 == ISD::SETGT) { SDValue ORNode = DAG.getNode(ISD::OR, N0.getDebugLoc(), LR.getValueType(), LL, RL); AddToWorkList(ORNode.getNode()); return DAG.getSetCC(N->getDebugLoc(), VT, ORNode, LR, Op1); } } // canonicalize equivalent to ll == rl if (LL == RR && LR == RL) { Op1 = ISD::getSetCCSwappedOperands(Op1); std::swap(RL, RR); } if (LL == RL && LR == RR) { bool isInteger = LL.getValueType().isInteger(); ISD::CondCode Result = ISD::getSetCCAndOperation(Op0, Op1, isInteger); if (Result != ISD::SETCC_INVALID && (!LegalOperations || TLI.isCondCodeLegal(Result, LL.getValueType()))) return DAG.getSetCC(N->getDebugLoc(), N0.getValueType(), LL, LR, Result); } } // Simplify: (and (op x...), (op y...)) -> (op (and x, y)) if (N0.getOpcode() == N1.getOpcode()) { SDValue Tmp = SimplifyBinOpWithSameOpcodeHands(N); if (Tmp.getNode()) return Tmp; } // fold (and (sign_extend_inreg x, i16 to i32), 1) -> (and x, 1) // fold (and (sra)) -> (and (srl)) when possible. if (!VT.isVector() && SimplifyDemandedBits(SDValue(N, 0))) return SDValue(N, 0); // fold (zext_inreg (extload x)) -> (zextload x) if (ISD::isEXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode())) { LoadSDNode *LN0 = cast(N0); EVT MemVT = LN0->getMemoryVT(); // If we zero all the possible extended bits, then we can turn this into // a zextload if we are running before legalize or the operation is legal. unsigned BitWidth = N1.getValueType().getScalarType().getSizeInBits(); if (DAG.MaskedValueIsZero(N1, APInt::getHighBitsSet(BitWidth, BitWidth - MemVT.getScalarType().getSizeInBits())) && ((!LegalOperations && !LN0->isVolatile()) || TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT))) { SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, N0.getDebugLoc(), VT, LN0->getChain(), LN0->getBasePtr(), LN0->getPointerInfo(), MemVT, LN0->isVolatile(), LN0->isNonTemporal(), LN0->getAlignment()); AddToWorkList(N); CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1)); return SDValue(N, 0); // Return N so it doesn't get rechecked! } } // fold (zext_inreg (sextload x)) -> (zextload x) iff load has one use if (ISD::isSEXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) && N0.hasOneUse()) { LoadSDNode *LN0 = cast(N0); EVT MemVT = LN0->getMemoryVT(); // If we zero all the possible extended bits, then we can turn this into // a zextload if we are running before legalize or the operation is legal. unsigned BitWidth = N1.getValueType().getScalarType().getSizeInBits(); if (DAG.MaskedValueIsZero(N1, APInt::getHighBitsSet(BitWidth, BitWidth - MemVT.getScalarType().getSizeInBits())) && ((!LegalOperations && !LN0->isVolatile()) || TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT))) { SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, N0.getDebugLoc(), VT, LN0->getChain(), LN0->getBasePtr(), LN0->getPointerInfo(), MemVT, LN0->isVolatile(), LN0->isNonTemporal(), LN0->getAlignment()); AddToWorkList(N); CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1)); return SDValue(N, 0); // Return N so it doesn't get rechecked! } } // fold (and (load x), 255) -> (zextload x, i8) // fold (and (extload x, i16), 255) -> (zextload x, i8) // fold (and (any_ext (extload x, i16)), 255) -> (zextload x, i8) if (N1C && (N0.getOpcode() == ISD::LOAD || (N0.getOpcode() == ISD::ANY_EXTEND && N0.getOperand(0).getOpcode() == ISD::LOAD))) { bool HasAnyExt = N0.getOpcode() == ISD::ANY_EXTEND; LoadSDNode *LN0 = HasAnyExt ? cast(N0.getOperand(0)) : cast(N0); if (LN0->getExtensionType() != ISD::SEXTLOAD && LN0->isUnindexed() && N0.hasOneUse() && LN0->hasOneUse()) { uint32_t ActiveBits = N1C->getAPIntValue().getActiveBits(); if (ActiveBits > 0 && APIntOps::isMask(ActiveBits, N1C->getAPIntValue())){ EVT ExtVT = EVT::getIntegerVT(*DAG.getContext(), ActiveBits); EVT LoadedVT = LN0->getMemoryVT(); if (ExtVT == LoadedVT && (!LegalOperations || TLI.isLoadExtLegal(ISD::ZEXTLOAD, ExtVT))) { EVT LoadResultTy = HasAnyExt ? LN0->getValueType(0) : VT; SDValue NewLoad = DAG.getExtLoad(ISD::ZEXTLOAD, LN0->getDebugLoc(), LoadResultTy, LN0->getChain(), LN0->getBasePtr(), LN0->getPointerInfo(), ExtVT, LN0->isVolatile(), LN0->isNonTemporal(), LN0->getAlignment()); AddToWorkList(N); CombineTo(LN0, NewLoad, NewLoad.getValue(1)); return SDValue(N, 0); // Return N so it doesn't get rechecked! } // Do not change the width of a volatile load. // Do not generate loads of non-round integer types since these can // be expensive (and would be wrong if the type is not byte sized). if (!LN0->isVolatile() && LoadedVT.bitsGT(ExtVT) && ExtVT.isRound() && (!LegalOperations || TLI.isLoadExtLegal(ISD::ZEXTLOAD, ExtVT))) { EVT PtrType = LN0->getOperand(1).getValueType(); unsigned Alignment = LN0->getAlignment(); SDValue NewPtr = LN0->getBasePtr(); // For big endian targets, we need to add an offset to the pointer // to load the correct bytes. For little endian systems, we merely // need to read fewer bytes from the same pointer. if (TLI.isBigEndian()) { unsigned LVTStoreBytes = LoadedVT.getStoreSize(); unsigned EVTStoreBytes = ExtVT.getStoreSize(); unsigned PtrOff = LVTStoreBytes - EVTStoreBytes; NewPtr = DAG.getNode(ISD::ADD, LN0->getDebugLoc(), PtrType, NewPtr, DAG.getConstant(PtrOff, PtrType)); Alignment = MinAlign(Alignment, PtrOff); } AddToWorkList(NewPtr.getNode()); EVT LoadResultTy = HasAnyExt ? LN0->getValueType(0) : VT; SDValue Load = DAG.getExtLoad(ISD::ZEXTLOAD, LN0->getDebugLoc(), LoadResultTy, LN0->getChain(), NewPtr, LN0->getPointerInfo(), ExtVT, LN0->isVolatile(), LN0->isNonTemporal(), Alignment); AddToWorkList(N); CombineTo(LN0, Load, Load.getValue(1)); return SDValue(N, 0); // Return N so it doesn't get rechecked! } } } } return SDValue(); } SDValue DAGCombiner::visitOR(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); SDValue LL, LR, RL, RR, CC0, CC1; ConstantSDNode *N0C = dyn_cast(N0); ConstantSDNode *N1C = dyn_cast(N1); EVT VT = N1.getValueType(); // fold vector ops if (VT.isVector()) { SDValue FoldedVOp = SimplifyVBinOp(N); if (FoldedVOp.getNode()) return FoldedVOp; } // fold (or x, undef) -> -1 if (!LegalOperations && (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF)) { EVT EltVT = VT.isVector() ? VT.getVectorElementType() : VT; return DAG.getConstant(APInt::getAllOnesValue(EltVT.getSizeInBits()), VT); } // fold (or c1, c2) -> c1|c2 if (N0C && N1C) return DAG.FoldConstantArithmetic(ISD::OR, VT, N0C, N1C); // canonicalize constant to RHS if (N0C && !N1C) return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N1, N0); // fold (or x, 0) -> x if (N1C && N1C->isNullValue()) return N0; // fold (or x, -1) -> -1 if (N1C && N1C->isAllOnesValue()) return N1; // fold (or x, c) -> c iff (x & ~c) == 0 if (N1C && DAG.MaskedValueIsZero(N0, ~N1C->getAPIntValue())) return N1; // reassociate or SDValue ROR = ReassociateOps(ISD::OR, N->getDebugLoc(), N0, N1); if (ROR.getNode() != 0) return ROR; // Canonicalize (or (and X, c1), c2) -> (and (or X, c2), c1|c2) // iff (c1 & c2) == 0. if (N1C && N0.getOpcode() == ISD::AND && N0.getNode()->hasOneUse() && isa(N0.getOperand(1))) { ConstantSDNode *C1 = cast(N0.getOperand(1)); if ((C1->getAPIntValue() & N1C->getAPIntValue()) != 0) return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, DAG.getNode(ISD::OR, N0.getDebugLoc(), VT, N0.getOperand(0), N1), DAG.FoldConstantArithmetic(ISD::OR, VT, N1C, C1)); } // fold (or (setcc x), (setcc y)) -> (setcc (or x, y)) if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){ ISD::CondCode Op0 = cast(CC0)->get(); ISD::CondCode Op1 = cast(CC1)->get(); if (LR == RR && isa(LR) && Op0 == Op1 && LL.getValueType().isInteger()) { // fold (or (setne X, 0), (setne Y, 0)) -> (setne (or X, Y), 0) // fold (or (setlt X, 0), (setlt Y, 0)) -> (setne (or X, Y), 0) if (cast(LR)->isNullValue() && (Op1 == ISD::SETNE || Op1 == ISD::SETLT)) { SDValue ORNode = DAG.getNode(ISD::OR, LR.getDebugLoc(), LR.getValueType(), LL, RL); AddToWorkList(ORNode.getNode()); return DAG.getSetCC(N->getDebugLoc(), VT, ORNode, LR, Op1); } // fold (or (setne X, -1), (setne Y, -1)) -> (setne (and X, Y), -1) // fold (or (setgt X, -1), (setgt Y -1)) -> (setgt (and X, Y), -1) if (cast(LR)->isAllOnesValue() && (Op1 == ISD::SETNE || Op1 == ISD::SETGT)) { SDValue ANDNode = DAG.getNode(ISD::AND, LR.getDebugLoc(), LR.getValueType(), LL, RL); AddToWorkList(ANDNode.getNode()); return DAG.getSetCC(N->getDebugLoc(), VT, ANDNode, LR, Op1); } } // canonicalize equivalent to ll == rl if (LL == RR && LR == RL) { Op1 = ISD::getSetCCSwappedOperands(Op1); std::swap(RL, RR); } if (LL == RL && LR == RR) { bool isInteger = LL.getValueType().isInteger(); ISD::CondCode Result = ISD::getSetCCOrOperation(Op0, Op1, isInteger); if (Result != ISD::SETCC_INVALID && (!LegalOperations || TLI.isCondCodeLegal(Result, LL.getValueType()))) return DAG.getSetCC(N->getDebugLoc(), N0.getValueType(), LL, LR, Result); } } // Simplify: (or (op x...), (op y...)) -> (op (or x, y)) if (N0.getOpcode() == N1.getOpcode()) { SDValue Tmp = SimplifyBinOpWithSameOpcodeHands(N); if (Tmp.getNode()) return Tmp; } // (or (and X, C1), (and Y, C2)) -> (and (or X, Y), C3) if possible. if (N0.getOpcode() == ISD::AND && N1.getOpcode() == ISD::AND && N0.getOperand(1).getOpcode() == ISD::Constant && N1.getOperand(1).getOpcode() == ISD::Constant && // Don't increase # computations. (N0.getNode()->hasOneUse() || N1.getNode()->hasOneUse())) { // We can only do this xform if we know that bits from X that are set in C2 // but not in C1 are already zero. Likewise for Y. const APInt &LHSMask = cast(N0.getOperand(1))->getAPIntValue(); const APInt &RHSMask = cast(N1.getOperand(1))->getAPIntValue(); if (DAG.MaskedValueIsZero(N0.getOperand(0), RHSMask&~LHSMask) && DAG.MaskedValueIsZero(N1.getOperand(0), LHSMask&~RHSMask)) { SDValue X = DAG.getNode(ISD::OR, N0.getDebugLoc(), VT, N0.getOperand(0), N1.getOperand(0)); return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, X, DAG.getConstant(LHSMask | RHSMask, VT)); } } // See if this is some rotate idiom. if (SDNode *Rot = MatchRotate(N0, N1, N->getDebugLoc())) return SDValue(Rot, 0); // Simplify the operands using demanded-bits information. if (!VT.isVector() && SimplifyDemandedBits(SDValue(N, 0))) return SDValue(N, 0); return SDValue(); } /// MatchRotateHalf - Match "(X shl/srl V1) & V2" where V2 may not be present. static bool MatchRotateHalf(SDValue Op, SDValue &Shift, SDValue &Mask) { if (Op.getOpcode() == ISD::AND) { if (isa(Op.getOperand(1))) { Mask = Op.getOperand(1); Op = Op.getOperand(0); } else { return false; } } if (Op.getOpcode() == ISD::SRL || Op.getOpcode() == ISD::SHL) { Shift = Op; return true; } return false; } // MatchRotate - Handle an 'or' of two operands. If this is one of the many // idioms for rotate, and if the target supports rotation instructions, generate // a rot[lr]. SDNode *DAGCombiner::MatchRotate(SDValue LHS, SDValue RHS, DebugLoc DL) { // Must be a legal type. Expanded 'n promoted things won't work with rotates. EVT VT = LHS.getValueType(); if (!TLI.isTypeLegal(VT)) return 0; // The target must have at least one rotate flavor. bool HasROTL = TLI.isOperationLegalOrCustom(ISD::ROTL, VT); bool HasROTR = TLI.isOperationLegalOrCustom(ISD::ROTR, VT); if (!HasROTL && !HasROTR) return 0; // Match "(X shl/srl V1) & V2" where V2 may not be present. SDValue LHSShift; // The shift. SDValue LHSMask; // AND value if any. if (!MatchRotateHalf(LHS, LHSShift, LHSMask)) return 0; // Not part of a rotate. SDValue RHSShift; // The shift. SDValue RHSMask; // AND value if any. if (!MatchRotateHalf(RHS, RHSShift, RHSMask)) return 0; // Not part of a rotate. if (LHSShift.getOperand(0) != RHSShift.getOperand(0)) return 0; // Not shifting the same value. if (LHSShift.getOpcode() == RHSShift.getOpcode()) return 0; // Shifts must disagree. // Canonicalize shl to left side in a shl/srl pair. if (RHSShift.getOpcode() == ISD::SHL) { std::swap(LHS, RHS); std::swap(LHSShift, RHSShift); std::swap(LHSMask , RHSMask ); } unsigned OpSizeInBits = VT.getSizeInBits(); SDValue LHSShiftArg = LHSShift.getOperand(0); SDValue LHSShiftAmt = LHSShift.getOperand(1); SDValue RHSShiftAmt = RHSShift.getOperand(1); // fold (or (shl x, C1), (srl x, C2)) -> (rotl x, C1) // fold (or (shl x, C1), (srl x, C2)) -> (rotr x, C2) if (LHSShiftAmt.getOpcode() == ISD::Constant && RHSShiftAmt.getOpcode() == ISD::Constant) { uint64_t LShVal = cast(LHSShiftAmt)->getZExtValue(); uint64_t RShVal = cast(RHSShiftAmt)->getZExtValue(); if ((LShVal + RShVal) != OpSizeInBits) return 0; SDValue Rot; if (HasROTL) Rot = DAG.getNode(ISD::ROTL, DL, VT, LHSShiftArg, LHSShiftAmt); else Rot = DAG.getNode(ISD::ROTR, DL, VT, LHSShiftArg, RHSShiftAmt); // If there is an AND of either shifted operand, apply it to the result. if (LHSMask.getNode() || RHSMask.getNode()) { APInt Mask = APInt::getAllOnesValue(OpSizeInBits); if (LHSMask.getNode()) { APInt RHSBits = APInt::getLowBitsSet(OpSizeInBits, LShVal); Mask &= cast(LHSMask)->getAPIntValue() | RHSBits; } if (RHSMask.getNode()) { APInt LHSBits = APInt::getHighBitsSet(OpSizeInBits, RShVal); Mask &= cast(RHSMask)->getAPIntValue() | LHSBits; } Rot = DAG.getNode(ISD::AND, DL, VT, Rot, DAG.getConstant(Mask, VT)); } return Rot.getNode(); } // If there is a mask here, and we have a variable shift, we can't be sure // that we're masking out the right stuff. if (LHSMask.getNode() || RHSMask.getNode()) return 0; // fold (or (shl x, y), (srl x, (sub 32, y))) -> (rotl x, y) // fold (or (shl x, y), (srl x, (sub 32, y))) -> (rotr x, (sub 32, y)) if (RHSShiftAmt.getOpcode() == ISD::SUB && LHSShiftAmt == RHSShiftAmt.getOperand(1)) { if (ConstantSDNode *SUBC = dyn_cast(RHSShiftAmt.getOperand(0))) { if (SUBC->getAPIntValue() == OpSizeInBits) { if (HasROTL) return DAG.getNode(ISD::ROTL, DL, VT, LHSShiftArg, LHSShiftAmt).getNode(); else return DAG.getNode(ISD::ROTR, DL, VT, LHSShiftArg, RHSShiftAmt).getNode(); } } } // fold (or (shl x, (sub 32, y)), (srl x, r)) -> (rotr x, y) // fold (or (shl x, (sub 32, y)), (srl x, r)) -> (rotl x, (sub 32, y)) if (LHSShiftAmt.getOpcode() == ISD::SUB && RHSShiftAmt == LHSShiftAmt.getOperand(1)) { if (ConstantSDNode *SUBC = dyn_cast(LHSShiftAmt.getOperand(0))) { if (SUBC->getAPIntValue() == OpSizeInBits) { if (HasROTR) return DAG.getNode(ISD::ROTR, DL, VT, LHSShiftArg, RHSShiftAmt).getNode(); else return DAG.getNode(ISD::ROTL, DL, VT, LHSShiftArg, LHSShiftAmt).getNode(); } } } // Look for sign/zext/any-extended or truncate cases: if ((LHSShiftAmt.getOpcode() == ISD::SIGN_EXTEND || LHSShiftAmt.getOpcode() == ISD::ZERO_EXTEND || LHSShiftAmt.getOpcode() == ISD::ANY_EXTEND || LHSShiftAmt.getOpcode() == ISD::TRUNCATE) && (RHSShiftAmt.getOpcode() == ISD::SIGN_EXTEND || RHSShiftAmt.getOpcode() == ISD::ZERO_EXTEND || RHSShiftAmt.getOpcode() == ISD::ANY_EXTEND || RHSShiftAmt.getOpcode() == ISD::TRUNCATE)) { SDValue LExtOp0 = LHSShiftAmt.getOperand(0); SDValue RExtOp0 = RHSShiftAmt.getOperand(0); if (RExtOp0.getOpcode() == ISD::SUB && RExtOp0.getOperand(1) == LExtOp0) { // fold (or (shl x, (*ext y)), (srl x, (*ext (sub 32, y)))) -> // (rotl x, y) // fold (or (shl x, (*ext y)), (srl x, (*ext (sub 32, y)))) -> // (rotr x, (sub 32, y)) if (ConstantSDNode *SUBC = dyn_cast(RExtOp0.getOperand(0))) { if (SUBC->getAPIntValue() == OpSizeInBits) { return DAG.getNode(HasROTL ? ISD::ROTL : ISD::ROTR, DL, VT, LHSShiftArg, HasROTL ? LHSShiftAmt : RHSShiftAmt).getNode(); } } } else if (LExtOp0.getOpcode() == ISD::SUB && RExtOp0 == LExtOp0.getOperand(1)) { // fold (or (shl x, (*ext (sub 32, y))), (srl x, (*ext y))) -> // (rotr x, y) // fold (or (shl x, (*ext (sub 32, y))), (srl x, (*ext y))) -> // (rotl x, (sub 32, y)) if (ConstantSDNode *SUBC = dyn_cast(LExtOp0.getOperand(0))) { if (SUBC->getAPIntValue() == OpSizeInBits) { return DAG.getNode(HasROTR ? ISD::ROTR : ISD::ROTL, DL, VT, LHSShiftArg, HasROTR ? RHSShiftAmt : LHSShiftAmt).getNode(); } } } } return 0; } SDValue DAGCombiner::visitXOR(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); SDValue LHS, RHS, CC; ConstantSDNode *N0C = dyn_cast(N0); ConstantSDNode *N1C = dyn_cast(N1); EVT VT = N0.getValueType(); // fold vector ops if (VT.isVector()) { SDValue FoldedVOp = SimplifyVBinOp(N); if (FoldedVOp.getNode()) return FoldedVOp; } // fold (xor undef, undef) -> 0. This is a common idiom (misuse). if (N0.getOpcode() == ISD::UNDEF && N1.getOpcode() == ISD::UNDEF) return DAG.getConstant(0, VT); // fold (xor x, undef) -> undef if (N0.getOpcode() == ISD::UNDEF) return N0; if (N1.getOpcode() == ISD::UNDEF) return N1; // fold (xor c1, c2) -> c1^c2 if (N0C && N1C) return DAG.FoldConstantArithmetic(ISD::XOR, VT, N0C, N1C); // canonicalize constant to RHS if (N0C && !N1C) return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, N1, N0); // fold (xor x, 0) -> x if (N1C && N1C->isNullValue()) return N0; // reassociate xor SDValue RXOR = ReassociateOps(ISD::XOR, N->getDebugLoc(), N0, N1); if (RXOR.getNode() != 0) return RXOR; // fold !(x cc y) -> (x !cc y) if (N1C && N1C->getAPIntValue() == 1 && isSetCCEquivalent(N0, LHS, RHS, CC)) { bool isInt = LHS.getValueType().isInteger(); ISD::CondCode NotCC = ISD::getSetCCInverse(cast(CC)->get(), isInt); if (!LegalOperations || TLI.isCondCodeLegal(NotCC, LHS.getValueType())) { switch (N0.getOpcode()) { default: llvm_unreachable("Unhandled SetCC Equivalent!"); case ISD::SETCC: return DAG.getSetCC(N->getDebugLoc(), VT, LHS, RHS, NotCC); case ISD::SELECT_CC: return DAG.getSelectCC(N->getDebugLoc(), LHS, RHS, N0.getOperand(2), N0.getOperand(3), NotCC); } } } // fold (not (zext (setcc x, y))) -> (zext (not (setcc x, y))) if (N1C && N1C->getAPIntValue() == 1 && N0.getOpcode() == ISD::ZERO_EXTEND && N0.getNode()->hasOneUse() && isSetCCEquivalent(N0.getOperand(0), LHS, RHS, CC)){ SDValue V = N0.getOperand(0); V = DAG.getNode(ISD::XOR, N0.getDebugLoc(), V.getValueType(), V, DAG.getConstant(1, V.getValueType())); AddToWorkList(V.getNode()); return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, V); } // fold (not (or x, y)) -> (and (not x), (not y)) iff x or y are setcc if (N1C && N1C->getAPIntValue() == 1 && VT == MVT::i1 && (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) { SDValue LHS = N0.getOperand(0), RHS = N0.getOperand(1); if (isOneUseSetCC(RHS) || isOneUseSetCC(LHS)) { unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND; LHS = DAG.getNode(ISD::XOR, LHS.getDebugLoc(), VT, LHS, N1); // LHS = ~LHS RHS = DAG.getNode(ISD::XOR, RHS.getDebugLoc(), VT, RHS, N1); // RHS = ~RHS AddToWorkList(LHS.getNode()); AddToWorkList(RHS.getNode()); return DAG.getNode(NewOpcode, N->getDebugLoc(), VT, LHS, RHS); } } // fold (not (or x, y)) -> (and (not x), (not y)) iff x or y are constants if (N1C && N1C->isAllOnesValue() && (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) { SDValue LHS = N0.getOperand(0), RHS = N0.getOperand(1); if (isa(RHS) || isa(LHS)) { unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND; LHS = DAG.getNode(ISD::XOR, LHS.getDebugLoc(), VT, LHS, N1); // LHS = ~LHS RHS = DAG.getNode(ISD::XOR, RHS.getDebugLoc(), VT, RHS, N1); // RHS = ~RHS AddToWorkList(LHS.getNode()); AddToWorkList(RHS.getNode()); return DAG.getNode(NewOpcode, N->getDebugLoc(), VT, LHS, RHS); } } // fold (xor (xor x, c1), c2) -> (xor x, (xor c1, c2)) if (N1C && N0.getOpcode() == ISD::XOR) { ConstantSDNode *N00C = dyn_cast(N0.getOperand(0)); ConstantSDNode *N01C = dyn_cast(N0.getOperand(1)); if (N00C) return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, N0.getOperand(1), DAG.getConstant(N1C->getAPIntValue() ^ N00C->getAPIntValue(), VT)); if (N01C) return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, N0.getOperand(0), DAG.getConstant(N1C->getAPIntValue() ^ N01C->getAPIntValue(), VT)); } // fold (xor x, x) -> 0 if (N0 == N1) return tryFoldToZero(N->getDebugLoc(), TLI, VT, DAG, LegalOperations); // Simplify: xor (op x...), (op y...) -> (op (xor x, y)) if (N0.getOpcode() == N1.getOpcode()) { SDValue Tmp = SimplifyBinOpWithSameOpcodeHands(N); if (Tmp.getNode()) return Tmp; } // Simplify the expression using non-local knowledge. if (!VT.isVector() && SimplifyDemandedBits(SDValue(N, 0))) return SDValue(N, 0); return SDValue(); } /// visitShiftByConstant - Handle transforms common to the three shifts, when /// the shift amount is a constant. SDValue DAGCombiner::visitShiftByConstant(SDNode *N, unsigned Amt) { SDNode *LHS = N->getOperand(0).getNode(); if (!LHS->hasOneUse()) return SDValue(); // We want to pull some binops through shifts, so that we have (and (shift)) // instead of (shift (and)), likewise for add, or, xor, etc. This sort of // thing happens with address calculations, so it's important to canonicalize // it. bool HighBitSet = false; // Can we transform this if the high bit is set? switch (LHS->getOpcode()) { default: return SDValue(); case ISD::OR: case ISD::XOR: HighBitSet = false; // We can only transform sra if the high bit is clear. break; case ISD::AND: HighBitSet = true; // We can only transform sra if the high bit is set. break; case ISD::ADD: if (N->getOpcode() != ISD::SHL) return SDValue(); // only shl(add) not sr[al](add). HighBitSet = false; // We can only transform sra if the high bit is clear. break; } // We require the RHS of the binop to be a constant as well. ConstantSDNode *BinOpCst = dyn_cast(LHS->getOperand(1)); if (!BinOpCst) return SDValue(); // FIXME: disable this unless the input to the binop is a shift by a constant. // If it is not a shift, it pessimizes some common cases like: // // void foo(int *X, int i) { X[i & 1235] = 1; } // int bar(int *X, int i) { return X[i & 255]; } SDNode *BinOpLHSVal = LHS->getOperand(0).getNode(); if ((BinOpLHSVal->getOpcode() != ISD::SHL && BinOpLHSVal->getOpcode() != ISD::SRA && BinOpLHSVal->getOpcode() != ISD::SRL) || !isa(BinOpLHSVal->getOperand(1))) return SDValue(); EVT VT = N->getValueType(0); // If this is a signed shift right, and the high bit is modified by the // logical operation, do not perform the transformation. The highBitSet // boolean indicates the value of the high bit of the constant which would // cause it to be modified for this operation. if (N->getOpcode() == ISD::SRA) { bool BinOpRHSSignSet = BinOpCst->getAPIntValue().isNegative(); if (BinOpRHSSignSet != HighBitSet) return SDValue(); } // Fold the constants, shifting the binop RHS by the shift amount. SDValue NewRHS = DAG.getNode(N->getOpcode(), LHS->getOperand(1).getDebugLoc(), N->getValueType(0), LHS->getOperand(1), N->getOperand(1)); // Create the new shift. SDValue NewShift = DAG.getNode(N->getOpcode(), LHS->getOperand(0).getDebugLoc(), VT, LHS->getOperand(0), N->getOperand(1)); // Create the new binop. return DAG.getNode(LHS->getOpcode(), N->getDebugLoc(), VT, NewShift, NewRHS); } SDValue DAGCombiner::visitSHL(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); ConstantSDNode *N0C = dyn_cast(N0); ConstantSDNode *N1C = dyn_cast(N1); EVT VT = N0.getValueType(); unsigned OpSizeInBits = VT.getScalarType().getSizeInBits(); // fold (shl c1, c2) -> c1< 0 if (N0C && N0C->isNullValue()) return N0; // fold (shl x, c >= size(x)) -> undef if (N1C && N1C->getZExtValue() >= OpSizeInBits) return DAG.getUNDEF(VT); // fold (shl x, 0) -> x if (N1C && N1C->isNullValue()) return N0; // if (shl x, c) is known to be zero, return 0 if (DAG.MaskedValueIsZero(SDValue(N, 0), APInt::getAllOnesValue(OpSizeInBits))) return DAG.getConstant(0, VT); // fold (shl x, (trunc (and y, c))) -> (shl x, (and (trunc y), (trunc c))). if (N1.getOpcode() == ISD::TRUNCATE && N1.getOperand(0).getOpcode() == ISD::AND && N1.hasOneUse() && N1.getOperand(0).hasOneUse()) { SDValue N101 = N1.getOperand(0).getOperand(1); if (ConstantSDNode *N101C = dyn_cast(N101)) { EVT TruncVT = N1.getValueType(); SDValue N100 = N1.getOperand(0).getOperand(0); APInt TruncC = N101C->getAPIntValue(); TruncC = TruncC.trunc(TruncVT.getSizeInBits()); return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0, DAG.getNode(ISD::AND, N->getDebugLoc(), TruncVT, DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), TruncVT, N100), DAG.getConstant(TruncC, TruncVT))); } } if (N1C && SimplifyDemandedBits(SDValue(N, 0))) return SDValue(N, 0); // fold (shl (shl x, c1), c2) -> 0 or (shl x, (add c1, c2)) if (N1C && N0.getOpcode() == ISD::SHL && N0.getOperand(1).getOpcode() == ISD::Constant) { uint64_t c1 = cast(N0.getOperand(1))->getZExtValue(); uint64_t c2 = N1C->getZExtValue(); if (c1 + c2 >= OpSizeInBits) return DAG.getConstant(0, VT); return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0.getOperand(0), DAG.getConstant(c1 + c2, N1.getValueType())); } // fold (shl (ext (shl x, c1)), c2) -> (ext (shl x, (add c1, c2))) // For this to be valid, the second form must not preserve any of the bits // that are shifted out by the inner shift in the first form. This means // the outer shift size must be >= the number of bits added by the ext. // As a corollary, we don't care what kind of ext it is. if (N1C && (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND || N0.getOpcode() == ISD::SIGN_EXTEND) && N0.getOperand(0).getOpcode() == ISD::SHL && isa(N0.getOperand(0)->getOperand(1))) { uint64_t c1 = cast(N0.getOperand(0)->getOperand(1))->getZExtValue(); uint64_t c2 = N1C->getZExtValue(); EVT InnerShiftVT = N0.getOperand(0).getValueType(); uint64_t InnerShiftSize = InnerShiftVT.getScalarType().getSizeInBits(); if (c2 >= OpSizeInBits - InnerShiftSize) { if (c1 + c2 >= OpSizeInBits) return DAG.getConstant(0, VT); return DAG.getNode(ISD::SHL, N0->getDebugLoc(), VT, DAG.getNode(N0.getOpcode(), N0->getDebugLoc(), VT, N0.getOperand(0)->getOperand(0)), DAG.getConstant(c1 + c2, N1.getValueType())); } } // fold (shl (srl x, c1), c2) -> (shl (and x, (shl -1, c1)), (sub c2, c1)) or // (srl (and x, (shl -1, c1)), (sub c1, c2)) if (N1C && N0.getOpcode() == ISD::SRL && N0.getOperand(1).getOpcode() == ISD::Constant) { uint64_t c1 = cast(N0.getOperand(1))->getZExtValue(); if (c1 < VT.getSizeInBits()) { uint64_t c2 = N1C->getZExtValue(); SDValue HiBitsMask = DAG.getConstant(APInt::getHighBitsSet(VT.getSizeInBits(), VT.getSizeInBits() - c1), VT); SDValue Mask = DAG.getNode(ISD::AND, N0.getDebugLoc(), VT, N0.getOperand(0), HiBitsMask); if (c2 > c1) return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, Mask, DAG.getConstant(c2-c1, N1.getValueType())); else return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, Mask, DAG.getConstant(c1-c2, N1.getValueType())); } } // fold (shl (sra x, c1), c1) -> (and x, (shl -1, c1)) if (N1C && N0.getOpcode() == ISD::SRA && N1 == N0.getOperand(1)) { SDValue HiBitsMask = DAG.getConstant(APInt::getHighBitsSet(VT.getSizeInBits(), VT.getSizeInBits() - N1C->getZExtValue()), VT); return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0.getOperand(0), HiBitsMask); } if (N1C) { SDValue NewSHL = visitShiftByConstant(N, N1C->getZExtValue()); if (NewSHL.getNode()) return NewSHL; } return SDValue(); } SDValue DAGCombiner::visitSRA(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); ConstantSDNode *N0C = dyn_cast(N0); ConstantSDNode *N1C = dyn_cast(N1); EVT VT = N0.getValueType(); unsigned OpSizeInBits = VT.getScalarType().getSizeInBits(); // fold (sra c1, c2) -> (sra c1, c2) if (N0C && N1C) return DAG.FoldConstantArithmetic(ISD::SRA, VT, N0C, N1C); // fold (sra 0, x) -> 0 if (N0C && N0C->isNullValue()) return N0; // fold (sra -1, x) -> -1 if (N0C && N0C->isAllOnesValue()) return N0; // fold (sra x, (setge c, size(x))) -> undef if (N1C && N1C->getZExtValue() >= OpSizeInBits) return DAG.getUNDEF(VT); // fold (sra x, 0) -> x if (N1C && N1C->isNullValue()) return N0; // fold (sra (shl x, c1), c1) -> sext_inreg for some c1 and target supports // sext_inreg. if (N1C && N0.getOpcode() == ISD::SHL && N1 == N0.getOperand(1)) { unsigned LowBits = OpSizeInBits - (unsigned)N1C->getZExtValue(); EVT ExtVT = EVT::getIntegerVT(*DAG.getContext(), LowBits); if (VT.isVector()) ExtVT = EVT::getVectorVT(*DAG.getContext(), ExtVT, VT.getVectorNumElements()); if ((!LegalOperations || TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, ExtVT))) return DAG.getNode(ISD::SIGN_EXTEND_INREG, N->getDebugLoc(), VT, N0.getOperand(0), DAG.getValueType(ExtVT)); } // fold (sra (sra x, c1), c2) -> (sra x, (add c1, c2)) if (N1C && N0.getOpcode() == ISD::SRA) { if (ConstantSDNode *C1 = dyn_cast(N0.getOperand(1))) { unsigned Sum = N1C->getZExtValue() + C1->getZExtValue(); if (Sum >= OpSizeInBits) Sum = OpSizeInBits-1; return DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, N0.getOperand(0), DAG.getConstant(Sum, N1C->getValueType(0))); } } // fold (sra (shl X, m), (sub result_size, n)) // -> (sign_extend (trunc (shl X, (sub (sub result_size, n), m)))) for // result_size - n != m. // If truncate is free for the target sext(shl) is likely to result in better // code. if (N0.getOpcode() == ISD::SHL) { // Get the two constanst of the shifts, CN0 = m, CN = n. const ConstantSDNode *N01C = dyn_cast(N0.getOperand(1)); if (N01C && N1C) { // Determine what the truncate's result bitsize and type would be. EVT TruncVT = EVT::getIntegerVT(*DAG.getContext(), OpSizeInBits - N1C->getZExtValue()); // Determine the residual right-shift amount. signed ShiftAmt = N1C->getZExtValue() - N01C->getZExtValue(); // If the shift is not a no-op (in which case this should be just a sign // extend already), the truncated to type is legal, sign_extend is legal // on that type, and the truncate to that type is both legal and free, // perform the transform. if ((ShiftAmt > 0) && TLI.isOperationLegalOrCustom(ISD::SIGN_EXTEND, TruncVT) && TLI.isOperationLegalOrCustom(ISD::TRUNCATE, VT) && TLI.isTruncateFree(VT, TruncVT)) { SDValue Amt = DAG.getConstant(ShiftAmt, getShiftAmountTy(N0.getOperand(0).getValueType())); SDValue Shift = DAG.getNode(ISD::SRL, N0.getDebugLoc(), VT, N0.getOperand(0), Amt); SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), TruncVT, Shift); return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), N->getValueType(0), Trunc); } } } // fold (sra x, (trunc (and y, c))) -> (sra x, (and (trunc y), (trunc c))). if (N1.getOpcode() == ISD::TRUNCATE && N1.getOperand(0).getOpcode() == ISD::AND && N1.hasOneUse() && N1.getOperand(0).hasOneUse()) { SDValue N101 = N1.getOperand(0).getOperand(1); if (ConstantSDNode *N101C = dyn_cast(N101)) { EVT TruncVT = N1.getValueType(); SDValue N100 = N1.getOperand(0).getOperand(0); APInt TruncC = N101C->getAPIntValue(); TruncC = TruncC.trunc(TruncVT.getScalarType().getSizeInBits()); return DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, N0, DAG.getNode(ISD::AND, N->getDebugLoc(), TruncVT, DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), TruncVT, N100), DAG.getConstant(TruncC, TruncVT))); } } // fold (sra (trunc (sr x, c1)), c2) -> (trunc (sra x, c1+c2)) // if c1 is equal to the number of bits the trunc removes if (N0.getOpcode() == ISD::TRUNCATE && (N0.getOperand(0).getOpcode() == ISD::SRL || N0.getOperand(0).getOpcode() == ISD::SRA) && N0.getOperand(0).hasOneUse() && N0.getOperand(0).getOperand(1).hasOneUse() && N1C && isa(N0.getOperand(0).getOperand(1))) { EVT LargeVT = N0.getOperand(0).getValueType(); ConstantSDNode *LargeShiftAmt = cast(N0.getOperand(0).getOperand(1)); if (LargeVT.getScalarType().getSizeInBits() - OpSizeInBits == LargeShiftAmt->getZExtValue()) { SDValue Amt = DAG.getConstant(LargeShiftAmt->getZExtValue() + N1C->getZExtValue(), getShiftAmountTy(N0.getOperand(0).getOperand(0).getValueType())); SDValue SRA = DAG.getNode(ISD::SRA, N->getDebugLoc(), LargeVT, N0.getOperand(0).getOperand(0), Amt); return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, SRA); } } // Simplify, based on bits shifted out of the LHS. if (N1C && SimplifyDemandedBits(SDValue(N, 0))) return SDValue(N, 0); // If the sign bit is known to be zero, switch this to a SRL. if (DAG.SignBitIsZero(N0)) return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0, N1); if (N1C) { SDValue NewSRA = visitShiftByConstant(N, N1C->getZExtValue()); if (NewSRA.getNode()) return NewSRA; } return SDValue(); } SDValue DAGCombiner::visitSRL(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); ConstantSDNode *N0C = dyn_cast(N0); ConstantSDNode *N1C = dyn_cast(N1); EVT VT = N0.getValueType(); unsigned OpSizeInBits = VT.getScalarType().getSizeInBits(); // fold (srl c1, c2) -> c1 >>u c2 if (N0C && N1C) return DAG.FoldConstantArithmetic(ISD::SRL, VT, N0C, N1C); // fold (srl 0, x) -> 0 if (N0C && N0C->isNullValue()) return N0; // fold (srl x, c >= size(x)) -> undef if (N1C && N1C->getZExtValue() >= OpSizeInBits) return DAG.getUNDEF(VT); // fold (srl x, 0) -> x if (N1C && N1C->isNullValue()) return N0; // if (srl x, c) is known to be zero, return 0 if (N1C && DAG.MaskedValueIsZero(SDValue(N, 0), APInt::getAllOnesValue(OpSizeInBits))) return DAG.getConstant(0, VT); // fold (srl (srl x, c1), c2) -> 0 or (srl x, (add c1, c2)) if (N1C && N0.getOpcode() == ISD::SRL && N0.getOperand(1).getOpcode() == ISD::Constant) { uint64_t c1 = cast(N0.getOperand(1))->getZExtValue(); uint64_t c2 = N1C->getZExtValue(); if (c1 + c2 >= OpSizeInBits) return DAG.getConstant(0, VT); return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0.getOperand(0), DAG.getConstant(c1 + c2, N1.getValueType())); } // fold (srl (trunc (srl x, c1)), c2) -> 0 or (trunc (srl x, (add c1, c2))) if (N1C && N0.getOpcode() == ISD::TRUNCATE && N0.getOperand(0).getOpcode() == ISD::SRL && isa(N0.getOperand(0)->getOperand(1))) { uint64_t c1 = cast(N0.getOperand(0)->getOperand(1))->getZExtValue(); uint64_t c2 = N1C->getZExtValue(); EVT InnerShiftVT = N0.getOperand(0).getValueType(); EVT ShiftCountVT = N0.getOperand(0)->getOperand(1).getValueType(); uint64_t InnerShiftSize = InnerShiftVT.getScalarType().getSizeInBits(); // This is only valid if the OpSizeInBits + c1 = size of inner shift. if (c1 + OpSizeInBits == InnerShiftSize) { if (c1 + c2 >= InnerShiftSize) return DAG.getConstant(0, VT); return DAG.getNode(ISD::TRUNCATE, N0->getDebugLoc(), VT, DAG.getNode(ISD::SRL, N0->getDebugLoc(), InnerShiftVT, N0.getOperand(0)->getOperand(0), DAG.getConstant(c1 + c2, ShiftCountVT))); } } // fold (srl (shl x, c), c) -> (and x, cst2) if (N1C && N0.getOpcode() == ISD::SHL && N0.getOperand(1) == N1 && N0.getValueSizeInBits() <= 64) { uint64_t ShAmt = N1C->getZExtValue()+64-N0.getValueSizeInBits(); return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0.getOperand(0), DAG.getConstant(~0ULL >> ShAmt, VT)); } // fold (srl (anyextend x), c) -> (anyextend (srl x, c)) if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) { // Shifting in all undef bits? EVT SmallVT = N0.getOperand(0).getValueType(); if (N1C->getZExtValue() >= SmallVT.getSizeInBits()) return DAG.getUNDEF(VT); if (!LegalTypes || TLI.isTypeDesirableForOp(ISD::SRL, SmallVT)) { SDValue SmallShift = DAG.getNode(ISD::SRL, N0.getDebugLoc(), SmallVT, N0.getOperand(0), N1); AddToWorkList(SmallShift.getNode()); return DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, SmallShift); } } // fold (srl (sra X, Y), 31) -> (srl X, 31). This srl only looks at the sign // bit, which is unmodified by sra. if (N1C && N1C->getZExtValue() + 1 == VT.getSizeInBits()) { if (N0.getOpcode() == ISD::SRA) return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0.getOperand(0), N1); } // fold (srl (ctlz x), "5") -> x iff x has one bit set (the low bit). if (N1C && N0.getOpcode() == ISD::CTLZ && N1C->getAPIntValue() == Log2_32(VT.getSizeInBits())) { APInt KnownZero, KnownOne; APInt Mask = APInt::getAllOnesValue(VT.getScalarType().getSizeInBits()); DAG.ComputeMaskedBits(N0.getOperand(0), Mask, KnownZero, KnownOne); // If any of the input bits are KnownOne, then the input couldn't be all // zeros, thus the result of the srl will always be zero. if (KnownOne.getBoolValue()) return DAG.getConstant(0, VT); // If all of the bits input the to ctlz node are known to be zero, then // the result of the ctlz is "32" and the result of the shift is one. APInt UnknownBits = ~KnownZero & Mask; if (UnknownBits == 0) return DAG.getConstant(1, VT); // Otherwise, check to see if there is exactly one bit input to the ctlz. if ((UnknownBits & (UnknownBits - 1)) == 0) { // Okay, we know that only that the single bit specified by UnknownBits // could be set on input to the CTLZ node. If this bit is set, the SRL // will return 0, if it is clear, it returns 1. Change the CTLZ/SRL pair // to an SRL/XOR pair, which is likely to simplify more. unsigned ShAmt = UnknownBits.countTrailingZeros(); SDValue Op = N0.getOperand(0); if (ShAmt) { Op = DAG.getNode(ISD::SRL, N0.getDebugLoc(), VT, Op, DAG.getConstant(ShAmt, getShiftAmountTy(Op.getValueType()))); AddToWorkList(Op.getNode()); } return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, Op, DAG.getConstant(1, VT)); } } // fold (srl x, (trunc (and y, c))) -> (srl x, (and (trunc y), (trunc c))). if (N1.getOpcode() == ISD::TRUNCATE && N1.getOperand(0).getOpcode() == ISD::AND && N1.hasOneUse() && N1.getOperand(0).hasOneUse()) { SDValue N101 = N1.getOperand(0).getOperand(1); if (ConstantSDNode *N101C = dyn_cast(N101)) { EVT TruncVT = N1.getValueType(); SDValue N100 = N1.getOperand(0).getOperand(0); APInt TruncC = N101C->getAPIntValue(); TruncC = TruncC.trunc(TruncVT.getSizeInBits()); return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0, DAG.getNode(ISD::AND, N->getDebugLoc(), TruncVT, DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), TruncVT, N100), DAG.getConstant(TruncC, TruncVT))); } } // fold operands of srl based on knowledge that the low bits are not // demanded. if (N1C && SimplifyDemandedBits(SDValue(N, 0))) return SDValue(N, 0); if (N1C) { SDValue NewSRL = visitShiftByConstant(N, N1C->getZExtValue()); if (NewSRL.getNode()) return NewSRL; } // Attempt to convert a srl of a load into a narrower zero-extending load. SDValue NarrowLoad = ReduceLoadWidth(N); if (NarrowLoad.getNode()) return NarrowLoad; // Here is a common situation. We want to optimize: // // %a = ... // %b = and i32 %a, 2 // %c = srl i32 %b, 1 // brcond i32 %c ... // // into // // %a = ... // %b = and %a, 2 // %c = setcc eq %b, 0 // brcond %c ... // // However when after the source operand of SRL is optimized into AND, the SRL // itself may not be optimized further. Look for it and add the BRCOND into // the worklist. if (N->hasOneUse()) { SDNode *Use = *N->use_begin(); if (Use->getOpcode() == ISD::BRCOND) AddToWorkList(Use); else if (Use->getOpcode() == ISD::TRUNCATE && Use->hasOneUse()) { // Also look pass the truncate. Use = *Use->use_begin(); if (Use->getOpcode() == ISD::BRCOND) AddToWorkList(Use); } } return SDValue(); } SDValue DAGCombiner::visitCTLZ(SDNode *N) { SDValue N0 = N->getOperand(0); EVT VT = N->getValueType(0); // fold (ctlz c1) -> c2 if (isa(N0)) return DAG.getNode(ISD::CTLZ, N->getDebugLoc(), VT, N0); return SDValue(); } SDValue DAGCombiner::visitCTTZ(SDNode *N) { SDValue N0 = N->getOperand(0); EVT VT = N->getValueType(0); // fold (cttz c1) -> c2 if (isa(N0)) return DAG.getNode(ISD::CTTZ, N->getDebugLoc(), VT, N0); return SDValue(); } SDValue DAGCombiner::visitCTPOP(SDNode *N) { SDValue N0 = N->getOperand(0); EVT VT = N->getValueType(0); // fold (ctpop c1) -> c2 if (isa(N0)) return DAG.getNode(ISD::CTPOP, N->getDebugLoc(), VT, N0); return SDValue(); } SDValue DAGCombiner::visitSELECT(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); SDValue N2 = N->getOperand(2); ConstantSDNode *N0C = dyn_cast(N0); ConstantSDNode *N1C = dyn_cast(N1); ConstantSDNode *N2C = dyn_cast(N2); EVT VT = N->getValueType(0); EVT VT0 = N0.getValueType(); // fold (select C, X, X) -> X if (N1 == N2) return N1; // fold (select true, X, Y) -> X if (N0C && !N0C->isNullValue()) return N1; // fold (select false, X, Y) -> Y if (N0C && N0C->isNullValue()) return N2; // fold (select C, 1, X) -> (or C, X) if (VT == MVT::i1 && N1C && N1C->getAPIntValue() == 1) return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N0, N2); // fold (select C, 0, 1) -> (xor C, 1) if (VT.isInteger() && (VT0 == MVT::i1 || (VT0.isInteger() && TLI.getBooleanContents() == TargetLowering::ZeroOrOneBooleanContent)) && N1C && N2C && N1C->isNullValue() && N2C->getAPIntValue() == 1) { SDValue XORNode; if (VT == VT0) return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT0, N0, DAG.getConstant(1, VT0)); XORNode = DAG.getNode(ISD::XOR, N0.getDebugLoc(), VT0, N0, DAG.getConstant(1, VT0)); AddToWorkList(XORNode.getNode()); if (VT.bitsGT(VT0)) return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, XORNode); return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, XORNode); } // fold (select C, 0, X) -> (and (not C), X) if (VT == VT0 && VT == MVT::i1 && N1C && N1C->isNullValue()) { SDValue NOTNode = DAG.getNOT(N0.getDebugLoc(), N0, VT); AddToWorkList(NOTNode.getNode()); return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, NOTNode, N2); } // fold (select C, X, 1) -> (or (not C), X) if (VT == VT0 && VT == MVT::i1 && N2C && N2C->getAPIntValue() == 1) { SDValue NOTNode = DAG.getNOT(N0.getDebugLoc(), N0, VT); AddToWorkList(NOTNode.getNode()); return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, NOTNode, N1); } // fold (select C, X, 0) -> (and C, X) if (VT == MVT::i1 && N2C && N2C->isNullValue()) return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0, N1); // fold (select X, X, Y) -> (or X, Y) // fold (select X, 1, Y) -> (or X, Y) if (VT == MVT::i1 && (N0 == N1 || (N1C && N1C->getAPIntValue() == 1))) return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N0, N2); // fold (select X, Y, X) -> (and X, Y) // fold (select X, Y, 0) -> (and X, Y) if (VT == MVT::i1 && (N0 == N2 || (N2C && N2C->getAPIntValue() == 0))) return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0, N1); // If we can fold this based on the true/false value, do so. if (SimplifySelectOps(N, N1, N2)) return SDValue(N, 0); // Don't revisit N. // fold selects based on a setcc into other things, such as min/max/abs if (N0.getOpcode() == ISD::SETCC) { // FIXME: // Check against MVT::Other for SELECT_CC, which is a workaround for targets // having to say they don't support SELECT_CC on every type the DAG knows // about, since there is no way to mark an opcode illegal at all value types if (TLI.isOperationLegalOrCustom(ISD::SELECT_CC, MVT::Other) && TLI.isOperationLegalOrCustom(ISD::SELECT_CC, VT)) return DAG.getNode(ISD::SELECT_CC, N->getDebugLoc(), VT, N0.getOperand(0), N0.getOperand(1), N1, N2, N0.getOperand(2)); return SimplifySelect(N->getDebugLoc(), N0, N1, N2); } return SDValue(); } SDValue DAGCombiner::visitSELECT_CC(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); SDValue N2 = N->getOperand(2); SDValue N3 = N->getOperand(3); SDValue N4 = N->getOperand(4); ISD::CondCode CC = cast(N4)->get(); // fold select_cc lhs, rhs, x, x, cc -> x if (N2 == N3) return N2; // Determine if the condition we're dealing with is constant SDValue SCC = SimplifySetCC(TLI.getSetCCResultType(N0.getValueType()), N0, N1, CC, N->getDebugLoc(), false); if (SCC.getNode()) AddToWorkList(SCC.getNode()); if (ConstantSDNode *SCCC = dyn_cast_or_null(SCC.getNode())) { if (!SCCC->isNullValue()) return N2; // cond always true -> true val else return N3; // cond always false -> false val } // Fold to a simpler select_cc if (SCC.getNode() && SCC.getOpcode() == ISD::SETCC) return DAG.getNode(ISD::SELECT_CC, N->getDebugLoc(), N2.getValueType(), SCC.getOperand(0), SCC.getOperand(1), N2, N3, SCC.getOperand(2)); // If we can fold this based on the true/false value, do so. if (SimplifySelectOps(N, N2, N3)) return SDValue(N, 0); // Don't revisit N. // fold select_cc into other things, such as min/max/abs return SimplifySelectCC(N->getDebugLoc(), N0, N1, N2, N3, CC); } SDValue DAGCombiner::visitSETCC(SDNode *N) { return SimplifySetCC(N->getValueType(0), N->getOperand(0), N->getOperand(1), cast(N->getOperand(2))->get(), N->getDebugLoc()); } // ExtendUsesToFormExtLoad - Trying to extend uses of a load to enable this: // "fold ({s|z|a}ext (load x)) -> ({s|z|a}ext (truncate ({s|z|a}extload x)))" // transformation. Returns true if extension are possible and the above // mentioned transformation is profitable. static bool ExtendUsesToFormExtLoad(SDNode *N, SDValue N0, unsigned ExtOpc, SmallVector &ExtendNodes, const TargetLowering &TLI) { bool HasCopyToRegUses = false; bool isTruncFree = TLI.isTruncateFree(N->getValueType(0), N0.getValueType()); for (SDNode::use_iterator UI = N0.getNode()->use_begin(), UE = N0.getNode()->use_end(); UI != UE; ++UI) { SDNode *User = *UI; if (User == N) continue; if (UI.getUse().getResNo() != N0.getResNo()) continue; // FIXME: Only extend SETCC N, N and SETCC N, c for now. if (ExtOpc != ISD::ANY_EXTEND && User->getOpcode() == ISD::SETCC) { ISD::CondCode CC = cast(User->getOperand(2))->get(); if (ExtOpc == ISD::ZERO_EXTEND && ISD::isSignedIntSetCC(CC)) // Sign bits will be lost after a zext. return false; bool Add = false; for (unsigned i = 0; i != 2; ++i) { SDValue UseOp = User->getOperand(i); if (UseOp == N0) continue; if (!isa(UseOp)) return false; Add = true; } if (Add) ExtendNodes.push_back(User); continue; } // If truncates aren't free and there are users we can't // extend, it isn't worthwhile. if (!isTruncFree) return false; // Remember if this value is live-out. if (User->getOpcode() == ISD::CopyToReg) HasCopyToRegUses = true; } if (HasCopyToRegUses) { bool BothLiveOut = false; for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end(); UI != UE; ++UI) { SDUse &Use = UI.getUse(); if (Use.getResNo() == 0 && Use.getUser()->getOpcode() == ISD::CopyToReg) { BothLiveOut = true; break; } } if (BothLiveOut) // Both unextended and extended values are live out. There had better be // a good reason for the transformation. return ExtendNodes.size(); } return true; } SDValue DAGCombiner::visitSIGN_EXTEND(SDNode *N) { SDValue N0 = N->getOperand(0); EVT VT = N->getValueType(0); // fold (sext c1) -> c1 if (isa(N0)) return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, N0); // fold (sext (sext x)) -> (sext x) // fold (sext (aext x)) -> (sext x) if (N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND) return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, N0.getOperand(0)); if (N0.getOpcode() == ISD::TRUNCATE) { // fold (sext (truncate (load x))) -> (sext (smaller load x)) // fold (sext (truncate (srl (load x), c))) -> (sext (smaller load (x+c/n))) SDValue NarrowLoad = ReduceLoadWidth(N0.getNode()); if (NarrowLoad.getNode()) { SDNode* oye = N0.getNode()->getOperand(0).getNode(); if (NarrowLoad.getNode() != N0.getNode()) { CombineTo(N0.getNode(), NarrowLoad); // CombineTo deleted the truncate, if needed, but not what's under it. AddToWorkList(oye); } return SDValue(N, 0); // Return N so it doesn't get rechecked! } // See if the value being truncated is already sign extended. If so, just // eliminate the trunc/sext pair. SDValue Op = N0.getOperand(0); unsigned OpBits = Op.getValueType().getScalarType().getSizeInBits(); unsigned MidBits = N0.getValueType().getScalarType().getSizeInBits(); unsigned DestBits = VT.getScalarType().getSizeInBits(); unsigned NumSignBits = DAG.ComputeNumSignBits(Op); if (OpBits == DestBits) { // Op is i32, Mid is i8, and Dest is i32. If Op has more than 24 sign // bits, it is already ready. if (NumSignBits > DestBits-MidBits) return Op; } else if (OpBits < DestBits) { // Op is i32, Mid is i8, and Dest is i64. If Op has more than 24 sign // bits, just sext from i32. if (NumSignBits > OpBits-MidBits) return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, Op); } else { // Op is i64, Mid is i8, and Dest is i32. If Op has more than 56 sign // bits, just truncate to i32. if (NumSignBits > OpBits-MidBits) return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, Op); } // fold (sext (truncate x)) -> (sextinreg x). if (!LegalOperations || TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, N0.getValueType())) { if (OpBits < DestBits) Op = DAG.getNode(ISD::ANY_EXTEND, N0.getDebugLoc(), VT, Op); else if (OpBits > DestBits) Op = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), VT, Op); return DAG.getNode(ISD::SIGN_EXTEND_INREG, N->getDebugLoc(), VT, Op, DAG.getValueType(N0.getValueType())); } } // fold (sext (load x)) -> (sext (truncate (sextload x))) // None of the supported targets knows how to perform load and sign extend // on vectors in one instruction. We only perform this transformation on // scalars. if (ISD::isNON_EXTLoad(N0.getNode()) && !VT.isVector() && ((!LegalOperations && !cast(N0)->isVolatile()) || TLI.isLoadExtLegal(ISD::SEXTLOAD, N0.getValueType()))) { bool DoXform = true; SmallVector SetCCs; if (!N0.hasOneUse()) DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::SIGN_EXTEND, SetCCs, TLI); if (DoXform) { LoadSDNode *LN0 = cast(N0); SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, N->getDebugLoc(), VT, LN0->getChain(), LN0->getBasePtr(), LN0->getPointerInfo(), N0.getValueType(), LN0->isVolatile(), LN0->isNonTemporal(), LN0->getAlignment()); CombineTo(N, ExtLoad); SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), N0.getValueType(), ExtLoad); CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1)); // Extend SetCC uses if necessary. for (unsigned i = 0, e = SetCCs.size(); i != e; ++i) { SDNode *SetCC = SetCCs[i]; SmallVector Ops; for (unsigned j = 0; j != 2; ++j) { SDValue SOp = SetCC->getOperand(j); if (SOp == Trunc) Ops.push_back(ExtLoad); else Ops.push_back(DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, SOp)); } Ops.push_back(SetCC->getOperand(2)); CombineTo(SetCC, DAG.getNode(ISD::SETCC, N->getDebugLoc(), SetCC->getValueType(0), &Ops[0], Ops.size())); } return SDValue(N, 0); // Return N so it doesn't get rechecked! } } // fold (sext (sextload x)) -> (sext (truncate (sextload x))) // fold (sext ( extload x)) -> (sext (truncate (sextload x))) if ((ISD::isSEXTLoad(N0.getNode()) || ISD::isEXTLoad(N0.getNode())) && ISD::isUNINDEXEDLoad(N0.getNode()) && N0.hasOneUse()) { LoadSDNode *LN0 = cast(N0); EVT MemVT = LN0->getMemoryVT(); if ((!LegalOperations && !LN0->isVolatile()) || TLI.isLoadExtLegal(ISD::SEXTLOAD, MemVT)) { SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, N->getDebugLoc(), VT, LN0->getChain(), LN0->getBasePtr(), LN0->getPointerInfo(), MemVT, LN0->isVolatile(), LN0->isNonTemporal(), LN0->getAlignment()); CombineTo(N, ExtLoad); CombineTo(N0.getNode(), DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), N0.getValueType(), ExtLoad), ExtLoad.getValue(1)); return SDValue(N, 0); // Return N so it doesn't get rechecked! } } if (N0.getOpcode() == ISD::SETCC) { // sext(setcc) -> sext_in_reg(vsetcc) for vectors. // Only do this before legalize for now. if (VT.isVector() && !LegalOperations) { EVT N0VT = N0.getOperand(0).getValueType(); // We know that the # elements of the results is the same as the // # elements of the compare (and the # elements of the compare result // for that matter). Check to see that they are the same size. If so, // we know that the element size of the sext'd result matches the // element size of the compare operands. if (VT.getSizeInBits() == N0VT.getSizeInBits()) return DAG.getVSetCC(N->getDebugLoc(), VT, N0.getOperand(0), N0.getOperand(1), cast(N0.getOperand(2))->get()); // If the desired elements are smaller or larger than the source // elements we can use a matching integer vector type and then // truncate/sign extend else { EVT MatchingElementType = EVT::getIntegerVT(*DAG.getContext(), N0VT.getScalarType().getSizeInBits()); EVT MatchingVectorType = EVT::getVectorVT(*DAG.getContext(), MatchingElementType, N0VT.getVectorNumElements()); SDValue VsetCC = DAG.getVSetCC(N->getDebugLoc(), MatchingVectorType, N0.getOperand(0), N0.getOperand(1), cast(N0.getOperand(2))->get()); return DAG.getSExtOrTrunc(VsetCC, N->getDebugLoc(), VT); } } // sext(setcc x, y, cc) -> (select_cc x, y, -1, 0, cc) unsigned ElementWidth = VT.getScalarType().getSizeInBits(); SDValue NegOne = DAG.getConstant(APInt::getAllOnesValue(ElementWidth), VT); SDValue SCC = SimplifySelectCC(N->getDebugLoc(), N0.getOperand(0), N0.getOperand(1), NegOne, DAG.getConstant(0, VT), cast(N0.getOperand(2))->get(), true); if (SCC.getNode()) return SCC; if (!LegalOperations || TLI.isOperationLegal(ISD::SETCC, TLI.getSetCCResultType(VT))) return DAG.getNode(ISD::SELECT, N->getDebugLoc(), VT, DAG.getSetCC(N->getDebugLoc(), TLI.getSetCCResultType(VT), N0.getOperand(0), N0.getOperand(1), cast(N0.getOperand(2))->get()), NegOne, DAG.getConstant(0, VT)); } // fold (sext x) -> (zext x) if the sign bit is known zero. if ((!LegalOperations || TLI.isOperationLegal(ISD::ZERO_EXTEND, VT)) && DAG.SignBitIsZero(N0)) return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, N0); return SDValue(); } SDValue DAGCombiner::visitZERO_EXTEND(SDNode *N) { SDValue N0 = N->getOperand(0); EVT VT = N->getValueType(0); // fold (zext c1) -> c1 if (isa(N0)) return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, N0); // fold (zext (zext x)) -> (zext x) // fold (zext (aext x)) -> (zext x) if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND) return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, N0.getOperand(0)); // fold (zext (truncate (load x))) -> (zext (smaller load x)) // fold (zext (truncate (srl (load x), c))) -> (zext (small load (x+c/n))) if (N0.getOpcode() == ISD::TRUNCATE) { SDValue NarrowLoad = ReduceLoadWidth(N0.getNode()); if (NarrowLoad.getNode()) { SDNode* oye = N0.getNode()->getOperand(0).getNode(); if (NarrowLoad.getNode() != N0.getNode()) { CombineTo(N0.getNode(), NarrowLoad); // CombineTo deleted the truncate, if needed, but not what's under it. AddToWorkList(oye); } return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, NarrowLoad); } } // fold (zext (truncate x)) -> (and x, mask) if (N0.getOpcode() == ISD::TRUNCATE && (!LegalOperations || TLI.isOperationLegal(ISD::AND, VT))) { // fold (zext (truncate (load x))) -> (zext (smaller load x)) // fold (zext (truncate (srl (load x), c))) -> (zext (smaller load (x+c/n))) SDValue NarrowLoad = ReduceLoadWidth(N0.getNode()); if (NarrowLoad.getNode()) { SDNode* oye = N0.getNode()->getOperand(0).getNode(); if (NarrowLoad.getNode() != N0.getNode()) { CombineTo(N0.getNode(), NarrowLoad); // CombineTo deleted the truncate, if needed, but not what's under it. AddToWorkList(oye); } return SDValue(N, 0); // Return N so it doesn't get rechecked! } SDValue Op = N0.getOperand(0); if (Op.getValueType().bitsLT(VT)) { Op = DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, Op); } else if (Op.getValueType().bitsGT(VT)) { Op = DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, Op); } return DAG.getZeroExtendInReg(Op, N->getDebugLoc(), N0.getValueType().getScalarType()); } // Fold (zext (and (trunc x), cst)) -> (and x, cst), // if either of the casts is not free. if (N0.getOpcode() == ISD::AND && N0.getOperand(0).getOpcode() == ISD::TRUNCATE && N0.getOperand(1).getOpcode() == ISD::Constant && (!TLI.isTruncateFree(N0.getOperand(0).getOperand(0).getValueType(), N0.getValueType()) || !TLI.isZExtFree(N0.getValueType(), VT))) { SDValue X = N0.getOperand(0).getOperand(0); if (X.getValueType().bitsLT(VT)) { X = DAG.getNode(ISD::ANY_EXTEND, X.getDebugLoc(), VT, X); } else if (X.getValueType().bitsGT(VT)) { X = DAG.getNode(ISD::TRUNCATE, X.getDebugLoc(), VT, X); } APInt Mask = cast(N0.getOperand(1))->getAPIntValue(); Mask = Mask.zext(VT.getSizeInBits()); return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, X, DAG.getConstant(Mask, VT)); } // fold (zext (load x)) -> (zext (truncate (zextload x))) // None of the supported targets knows how to perform load and vector_zext // on vectors in one instruction. We only perform this transformation on // scalars. if (ISD::isNON_EXTLoad(N0.getNode()) && !VT.isVector() && ((!LegalOperations && !cast(N0)->isVolatile()) || TLI.isLoadExtLegal(ISD::ZEXTLOAD, N0.getValueType()))) { bool DoXform = true; SmallVector SetCCs; if (!N0.hasOneUse()) DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::ZERO_EXTEND, SetCCs, TLI); if (DoXform) { LoadSDNode *LN0 = cast(N0); SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, N->getDebugLoc(), VT, LN0->getChain(), LN0->getBasePtr(), LN0->getPointerInfo(), N0.getValueType(), LN0->isVolatile(), LN0->isNonTemporal(), LN0->getAlignment()); CombineTo(N, ExtLoad); SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), N0.getValueType(), ExtLoad); CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1)); // Extend SetCC uses if necessary. for (unsigned i = 0, e = SetCCs.size(); i != e; ++i) { SDNode *SetCC = SetCCs[i]; SmallVector Ops; for (unsigned j = 0; j != 2; ++j) { SDValue SOp = SetCC->getOperand(j); if (SOp == Trunc) Ops.push_back(ExtLoad); else Ops.push_back(DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, SOp)); } Ops.push_back(SetCC->getOperand(2)); CombineTo(SetCC, DAG.getNode(ISD::SETCC, N->getDebugLoc(), SetCC->getValueType(0), &Ops[0], Ops.size())); } return SDValue(N, 0); // Return N so it doesn't get rechecked! } } // fold (zext (zextload x)) -> (zext (truncate (zextload x))) // fold (zext ( extload x)) -> (zext (truncate (zextload x))) if ((ISD::isZEXTLoad(N0.getNode()) || ISD::isEXTLoad(N0.getNode())) && ISD::isUNINDEXEDLoad(N0.getNode()) && N0.hasOneUse()) { LoadSDNode *LN0 = cast(N0); EVT MemVT = LN0->getMemoryVT(); if ((!LegalOperations && !LN0->isVolatile()) || TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT)) { SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, N->getDebugLoc(), VT, LN0->getChain(), LN0->getBasePtr(), LN0->getPointerInfo(), MemVT, LN0->isVolatile(), LN0->isNonTemporal(), LN0->getAlignment()); CombineTo(N, ExtLoad); CombineTo(N0.getNode(), DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), N0.getValueType(), ExtLoad), ExtLoad.getValue(1)); return SDValue(N, 0); // Return N so it doesn't get rechecked! } } if (N0.getOpcode() == ISD::SETCC) { if (!LegalOperations && VT.isVector()) { // zext(setcc) -> (and (vsetcc), (1, 1, ...) for vectors. // Only do this before legalize for now. EVT N0VT = N0.getOperand(0).getValueType(); EVT EltVT = VT.getVectorElementType(); SmallVector OneOps(VT.getVectorNumElements(), DAG.getConstant(1, EltVT)); if (VT.getSizeInBits() == N0VT.getSizeInBits()) { // We know that the # elements of the results is the same as the // # elements of the compare (and the # elements of the compare result // for that matter). Check to see that they are the same size. If so, // we know that the element size of the sext'd result matches the // element size of the compare operands. return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, DAG.getVSetCC(N->getDebugLoc(), VT, N0.getOperand(0), N0.getOperand(1), cast(N0.getOperand(2))->get()), DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), VT, &OneOps[0], OneOps.size())); } else { // If the desired elements are smaller or larger than the source // elements we can use a matching integer vector type and then // truncate/sign extend EVT MatchingElementType = EVT::getIntegerVT(*DAG.getContext(), N0VT.getScalarType().getSizeInBits()); EVT MatchingVectorType = EVT::getVectorVT(*DAG.getContext(), MatchingElementType, N0VT.getVectorNumElements()); SDValue VsetCC = DAG.getVSetCC(N->getDebugLoc(), MatchingVectorType, N0.getOperand(0), N0.getOperand(1), cast(N0.getOperand(2))->get()); return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, DAG.getSExtOrTrunc(VsetCC, N->getDebugLoc(), VT), DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), VT, &OneOps[0], OneOps.size())); } } // zext(setcc x,y,cc) -> select_cc x, y, 1, 0, cc SDValue SCC = SimplifySelectCC(N->getDebugLoc(), N0.getOperand(0), N0.getOperand(1), DAG.getConstant(1, VT), DAG.getConstant(0, VT), cast(N0.getOperand(2))->get(), true); if (SCC.getNode()) return SCC; } // (zext (shl (zext x), cst)) -> (shl (zext x), cst) if ((N0.getOpcode() == ISD::SHL || N0.getOpcode() == ISD::SRL) && isa(N0.getOperand(1)) && N0.getOperand(0).getOpcode() == ISD::ZERO_EXTEND && N0.hasOneUse()) { SDValue ShAmt = N0.getOperand(1); unsigned ShAmtVal = cast(ShAmt)->getZExtValue(); if (N0.getOpcode() == ISD::SHL) { SDValue InnerZExt = N0.getOperand(0); // If the original shl may be shifting out bits, do not perform this // transformation. unsigned KnownZeroBits = InnerZExt.getValueType().getSizeInBits() - InnerZExt.getOperand(0).getValueType().getSizeInBits(); if (ShAmtVal > KnownZeroBits) return SDValue(); } DebugLoc DL = N->getDebugLoc(); // Ensure that the shift amount is wide enough for the shifted value. if (VT.getSizeInBits() >= 256) ShAmt = DAG.getNode(ISD::ZERO_EXTEND, DL, MVT::i32, ShAmt); return DAG.getNode(N0.getOpcode(), DL, VT, DAG.getNode(ISD::ZERO_EXTEND, DL, VT, N0.getOperand(0)), ShAmt); } return SDValue(); } SDValue DAGCombiner::visitANY_EXTEND(SDNode *N) { SDValue N0 = N->getOperand(0); EVT VT = N->getValueType(0); // fold (aext c1) -> c1 if (isa(N0)) return DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, N0); // fold (aext (aext x)) -> (aext x) // fold (aext (zext x)) -> (zext x) // fold (aext (sext x)) -> (sext x) if (N0.getOpcode() == ISD::ANY_EXTEND || N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::SIGN_EXTEND) return DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT, N0.getOperand(0)); // fold (aext (truncate (load x))) -> (aext (smaller load x)) // fold (aext (truncate (srl (load x), c))) -> (aext (small load (x+c/n))) if (N0.getOpcode() == ISD::TRUNCATE) { SDValue NarrowLoad = ReduceLoadWidth(N0.getNode()); if (NarrowLoad.getNode()) { SDNode* oye = N0.getNode()->getOperand(0).getNode(); if (NarrowLoad.getNode() != N0.getNode()) { CombineTo(N0.getNode(), NarrowLoad); // CombineTo deleted the truncate, if needed, but not what's under it. AddToWorkList(oye); } return DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, NarrowLoad); } } // fold (aext (truncate x)) if (N0.getOpcode() == ISD::TRUNCATE) { SDValue TruncOp = N0.getOperand(0); if (TruncOp.getValueType() == VT) return TruncOp; // x iff x size == zext size. if (TruncOp.getValueType().bitsGT(VT)) return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, TruncOp); return DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, TruncOp); } // Fold (aext (and (trunc x), cst)) -> (and x, cst) // if the trunc is not free. if (N0.getOpcode() == ISD::AND && N0.getOperand(0).getOpcode() == ISD::TRUNCATE && N0.getOperand(1).getOpcode() == ISD::Constant && !TLI.isTruncateFree(N0.getOperand(0).getOperand(0).getValueType(), N0.getValueType())) { SDValue X = N0.getOperand(0).getOperand(0); if (X.getValueType().bitsLT(VT)) { X = DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, X); } else if (X.getValueType().bitsGT(VT)) { X = DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, X); } APInt Mask = cast(N0.getOperand(1))->getAPIntValue(); Mask = Mask.zext(VT.getSizeInBits()); return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, X, DAG.getConstant(Mask, VT)); } // fold (aext (load x)) -> (aext (truncate (extload x))) // None of the supported targets knows how to perform load and any_ext // on vectors in one instruction. We only perform this transformation on // scalars. if (ISD::isNON_EXTLoad(N0.getNode()) && !VT.isVector() && ((!LegalOperations && !cast(N0)->isVolatile()) || TLI.isLoadExtLegal(ISD::EXTLOAD, N0.getValueType()))) { bool DoXform = true; SmallVector SetCCs; if (!N0.hasOneUse()) DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::ANY_EXTEND, SetCCs, TLI); if (DoXform) { LoadSDNode *LN0 = cast(N0); SDValue ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, N->getDebugLoc(), VT, LN0->getChain(), LN0->getBasePtr(), LN0->getPointerInfo(), N0.getValueType(), LN0->isVolatile(), LN0->isNonTemporal(), LN0->getAlignment()); CombineTo(N, ExtLoad); SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), N0.getValueType(), ExtLoad); CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1)); // Extend SetCC uses if necessary. for (unsigned i = 0, e = SetCCs.size(); i != e; ++i) { SDNode *SetCC = SetCCs[i]; SmallVector Ops; for (unsigned j = 0; j != 2; ++j) { SDValue SOp = SetCC->getOperand(j); if (SOp == Trunc) Ops.push_back(ExtLoad); else Ops.push_back(DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, SOp)); } Ops.push_back(SetCC->getOperand(2)); CombineTo(SetCC, DAG.getNode(ISD::SETCC, N->getDebugLoc(), SetCC->getValueType(0), &Ops[0], Ops.size())); } return SDValue(N, 0); // Return N so it doesn't get rechecked! } } // fold (aext (zextload x)) -> (aext (truncate (zextload x))) // fold (aext (sextload x)) -> (aext (truncate (sextload x))) // fold (aext ( extload x)) -> (aext (truncate (extload x))) if (N0.getOpcode() == ISD::LOAD && !ISD::isNON_EXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) && N0.hasOneUse()) { LoadSDNode *LN0 = cast(N0); EVT MemVT = LN0->getMemoryVT(); SDValue ExtLoad = DAG.getExtLoad(LN0->getExtensionType(), N->getDebugLoc(), VT, LN0->getChain(), LN0->getBasePtr(), LN0->getPointerInfo(), MemVT, LN0->isVolatile(), LN0->isNonTemporal(), LN0->getAlignment()); CombineTo(N, ExtLoad); CombineTo(N0.getNode(), DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), N0.getValueType(), ExtLoad), ExtLoad.getValue(1)); return SDValue(N, 0); // Return N so it doesn't get rechecked! } if (N0.getOpcode() == ISD::SETCC) { // aext(setcc) -> sext_in_reg(vsetcc) for vectors. // Only do this before legalize for now. if (VT.isVector() && !LegalOperations) { EVT N0VT = N0.getOperand(0).getValueType(); // We know that the # elements of the results is the same as the // # elements of the compare (and the # elements of the compare result // for that matter). Check to see that they are the same size. If so, // we know that the element size of the sext'd result matches the // element size of the compare operands. if (VT.getSizeInBits() == N0VT.getSizeInBits()) return DAG.getVSetCC(N->getDebugLoc(), VT, N0.getOperand(0), N0.getOperand(1), cast(N0.getOperand(2))->get()); // If the desired elements are smaller or larger than the source // elements we can use a matching integer vector type and then // truncate/sign extend else { EVT MatchingElementType = EVT::getIntegerVT(*DAG.getContext(), N0VT.getScalarType().getSizeInBits()); EVT MatchingVectorType = EVT::getVectorVT(*DAG.getContext(), MatchingElementType, N0VT.getVectorNumElements()); SDValue VsetCC = DAG.getVSetCC(N->getDebugLoc(), MatchingVectorType, N0.getOperand(0), N0.getOperand(1), cast(N0.getOperand(2))->get()); return DAG.getSExtOrTrunc(VsetCC, N->getDebugLoc(), VT); } } // aext(setcc x,y,cc) -> select_cc x, y, 1, 0, cc SDValue SCC = SimplifySelectCC(N->getDebugLoc(), N0.getOperand(0), N0.getOperand(1), DAG.getConstant(1, VT), DAG.getConstant(0, VT), cast(N0.getOperand(2))->get(), true); if (SCC.getNode()) return SCC; } return SDValue(); } /// GetDemandedBits - See if the specified operand can be simplified with the /// knowledge that only the bits specified by Mask are used. If so, return the /// simpler operand, otherwise return a null SDValue. SDValue DAGCombiner::GetDemandedBits(SDValue V, const APInt &Mask) { switch (V.getOpcode()) { default: break; case ISD::OR: case ISD::XOR: // If the LHS or RHS don't contribute bits to the or, drop them. if (DAG.MaskedValueIsZero(V.getOperand(0), Mask)) return V.getOperand(1); if (DAG.MaskedValueIsZero(V.getOperand(1), Mask)) return V.getOperand(0); break; case ISD::SRL: // Only look at single-use SRLs. if (!V.getNode()->hasOneUse()) break; if (ConstantSDNode *RHSC = dyn_cast(V.getOperand(1))) { // See if we can recursively simplify the LHS. unsigned Amt = RHSC->getZExtValue(); // Watch out for shift count overflow though. if (Amt >= Mask.getBitWidth()) break; APInt NewMask = Mask << Amt; SDValue SimplifyLHS = GetDemandedBits(V.getOperand(0), NewMask); if (SimplifyLHS.getNode()) return DAG.getNode(ISD::SRL, V.getDebugLoc(), V.getValueType(), SimplifyLHS, V.getOperand(1)); } } return SDValue(); } /// ReduceLoadWidth - If the result of a wider load is shifted to right of N /// bits and then truncated to a narrower type and where N is a multiple /// of number of bits of the narrower type, transform it to a narrower load /// from address + N / num of bits of new type. If the result is to be /// extended, also fold the extension to form a extending load. SDValue DAGCombiner::ReduceLoadWidth(SDNode *N) { unsigned Opc = N->getOpcode(); ISD::LoadExtType ExtType = ISD::NON_EXTLOAD; SDValue N0 = N->getOperand(0); EVT VT = N->getValueType(0); EVT ExtVT = VT; // This transformation isn't valid for vector loads. if (VT.isVector()) return SDValue(); // Special case: SIGN_EXTEND_INREG is basically truncating to ExtVT then // extended to VT. if (Opc == ISD::SIGN_EXTEND_INREG) { ExtType = ISD::SEXTLOAD; ExtVT = cast(N->getOperand(1))->getVT(); } else if (Opc == ISD::SRL) { // Another special-case: SRL is basically zero-extending a narrower value. ExtType = ISD::ZEXTLOAD; N0 = SDValue(N, 0); ConstantSDNode *N01 = dyn_cast(N0.getOperand(1)); if (!N01) return SDValue(); ExtVT = EVT::getIntegerVT(*DAG.getContext(), VT.getSizeInBits() - N01->getZExtValue()); } if (LegalOperations && !TLI.isLoadExtLegal(ExtType, ExtVT)) return SDValue(); unsigned EVTBits = ExtVT.getSizeInBits(); // Do not generate loads of non-round integer types since these can // be expensive (and would be wrong if the type is not byte sized). if (!ExtVT.isRound()) return SDValue(); unsigned ShAmt = 0; if (N0.getOpcode() == ISD::SRL && N0.hasOneUse()) { if (ConstantSDNode *N01 = dyn_cast(N0.getOperand(1))) { ShAmt = N01->getZExtValue(); // Is the shift amount a multiple of size of VT? if ((ShAmt & (EVTBits-1)) == 0) { N0 = N0.getOperand(0); // Is the load width a multiple of size of VT? if ((N0.getValueType().getSizeInBits() & (EVTBits-1)) != 0) return SDValue(); } // At this point, we must have a load or else we can't do the transform. if (!isa(N0)) return SDValue(); // If the shift amount is larger than the input type then we're not // accessing any of the loaded bytes. If the load was a zextload/extload // then the result of the shift+trunc is zero/undef (handled elsewhere). // If the load was a sextload then the result is a splat of the sign bit // of the extended byte. This is not worth optimizing for. if (ShAmt >= cast(N0)->getMemoryVT().getSizeInBits()) return SDValue(); } } // If the load is shifted left (and the result isn't shifted back right), // we can fold the truncate through the shift. unsigned ShLeftAmt = 0; if (ShAmt == 0 && N0.getOpcode() == ISD::SHL && N0.hasOneUse() && ExtVT == VT && TLI.isNarrowingProfitable(N0.getValueType(), VT)) { if (ConstantSDNode *N01 = dyn_cast(N0.getOperand(1))) { ShLeftAmt = N01->getZExtValue(); N0 = N0.getOperand(0); } } // If we haven't found a load, we can't narrow it. Don't transform one with // multiple uses, this would require adding a new load. if (!isa(N0) || !N0.hasOneUse() || // Don't change the width of a volatile load. cast(N0)->isVolatile()) return SDValue(); // Verify that we are actually reducing a load width here. if (cast(N0)->getMemoryVT().getSizeInBits() < EVTBits) return SDValue(); LoadSDNode *LN0 = cast(N0); EVT PtrType = N0.getOperand(1).getValueType(); // For big endian targets, we need to adjust the offset to the pointer to // load the correct bytes. if (TLI.isBigEndian()) { unsigned LVTStoreBits = LN0->getMemoryVT().getStoreSizeInBits(); unsigned EVTStoreBits = ExtVT.getStoreSizeInBits(); ShAmt = LVTStoreBits - EVTStoreBits - ShAmt; } uint64_t PtrOff = ShAmt / 8; unsigned NewAlign = MinAlign(LN0->getAlignment(), PtrOff); SDValue NewPtr = DAG.getNode(ISD::ADD, LN0->getDebugLoc(), PtrType, LN0->getBasePtr(), DAG.getConstant(PtrOff, PtrType)); AddToWorkList(NewPtr.getNode()); SDValue Load; if (ExtType == ISD::NON_EXTLOAD) Load = DAG.getLoad(VT, N0.getDebugLoc(), LN0->getChain(), NewPtr, LN0->getPointerInfo().getWithOffset(PtrOff), LN0->isVolatile(), LN0->isNonTemporal(), NewAlign); else Load = DAG.getExtLoad(ExtType, N0.getDebugLoc(), VT, LN0->getChain(),NewPtr, LN0->getPointerInfo().getWithOffset(PtrOff), ExtVT, LN0->isVolatile(), LN0->isNonTemporal(), NewAlign); // Replace the old load's chain with the new load's chain. WorkListRemover DeadNodes(*this); DAG.ReplaceAllUsesOfValueWith(N0.getValue(1), Load.getValue(1), &DeadNodes); // Shift the result left, if we've swallowed a left shift. SDValue Result = Load; if (ShLeftAmt != 0) { EVT ShImmTy = getShiftAmountTy(Result.getValueType()); if (!isUIntN(ShImmTy.getSizeInBits(), ShLeftAmt)) ShImmTy = VT; Result = DAG.getNode(ISD::SHL, N0.getDebugLoc(), VT, Result, DAG.getConstant(ShLeftAmt, ShImmTy)); } // Return the new loaded value. return Result; } SDValue DAGCombiner::visitSIGN_EXTEND_INREG(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); EVT VT = N->getValueType(0); EVT EVT = cast(N1)->getVT(); unsigned VTBits = VT.getScalarType().getSizeInBits(); unsigned EVTBits = EVT.getScalarType().getSizeInBits(); // fold (sext_in_reg c1) -> c1 if (isa(N0) || N0.getOpcode() == ISD::UNDEF) return DAG.getNode(ISD::SIGN_EXTEND_INREG, N->getDebugLoc(), VT, N0, N1); // If the input is already sign extended, just drop the extension. if (DAG.ComputeNumSignBits(N0) >= VTBits-EVTBits+1) return N0; // fold (sext_in_reg (sext_in_reg x, VT2), VT1) -> (sext_in_reg x, minVT) pt2 if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG && EVT.bitsLT(cast(N0.getOperand(1))->getVT())) { return DAG.getNode(ISD::SIGN_EXTEND_INREG, N->getDebugLoc(), VT, N0.getOperand(0), N1); } // fold (sext_in_reg (sext x)) -> (sext x) // fold (sext_in_reg (aext x)) -> (sext x) // if x is small enough. if (N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND) { SDValue N00 = N0.getOperand(0); if (N00.getValueType().getScalarType().getSizeInBits() <= EVTBits && (!LegalOperations || TLI.isOperationLegal(ISD::SIGN_EXTEND, VT))) return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, N00, N1); } // fold (sext_in_reg x) -> (zext_in_reg x) if the sign bit is known zero. if (DAG.MaskedValueIsZero(N0, APInt::getBitsSet(VTBits, EVTBits-1, EVTBits))) return DAG.getZeroExtendInReg(N0, N->getDebugLoc(), EVT); // fold operands of sext_in_reg based on knowledge that the top bits are not // demanded. if (SimplifyDemandedBits(SDValue(N, 0))) return SDValue(N, 0); // fold (sext_in_reg (load x)) -> (smaller sextload x) // fold (sext_in_reg (srl (load x), c)) -> (smaller sextload (x+c/evtbits)) SDValue NarrowLoad = ReduceLoadWidth(N); if (NarrowLoad.getNode()) return NarrowLoad; // fold (sext_in_reg (srl X, 24), i8) -> (sra X, 24) // fold (sext_in_reg (srl X, 23), i8) -> (sra X, 23) iff possible. // We already fold "(sext_in_reg (srl X, 25), i8) -> srl X, 25" above. if (N0.getOpcode() == ISD::SRL) { if (ConstantSDNode *ShAmt = dyn_cast(N0.getOperand(1))) if (ShAmt->getZExtValue()+EVTBits <= VTBits) { // We can turn this into an SRA iff the input to the SRL is already sign // extended enough. unsigned InSignBits = DAG.ComputeNumSignBits(N0.getOperand(0)); if (VTBits-(ShAmt->getZExtValue()+EVTBits) < InSignBits) return DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, N0.getOperand(0), N0.getOperand(1)); } } // fold (sext_inreg (extload x)) -> (sextload x) if (ISD::isEXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) && EVT == cast(N0)->getMemoryVT() && ((!LegalOperations && !cast(N0)->isVolatile()) || TLI.isLoadExtLegal(ISD::SEXTLOAD, EVT))) { LoadSDNode *LN0 = cast(N0); SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, N->getDebugLoc(), VT, LN0->getChain(), LN0->getBasePtr(), LN0->getPointerInfo(), EVT, LN0->isVolatile(), LN0->isNonTemporal(), LN0->getAlignment()); CombineTo(N, ExtLoad); CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1)); return SDValue(N, 0); // Return N so it doesn't get rechecked! } // fold (sext_inreg (zextload x)) -> (sextload x) iff load has one use if (ISD::isZEXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) && N0.hasOneUse() && EVT == cast(N0)->getMemoryVT() && ((!LegalOperations && !cast(N0)->isVolatile()) || TLI.isLoadExtLegal(ISD::SEXTLOAD, EVT))) { LoadSDNode *LN0 = cast(N0); SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, N->getDebugLoc(), VT, LN0->getChain(), LN0->getBasePtr(), LN0->getPointerInfo(), EVT, LN0->isVolatile(), LN0->isNonTemporal(), LN0->getAlignment()); CombineTo(N, ExtLoad); CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1)); return SDValue(N, 0); // Return N so it doesn't get rechecked! } return SDValue(); } SDValue DAGCombiner::visitTRUNCATE(SDNode *N) { SDValue N0 = N->getOperand(0); EVT VT = N->getValueType(0); // noop truncate if (N0.getValueType() == N->getValueType(0)) return N0; // fold (truncate c1) -> c1 if (isa(N0)) return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, N0); // fold (truncate (truncate x)) -> (truncate x) if (N0.getOpcode() == ISD::TRUNCATE) return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, N0.getOperand(0)); // fold (truncate (ext x)) -> (ext x) or (truncate x) or x if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND) { if (N0.getOperand(0).getValueType().bitsLT(VT)) // if the source is smaller than the dest, we still need an extend return DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT, N0.getOperand(0)); else if (N0.getOperand(0).getValueType().bitsGT(VT)) // if the source is larger than the dest, than we just need the truncate return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, N0.getOperand(0)); else // if the source and dest are the same type, we can drop both the extend // and the truncate. return N0.getOperand(0); } // See if we can simplify the input to this truncate through knowledge that // only the low bits are being used. // For example "trunc (or (shl x, 8), y)" // -> trunc y // Currently we only perform this optimization on scalars because vectors // may have different active low bits. if (!VT.isVector()) { SDValue Shorter = GetDemandedBits(N0, APInt::getLowBitsSet(N0.getValueSizeInBits(), VT.getSizeInBits())); if (Shorter.getNode()) return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, Shorter); } // fold (truncate (load x)) -> (smaller load x) // fold (truncate (srl (load x), c)) -> (smaller load (x+c/evtbits)) if (!LegalTypes || TLI.isTypeDesirableForOp(N0.getOpcode(), VT)) { SDValue Reduced = ReduceLoadWidth(N); if (Reduced.getNode()) return Reduced; } // Simplify the operands using demanded-bits information. if (!VT.isVector() && SimplifyDemandedBits(SDValue(N, 0))) return SDValue(N, 0); return SDValue(); } static SDNode *getBuildPairElt(SDNode *N, unsigned i) { SDValue Elt = N->getOperand(i); if (Elt.getOpcode() != ISD::MERGE_VALUES) return Elt.getNode(); return Elt.getOperand(Elt.getResNo()).getNode(); } /// CombineConsecutiveLoads - build_pair (load, load) -> load /// if load locations are consecutive. SDValue DAGCombiner::CombineConsecutiveLoads(SDNode *N, EVT VT) { assert(N->getOpcode() == ISD::BUILD_PAIR); LoadSDNode *LD1 = dyn_cast(getBuildPairElt(N, 0)); LoadSDNode *LD2 = dyn_cast(getBuildPairElt(N, 1)); if (!LD1 || !LD2 || !ISD::isNON_EXTLoad(LD1) || !LD1->hasOneUse() || LD1->getPointerInfo().getAddrSpace() != LD2->getPointerInfo().getAddrSpace()) return SDValue(); EVT LD1VT = LD1->getValueType(0); if (ISD::isNON_EXTLoad(LD2) && LD2->hasOneUse() && // If both are volatile this would reduce the number of volatile loads. // If one is volatile it might be ok, but play conservative and bail out. !LD1->isVolatile() && !LD2->isVolatile() && DAG.isConsecutiveLoad(LD2, LD1, LD1VT.getSizeInBits()/8, 1)) { unsigned Align = LD1->getAlignment(); unsigned NewAlign = TLI.getTargetData()-> getABITypeAlignment(VT.getTypeForEVT(*DAG.getContext())); if (NewAlign <= Align && (!LegalOperations || TLI.isOperationLegal(ISD::LOAD, VT))) return DAG.getLoad(VT, N->getDebugLoc(), LD1->getChain(), LD1->getBasePtr(), LD1->getPointerInfo(), false, false, Align); } return SDValue(); } SDValue DAGCombiner::visitBITCAST(SDNode *N) { SDValue N0 = N->getOperand(0); EVT VT = N->getValueType(0); // If the input is a BUILD_VECTOR with all constant elements, fold this now. // Only do this before legalize, since afterward the target may be depending // on the bitconvert. // First check to see if this is all constant. if (!LegalTypes && N0.getOpcode() == ISD::BUILD_VECTOR && N0.getNode()->hasOneUse() && VT.isVector()) { bool isSimple = true; for (unsigned i = 0, e = N0.getNumOperands(); i != e; ++i) if (N0.getOperand(i).getOpcode() != ISD::UNDEF && N0.getOperand(i).getOpcode() != ISD::Constant && N0.getOperand(i).getOpcode() != ISD::ConstantFP) { isSimple = false; break; } EVT DestEltVT = N->getValueType(0).getVectorElementType(); assert(!DestEltVT.isVector() && "Element type of vector ValueType must not be vector!"); if (isSimple) return ConstantFoldBITCASTofBUILD_VECTOR(N0.getNode(), DestEltVT); } // If the input is a constant, let getNode fold it. if (isa(N0) || isa(N0)) { SDValue Res = DAG.getNode(ISD::BITCAST, N->getDebugLoc(), VT, N0); if (Res.getNode() != N) { if (!LegalOperations || TLI.isOperationLegal(Res.getNode()->getOpcode(), VT)) return Res; // Folding it resulted in an illegal node, and it's too late to // do that. Clean up the old node and forego the transformation. // Ideally this won't happen very often, because instcombine // and the earlier dagcombine runs (where illegal nodes are // permitted) should have folded most of them already. DAG.DeleteNode(Res.getNode()); } } // (conv (conv x, t1), t2) -> (conv x, t2) if (N0.getOpcode() == ISD::BITCAST) return DAG.getNode(ISD::BITCAST, N->getDebugLoc(), VT, N0.getOperand(0)); // fold (conv (load x)) -> (load (conv*)x) // If the resultant load doesn't need a higher alignment than the original! if (ISD::isNormalLoad(N0.getNode()) && N0.hasOneUse() && // Do not change the width of a volatile load. !cast(N0)->isVolatile() && (!LegalOperations || TLI.isOperationLegal(ISD::LOAD, VT))) { LoadSDNode *LN0 = cast(N0); unsigned Align = TLI.getTargetData()-> getABITypeAlignment(VT.getTypeForEVT(*DAG.getContext())); unsigned OrigAlign = LN0->getAlignment(); if (Align <= OrigAlign) { SDValue Load = DAG.getLoad(VT, N->getDebugLoc(), LN0->getChain(), LN0->getBasePtr(), LN0->getPointerInfo(), LN0->isVolatile(), LN0->isNonTemporal(), OrigAlign); AddToWorkList(N); CombineTo(N0.getNode(), DAG.getNode(ISD::BITCAST, N0.getDebugLoc(), N0.getValueType(), Load), Load.getValue(1)); return Load; } } // fold (bitconvert (fneg x)) -> (xor (bitconvert x), signbit) // fold (bitconvert (fabs x)) -> (and (bitconvert x), (not signbit)) // This often reduces constant pool loads. if ((N0.getOpcode() == ISD::FNEG || N0.getOpcode() == ISD::FABS) && N0.getNode()->hasOneUse() && VT.isInteger() && !VT.isVector()) { SDValue NewConv = DAG.getNode(ISD::BITCAST, N0.getDebugLoc(), VT, N0.getOperand(0)); AddToWorkList(NewConv.getNode()); APInt SignBit = APInt::getSignBit(VT.getSizeInBits()); if (N0.getOpcode() == ISD::FNEG) return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, NewConv, DAG.getConstant(SignBit, VT)); assert(N0.getOpcode() == ISD::FABS); return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, NewConv, DAG.getConstant(~SignBit, VT)); } // fold (bitconvert (fcopysign cst, x)) -> // (or (and (bitconvert x), sign), (and cst, (not sign))) // Note that we don't handle (copysign x, cst) because this can always be // folded to an fneg or fabs. if (N0.getOpcode() == ISD::FCOPYSIGN && N0.getNode()->hasOneUse() && isa(N0.getOperand(0)) && VT.isInteger() && !VT.isVector()) { unsigned OrigXWidth = N0.getOperand(1).getValueType().getSizeInBits(); EVT IntXVT = EVT::getIntegerVT(*DAG.getContext(), OrigXWidth); if (isTypeLegal(IntXVT)) { SDValue X = DAG.getNode(ISD::BITCAST, N0.getDebugLoc(), IntXVT, N0.getOperand(1)); AddToWorkList(X.getNode()); // If X has a different width than the result/lhs, sext it or truncate it. unsigned VTWidth = VT.getSizeInBits(); if (OrigXWidth < VTWidth) { X = DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, X); AddToWorkList(X.getNode()); } else if (OrigXWidth > VTWidth) { // To get the sign bit in the right place, we have to shift it right // before truncating. X = DAG.getNode(ISD::SRL, X.getDebugLoc(), X.getValueType(), X, DAG.getConstant(OrigXWidth-VTWidth, X.getValueType())); AddToWorkList(X.getNode()); X = DAG.getNode(ISD::TRUNCATE, X.getDebugLoc(), VT, X); AddToWorkList(X.getNode()); } APInt SignBit = APInt::getSignBit(VT.getSizeInBits()); X = DAG.getNode(ISD::AND, X.getDebugLoc(), VT, X, DAG.getConstant(SignBit, VT)); AddToWorkList(X.getNode()); SDValue Cst = DAG.getNode(ISD::BITCAST, N0.getDebugLoc(), VT, N0.getOperand(0)); Cst = DAG.getNode(ISD::AND, Cst.getDebugLoc(), VT, Cst, DAG.getConstant(~SignBit, VT)); AddToWorkList(Cst.getNode()); return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, X, Cst); } } // bitconvert(build_pair(ld, ld)) -> ld iff load locations are consecutive. if (N0.getOpcode() == ISD::BUILD_PAIR) { SDValue CombineLD = CombineConsecutiveLoads(N0.getNode(), VT); if (CombineLD.getNode()) return CombineLD; } return SDValue(); } SDValue DAGCombiner::visitBUILD_PAIR(SDNode *N) { EVT VT = N->getValueType(0); return CombineConsecutiveLoads(N, VT); } /// ConstantFoldBITCASTofBUILD_VECTOR - We know that BV is a build_vector /// node with Constant, ConstantFP or Undef operands. DstEltVT indicates the /// destination element value type. SDValue DAGCombiner:: ConstantFoldBITCASTofBUILD_VECTOR(SDNode *BV, EVT DstEltVT) { EVT SrcEltVT = BV->getValueType(0).getVectorElementType(); // If this is already the right type, we're done. if (SrcEltVT == DstEltVT) return SDValue(BV, 0); unsigned SrcBitSize = SrcEltVT.getSizeInBits(); unsigned DstBitSize = DstEltVT.getSizeInBits(); // If this is a conversion of N elements of one type to N elements of another // type, convert each element. This handles FP<->INT cases. if (SrcBitSize == DstBitSize) { EVT VT = EVT::getVectorVT(*DAG.getContext(), DstEltVT, BV->getValueType(0).getVectorNumElements()); // Due to the FP element handling below calling this routine recursively, // we can end up with a scalar-to-vector node here. if (BV->getOpcode() == ISD::SCALAR_TO_VECTOR) return DAG.getNode(ISD::SCALAR_TO_VECTOR, BV->getDebugLoc(), VT, DAG.getNode(ISD::BITCAST, BV->getDebugLoc(), DstEltVT, BV->getOperand(0))); SmallVector Ops; for (unsigned i = 0, e = BV->getNumOperands(); i != e; ++i) { SDValue Op = BV->getOperand(i); // If the vector element type is not legal, the BUILD_VECTOR operands // are promoted and implicitly truncated. Make that explicit here. if (Op.getValueType() != SrcEltVT) Op = DAG.getNode(ISD::TRUNCATE, BV->getDebugLoc(), SrcEltVT, Op); Ops.push_back(DAG.getNode(ISD::BITCAST, BV->getDebugLoc(), DstEltVT, Op)); AddToWorkList(Ops.back().getNode()); } return DAG.getNode(ISD::BUILD_VECTOR, BV->getDebugLoc(), VT, &Ops[0], Ops.size()); } // Otherwise, we're growing or shrinking the elements. To avoid having to // handle annoying details of growing/shrinking FP values, we convert them to // int first. if (SrcEltVT.isFloatingPoint()) { // Convert the input float vector to a int vector where the elements are the // same sizes. assert((SrcEltVT == MVT::f32 || SrcEltVT == MVT::f64) && "Unknown FP VT!"); EVT IntVT = EVT::getIntegerVT(*DAG.getContext(), SrcEltVT.getSizeInBits()); BV = ConstantFoldBITCASTofBUILD_VECTOR(BV, IntVT).getNode(); SrcEltVT = IntVT; } // Now we know the input is an integer vector. If the output is a FP type, // convert to integer first, then to FP of the right size. if (DstEltVT.isFloatingPoint()) { assert((DstEltVT == MVT::f32 || DstEltVT == MVT::f64) && "Unknown FP VT!"); EVT TmpVT = EVT::getIntegerVT(*DAG.getContext(), DstEltVT.getSizeInBits()); SDNode *Tmp = ConstantFoldBITCASTofBUILD_VECTOR(BV, TmpVT).getNode(); // Next, convert to FP elements of the same size. return ConstantFoldBITCASTofBUILD_VECTOR(Tmp, DstEltVT); } // Okay, we know the src/dst types are both integers of differing types. // Handling growing first. assert(SrcEltVT.isInteger() && DstEltVT.isInteger()); if (SrcBitSize < DstBitSize) { unsigned NumInputsPerOutput = DstBitSize/SrcBitSize; SmallVector Ops; for (unsigned i = 0, e = BV->getNumOperands(); i != e; i += NumInputsPerOutput) { bool isLE = TLI.isLittleEndian(); APInt NewBits = APInt(DstBitSize, 0); bool EltIsUndef = true; for (unsigned j = 0; j != NumInputsPerOutput; ++j) { // Shift the previously computed bits over. NewBits <<= SrcBitSize; SDValue Op = BV->getOperand(i+ (isLE ? (NumInputsPerOutput-j-1) : j)); if (Op.getOpcode() == ISD::UNDEF) continue; EltIsUndef = false; NewBits |= cast(Op)->getAPIntValue(). zextOrTrunc(SrcBitSize).zext(DstBitSize); } if (EltIsUndef) Ops.push_back(DAG.getUNDEF(DstEltVT)); else Ops.push_back(DAG.getConstant(NewBits, DstEltVT)); } EVT VT = EVT::getVectorVT(*DAG.getContext(), DstEltVT, Ops.size()); return DAG.getNode(ISD::BUILD_VECTOR, BV->getDebugLoc(), VT, &Ops[0], Ops.size()); } // Finally, this must be the case where we are shrinking elements: each input // turns into multiple outputs. bool isS2V = ISD::isScalarToVector(BV); unsigned NumOutputsPerInput = SrcBitSize/DstBitSize; EVT VT = EVT::getVectorVT(*DAG.getContext(), DstEltVT, NumOutputsPerInput*BV->getNumOperands()); SmallVector Ops; for (unsigned i = 0, e = BV->getNumOperands(); i != e; ++i) { if (BV->getOperand(i).getOpcode() == ISD::UNDEF) { for (unsigned j = 0; j != NumOutputsPerInput; ++j) Ops.push_back(DAG.getUNDEF(DstEltVT)); continue; } APInt OpVal = cast(BV->getOperand(i))-> getAPIntValue().zextOrTrunc(SrcBitSize); for (unsigned j = 0; j != NumOutputsPerInput; ++j) { APInt ThisVal = OpVal.trunc(DstBitSize); Ops.push_back(DAG.getConstant(ThisVal, DstEltVT)); if (isS2V && i == 0 && j == 0 && ThisVal.zext(SrcBitSize) == OpVal) // Simply turn this into a SCALAR_TO_VECTOR of the new type. return DAG.getNode(ISD::SCALAR_TO_VECTOR, BV->getDebugLoc(), VT, Ops[0]); OpVal = OpVal.lshr(DstBitSize); } // For big endian targets, swap the order of the pieces of each element. if (TLI.isBigEndian()) std::reverse(Ops.end()-NumOutputsPerInput, Ops.end()); } return DAG.getNode(ISD::BUILD_VECTOR, BV->getDebugLoc(), VT, &Ops[0], Ops.size()); } SDValue DAGCombiner::visitFADD(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); ConstantFPSDNode *N0CFP = dyn_cast(N0); ConstantFPSDNode *N1CFP = dyn_cast(N1); EVT VT = N->getValueType(0); // fold vector ops if (VT.isVector()) { SDValue FoldedVOp = SimplifyVBinOp(N); if (FoldedVOp.getNode()) return FoldedVOp; } // fold (fadd c1, c2) -> (fadd c1, c2) if (N0CFP && N1CFP && VT != MVT::ppcf128) return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0, N1); // canonicalize constant to RHS if (N0CFP && !N1CFP) return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N1, N0); // fold (fadd A, 0) -> A if (UnsafeFPMath && N1CFP && N1CFP->getValueAPF().isZero()) return N0; // fold (fadd A, (fneg B)) -> (fsub A, B) if (isNegatibleForFree(N1, LegalOperations) == 2) return DAG.getNode(ISD::FSUB, N->getDebugLoc(), VT, N0, GetNegatedExpression(N1, DAG, LegalOperations)); // fold (fadd (fneg A), B) -> (fsub B, A) if (isNegatibleForFree(N0, LegalOperations) == 2) return DAG.getNode(ISD::FSUB, N->getDebugLoc(), VT, N1, GetNegatedExpression(N0, DAG, LegalOperations)); // If allowed, fold (fadd (fadd x, c1), c2) -> (fadd x, (fadd c1, c2)) if (UnsafeFPMath && N1CFP && N0.getOpcode() == ISD::FADD && N0.getNode()->hasOneUse() && isa(N0.getOperand(1))) return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0.getOperand(0), DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0.getOperand(1), N1)); return SDValue(); } SDValue DAGCombiner::visitFSUB(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); ConstantFPSDNode *N0CFP = dyn_cast(N0); ConstantFPSDNode *N1CFP = dyn_cast(N1); EVT VT = N->getValueType(0); // fold vector ops if (VT.isVector()) { SDValue FoldedVOp = SimplifyVBinOp(N); if (FoldedVOp.getNode()) return FoldedVOp; } // fold (fsub c1, c2) -> c1-c2 if (N0CFP && N1CFP && VT != MVT::ppcf128) return DAG.getNode(ISD::FSUB, N->getDebugLoc(), VT, N0, N1); // fold (fsub A, 0) -> A if (UnsafeFPMath && N1CFP && N1CFP->getValueAPF().isZero()) return N0; // fold (fsub 0, B) -> -B if (UnsafeFPMath && N0CFP && N0CFP->getValueAPF().isZero()) { if (isNegatibleForFree(N1, LegalOperations)) return GetNegatedExpression(N1, DAG, LegalOperations); if (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT)) return DAG.getNode(ISD::FNEG, N->getDebugLoc(), VT, N1); } // fold (fsub A, (fneg B)) -> (fadd A, B) if (isNegatibleForFree(N1, LegalOperations)) return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0, GetNegatedExpression(N1, DAG, LegalOperations)); return SDValue(); } SDValue DAGCombiner::visitFMUL(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); ConstantFPSDNode *N0CFP = dyn_cast(N0); ConstantFPSDNode *N1CFP = dyn_cast(N1); EVT VT = N->getValueType(0); // fold vector ops if (VT.isVector()) { SDValue FoldedVOp = SimplifyVBinOp(N); if (FoldedVOp.getNode()) return FoldedVOp; } // fold (fmul c1, c2) -> c1*c2 if (N0CFP && N1CFP && VT != MVT::ppcf128) return DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT, N0, N1); // canonicalize constant to RHS if (N0CFP && !N1CFP) return DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT, N1, N0); // fold (fmul A, 0) -> 0 if (UnsafeFPMath && N1CFP && N1CFP->getValueAPF().isZero()) return N1; // fold (fmul A, 0) -> 0, vector edition. if (UnsafeFPMath && ISD::isBuildVectorAllZeros(N1.getNode())) return N1; // fold (fmul X, 2.0) -> (fadd X, X) if (N1CFP && N1CFP->isExactlyValue(+2.0)) return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0, N0); // fold (fmul X, -1.0) -> (fneg X) if (N1CFP && N1CFP->isExactlyValue(-1.0)) if (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT)) return DAG.getNode(ISD::FNEG, N->getDebugLoc(), VT, N0); // fold (fmul (fneg X), (fneg Y)) -> (fmul X, Y) if (char LHSNeg = isNegatibleForFree(N0, LegalOperations)) { if (char RHSNeg = isNegatibleForFree(N1, LegalOperations)) { // Both can be negated for free, check to see if at least one is cheaper // negated. if (LHSNeg == 2 || RHSNeg == 2) return DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT, GetNegatedExpression(N0, DAG, LegalOperations), GetNegatedExpression(N1, DAG, LegalOperations)); } } // If allowed, fold (fmul (fmul x, c1), c2) -> (fmul x, (fmul c1, c2)) if (UnsafeFPMath && N1CFP && N0.getOpcode() == ISD::FMUL && N0.getNode()->hasOneUse() && isa(N0.getOperand(1))) return DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT, N0.getOperand(0), DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT, N0.getOperand(1), N1)); return SDValue(); } SDValue DAGCombiner::visitFDIV(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); ConstantFPSDNode *N0CFP = dyn_cast(N0); ConstantFPSDNode *N1CFP = dyn_cast(N1); EVT VT = N->getValueType(0); // fold vector ops if (VT.isVector()) { SDValue FoldedVOp = SimplifyVBinOp(N); if (FoldedVOp.getNode()) return FoldedVOp; } // fold (fdiv c1, c2) -> c1/c2 if (N0CFP && N1CFP && VT != MVT::ppcf128) return DAG.getNode(ISD::FDIV, N->getDebugLoc(), VT, N0, N1); // (fdiv (fneg X), (fneg Y)) -> (fdiv X, Y) if (char LHSNeg = isNegatibleForFree(N0, LegalOperations)) { if (char RHSNeg = isNegatibleForFree(N1, LegalOperations)) { // Both can be negated for free, check to see if at least one is cheaper // negated. if (LHSNeg == 2 || RHSNeg == 2) return DAG.getNode(ISD::FDIV, N->getDebugLoc(), VT, GetNegatedExpression(N0, DAG, LegalOperations), GetNegatedExpression(N1, DAG, LegalOperations)); } } return SDValue(); } SDValue DAGCombiner::visitFREM(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); ConstantFPSDNode *N0CFP = dyn_cast(N0); ConstantFPSDNode *N1CFP = dyn_cast(N1); EVT VT = N->getValueType(0); // fold (frem c1, c2) -> fmod(c1,c2) if (N0CFP && N1CFP && VT != MVT::ppcf128) return DAG.getNode(ISD::FREM, N->getDebugLoc(), VT, N0, N1); return SDValue(); } SDValue DAGCombiner::visitFCOPYSIGN(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); ConstantFPSDNode *N0CFP = dyn_cast(N0); ConstantFPSDNode *N1CFP = dyn_cast(N1); EVT VT = N->getValueType(0); if (N0CFP && N1CFP && VT != MVT::ppcf128) // Constant fold return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT, N0, N1); if (N1CFP) { const APFloat& V = N1CFP->getValueAPF(); // copysign(x, c1) -> fabs(x) iff ispos(c1) // copysign(x, c1) -> fneg(fabs(x)) iff isneg(c1) if (!V.isNegative()) { if (!LegalOperations || TLI.isOperationLegal(ISD::FABS, VT)) return DAG.getNode(ISD::FABS, N->getDebugLoc(), VT, N0); } else { if (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT)) return DAG.getNode(ISD::FNEG, N->getDebugLoc(), VT, DAG.getNode(ISD::FABS, N0.getDebugLoc(), VT, N0)); } } // copysign(fabs(x), y) -> copysign(x, y) // copysign(fneg(x), y) -> copysign(x, y) // copysign(copysign(x,z), y) -> copysign(x, y) if (N0.getOpcode() == ISD::FABS || N0.getOpcode() == ISD::FNEG || N0.getOpcode() == ISD::FCOPYSIGN) return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT, N0.getOperand(0), N1); // copysign(x, abs(y)) -> abs(x) if (N1.getOpcode() == ISD::FABS) return DAG.getNode(ISD::FABS, N->getDebugLoc(), VT, N0); // copysign(x, copysign(y,z)) -> copysign(x, z) if (N1.getOpcode() == ISD::FCOPYSIGN) return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT, N0, N1.getOperand(1)); // copysign(x, fp_extend(y)) -> copysign(x, y) // copysign(x, fp_round(y)) -> copysign(x, y) if (N1.getOpcode() == ISD::FP_EXTEND || N1.getOpcode() == ISD::FP_ROUND) return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT, N0, N1.getOperand(0)); return SDValue(); } SDValue DAGCombiner::visitSINT_TO_FP(SDNode *N) { SDValue N0 = N->getOperand(0); ConstantSDNode *N0C = dyn_cast(N0); EVT VT = N->getValueType(0); EVT OpVT = N0.getValueType(); // fold (sint_to_fp c1) -> c1fp if (N0C && OpVT != MVT::ppcf128 && // ...but only if the target supports immediate floating-point values (Level == llvm::Unrestricted || TLI.isOperationLegalOrCustom(llvm::ISD::ConstantFP, VT))) return DAG.getNode(ISD::SINT_TO_FP, N->getDebugLoc(), VT, N0); // If the input is a legal type, and SINT_TO_FP is not legal on this target, // but UINT_TO_FP is legal on this target, try to convert. if (!TLI.isOperationLegalOrCustom(ISD::SINT_TO_FP, OpVT) && TLI.isOperationLegalOrCustom(ISD::UINT_TO_FP, OpVT)) { // If the sign bit is known to be zero, we can change this to UINT_TO_FP. if (DAG.SignBitIsZero(N0)) return DAG.getNode(ISD::UINT_TO_FP, N->getDebugLoc(), VT, N0); } return SDValue(); } SDValue DAGCombiner::visitUINT_TO_FP(SDNode *N) { SDValue N0 = N->getOperand(0); ConstantSDNode *N0C = dyn_cast(N0); EVT VT = N->getValueType(0); EVT OpVT = N0.getValueType(); // fold (uint_to_fp c1) -> c1fp if (N0C && OpVT != MVT::ppcf128 && // ...but only if the target supports immediate floating-point values (Level == llvm::Unrestricted || TLI.isOperationLegalOrCustom(llvm::ISD::ConstantFP, VT))) return DAG.getNode(ISD::UINT_TO_FP, N->getDebugLoc(), VT, N0); // If the input is a legal type, and UINT_TO_FP is not legal on this target, // but SINT_TO_FP is legal on this target, try to convert. if (!TLI.isOperationLegalOrCustom(ISD::UINT_TO_FP, OpVT) && TLI.isOperationLegalOrCustom(ISD::SINT_TO_FP, OpVT)) { // If the sign bit is known to be zero, we can change this to SINT_TO_FP. if (DAG.SignBitIsZero(N0)) return DAG.getNode(ISD::SINT_TO_FP, N->getDebugLoc(), VT, N0); } return SDValue(); } SDValue DAGCombiner::visitFP_TO_SINT(SDNode *N) { SDValue N0 = N->getOperand(0); ConstantFPSDNode *N0CFP = dyn_cast(N0); EVT VT = N->getValueType(0); // fold (fp_to_sint c1fp) -> c1 if (N0CFP) return DAG.getNode(ISD::FP_TO_SINT, N->getDebugLoc(), VT, N0); return SDValue(); } SDValue DAGCombiner::visitFP_TO_UINT(SDNode *N) { SDValue N0 = N->getOperand(0); ConstantFPSDNode *N0CFP = dyn_cast(N0); EVT VT = N->getValueType(0); // fold (fp_to_uint c1fp) -> c1 if (N0CFP && VT != MVT::ppcf128) return DAG.getNode(ISD::FP_TO_UINT, N->getDebugLoc(), VT, N0); return SDValue(); } SDValue DAGCombiner::visitFP_ROUND(SDNode *N) { SDValue N0 = N->getOperand(0); SDValue N1 = N->getOperand(1); ConstantFPSDNode *N0CFP = dyn_cast(N0); EVT VT = N->getValueType(0); // fold (fp_round c1fp) -> c1fp if (N0CFP && N0.getValueType() != MVT::ppcf128) return DAG.getNode(ISD::FP_ROUND, N->getDebugLoc(), VT, N0, N1); // fold (fp_round (fp_extend x)) -> x if (N0.getOpcode() == ISD::FP_EXTEND && VT == N0.getOperand(0).getValueType()) return N0.getOperand(0); // fold (fp_round (fp_round x)) -> (fp_round x) if (N0.getOpcode() == ISD::FP_ROUND) { // This is a value preserving truncation if both round's are. bool IsTrunc = N->getConstantOperandVal(1) == 1 && N0.getNode()->getConstantOperandVal(1) == 1; return DAG.getNode(ISD::FP_ROUND, N->getDebugLoc(), VT, N0.getOperand(0), DAG.getIntPtrConstant(IsTrunc)); } // fold (fp_round (copysign X, Y)) -> (copysign (fp_round X), Y) if (N0.getOpcode() == ISD::FCOPYSIGN && N0.getNode()->hasOneUse()) { SDValue Tmp = DAG.getNode(ISD::FP_ROUND, N0.getDebugLoc(), VT, N0.getOperand(0), N1); AddToWorkList(Tmp.getNode()); return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT, Tmp, N0.getOperand(1)); } return SDValue(); } SDValue DAGCombiner::visitFP_ROUND_INREG(SDNode *N) { SDValue N0 = N->getOperand(0); EVT VT = N->getValueType(0); EVT EVT = cast(N->getOperand(1))->getVT(); ConstantFPSDNode *N0CFP = dyn_cast(N0); // fold (fp_round_inreg c1fp) -> c1fp if (N0CFP && isTypeLegal(EVT)) { SDValue Round = DAG.getConstantFP(*N0CFP->getConstantFPValue(), EVT); return DAG.getNode(ISD::FP_EXTEND, N->getDebugLoc(), VT, Round); } return SDValue(); } SDValue DAGCombiner::visitFP_EXTEND(SDNode *N) { SDValue N0 = N->getOperand(0); ConstantFPSDNode *N0CFP = dyn_cast(N0); EVT VT = N->getValueType(0); // If this is fp_round(fpextend), don't fold it, allow ourselves to be folded. if (N->hasOneUse() && N->use_begin()->getOpcode() == ISD::FP_ROUND) return SDValue(); // fold (fp_extend c1fp) -> c1fp if (N0CFP && VT != MVT::ppcf128) return DAG.getNode(ISD::FP_EXTEND, N->getDebugLoc(), VT, N0); // Turn fp_extend(fp_round(X, 1)) -> x since the fp_round doesn't affect the // value of X. if (N0.getOpcode() == ISD::FP_ROUND && N0.getNode()->getConstantOperandVal(1) == 1) { SDValue In = N0.getOperand(0); if (In.getValueType() == VT) return In; if (VT.bitsLT(In.getValueType())) return DAG.getNode(ISD::FP_ROUND, N->getDebugLoc(), VT, In, N0.getOperand(1)); return DAG.getNode(ISD::FP_EXTEND, N->getDebugLoc(), VT, In); } // fold (fpext (load x)) -> (fpext (fptrunc (extload x))) if (ISD::isNON_EXTLoad(N0.getNode()) && N0.hasOneUse() && ((!LegalOperations && !cast(N0)->isVolatile()) || TLI.isLoadExtLegal(ISD::EXTLOAD, N0.getValueType()))) { LoadSDNode *LN0 = cast(N0); SDValue ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, N->getDebugLoc(), VT, LN0->getChain(), LN0->getBasePtr(), LN0->getPointerInfo(), N0.getValueType(), LN0->isVolatile(), LN0->isNonTemporal(), LN0->getAlignment()); CombineTo(N, ExtLoad); CombineTo(N0.getNode(), DAG.getNode(ISD::FP_ROUND, N0.getDebugLoc(), N0.getValueType(), ExtLoad, DAG.getIntPtrConstant(1)), ExtLoad.getValue(1)); return SDValue(N, 0); // Return N so it doesn't get rechecked! } return SDValue(); } SDValue DAGCombiner::visitFNEG(SDNode *N) { SDValue N0 = N->getOperand(0); EVT VT = N->getValueType(0); if (isNegatibleForFree(N0, LegalOperations)) return GetNegatedExpression(N0, DAG, LegalOperations); // Transform fneg(bitconvert(x)) -> bitconvert(x^sign) to avoid loading // constant pool values. if (N0.getOpcode() == ISD::BITCAST && !VT.isVector() && N0.getNode()->hasOneUse() && N0.getOperand(0).getValueType().isInteger()) { SDValue Int = N0.getOperand(0); EVT IntVT = Int.getValueType(); if (IntVT.isInteger() && !IntVT.isVector()) { Int = DAG.getNode(ISD::XOR, N0.getDebugLoc(), IntVT, Int, DAG.getConstant(APInt::getSignBit(IntVT.getSizeInBits()), IntVT)); AddToWorkList(Int.getNode()); return DAG.getNode(ISD::BITCAST, N->getDebugLoc(), VT, Int); } } return SDValue(); } SDValue DAGCombiner::visitFABS(SDNode *N) { SDValue N0 = N->getOperand(0); ConstantFPSDNode *N0CFP = dyn_cast(N0); EVT VT = N->getValueType(0); // fold (fabs c1) -> fabs(c1) if (N0CFP && VT != MVT::ppcf128) return DAG.getNode(ISD::FABS, N->getDebugLoc(), VT, N0); // fold (fabs (fabs x)) -> (fabs x) if (N0.getOpcode() == ISD::FABS) return N->getOperand(0); // fold (fabs (fneg x)) -> (fabs x) // fold (fabs (fcopysign x, y)) -> (fabs x) if (N0.getOpcode() == ISD::FNEG || N0.getOpcode() == ISD::FCOPYSIGN) return DAG.getNode(ISD::FABS, N->getDebugLoc(), VT, N0.getOperand(0)); // Transform fabs(bitconvert(x)) -> bitconvert(x&~sign) to avoid loading // constant pool values. if (N0.getOpcode() == ISD::BITCAST && N0.getNode()->hasOneUse() && N0.getOperand(0).getValueType().isInteger() && !N0.getOperand(0).getValueType().isVector()) { SDValue Int = N0.getOperand(0); EVT IntVT = Int.getValueType(); if (IntVT.isInteger() && !IntVT.isVector()) { Int = DAG.getNode(ISD::AND, N0.getDebugLoc(), IntVT, Int, DAG.getConstant(~APInt::getSignBit(IntVT.getSizeInBits()), IntVT)); AddToWorkList(Int.getNode()); return DAG.getNode(ISD::BITCAST, N->getDebugLoc(), N->getValueType(0), Int); } } return SDValue(); } SDValue DAGCombiner::visitBRCOND(SDNode *N) { SDValue Chain = N->getOperand(0); SDValue N1 = N->getOperand(1); SDValue N2 = N->getOperand(2); // If N is a constant we could fold this into a fallthrough or unconditional // branch. However that doesn't happen very often in normal code, because // Instcombine/SimplifyCFG should have handled the available opportunities. // If we did this folding here, it would be necessary to update the // MachineBasicBlock CFG, which is awkward. // fold a brcond with a setcc condition into a BR_CC node if BR_CC is legal // on the target. if (N1.getOpcode() == ISD::SETCC && TLI.isOperationLegalOrCustom(ISD::BR_CC, MVT::Other)) { return DAG.getNode(ISD::BR_CC, N->getDebugLoc(), MVT::Other, Chain, N1.getOperand(2), N1.getOperand(0), N1.getOperand(1), N2); } if ((N1.hasOneUse() && N1.getOpcode() == ISD::SRL) || ((N1.getOpcode() == ISD::TRUNCATE && N1.hasOneUse()) && (N1.getOperand(0).hasOneUse() && N1.getOperand(0).getOpcode() == ISD::SRL))) { SDNode *Trunc = 0; if (N1.getOpcode() == ISD::TRUNCATE) { // Look pass the truncate. Trunc = N1.getNode(); N1 = N1.getOperand(0); } // Match this pattern so that we can generate simpler code: // // %a = ... // %b = and i32 %a, 2 // %c = srl i32 %b, 1 // brcond i32 %c ... // // into // // %a = ... // %b = and i32 %a, 2 // %c = setcc eq %b, 0 // brcond %c ... // // This applies only when the AND constant value has one bit set and the // SRL constant is equal to the log2 of the AND constant. The back-end is // smart enough to convert the result into a TEST/JMP sequence. SDValue Op0 = N1.getOperand(0); SDValue Op1 = N1.getOperand(1); if (Op0.getOpcode() == ISD::AND && Op1.getOpcode() == ISD::Constant) { SDValue AndOp1 = Op0.getOperand(1); if (AndOp1.getOpcode() == ISD::Constant) { const APInt &AndConst = cast(AndOp1)->getAPIntValue(); if (AndConst.isPowerOf2() && cast(Op1)->getAPIntValue()==AndConst.logBase2()) { SDValue SetCC = DAG.getSetCC(N->getDebugLoc(), TLI.getSetCCResultType(Op0.getValueType()), Op0, DAG.getConstant(0, Op0.getValueType()), ISD::SETNE); SDValue NewBRCond = DAG.getNode(ISD::BRCOND, N->getDebugLoc(), MVT::Other, Chain, SetCC, N2); // Don't add the new BRCond into the worklist or else SimplifySelectCC // will convert it back to (X & C1) >> C2. CombineTo(N, NewBRCond, false); // Truncate is dead. if (Trunc) { removeFromWorkList(Trunc); DAG.DeleteNode(Trunc); } // Replace the uses of SRL with SETCC WorkListRemover DeadNodes(*this); DAG.ReplaceAllUsesOfValueWith(N1, SetCC, &DeadNodes); removeFromWorkList(N1.getNode()); DAG.DeleteNode(N1.getNode()); return SDValue(N, 0); // Return N so it doesn't get rechecked! } } } if (Trunc) // Restore N1 if the above transformation doesn't match. N1 = N->getOperand(1); } // Transform br(xor(x, y)) -> br(x != y) // Transform br(xor(xor(x,y), 1)) -> br (x == y) if (N1.hasOneUse() && N1.getOpcode() == ISD::XOR) { SDNode *TheXor = N1.getNode(); SDValue Op0 = TheXor->getOperand(0); SDValue Op1 = TheXor->getOperand(1); if (Op0.getOpcode() == Op1.getOpcode()) { // Avoid missing important xor optimizations. SDValue Tmp = visitXOR(TheXor); if (Tmp.getNode() && Tmp.getNode() != TheXor) { DEBUG(dbgs() << "\nReplacing.8 "; TheXor->dump(&DAG); dbgs() << "\nWith: "; Tmp.getNode()->dump(&DAG); dbgs() << '\n'); WorkListRemover DeadNodes(*this); DAG.ReplaceAllUsesOfValueWith(N1, Tmp, &DeadNodes); removeFromWorkList(TheXor); DAG.DeleteNode(TheXor); return DAG.getNode(ISD::BRCOND, N->getDebugLoc(), MVT::Other, Chain, Tmp, N2); } } if (Op0.getOpcode() != ISD::SETCC && Op1.getOpcode() != ISD::SETCC) { bool Equal = false; if (ConstantSDNode *RHSCI = dyn_cast(Op0)) if (RHSCI->getAPIntValue() == 1 && Op0.hasOneUse() && Op0.getOpcode() == ISD::XOR) { TheXor = Op0.getNode(); Equal = true; } EVT SetCCVT = N1.getValueType(); if (LegalTypes) SetCCVT = TLI.getSetCCResultType(SetCCVT); SDValue SetCC = DAG.getSetCC(TheXor->getDebugLoc(), SetCCVT, Op0, Op1, Equal ? ISD::SETEQ : ISD::SETNE); // Replace the uses of XOR with SETCC WorkListRemover DeadNodes(*this); DAG.ReplaceAllUsesOfValueWith(N1, SetCC, &DeadNodes); removeFromWorkList(N1.getNode()); DAG.DeleteNode(N1.getNode()); return DAG.getNode(ISD::BRCOND, N->getDebugLoc(), MVT::Other, Chain, SetCC, N2); } } return SDValue(); } // Operand List for BR_CC: Chain, CondCC, CondLHS, CondRHS, DestBB. // SDValue DAGCombiner::visitBR_CC(SDNode *N) { CondCodeSDNode *CC = cast(N->getOperand(1)); SDValue CondLHS = N->getOperand(2), CondRHS = N->getOperand(3); // If N is a constant we could fold this into a fallthrough or unconditional // branch. However that doesn't happen very often in normal code, because // Instcombine/SimplifyCFG should have handled the available opportunities. // If we did this folding here, it would be necessary to update the // MachineBasicBlock CFG, which is awkward. // Use SimplifySetCC to simplify SETCC's. SDValue Simp = SimplifySetCC(TLI.getSetCCResultType(CondLHS.getValueType()), CondLHS, CondRHS, CC->get(), N->getDebugLoc(), false); if (Simp.getNode()) AddToWorkList(Simp.getNode()); // fold to a simpler setcc if (Simp.getNode() && Simp.getOpcode() == ISD::SETCC) return DAG.getNode(ISD::BR_CC, N->getDebugLoc(), MVT::Other, N->getOperand(0), Simp.getOperand(2), Simp.getOperand(0), Simp.getOperand(1), N->getOperand(4)); return SDValue(); } /// CombineToPreIndexedLoadStore - Try turning a load / store into a /// pre-indexed load / store when the base pointer is an add or subtract /// and it has other uses besides the load / store. After the /// transformation, the new indexed load / store has effectively folded /// the add / subtract in and all of its other uses are redirected to the /// new load / store. bool DAGCombiner::CombineToPreIndexedLoadStore(SDNode *N) { if (!LegalOperations) return false; bool isLoad = true; SDValue Ptr; EVT VT; if (LoadSDNode *LD = dyn_cast(N)) { if (LD->isIndexed()) return false; VT = LD->getMemoryVT(); if (!TLI.isIndexedLoadLegal(ISD::PRE_INC, VT) && !TLI.isIndexedLoadLegal(ISD::PRE_DEC, VT)) return false; Ptr = LD->getBasePtr(); } else if (StoreSDNode *ST = dyn_cast(N)) { if (ST->isIndexed()) return false; VT = ST->getMemoryVT(); if (!TLI.isIndexedStoreLegal(ISD::PRE_INC, VT) && !TLI.isIndexedStoreLegal(ISD::PRE_DEC, VT)) return false; Ptr = ST->getBasePtr(); isLoad = false; } else { return false; } // If the pointer is not an add/sub, or if it doesn't have multiple uses, bail // out. There is no reason to make this a preinc/predec. if ((Ptr.getOpcode() != ISD::ADD && Ptr.getOpcode() != ISD::SUB) || Ptr.getNode()->hasOneUse()) return false; // Ask the target to do addressing mode selection. SDValue BasePtr; SDValue Offset; ISD::MemIndexedMode AM = ISD::UNINDEXED; if (!TLI.getPreIndexedAddressParts(N, BasePtr, Offset, AM, DAG)) return false; // Don't create a indexed load / store with zero offset. if (isa(Offset) && cast(Offset)->isNullValue()) return false; // Try turning it into a pre-indexed load / store except when: // 1) The new base ptr is a frame index. // 2) If N is a store and the new base ptr is either the same as or is a // predecessor of the value being stored. // 3) Another use of old base ptr is a predecessor of N. If ptr is folded // that would create a cycle. // 4) All uses are load / store ops that use it as old base ptr. // Check #1. Preinc'ing a frame index would require copying the stack pointer // (plus the implicit offset) to a register to preinc anyway. if (isa(BasePtr) || isa(BasePtr)) return false; // Check #2. if (!isLoad) { SDValue Val = cast(N)->getValue(); if (Val == BasePtr || BasePtr.getNode()->isPredecessorOf(Val.getNode())) return false; } // Now check for #3 and #4. bool RealUse = false; for (SDNode::use_iterator I = Ptr.getNode()->use_begin(), E = Ptr.getNode()->use_end(); I != E; ++I) { SDNode *Use = *I; if (Use == N) continue; if (Use->isPredecessorOf(N)) return false; if (!((Use->getOpcode() == ISD::LOAD && cast(Use)->getBasePtr() == Ptr) || (Use->getOpcode() == ISD::STORE && cast(Use)->getBasePtr() == Ptr))) RealUse = true; } if (!RealUse) return false; SDValue Result; if (isLoad) Result = DAG.getIndexedLoad(SDValue(N,0), N->getDebugLoc(), BasePtr, Offset, AM); else Result = DAG.getIndexedStore(SDValue(N,0), N->getDebugLoc(), BasePtr, Offset, AM); ++PreIndexedNodes; ++NodesCombined; DEBUG(dbgs() << "\nReplacing.4 "; N->dump(&DAG); dbgs() << "\nWith: "; Result.getNode()->dump(&DAG); dbgs() << '\n'); WorkListRemover DeadNodes(*this); if (isLoad) { DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(0), &DeadNodes); DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Result.getValue(2), &DeadNodes); } else { DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(1), &DeadNodes); } // Finally, since the node is now dead, remove it from the graph. DAG.DeleteNode(N); // Replace the uses of Ptr with uses of the updated base value. DAG.ReplaceAllUsesOfValueWith(Ptr, Result.getValue(isLoad ? 1 : 0), &DeadNodes); removeFromWorkList(Ptr.getNode()); DAG.DeleteNode(Ptr.getNode()); return true; } /// CombineToPostIndexedLoadStore - Try to combine a load / store with a /// add / sub of the base pointer node into a post-indexed load / store. /// The transformation folded the add / subtract into the new indexed /// load / store effectively and all of its uses are redirected to the /// new load / store. bool DAGCombiner::CombineToPostIndexedLoadStore(SDNode *N) { if (!LegalOperations) return false; bool isLoad = true; SDValue Ptr; EVT VT; if (LoadSDNode *LD = dyn_cast(N)) { if (LD->isIndexed()) return false; VT = LD->getMemoryVT(); if (!TLI.isIndexedLoadLegal(ISD::POST_INC, VT) && !TLI.isIndexedLoadLegal(ISD::POST_DEC, VT)) return false; Ptr = LD->getBasePtr(); } else if (StoreSDNode *ST = dyn_cast(N)) { if (ST->isIndexed()) return false; VT = ST->getMemoryVT(); if (!TLI.isIndexedStoreLegal(ISD::POST_INC, VT) && !TLI.isIndexedStoreLegal(ISD::POST_DEC, VT)) return false; Ptr = ST->getBasePtr(); isLoad = false; } else { return false; } if (Ptr.getNode()->hasOneUse()) return false; for (SDNode::use_iterator I = Ptr.getNode()->use_begin(), E = Ptr.getNode()->use_end(); I != E; ++I) { SDNode *Op = *I; if (Op == N || (Op->getOpcode() != ISD::ADD && Op->getOpcode() != ISD::SUB)) continue; SDValue BasePtr; SDValue Offset; ISD::MemIndexedMode AM = ISD::UNINDEXED; if (TLI.getPostIndexedAddressParts(N, Op, BasePtr, Offset, AM, DAG)) { // Don't create a indexed load / store with zero offset. if (isa(Offset) && cast(Offset)->isNullValue()) continue; // Try turning it into a post-indexed load / store except when // 1) All uses are load / store ops that use it as base ptr. // 2) Op must be independent of N, i.e. Op is neither a predecessor // nor a successor of N. Otherwise, if Op is folded that would // create a cycle. if (isa(BasePtr) || isa(BasePtr)) continue; // Check for #1. bool TryNext = false; for (SDNode::use_iterator II = BasePtr.getNode()->use_begin(), EE = BasePtr.getNode()->use_end(); II != EE; ++II) { SDNode *Use = *II; if (Use == Ptr.getNode()) continue; // If all the uses are load / store addresses, then don't do the // transformation. if (Use->getOpcode() == ISD::ADD || Use->getOpcode() == ISD::SUB){ bool RealUse = false; for (SDNode::use_iterator III = Use->use_begin(), EEE = Use->use_end(); III != EEE; ++III) { SDNode *UseUse = *III; if (!((UseUse->getOpcode() == ISD::LOAD && cast(UseUse)->getBasePtr().getNode() == Use) || (UseUse->getOpcode() == ISD::STORE && cast(UseUse)->getBasePtr().getNode() == Use))) RealUse = true; } if (!RealUse) { TryNext = true; break; } } } if (TryNext) continue; // Check for #2 if (!Op->isPredecessorOf(N) && !N->isPredecessorOf(Op)) { SDValue Result = isLoad ? DAG.getIndexedLoad(SDValue(N,0), N->getDebugLoc(), BasePtr, Offset, AM) : DAG.getIndexedStore(SDValue(N,0), N->getDebugLoc(), BasePtr, Offset, AM); ++PostIndexedNodes; ++NodesCombined; DEBUG(dbgs() << "\nReplacing.5 "; N->dump(&DAG); dbgs() << "\nWith: "; Result.getNode()->dump(&DAG); dbgs() << '\n'); WorkListRemover DeadNodes(*this); if (isLoad) { DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(0), &DeadNodes); DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Result.getValue(2), &DeadNodes); } else { DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(1), &DeadNodes); } // Finally, since the node is now dead, remove it from the graph. DAG.DeleteNode(N); // Replace the uses of Use with uses of the updated base value. DAG.ReplaceAllUsesOfValueWith(SDValue(Op, 0), Result.getValue(isLoad ? 1 : 0), &DeadNodes); removeFromWorkList(Op); DAG.DeleteNode(Op); return true; } } } return false; } SDValue DAGCombiner::visitLOAD(SDNode *N) { LoadSDNode *LD = cast(N); SDValue Chain = LD->getChain(); SDValue Ptr = LD->getBasePtr(); // If load is not volatile and there are no uses of the loaded value (and // the updated indexed value in case of indexed loads), change uses of the // chain value into uses of the chain input (i.e. delete the dead load). if (!LD->isVolatile()) { if (N->getValueType(1) == MVT::Other) { // Unindexed loads. if (N->hasNUsesOfValue(0, 0)) { // It's not safe to use the two value CombineTo variant here. e.g. // v1, chain2 = load chain1, loc // v2, chain3 = load chain2, loc // v3 = add v2, c // Now we replace use of chain2 with chain1. This makes the second load // isomorphic to the one we are deleting, and thus makes this load live. DEBUG(dbgs() << "\nReplacing.6 "; N->dump(&DAG); dbgs() << "\nWith chain: "; Chain.getNode()->dump(&DAG); dbgs() << "\n"); WorkListRemover DeadNodes(*this); DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Chain, &DeadNodes); if (N->use_empty()) { removeFromWorkList(N); DAG.DeleteNode(N); } return SDValue(N, 0); // Return N so it doesn't get rechecked! } } else { // Indexed loads. assert(N->getValueType(2) == MVT::Other && "Malformed indexed loads?"); if (N->hasNUsesOfValue(0, 0) && N->hasNUsesOfValue(0, 1)) { SDValue Undef = DAG.getUNDEF(N->getValueType(0)); DEBUG(dbgs() << "\nReplacing.7 "; N->dump(&DAG); dbgs() << "\nWith: "; Undef.getNode()->dump(&DAG); dbgs() << " and 2 other values\n"); WorkListRemover DeadNodes(*this); DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Undef, &DeadNodes); DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), DAG.getUNDEF(N->getValueType(1)), &DeadNodes); DAG.ReplaceAllUsesOfValueWith(SDValue(N, 2), Chain, &DeadNodes); removeFromWorkList(N); DAG.DeleteNode(N); return SDValue(N, 0); // Return N so it doesn't get rechecked! } } } // If this load is directly stored, replace the load value with the stored // value. // TODO: Handle store large -> read small portion. // TODO: Handle TRUNCSTORE/LOADEXT if (ISD::isNormalLoad(N) && !LD->isVolatile()) { if (ISD::isNON_TRUNCStore(Chain.getNode())) { StoreSDNode *PrevST = cast(Chain); if (PrevST->getBasePtr() == Ptr && PrevST->getValue().getValueType() == N->getValueType(0)) return CombineTo(N, Chain.getOperand(1), Chain); } } // Try to infer better alignment information than the load already has. if (OptLevel != CodeGenOpt::None && LD->isUnindexed()) { if (unsigned Align = DAG.InferPtrAlignment(Ptr)) { if (Align > LD->getAlignment()) return DAG.getExtLoad(LD->getExtensionType(), N->getDebugLoc(), LD->getValueType(0), Chain, Ptr, LD->getPointerInfo(), LD->getMemoryVT(), LD->isVolatile(), LD->isNonTemporal(), Align); } } if (CombinerAA) { // Walk up chain skipping non-aliasing memory nodes. SDValue BetterChain = FindBetterChain(N, Chain); // If there is a better chain. if (Chain != BetterChain) { SDValue ReplLoad; // Replace the chain to void dependency. if (LD->getExtensionType() == ISD::NON_EXTLOAD) { ReplLoad = DAG.getLoad(N->getValueType(0), LD->getDebugLoc(), BetterChain, Ptr, LD->getPointerInfo(), LD->isVolatile(), LD->isNonTemporal(), LD->getAlignment()); } else { ReplLoad = DAG.getExtLoad(LD->getExtensionType(), LD->getDebugLoc(), LD->getValueType(0), BetterChain, Ptr, LD->getPointerInfo(), LD->getMemoryVT(), LD->isVolatile(), LD->isNonTemporal(), LD->getAlignment()); } // Create token factor to keep old chain connected. SDValue Token = DAG.getNode(ISD::TokenFactor, N->getDebugLoc(), MVT::Other, Chain, ReplLoad.getValue(1)); // Make sure the new and old chains are cleaned up. AddToWorkList(Token.getNode()); // Replace uses with load result and token factor. Don't add users // to work list. return CombineTo(N, ReplLoad.getValue(0), Token, false); } } // Try transforming N to an indexed load. if (CombineToPreIndexedLoadStore(N) || CombineToPostIndexedLoadStore(N)) return SDValue(N, 0); return SDValue(); } /// CheckForMaskedLoad - Check to see if V is (and load (ptr), imm), where the /// load is having specific bytes cleared out. If so, return the byte size /// being masked out and the shift amount. static std::pair CheckForMaskedLoad(SDValue V, SDValue Ptr, SDValue Chain) { std::pair Result(0, 0); // Check for the structure we're looking for. if (V->getOpcode() != ISD::AND || !isa(V->getOperand(1)) || !ISD::isNormalLoad(V->getOperand(0).getNode())) return Result; // Check the chain and pointer. LoadSDNode *LD = cast(V->getOperand(0)); if (LD->getBasePtr() != Ptr) return Result; // Not from same pointer. // The store should be chained directly to the load or be an operand of a // tokenfactor. if (LD == Chain.getNode()) ; // ok. else if (Chain->getOpcode() != ISD::TokenFactor) return Result; // Fail. else { bool isOk = false; for (unsigned i = 0, e = Chain->getNumOperands(); i != e; ++i) if (Chain->getOperand(i).getNode() == LD) { isOk = true; break; } if (!isOk) return Result; } // This only handles simple types. if (V.getValueType() != MVT::i16 && V.getValueType() != MVT::i32 && V.getValueType() != MVT::i64) return Result; // Check the constant mask. Invert it so that the bits being masked out are // 0 and the bits being kept are 1. Use getSExtValue so that leading bits // follow the sign bit for uniformity. uint64_t NotMask = ~cast(V->getOperand(1))->getSExtValue(); unsigned NotMaskLZ = CountLeadingZeros_64(NotMask); if (NotMaskLZ & 7) return Result; // Must be multiple of a byte. unsigned NotMaskTZ = CountTrailingZeros_64(NotMask); if (NotMaskTZ & 7) return Result; // Must be multiple of a byte. if (NotMaskLZ == 64) return Result; // All zero mask. // See if we have a continuous run of bits. If so, we have 0*1+0* if (CountTrailingOnes_64(NotMask >> NotMaskTZ)+NotMaskTZ+NotMaskLZ != 64) return Result; // Adjust NotMaskLZ down to be from the actual size of the int instead of i64. if (V.getValueType() != MVT::i64 && NotMaskLZ) NotMaskLZ -= 64-V.getValueSizeInBits(); unsigned MaskedBytes = (V.getValueSizeInBits()-NotMaskLZ-NotMaskTZ)/8; switch (MaskedBytes) { case 1: case 2: case 4: break; default: return Result; // All one mask, or 5-byte mask. } // Verify that the first bit starts at a multiple of mask so that the access // is aligned the same as the access width. if (NotMaskTZ && NotMaskTZ/8 % MaskedBytes) return Result; Result.first = MaskedBytes; Result.second = NotMaskTZ/8; return Result; } /// ShrinkLoadReplaceStoreWithStore - Check to see if IVal is something that /// provides a value as specified by MaskInfo. If so, replace the specified /// store with a narrower store of truncated IVal. static SDNode * ShrinkLoadReplaceStoreWithStore(const std::pair &MaskInfo, SDValue IVal, StoreSDNode *St, DAGCombiner *DC) { unsigned NumBytes = MaskInfo.first; unsigned ByteShift = MaskInfo.second; SelectionDAG &DAG = DC->getDAG(); // Check to see if IVal is all zeros in the part being masked in by the 'or' // that uses this. If not, this is not a replacement. APInt Mask = ~APInt::getBitsSet(IVal.getValueSizeInBits(), ByteShift*8, (ByteShift+NumBytes)*8); if (!DAG.MaskedValueIsZero(IVal, Mask)) return 0; // Check that it is legal on the target to do this. It is legal if the new // VT we're shrinking to (i8/i16/i32) is legal or we're still before type // legalization. MVT VT = MVT::getIntegerVT(NumBytes*8); if (!DC->isTypeLegal(VT)) return 0; // Okay, we can do this! Replace the 'St' store with a store of IVal that is // shifted by ByteShift and truncated down to NumBytes. if (ByteShift) IVal = DAG.getNode(ISD::SRL, IVal->getDebugLoc(), IVal.getValueType(), IVal, DAG.getConstant(ByteShift*8, DC->getShiftAmountTy(IVal.getValueType()))); // Figure out the offset for the store and the alignment of the access. unsigned StOffset; unsigned NewAlign = St->getAlignment(); if (DAG.getTargetLoweringInfo().isLittleEndian()) StOffset = ByteShift; else StOffset = IVal.getValueType().getStoreSize() - ByteShift - NumBytes; SDValue Ptr = St->getBasePtr(); if (StOffset) { Ptr = DAG.getNode(ISD::ADD, IVal->getDebugLoc(), Ptr.getValueType(), Ptr, DAG.getConstant(StOffset, Ptr.getValueType())); NewAlign = MinAlign(NewAlign, StOffset); } // Truncate down to the new size. IVal = DAG.getNode(ISD::TRUNCATE, IVal->getDebugLoc(), VT, IVal); ++OpsNarrowed; return DAG.getStore(St->getChain(), St->getDebugLoc(), IVal, Ptr, St->getPointerInfo().getWithOffset(StOffset), false, false, NewAlign).getNode(); } /// ReduceLoadOpStoreWidth - Look for sequence of load / op / store where op is /// one of 'or', 'xor', and 'and' of immediates. If 'op' is only touching some /// of the loaded bits, try narrowing the load and store if it would end up /// being a win for performance or code size. SDValue DAGCombiner::ReduceLoadOpStoreWidth(SDNode *N) { StoreSDNode *ST = cast(N); if (ST->isVolatile()) return SDValue(); SDValue Chain = ST->getChain(); SDValue Value = ST->getValue(); SDValue Ptr = ST->getBasePtr(); EVT VT = Value.getValueType(); if (ST->isTruncatingStore() || VT.isVector() || !Value.hasOneUse()) return SDValue(); unsigned Opc = Value.getOpcode(); // If this is "store (or X, Y), P" and X is "(and (load P), cst)", where cst // is a byte mask indicating a consecutive number of bytes, check to see if // Y is known to provide just those bytes. If so, we try to replace the // load + replace + store sequence with a single (narrower) store, which makes // the load dead. if (Opc == ISD::OR) { std::pair MaskedLoad; MaskedLoad = CheckForMaskedLoad(Value.getOperand(0), Ptr, Chain); if (MaskedLoad.first) if (SDNode *NewST = ShrinkLoadReplaceStoreWithStore(MaskedLoad, Value.getOperand(1), ST,this)) return SDValue(NewST, 0); // Or is commutative, so try swapping X and Y. MaskedLoad = CheckForMaskedLoad(Value.getOperand(1), Ptr, Chain); if (MaskedLoad.first) if (SDNode *NewST = ShrinkLoadReplaceStoreWithStore(MaskedLoad, Value.getOperand(0), ST,this)) return SDValue(NewST, 0); } if ((Opc != ISD::OR && Opc != ISD::XOR && Opc != ISD::AND) || Value.getOperand(1).getOpcode() != ISD::Constant) return SDValue(); SDValue N0 = Value.getOperand(0); if (ISD::isNormalLoad(N0.getNode()) && N0.hasOneUse() && Chain == SDValue(N0.getNode(), 1)) { LoadSDNode *LD = cast(N0); if (LD->getBasePtr() != Ptr || LD->getPointerInfo().getAddrSpace() != ST->getPointerInfo().getAddrSpace()) return SDValue(); // Find the type to narrow it the load / op / store to. SDValue N1 = Value.getOperand(1); unsigned BitWidth = N1.getValueSizeInBits(); APInt Imm = cast(N1)->getAPIntValue(); if (Opc == ISD::AND) Imm ^= APInt::getAllOnesValue(BitWidth); if (Imm == 0 || Imm.isAllOnesValue()) return SDValue(); unsigned ShAmt = Imm.countTrailingZeros(); unsigned MSB = BitWidth - Imm.countLeadingZeros() - 1; unsigned NewBW = NextPowerOf2(MSB - ShAmt); EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), NewBW); while (NewBW < BitWidth && !(TLI.isOperationLegalOrCustom(Opc, NewVT) && TLI.isNarrowingProfitable(VT, NewVT))) { NewBW = NextPowerOf2(NewBW); NewVT = EVT::getIntegerVT(*DAG.getContext(), NewBW); } if (NewBW >= BitWidth) return SDValue(); // If the lsb changed does not start at the type bitwidth boundary, // start at the previous one. if (ShAmt % NewBW) ShAmt = (((ShAmt + NewBW - 1) / NewBW) * NewBW) - NewBW; APInt Mask = APInt::getBitsSet(BitWidth, ShAmt, ShAmt + NewBW); if ((Imm & Mask) == Imm) { APInt NewImm = (Imm & Mask).lshr(ShAmt).trunc(NewBW); if (Opc == ISD::AND) NewImm ^= APInt::getAllOnesValue(NewBW); uint64_t PtrOff = ShAmt / 8; // For big endian targets, we need to adjust the offset to the pointer to // load the correct bytes. if (TLI.isBigEndian()) PtrOff = (BitWidth + 7 - NewBW) / 8 - PtrOff; unsigned NewAlign = MinAlign(LD->getAlignment(), PtrOff); const Type *NewVTTy = NewVT.getTypeForEVT(*DAG.getContext()); if (NewAlign < TLI.getTargetData()->getABITypeAlignment(NewVTTy)) return SDValue(); SDValue NewPtr = DAG.getNode(ISD::ADD, LD->getDebugLoc(), Ptr.getValueType(), Ptr, DAG.getConstant(PtrOff, Ptr.getValueType())); SDValue NewLD = DAG.getLoad(NewVT, N0.getDebugLoc(), LD->getChain(), NewPtr, LD->getPointerInfo().getWithOffset(PtrOff), LD->isVolatile(), LD->isNonTemporal(), NewAlign); SDValue NewVal = DAG.getNode(Opc, Value.getDebugLoc(), NewVT, NewLD, DAG.getConstant(NewImm, NewVT)); SDValue NewST = DAG.getStore(Chain, N->getDebugLoc(), NewVal, NewPtr, ST->getPointerInfo().getWithOffset(PtrOff), false, false, NewAlign); AddToWorkList(NewPtr.getNode()); AddToWorkList(NewLD.getNode()); AddToWorkList(NewVal.getNode()); WorkListRemover DeadNodes(*this); DAG.ReplaceAllUsesOfValueWith(N0.getValue(1), NewLD.getValue(1), &DeadNodes); ++OpsNarrowed; return NewST; } } return SDValue(); } /// TransformFPLoadStorePair - For a given floating point load / store pair, /// if the load value isn't used by any other operations, then consider /// transforming the pair to integer load / store operations if the target /// deems the transformation profitable. SDValue DAGCombiner::TransformFPLoadStorePair(SDNode *N) { StoreSDNode *ST = cast(N); SDValue Chain = ST->getChain(); SDValue Value = ST->getValue(); if (ISD::isNormalStore(ST) && ISD::isNormalLoad(Value.getNode()) && Value.hasOneUse() && Chain == SDValue(Value.getNode(), 1)) { LoadSDNode *LD = cast(Value); EVT VT = LD->getMemoryVT(); if (!VT.isFloatingPoint() || VT != ST->getMemoryVT() || LD->isNonTemporal() || ST->isNonTemporal() || LD->getPointerInfo().getAddrSpace() != 0 || ST->getPointerInfo().getAddrSpace() != 0) return SDValue(); EVT IntVT = EVT::getIntegerVT(*DAG.getContext(), VT.getSizeInBits()); if (!TLI.isOperationLegal(ISD::LOAD, IntVT) || !TLI.isOperationLegal(ISD::STORE, IntVT) || !TLI.isDesirableToTransformToIntegerOp(ISD::LOAD, VT) || !TLI.isDesirableToTransformToIntegerOp(ISD::STORE, VT)) return SDValue(); unsigned LDAlign = LD->getAlignment(); unsigned STAlign = ST->getAlignment(); const Type *IntVTTy = IntVT.getTypeForEVT(*DAG.getContext()); unsigned ABIAlign = TLI.getTargetData()->getABITypeAlignment(IntVTTy); if (LDAlign < ABIAlign || STAlign < ABIAlign) return SDValue(); SDValue NewLD = DAG.getLoad(IntVT, Value.getDebugLoc(), LD->getChain(), LD->getBasePtr(), LD->getPointerInfo(), false, false, LDAlign); SDValue NewST = DAG.getStore(NewLD.getValue(1), N->getDebugLoc(), NewLD, ST->getBasePtr(), ST->getPointerInfo(), false, false, STAlign); AddToWorkList(NewLD.getNode()); AddToWorkList(NewST.getNode()); WorkListRemover DeadNodes(*this); DAG.ReplaceAllUsesOfValueWith(Value.getValue(1), NewLD.getValue(1), &DeadNodes); ++LdStFP2Int; return NewST; } return SDValue(); } SDValue DAGCombiner::visitSTORE(SDNode *N) { StoreSDNode *ST = cast(N); SDValue Chain = ST->getChain(); SDValue Value = ST->getValue(); SDValue Ptr = ST->getBasePtr(); // If this is a store of a bit convert, store the input value if the // resultant store does not need a higher alignment than the original. if (Value.getOpcode() == ISD::BITCAST && !ST->isTruncatingStore() && ST->isUnindexed()) { unsigned OrigAlign = ST->getAlignment(); EVT SVT = Value.getOperand(0).getValueType(); unsigned Align = TLI.getTargetData()-> getABITypeAlignment(SVT.getTypeForEVT(*DAG.getContext())); if (Align <= OrigAlign && ((!LegalOperations && !ST->isVolatile()) || TLI.isOperationLegalOrCustom(ISD::STORE, SVT))) return DAG.getStore(Chain, N->getDebugLoc(), Value.getOperand(0), Ptr, ST->getPointerInfo(), ST->isVolatile(), ST->isNonTemporal(), OrigAlign); } // Turn 'store float 1.0, Ptr' -> 'store int 0x12345678, Ptr' if (ConstantFPSDNode *CFP = dyn_cast(Value)) { // NOTE: If the original store is volatile, this transform must not increase // the number of stores. For example, on x86-32 an f64 can be stored in one // processor operation but an i64 (which is not legal) requires two. So the // transform should not be done in this case. if (Value.getOpcode() != ISD::TargetConstantFP) { SDValue Tmp; switch (CFP->getValueType(0).getSimpleVT().SimpleTy) { default: llvm_unreachable("Unknown FP type"); case MVT::f80: // We don't do this for these yet. case MVT::f128: case MVT::ppcf128: break; case MVT::f32: if ((isTypeLegal(MVT::i32) && !LegalOperations && !ST->isVolatile()) || TLI.isOperationLegalOrCustom(ISD::STORE, MVT::i32)) { Tmp = DAG.getConstant((uint32_t)CFP->getValueAPF(). bitcastToAPInt().getZExtValue(), MVT::i32); return DAG.getStore(Chain, N->getDebugLoc(), Tmp, Ptr, ST->getPointerInfo(), ST->isVolatile(), ST->isNonTemporal(), ST->getAlignment()); } break; case MVT::f64: if ((TLI.isTypeLegal(MVT::i64) && !LegalOperations && !ST->isVolatile()) || TLI.isOperationLegalOrCustom(ISD::STORE, MVT::i64)) { Tmp = DAG.getConstant(CFP->getValueAPF().bitcastToAPInt(). getZExtValue(), MVT::i64); return DAG.getStore(Chain, N->getDebugLoc(), Tmp, Ptr, ST->getPointerInfo(), ST->isVolatile(), ST->isNonTemporal(), ST->getAlignment()); } else if (!ST->isVolatile() && TLI.isOperationLegalOrCustom(ISD::STORE, MVT::i32)) { // Many FP stores are not made apparent until after legalize, e.g. for // argument passing. Since this is so common, custom legalize the // 64-bit integer store into two 32-bit stores. uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue(); SDValue Lo = DAG.getConstant(Val & 0xFFFFFFFF, MVT::i32); SDValue Hi = DAG.getConstant(Val >> 32, MVT::i32); if (TLI.isBigEndian()) std::swap(Lo, Hi); unsigned Alignment = ST->getAlignment(); bool isVolatile = ST->isVolatile(); bool isNonTemporal = ST->isNonTemporal(); SDValue St0 = DAG.getStore(Chain, ST->getDebugLoc(), Lo, Ptr, ST->getPointerInfo(), isVolatile, isNonTemporal, ST->getAlignment()); Ptr = DAG.getNode(ISD::ADD, N->getDebugLoc(), Ptr.getValueType(), Ptr, DAG.getConstant(4, Ptr.getValueType())); Alignment = MinAlign(Alignment, 4U); SDValue St1 = DAG.getStore(Chain, ST->getDebugLoc(), Hi, Ptr, ST->getPointerInfo().getWithOffset(4), isVolatile, isNonTemporal, Alignment); return DAG.getNode(ISD::TokenFactor, N->getDebugLoc(), MVT::Other, St0, St1); } break; } } } // Try to infer better alignment information than the store already has. if (OptLevel != CodeGenOpt::None && ST->isUnindexed()) { if (unsigned Align = DAG.InferPtrAlignment(Ptr)) { if (Align > ST->getAlignment()) return DAG.getTruncStore(Chain, N->getDebugLoc(), Value, Ptr, ST->getPointerInfo(), ST->getMemoryVT(), ST->isVolatile(), ST->isNonTemporal(), Align); } } // Try transforming a pair floating point load / store ops to integer // load / store ops. SDValue NewST = TransformFPLoadStorePair(N); if (NewST.getNode()) return NewST; if (CombinerAA) { // Walk up chain skipping non-aliasing memory nodes. SDValue BetterChain = FindBetterChain(N, Chain); // If there is a better chain. if (Chain != BetterChain) { SDValue ReplStore; // Replace the chain to avoid dependency. if (ST->isTruncatingStore()) { ReplStore = DAG.getTruncStore(BetterChain, N->getDebugLoc(), Value, Ptr, ST->getPointerInfo(), ST->getMemoryVT(), ST->isVolatile(), ST->isNonTemporal(), ST->getAlignment()); } else { ReplStore = DAG.getStore(BetterChain, N->getDebugLoc(), Value, Ptr, ST->getPointerInfo(), ST->isVolatile(), ST->isNonTemporal(), ST->getAlignment()); } // Create token to keep both nodes around. SDValue Token = DAG.getNode(ISD::TokenFactor, N->getDebugLoc(), MVT::Other, Chain, ReplStore); // Make sure the new and old chains are cleaned up. AddToWorkList(Token.getNode()); // Don't add users to work list. return CombineTo(N, Token, false); } } // Try transforming N to an indexed store. if (CombineToPreIndexedLoadStore(N) || CombineToPostIndexedLoadStore(N)) return SDValue(N, 0); // FIXME: is there such a thing as a truncating indexed store? if (ST->isTruncatingStore() && ST->isUnindexed() && Value.getValueType().isInteger()) { // See if we can simplify the input to this truncstore with knowledge that // only the low bits are being used. For example: // "truncstore (or (shl x, 8), y), i8" -> "truncstore y, i8" SDValue Shorter = GetDemandedBits(Value, APInt::getLowBitsSet(Value.getValueSizeInBits(), ST->getMemoryVT().getSizeInBits())); AddToWorkList(Value.getNode()); if (Shorter.getNode()) return DAG.getTruncStore(Chain, N->getDebugLoc(), Shorter, Ptr, ST->getPointerInfo(), ST->getMemoryVT(), ST->isVolatile(), ST->isNonTemporal(), ST->getAlignment()); // Otherwise, see if we can simplify the operation with // SimplifyDemandedBits, which only works if the value has a single use. if (SimplifyDemandedBits(Value, APInt::getLowBitsSet( Value.getValueType().getScalarType().getSizeInBits(), ST->getMemoryVT().getScalarType().getSizeInBits()))) return SDValue(N, 0); } // If this is a load followed by a store to the same location, then the store // is dead/noop. if (LoadSDNode *Ld = dyn_cast(Value)) { if (Ld->getBasePtr() == Ptr && ST->getMemoryVT() == Ld->getMemoryVT() && ST->isUnindexed() && !ST->isVolatile() && // There can't be any side effects between the load and store, such as // a call or store. Chain.reachesChainWithoutSideEffects(SDValue(Ld, 1))) { // The store is dead, remove it. return Chain; } } // If this is an FP_ROUND or TRUNC followed by a store, fold this into a // truncating store. We can do this even if this is already a truncstore. if ((Value.getOpcode() == ISD::FP_ROUND || Value.getOpcode() == ISD::TRUNCATE) && Value.getNode()->hasOneUse() && ST->isUnindexed() && TLI.isTruncStoreLegal(Value.getOperand(0).getValueType(), ST->getMemoryVT())) { return DAG.getTruncStore(Chain, N->getDebugLoc(), Value.getOperand(0), Ptr, ST->getPointerInfo(), ST->getMemoryVT(), ST->isVolatile(), ST->isNonTemporal(), ST->getAlignment()); } return ReduceLoadOpStoreWidth(N); } SDValue DAGCombiner::visitINSERT_VECTOR_ELT(SDNode *N) { SDValue InVec = N->getOperand(0); SDValue InVal = N->getOperand(1); SDValue EltNo = N->getOperand(2); // If the inserted element is an UNDEF, just use the input vector. if (InVal.getOpcode() == ISD::UNDEF) return InVec; EVT VT = InVec.getValueType(); // If we can't generate a legal BUILD_VECTOR, exit if (LegalOperations && !TLI.isOperationLegal(ISD::BUILD_VECTOR, VT)) return SDValue(); // If the invec is a BUILD_VECTOR and if EltNo is a constant, build a new // vector with the inserted element. if (InVec.getOpcode() == ISD::BUILD_VECTOR && isa(EltNo)) { unsigned Elt = cast(EltNo)->getZExtValue(); SmallVector Ops(InVec.getNode()->op_begin(), InVec.getNode()->op_end()); if (Elt < Ops.size()) Ops[Elt] = InVal; return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), VT, &Ops[0], Ops.size()); } // If the invec is an UNDEF and if EltNo is a constant, create a new // BUILD_VECTOR with undef elements and the inserted element. if (InVec.getOpcode() == ISD::UNDEF && isa(EltNo)) { EVT EltVT = VT.getVectorElementType(); unsigned NElts = VT.getVectorNumElements(); SmallVector Ops(NElts, DAG.getUNDEF(EltVT)); unsigned Elt = cast(EltNo)->getZExtValue(); if (Elt < Ops.size()) Ops[Elt] = InVal; return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), VT, &Ops[0], Ops.size()); } return SDValue(); } SDValue DAGCombiner::visitEXTRACT_VECTOR_ELT(SDNode *N) { // (vextract (scalar_to_vector val, 0) -> val SDValue InVec = N->getOperand(0); if (InVec.getOpcode() == ISD::SCALAR_TO_VECTOR) { // Check if the result type doesn't match the inserted element type. A // SCALAR_TO_VECTOR may truncate the inserted element and the // EXTRACT_VECTOR_ELT may widen the extracted vector. SDValue InOp = InVec.getOperand(0); EVT NVT = N->getValueType(0); if (InOp.getValueType() != NVT) { assert(InOp.getValueType().isInteger() && NVT.isInteger()); return DAG.getSExtOrTrunc(InOp, InVec.getDebugLoc(), NVT); } return InOp; } // Perform only after legalization to ensure build_vector / vector_shuffle // optimizations have already been done. if (!LegalOperations) return SDValue(); // (vextract (v4f32 load $addr), c) -> (f32 load $addr+c*size) // (vextract (v4f32 s2v (f32 load $addr)), c) -> (f32 load $addr+c*size) // (vextract (v4f32 shuffle (load $addr), <1,u,u,u>), 0) -> (f32 load $addr) SDValue EltNo = N->getOperand(1); if (isa(EltNo)) { int Elt = cast(EltNo)->getZExtValue(); bool NewLoad = false; bool BCNumEltsChanged = false; EVT VT = InVec.getValueType(); EVT ExtVT = VT.getVectorElementType(); EVT LVT = ExtVT; if (InVec.getOpcode() == ISD::BITCAST) { EVT BCVT = InVec.getOperand(0).getValueType(); if (!BCVT.isVector() || ExtVT.bitsGT(BCVT.getVectorElementType())) return SDValue(); if (VT.getVectorNumElements() != BCVT.getVectorNumElements()) BCNumEltsChanged = true; InVec = InVec.getOperand(0); ExtVT = BCVT.getVectorElementType(); NewLoad = true; } LoadSDNode *LN0 = NULL; const ShuffleVectorSDNode *SVN = NULL; if (ISD::isNormalLoad(InVec.getNode())) { LN0 = cast(InVec); } else if (InVec.getOpcode() == ISD::SCALAR_TO_VECTOR && InVec.getOperand(0).getValueType() == ExtVT && ISD::isNormalLoad(InVec.getOperand(0).getNode())) { LN0 = cast(InVec.getOperand(0)); } else if ((SVN = dyn_cast(InVec))) { // (vextract (vector_shuffle (load $addr), v2, <1, u, u, u>), 1) // => // (load $addr+1*size) // If the bit convert changed the number of elements, it is unsafe // to examine the mask. if (BCNumEltsChanged) return SDValue(); // Select the input vector, guarding against out of range extract vector. unsigned NumElems = VT.getVectorNumElements(); int Idx = (Elt > (int)NumElems) ? -1 : SVN->getMaskElt(Elt); InVec = (Idx < (int)NumElems) ? InVec.getOperand(0) : InVec.getOperand(1); if (InVec.getOpcode() == ISD::BITCAST) InVec = InVec.getOperand(0); if (ISD::isNormalLoad(InVec.getNode())) { LN0 = cast(InVec); Elt = (Idx < (int)NumElems) ? Idx : Idx - (int)NumElems; } } if (!LN0 || !LN0->hasOneUse() || LN0->isVolatile()) return SDValue(); // If Idx was -1 above, Elt is going to be -1, so just return undef. if (Elt == -1) return DAG.getUNDEF(LN0->getBasePtr().getValueType()); unsigned Align = LN0->getAlignment(); if (NewLoad) { // Check the resultant load doesn't need a higher alignment than the // original load. unsigned NewAlign = TLI.getTargetData() ->getABITypeAlignment(LVT.getTypeForEVT(*DAG.getContext())); if (NewAlign > Align || !TLI.isOperationLegalOrCustom(ISD::LOAD, LVT)) return SDValue(); Align = NewAlign; } SDValue NewPtr = LN0->getBasePtr(); unsigned PtrOff = 0; if (Elt) { PtrOff = LVT.getSizeInBits() * Elt / 8; EVT PtrType = NewPtr.getValueType(); if (TLI.isBigEndian()) PtrOff = VT.getSizeInBits() / 8 - PtrOff; NewPtr = DAG.getNode(ISD::ADD, N->getDebugLoc(), PtrType, NewPtr, DAG.getConstant(PtrOff, PtrType)); } return DAG.getLoad(LVT, N->getDebugLoc(), LN0->getChain(), NewPtr, LN0->getPointerInfo().getWithOffset(PtrOff), LN0->isVolatile(), LN0->isNonTemporal(), Align); } return SDValue(); } SDValue DAGCombiner::visitBUILD_VECTOR(SDNode *N) { unsigned NumInScalars = N->getNumOperands(); EVT VT = N->getValueType(0); // Check to see if this is a BUILD_VECTOR of a bunch of EXTRACT_VECTOR_ELT // operations. If so, and if the EXTRACT_VECTOR_ELT vector inputs come from // at most two distinct vectors, turn this into a shuffle node. SDValue VecIn1, VecIn2; for (unsigned i = 0; i != NumInScalars; ++i) { // Ignore undef inputs. if (N->getOperand(i).getOpcode() == ISD::UNDEF) continue; // If this input is something other than a EXTRACT_VECTOR_ELT with a // constant index, bail out. if (N->getOperand(i).getOpcode() != ISD::EXTRACT_VECTOR_ELT || !isa(N->getOperand(i).getOperand(1))) { VecIn1 = VecIn2 = SDValue(0, 0); break; } // If the input vector type disagrees with the result of the build_vector, // we can't make a shuffle. SDValue ExtractedFromVec = N->getOperand(i).getOperand(0); if (ExtractedFromVec.getValueType() != VT) { VecIn1 = VecIn2 = SDValue(0, 0); break; } // Otherwise, remember this. We allow up to two distinct input vectors. if (ExtractedFromVec == VecIn1 || ExtractedFromVec == VecIn2) continue; if (VecIn1.getNode() == 0) { VecIn1 = ExtractedFromVec; } else if (VecIn2.getNode() == 0) { VecIn2 = ExtractedFromVec; } else { // Too many inputs. VecIn1 = VecIn2 = SDValue(0, 0); break; } } // If everything is good, we can make a shuffle operation. if (VecIn1.getNode()) { SmallVector Mask; for (unsigned i = 0; i != NumInScalars; ++i) { if (N->getOperand(i).getOpcode() == ISD::UNDEF) { Mask.push_back(-1); continue; } // If extracting from the first vector, just use the index directly. SDValue Extract = N->getOperand(i); SDValue ExtVal = Extract.getOperand(1); if (Extract.getOperand(0) == VecIn1) { unsigned ExtIndex = cast(ExtVal)->getZExtValue(); if (ExtIndex > VT.getVectorNumElements()) return SDValue(); Mask.push_back(ExtIndex); continue; } // Otherwise, use InIdx + VecSize unsigned Idx = cast(ExtVal)->getZExtValue(); Mask.push_back(Idx+NumInScalars); } // Add count and size info. if (!isTypeLegal(VT)) return SDValue(); // Return the new VECTOR_SHUFFLE node. SDValue Ops[2]; Ops[0] = VecIn1; Ops[1] = VecIn2.getNode() ? VecIn2 : DAG.getUNDEF(VT); return DAG.getVectorShuffle(VT, N->getDebugLoc(), Ops[0], Ops[1], &Mask[0]); } return SDValue(); } SDValue DAGCombiner::visitCONCAT_VECTORS(SDNode *N) { // TODO: Check to see if this is a CONCAT_VECTORS of a bunch of // EXTRACT_SUBVECTOR operations. If so, and if the EXTRACT_SUBVECTOR vector // inputs come from at most two distinct vectors, turn this into a shuffle // node. // If we only have one input vector, we don't need to do any concatenation. if (N->getNumOperands() == 1) return N->getOperand(0); return SDValue(); } SDValue DAGCombiner::visitVECTOR_SHUFFLE(SDNode *N) { EVT VT = N->getValueType(0); unsigned NumElts = VT.getVectorNumElements(); SDValue N0 = N->getOperand(0); assert(N0.getValueType().getVectorNumElements() == NumElts && "Vector shuffle must be normalized in DAG"); // FIXME: implement canonicalizations from DAG.getVectorShuffle() // If it is a splat, check if the argument vector is another splat or a // build_vector with all scalar elements the same. ShuffleVectorSDNode *SVN = cast(N); if (SVN->isSplat() && SVN->getSplatIndex() < (int)NumElts) { SDNode *V = N0.getNode(); // If this is a bit convert that changes the element type of the vector but // not the number of vector elements, look through it. Be careful not to // look though conversions that change things like v4f32 to v2f64. if (V->getOpcode() == ISD::BITCAST) { SDValue ConvInput = V->getOperand(0); if (ConvInput.getValueType().isVector() && ConvInput.getValueType().getVectorNumElements() == NumElts) V = ConvInput.getNode(); } if (V->getOpcode() == ISD::BUILD_VECTOR) { assert(V->getNumOperands() == NumElts && "BUILD_VECTOR has wrong number of operands"); SDValue Base; bool AllSame = true; for (unsigned i = 0; i != NumElts; ++i) { if (V->getOperand(i).getOpcode() != ISD::UNDEF) { Base = V->getOperand(i); break; } } // Splat of , return if (!Base.getNode()) return N0; for (unsigned i = 0; i != NumElts; ++i) { if (V->getOperand(i) != Base) { AllSame = false; break; } } // Splat of , return if (AllSame) return N0; } } return SDValue(); } SDValue DAGCombiner::visitMEMBARRIER(SDNode* N) { if (!TLI.getShouldFoldAtomicFences()) return SDValue(); SDValue atomic = N->getOperand(0); switch (atomic.getOpcode()) { case ISD::ATOMIC_CMP_SWAP: case ISD::ATOMIC_SWAP: case ISD::ATOMIC_LOAD_ADD: case ISD::ATOMIC_LOAD_SUB: case ISD::ATOMIC_LOAD_AND: case ISD::ATOMIC_LOAD_OR: case ISD::ATOMIC_LOAD_XOR: case ISD::ATOMIC_LOAD_NAND: case ISD::ATOMIC_LOAD_MIN: case ISD::ATOMIC_LOAD_MAX: case ISD::ATOMIC_LOAD_UMIN: case ISD::ATOMIC_LOAD_UMAX: break; default: return SDValue(); } SDValue fence = atomic.getOperand(0); if (fence.getOpcode() != ISD::MEMBARRIER) return SDValue(); switch (atomic.getOpcode()) { case ISD::ATOMIC_CMP_SWAP: return SDValue(DAG.UpdateNodeOperands(atomic.getNode(), fence.getOperand(0), atomic.getOperand(1), atomic.getOperand(2), atomic.getOperand(3)), atomic.getResNo()); case ISD::ATOMIC_SWAP: case ISD::ATOMIC_LOAD_ADD: case ISD::ATOMIC_LOAD_SUB: case ISD::ATOMIC_LOAD_AND: case ISD::ATOMIC_LOAD_OR: case ISD::ATOMIC_LOAD_XOR: case ISD::ATOMIC_LOAD_NAND: case ISD::ATOMIC_LOAD_MIN: case ISD::ATOMIC_LOAD_MAX: case ISD::ATOMIC_LOAD_UMIN: case ISD::ATOMIC_LOAD_UMAX: return SDValue(DAG.UpdateNodeOperands(atomic.getNode(), fence.getOperand(0), atomic.getOperand(1), atomic.getOperand(2)), atomic.getResNo()); default: return SDValue(); } } /// XformToShuffleWithZero - Returns a vector_shuffle if it able to transform /// an AND to a vector_shuffle with the destination vector and a zero vector. /// e.g. AND V, <0xffffffff, 0, 0xffffffff, 0>. ==> /// vector_shuffle V, Zero, <0, 4, 2, 4> SDValue DAGCombiner::XformToShuffleWithZero(SDNode *N) { EVT VT = N->getValueType(0); DebugLoc dl = N->getDebugLoc(); SDValue LHS = N->getOperand(0); SDValue RHS = N->getOperand(1); if (N->getOpcode() == ISD::AND) { if (RHS.getOpcode() == ISD::BITCAST) RHS = RHS.getOperand(0); if (RHS.getOpcode() == ISD::BUILD_VECTOR) { SmallVector Indices; unsigned NumElts = RHS.getNumOperands(); for (unsigned i = 0; i != NumElts; ++i) { SDValue Elt = RHS.getOperand(i); if (!isa(Elt)) return SDValue(); else if (cast(Elt)->isAllOnesValue()) Indices.push_back(i); else if (cast(Elt)->isNullValue()) Indices.push_back(NumElts); else return SDValue(); } // Let's see if the target supports this vector_shuffle. EVT RVT = RHS.getValueType(); if (!TLI.isVectorClearMaskLegal(Indices, RVT)) return SDValue(); // Return the new VECTOR_SHUFFLE node. EVT EltVT = RVT.getVectorElementType(); SmallVector ZeroOps(RVT.getVectorNumElements(), DAG.getConstant(0, EltVT)); SDValue Zero = DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), RVT, &ZeroOps[0], ZeroOps.size()); LHS = DAG.getNode(ISD::BITCAST, dl, RVT, LHS); SDValue Shuf = DAG.getVectorShuffle(RVT, dl, LHS, Zero, &Indices[0]); return DAG.getNode(ISD::BITCAST, dl, VT, Shuf); } } return SDValue(); } /// SimplifyVBinOp - Visit a binary vector operation, like ADD. SDValue DAGCombiner::SimplifyVBinOp(SDNode *N) { // After legalize, the target may be depending on adds and other // binary ops to provide legal ways to construct constants or other // things. Simplifying them may result in a loss of legality. if (LegalOperations) return SDValue(); assert(N->getValueType(0).isVector() && "SimplifyVBinOp only works on vectors!"); SDValue LHS = N->getOperand(0); SDValue RHS = N->getOperand(1); SDValue Shuffle = XformToShuffleWithZero(N); if (Shuffle.getNode()) return Shuffle; // If the LHS and RHS are BUILD_VECTOR nodes, see if we can constant fold // this operation. if (LHS.getOpcode() == ISD::BUILD_VECTOR && RHS.getOpcode() == ISD::BUILD_VECTOR) { SmallVector Ops; for (unsigned i = 0, e = LHS.getNumOperands(); i != e; ++i) { SDValue LHSOp = LHS.getOperand(i); SDValue RHSOp = RHS.getOperand(i); // If these two elements can't be folded, bail out. if ((LHSOp.getOpcode() != ISD::UNDEF && LHSOp.getOpcode() != ISD::Constant && LHSOp.getOpcode() != ISD::ConstantFP) || (RHSOp.getOpcode() != ISD::UNDEF && RHSOp.getOpcode() != ISD::Constant && RHSOp.getOpcode() != ISD::ConstantFP)) break; // Can't fold divide by zero. if (N->getOpcode() == ISD::SDIV || N->getOpcode() == ISD::UDIV || N->getOpcode() == ISD::FDIV) { if ((RHSOp.getOpcode() == ISD::Constant && cast(RHSOp.getNode())->isNullValue()) || (RHSOp.getOpcode() == ISD::ConstantFP && cast(RHSOp.getNode())->getValueAPF().isZero())) break; } EVT VT = LHSOp.getValueType(); assert(RHSOp.getValueType() == VT && "SimplifyVBinOp with different BUILD_VECTOR element types"); SDValue FoldOp = DAG.getNode(N->getOpcode(), LHS.getDebugLoc(), VT, LHSOp, RHSOp); if (FoldOp.getOpcode() != ISD::UNDEF && FoldOp.getOpcode() != ISD::Constant && FoldOp.getOpcode() != ISD::ConstantFP) break; Ops.push_back(FoldOp); AddToWorkList(FoldOp.getNode()); } if (Ops.size() == LHS.getNumOperands()) return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), LHS.getValueType(), &Ops[0], Ops.size()); } return SDValue(); } SDValue DAGCombiner::SimplifySelect(DebugLoc DL, SDValue N0, SDValue N1, SDValue N2){ assert(N0.getOpcode() ==ISD::SETCC && "First argument must be a SetCC node!"); SDValue SCC = SimplifySelectCC(DL, N0.getOperand(0), N0.getOperand(1), N1, N2, cast(N0.getOperand(2))->get()); // If we got a simplified select_cc node back from SimplifySelectCC, then // break it down into a new SETCC node, and a new SELECT node, and then return // the SELECT node, since we were called with a SELECT node. if (SCC.getNode()) { // Check to see if we got a select_cc back (to turn into setcc/select). // Otherwise, just return whatever node we got back, like fabs. if (SCC.getOpcode() == ISD::SELECT_CC) { SDValue SETCC = DAG.getNode(ISD::SETCC, N0.getDebugLoc(), N0.getValueType(), SCC.getOperand(0), SCC.getOperand(1), SCC.getOperand(4)); AddToWorkList(SETCC.getNode()); return DAG.getNode(ISD::SELECT, SCC.getDebugLoc(), SCC.getValueType(), SCC.getOperand(2), SCC.getOperand(3), SETCC); } return SCC; } return SDValue(); } /// SimplifySelectOps - Given a SELECT or a SELECT_CC node, where LHS and RHS /// are the two values being selected between, see if we can simplify the /// select. Callers of this should assume that TheSelect is deleted if this /// returns true. As such, they should return the appropriate thing (e.g. the /// node) back to the top-level of the DAG combiner loop to avoid it being /// looked at. bool DAGCombiner::SimplifySelectOps(SDNode *TheSelect, SDValue LHS, SDValue RHS) { // Cannot simplify select with vector condition if (TheSelect->getOperand(0).getValueType().isVector()) return false; // If this is a select from two identical things, try to pull the operation // through the select. if (LHS.getOpcode() != RHS.getOpcode() || !LHS.hasOneUse() || !RHS.hasOneUse()) return false; // If this is a load and the token chain is identical, replace the select // of two loads with a load through a select of the address to load from. // This triggers in things like "select bool X, 10.0, 123.0" after the FP // constants have been dropped into the constant pool. if (LHS.getOpcode() == ISD::LOAD) { LoadSDNode *LLD = cast(LHS); LoadSDNode *RLD = cast(RHS); // Token chains must be identical. if (LHS.getOperand(0) != RHS.getOperand(0) || // Do not let this transformation reduce the number of volatile loads. LLD->isVolatile() || RLD->isVolatile() || // If this is an EXTLOAD, the VT's must match. LLD->getMemoryVT() != RLD->getMemoryVT() || // If this is an EXTLOAD, the kind of extension must match. (LLD->getExtensionType() != RLD->getExtensionType() && // The only exception is if one of the extensions is anyext. LLD->getExtensionType() != ISD::EXTLOAD && RLD->getExtensionType() != ISD::EXTLOAD) || // FIXME: this discards src value information. This is // over-conservative. It would be beneficial to be able to remember // both potential memory locations. Since we are discarding // src value info, don't do the transformation if the memory // locations are not in the default address space. LLD->getPointerInfo().getAddrSpace() != 0 || RLD->getPointerInfo().getAddrSpace() != 0) return false; // Check that the select condition doesn't reach either load. If so, // folding this will induce a cycle into the DAG. If not, this is safe to // xform, so create a select of the addresses. SDValue Addr; if (TheSelect->getOpcode() == ISD::SELECT) { SDNode *CondNode = TheSelect->getOperand(0).getNode(); if ((LLD->hasAnyUseOfValue(1) && LLD->isPredecessorOf(CondNode)) || (RLD->hasAnyUseOfValue(1) && RLD->isPredecessorOf(CondNode))) return false; Addr = DAG.getNode(ISD::SELECT, TheSelect->getDebugLoc(), LLD->getBasePtr().getValueType(), TheSelect->getOperand(0), LLD->getBasePtr(), RLD->getBasePtr()); } else { // Otherwise SELECT_CC SDNode *CondLHS = TheSelect->getOperand(0).getNode(); SDNode *CondRHS = TheSelect->getOperand(1).getNode(); if ((LLD->hasAnyUseOfValue(1) && (LLD->isPredecessorOf(CondLHS) || LLD->isPredecessorOf(CondRHS))) || (LLD->hasAnyUseOfValue(1) && (LLD->isPredecessorOf(CondLHS) || LLD->isPredecessorOf(CondRHS)))) return false; Addr = DAG.getNode(ISD::SELECT_CC, TheSelect->getDebugLoc(), LLD->getBasePtr().getValueType(), TheSelect->getOperand(0), TheSelect->getOperand(1), LLD->getBasePtr(), RLD->getBasePtr(), TheSelect->getOperand(4)); } SDValue Load; if (LLD->getExtensionType() == ISD::NON_EXTLOAD) { Load = DAG.getLoad(TheSelect->getValueType(0), TheSelect->getDebugLoc(), // FIXME: Discards pointer info. LLD->getChain(), Addr, MachinePointerInfo(), LLD->isVolatile(), LLD->isNonTemporal(), LLD->getAlignment()); } else { Load = DAG.getExtLoad(LLD->getExtensionType() == ISD::EXTLOAD ? RLD->getExtensionType() : LLD->getExtensionType(), TheSelect->getDebugLoc(), TheSelect->getValueType(0), // FIXME: Discards pointer info. LLD->getChain(), Addr, MachinePointerInfo(), LLD->getMemoryVT(), LLD->isVolatile(), LLD->isNonTemporal(), LLD->getAlignment()); } // Users of the select now use the result of the load. CombineTo(TheSelect, Load); // Users of the old loads now use the new load's chain. We know the // old-load value is dead now. CombineTo(LHS.getNode(), Load.getValue(0), Load.getValue(1)); CombineTo(RHS.getNode(), Load.getValue(0), Load.getValue(1)); return true; } return false; } /// SimplifySelectCC - Simplify an expression of the form (N0 cond N1) ? N2 : N3 /// where 'cond' is the comparison specified by CC. SDValue DAGCombiner::SimplifySelectCC(DebugLoc DL, SDValue N0, SDValue N1, SDValue N2, SDValue N3, ISD::CondCode CC, bool NotExtCompare) { // (x ? y : y) -> y. if (N2 == N3) return N2; EVT VT = N2.getValueType(); ConstantSDNode *N1C = dyn_cast(N1.getNode()); ConstantSDNode *N2C = dyn_cast(N2.getNode()); ConstantSDNode *N3C = dyn_cast(N3.getNode()); // Determine if the condition we're dealing with is constant SDValue SCC = SimplifySetCC(TLI.getSetCCResultType(N0.getValueType()), N0, N1, CC, DL, false); if (SCC.getNode()) AddToWorkList(SCC.getNode()); ConstantSDNode *SCCC = dyn_cast_or_null(SCC.getNode()); // fold select_cc true, x, y -> x if (SCCC && !SCCC->isNullValue()) return N2; // fold select_cc false, x, y -> y if (SCCC && SCCC->isNullValue()) return N3; // Check to see if we can simplify the select into an fabs node if (ConstantFPSDNode *CFP = dyn_cast(N1)) { // Allow either -0.0 or 0.0 if (CFP->getValueAPF().isZero()) { // select (setg[te] X, +/-0.0), X, fneg(X) -> fabs if ((CC == ISD::SETGE || CC == ISD::SETGT) && N0 == N2 && N3.getOpcode() == ISD::FNEG && N2 == N3.getOperand(0)) return DAG.getNode(ISD::FABS, DL, VT, N0); // select (setl[te] X, +/-0.0), fneg(X), X -> fabs if ((CC == ISD::SETLT || CC == ISD::SETLE) && N0 == N3 && N2.getOpcode() == ISD::FNEG && N2.getOperand(0) == N3) return DAG.getNode(ISD::FABS, DL, VT, N3); } } // Turn "(a cond b) ? 1.0f : 2.0f" into "load (tmp + ((a cond b) ? 0 : 4)" // where "tmp" is a constant pool entry containing an array with 1.0 and 2.0 // in it. This is a win when the constant is not otherwise available because // it replaces two constant pool loads with one. We only do this if the FP // type is known to be legal, because if it isn't, then we are before legalize // types an we want the other legalization to happen first (e.g. to avoid // messing with soft float) and if the ConstantFP is not legal, because if // it is legal, we may not need to store the FP constant in a constant pool. if (ConstantFPSDNode *TV = dyn_cast(N2)) if (ConstantFPSDNode *FV = dyn_cast(N3)) { if (TLI.isTypeLegal(N2.getValueType()) && (TLI.getOperationAction(ISD::ConstantFP, N2.getValueType()) != TargetLowering::Legal) && // If both constants have multiple uses, then we won't need to do an // extra load, they are likely around in registers for other users. (TV->hasOneUse() || FV->hasOneUse())) { Constant *Elts[] = { const_cast(FV->getConstantFPValue()), const_cast(TV->getConstantFPValue()) }; const Type *FPTy = Elts[0]->getType(); const TargetData &TD = *TLI.getTargetData(); // Create a ConstantArray of the two constants. Constant *CA = ConstantArray::get(ArrayType::get(FPTy, 2), Elts, 2); SDValue CPIdx = DAG.getConstantPool(CA, TLI.getPointerTy(), TD.getPrefTypeAlignment(FPTy)); unsigned Alignment = cast(CPIdx)->getAlignment(); // Get the offsets to the 0 and 1 element of the array so that we can // select between them. SDValue Zero = DAG.getIntPtrConstant(0); unsigned EltSize = (unsigned)TD.getTypeAllocSize(Elts[0]->getType()); SDValue One = DAG.getIntPtrConstant(EltSize); SDValue Cond = DAG.getSetCC(DL, TLI.getSetCCResultType(N0.getValueType()), N0, N1, CC); SDValue CstOffset = DAG.getNode(ISD::SELECT, DL, Zero.getValueType(), Cond, One, Zero); CPIdx = DAG.getNode(ISD::ADD, DL, TLI.getPointerTy(), CPIdx, CstOffset); return DAG.getLoad(TV->getValueType(0), DL, DAG.getEntryNode(), CPIdx, MachinePointerInfo::getConstantPool(), false, false, Alignment); } } // Check to see if we can perform the "gzip trick", transforming // (select_cc setlt X, 0, A, 0) -> (and (sra X, (sub size(X), 1), A) if (N1C && N3C && N3C->isNullValue() && CC == ISD::SETLT && N0.getValueType().isInteger() && N2.getValueType().isInteger() && (N1C->isNullValue() || // (a < 0) ? b : 0 (N1C->getAPIntValue() == 1 && N0 == N2))) { // (a < 1) ? a : 0 EVT XType = N0.getValueType(); EVT AType = N2.getValueType(); if (XType.bitsGE(AType)) { // and (sra X, size(X)-1, A) -> "and (srl X, C2), A" iff A is a // single-bit constant. if (N2C && ((N2C->getAPIntValue() & (N2C->getAPIntValue()-1)) == 0)) { unsigned ShCtV = N2C->getAPIntValue().logBase2(); ShCtV = XType.getSizeInBits()-ShCtV-1; SDValue ShCt = DAG.getConstant(ShCtV, getShiftAmountTy(N0.getValueType())); SDValue Shift = DAG.getNode(ISD::SRL, N0.getDebugLoc(), XType, N0, ShCt); AddToWorkList(Shift.getNode()); if (XType.bitsGT(AType)) { Shift = DAG.getNode(ISD::TRUNCATE, DL, AType, Shift); AddToWorkList(Shift.getNode()); } return DAG.getNode(ISD::AND, DL, AType, Shift, N2); } SDValue Shift = DAG.getNode(ISD::SRA, N0.getDebugLoc(), XType, N0, DAG.getConstant(XType.getSizeInBits()-1, getShiftAmountTy(N0.getValueType()))); AddToWorkList(Shift.getNode()); if (XType.bitsGT(AType)) { Shift = DAG.getNode(ISD::TRUNCATE, DL, AType, Shift); AddToWorkList(Shift.getNode()); } return DAG.getNode(ISD::AND, DL, AType, Shift, N2); } } // fold (select_cc seteq (and x, y), 0, 0, A) -> (and (shr (shl x)) A) // where y is has a single bit set. // A plaintext description would be, we can turn the SELECT_CC into an AND // when the condition can be materialized as an all-ones register. Any // single bit-test can be materialized as an all-ones register with // shift-left and shift-right-arith. if (CC == ISD::SETEQ && N0->getOpcode() == ISD::AND && N0->getValueType(0) == VT && N1C && N1C->isNullValue() && N2C && N2C->isNullValue()) { SDValue AndLHS = N0->getOperand(0); ConstantSDNode *ConstAndRHS = dyn_cast(N0->getOperand(1)); if (ConstAndRHS && ConstAndRHS->getAPIntValue().countPopulation() == 1) { // Shift the tested bit over the sign bit. APInt AndMask = ConstAndRHS->getAPIntValue(); SDValue ShlAmt = DAG.getConstant(AndMask.countLeadingZeros(), getShiftAmountTy(AndLHS.getValueType())); SDValue Shl = DAG.getNode(ISD::SHL, N0.getDebugLoc(), VT, AndLHS, ShlAmt); // Now arithmetic right shift it all the way over, so the result is either // all-ones, or zero. SDValue ShrAmt = DAG.getConstant(AndMask.getBitWidth()-1, getShiftAmountTy(Shl.getValueType())); SDValue Shr = DAG.getNode(ISD::SRA, N0.getDebugLoc(), VT, Shl, ShrAmt); return DAG.getNode(ISD::AND, DL, VT, Shr, N3); } } // fold select C, 16, 0 -> shl C, 4 if (N2C && N3C && N3C->isNullValue() && N2C->getAPIntValue().isPowerOf2() && TLI.getBooleanContents() == TargetLowering::ZeroOrOneBooleanContent) { // If the caller doesn't want us to simplify this into a zext of a compare, // don't do it. if (NotExtCompare && N2C->getAPIntValue() == 1) return SDValue(); // Get a SetCC of the condition // FIXME: Should probably make sure that setcc is legal if we ever have a // target where it isn't. SDValue Temp, SCC; // cast from setcc result type to select result type if (LegalTypes) { SCC = DAG.getSetCC(DL, TLI.getSetCCResultType(N0.getValueType()), N0, N1, CC); if (N2.getValueType().bitsLT(SCC.getValueType())) Temp = DAG.getZeroExtendInReg(SCC, N2.getDebugLoc(), N2.getValueType()); else Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getDebugLoc(), N2.getValueType(), SCC); } else { SCC = DAG.getSetCC(N0.getDebugLoc(), MVT::i1, N0, N1, CC); Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getDebugLoc(), N2.getValueType(), SCC); } AddToWorkList(SCC.getNode()); AddToWorkList(Temp.getNode()); if (N2C->getAPIntValue() == 1) return Temp; // shl setcc result by log2 n2c return DAG.getNode(ISD::SHL, DL, N2.getValueType(), Temp, DAG.getConstant(N2C->getAPIntValue().logBase2(), getShiftAmountTy(Temp.getValueType()))); } // Check to see if this is the equivalent of setcc // FIXME: Turn all of these into setcc if setcc if setcc is legal // otherwise, go ahead with the folds. if (0 && N3C && N3C->isNullValue() && N2C && (N2C->getAPIntValue() == 1ULL)) { EVT XType = N0.getValueType(); if (!LegalOperations || TLI.isOperationLegal(ISD::SETCC, TLI.getSetCCResultType(XType))) { SDValue Res = DAG.getSetCC(DL, TLI.getSetCCResultType(XType), N0, N1, CC); if (Res.getValueType() != VT) Res = DAG.getNode(ISD::ZERO_EXTEND, DL, VT, Res); return Res; } // fold (seteq X, 0) -> (srl (ctlz X, log2(size(X)))) if (N1C && N1C->isNullValue() && CC == ISD::SETEQ && (!LegalOperations || TLI.isOperationLegal(ISD::CTLZ, XType))) { SDValue Ctlz = DAG.getNode(ISD::CTLZ, N0.getDebugLoc(), XType, N0); return DAG.getNode(ISD::SRL, DL, XType, Ctlz, DAG.getConstant(Log2_32(XType.getSizeInBits()), getShiftAmountTy(Ctlz.getValueType()))); } // fold (setgt X, 0) -> (srl (and (-X, ~X), size(X)-1)) if (N1C && N1C->isNullValue() && CC == ISD::SETGT) { SDValue NegN0 = DAG.getNode(ISD::SUB, N0.getDebugLoc(), XType, DAG.getConstant(0, XType), N0); SDValue NotN0 = DAG.getNOT(N0.getDebugLoc(), N0, XType); return DAG.getNode(ISD::SRL, DL, XType, DAG.getNode(ISD::AND, DL, XType, NegN0, NotN0), DAG.getConstant(XType.getSizeInBits()-1, getShiftAmountTy(XType))); } // fold (setgt X, -1) -> (xor (srl (X, size(X)-1), 1)) if (N1C && N1C->isAllOnesValue() && CC == ISD::SETGT) { SDValue Sign = DAG.getNode(ISD::SRL, N0.getDebugLoc(), XType, N0, DAG.getConstant(XType.getSizeInBits()-1, getShiftAmountTy(N0.getValueType()))); return DAG.getNode(ISD::XOR, DL, XType, Sign, DAG.getConstant(1, XType)); } } // Check to see if this is an integer abs. // select_cc setg[te] X, 0, X, -X -> // select_cc setgt X, -1, X, -X -> // select_cc setl[te] X, 0, -X, X -> // select_cc setlt X, 1, -X, X -> // Y = sra (X, size(X)-1); xor (add (X, Y), Y) if (N1C) { ConstantSDNode *SubC = NULL; if (((N1C->isNullValue() && (CC == ISD::SETGT || CC == ISD::SETGE)) || (N1C->isAllOnesValue() && CC == ISD::SETGT)) && N0 == N2 && N3.getOpcode() == ISD::SUB && N0 == N3.getOperand(1)) SubC = dyn_cast(N3.getOperand(0)); else if (((N1C->isNullValue() && (CC == ISD::SETLT || CC == ISD::SETLE)) || (N1C->isOne() && CC == ISD::SETLT)) && N0 == N3 && N2.getOpcode() == ISD::SUB && N0 == N2.getOperand(1)) SubC = dyn_cast(N2.getOperand(0)); EVT XType = N0.getValueType(); if (SubC && SubC->isNullValue() && XType.isInteger()) { SDValue Shift = DAG.getNode(ISD::SRA, N0.getDebugLoc(), XType, N0, DAG.getConstant(XType.getSizeInBits()-1, getShiftAmountTy(N0.getValueType()))); SDValue Add = DAG.getNode(ISD::ADD, N0.getDebugLoc(), XType, N0, Shift); AddToWorkList(Shift.getNode()); AddToWorkList(Add.getNode()); return DAG.getNode(ISD::XOR, DL, XType, Add, Shift); } } return SDValue(); } /// SimplifySetCC - This is a stub for TargetLowering::SimplifySetCC. SDValue DAGCombiner::SimplifySetCC(EVT VT, SDValue N0, SDValue N1, ISD::CondCode Cond, DebugLoc DL, bool foldBooleans) { TargetLowering::DAGCombinerInfo DagCombineInfo(DAG, !LegalTypes, !LegalOperations, false, this); return TLI.SimplifySetCC(VT, N0, N1, Cond, foldBooleans, DagCombineInfo, DL); } /// BuildSDIVSequence - Given an ISD::SDIV node expressing a divide by constant, /// return a DAG expression to select that will generate the same value by /// multiplying by a magic number. See: /// SDValue DAGCombiner::BuildSDIV(SDNode *N) { std::vector Built; SDValue S = TLI.BuildSDIV(N, DAG, &Built); for (std::vector::iterator ii = Built.begin(), ee = Built.end(); ii != ee; ++ii) AddToWorkList(*ii); return S; } /// BuildUDIVSequence - Given an ISD::UDIV node expressing a divide by constant, /// return a DAG expression to select that will generate the same value by /// multiplying by a magic number. See: /// SDValue DAGCombiner::BuildUDIV(SDNode *N) { std::vector Built; SDValue S = TLI.BuildUDIV(N, DAG, &Built); for (std::vector::iterator ii = Built.begin(), ee = Built.end(); ii != ee; ++ii) AddToWorkList(*ii); return S; } /// FindBaseOffset - Return true if base is a frame index, which is known not // to alias with anything but itself. Provides base object and offset as // results. static bool FindBaseOffset(SDValue Ptr, SDValue &Base, int64_t &Offset, const GlobalValue *&GV, void *&CV) { // Assume it is a primitive operation. Base = Ptr; Offset = 0; GV = 0; CV = 0; // If it's an adding a simple constant then integrate the offset. if (Base.getOpcode() == ISD::ADD) { if (ConstantSDNode *C = dyn_cast(Base.getOperand(1))) { Base = Base.getOperand(0); Offset += C->getZExtValue(); } } // Return the underlying GlobalValue, and update the Offset. Return false // for GlobalAddressSDNode since the same GlobalAddress may be represented // by multiple nodes with different offsets. if (GlobalAddressSDNode *G = dyn_cast(Base)) { GV = G->getGlobal(); Offset += G->getOffset(); return false; } // Return the underlying Constant value, and update the Offset. Return false // for ConstantSDNodes since the same constant pool entry may be represented // by multiple nodes with different offsets. if (ConstantPoolSDNode *C = dyn_cast(Base)) { CV = C->isMachineConstantPoolEntry() ? (void *)C->getMachineCPVal() : (void *)C->getConstVal(); Offset += C->getOffset(); return false; } // If it's any of the following then it can't alias with anything but itself. return isa(Base); } /// isAlias - Return true if there is any possibility that the two addresses /// overlap. bool DAGCombiner::isAlias(SDValue Ptr1, int64_t Size1, const Value *SrcValue1, int SrcValueOffset1, unsigned SrcValueAlign1, const MDNode *TBAAInfo1, SDValue Ptr2, int64_t Size2, const Value *SrcValue2, int SrcValueOffset2, unsigned SrcValueAlign2, const MDNode *TBAAInfo2) const { // If they are the same then they must be aliases. if (Ptr1 == Ptr2) return true; // Gather base node and offset information. SDValue Base1, Base2; int64_t Offset1, Offset2; const GlobalValue *GV1, *GV2; void *CV1, *CV2; bool isFrameIndex1 = FindBaseOffset(Ptr1, Base1, Offset1, GV1, CV1); bool isFrameIndex2 = FindBaseOffset(Ptr2, Base2, Offset2, GV2, CV2); // If they have a same base address then check to see if they overlap. if (Base1 == Base2 || (GV1 && (GV1 == GV2)) || (CV1 && (CV1 == CV2))) return !((Offset1 + Size1) <= Offset2 || (Offset2 + Size2) <= Offset1); // It is possible for different frame indices to alias each other, mostly // when tail call optimization reuses return address slots for arguments. // To catch this case, look up the actual index of frame indices to compute // the real alias relationship. if (isFrameIndex1 && isFrameIndex2) { MachineFrameInfo *MFI = DAG.getMachineFunction().getFrameInfo(); Offset1 += MFI->getObjectOffset(cast(Base1)->getIndex()); Offset2 += MFI->getObjectOffset(cast(Base2)->getIndex()); return !((Offset1 + Size1) <= Offset2 || (Offset2 + Size2) <= Offset1); } // Otherwise, if we know what the bases are, and they aren't identical, then // we know they cannot alias. if ((isFrameIndex1 || CV1 || GV1) && (isFrameIndex2 || CV2 || GV2)) return false; // If we know required SrcValue1 and SrcValue2 have relatively large alignment // compared to the size and offset of the access, we may be able to prove they // do not alias. This check is conservative for now to catch cases created by // splitting vector types. if ((SrcValueAlign1 == SrcValueAlign2) && (SrcValueOffset1 != SrcValueOffset2) && (Size1 == Size2) && (SrcValueAlign1 > Size1)) { int64_t OffAlign1 = SrcValueOffset1 % SrcValueAlign1; int64_t OffAlign2 = SrcValueOffset2 % SrcValueAlign1; // There is no overlap between these relatively aligned accesses of similar // size, return no alias. if ((OffAlign1 + Size1) <= OffAlign2 || (OffAlign2 + Size2) <= OffAlign1) return false; } if (CombinerGlobalAA) { // Use alias analysis information. int64_t MinOffset = std::min(SrcValueOffset1, SrcValueOffset2); int64_t Overlap1 = Size1 + SrcValueOffset1 - MinOffset; int64_t Overlap2 = Size2 + SrcValueOffset2 - MinOffset; AliasAnalysis::AliasResult AAResult = AA.alias(AliasAnalysis::Location(SrcValue1, Overlap1, TBAAInfo1), AliasAnalysis::Location(SrcValue2, Overlap2, TBAAInfo2)); if (AAResult == AliasAnalysis::NoAlias) return false; } // Otherwise we have to assume they alias. return true; } /// FindAliasInfo - Extracts the relevant alias information from the memory /// node. Returns true if the operand was a load. bool DAGCombiner::FindAliasInfo(SDNode *N, SDValue &Ptr, int64_t &Size, const Value *&SrcValue, int &SrcValueOffset, unsigned &SrcValueAlign, const MDNode *&TBAAInfo) const { if (LoadSDNode *LD = dyn_cast(N)) { Ptr = LD->getBasePtr(); Size = LD->getMemoryVT().getSizeInBits() >> 3; SrcValue = LD->getSrcValue(); SrcValueOffset = LD->getSrcValueOffset(); SrcValueAlign = LD->getOriginalAlignment(); TBAAInfo = LD->getTBAAInfo(); return true; } else if (StoreSDNode *ST = dyn_cast(N)) { Ptr = ST->getBasePtr(); Size = ST->getMemoryVT().getSizeInBits() >> 3; SrcValue = ST->getSrcValue(); SrcValueOffset = ST->getSrcValueOffset(); SrcValueAlign = ST->getOriginalAlignment(); TBAAInfo = ST->getTBAAInfo(); } else { llvm_unreachable("FindAliasInfo expected a memory operand"); } return false; } /// GatherAllAliases - Walk up chain skipping non-aliasing memory nodes, /// looking for aliasing nodes and adding them to the Aliases vector. void DAGCombiner::GatherAllAliases(SDNode *N, SDValue OriginalChain, SmallVector &Aliases) { SmallVector Chains; // List of chains to visit. SmallPtrSet Visited; // Visited node set. // Get alias information for node. SDValue Ptr; int64_t Size; const Value *SrcValue; int SrcValueOffset; unsigned SrcValueAlign; const MDNode *SrcTBAAInfo; bool IsLoad = FindAliasInfo(N, Ptr, Size, SrcValue, SrcValueOffset, SrcValueAlign, SrcTBAAInfo); // Starting off. Chains.push_back(OriginalChain); unsigned Depth = 0; // Look at each chain and determine if it is an alias. If so, add it to the // aliases list. If not, then continue up the chain looking for the next // candidate. while (!Chains.empty()) { SDValue Chain = Chains.back(); Chains.pop_back(); // For TokenFactor nodes, look at each operand and only continue up the // chain until we find two aliases. If we've seen two aliases, assume we'll // find more and revert to original chain since the xform is unlikely to be // profitable. // // FIXME: The depth check could be made to return the last non-aliasing // chain we found before we hit a tokenfactor rather than the original // chain. if (Depth > 6 || Aliases.size() == 2) { Aliases.clear(); Aliases.push_back(OriginalChain); break; } // Don't bother if we've been before. if (!Visited.insert(Chain.getNode())) continue; switch (Chain.getOpcode()) { case ISD::EntryToken: // Entry token is ideal chain operand, but handled in FindBetterChain. break; case ISD::LOAD: case ISD::STORE: { // Get alias information for Chain. SDValue OpPtr; int64_t OpSize; const Value *OpSrcValue; int OpSrcValueOffset; unsigned OpSrcValueAlign; const MDNode *OpSrcTBAAInfo; bool IsOpLoad = FindAliasInfo(Chain.getNode(), OpPtr, OpSize, OpSrcValue, OpSrcValueOffset, OpSrcValueAlign, OpSrcTBAAInfo); // If chain is alias then stop here. if (!(IsLoad && IsOpLoad) && isAlias(Ptr, Size, SrcValue, SrcValueOffset, SrcValueAlign, SrcTBAAInfo, OpPtr, OpSize, OpSrcValue, OpSrcValueOffset, OpSrcValueAlign, OpSrcTBAAInfo)) { Aliases.push_back(Chain); } else { // Look further up the chain. Chains.push_back(Chain.getOperand(0)); ++Depth; } break; } case ISD::TokenFactor: // We have to check each of the operands of the token factor for "small" // token factors, so we queue them up. Adding the operands to the queue // (stack) in reverse order maintains the original order and increases the // likelihood that getNode will find a matching token factor (CSE.) if (Chain.getNumOperands() > 16) { Aliases.push_back(Chain); break; } for (unsigned n = Chain.getNumOperands(); n;) Chains.push_back(Chain.getOperand(--n)); ++Depth; break; default: // For all other instructions we will just have to take what we can get. Aliases.push_back(Chain); break; } } } /// FindBetterChain - Walk up chain skipping non-aliasing memory nodes, looking /// for a better chain (aliasing node.) SDValue DAGCombiner::FindBetterChain(SDNode *N, SDValue OldChain) { SmallVector Aliases; // Ops for replacing token factor. // Accumulate all the aliases to this node. GatherAllAliases(N, OldChain, Aliases); if (Aliases.size() == 0) { // If no operands then chain to entry token. return DAG.getEntryNode(); } else if (Aliases.size() == 1) { // If a single operand then chain to it. We don't need to revisit it. return Aliases[0]; } // Construct a custom tailored token factor. return DAG.getNode(ISD::TokenFactor, N->getDebugLoc(), MVT::Other, &Aliases[0], Aliases.size()); } // SelectionDAG::Combine - This is the entry point for the file. // void SelectionDAG::Combine(CombineLevel Level, AliasAnalysis &AA, CodeGenOpt::Level OptLevel) { /// run - This is the main entry point to this class. /// DAGCombiner(*this, AA, OptLevel).Run(Level); }