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Diffstat (limited to 'contrib/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp')
| -rw-r--r-- | contrib/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 7222 |
1 files changed, 7222 insertions, 0 deletions
diff --git a/contrib/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/contrib/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp new file mode 100644 index 000000000000..c9c4d91e9736 --- /dev/null +++ b/contrib/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -0,0 +1,7222 @@ +//===-- 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/TargetFrameInfo.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 <algorithm> +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"); + +namespace { + static cl::opt<bool> + CombinerAA("combiner-alias-analysis", cl::Hidden, + cl::desc("Turn on alias analysis during testing")); + + static cl::opt<bool> + 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<SDNode*> 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 visitBIT_CONVERT(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 ConstantFoldBIT_CONVERTofBUILD_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 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<SDValue, 8> &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, + SDValue Ptr2, int64_t Size2, + const Value *SrcValue2, int SrcValueOffset2, + unsigned SrcValueAlign2) 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; + + /// 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() { + return LegalTypes ? TLI.getShiftAmountTy() : 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<SDValue> &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<ConstantFPSDNode>(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<ConstantFPSDNode>(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<ConstantSDNode>(N.getOperand(2))->getAPIntValue() == 1 && + cast<ConstantSDNode>(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<ConstantSDNode>(N0.getOperand(1))) { + if (isa<ConstantSDNode>(N1)) { + // reassoc. (op (op x, c1), c2) -> (op x, (op c1, c2)) + SDValue OpNode = + DAG.FoldConstantArithmetic(Opc, VT, + cast<ConstantSDNode>(N0.getOperand(1)), + cast<ConstantSDNode>(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<ConstantSDNode>(N1.getOperand(1))) { + if (isa<ConstantSDNode>(N0)) { + // reassoc. (op c2, (op x, c1)) -> (op x, (op c1, c2)) + SDValue OpNode = + DAG.FoldConstantArithmetic(Opc, VT, + cast<ConstantSDNode>(N1.getOperand(1)), + cast<ConstantSDNode>(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<LoadSDNode>(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, PVT, dl, + LD->getChain(), LD->getBasePtr(), + LD->getSrcValue(), LD->getSrcValueOffset(), + 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<LoadSDNode>(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, PVT, dl, + LD->getChain(), LD->getBasePtr(), + LD->getSrcValue(), LD->getSrcValueOffset(), + 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::BIT_CONVERT: return visitBIT_CONVERT(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<ConstantSDNode>(N0) || !isa<ConstantSDNode>(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<SDNode *, 8> TFs; // List of token factors to visit. + SmallVector<SDValue, 8> Ops; // Ops for replacing token factor. + SmallPtrSet<SDNode*, 16> 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<ConstantSDNode>(N01); + + if (N01C && N00.getOpcode() == ISD::ADD && N00.getNode()->hasOneUse() && + isa<ConstantSDNode>(N00.getOperand(1))) { + // fold (add (shl (add x, c1), c2), ) -> (add (add (shl x, c2), c1<<c2), ) + N0 = DAG.getNode(ISD::ADD, N0.getDebugLoc(), VT, + DAG.getNode(ISD::SHL, N00.getDebugLoc(), VT, + N00.getOperand(0), N01), + DAG.getNode(ISD::SHL, N01.getDebugLoc(), VT, + N00.getOperand(1), N01)); + return DAG.getNode(ISD::ADD, DL, VT, N0, N1); + } + + return SDValue(); +} + +SDValue DAGCombiner::visitADD(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); + ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(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<GlobalAddressSDNode>(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<ConstantSDNode>(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<ConstantSDNode>(N0.getOperand(0)) && + cast<ConstantSDNode>(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<ConstantSDNode>(N1.getOperand(0)) && + cast<ConstantSDNode>(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<ConstantSDNode>(N00) || isa<ConstantSDNode>(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<<c2), ) + if (N0.getOpcode() == ISD::SHL && N0.getNode()->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<ConstantSDNode>(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<ConstantSDNode>(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))); + + return SDValue(); +} + +SDValue DAGCombiner::visitADDC(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); + ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(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::Flag)); + + // 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::Flag)); + + // 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::Flag)); + } + + 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<ConstantSDNode>(N0); + ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); + + // 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(); +} + +SDValue DAGCombiner::visitSUB(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getNode()); + ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(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 + if (N0 == N1) + return DAG.getConstant(0, N->getValueType(0)); + // 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+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<GlobalAddressSDNode>(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<GlobalAddressSDNode>(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<ConstantSDNode>(N0); + ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(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())); + // 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()))); + } + // (mul (shl X, c1), c2) -> (mul X, c2 << c1) + if (N1C && N0.getOpcode() == ISD::SHL && + isa<ConstantSDNode>(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<ConstantSDNode>(N0.getOperand(1)) && + N0.getNode()->hasOneUse()) { + Sh = N0; Y = N1; + } else if (N1.getOpcode() == ISD::SHL && + isa<ConstantSDNode>(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<ConstantSDNode>(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<ConstantSDNode>(N0.getNode()); + ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(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())); + 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())); + 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())); + + // 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<ConstantSDNode>(N0.getNode()); + ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(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())); + // 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<ConstantSDNode>(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<ConstantSDNode>(N0); + ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(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<ConstantSDNode>(N0); + ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(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<ConstantSDNode>(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<ConstantSDNode>(N1); + EVT VT = N->getValueType(0); + + // 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())); + // fold (mulhs x, undef) -> 0 + if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF) + return DAG.getConstant(0, VT); + + return SDValue(); +} + +SDValue DAGCombiner::visitMULHU(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); + EVT VT = N->getValueType(0); + + // 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); + + 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; + + return SDValue(); +} + +SDValue DAGCombiner::visitUMUL_LOHI(SDNode *N) { + SDValue Res = SimplifyNodeWithTwoResults(N, ISD::MUL, ISD::MULHU); + if (Res.getNode()) return Res; + + 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<ConstantSDNode>(N0); + ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(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<ConstantSDNode>(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.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<CondCodeSDNode>(CC0)->get(); + ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get(); + + if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 && + LL.getValueType().isInteger()) { + // fold (and (seteq X, 0), (seteq Y, 0)) -> (seteq (or X, Y), 0) + if (cast<ConstantSDNode>(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<ConstantSDNode>(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<ConstantSDNode>(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<LoadSDNode>(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, VT, N0.getDebugLoc(), + LN0->getChain(), LN0->getBasePtr(), + LN0->getSrcValue(), + LN0->getSrcValueOffset(), 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<LoadSDNode>(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, VT, N0.getDebugLoc(), + LN0->getChain(), + LN0->getBasePtr(), LN0->getSrcValue(), + LN0->getSrcValueOffset(), 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<LoadSDNode>(N0.getOperand(0)) + : cast<LoadSDNode>(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, LoadResultTy, LN0->getDebugLoc(), + LN0->getChain(), LN0->getBasePtr(), + LN0->getSrcValue(), LN0->getSrcValueOffset(), + 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, LoadResultTy, LN0->getDebugLoc(), + LN0->getChain(), NewPtr, + LN0->getSrcValue(), LN0->getSrcValueOffset(), + 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<ConstantSDNode>(N0); + ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(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<ConstantSDNode>(N0.getOperand(1))) { + ConstantSDNode *C1 = cast<ConstantSDNode>(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<CondCodeSDNode>(CC0)->get(); + ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get(); + + if (LR == RR && isa<ConstantSDNode>(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<ConstantSDNode>(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<ConstantSDNode>(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<ConstantSDNode>(N0.getOperand(1))->getAPIntValue(); + const APInt &RHSMask = + cast<ConstantSDNode>(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<ConstantSDNode>(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<ConstantSDNode>(LHSShiftAmt)->getZExtValue(); + uint64_t RShVal = cast<ConstantSDNode>(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<ConstantSDNode>(LHSMask)->getAPIntValue() | RHSBits; + } + if (RHSMask.getNode()) { + APInt LHSBits = APInt::getHighBitsSet(OpSizeInBits, RShVal); + Mask &= cast<ConstantSDNode>(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<ConstantSDNode>(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<ConstantSDNode>(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<ConstantSDNode>(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<ConstantSDNode>(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<ConstantSDNode>(N0); + ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(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<CondCodeSDNode>(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<ConstantSDNode>(RHS) || isa<ConstantSDNode>(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<ConstantSDNode>(N0.getOperand(0)); + ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(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) { + 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<SDValue> Ops(VT.getVectorNumElements(), El); + return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), VT, + &Ops[0], Ops.size()); + } + } + + // 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<ConstantSDNode>(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<ConstantSDNode>(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<ConstantSDNode>(N0); + ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); + EVT VT = N0.getValueType(); + unsigned OpSizeInBits = VT.getScalarType().getSizeInBits(); + + // fold (shl c1, c2) -> c1<<c2 + if (N0C && N1C) + return DAG.FoldConstantArithmetic(ISD::SHL, VT, N0C, N1C); + // fold (shl 0, x) -> 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<ConstantSDNode>(N101)) { + EVT TruncVT = N1.getValueType(); + SDValue N100 = N1.getOperand(0).getOperand(0); + APInt TruncC = N101C->getAPIntValue(); + 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<ConstantSDNode>(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 (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<ConstantSDNode>(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<ConstantSDNode>(N0); + ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(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<ConstantSDNode>(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<ConstantSDNode>(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()); + 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<ConstantSDNode>(N101)) { + EVT TruncVT = N1.getValueType(); + SDValue N100 = N1.getOperand(0).getOperand(0); + APInt TruncC = N101C->getAPIntValue(); + 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))); + } + } + + // 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<ConstantSDNode>(N0); + ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(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<ConstantSDNode>(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 (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())); + 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<ConstantSDNode>(N101)) { + EVT TruncVT = N1.getValueType(); + SDValue N100 = N1.getOperand(0).getOperand(0); + APInt TruncC = N101C->getAPIntValue(); + 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<ConstantSDNode>(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<ConstantSDNode>(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<ConstantSDNode>(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<ConstantSDNode>(N0); + ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); + ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(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<CondCodeSDNode>(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<ConstantSDNode>(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<CondCodeSDNode>(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<SDNode*, 4> &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<CondCodeSDNode>(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<ConstantSDNode>(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 + // good a 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<ConstantSDNode>(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))) + if (ISD::isNON_EXTLoad(N0.getNode()) && + ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || + TLI.isLoadExtLegal(ISD::SEXTLOAD, N0.getValueType()))) { + bool DoXform = true; + SmallVector<SDNode*, 4> SetCCs; + if (!N0.hasOneUse()) + DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::SIGN_EXTEND, SetCCs, TLI); + if (DoXform) { + LoadSDNode *LN0 = cast<LoadSDNode>(N0); + SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N->getDebugLoc(), + LN0->getChain(), + LN0->getBasePtr(), LN0->getSrcValue(), + LN0->getSrcValueOffset(), + 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<SDValue, 4> 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<LoadSDNode>(N0); + EVT MemVT = LN0->getMemoryVT(); + if ((!LegalOperations && !LN0->isVolatile()) || + TLI.isLoadExtLegal(ISD::SEXTLOAD, MemVT)) { + SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N->getDebugLoc(), + LN0->getChain(), + LN0->getBasePtr(), LN0->getSrcValue(), + LN0->getSrcValueOffset(), 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<CondCodeSDNode>(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<CondCodeSDNode>(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<CondCodeSDNode>(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<CondCodeSDNode>(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<ConstantSDNode>(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))) { + 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<ConstantSDNode>(N0.getOperand(1))->getAPIntValue(); + 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))) + if (ISD::isNON_EXTLoad(N0.getNode()) && + ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || + TLI.isLoadExtLegal(ISD::ZEXTLOAD, N0.getValueType()))) { + bool DoXform = true; + SmallVector<SDNode*, 4> SetCCs; + if (!N0.hasOneUse()) + DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::ZERO_EXTEND, SetCCs, TLI); + if (DoXform) { + LoadSDNode *LN0 = cast<LoadSDNode>(N0); + SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, N->getDebugLoc(), + LN0->getChain(), + LN0->getBasePtr(), LN0->getSrcValue(), + LN0->getSrcValueOffset(), + 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<SDValue, 4> 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<LoadSDNode>(N0); + EVT MemVT = LN0->getMemoryVT(); + if ((!LegalOperations && !LN0->isVolatile()) || + TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT)) { + SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, N->getDebugLoc(), + LN0->getChain(), + LN0->getBasePtr(), LN0->getSrcValue(), + LN0->getSrcValueOffset(), 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<SDValue,8> 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<CondCodeSDNode>(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<CondCodeSDNode>(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<CondCodeSDNode>(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<ConstantSDNode>(N0.getOperand(1)) && + N0.getOperand(0).getOpcode() == ISD::ZERO_EXTEND && + N0.hasOneUse()) { + if (N0.getOpcode() == ISD::SHL) { + // If the original shl may be shifting out bits, do not perform this + // transformation. + unsigned ShAmt = cast<ConstantSDNode>(N0.getOperand(1))->getZExtValue(); + unsigned KnownZeroBits = N0.getOperand(0).getValueType().getSizeInBits() - + N0.getOperand(0).getOperand(0).getValueType().getSizeInBits(); + if (ShAmt > KnownZeroBits) + return SDValue(); + } + DebugLoc dl = N->getDebugLoc(); + return DAG.getNode(N0.getOpcode(), dl, VT, + DAG.getNode(ISD::ZERO_EXTEND, dl, VT, N0.getOperand(0)), + DAG.getNode(ISD::ZERO_EXTEND, dl, + N0.getOperand(1).getValueType(), + N0.getOperand(1))); + } + + return SDValue(); +} + +SDValue DAGCombiner::visitANY_EXTEND(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + + // fold (aext c1) -> c1 + if (isa<ConstantSDNode>(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<ConstantSDNode>(N0.getOperand(1))->getAPIntValue(); + 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))) + if (ISD::isNON_EXTLoad(N0.getNode()) && + ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || + TLI.isLoadExtLegal(ISD::EXTLOAD, N0.getValueType()))) { + bool DoXform = true; + SmallVector<SDNode*, 4> SetCCs; + if (!N0.hasOneUse()) + DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::ANY_EXTEND, SetCCs, TLI); + if (DoXform) { + LoadSDNode *LN0 = cast<LoadSDNode>(N0); + SDValue ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, VT, N->getDebugLoc(), + LN0->getChain(), + LN0->getBasePtr(), LN0->getSrcValue(), + LN0->getSrcValueOffset(), + 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<SDValue, 4> 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<LoadSDNode>(N0); + EVT MemVT = LN0->getMemoryVT(); + SDValue ExtLoad = DAG.getExtLoad(LN0->getExtensionType(), VT, + N->getDebugLoc(), + LN0->getChain(), LN0->getBasePtr(), + LN0->getSrcValue(), + LN0->getSrcValueOffset(), 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<CondCodeSDNode>(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<CondCodeSDNode>(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<CondCodeSDNode>(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<ConstantSDNode>(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<VTSDNode>(N->getOperand(1))->getVT(); + if (LegalOperations && !TLI.isLoadExtLegal(ISD::SEXTLOAD, ExtVT)) + return SDValue(); + } else if (Opc == ISD::SRL) { + // Annother special-case: SRL is basically zero-extending a narrower + // value. + ExtType = ISD::ZEXTLOAD; + N0 = SDValue(N, 0); + ConstantSDNode *N01 = dyn_cast<ConstantSDNode>(N0.getOperand(1)); + if (!N01) return SDValue(); + ExtVT = EVT::getIntegerVT(*DAG.getContext(), + VT.getSizeInBits() - N01->getZExtValue()); + } + + unsigned EVTBits = ExtVT.getSizeInBits(); + unsigned ShAmt = 0; + if (N0.getOpcode() == ISD::SRL && N0.hasOneUse() && ExtVT.isRound()) { + if (ConstantSDNode *N01 = dyn_cast<ConstantSDNode>(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(); + } + } + } + + // 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 (isa<LoadSDNode>(N0) && N0.hasOneUse() && ExtVT.isRound() && + cast<LoadSDNode>(N0)->getMemoryVT().getSizeInBits() >= EVTBits && + // Do not change the width of a volatile load. + !cast<LoadSDNode>(N0)->isVolatile()) { + LoadSDNode *LN0 = cast<LoadSDNode>(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 = (ExtType == ISD::NON_EXTLOAD) + ? DAG.getLoad(VT, N0.getDebugLoc(), LN0->getChain(), NewPtr, + LN0->getSrcValue(), LN0->getSrcValueOffset() + PtrOff, + LN0->isVolatile(), LN0->isNonTemporal(), NewAlign) + : DAG.getExtLoad(ExtType, VT, N0.getDebugLoc(), LN0->getChain(), NewPtr, + LN0->getSrcValue(), LN0->getSrcValueOffset() + 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); + + // Return the new loaded value. + return Load; + } + + return SDValue(); +} + +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<VTSDNode>(N1)->getVT(); + unsigned VTBits = VT.getScalarType().getSizeInBits(); + unsigned EVTBits = EVT.getScalarType().getSizeInBits(); + + // fold (sext_in_reg c1) -> c1 + if (isa<ConstantSDNode>(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<VTSDNode>(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<ConstantSDNode>(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<LoadSDNode>(N0)->getMemoryVT() && + ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || + TLI.isLoadExtLegal(ISD::SEXTLOAD, EVT))) { + LoadSDNode *LN0 = cast<LoadSDNode>(N0); + SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N->getDebugLoc(), + LN0->getChain(), + LN0->getBasePtr(), LN0->getSrcValue(), + LN0->getSrcValueOffset(), 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<LoadSDNode>(N0)->getMemoryVT() && + ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || + TLI.isLoadExtLegal(ISD::SEXTLOAD, EVT))) { + LoadSDNode *LN0 = cast<LoadSDNode>(N0); + SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N->getDebugLoc(), + LN0->getChain(), + LN0->getBasePtr(), LN0->getSrcValue(), + LN0->getSrcValueOffset(), 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<ConstantSDNode>(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 + 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<LoadSDNode>(getBuildPairElt(N, 0)); + LoadSDNode *LD2 = dyn_cast<LoadSDNode>(getBuildPairElt(N, 1)); + if (!LD1 || !LD2 || !ISD::isNON_EXTLoad(LD1) || !LD1->hasOneUse()) + 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->getSrcValue(), + LD1->getSrcValueOffset(), false, false, Align); + } + + return SDValue(); +} + +SDValue DAGCombiner::visitBIT_CONVERT(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 ConstantFoldBIT_CONVERTofBUILD_VECTOR(N0.getNode(), DestEltVT); + } + + // If the input is a constant, let getNode fold it. + if (isa<ConstantSDNode>(N0) || isa<ConstantFPSDNode>(N0)) { + SDValue Res = DAG.getNode(ISD::BIT_CONVERT, 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::BIT_CONVERT) + return DAG.getNode(ISD::BIT_CONVERT, 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<LoadSDNode>(N0)->isVolatile() && + (!LegalOperations || TLI.isOperationLegal(ISD::LOAD, VT))) { + LoadSDNode *LN0 = cast<LoadSDNode>(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->getSrcValue(), LN0->getSrcValueOffset(), + LN0->isVolatile(), LN0->isNonTemporal(), + OrigAlign); + AddToWorkList(N); + CombineTo(N0.getNode(), + DAG.getNode(ISD::BIT_CONVERT, 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::BIT_CONVERT, 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<ConstantFPSDNode>(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::BIT_CONVERT, 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::BIT_CONVERT, 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); +} + +/// ConstantFoldBIT_CONVERTofBUILD_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:: +ConstantFoldBIT_CONVERTofBUILD_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::BIT_CONVERT, BV->getDebugLoc(), + DstEltVT, BV->getOperand(0))); + + SmallVector<SDValue, 8> 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::BIT_CONVERT, 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 = ConstantFoldBIT_CONVERTofBUILD_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 = ConstantFoldBIT_CONVERTofBUILD_VECTOR(BV, TmpVT).getNode(); + + // Next, convert to FP elements of the same size. + return ConstantFoldBIT_CONVERTofBUILD_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<SDValue, 8> 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 |= APInt(cast<ConstantSDNode>(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<SDValue, 8> 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 = APInt(cast<ConstantSDNode>(BV->getOperand(i))-> + getAPIntValue()).zextOrTrunc(SrcBitSize); + + for (unsigned j = 0; j != NumOutputsPerInput; ++j) { + APInt ThisVal = APInt(OpVal).trunc(DstBitSize); + Ops.push_back(DAG.getConstant(ThisVal, DstEltVT)); + if (isS2V && i == 0 && j == 0 && APInt(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<ConstantFPSDNode>(N0); + ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(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<ConstantFPSDNode>(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<ConstantFPSDNode>(N0); + ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(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<ConstantFPSDNode>(N0); + ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(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<ConstantFPSDNode>(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<ConstantFPSDNode>(N0); + ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(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<ConstantFPSDNode>(N0); + ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(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<ConstantFPSDNode>(N0); + ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(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<ConstantSDNode>(N0); + EVT VT = N->getValueType(0); + EVT OpVT = N0.getValueType(); + + // fold (sint_to_fp c1) -> c1fp + if (N0C && OpVT != MVT::ppcf128) + 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<ConstantSDNode>(N0); + EVT VT = N->getValueType(0); + EVT OpVT = N0.getValueType(); + + // fold (uint_to_fp c1) -> c1fp + if (N0C && OpVT != MVT::ppcf128) + 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<ConstantFPSDNode>(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<ConstantFPSDNode>(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<ConstantFPSDNode>(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<VTSDNode>(N->getOperand(1))->getVT(); + ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(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<ConstantFPSDNode>(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<LoadSDNode>(N0)->isVolatile()) || + TLI.isLoadExtLegal(ISD::EXTLOAD, N0.getValueType()))) { + LoadSDNode *LN0 = cast<LoadSDNode>(N0); + SDValue ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, VT, N->getDebugLoc(), + LN0->getChain(), + LN0->getBasePtr(), LN0->getSrcValue(), + LN0->getSrcValueOffset(), + 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::BIT_CONVERT && + !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::BIT_CONVERT, N->getDebugLoc(), + VT, Int); + } + } + + return SDValue(); +} + +SDValue DAGCombiner::visitFABS(SDNode *N) { + SDValue N0 = N->getOperand(0); + ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(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::BIT_CONVERT && 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::BIT_CONVERT, 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); + } + + SDNode *Trunc = 0; + if (N1.getOpcode() == ISD::TRUNCATE && N1.hasOneUse()) { + // Look past truncate. + Trunc = N1.getNode(); + N1 = N1.getOperand(0); + } + + if (N1.hasOneUse() && N1.getOpcode() == ISD::SRL) { + // 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<ConstantSDNode>(AndOp1)->getAPIntValue(); + + if (AndConst.isPowerOf2() && + cast<ConstantSDNode>(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! + } + } + } + } + + // 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<ConstantSDNode>(Op0)) + if (RHSCI->getAPIntValue() == 1 && Op0.hasOneUse() && + Op0.getOpcode() == ISD::XOR) { + TheXor = Op0.getNode(); + Equal = true; + } + + SDValue NodeToReplace = Trunc ? SDValue(Trunc, 0) : N1; + + EVT SetCCVT = NodeToReplace.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(NodeToReplace, SetCC, &DeadNodes); + removeFromWorkList(NodeToReplace.getNode()); + DAG.DeleteNode(NodeToReplace.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<CondCodeSDNode>(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<LoadSDNode>(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<StoreSDNode>(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<ConstantSDNode>(Offset) && + cast<ConstantSDNode>(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<FrameIndexSDNode>(BasePtr) || isa<RegisterSDNode>(BasePtr)) + return false; + + // Check #2. + if (!isLoad) { + SDValue Val = cast<StoreSDNode>(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<LoadSDNode>(Use)->getBasePtr() == Ptr) || + (Use->getOpcode() == ISD::STORE && + cast<StoreSDNode>(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<LoadSDNode>(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<StoreSDNode>(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<ConstantSDNode>(Offset) && + cast<ConstantSDNode>(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<FrameIndexSDNode>(BasePtr) || isa<RegisterSDNode>(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<LoadSDNode>(UseUse)->getBasePtr().getNode() == Use) || + (UseUse->getOpcode() == ISD::STORE && + cast<StoreSDNode>(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<LoadSDNode>(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 (LD->getExtensionType() == ISD::NON_EXTLOAD && + !LD->isVolatile()) { + if (ISD::isNON_TRUNCStore(Chain.getNode())) { + StoreSDNode *PrevST = cast<StoreSDNode>(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(), LD->getValueType(0), + N->getDebugLoc(), + Chain, Ptr, LD->getSrcValue(), + LD->getSrcValueOffset(), 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->getSrcValue(), LD->getSrcValueOffset(), + LD->isVolatile(), LD->isNonTemporal(), + LD->getAlignment()); + } else { + ReplLoad = DAG.getExtLoad(LD->getExtensionType(), LD->getValueType(0), + LD->getDebugLoc(), + BetterChain, Ptr, LD->getSrcValue(), + LD->getSrcValueOffset(), + 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<unsigned, unsigned> +CheckForMaskedLoad(SDValue V, SDValue Ptr, SDValue Chain) { + std::pair<unsigned, unsigned> Result(0, 0); + + // Check for the structure we're looking for. + if (V->getOpcode() != ISD::AND || + !isa<ConstantSDNode>(V->getOperand(1)) || + !ISD::isNormalLoad(V->getOperand(0).getNode())) + return Result; + + // Check the chain and pointer. + LoadSDNode *LD = cast<LoadSDNode>(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<ConstantSDNode>(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<unsigned, unsigned> &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())); + + // 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->getSrcValue(), St->getSrcValueOffset()+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<StoreSDNode>(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<unsigned, unsigned> 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<LoadSDNode>(N0); + if (LD->getBasePtr() != Ptr) + 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<ConstantSDNode>(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->getSrcValue(), LD->getSrcValueOffset(), + 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->getSrcValue(), ST->getSrcValueOffset(), + 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(); +} + +SDValue DAGCombiner::visitSTORE(SDNode *N) { + StoreSDNode *ST = cast<StoreSDNode>(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::BIT_CONVERT && !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->getSrcValue(), + ST->getSrcValueOffset(), ST->isVolatile(), + ST->isNonTemporal(), OrigAlign); + } + + // Turn 'store float 1.0, Ptr' -> 'store int 0x12345678, Ptr' + if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(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->getSrcValue(), + ST->getSrcValueOffset(), 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->getSrcValue(), + ST->getSrcValueOffset(), 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); + + int SVOffset = ST->getSrcValueOffset(); + unsigned Alignment = ST->getAlignment(); + bool isVolatile = ST->isVolatile(); + bool isNonTemporal = ST->isNonTemporal(); + + SDValue St0 = DAG.getStore(Chain, ST->getDebugLoc(), Lo, + Ptr, ST->getSrcValue(), + ST->getSrcValueOffset(), + isVolatile, isNonTemporal, + ST->getAlignment()); + Ptr = DAG.getNode(ISD::ADD, N->getDebugLoc(), Ptr.getValueType(), Ptr, + DAG.getConstant(4, Ptr.getValueType())); + SVOffset += 4; + Alignment = MinAlign(Alignment, 4U); + SDValue St1 = DAG.getStore(Chain, ST->getDebugLoc(), Hi, + Ptr, ST->getSrcValue(), + SVOffset, 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->getSrcValue(), + ST->getSrcValueOffset(), ST->getMemoryVT(), + ST->isVolatile(), ST->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 ReplStore; + + // Replace the chain to avoid dependency. + if (ST->isTruncatingStore()) { + ReplStore = DAG.getTruncStore(BetterChain, N->getDebugLoc(), Value, Ptr, + ST->getSrcValue(),ST->getSrcValueOffset(), + ST->getMemoryVT(), ST->isVolatile(), + ST->isNonTemporal(), ST->getAlignment()); + } else { + ReplStore = DAG.getStore(BetterChain, N->getDebugLoc(), Value, Ptr, + ST->getSrcValue(), ST->getSrcValueOffset(), + 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->getSrcValue(), + ST->getSrcValueOffset(), 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<LoadSDNode>(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->getSrcValue(), + ST->getSrcValueOffset(), 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; + + // 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<ConstantSDNode>(EltNo)) { + unsigned Elt = cast<ConstantSDNode>(EltNo)->getZExtValue(); + SmallVector<SDValue, 8> Ops(InVec.getNode()->op_begin(), + InVec.getNode()->op_end()); + if (Elt < Ops.size()) + Ops[Elt] = InVal; + return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), + InVec.getValueType(), &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 (!LegalOperations && InVec.getOpcode() == ISD::UNDEF && + isa<ConstantSDNode>(EltNo)) { + EVT VT = InVec.getValueType(); + EVT EltVT = VT.getVectorElementType(); + unsigned NElts = VT.getVectorNumElements(); + SmallVector<SDValue, 8> Ops(NElts, DAG.getUNDEF(EltVT)); + + unsigned Elt = cast<ConstantSDNode>(EltNo)->getZExtValue(); + if (Elt < Ops.size()) + Ops[Elt] = InVal; + return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), + InVec.getValueType(), &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<ConstantSDNode>(EltNo)) { + unsigned Elt = cast<ConstantSDNode>(EltNo)->getZExtValue(); + bool NewLoad = false; + bool BCNumEltsChanged = false; + EVT VT = InVec.getValueType(); + EVT ExtVT = VT.getVectorElementType(); + EVT LVT = ExtVT; + + if (InVec.getOpcode() == ISD::BIT_CONVERT) { + 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<LoadSDNode>(InVec); + } else if (InVec.getOpcode() == ISD::SCALAR_TO_VECTOR && + InVec.getOperand(0).getValueType() == ExtVT && + ISD::isNormalLoad(InVec.getOperand(0).getNode())) { + LN0 = cast<LoadSDNode>(InVec.getOperand(0)); + } else if ((SVN = dyn_cast<ShuffleVectorSDNode>(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 > NumElems) ? -1 : SVN->getMaskElt(Elt); + InVec = (Idx < (int)NumElems) ? InVec.getOperand(0) : InVec.getOperand(1); + + if (InVec.getOpcode() == ISD::BIT_CONVERT) + InVec = InVec.getOperand(0); + if (ISD::isNormalLoad(InVec.getNode())) { + LN0 = cast<LoadSDNode>(InVec); + Elt = (Idx < (int)NumElems) ? Idx : Idx - (int)NumElems; + } + } + + if (!LN0 || !LN0->hasOneUse() || LN0->isVolatile()) + return SDValue(); + + 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(); + if (Elt) { + unsigned 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->getSrcValue(), LN0->getSrcValueOffset(), + 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<ConstantSDNode>(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<int, 8> 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<ConstantSDNode>(ExtVal)->getZExtValue(); + if (ExtIndex > VT.getVectorNumElements()) + return SDValue(); + + Mask.push_back(ExtIndex); + continue; + } + + // Otherwise, use InIdx + VecSize + unsigned Idx = cast<ConstantSDNode>(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 a build_vector with + // all scalar elements the same. + if (cast<ShuffleVectorSDNode>(N)->isSplat()) { + 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::BIT_CONVERT) { + SDValue ConvInput = V->getOperand(0); + if (ConvInput.getValueType().isVector() && + ConvInput.getValueType().getVectorNumElements() == NumElts) + V = ConvInput.getNode(); + } + + if (V->getOpcode() == ISD::BUILD_VECTOR) { + unsigned NumElems = V->getNumOperands(); + unsigned BaseIdx = cast<ShuffleVectorSDNode>(N)->getSplatIndex(); + if (NumElems > BaseIdx) { + SDValue Base; + bool AllSame = true; + for (unsigned i = 0; i != NumElems; ++i) { + if (V->getOperand(i).getOpcode() != ISD::UNDEF) { + Base = V->getOperand(i); + break; + } + } + // Splat of <u, u, u, u>, return <u, u, u, u> + if (!Base.getNode()) + return N0; + for (unsigned i = 0; i != NumElems; ++i) { + if (V->getOperand(i) != Base) { + AllSame = false; + break; + } + } + // Splat of <x, x, x, x>, return <x, x, x, x> + 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::BIT_CONVERT) + RHS = RHS.getOperand(0); + if (RHS.getOpcode() == ISD::BUILD_VECTOR) { + SmallVector<int, 8> Indices; + unsigned NumElts = RHS.getNumOperands(); + for (unsigned i = 0; i != NumElts; ++i) { + SDValue Elt = RHS.getOperand(i); + if (!isa<ConstantSDNode>(Elt)) + return SDValue(); + else if (cast<ConstantSDNode>(Elt)->isAllOnesValue()) + Indices.push_back(i); + else if (cast<ConstantSDNode>(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<SDValue,8> 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::BIT_CONVERT, dl, RVT, LHS); + SDValue Shuf = DAG.getVectorShuffle(RVT, dl, LHS, Zero, &Indices[0]); + return DAG.getNode(ISD::BIT_CONVERT, 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(); + + EVT VT = N->getValueType(0); + assert(VT.isVector() && "SimplifyVBinOp only works on vectors!"); + + EVT EltType = VT.getVectorElementType(); + 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<SDValue, 8> 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<ConstantSDNode>(RHSOp.getNode())->isNullValue()) || + (RHSOp.getOpcode() == ISD::ConstantFP && + cast<ConstantFPSDNode>(RHSOp.getNode())->getValueAPF().isZero())) + break; + } + + // If the vector element type is not legal, the BUILD_VECTOR operands + // are promoted and implicitly truncated. Make that explicit here. + if (LHSOp.getValueType() != EltType) + LHSOp = DAG.getNode(ISD::TRUNCATE, LHS.getDebugLoc(), EltType, LHSOp); + if (RHSOp.getValueType() != EltType) + RHSOp = DAG.getNode(ISD::TRUNCATE, RHS.getDebugLoc(), EltType, RHSOp); + + SDValue FoldOp = DAG.getNode(N->getOpcode(), LHS.getDebugLoc(), EltType, + 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()) { + EVT VT = LHS.getValueType(); + return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), VT, + &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<CondCodeSDNode>(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) { + + // 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()){ + // 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 && + // Do not let this transformation reduce the number of volatile loads. + !cast<LoadSDNode>(LHS)->isVolatile() && + !cast<LoadSDNode>(RHS)->isVolatile() && + // Token chains must be identical. + LHS.getOperand(0) == RHS.getOperand(0)) { + LoadSDNode *LLD = cast<LoadSDNode>(LHS); + LoadSDNode *RLD = cast<LoadSDNode>(RHS); + + // If this is an EXTLOAD, the VT's must match. + if (LLD->getMemoryVT() == RLD->getMemoryVT()) { + // 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. + unsigned LLDAddrSpace = 0, RLDAddrSpace = 0; + if (const Value *LLDVal = LLD->getMemOperand()->getValue()) { + if (const PointerType *PT = dyn_cast<PointerType>(LLDVal->getType())) + LLDAddrSpace = PT->getAddressSpace(); + } + if (const Value *RLDVal = RLD->getMemOperand()->getValue()) { + if (const PointerType *PT = dyn_cast<PointerType>(RLDVal->getType())) + RLDAddrSpace = PT->getAddressSpace(); + } + SDValue Addr; + if (LLDAddrSpace == 0 && RLDAddrSpace == 0) { + if (TheSelect->getOpcode() == ISD::SELECT) { + // Check that the condition doesn't reach either load. If so, folding + // this will induce a cycle into the DAG. + if ((!LLD->hasAnyUseOfValue(1) || + !LLD->isPredecessorOf(TheSelect->getOperand(0).getNode())) && + (!RLD->hasAnyUseOfValue(1) || + !RLD->isPredecessorOf(TheSelect->getOperand(0).getNode()))) { + Addr = DAG.getNode(ISD::SELECT, TheSelect->getDebugLoc(), + LLD->getBasePtr().getValueType(), + TheSelect->getOperand(0), LLD->getBasePtr(), + RLD->getBasePtr()); + } + } else { + // Check that the condition doesn't reach either load. If so, folding + // this will induce a cycle into the DAG. + if ((!LLD->hasAnyUseOfValue(1) || + (!LLD->isPredecessorOf(TheSelect->getOperand(0).getNode()) && + !LLD->isPredecessorOf(TheSelect->getOperand(1).getNode()))) && + (!RLD->hasAnyUseOfValue(1) || + (!RLD->isPredecessorOf(TheSelect->getOperand(0).getNode()) && + !RLD->isPredecessorOf(TheSelect->getOperand(1).getNode())))) { + Addr = DAG.getNode(ISD::SELECT_CC, TheSelect->getDebugLoc(), + LLD->getBasePtr().getValueType(), + TheSelect->getOperand(0), + TheSelect->getOperand(1), + LLD->getBasePtr(), RLD->getBasePtr(), + TheSelect->getOperand(4)); + } + } + } + + if (Addr.getNode()) { + SDValue Load; + if (LLD->getExtensionType() == ISD::NON_EXTLOAD) { + Load = DAG.getLoad(TheSelect->getValueType(0), + TheSelect->getDebugLoc(), + LLD->getChain(), + Addr, 0, 0, + LLD->isVolatile(), + LLD->isNonTemporal(), + LLD->getAlignment()); + } else { + Load = DAG.getExtLoad(LLD->getExtensionType(), + TheSelect->getValueType(0), + TheSelect->getDebugLoc(), + LLD->getChain(), Addr, 0, 0, + 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<ConstantSDNode>(N1.getNode()); + ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2.getNode()); + ConstantSDNode *N3C = dyn_cast<ConstantSDNode>(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<ConstantSDNode>(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<ConstantFPSDNode>(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<ConstantFPSDNode>(N2)) + if (ConstantFPSDNode *FV = dyn_cast<ConstantFPSDNode>(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<ConstantFP*>(FV->getConstantFPValue()), + const_cast<ConstantFP*>(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<ConstantPoolSDNode>(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, + PseudoSourceValue::getConstantPool(), 0, 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()); + 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())); + 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 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())); + } + + // 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())); + } + // 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())); + } + // 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())); + 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<ConstantSDNode>(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<ConstantSDNode>(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())); + 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: +/// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html> +SDValue DAGCombiner::BuildSDIV(SDNode *N) { + std::vector<SDNode*> Built; + SDValue S = TLI.BuildSDIV(N, DAG, &Built); + + for (std::vector<SDNode*>::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: +/// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html> +SDValue DAGCombiner::BuildUDIV(SDNode *N) { + std::vector<SDNode*> Built; + SDValue S = TLI.BuildUDIV(N, DAG, &Built); + + for (std::vector<SDNode*>::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<ConstantSDNode>(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<GlobalAddressSDNode>(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<ConstantPoolSDNode>(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<FrameIndexSDNode>(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, + SDValue Ptr2, int64_t Size2, + const Value *SrcValue2, int SrcValueOffset2, + unsigned SrcValueAlign2) 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); + + // 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(SrcValue1, Overlap1, SrcValue2, Overlap2); + 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 { + if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) { + Ptr = LD->getBasePtr(); + Size = LD->getMemoryVT().getSizeInBits() >> 3; + SrcValue = LD->getSrcValue(); + SrcValueOffset = LD->getSrcValueOffset(); + SrcValueAlign = LD->getOriginalAlignment(); + return true; + } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) { + Ptr = ST->getBasePtr(); + Size = ST->getMemoryVT().getSizeInBits() >> 3; + SrcValue = ST->getSrcValue(); + SrcValueOffset = ST->getSrcValueOffset(); + SrcValueAlign = ST->getOriginalAlignment(); + } 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<SDValue, 8> &Aliases) { + SmallVector<SDValue, 8> Chains; // List of chains to visit. + SmallPtrSet<SDNode *, 16> Visited; // Visited node set. + + // Get alias information for node. + SDValue Ptr; + int64_t Size; + const Value *SrcValue; + int SrcValueOffset; + unsigned SrcValueAlign; + bool IsLoad = FindAliasInfo(N, Ptr, Size, SrcValue, SrcValueOffset, + SrcValueAlign); + + // 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; + bool IsOpLoad = FindAliasInfo(Chain.getNode(), OpPtr, OpSize, + OpSrcValue, OpSrcValueOffset, + OpSrcValueAlign); + + // If chain is alias then stop here. + if (!(IsLoad && IsOpLoad) && + isAlias(Ptr, Size, SrcValue, SrcValueOffset, SrcValueAlign, + OpPtr, OpSize, OpSrcValue, OpSrcValueOffset, + OpSrcValueAlign)) { + 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<SDValue, 8> 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); +} |