//===-- SystemZISelDAGToDAG.cpp - A dag to dag inst selector for SystemZ --===// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // //===----------------------------------------------------------------------===// // // This file defines an instruction selector for the SystemZ target. // //===----------------------------------------------------------------------===// #include "SystemZTargetMachine.h" #include "SystemZISelLowering.h" #include "llvm/Analysis/AliasAnalysis.h" #include "llvm/CodeGen/SelectionDAGISel.h" #include "llvm/Support/Debug.h" #include "llvm/Support/KnownBits.h" #include "llvm/Support/raw_ostream.h" using namespace llvm; #define DEBUG_TYPE "systemz-isel" #define PASS_NAME "SystemZ DAG->DAG Pattern Instruction Selection" namespace { // Used to build addressing modes. struct SystemZAddressingMode { // The shape of the address. enum AddrForm { // base+displacement FormBD, // base+displacement+index for load and store operands FormBDXNormal, // base+displacement+index for load address operands FormBDXLA, // base+displacement+index+ADJDYNALLOC FormBDXDynAlloc }; AddrForm Form; // The type of displacement. The enum names here correspond directly // to the definitions in SystemZOperand.td. We could split them into // flags -- single/pair, 128-bit, etc. -- but it hardly seems worth it. enum DispRange { Disp12Only, Disp12Pair, Disp20Only, Disp20Only128, Disp20Pair }; DispRange DR; // The parts of the address. The address is equivalent to: // // Base + Disp + Index + (IncludesDynAlloc ? ADJDYNALLOC : 0) SDValue Base; int64_t Disp; SDValue Index; bool IncludesDynAlloc; SystemZAddressingMode(AddrForm form, DispRange dr) : Form(form), DR(dr), Disp(0), IncludesDynAlloc(false) {} // True if the address can have an index register. bool hasIndexField() { return Form != FormBD; } // True if the address can (and must) include ADJDYNALLOC. bool isDynAlloc() { return Form == FormBDXDynAlloc; } void dump(const llvm::SelectionDAG *DAG) { errs() << "SystemZAddressingMode " << this << '\n'; errs() << " Base "; if (Base.getNode()) Base.getNode()->dump(DAG); else errs() << "null\n"; if (hasIndexField()) { errs() << " Index "; if (Index.getNode()) Index.getNode()->dump(DAG); else errs() << "null\n"; } errs() << " Disp " << Disp; if (IncludesDynAlloc) errs() << " + ADJDYNALLOC"; errs() << '\n'; } }; // Return a mask with Count low bits set. static uint64_t allOnes(unsigned int Count) { assert(Count <= 64); if (Count > 63) return UINT64_MAX; return (uint64_t(1) << Count) - 1; } // Represents operands 2 to 5 of the ROTATE AND ... SELECTED BITS operation // given by Opcode. The operands are: Input (R2), Start (I3), End (I4) and // Rotate (I5). The combined operand value is effectively: // // (or (rotl Input, Rotate), ~Mask) // // for RNSBG and: // // (and (rotl Input, Rotate), Mask) // // otherwise. The output value has BitSize bits, although Input may be // narrower (in which case the upper bits are don't care), or wider (in which // case the result will be truncated as part of the operation). struct RxSBGOperands { RxSBGOperands(unsigned Op, SDValue N) : Opcode(Op), BitSize(N.getValueSizeInBits()), Mask(allOnes(BitSize)), Input(N), Start(64 - BitSize), End(63), Rotate(0) {} unsigned Opcode; unsigned BitSize; uint64_t Mask; SDValue Input; unsigned Start; unsigned End; unsigned Rotate; }; class SystemZDAGToDAGISel : public SelectionDAGISel { const SystemZSubtarget *Subtarget; // Used by SystemZOperands.td to create integer constants. inline SDValue getImm(const SDNode *Node, uint64_t Imm) const { return CurDAG->getTargetConstant(Imm, SDLoc(Node), Node->getValueType(0)); } const SystemZTargetMachine &getTargetMachine() const { return static_cast(TM); } const SystemZInstrInfo *getInstrInfo() const { return Subtarget->getInstrInfo(); } // Try to fold more of the base or index of AM into AM, where IsBase // selects between the base and index. bool expandAddress(SystemZAddressingMode &AM, bool IsBase) const; // Try to describe N in AM, returning true on success. bool selectAddress(SDValue N, SystemZAddressingMode &AM) const; // Extract individual target operands from matched address AM. void getAddressOperands(const SystemZAddressingMode &AM, EVT VT, SDValue &Base, SDValue &Disp) const; void getAddressOperands(const SystemZAddressingMode &AM, EVT VT, SDValue &Base, SDValue &Disp, SDValue &Index) const; // Try to match Addr as a FormBD address with displacement type DR. // Return true on success, storing the base and displacement in // Base and Disp respectively. bool selectBDAddr(SystemZAddressingMode::DispRange DR, SDValue Addr, SDValue &Base, SDValue &Disp) const; // Try to match Addr as a FormBDX address with displacement type DR. // Return true on success and if the result had no index. Store the // base and displacement in Base and Disp respectively. bool selectMVIAddr(SystemZAddressingMode::DispRange DR, SDValue Addr, SDValue &Base, SDValue &Disp) const; // Try to match Addr as a FormBDX* address of form Form with // displacement type DR. Return true on success, storing the base, // displacement and index in Base, Disp and Index respectively. bool selectBDXAddr(SystemZAddressingMode::AddrForm Form, SystemZAddressingMode::DispRange DR, SDValue Addr, SDValue &Base, SDValue &Disp, SDValue &Index) const; // PC-relative address matching routines used by SystemZOperands.td. bool selectPCRelAddress(SDValue Addr, SDValue &Target) const { if (SystemZISD::isPCREL(Addr.getOpcode())) { Target = Addr.getOperand(0); return true; } return false; } // BD matching routines used by SystemZOperands.td. bool selectBDAddr12Only(SDValue Addr, SDValue &Base, SDValue &Disp) const { return selectBDAddr(SystemZAddressingMode::Disp12Only, Addr, Base, Disp); } bool selectBDAddr12Pair(SDValue Addr, SDValue &Base, SDValue &Disp) const { return selectBDAddr(SystemZAddressingMode::Disp12Pair, Addr, Base, Disp); } bool selectBDAddr20Only(SDValue Addr, SDValue &Base, SDValue &Disp) const { return selectBDAddr(SystemZAddressingMode::Disp20Only, Addr, Base, Disp); } bool selectBDAddr20Pair(SDValue Addr, SDValue &Base, SDValue &Disp) const { return selectBDAddr(SystemZAddressingMode::Disp20Pair, Addr, Base, Disp); } // MVI matching routines used by SystemZOperands.td. bool selectMVIAddr12Pair(SDValue Addr, SDValue &Base, SDValue &Disp) const { return selectMVIAddr(SystemZAddressingMode::Disp12Pair, Addr, Base, Disp); } bool selectMVIAddr20Pair(SDValue Addr, SDValue &Base, SDValue &Disp) const { return selectMVIAddr(SystemZAddressingMode::Disp20Pair, Addr, Base, Disp); } // BDX matching routines used by SystemZOperands.td. bool selectBDXAddr12Only(SDValue Addr, SDValue &Base, SDValue &Disp, SDValue &Index) const { return selectBDXAddr(SystemZAddressingMode::FormBDXNormal, SystemZAddressingMode::Disp12Only, Addr, Base, Disp, Index); } bool selectBDXAddr12Pair(SDValue Addr, SDValue &Base, SDValue &Disp, SDValue &Index) const { return selectBDXAddr(SystemZAddressingMode::FormBDXNormal, SystemZAddressingMode::Disp12Pair, Addr, Base, Disp, Index); } bool selectDynAlloc12Only(SDValue Addr, SDValue &Base, SDValue &Disp, SDValue &Index) const { return selectBDXAddr(SystemZAddressingMode::FormBDXDynAlloc, SystemZAddressingMode::Disp12Only, Addr, Base, Disp, Index); } bool selectBDXAddr20Only(SDValue Addr, SDValue &Base, SDValue &Disp, SDValue &Index) const { return selectBDXAddr(SystemZAddressingMode::FormBDXNormal, SystemZAddressingMode::Disp20Only, Addr, Base, Disp, Index); } bool selectBDXAddr20Only128(SDValue Addr, SDValue &Base, SDValue &Disp, SDValue &Index) const { return selectBDXAddr(SystemZAddressingMode::FormBDXNormal, SystemZAddressingMode::Disp20Only128, Addr, Base, Disp, Index); } bool selectBDXAddr20Pair(SDValue Addr, SDValue &Base, SDValue &Disp, SDValue &Index) const { return selectBDXAddr(SystemZAddressingMode::FormBDXNormal, SystemZAddressingMode::Disp20Pair, Addr, Base, Disp, Index); } bool selectLAAddr12Pair(SDValue Addr, SDValue &Base, SDValue &Disp, SDValue &Index) const { return selectBDXAddr(SystemZAddressingMode::FormBDXLA, SystemZAddressingMode::Disp12Pair, Addr, Base, Disp, Index); } bool selectLAAddr20Pair(SDValue Addr, SDValue &Base, SDValue &Disp, SDValue &Index) const { return selectBDXAddr(SystemZAddressingMode::FormBDXLA, SystemZAddressingMode::Disp20Pair, Addr, Base, Disp, Index); } // Try to match Addr as an address with a base, 12-bit displacement // and index, where the index is element Elem of a vector. // Return true on success, storing the base, displacement and vector // in Base, Disp and Index respectively. bool selectBDVAddr12Only(SDValue Addr, SDValue Elem, SDValue &Base, SDValue &Disp, SDValue &Index) const; // Check whether (or Op (and X InsertMask)) is effectively an insertion // of X into bits InsertMask of some Y != Op. Return true if so and // set Op to that Y. bool detectOrAndInsertion(SDValue &Op, uint64_t InsertMask) const; // Try to update RxSBG so that only the bits of RxSBG.Input in Mask are used. // Return true on success. bool refineRxSBGMask(RxSBGOperands &RxSBG, uint64_t Mask) const; // Try to fold some of RxSBG.Input into other fields of RxSBG. // Return true on success. bool expandRxSBG(RxSBGOperands &RxSBG) const; // Return an undefined value of type VT. SDValue getUNDEF(const SDLoc &DL, EVT VT) const; // Convert N to VT, if it isn't already. SDValue convertTo(const SDLoc &DL, EVT VT, SDValue N) const; // Try to implement AND or shift node N using RISBG with the zero flag set. // Return the selected node on success, otherwise return null. bool tryRISBGZero(SDNode *N); // Try to use RISBG or Opcode to implement OR or XOR node N. // Return the selected node on success, otherwise return null. bool tryRxSBG(SDNode *N, unsigned Opcode); // If Op0 is null, then Node is a constant that can be loaded using: // // (Opcode UpperVal LowerVal) // // If Op0 is nonnull, then Node can be implemented using: // // (Opcode (Opcode Op0 UpperVal) LowerVal) void splitLargeImmediate(unsigned Opcode, SDNode *Node, SDValue Op0, uint64_t UpperVal, uint64_t LowerVal); void loadVectorConstant(const SystemZVectorConstantInfo &VCI, SDNode *Node); SDNode *loadPoolVectorConstant(APInt Val, EVT VT, SDLoc DL); // Try to use gather instruction Opcode to implement vector insertion N. bool tryGather(SDNode *N, unsigned Opcode); // Try to use scatter instruction Opcode to implement store Store. bool tryScatter(StoreSDNode *Store, unsigned Opcode); // Change a chain of {load; op; store} of the same value into a simple op // through memory of that value, if the uses of the modified value and its // address are suitable. bool tryFoldLoadStoreIntoMemOperand(SDNode *Node); // Return true if Load and Store are loads and stores of the same size // and are guaranteed not to overlap. Such operations can be implemented // using block (SS-format) instructions. // // Partial overlap would lead to incorrect code, since the block operations // are logically bytewise, even though they have a fast path for the // non-overlapping case. We also need to avoid full overlap (i.e. two // addresses that might be equal at run time) because although that case // would be handled correctly, it might be implemented by millicode. bool canUseBlockOperation(StoreSDNode *Store, LoadSDNode *Load) const; // N is a (store (load Y), X) pattern. Return true if it can use an MVC // from Y to X. bool storeLoadCanUseMVC(SDNode *N) const; // N is a (store (op (load A[0]), (load A[1])), X) pattern. Return true // if A[1 - I] == X and if N can use a block operation like NC from A[I] // to X. bool storeLoadCanUseBlockBinary(SDNode *N, unsigned I) const; // Return true if N (a load or a store) fullfills the alignment // requirements for a PC-relative access. bool storeLoadIsAligned(SDNode *N) const; // Try to expand a boolean SELECT_CCMASK using an IPM sequence. SDValue expandSelectBoolean(SDNode *Node); public: static char ID; SystemZDAGToDAGISel() = delete; SystemZDAGToDAGISel(SystemZTargetMachine &TM, CodeGenOptLevel OptLevel) : SelectionDAGISel(ID, TM, OptLevel) {} bool runOnMachineFunction(MachineFunction &MF) override { const Function &F = MF.getFunction(); if (F.getFnAttribute("fentry-call").getValueAsString() != "true") { if (F.hasFnAttribute("mnop-mcount")) report_fatal_error("mnop-mcount only supported with fentry-call"); if (F.hasFnAttribute("mrecord-mcount")) report_fatal_error("mrecord-mcount only supported with fentry-call"); } Subtarget = &MF.getSubtarget(); return SelectionDAGISel::runOnMachineFunction(MF); } // Override SelectionDAGISel. void Select(SDNode *Node) override; bool SelectInlineAsmMemoryOperand(const SDValue &Op, InlineAsm::ConstraintCode ConstraintID, std::vector &OutOps) override; bool IsProfitableToFold(SDValue N, SDNode *U, SDNode *Root) const override; void PreprocessISelDAG() override; // Include the pieces autogenerated from the target description. #include "SystemZGenDAGISel.inc" }; } // end anonymous namespace char SystemZDAGToDAGISel::ID = 0; INITIALIZE_PASS(SystemZDAGToDAGISel, DEBUG_TYPE, PASS_NAME, false, false) FunctionPass *llvm::createSystemZISelDag(SystemZTargetMachine &TM, CodeGenOptLevel OptLevel) { return new SystemZDAGToDAGISel(TM, OptLevel); } // Return true if Val should be selected as a displacement for an address // with range DR. Here we're interested in the range of both the instruction // described by DR and of any pairing instruction. static bool selectDisp(SystemZAddressingMode::DispRange DR, int64_t Val) { switch (DR) { case SystemZAddressingMode::Disp12Only: return isUInt<12>(Val); case SystemZAddressingMode::Disp12Pair: case SystemZAddressingMode::Disp20Only: case SystemZAddressingMode::Disp20Pair: return isInt<20>(Val); case SystemZAddressingMode::Disp20Only128: return isInt<20>(Val) && isInt<20>(Val + 8); } llvm_unreachable("Unhandled displacement range"); } // Change the base or index in AM to Value, where IsBase selects // between the base and index. static void changeComponent(SystemZAddressingMode &AM, bool IsBase, SDValue Value) { if (IsBase) AM.Base = Value; else AM.Index = Value; } // The base or index of AM is equivalent to Value + ADJDYNALLOC, // where IsBase selects between the base and index. Try to fold the // ADJDYNALLOC into AM. static bool expandAdjDynAlloc(SystemZAddressingMode &AM, bool IsBase, SDValue Value) { if (AM.isDynAlloc() && !AM.IncludesDynAlloc) { changeComponent(AM, IsBase, Value); AM.IncludesDynAlloc = true; return true; } return false; } // The base of AM is equivalent to Base + Index. Try to use Index as // the index register. static bool expandIndex(SystemZAddressingMode &AM, SDValue Base, SDValue Index) { if (AM.hasIndexField() && !AM.Index.getNode()) { AM.Base = Base; AM.Index = Index; return true; } return false; } // The base or index of AM is equivalent to Op0 + Op1, where IsBase selects // between the base and index. Try to fold Op1 into AM's displacement. static bool expandDisp(SystemZAddressingMode &AM, bool IsBase, SDValue Op0, uint64_t Op1) { // First try adjusting the displacement. int64_t TestDisp = AM.Disp + Op1; if (selectDisp(AM.DR, TestDisp)) { changeComponent(AM, IsBase, Op0); AM.Disp = TestDisp; return true; } // We could consider forcing the displacement into a register and // using it as an index, but it would need to be carefully tuned. return false; } bool SystemZDAGToDAGISel::expandAddress(SystemZAddressingMode &AM, bool IsBase) const { SDValue N = IsBase ? AM.Base : AM.Index; unsigned Opcode = N.getOpcode(); // Look through no-op truncations. if (Opcode == ISD::TRUNCATE && N.getOperand(0).getValueSizeInBits() <= 64) { N = N.getOperand(0); Opcode = N.getOpcode(); } if (Opcode == ISD::ADD || CurDAG->isBaseWithConstantOffset(N)) { SDValue Op0 = N.getOperand(0); SDValue Op1 = N.getOperand(1); unsigned Op0Code = Op0->getOpcode(); unsigned Op1Code = Op1->getOpcode(); if (Op0Code == SystemZISD::ADJDYNALLOC) return expandAdjDynAlloc(AM, IsBase, Op1); if (Op1Code == SystemZISD::ADJDYNALLOC) return expandAdjDynAlloc(AM, IsBase, Op0); if (Op0Code == ISD::Constant) return expandDisp(AM, IsBase, Op1, cast(Op0)->getSExtValue()); if (Op1Code == ISD::Constant) return expandDisp(AM, IsBase, Op0, cast(Op1)->getSExtValue()); if (IsBase && expandIndex(AM, Op0, Op1)) return true; } if (Opcode == SystemZISD::PCREL_OFFSET) { SDValue Full = N.getOperand(0); SDValue Base = N.getOperand(1); SDValue Anchor = Base.getOperand(0); uint64_t Offset = (cast(Full)->getOffset() - cast(Anchor)->getOffset()); return expandDisp(AM, IsBase, Base, Offset); } return false; } // Return true if an instruction with displacement range DR should be // used for displacement value Val. selectDisp(DR, Val) must already hold. static bool isValidDisp(SystemZAddressingMode::DispRange DR, int64_t Val) { assert(selectDisp(DR, Val) && "Invalid displacement"); switch (DR) { case SystemZAddressingMode::Disp12Only: case SystemZAddressingMode::Disp20Only: case SystemZAddressingMode::Disp20Only128: return true; case SystemZAddressingMode::Disp12Pair: // Use the other instruction if the displacement is too large. return isUInt<12>(Val); case SystemZAddressingMode::Disp20Pair: // Use the other instruction if the displacement is small enough. return !isUInt<12>(Val); } llvm_unreachable("Unhandled displacement range"); } // Return true if Base + Disp + Index should be performed by LA(Y). static bool shouldUseLA(SDNode *Base, int64_t Disp, SDNode *Index) { // Don't use LA(Y) for constants. if (!Base) return false; // Always use LA(Y) for frame addresses, since we know that the destination // register is almost always (perhaps always) going to be different from // the frame register. if (Base->getOpcode() == ISD::FrameIndex) return true; if (Disp) { // Always use LA(Y) if there is a base, displacement and index. if (Index) return true; // Always use LA if the displacement is small enough. It should always // be no worse than AGHI (and better if it avoids a move). if (isUInt<12>(Disp)) return true; // For similar reasons, always use LAY if the constant is too big for AGHI. // LAY should be no worse than AGFI. if (!isInt<16>(Disp)) return true; } else { // Don't use LA for plain registers. if (!Index) return false; // Don't use LA for plain addition if the index operand is only used // once. It should be a natural two-operand addition in that case. if (Index->hasOneUse()) return false; // Prefer addition if the second operation is sign-extended, in the // hope of using AGF. unsigned IndexOpcode = Index->getOpcode(); if (IndexOpcode == ISD::SIGN_EXTEND || IndexOpcode == ISD::SIGN_EXTEND_INREG) return false; } // Don't use LA for two-operand addition if either operand is only // used once. The addition instructions are better in that case. if (Base->hasOneUse()) return false; return true; } // Return true if Addr is suitable for AM, updating AM if so. bool SystemZDAGToDAGISel::selectAddress(SDValue Addr, SystemZAddressingMode &AM) const { // Start out assuming that the address will need to be loaded separately, // then try to extend it as much as we can. AM.Base = Addr; // First try treating the address as a constant. if (Addr.getOpcode() == ISD::Constant && expandDisp(AM, true, SDValue(), cast(Addr)->getSExtValue())) ; // Also see if it's a bare ADJDYNALLOC. else if (Addr.getOpcode() == SystemZISD::ADJDYNALLOC && expandAdjDynAlloc(AM, true, SDValue())) ; else // Otherwise try expanding each component. while (expandAddress(AM, true) || (AM.Index.getNode() && expandAddress(AM, false))) continue; // Reject cases where it isn't profitable to use LA(Y). if (AM.Form == SystemZAddressingMode::FormBDXLA && !shouldUseLA(AM.Base.getNode(), AM.Disp, AM.Index.getNode())) return false; // Reject cases where the other instruction in a pair should be used. if (!isValidDisp(AM.DR, AM.Disp)) return false; // Make sure that ADJDYNALLOC is included where necessary. if (AM.isDynAlloc() && !AM.IncludesDynAlloc) return false; LLVM_DEBUG(AM.dump(CurDAG)); return true; } // Insert a node into the DAG at least before Pos. This will reposition // the node as needed, and will assign it a node ID that is <= Pos's ID. // Note that this does *not* preserve the uniqueness of node IDs! // The selection DAG must no longer depend on their uniqueness when this // function is used. static void insertDAGNode(SelectionDAG *DAG, SDNode *Pos, SDValue N) { if (N->getNodeId() == -1 || (SelectionDAGISel::getUninvalidatedNodeId(N.getNode()) > SelectionDAGISel::getUninvalidatedNodeId(Pos))) { DAG->RepositionNode(Pos->getIterator(), N.getNode()); // Mark Node as invalid for pruning as after this it may be a successor to a // selected node but otherwise be in the same position of Pos. // Conservatively mark it with the same -abs(Id) to assure node id // invariant is preserved. N->setNodeId(Pos->getNodeId()); SelectionDAGISel::InvalidateNodeId(N.getNode()); } } void SystemZDAGToDAGISel::getAddressOperands(const SystemZAddressingMode &AM, EVT VT, SDValue &Base, SDValue &Disp) const { Base = AM.Base; if (!Base.getNode()) // Register 0 means "no base". This is mostly useful for shifts. Base = CurDAG->getRegister(0, VT); else if (Base.getOpcode() == ISD::FrameIndex) { // Lower a FrameIndex to a TargetFrameIndex. int64_t FrameIndex = cast(Base)->getIndex(); Base = CurDAG->getTargetFrameIndex(FrameIndex, VT); } else if (Base.getValueType() != VT) { // Truncate values from i64 to i32, for shifts. assert(VT == MVT::i32 && Base.getValueType() == MVT::i64 && "Unexpected truncation"); SDLoc DL(Base); SDValue Trunc = CurDAG->getNode(ISD::TRUNCATE, DL, VT, Base); insertDAGNode(CurDAG, Base.getNode(), Trunc); Base = Trunc; } // Lower the displacement to a TargetConstant. Disp = CurDAG->getTargetConstant(AM.Disp, SDLoc(Base), VT); } void SystemZDAGToDAGISel::getAddressOperands(const SystemZAddressingMode &AM, EVT VT, SDValue &Base, SDValue &Disp, SDValue &Index) const { getAddressOperands(AM, VT, Base, Disp); Index = AM.Index; if (!Index.getNode()) // Register 0 means "no index". Index = CurDAG->getRegister(0, VT); } bool SystemZDAGToDAGISel::selectBDAddr(SystemZAddressingMode::DispRange DR, SDValue Addr, SDValue &Base, SDValue &Disp) const { SystemZAddressingMode AM(SystemZAddressingMode::FormBD, DR); if (!selectAddress(Addr, AM)) return false; getAddressOperands(AM, Addr.getValueType(), Base, Disp); return true; } bool SystemZDAGToDAGISel::selectMVIAddr(SystemZAddressingMode::DispRange DR, SDValue Addr, SDValue &Base, SDValue &Disp) const { SystemZAddressingMode AM(SystemZAddressingMode::FormBDXNormal, DR); if (!selectAddress(Addr, AM) || AM.Index.getNode()) return false; getAddressOperands(AM, Addr.getValueType(), Base, Disp); return true; } bool SystemZDAGToDAGISel::selectBDXAddr(SystemZAddressingMode::AddrForm Form, SystemZAddressingMode::DispRange DR, SDValue Addr, SDValue &Base, SDValue &Disp, SDValue &Index) const { SystemZAddressingMode AM(Form, DR); if (!selectAddress(Addr, AM)) return false; getAddressOperands(AM, Addr.getValueType(), Base, Disp, Index); return true; } bool SystemZDAGToDAGISel::selectBDVAddr12Only(SDValue Addr, SDValue Elem, SDValue &Base, SDValue &Disp, SDValue &Index) const { SDValue Regs[2]; if (selectBDXAddr12Only(Addr, Regs[0], Disp, Regs[1]) && Regs[0].getNode() && Regs[1].getNode()) { for (unsigned int I = 0; I < 2; ++I) { Base = Regs[I]; Index = Regs[1 - I]; // We can't tell here whether the index vector has the right type // for the access; the caller needs to do that instead. if (Index.getOpcode() == ISD::ZERO_EXTEND) Index = Index.getOperand(0); if (Index.getOpcode() == ISD::EXTRACT_VECTOR_ELT && Index.getOperand(1) == Elem) { Index = Index.getOperand(0); return true; } } } return false; } bool SystemZDAGToDAGISel::detectOrAndInsertion(SDValue &Op, uint64_t InsertMask) const { // We're only interested in cases where the insertion is into some operand // of Op, rather than into Op itself. The only useful case is an AND. if (Op.getOpcode() != ISD::AND) return false; // We need a constant mask. auto *MaskNode = dyn_cast(Op.getOperand(1).getNode()); if (!MaskNode) return false; // It's not an insertion of Op.getOperand(0) if the two masks overlap. uint64_t AndMask = MaskNode->getZExtValue(); if (InsertMask & AndMask) return false; // It's only an insertion if all bits are covered or are known to be zero. // The inner check covers all cases but is more expensive. uint64_t Used = allOnes(Op.getValueSizeInBits()); if (Used != (AndMask | InsertMask)) { KnownBits Known = CurDAG->computeKnownBits(Op.getOperand(0)); if (Used != (AndMask | InsertMask | Known.Zero.getZExtValue())) return false; } Op = Op.getOperand(0); return true; } bool SystemZDAGToDAGISel::refineRxSBGMask(RxSBGOperands &RxSBG, uint64_t Mask) const { const SystemZInstrInfo *TII = getInstrInfo(); if (RxSBG.Rotate != 0) Mask = (Mask << RxSBG.Rotate) | (Mask >> (64 - RxSBG.Rotate)); Mask &= RxSBG.Mask; if (TII->isRxSBGMask(Mask, RxSBG.BitSize, RxSBG.Start, RxSBG.End)) { RxSBG.Mask = Mask; return true; } return false; } // Return true if any bits of (RxSBG.Input & Mask) are significant. static bool maskMatters(RxSBGOperands &RxSBG, uint64_t Mask) { // Rotate the mask in the same way as RxSBG.Input is rotated. if (RxSBG.Rotate != 0) Mask = ((Mask << RxSBG.Rotate) | (Mask >> (64 - RxSBG.Rotate))); return (Mask & RxSBG.Mask) != 0; } bool SystemZDAGToDAGISel::expandRxSBG(RxSBGOperands &RxSBG) const { SDValue N = RxSBG.Input; unsigned Opcode = N.getOpcode(); switch (Opcode) { case ISD::TRUNCATE: { if (RxSBG.Opcode == SystemZ::RNSBG) return false; if (N.getOperand(0).getValueSizeInBits() > 64) return false; uint64_t BitSize = N.getValueSizeInBits(); uint64_t Mask = allOnes(BitSize); if (!refineRxSBGMask(RxSBG, Mask)) return false; RxSBG.Input = N.getOperand(0); return true; } case ISD::AND: { if (RxSBG.Opcode == SystemZ::RNSBG) return false; auto *MaskNode = dyn_cast(N.getOperand(1).getNode()); if (!MaskNode) return false; SDValue Input = N.getOperand(0); uint64_t Mask = MaskNode->getZExtValue(); if (!refineRxSBGMask(RxSBG, Mask)) { // If some bits of Input are already known zeros, those bits will have // been removed from the mask. See if adding them back in makes the // mask suitable. KnownBits Known = CurDAG->computeKnownBits(Input); Mask |= Known.Zero.getZExtValue(); if (!refineRxSBGMask(RxSBG, Mask)) return false; } RxSBG.Input = Input; return true; } case ISD::OR: { if (RxSBG.Opcode != SystemZ::RNSBG) return false; auto *MaskNode = dyn_cast(N.getOperand(1).getNode()); if (!MaskNode) return false; SDValue Input = N.getOperand(0); uint64_t Mask = ~MaskNode->getZExtValue(); if (!refineRxSBGMask(RxSBG, Mask)) { // If some bits of Input are already known ones, those bits will have // been removed from the mask. See if adding them back in makes the // mask suitable. KnownBits Known = CurDAG->computeKnownBits(Input); Mask &= ~Known.One.getZExtValue(); if (!refineRxSBGMask(RxSBG, Mask)) return false; } RxSBG.Input = Input; return true; } case ISD::ROTL: { // Any 64-bit rotate left can be merged into the RxSBG. if (RxSBG.BitSize != 64 || N.getValueType() != MVT::i64) return false; auto *CountNode = dyn_cast(N.getOperand(1).getNode()); if (!CountNode) return false; RxSBG.Rotate = (RxSBG.Rotate + CountNode->getZExtValue()) & 63; RxSBG.Input = N.getOperand(0); return true; } case ISD::ANY_EXTEND: // Bits above the extended operand are don't-care. RxSBG.Input = N.getOperand(0); return true; case ISD::ZERO_EXTEND: if (RxSBG.Opcode != SystemZ::RNSBG) { // Restrict the mask to the extended operand. unsigned InnerBitSize = N.getOperand(0).getValueSizeInBits(); if (!refineRxSBGMask(RxSBG, allOnes(InnerBitSize))) return false; RxSBG.Input = N.getOperand(0); return true; } [[fallthrough]]; case ISD::SIGN_EXTEND: { // Check that the extension bits are don't-care (i.e. are masked out // by the final mask). unsigned BitSize = N.getValueSizeInBits(); unsigned InnerBitSize = N.getOperand(0).getValueSizeInBits(); if (maskMatters(RxSBG, allOnes(BitSize) - allOnes(InnerBitSize))) { // In the case where only the sign bit is active, increase Rotate with // the extension width. if (RxSBG.Mask == 1 && RxSBG.Rotate == 1) RxSBG.Rotate += (BitSize - InnerBitSize); else return false; } RxSBG.Input = N.getOperand(0); return true; } case ISD::SHL: { auto *CountNode = dyn_cast(N.getOperand(1).getNode()); if (!CountNode) return false; uint64_t Count = CountNode->getZExtValue(); unsigned BitSize = N.getValueSizeInBits(); if (Count < 1 || Count >= BitSize) return false; if (RxSBG.Opcode == SystemZ::RNSBG) { // Treat (shl X, count) as (rotl X, size-count) as long as the bottom // count bits from RxSBG.Input are ignored. if (maskMatters(RxSBG, allOnes(Count))) return false; } else { // Treat (shl X, count) as (and (rotl X, count), ~0<(N.getOperand(1).getNode()); if (!CountNode) return false; uint64_t Count = CountNode->getZExtValue(); unsigned BitSize = N.getValueSizeInBits(); if (Count < 1 || Count >= BitSize) return false; if (RxSBG.Opcode == SystemZ::RNSBG || Opcode == ISD::SRA) { // Treat (srl|sra X, count) as (rotl X, size-count) as long as the top // count bits from RxSBG.Input are ignored. if (maskMatters(RxSBG, allOnes(Count) << (BitSize - Count))) return false; } else { // Treat (srl X, count), mask) as (and (rotl X, size-count), ~0>>count), // which is similar to SLL above. if (!refineRxSBGMask(RxSBG, allOnes(BitSize - Count))) return false; } RxSBG.Rotate = (RxSBG.Rotate - Count) & 63; RxSBG.Input = N.getOperand(0); return true; } default: return false; } } SDValue SystemZDAGToDAGISel::getUNDEF(const SDLoc &DL, EVT VT) const { SDNode *N = CurDAG->getMachineNode(TargetOpcode::IMPLICIT_DEF, DL, VT); return SDValue(N, 0); } SDValue SystemZDAGToDAGISel::convertTo(const SDLoc &DL, EVT VT, SDValue N) const { if (N.getValueType() == MVT::i32 && VT == MVT::i64) return CurDAG->getTargetInsertSubreg(SystemZ::subreg_l32, DL, VT, getUNDEF(DL, MVT::i64), N); if (N.getValueType() == MVT::i64 && VT == MVT::i32) return CurDAG->getTargetExtractSubreg(SystemZ::subreg_l32, DL, VT, N); assert(N.getValueType() == VT && "Unexpected value types"); return N; } bool SystemZDAGToDAGISel::tryRISBGZero(SDNode *N) { SDLoc DL(N); EVT VT = N->getValueType(0); if (!VT.isInteger() || VT.getSizeInBits() > 64) return false; RxSBGOperands RISBG(SystemZ::RISBG, SDValue(N, 0)); unsigned Count = 0; while (expandRxSBG(RISBG)) // The widening or narrowing is expected to be free. // Counting widening or narrowing as a saved operation will result in // preferring an R*SBG over a simple shift/logical instruction. if (RISBG.Input.getOpcode() != ISD::ANY_EXTEND && RISBG.Input.getOpcode() != ISD::TRUNCATE) Count += 1; if (Count == 0 || isa(RISBG.Input)) return false; // Prefer to use normal shift instructions over RISBG, since they can handle // all cases and are sometimes shorter. if (Count == 1 && N->getOpcode() != ISD::AND) return false; // Prefer register extensions like LLC over RISBG. Also prefer to start // out with normal ANDs if one instruction would be enough. We can convert // these ANDs into an RISBG later if a three-address instruction is useful. if (RISBG.Rotate == 0) { bool PreferAnd = false; // Prefer AND for any 32-bit and-immediate operation. if (VT == MVT::i32) PreferAnd = true; // As well as for any 64-bit operation that can be implemented via LLC(R), // LLH(R), LLGT(R), or one of the and-immediate instructions. else if (RISBG.Mask == 0xff || RISBG.Mask == 0xffff || RISBG.Mask == 0x7fffffff || SystemZ::isImmLF(~RISBG.Mask) || SystemZ::isImmHF(~RISBG.Mask)) PreferAnd = true; // And likewise for the LLZRGF instruction, which doesn't have a register // to register version. else if (auto *Load = dyn_cast(RISBG.Input)) { if (Load->getMemoryVT() == MVT::i32 && (Load->getExtensionType() == ISD::EXTLOAD || Load->getExtensionType() == ISD::ZEXTLOAD) && RISBG.Mask == 0xffffff00 && Subtarget->hasLoadAndZeroRightmostByte()) PreferAnd = true; } if (PreferAnd) { // Replace the current node with an AND. Note that the current node // might already be that same AND, in which case it is already CSE'd // with it, and we must not call ReplaceNode. SDValue In = convertTo(DL, VT, RISBG.Input); SDValue Mask = CurDAG->getConstant(RISBG.Mask, DL, VT); SDValue New = CurDAG->getNode(ISD::AND, DL, VT, In, Mask); if (N != New.getNode()) { insertDAGNode(CurDAG, N, Mask); insertDAGNode(CurDAG, N, New); ReplaceNode(N, New.getNode()); N = New.getNode(); } // Now, select the machine opcode to implement this operation. if (!N->isMachineOpcode()) SelectCode(N); return true; } } unsigned Opcode = SystemZ::RISBG; // Prefer RISBGN if available, since it does not clobber CC. if (Subtarget->hasMiscellaneousExtensions()) Opcode = SystemZ::RISBGN; EVT OpcodeVT = MVT::i64; if (VT == MVT::i32 && Subtarget->hasHighWord() && // We can only use the 32-bit instructions if all source bits are // in the low 32 bits without wrapping, both after rotation (because // of the smaller range for Start and End) and before rotation // (because the input value is truncated). RISBG.Start >= 32 && RISBG.End >= RISBG.Start && ((RISBG.Start + RISBG.Rotate) & 63) >= 32 && ((RISBG.End + RISBG.Rotate) & 63) >= ((RISBG.Start + RISBG.Rotate) & 63)) { Opcode = SystemZ::RISBMux; OpcodeVT = MVT::i32; RISBG.Start &= 31; RISBG.End &= 31; } SDValue Ops[5] = { getUNDEF(DL, OpcodeVT), convertTo(DL, OpcodeVT, RISBG.Input), CurDAG->getTargetConstant(RISBG.Start, DL, MVT::i32), CurDAG->getTargetConstant(RISBG.End | 128, DL, MVT::i32), CurDAG->getTargetConstant(RISBG.Rotate, DL, MVT::i32) }; SDValue New = convertTo( DL, VT, SDValue(CurDAG->getMachineNode(Opcode, DL, OpcodeVT, Ops), 0)); ReplaceNode(N, New.getNode()); return true; } bool SystemZDAGToDAGISel::tryRxSBG(SDNode *N, unsigned Opcode) { SDLoc DL(N); EVT VT = N->getValueType(0); if (!VT.isInteger() || VT.getSizeInBits() > 64) return false; // Try treating each operand of N as the second operand of the RxSBG // and see which goes deepest. RxSBGOperands RxSBG[] = { RxSBGOperands(Opcode, N->getOperand(0)), RxSBGOperands(Opcode, N->getOperand(1)) }; unsigned Count[] = { 0, 0 }; for (unsigned I = 0; I < 2; ++I) while (RxSBG[I].Input->hasOneUse() && expandRxSBG(RxSBG[I])) // In cases of multiple users it seems better to keep the simple // instruction as they are one cycle faster, and it also helps in cases // where both inputs share a common node. // The widening or narrowing is expected to be free. Counting widening // or narrowing as a saved operation will result in preferring an R*SBG // over a simple shift/logical instruction. if (RxSBG[I].Input.getOpcode() != ISD::ANY_EXTEND && RxSBG[I].Input.getOpcode() != ISD::TRUNCATE) Count[I] += 1; // Do nothing if neither operand is suitable. if (Count[0] == 0 && Count[1] == 0) return false; // Pick the deepest second operand. unsigned I = Count[0] > Count[1] ? 0 : 1; SDValue Op0 = N->getOperand(I ^ 1); // Prefer IC for character insertions from memory. if (Opcode == SystemZ::ROSBG && (RxSBG[I].Mask & 0xff) == 0) if (auto *Load = dyn_cast(Op0.getNode())) if (Load->getMemoryVT() == MVT::i8) return false; // See whether we can avoid an AND in the first operand by converting // ROSBG to RISBG. if (Opcode == SystemZ::ROSBG && detectOrAndInsertion(Op0, RxSBG[I].Mask)) { Opcode = SystemZ::RISBG; // Prefer RISBGN if available, since it does not clobber CC. if (Subtarget->hasMiscellaneousExtensions()) Opcode = SystemZ::RISBGN; } SDValue Ops[5] = { convertTo(DL, MVT::i64, Op0), convertTo(DL, MVT::i64, RxSBG[I].Input), CurDAG->getTargetConstant(RxSBG[I].Start, DL, MVT::i32), CurDAG->getTargetConstant(RxSBG[I].End, DL, MVT::i32), CurDAG->getTargetConstant(RxSBG[I].Rotate, DL, MVT::i32) }; SDValue New = convertTo( DL, VT, SDValue(CurDAG->getMachineNode(Opcode, DL, MVT::i64, Ops), 0)); ReplaceNode(N, New.getNode()); return true; } void SystemZDAGToDAGISel::splitLargeImmediate(unsigned Opcode, SDNode *Node, SDValue Op0, uint64_t UpperVal, uint64_t LowerVal) { EVT VT = Node->getValueType(0); SDLoc DL(Node); SDValue Upper = CurDAG->getConstant(UpperVal, DL, VT); if (Op0.getNode()) Upper = CurDAG->getNode(Opcode, DL, VT, Op0, Upper); { // When we haven't passed in Op0, Upper will be a constant. In order to // prevent folding back to the large immediate in `Or = getNode(...)` we run // SelectCode first and end up with an opaque machine node. This means that // we need to use a handle to keep track of Upper in case it gets CSE'd by // SelectCode. // // Note that in the case where Op0 is passed in we could just call // SelectCode(Upper) later, along with the SelectCode(Or), and avoid needing // the handle at all, but it's fine to do it here. // // TODO: This is a pretty hacky way to do this. Can we do something that // doesn't require a two paragraph explanation? HandleSDNode Handle(Upper); SelectCode(Upper.getNode()); Upper = Handle.getValue(); } SDValue Lower = CurDAG->getConstant(LowerVal, DL, VT); SDValue Or = CurDAG->getNode(Opcode, DL, VT, Upper, Lower); ReplaceNode(Node, Or.getNode()); SelectCode(Or.getNode()); } void SystemZDAGToDAGISel::loadVectorConstant( const SystemZVectorConstantInfo &VCI, SDNode *Node) { assert((VCI.Opcode == SystemZISD::BYTE_MASK || VCI.Opcode == SystemZISD::REPLICATE || VCI.Opcode == SystemZISD::ROTATE_MASK) && "Bad opcode!"); assert(VCI.VecVT.getSizeInBits() == 128 && "Expected a vector type"); EVT VT = Node->getValueType(0); SDLoc DL(Node); SmallVector Ops; for (unsigned OpVal : VCI.OpVals) Ops.push_back(CurDAG->getTargetConstant(OpVal, DL, MVT::i32)); SDValue Op = CurDAG->getNode(VCI.Opcode, DL, VCI.VecVT, Ops); if (VCI.VecVT == VT.getSimpleVT()) ReplaceNode(Node, Op.getNode()); else if (VT.getSizeInBits() == 128) { SDValue BitCast = CurDAG->getNode(ISD::BITCAST, DL, VT, Op); ReplaceNode(Node, BitCast.getNode()); SelectCode(BitCast.getNode()); } else { // float or double unsigned SubRegIdx = (VT.getSizeInBits() == 32 ? SystemZ::subreg_h32 : SystemZ::subreg_h64); ReplaceNode( Node, CurDAG->getTargetExtractSubreg(SubRegIdx, DL, VT, Op).getNode()); } SelectCode(Op.getNode()); } SDNode *SystemZDAGToDAGISel::loadPoolVectorConstant(APInt Val, EVT VT, SDLoc DL) { SDNode *ResNode; assert (VT.getSizeInBits() == 128); SDValue CP = CurDAG->getTargetConstantPool( ConstantInt::get(Type::getInt128Ty(*CurDAG->getContext()), Val), TLI->getPointerTy(CurDAG->getDataLayout())); EVT PtrVT = CP.getValueType(); SDValue Ops[] = { SDValue(CurDAG->getMachineNode(SystemZ::LARL, DL, PtrVT, CP), 0), CurDAG->getTargetConstant(0, DL, PtrVT), CurDAG->getRegister(0, PtrVT), CurDAG->getEntryNode() }; ResNode = CurDAG->getMachineNode(SystemZ::VL, DL, VT, MVT::Other, Ops); // Annotate ResNode with memory operand information so that MachineInstr // queries work properly. This e.g. gives the register allocation the // required information for rematerialization. MachineFunction& MF = CurDAG->getMachineFunction(); MachineMemOperand *MemOp = MF.getMachineMemOperand(MachinePointerInfo::getConstantPool(MF), MachineMemOperand::MOLoad, 16, Align(8)); CurDAG->setNodeMemRefs(cast(ResNode), {MemOp}); return ResNode; } bool SystemZDAGToDAGISel::tryGather(SDNode *N, unsigned Opcode) { SDValue ElemV = N->getOperand(2); auto *ElemN = dyn_cast(ElemV); if (!ElemN) return false; unsigned Elem = ElemN->getZExtValue(); EVT VT = N->getValueType(0); if (Elem >= VT.getVectorNumElements()) return false; auto *Load = dyn_cast(N->getOperand(1)); if (!Load || !Load->hasNUsesOfValue(1, 0)) return false; if (Load->getMemoryVT().getSizeInBits() != Load->getValueType(0).getSizeInBits()) return false; SDValue Base, Disp, Index; if (!selectBDVAddr12Only(Load->getBasePtr(), ElemV, Base, Disp, Index) || Index.getValueType() != VT.changeVectorElementTypeToInteger()) return false; SDLoc DL(Load); SDValue Ops[] = { N->getOperand(0), Base, Disp, Index, CurDAG->getTargetConstant(Elem, DL, MVT::i32), Load->getChain() }; SDNode *Res = CurDAG->getMachineNode(Opcode, DL, VT, MVT::Other, Ops); ReplaceUses(SDValue(Load, 1), SDValue(Res, 1)); ReplaceNode(N, Res); return true; } bool SystemZDAGToDAGISel::tryScatter(StoreSDNode *Store, unsigned Opcode) { SDValue Value = Store->getValue(); if (Value.getOpcode() != ISD::EXTRACT_VECTOR_ELT) return false; if (Store->getMemoryVT().getSizeInBits() != Value.getValueSizeInBits()) return false; SDValue ElemV = Value.getOperand(1); auto *ElemN = dyn_cast(ElemV); if (!ElemN) return false; SDValue Vec = Value.getOperand(0); EVT VT = Vec.getValueType(); unsigned Elem = ElemN->getZExtValue(); if (Elem >= VT.getVectorNumElements()) return false; SDValue Base, Disp, Index; if (!selectBDVAddr12Only(Store->getBasePtr(), ElemV, Base, Disp, Index) || Index.getValueType() != VT.changeVectorElementTypeToInteger()) return false; SDLoc DL(Store); SDValue Ops[] = { Vec, Base, Disp, Index, CurDAG->getTargetConstant(Elem, DL, MVT::i32), Store->getChain() }; ReplaceNode(Store, CurDAG->getMachineNode(Opcode, DL, MVT::Other, Ops)); return true; } // Check whether or not the chain ending in StoreNode is suitable for doing // the {load; op; store} to modify transformation. static bool isFusableLoadOpStorePattern(StoreSDNode *StoreNode, SDValue StoredVal, SelectionDAG *CurDAG, LoadSDNode *&LoadNode, SDValue &InputChain) { // Is the stored value result 0 of the operation? if (StoredVal.getResNo() != 0) return false; // Are there other uses of the loaded value than the operation? if (!StoredVal.getNode()->hasNUsesOfValue(1, 0)) return false; // Is the store non-extending and non-indexed? if (!ISD::isNormalStore(StoreNode) || StoreNode->isNonTemporal()) return false; SDValue Load = StoredVal->getOperand(0); // Is the stored value a non-extending and non-indexed load? if (!ISD::isNormalLoad(Load.getNode())) return false; // Return LoadNode by reference. LoadNode = cast(Load); // Is store the only read of the loaded value? if (!Load.hasOneUse()) return false; // Is the address of the store the same as the load? if (LoadNode->getBasePtr() != StoreNode->getBasePtr() || LoadNode->getOffset() != StoreNode->getOffset()) return false; // Check if the chain is produced by the load or is a TokenFactor with // the load output chain as an operand. Return InputChain by reference. SDValue Chain = StoreNode->getChain(); bool ChainCheck = false; if (Chain == Load.getValue(1)) { ChainCheck = true; InputChain = LoadNode->getChain(); } else if (Chain.getOpcode() == ISD::TokenFactor) { SmallVector ChainOps; SmallVector LoopWorklist; SmallPtrSet Visited; const unsigned int Max = 1024; for (unsigned i = 0, e = Chain.getNumOperands(); i != e; ++i) { SDValue Op = Chain.getOperand(i); if (Op == Load.getValue(1)) { ChainCheck = true; // Drop Load, but keep its chain. No cycle check necessary. ChainOps.push_back(Load.getOperand(0)); continue; } LoopWorklist.push_back(Op.getNode()); ChainOps.push_back(Op); } if (ChainCheck) { // Add the other operand of StoredVal to worklist. for (SDValue Op : StoredVal->ops()) if (Op.getNode() != LoadNode) LoopWorklist.push_back(Op.getNode()); // Check if Load is reachable from any of the nodes in the worklist. if (SDNode::hasPredecessorHelper(Load.getNode(), Visited, LoopWorklist, Max, true)) return false; // Make a new TokenFactor with all the other input chains except // for the load. InputChain = CurDAG->getNode(ISD::TokenFactor, SDLoc(Chain), MVT::Other, ChainOps); } } if (!ChainCheck) return false; return true; } // Change a chain of {load; op; store} of the same value into a simple op // through memory of that value, if the uses of the modified value and its // address are suitable. // // The tablegen pattern memory operand pattern is currently not able to match // the case where the CC on the original operation are used. // // See the equivalent routine in X86ISelDAGToDAG for further comments. bool SystemZDAGToDAGISel::tryFoldLoadStoreIntoMemOperand(SDNode *Node) { StoreSDNode *StoreNode = cast(Node); SDValue StoredVal = StoreNode->getOperand(1); unsigned Opc = StoredVal->getOpcode(); SDLoc DL(StoreNode); // Before we try to select anything, make sure this is memory operand size // and opcode we can handle. Note that this must match the code below that // actually lowers the opcodes. EVT MemVT = StoreNode->getMemoryVT(); unsigned NewOpc = 0; bool NegateOperand = false; switch (Opc) { default: return false; case SystemZISD::SSUBO: NegateOperand = true; [[fallthrough]]; case SystemZISD::SADDO: if (MemVT == MVT::i32) NewOpc = SystemZ::ASI; else if (MemVT == MVT::i64) NewOpc = SystemZ::AGSI; else return false; break; case SystemZISD::USUBO: NegateOperand = true; [[fallthrough]]; case SystemZISD::UADDO: if (MemVT == MVT::i32) NewOpc = SystemZ::ALSI; else if (MemVT == MVT::i64) NewOpc = SystemZ::ALGSI; else return false; break; } LoadSDNode *LoadNode = nullptr; SDValue InputChain; if (!isFusableLoadOpStorePattern(StoreNode, StoredVal, CurDAG, LoadNode, InputChain)) return false; SDValue Operand = StoredVal.getOperand(1); auto *OperandC = dyn_cast(Operand); if (!OperandC) return false; auto OperandV = OperandC->getAPIntValue(); if (NegateOperand) OperandV = -OperandV; if (OperandV.getSignificantBits() > 8) return false; Operand = CurDAG->getTargetConstant(OperandV, DL, MemVT); SDValue Base, Disp; if (!selectBDAddr20Only(StoreNode->getBasePtr(), Base, Disp)) return false; SDValue Ops[] = { Base, Disp, Operand, InputChain }; MachineSDNode *Result = CurDAG->getMachineNode(NewOpc, DL, MVT::i32, MVT::Other, Ops); CurDAG->setNodeMemRefs( Result, {StoreNode->getMemOperand(), LoadNode->getMemOperand()}); ReplaceUses(SDValue(StoreNode, 0), SDValue(Result, 1)); ReplaceUses(SDValue(StoredVal.getNode(), 1), SDValue(Result, 0)); CurDAG->RemoveDeadNode(Node); return true; } bool SystemZDAGToDAGISel::canUseBlockOperation(StoreSDNode *Store, LoadSDNode *Load) const { // Check that the two memory operands have the same size. if (Load->getMemoryVT() != Store->getMemoryVT()) return false; // Volatility stops an access from being decomposed. if (Load->isVolatile() || Store->isVolatile()) return false; // There's no chance of overlap if the load is invariant. if (Load->isInvariant() && Load->isDereferenceable()) return true; // Otherwise we need to check whether there's an alias. const Value *V1 = Load->getMemOperand()->getValue(); const Value *V2 = Store->getMemOperand()->getValue(); if (!V1 || !V2) return false; // Reject equality. uint64_t Size = Load->getMemoryVT().getStoreSize(); int64_t End1 = Load->getSrcValueOffset() + Size; int64_t End2 = Store->getSrcValueOffset() + Size; if (V1 == V2 && End1 == End2) return false; return AA->isNoAlias(MemoryLocation(V1, End1, Load->getAAInfo()), MemoryLocation(V2, End2, Store->getAAInfo())); } bool SystemZDAGToDAGISel::storeLoadCanUseMVC(SDNode *N) const { auto *Store = cast(N); auto *Load = cast(Store->getValue()); // Prefer not to use MVC if either address can use ... RELATIVE LONG // instructions. uint64_t Size = Load->getMemoryVT().getStoreSize(); if (Size > 1 && Size <= 8) { // Prefer LHRL, LRL and LGRL. if (SystemZISD::isPCREL(Load->getBasePtr().getOpcode())) return false; // Prefer STHRL, STRL and STGRL. if (SystemZISD::isPCREL(Store->getBasePtr().getOpcode())) return false; } return canUseBlockOperation(Store, Load); } bool SystemZDAGToDAGISel::storeLoadCanUseBlockBinary(SDNode *N, unsigned I) const { auto *StoreA = cast(N); auto *LoadA = cast(StoreA->getValue().getOperand(1 - I)); auto *LoadB = cast(StoreA->getValue().getOperand(I)); return !LoadA->isVolatile() && LoadA->getMemoryVT() == LoadB->getMemoryVT() && canUseBlockOperation(StoreA, LoadB); } bool SystemZDAGToDAGISel::storeLoadIsAligned(SDNode *N) const { auto *MemAccess = cast(N); TypeSize StoreSize = MemAccess->getMemoryVT().getStoreSize(); SDValue BasePtr = MemAccess->getBasePtr(); MachineMemOperand *MMO = MemAccess->getMemOperand(); assert(MMO && "Expected a memory operand."); // The memory access must have a proper alignment and no index register. if (MemAccess->getAlign().value() < StoreSize || !MemAccess->getOffset().isUndef()) return false; // The MMO must not have an unaligned offset. if (MMO->getOffset() % StoreSize != 0) return false; // An access to GOT or the Constant Pool is aligned. if (const PseudoSourceValue *PSV = MMO->getPseudoValue()) if ((PSV->isGOT() || PSV->isConstantPool())) return true; // Check the alignment of a Global Address. if (BasePtr.getNumOperands()) if (GlobalAddressSDNode *GA = dyn_cast(BasePtr.getOperand(0))) { // The immediate offset must be aligned. if (GA->getOffset() % StoreSize != 0) return false; // The alignment of the symbol itself must be at least the store size. const GlobalValue *GV = GA->getGlobal(); const DataLayout &DL = GV->getParent()->getDataLayout(); if (GV->getPointerAlignment(DL).value() < StoreSize) return false; } return true; } void SystemZDAGToDAGISel::Select(SDNode *Node) { // If we have a custom node, we already have selected! if (Node->isMachineOpcode()) { LLVM_DEBUG(errs() << "== "; Node->dump(CurDAG); errs() << "\n"); Node->setNodeId(-1); return; } unsigned Opcode = Node->getOpcode(); switch (Opcode) { case ISD::OR: if (Node->getOperand(1).getOpcode() != ISD::Constant) if (tryRxSBG(Node, SystemZ::ROSBG)) return; goto or_xor; case ISD::XOR: if (Node->getOperand(1).getOpcode() != ISD::Constant) if (tryRxSBG(Node, SystemZ::RXSBG)) return; // Fall through. or_xor: // If this is a 64-bit operation in which both 32-bit halves are nonzero, // split the operation into two. If both operands here happen to be // constant, leave this to common code to optimize. if (Node->getValueType(0) == MVT::i64 && Node->getOperand(0).getOpcode() != ISD::Constant) if (auto *Op1 = dyn_cast(Node->getOperand(1))) { uint64_t Val = Op1->getZExtValue(); // Don't split the operation if we can match one of the combined // logical operations provided by miscellaneous-extensions-3. if (Subtarget->hasMiscellaneousExtensions3()) { unsigned ChildOpcode = Node->getOperand(0).getOpcode(); // Check whether this expression matches NAND/NOR/NXOR. if (Val == (uint64_t)-1 && Opcode == ISD::XOR) if (ChildOpcode == ISD::AND || ChildOpcode == ISD::OR || ChildOpcode == ISD::XOR) break; // Check whether this expression matches OR-with-complement // (or matches an alternate pattern for NXOR). if (ChildOpcode == ISD::XOR) { auto Op0 = Node->getOperand(0); if (auto *Op0Op1 = dyn_cast(Op0->getOperand(1))) if (Op0Op1->getZExtValue() == (uint64_t)-1) break; } } // Don't split an XOR with -1 as LCGR/AGHI is more compact. if (Opcode == ISD::XOR && Op1->isAllOnes()) break; if (!SystemZ::isImmLF(Val) && !SystemZ::isImmHF(Val)) { splitLargeImmediate(Opcode, Node, Node->getOperand(0), Val - uint32_t(Val), uint32_t(Val)); return; } } break; case ISD::AND: if (Node->getOperand(1).getOpcode() != ISD::Constant) if (tryRxSBG(Node, SystemZ::RNSBG)) return; [[fallthrough]]; case ISD::ROTL: case ISD::SHL: case ISD::SRL: case ISD::ZERO_EXTEND: if (tryRISBGZero(Node)) return; break; case ISD::BSWAP: if (Node->getValueType(0) == MVT::i128) { SDLoc DL(Node); SDValue Src = Node->getOperand(0); Src = CurDAG->getNode(ISD::BITCAST, DL, MVT::v16i8, Src); uint64_t Bytes[2] = { 0x0706050403020100ULL, 0x0f0e0d0c0b0a0908ULL }; SDNode *Mask = loadPoolVectorConstant(APInt(128, Bytes), MVT::v16i8, DL); SDValue Ops[] = { Src, Src, SDValue(Mask, 0) }; SDValue Res = SDValue(CurDAG->getMachineNode(SystemZ::VPERM, DL, MVT::v16i8, Ops), 0); Res = CurDAG->getNode(ISD::BITCAST, DL, MVT::i128, Res); SDNode *ResNode = Res.getNode(); ReplaceNode(Node, ResNode); SelectCode(Src.getNode()); SelectCode(ResNode); return; } break; case ISD::Constant: // If this is a 64-bit constant that is out of the range of LLILF, // LLIHF and LGFI, split it into two 32-bit pieces. if (Node->getValueType(0) == MVT::i64) { uint64_t Val = Node->getAsZExtVal(); if (!SystemZ::isImmLF(Val) && !SystemZ::isImmHF(Val) && !isInt<32>(Val)) { splitLargeImmediate(ISD::OR, Node, SDValue(), Val - uint32_t(Val), uint32_t(Val)); return; } } if (Node->getValueType(0) == MVT::i128) { const APInt &Val = Node->getAsAPIntVal(); SystemZVectorConstantInfo VCI(Val); if (VCI.isVectorConstantLegal(*Subtarget)) { loadVectorConstant(VCI, Node); return; } // If we can't materialize the constant we need to use a literal pool. SDNode *ResNode = loadPoolVectorConstant(Val, MVT::i128, SDLoc(Node)); ReplaceNode(Node, ResNode); return; } break; case SystemZISD::SELECT_CCMASK: { SDValue Op0 = Node->getOperand(0); SDValue Op1 = Node->getOperand(1); // Prefer to put any load first, so that it can be matched as a // conditional load. Likewise for constants in range for LOCHI. if ((Op1.getOpcode() == ISD::LOAD && Op0.getOpcode() != ISD::LOAD) || (Subtarget->hasLoadStoreOnCond2() && Node->getValueType(0).isInteger() && Node->getValueType(0).getSizeInBits() <= 64 && Op1.getOpcode() == ISD::Constant && isInt<16>(cast(Op1)->getSExtValue()) && !(Op0.getOpcode() == ISD::Constant && isInt<16>(cast(Op0)->getSExtValue())))) { SDValue CCValid = Node->getOperand(2); SDValue CCMask = Node->getOperand(3); uint64_t ConstCCValid = CCValid.getNode()->getAsZExtVal(); uint64_t ConstCCMask = CCMask.getNode()->getAsZExtVal(); // Invert the condition. CCMask = CurDAG->getTargetConstant(ConstCCValid ^ ConstCCMask, SDLoc(Node), CCMask.getValueType()); SDValue Op4 = Node->getOperand(4); SDNode *UpdatedNode = CurDAG->UpdateNodeOperands(Node, Op1, Op0, CCValid, CCMask, Op4); if (UpdatedNode != Node) { // In case this node already exists then replace Node with it. ReplaceNode(Node, UpdatedNode); Node = UpdatedNode; } } break; } case ISD::INSERT_VECTOR_ELT: { EVT VT = Node->getValueType(0); unsigned ElemBitSize = VT.getScalarSizeInBits(); if (ElemBitSize == 32) { if (tryGather(Node, SystemZ::VGEF)) return; } else if (ElemBitSize == 64) { if (tryGather(Node, SystemZ::VGEG)) return; } break; } case ISD::BUILD_VECTOR: { auto *BVN = cast(Node); SystemZVectorConstantInfo VCI(BVN); if (VCI.isVectorConstantLegal(*Subtarget)) { loadVectorConstant(VCI, Node); return; } break; } case ISD::ConstantFP: { APFloat Imm = cast(Node)->getValueAPF(); if (Imm.isZero() || Imm.isNegZero()) break; SystemZVectorConstantInfo VCI(Imm); bool Success = VCI.isVectorConstantLegal(*Subtarget); (void)Success; assert(Success && "Expected legal FP immediate"); loadVectorConstant(VCI, Node); return; } case ISD::STORE: { if (tryFoldLoadStoreIntoMemOperand(Node)) return; auto *Store = cast(Node); unsigned ElemBitSize = Store->getValue().getValueSizeInBits(); if (ElemBitSize == 32) { if (tryScatter(Store, SystemZ::VSCEF)) return; } else if (ElemBitSize == 64) { if (tryScatter(Store, SystemZ::VSCEG)) return; } break; } } SelectCode(Node); } bool SystemZDAGToDAGISel::SelectInlineAsmMemoryOperand( const SDValue &Op, InlineAsm::ConstraintCode ConstraintID, std::vector &OutOps) { SystemZAddressingMode::AddrForm Form; SystemZAddressingMode::DispRange DispRange; SDValue Base, Disp, Index; switch(ConstraintID) { default: llvm_unreachable("Unexpected asm memory constraint"); case InlineAsm::ConstraintCode::i: case InlineAsm::ConstraintCode::Q: case InlineAsm::ConstraintCode::ZQ: // Accept an address with a short displacement, but no index. Form = SystemZAddressingMode::FormBD; DispRange = SystemZAddressingMode::Disp12Only; break; case InlineAsm::ConstraintCode::R: case InlineAsm::ConstraintCode::ZR: // Accept an address with a short displacement and an index. Form = SystemZAddressingMode::FormBDXNormal; DispRange = SystemZAddressingMode::Disp12Only; break; case InlineAsm::ConstraintCode::S: case InlineAsm::ConstraintCode::ZS: // Accept an address with a long displacement, but no index. Form = SystemZAddressingMode::FormBD; DispRange = SystemZAddressingMode::Disp20Only; break; case InlineAsm::ConstraintCode::T: case InlineAsm::ConstraintCode::m: case InlineAsm::ConstraintCode::o: case InlineAsm::ConstraintCode::p: case InlineAsm::ConstraintCode::ZT: // Accept an address with a long displacement and an index. // m works the same as T, as this is the most general case. // We don't really have any special handling of "offsettable" // memory addresses, so just treat o the same as m. Form = SystemZAddressingMode::FormBDXNormal; DispRange = SystemZAddressingMode::Disp20Only; break; } if (selectBDXAddr(Form, DispRange, Op, Base, Disp, Index)) { const TargetRegisterClass *TRC = Subtarget->getRegisterInfo()->getPointerRegClass(*MF); SDLoc DL(Base); SDValue RC = CurDAG->getTargetConstant(TRC->getID(), DL, MVT::i32); // Make sure that the base address doesn't go into %r0. // If it's a TargetFrameIndex or a fixed register, we shouldn't do anything. if (Base.getOpcode() != ISD::TargetFrameIndex && Base.getOpcode() != ISD::Register) { Base = SDValue(CurDAG->getMachineNode(TargetOpcode::COPY_TO_REGCLASS, DL, Base.getValueType(), Base, RC), 0); } // Make sure that the index register isn't assigned to %r0 either. if (Index.getOpcode() != ISD::Register) { Index = SDValue(CurDAG->getMachineNode(TargetOpcode::COPY_TO_REGCLASS, DL, Index.getValueType(), Index, RC), 0); } OutOps.push_back(Base); OutOps.push_back(Disp); OutOps.push_back(Index); return false; } return true; } // IsProfitableToFold - Returns true if is profitable to fold the specific // operand node N of U during instruction selection that starts at Root. bool SystemZDAGToDAGISel::IsProfitableToFold(SDValue N, SDNode *U, SDNode *Root) const { // We want to avoid folding a LOAD into an ICMP node if as a result // we would be forced to spill the condition code into a GPR. if (N.getOpcode() == ISD::LOAD && U->getOpcode() == SystemZISD::ICMP) { if (!N.hasOneUse() || !U->hasOneUse()) return false; // The user of the CC value will usually be a CopyToReg into the // physical CC register, which in turn is glued and chained to the // actual instruction that uses the CC value. Bail out if we have // anything else than that. SDNode *CCUser = *U->use_begin(); SDNode *CCRegUser = nullptr; if (CCUser->getOpcode() == ISD::CopyToReg || cast(CCUser->getOperand(1))->getReg() == SystemZ::CC) { for (auto *U : CCUser->uses()) { if (CCRegUser == nullptr) CCRegUser = U; else if (CCRegUser != U) return false; } } if (CCRegUser == nullptr) return false; // If the actual instruction is a branch, the only thing that remains to be // checked is whether the CCUser chain is a predecessor of the load. if (CCRegUser->isMachineOpcode() && CCRegUser->getMachineOpcode() == SystemZ::BRC) return !N->isPredecessorOf(CCUser->getOperand(0).getNode()); // Otherwise, the instruction may have multiple operands, and we need to // verify that none of them are a predecessor of the load. This is exactly // the same check that would be done by common code if the CC setter were // glued to the CC user, so simply invoke that check here. if (!IsLegalToFold(N, U, CCRegUser, OptLevel, false)) return false; } return true; } namespace { // Represents a sequence for extracting a 0/1 value from an IPM result: // (((X ^ XORValue) + AddValue) >> Bit) struct IPMConversion { IPMConversion(unsigned xorValue, int64_t addValue, unsigned bit) : XORValue(xorValue), AddValue(addValue), Bit(bit) {} int64_t XORValue; int64_t AddValue; unsigned Bit; }; } // end anonymous namespace // Return a sequence for getting a 1 from an IPM result when CC has a // value in CCMask and a 0 when CC has a value in CCValid & ~CCMask. // The handling of CC values outside CCValid doesn't matter. static IPMConversion getIPMConversion(unsigned CCValid, unsigned CCMask) { // Deal with cases where the result can be taken directly from a bit // of the IPM result. if (CCMask == (CCValid & (SystemZ::CCMASK_1 | SystemZ::CCMASK_3))) return IPMConversion(0, 0, SystemZ::IPM_CC); if (CCMask == (CCValid & (SystemZ::CCMASK_2 | SystemZ::CCMASK_3))) return IPMConversion(0, 0, SystemZ::IPM_CC + 1); // Deal with cases where we can add a value to force the sign bit // to contain the right value. Putting the bit in 31 means we can // use SRL rather than RISBG(L), and also makes it easier to get a // 0/-1 value, so it has priority over the other tests below. // // These sequences rely on the fact that the upper two bits of the // IPM result are zero. uint64_t TopBit = uint64_t(1) << 31; if (CCMask == (CCValid & SystemZ::CCMASK_0)) return IPMConversion(0, -(1 << SystemZ::IPM_CC), 31); if (CCMask == (CCValid & (SystemZ::CCMASK_0 | SystemZ::CCMASK_1))) return IPMConversion(0, -(2 << SystemZ::IPM_CC), 31); if (CCMask == (CCValid & (SystemZ::CCMASK_0 | SystemZ::CCMASK_1 | SystemZ::CCMASK_2))) return IPMConversion(0, -(3 << SystemZ::IPM_CC), 31); if (CCMask == (CCValid & SystemZ::CCMASK_3)) return IPMConversion(0, TopBit - (3 << SystemZ::IPM_CC), 31); if (CCMask == (CCValid & (SystemZ::CCMASK_1 | SystemZ::CCMASK_2 | SystemZ::CCMASK_3))) return IPMConversion(0, TopBit - (1 << SystemZ::IPM_CC), 31); // Next try inverting the value and testing a bit. 0/1 could be // handled this way too, but we dealt with that case above. if (CCMask == (CCValid & (SystemZ::CCMASK_0 | SystemZ::CCMASK_2))) return IPMConversion(-1, 0, SystemZ::IPM_CC); // Handle cases where adding a value forces a non-sign bit to contain // the right value. if (CCMask == (CCValid & (SystemZ::CCMASK_1 | SystemZ::CCMASK_2))) return IPMConversion(0, 1 << SystemZ::IPM_CC, SystemZ::IPM_CC + 1); if (CCMask == (CCValid & (SystemZ::CCMASK_0 | SystemZ::CCMASK_3))) return IPMConversion(0, -(1 << SystemZ::IPM_CC), SystemZ::IPM_CC + 1); // The remaining cases are 1, 2, 0/1/3 and 0/2/3. All these are // can be done by inverting the low CC bit and applying one of the // sign-based extractions above. if (CCMask == (CCValid & SystemZ::CCMASK_1)) return IPMConversion(1 << SystemZ::IPM_CC, -(1 << SystemZ::IPM_CC), 31); if (CCMask == (CCValid & SystemZ::CCMASK_2)) return IPMConversion(1 << SystemZ::IPM_CC, TopBit - (3 << SystemZ::IPM_CC), 31); if (CCMask == (CCValid & (SystemZ::CCMASK_0 | SystemZ::CCMASK_1 | SystemZ::CCMASK_3))) return IPMConversion(1 << SystemZ::IPM_CC, -(3 << SystemZ::IPM_CC), 31); if (CCMask == (CCValid & (SystemZ::CCMASK_0 | SystemZ::CCMASK_2 | SystemZ::CCMASK_3))) return IPMConversion(1 << SystemZ::IPM_CC, TopBit - (1 << SystemZ::IPM_CC), 31); llvm_unreachable("Unexpected CC combination"); } SDValue SystemZDAGToDAGISel::expandSelectBoolean(SDNode *Node) { auto *TrueOp = dyn_cast(Node->getOperand(0)); auto *FalseOp = dyn_cast(Node->getOperand(1)); if (!TrueOp || !FalseOp) return SDValue(); if (FalseOp->getZExtValue() != 0) return SDValue(); if (TrueOp->getSExtValue() != 1 && TrueOp->getSExtValue() != -1) return SDValue(); auto *CCValidOp = dyn_cast(Node->getOperand(2)); auto *CCMaskOp = dyn_cast(Node->getOperand(3)); if (!CCValidOp || !CCMaskOp) return SDValue(); int CCValid = CCValidOp->getZExtValue(); int CCMask = CCMaskOp->getZExtValue(); SDLoc DL(Node); SDValue CCReg = Node->getOperand(4); IPMConversion IPM = getIPMConversion(CCValid, CCMask); SDValue Result = CurDAG->getNode(SystemZISD::IPM, DL, MVT::i32, CCReg); if (IPM.XORValue) Result = CurDAG->getNode(ISD::XOR, DL, MVT::i32, Result, CurDAG->getConstant(IPM.XORValue, DL, MVT::i32)); if (IPM.AddValue) Result = CurDAG->getNode(ISD::ADD, DL, MVT::i32, Result, CurDAG->getConstant(IPM.AddValue, DL, MVT::i32)); EVT VT = Node->getValueType(0); if (VT == MVT::i32 && IPM.Bit == 31) { unsigned ShiftOp = TrueOp->getSExtValue() == 1 ? ISD::SRL : ISD::SRA; Result = CurDAG->getNode(ShiftOp, DL, MVT::i32, Result, CurDAG->getConstant(IPM.Bit, DL, MVT::i32)); } else { if (VT != MVT::i32) Result = CurDAG->getNode(ISD::ANY_EXTEND, DL, VT, Result); if (TrueOp->getSExtValue() == 1) { // The SHR/AND sequence should get optimized to an RISBG. Result = CurDAG->getNode(ISD::SRL, DL, VT, Result, CurDAG->getConstant(IPM.Bit, DL, MVT::i32)); Result = CurDAG->getNode(ISD::AND, DL, VT, Result, CurDAG->getConstant(1, DL, VT)); } else { // Sign-extend from IPM.Bit using a pair of shifts. int ShlAmt = VT.getSizeInBits() - 1 - IPM.Bit; int SraAmt = VT.getSizeInBits() - 1; Result = CurDAG->getNode(ISD::SHL, DL, VT, Result, CurDAG->getConstant(ShlAmt, DL, MVT::i32)); Result = CurDAG->getNode(ISD::SRA, DL, VT, Result, CurDAG->getConstant(SraAmt, DL, MVT::i32)); } } return Result; } void SystemZDAGToDAGISel::PreprocessISelDAG() { // If we have conditional immediate loads, we always prefer // using those over an IPM sequence. if (Subtarget->hasLoadStoreOnCond2()) return; bool MadeChange = false; for (SelectionDAG::allnodes_iterator I = CurDAG->allnodes_begin(), E = CurDAG->allnodes_end(); I != E;) { SDNode *N = &*I++; if (N->use_empty()) continue; SDValue Res; switch (N->getOpcode()) { default: break; case SystemZISD::SELECT_CCMASK: Res = expandSelectBoolean(N); break; } if (Res) { LLVM_DEBUG(dbgs() << "SystemZ DAG preprocessing replacing:\nOld: "); LLVM_DEBUG(N->dump(CurDAG)); LLVM_DEBUG(dbgs() << "\nNew: "); LLVM_DEBUG(Res.getNode()->dump(CurDAG)); LLVM_DEBUG(dbgs() << "\n"); CurDAG->ReplaceAllUsesOfValueWith(SDValue(N, 0), Res); MadeChange = true; } } if (MadeChange) CurDAG->RemoveDeadNodes(); }