//===- X86ISelDAGToDAG.cpp - A DAG pattern matching inst selector for X86 -===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file defines a DAG pattern matching instruction selector for X86, // converting from a legalized dag to a X86 dag. // //===----------------------------------------------------------------------===// #include "X86.h" #include "X86InstrBuilder.h" #include "X86MachineFunctionInfo.h" #include "X86RegisterInfo.h" #include "X86Subtarget.h" #include "X86TargetMachine.h" #include "llvm/ADT/Statistic.h" #include "llvm/CodeGen/MachineFrameInfo.h" #include "llvm/CodeGen/MachineFunction.h" #include "llvm/CodeGen/MachineInstrBuilder.h" #include "llvm/CodeGen/MachineRegisterInfo.h" #include "llvm/CodeGen/SelectionDAGISel.h" #include "llvm/IR/Instructions.h" #include "llvm/IR/Intrinsics.h" #include "llvm/IR/Type.h" #include "llvm/Support/Debug.h" #include "llvm/Support/ErrorHandling.h" #include "llvm/Support/MathExtras.h" #include "llvm/Support/raw_ostream.h" #include "llvm/Target/TargetMachine.h" #include "llvm/Target/TargetOptions.h" using namespace llvm; #define DEBUG_TYPE "x86-isel" STATISTIC(NumLoadMoved, "Number of loads moved below TokenFactor"); //===----------------------------------------------------------------------===// // Pattern Matcher Implementation //===----------------------------------------------------------------------===// namespace { /// X86ISelAddressMode - This corresponds to X86AddressMode, but uses /// SDValue's instead of register numbers for the leaves of the matched /// tree. struct X86ISelAddressMode { enum { RegBase, FrameIndexBase } BaseType; // This is really a union, discriminated by BaseType! SDValue Base_Reg; int Base_FrameIndex; unsigned Scale; SDValue IndexReg; int32_t Disp; SDValue Segment; const GlobalValue *GV; const Constant *CP; const BlockAddress *BlockAddr; const char *ES; int JT; unsigned Align; // CP alignment. unsigned char SymbolFlags; // X86II::MO_* X86ISelAddressMode() : BaseType(RegBase), Base_FrameIndex(0), Scale(1), IndexReg(), Disp(0), Segment(), GV(nullptr), CP(nullptr), BlockAddr(nullptr), ES(nullptr), JT(-1), Align(0), SymbolFlags(X86II::MO_NO_FLAG) { } bool hasSymbolicDisplacement() const { return GV != nullptr || CP != nullptr || ES != nullptr || JT != -1 || BlockAddr != nullptr; } bool hasBaseOrIndexReg() const { return BaseType == FrameIndexBase || IndexReg.getNode() != nullptr || Base_Reg.getNode() != nullptr; } /// isRIPRelative - Return true if this addressing mode is already RIP /// relative. bool isRIPRelative() const { if (BaseType != RegBase) return false; if (RegisterSDNode *RegNode = dyn_cast_or_null(Base_Reg.getNode())) return RegNode->getReg() == X86::RIP; return false; } void setBaseReg(SDValue Reg) { BaseType = RegBase; Base_Reg = Reg; } #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) void dump() { dbgs() << "X86ISelAddressMode " << this << '\n'; dbgs() << "Base_Reg "; if (Base_Reg.getNode()) Base_Reg.getNode()->dump(); else dbgs() << "nul"; dbgs() << " Base.FrameIndex " << Base_FrameIndex << '\n' << " Scale" << Scale << '\n' << "IndexReg "; if (IndexReg.getNode()) IndexReg.getNode()->dump(); else dbgs() << "nul"; dbgs() << " Disp " << Disp << '\n' << "GV "; if (GV) GV->dump(); else dbgs() << "nul"; dbgs() << " CP "; if (CP) CP->dump(); else dbgs() << "nul"; dbgs() << '\n' << "ES "; if (ES) dbgs() << ES; else dbgs() << "nul"; dbgs() << " JT" << JT << " Align" << Align << '\n'; } #endif }; } namespace { //===--------------------------------------------------------------------===// /// ISel - X86 specific code to select X86 machine instructions for /// SelectionDAG operations. /// class X86DAGToDAGISel final : public SelectionDAGISel { /// Subtarget - Keep a pointer to the X86Subtarget around so that we can /// make the right decision when generating code for different targets. const X86Subtarget *Subtarget; /// OptForSize - If true, selector should try to optimize for code size /// instead of performance. bool OptForSize; public: explicit X86DAGToDAGISel(X86TargetMachine &tm, CodeGenOpt::Level OptLevel) : SelectionDAGISel(tm, OptLevel), Subtarget(&tm.getSubtarget()), OptForSize(false) {} const char *getPassName() const override { return "X86 DAG->DAG Instruction Selection"; } bool runOnMachineFunction(MachineFunction &MF) override { // Reset the subtarget each time through. Subtarget = &TM.getSubtarget(); SelectionDAGISel::runOnMachineFunction(MF); return true; } void EmitFunctionEntryCode() override; bool IsProfitableToFold(SDValue N, SDNode *U, SDNode *Root) const override; void PreprocessISelDAG() override; inline bool immSext8(SDNode *N) const { return isInt<8>(cast(N)->getSExtValue()); } // i64immSExt32 predicate - True if the 64-bit immediate fits in a 32-bit // sign extended field. inline bool i64immSExt32(SDNode *N) const { uint64_t v = cast(N)->getZExtValue(); return (int64_t)v == (int32_t)v; } // Include the pieces autogenerated from the target description. #include "X86GenDAGISel.inc" private: SDNode *Select(SDNode *N) override; SDNode *SelectGather(SDNode *N, unsigned Opc); SDNode *SelectAtomic64(SDNode *Node, unsigned Opc); SDNode *SelectAtomicLoadArith(SDNode *Node, MVT NVT); bool FoldOffsetIntoAddress(uint64_t Offset, X86ISelAddressMode &AM); bool MatchLoadInAddress(LoadSDNode *N, X86ISelAddressMode &AM); bool MatchWrapper(SDValue N, X86ISelAddressMode &AM); bool MatchAddress(SDValue N, X86ISelAddressMode &AM); bool MatchAddressRecursively(SDValue N, X86ISelAddressMode &AM, unsigned Depth); bool MatchAddressBase(SDValue N, X86ISelAddressMode &AM); bool SelectAddr(SDNode *Parent, SDValue N, SDValue &Base, SDValue &Scale, SDValue &Index, SDValue &Disp, SDValue &Segment); bool SelectMOV64Imm32(SDValue N, SDValue &Imm); bool SelectLEAAddr(SDValue N, SDValue &Base, SDValue &Scale, SDValue &Index, SDValue &Disp, SDValue &Segment); bool SelectLEA64_32Addr(SDValue N, SDValue &Base, SDValue &Scale, SDValue &Index, SDValue &Disp, SDValue &Segment); bool SelectTLSADDRAddr(SDValue N, SDValue &Base, SDValue &Scale, SDValue &Index, SDValue &Disp, SDValue &Segment); bool SelectScalarSSELoad(SDNode *Root, SDValue N, SDValue &Base, SDValue &Scale, SDValue &Index, SDValue &Disp, SDValue &Segment, SDValue &NodeWithChain); bool TryFoldLoad(SDNode *P, SDValue N, SDValue &Base, SDValue &Scale, SDValue &Index, SDValue &Disp, SDValue &Segment); /// SelectInlineAsmMemoryOperand - Implement addressing mode selection for /// inline asm expressions. bool SelectInlineAsmMemoryOperand(const SDValue &Op, char ConstraintCode, std::vector &OutOps) override; void EmitSpecialCodeForMain(MachineBasicBlock *BB, MachineFrameInfo *MFI); inline void getAddressOperands(X86ISelAddressMode &AM, SDValue &Base, SDValue &Scale, SDValue &Index, SDValue &Disp, SDValue &Segment) { Base = (AM.BaseType == X86ISelAddressMode::FrameIndexBase) ? CurDAG->getTargetFrameIndex(AM.Base_FrameIndex, getTargetLowering()->getPointerTy()) : AM.Base_Reg; Scale = getI8Imm(AM.Scale); Index = AM.IndexReg; // These are 32-bit even in 64-bit mode since RIP relative offset // is 32-bit. if (AM.GV) Disp = CurDAG->getTargetGlobalAddress(AM.GV, SDLoc(), MVT::i32, AM.Disp, AM.SymbolFlags); else if (AM.CP) Disp = CurDAG->getTargetConstantPool(AM.CP, MVT::i32, AM.Align, AM.Disp, AM.SymbolFlags); else if (AM.ES) { assert(!AM.Disp && "Non-zero displacement is ignored with ES."); Disp = CurDAG->getTargetExternalSymbol(AM.ES, MVT::i32, AM.SymbolFlags); } else if (AM.JT != -1) { assert(!AM.Disp && "Non-zero displacement is ignored with JT."); Disp = CurDAG->getTargetJumpTable(AM.JT, MVT::i32, AM.SymbolFlags); } else if (AM.BlockAddr) Disp = CurDAG->getTargetBlockAddress(AM.BlockAddr, MVT::i32, AM.Disp, AM.SymbolFlags); else Disp = CurDAG->getTargetConstant(AM.Disp, MVT::i32); if (AM.Segment.getNode()) Segment = AM.Segment; else Segment = CurDAG->getRegister(0, MVT::i32); } /// getI8Imm - Return a target constant with the specified value, of type /// i8. inline SDValue getI8Imm(unsigned Imm) { return CurDAG->getTargetConstant(Imm, MVT::i8); } /// getI32Imm - Return a target constant with the specified value, of type /// i32. inline SDValue getI32Imm(unsigned Imm) { return CurDAG->getTargetConstant(Imm, MVT::i32); } /// getGlobalBaseReg - Return an SDNode that returns the value of /// the global base register. Output instructions required to /// initialize the global base register, if necessary. /// SDNode *getGlobalBaseReg(); /// getTargetMachine - Return a reference to the TargetMachine, casted /// to the target-specific type. const X86TargetMachine &getTargetMachine() const { return static_cast(TM); } /// getInstrInfo - Return a reference to the TargetInstrInfo, casted /// to the target-specific type. const X86InstrInfo *getInstrInfo() const { return getTargetMachine().getInstrInfo(); } }; } bool X86DAGToDAGISel::IsProfitableToFold(SDValue N, SDNode *U, SDNode *Root) const { if (OptLevel == CodeGenOpt::None) return false; if (!N.hasOneUse()) return false; if (N.getOpcode() != ISD::LOAD) return true; // If N is a load, do additional profitability checks. if (U == Root) { switch (U->getOpcode()) { default: break; case X86ISD::ADD: case X86ISD::SUB: case X86ISD::AND: case X86ISD::XOR: case X86ISD::OR: case ISD::ADD: case ISD::ADDC: case ISD::ADDE: case ISD::AND: case ISD::OR: case ISD::XOR: { SDValue Op1 = U->getOperand(1); // If the other operand is a 8-bit immediate we should fold the immediate // instead. This reduces code size. // e.g. // movl 4(%esp), %eax // addl $4, %eax // vs. // movl $4, %eax // addl 4(%esp), %eax // The former is 2 bytes shorter. In case where the increment is 1, then // the saving can be 4 bytes (by using incl %eax). if (ConstantSDNode *Imm = dyn_cast(Op1)) if (Imm->getAPIntValue().isSignedIntN(8)) return false; // If the other operand is a TLS address, we should fold it instead. // This produces // movl %gs:0, %eax // leal i@NTPOFF(%eax), %eax // instead of // movl $i@NTPOFF, %eax // addl %gs:0, %eax // if the block also has an access to a second TLS address this will save // a load. // FIXME: This is probably also true for non-TLS addresses. if (Op1.getOpcode() == X86ISD::Wrapper) { SDValue Val = Op1.getOperand(0); if (Val.getOpcode() == ISD::TargetGlobalTLSAddress) return false; } } } } return true; } /// MoveBelowCallOrigChain - Replace the original chain operand of the call with /// load's chain operand and move load below the call's chain operand. static void MoveBelowOrigChain(SelectionDAG *CurDAG, SDValue Load, SDValue Call, SDValue OrigChain) { SmallVector Ops; SDValue Chain = OrigChain.getOperand(0); if (Chain.getNode() == Load.getNode()) Ops.push_back(Load.getOperand(0)); else { assert(Chain.getOpcode() == ISD::TokenFactor && "Unexpected chain operand"); for (unsigned i = 0, e = Chain.getNumOperands(); i != e; ++i) if (Chain.getOperand(i).getNode() == Load.getNode()) Ops.push_back(Load.getOperand(0)); else Ops.push_back(Chain.getOperand(i)); SDValue NewChain = CurDAG->getNode(ISD::TokenFactor, SDLoc(Load), MVT::Other, Ops); Ops.clear(); Ops.push_back(NewChain); } for (unsigned i = 1, e = OrigChain.getNumOperands(); i != e; ++i) Ops.push_back(OrigChain.getOperand(i)); CurDAG->UpdateNodeOperands(OrigChain.getNode(), Ops); CurDAG->UpdateNodeOperands(Load.getNode(), Call.getOperand(0), Load.getOperand(1), Load.getOperand(2)); unsigned NumOps = Call.getNode()->getNumOperands(); Ops.clear(); Ops.push_back(SDValue(Load.getNode(), 1)); for (unsigned i = 1, e = NumOps; i != e; ++i) Ops.push_back(Call.getOperand(i)); CurDAG->UpdateNodeOperands(Call.getNode(), Ops); } /// isCalleeLoad - Return true if call address is a load and it can be /// moved below CALLSEQ_START and the chains leading up to the call. /// Return the CALLSEQ_START by reference as a second output. /// In the case of a tail call, there isn't a callseq node between the call /// chain and the load. static bool isCalleeLoad(SDValue Callee, SDValue &Chain, bool HasCallSeq) { // The transformation is somewhat dangerous if the call's chain was glued to // the call. After MoveBelowOrigChain the load is moved between the call and // the chain, this can create a cycle if the load is not folded. So it is // *really* important that we are sure the load will be folded. if (Callee.getNode() == Chain.getNode() || !Callee.hasOneUse()) return false; LoadSDNode *LD = dyn_cast(Callee.getNode()); if (!LD || LD->isVolatile() || LD->getAddressingMode() != ISD::UNINDEXED || LD->getExtensionType() != ISD::NON_EXTLOAD) return false; // Now let's find the callseq_start. while (HasCallSeq && Chain.getOpcode() != ISD::CALLSEQ_START) { if (!Chain.hasOneUse()) return false; Chain = Chain.getOperand(0); } if (!Chain.getNumOperands()) return false; // Since we are not checking for AA here, conservatively abort if the chain // writes to memory. It's not safe to move the callee (a load) across a store. if (isa(Chain.getNode()) && cast(Chain.getNode())->writeMem()) return false; if (Chain.getOperand(0).getNode() == Callee.getNode()) return true; if (Chain.getOperand(0).getOpcode() == ISD::TokenFactor && Callee.getValue(1).isOperandOf(Chain.getOperand(0).getNode()) && Callee.getValue(1).hasOneUse()) return true; return false; } void X86DAGToDAGISel::PreprocessISelDAG() { // OptForSize is used in pattern predicates that isel is matching. OptForSize = MF->getFunction()->getAttributes(). hasAttribute(AttributeSet::FunctionIndex, Attribute::OptimizeForSize); for (SelectionDAG::allnodes_iterator I = CurDAG->allnodes_begin(), E = CurDAG->allnodes_end(); I != E; ) { SDNode *N = I++; // Preincrement iterator to avoid invalidation issues. if (OptLevel != CodeGenOpt::None && // Only does this when target favors doesn't favor register indirect // call. ((N->getOpcode() == X86ISD::CALL && !Subtarget->callRegIndirect()) || (N->getOpcode() == X86ISD::TC_RETURN && // Only does this if load can be folded into TC_RETURN. (Subtarget->is64Bit() || getTargetMachine().getRelocationModel() != Reloc::PIC_)))) { /// Also try moving call address load from outside callseq_start to just /// before the call to allow it to be folded. /// /// [Load chain] /// ^ /// | /// [Load] /// ^ ^ /// | | /// / \-- /// / | ///[CALLSEQ_START] | /// ^ | /// | | /// [LOAD/C2Reg] | /// | | /// \ / /// \ / /// [CALL] bool HasCallSeq = N->getOpcode() == X86ISD::CALL; SDValue Chain = N->getOperand(0); SDValue Load = N->getOperand(1); if (!isCalleeLoad(Load, Chain, HasCallSeq)) continue; MoveBelowOrigChain(CurDAG, Load, SDValue(N, 0), Chain); ++NumLoadMoved; continue; } // Lower fpround and fpextend nodes that target the FP stack to be store and // load to the stack. This is a gross hack. We would like to simply mark // these as being illegal, but when we do that, legalize produces these when // it expands calls, then expands these in the same legalize pass. We would // like dag combine to be able to hack on these between the call expansion // and the node legalization. As such this pass basically does "really // late" legalization of these inline with the X86 isel pass. // FIXME: This should only happen when not compiled with -O0. if (N->getOpcode() != ISD::FP_ROUND && N->getOpcode() != ISD::FP_EXTEND) continue; MVT SrcVT = N->getOperand(0).getSimpleValueType(); MVT DstVT = N->getSimpleValueType(0); // If any of the sources are vectors, no fp stack involved. if (SrcVT.isVector() || DstVT.isVector()) continue; // If the source and destination are SSE registers, then this is a legal // conversion that should not be lowered. const X86TargetLowering *X86Lowering = static_cast(getTargetLowering()); bool SrcIsSSE = X86Lowering->isScalarFPTypeInSSEReg(SrcVT); bool DstIsSSE = X86Lowering->isScalarFPTypeInSSEReg(DstVT); if (SrcIsSSE && DstIsSSE) continue; if (!SrcIsSSE && !DstIsSSE) { // If this is an FPStack extension, it is a noop. if (N->getOpcode() == ISD::FP_EXTEND) continue; // If this is a value-preserving FPStack truncation, it is a noop. if (N->getConstantOperandVal(1)) continue; } // Here we could have an FP stack truncation or an FPStack <-> SSE convert. // FPStack has extload and truncstore. SSE can fold direct loads into other // operations. Based on this, decide what we want to do. MVT MemVT; if (N->getOpcode() == ISD::FP_ROUND) MemVT = DstVT; // FP_ROUND must use DstVT, we can't do a 'trunc load'. else MemVT = SrcIsSSE ? SrcVT : DstVT; SDValue MemTmp = CurDAG->CreateStackTemporary(MemVT); SDLoc dl(N); // FIXME: optimize the case where the src/dest is a load or store? SDValue Store = CurDAG->getTruncStore(CurDAG->getEntryNode(), dl, N->getOperand(0), MemTmp, MachinePointerInfo(), MemVT, false, false, 0); SDValue Result = CurDAG->getExtLoad(ISD::EXTLOAD, dl, DstVT, Store, MemTmp, MachinePointerInfo(), MemVT, false, false, 0); // We're about to replace all uses of the FP_ROUND/FP_EXTEND with the // extload we created. This will cause general havok on the dag because // anything below the conversion could be folded into other existing nodes. // To avoid invalidating 'I', back it up to the convert node. --I; CurDAG->ReplaceAllUsesOfValueWith(SDValue(N, 0), Result); // Now that we did that, the node is dead. Increment the iterator to the // next node to process, then delete N. ++I; CurDAG->DeleteNode(N); } } /// EmitSpecialCodeForMain - Emit any code that needs to be executed only in /// the main function. void X86DAGToDAGISel::EmitSpecialCodeForMain(MachineBasicBlock *BB, MachineFrameInfo *MFI) { const TargetInstrInfo *TII = TM.getInstrInfo(); if (Subtarget->isTargetCygMing()) { unsigned CallOp = Subtarget->is64Bit() ? X86::CALL64pcrel32 : X86::CALLpcrel32; BuildMI(BB, DebugLoc(), TII->get(CallOp)).addExternalSymbol("__main"); } } void X86DAGToDAGISel::EmitFunctionEntryCode() { // If this is main, emit special code for main. if (const Function *Fn = MF->getFunction()) if (Fn->hasExternalLinkage() && Fn->getName() == "main") EmitSpecialCodeForMain(MF->begin(), MF->getFrameInfo()); } static bool isDispSafeForFrameIndex(int64_t Val) { // On 64-bit platforms, we can run into an issue where a frame index // includes a displacement that, when added to the explicit displacement, // will overflow the displacement field. Assuming that the frame index // displacement fits into a 31-bit integer (which is only slightly more // aggressive than the current fundamental assumption that it fits into // a 32-bit integer), a 31-bit disp should always be safe. return isInt<31>(Val); } bool X86DAGToDAGISel::FoldOffsetIntoAddress(uint64_t Offset, X86ISelAddressMode &AM) { int64_t Val = AM.Disp + Offset; CodeModel::Model M = TM.getCodeModel(); if (Subtarget->is64Bit()) { if (!X86::isOffsetSuitableForCodeModel(Val, M, AM.hasSymbolicDisplacement())) return true; // In addition to the checks required for a register base, check that // we do not try to use an unsafe Disp with a frame index. if (AM.BaseType == X86ISelAddressMode::FrameIndexBase && !isDispSafeForFrameIndex(Val)) return true; } AM.Disp = Val; return false; } bool X86DAGToDAGISel::MatchLoadInAddress(LoadSDNode *N, X86ISelAddressMode &AM){ SDValue Address = N->getOperand(1); // load gs:0 -> GS segment register. // load fs:0 -> FS segment register. // // This optimization is valid because the GNU TLS model defines that // gs:0 (or fs:0 on X86-64) contains its own address. // For more information see http://people.redhat.com/drepper/tls.pdf if (ConstantSDNode *C = dyn_cast(Address)) if (C->getSExtValue() == 0 && AM.Segment.getNode() == nullptr && Subtarget->isTargetLinux()) switch (N->getPointerInfo().getAddrSpace()) { case 256: AM.Segment = CurDAG->getRegister(X86::GS, MVT::i16); return false; case 257: AM.Segment = CurDAG->getRegister(X86::FS, MVT::i16); return false; } return true; } /// MatchWrapper - Try to match X86ISD::Wrapper and X86ISD::WrapperRIP nodes /// into an addressing mode. These wrap things that will resolve down into a /// symbol reference. If no match is possible, this returns true, otherwise it /// returns false. bool X86DAGToDAGISel::MatchWrapper(SDValue N, X86ISelAddressMode &AM) { // If the addressing mode already has a symbol as the displacement, we can // never match another symbol. if (AM.hasSymbolicDisplacement()) return true; SDValue N0 = N.getOperand(0); CodeModel::Model M = TM.getCodeModel(); // Handle X86-64 rip-relative addresses. We check this before checking direct // folding because RIP is preferable to non-RIP accesses. if (Subtarget->is64Bit() && N.getOpcode() == X86ISD::WrapperRIP && // Under X86-64 non-small code model, GV (and friends) are 64-bits, so // they cannot be folded into immediate fields. // FIXME: This can be improved for kernel and other models? (M == CodeModel::Small || M == CodeModel::Kernel)) { // Base and index reg must be 0 in order to use %rip as base. if (AM.hasBaseOrIndexReg()) return true; if (GlobalAddressSDNode *G = dyn_cast(N0)) { X86ISelAddressMode Backup = AM; AM.GV = G->getGlobal(); AM.SymbolFlags = G->getTargetFlags(); if (FoldOffsetIntoAddress(G->getOffset(), AM)) { AM = Backup; return true; } } else if (ConstantPoolSDNode *CP = dyn_cast(N0)) { X86ISelAddressMode Backup = AM; AM.CP = CP->getConstVal(); AM.Align = CP->getAlignment(); AM.SymbolFlags = CP->getTargetFlags(); if (FoldOffsetIntoAddress(CP->getOffset(), AM)) { AM = Backup; return true; } } else if (ExternalSymbolSDNode *S = dyn_cast(N0)) { AM.ES = S->getSymbol(); AM.SymbolFlags = S->getTargetFlags(); } else if (JumpTableSDNode *J = dyn_cast(N0)) { AM.JT = J->getIndex(); AM.SymbolFlags = J->getTargetFlags(); } else if (BlockAddressSDNode *BA = dyn_cast(N0)) { X86ISelAddressMode Backup = AM; AM.BlockAddr = BA->getBlockAddress(); AM.SymbolFlags = BA->getTargetFlags(); if (FoldOffsetIntoAddress(BA->getOffset(), AM)) { AM = Backup; return true; } } else llvm_unreachable("Unhandled symbol reference node."); if (N.getOpcode() == X86ISD::WrapperRIP) AM.setBaseReg(CurDAG->getRegister(X86::RIP, MVT::i64)); return false; } // Handle the case when globals fit in our immediate field: This is true for // X86-32 always and X86-64 when in -mcmodel=small mode. In 64-bit // mode, this only applies to a non-RIP-relative computation. if (!Subtarget->is64Bit() || M == CodeModel::Small || M == CodeModel::Kernel) { assert(N.getOpcode() != X86ISD::WrapperRIP && "RIP-relative addressing already handled"); if (GlobalAddressSDNode *G = dyn_cast(N0)) { AM.GV = G->getGlobal(); AM.Disp += G->getOffset(); AM.SymbolFlags = G->getTargetFlags(); } else if (ConstantPoolSDNode *CP = dyn_cast(N0)) { AM.CP = CP->getConstVal(); AM.Align = CP->getAlignment(); AM.Disp += CP->getOffset(); AM.SymbolFlags = CP->getTargetFlags(); } else if (ExternalSymbolSDNode *S = dyn_cast(N0)) { AM.ES = S->getSymbol(); AM.SymbolFlags = S->getTargetFlags(); } else if (JumpTableSDNode *J = dyn_cast(N0)) { AM.JT = J->getIndex(); AM.SymbolFlags = J->getTargetFlags(); } else if (BlockAddressSDNode *BA = dyn_cast(N0)) { AM.BlockAddr = BA->getBlockAddress(); AM.Disp += BA->getOffset(); AM.SymbolFlags = BA->getTargetFlags(); } else llvm_unreachable("Unhandled symbol reference node."); return false; } return true; } /// MatchAddress - Add the specified node to the specified addressing mode, /// returning true if it cannot be done. This just pattern matches for the /// addressing mode. bool X86DAGToDAGISel::MatchAddress(SDValue N, X86ISelAddressMode &AM) { if (MatchAddressRecursively(N, AM, 0)) return true; // Post-processing: Convert lea(,%reg,2) to lea(%reg,%reg), which has // a smaller encoding and avoids a scaled-index. if (AM.Scale == 2 && AM.BaseType == X86ISelAddressMode::RegBase && AM.Base_Reg.getNode() == nullptr) { AM.Base_Reg = AM.IndexReg; AM.Scale = 1; } // Post-processing: Convert foo to foo(%rip), even in non-PIC mode, // because it has a smaller encoding. // TODO: Which other code models can use this? if (TM.getCodeModel() == CodeModel::Small && Subtarget->is64Bit() && AM.Scale == 1 && AM.BaseType == X86ISelAddressMode::RegBase && AM.Base_Reg.getNode() == nullptr && AM.IndexReg.getNode() == nullptr && AM.SymbolFlags == X86II::MO_NO_FLAG && AM.hasSymbolicDisplacement()) AM.Base_Reg = CurDAG->getRegister(X86::RIP, MVT::i64); return false; } // Insert a node into the DAG at least before the Pos node's position. This // will reposition the node as needed, and will assign it a node ID that is <= // the Pos node'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 // is used. static void InsertDAGNode(SelectionDAG &DAG, SDValue Pos, SDValue N) { if (N.getNode()->getNodeId() == -1 || N.getNode()->getNodeId() > Pos.getNode()->getNodeId()) { DAG.RepositionNode(Pos.getNode(), N.getNode()); N.getNode()->setNodeId(Pos.getNode()->getNodeId()); } } // Transform "(X >> (8-C1)) & C2" to "(X >> 8) & 0xff)" if safe. This // allows us to convert the shift and and into an h-register extract and // a scaled index. Returns false if the simplification is performed. static bool FoldMaskAndShiftToExtract(SelectionDAG &DAG, SDValue N, uint64_t Mask, SDValue Shift, SDValue X, X86ISelAddressMode &AM) { if (Shift.getOpcode() != ISD::SRL || !isa(Shift.getOperand(1)) || !Shift.hasOneUse()) return true; int ScaleLog = 8 - Shift.getConstantOperandVal(1); if (ScaleLog <= 0 || ScaleLog >= 4 || Mask != (0xffu << ScaleLog)) return true; MVT VT = N.getSimpleValueType(); SDLoc DL(N); SDValue Eight = DAG.getConstant(8, MVT::i8); SDValue NewMask = DAG.getConstant(0xff, VT); SDValue Srl = DAG.getNode(ISD::SRL, DL, VT, X, Eight); SDValue And = DAG.getNode(ISD::AND, DL, VT, Srl, NewMask); SDValue ShlCount = DAG.getConstant(ScaleLog, MVT::i8); SDValue Shl = DAG.getNode(ISD::SHL, DL, VT, And, ShlCount); // Insert the new nodes into the topological ordering. We must do this in // a valid topological ordering as nothing is going to go back and re-sort // these nodes. We continually insert before 'N' in sequence as this is // essentially a pre-flattened and pre-sorted sequence of nodes. There is no // hierarchy left to express. InsertDAGNode(DAG, N, Eight); InsertDAGNode(DAG, N, Srl); InsertDAGNode(DAG, N, NewMask); InsertDAGNode(DAG, N, And); InsertDAGNode(DAG, N, ShlCount); InsertDAGNode(DAG, N, Shl); DAG.ReplaceAllUsesWith(N, Shl); AM.IndexReg = And; AM.Scale = (1 << ScaleLog); return false; } // Transforms "(X << C1) & C2" to "(X & (C2>>C1)) << C1" if safe and if this // allows us to fold the shift into this addressing mode. Returns false if the // transform succeeded. static bool FoldMaskedShiftToScaledMask(SelectionDAG &DAG, SDValue N, uint64_t Mask, SDValue Shift, SDValue X, X86ISelAddressMode &AM) { if (Shift.getOpcode() != ISD::SHL || !isa(Shift.getOperand(1))) return true; // Not likely to be profitable if either the AND or SHIFT node has more // than one use (unless all uses are for address computation). Besides, // isel mechanism requires their node ids to be reused. if (!N.hasOneUse() || !Shift.hasOneUse()) return true; // Verify that the shift amount is something we can fold. unsigned ShiftAmt = Shift.getConstantOperandVal(1); if (ShiftAmt != 1 && ShiftAmt != 2 && ShiftAmt != 3) return true; MVT VT = N.getSimpleValueType(); SDLoc DL(N); SDValue NewMask = DAG.getConstant(Mask >> ShiftAmt, VT); SDValue NewAnd = DAG.getNode(ISD::AND, DL, VT, X, NewMask); SDValue NewShift = DAG.getNode(ISD::SHL, DL, VT, NewAnd, Shift.getOperand(1)); // Insert the new nodes into the topological ordering. We must do this in // a valid topological ordering as nothing is going to go back and re-sort // these nodes. We continually insert before 'N' in sequence as this is // essentially a pre-flattened and pre-sorted sequence of nodes. There is no // hierarchy left to express. InsertDAGNode(DAG, N, NewMask); InsertDAGNode(DAG, N, NewAnd); InsertDAGNode(DAG, N, NewShift); DAG.ReplaceAllUsesWith(N, NewShift); AM.Scale = 1 << ShiftAmt; AM.IndexReg = NewAnd; return false; } // Implement some heroics to detect shifts of masked values where the mask can // be replaced by extending the shift and undoing that in the addressing mode // scale. Patterns such as (shl (srl x, c1), c2) are canonicalized into (and // (srl x, SHIFT), MASK) by DAGCombines that don't know the shl can be done in // the addressing mode. This results in code such as: // // int f(short *y, int *lookup_table) { // ... // return *y + lookup_table[*y >> 11]; // } // // Turning into: // movzwl (%rdi), %eax // movl %eax, %ecx // shrl $11, %ecx // addl (%rsi,%rcx,4), %eax // // Instead of: // movzwl (%rdi), %eax // movl %eax, %ecx // shrl $9, %ecx // andl $124, %rcx // addl (%rsi,%rcx), %eax // // Note that this function assumes the mask is provided as a mask *after* the // value is shifted. The input chain may or may not match that, but computing // such a mask is trivial. static bool FoldMaskAndShiftToScale(SelectionDAG &DAG, SDValue N, uint64_t Mask, SDValue Shift, SDValue X, X86ISelAddressMode &AM) { if (Shift.getOpcode() != ISD::SRL || !Shift.hasOneUse() || !isa(Shift.getOperand(1))) return true; unsigned ShiftAmt = Shift.getConstantOperandVal(1); unsigned MaskLZ = countLeadingZeros(Mask); unsigned MaskTZ = countTrailingZeros(Mask); // The amount of shift we're trying to fit into the addressing mode is taken // from the trailing zeros of the mask. unsigned AMShiftAmt = MaskTZ; // There is nothing we can do here unless the mask is removing some bits. // Also, the addressing mode can only represent shifts of 1, 2, or 3 bits. if (AMShiftAmt <= 0 || AMShiftAmt > 3) return true; // We also need to ensure that mask is a continuous run of bits. if (CountTrailingOnes_64(Mask >> MaskTZ) + MaskTZ + MaskLZ != 64) return true; // Scale the leading zero count down based on the actual size of the value. // Also scale it down based on the size of the shift. MaskLZ -= (64 - X.getSimpleValueType().getSizeInBits()) + ShiftAmt; // The final check is to ensure that any masked out high bits of X are // already known to be zero. Otherwise, the mask has a semantic impact // other than masking out a couple of low bits. Unfortunately, because of // the mask, zero extensions will be removed from operands in some cases. // This code works extra hard to look through extensions because we can // replace them with zero extensions cheaply if necessary. bool ReplacingAnyExtend = false; if (X.getOpcode() == ISD::ANY_EXTEND) { unsigned ExtendBits = X.getSimpleValueType().getSizeInBits() - X.getOperand(0).getSimpleValueType().getSizeInBits(); // Assume that we'll replace the any-extend with a zero-extend, and // narrow the search to the extended value. X = X.getOperand(0); MaskLZ = ExtendBits > MaskLZ ? 0 : MaskLZ - ExtendBits; ReplacingAnyExtend = true; } APInt MaskedHighBits = APInt::getHighBitsSet(X.getSimpleValueType().getSizeInBits(), MaskLZ); APInt KnownZero, KnownOne; DAG.computeKnownBits(X, KnownZero, KnownOne); if (MaskedHighBits != KnownZero) return true; // We've identified a pattern that can be transformed into a single shift // and an addressing mode. Make it so. MVT VT = N.getSimpleValueType(); if (ReplacingAnyExtend) { assert(X.getValueType() != VT); // We looked through an ANY_EXTEND node, insert a ZERO_EXTEND. SDValue NewX = DAG.getNode(ISD::ZERO_EXTEND, SDLoc(X), VT, X); InsertDAGNode(DAG, N, NewX); X = NewX; } SDLoc DL(N); SDValue NewSRLAmt = DAG.getConstant(ShiftAmt + AMShiftAmt, MVT::i8); SDValue NewSRL = DAG.getNode(ISD::SRL, DL, VT, X, NewSRLAmt); SDValue NewSHLAmt = DAG.getConstant(AMShiftAmt, MVT::i8); SDValue NewSHL = DAG.getNode(ISD::SHL, DL, VT, NewSRL, NewSHLAmt); // Insert the new nodes into the topological ordering. We must do this in // a valid topological ordering as nothing is going to go back and re-sort // these nodes. We continually insert before 'N' in sequence as this is // essentially a pre-flattened and pre-sorted sequence of nodes. There is no // hierarchy left to express. InsertDAGNode(DAG, N, NewSRLAmt); InsertDAGNode(DAG, N, NewSRL); InsertDAGNode(DAG, N, NewSHLAmt); InsertDAGNode(DAG, N, NewSHL); DAG.ReplaceAllUsesWith(N, NewSHL); AM.Scale = 1 << AMShiftAmt; AM.IndexReg = NewSRL; return false; } bool X86DAGToDAGISel::MatchAddressRecursively(SDValue N, X86ISelAddressMode &AM, unsigned Depth) { SDLoc dl(N); DEBUG({ dbgs() << "MatchAddress: "; AM.dump(); }); // Limit recursion. if (Depth > 5) return MatchAddressBase(N, AM); // If this is already a %rip relative address, we can only merge immediates // into it. Instead of handling this in every case, we handle it here. // RIP relative addressing: %rip + 32-bit displacement! if (AM.isRIPRelative()) { // FIXME: JumpTable and ExternalSymbol address currently don't like // displacements. It isn't very important, but this should be fixed for // consistency. if (!AM.ES && AM.JT != -1) return true; if (ConstantSDNode *Cst = dyn_cast(N)) if (!FoldOffsetIntoAddress(Cst->getSExtValue(), AM)) return false; return true; } switch (N.getOpcode()) { default: break; case ISD::Constant: { uint64_t Val = cast(N)->getSExtValue(); if (!FoldOffsetIntoAddress(Val, AM)) return false; break; } case X86ISD::Wrapper: case X86ISD::WrapperRIP: if (!MatchWrapper(N, AM)) return false; break; case ISD::LOAD: if (!MatchLoadInAddress(cast(N), AM)) return false; break; case ISD::FrameIndex: if (AM.BaseType == X86ISelAddressMode::RegBase && AM.Base_Reg.getNode() == nullptr && (!Subtarget->is64Bit() || isDispSafeForFrameIndex(AM.Disp))) { AM.BaseType = X86ISelAddressMode::FrameIndexBase; AM.Base_FrameIndex = cast(N)->getIndex(); return false; } break; case ISD::SHL: if (AM.IndexReg.getNode() != nullptr || AM.Scale != 1) break; if (ConstantSDNode *CN = dyn_cast(N.getNode()->getOperand(1))) { unsigned Val = CN->getZExtValue(); // Note that we handle x<<1 as (,x,2) rather than (x,x) here so // that the base operand remains free for further matching. If // the base doesn't end up getting used, a post-processing step // in MatchAddress turns (,x,2) into (x,x), which is cheaper. if (Val == 1 || Val == 2 || Val == 3) { AM.Scale = 1 << Val; SDValue ShVal = N.getNode()->getOperand(0); // Okay, we know that we have a scale by now. However, if the scaled // value is an add of something and a constant, we can fold the // constant into the disp field here. if (CurDAG->isBaseWithConstantOffset(ShVal)) { AM.IndexReg = ShVal.getNode()->getOperand(0); ConstantSDNode *AddVal = cast(ShVal.getNode()->getOperand(1)); uint64_t Disp = (uint64_t)AddVal->getSExtValue() << Val; if (!FoldOffsetIntoAddress(Disp, AM)) return false; } AM.IndexReg = ShVal; return false; } } break; case ISD::SRL: { // Scale must not be used already. if (AM.IndexReg.getNode() != nullptr || AM.Scale != 1) break; SDValue And = N.getOperand(0); if (And.getOpcode() != ISD::AND) break; SDValue X = And.getOperand(0); // We only handle up to 64-bit values here as those are what matter for // addressing mode optimizations. if (X.getSimpleValueType().getSizeInBits() > 64) break; // The mask used for the transform is expected to be post-shift, but we // found the shift first so just apply the shift to the mask before passing // it down. if (!isa(N.getOperand(1)) || !isa(And.getOperand(1))) break; uint64_t Mask = And.getConstantOperandVal(1) >> N.getConstantOperandVal(1); // Try to fold the mask and shift into the scale, and return false if we // succeed. if (!FoldMaskAndShiftToScale(*CurDAG, N, Mask, N, X, AM)) return false; break; } case ISD::SMUL_LOHI: case ISD::UMUL_LOHI: // A mul_lohi where we need the low part can be folded as a plain multiply. if (N.getResNo() != 0) break; // FALL THROUGH case ISD::MUL: case X86ISD::MUL_IMM: // X*[3,5,9] -> X+X*[2,4,8] if (AM.BaseType == X86ISelAddressMode::RegBase && AM.Base_Reg.getNode() == nullptr && AM.IndexReg.getNode() == nullptr) { if (ConstantSDNode *CN = dyn_cast(N.getNode()->getOperand(1))) if (CN->getZExtValue() == 3 || CN->getZExtValue() == 5 || CN->getZExtValue() == 9) { AM.Scale = unsigned(CN->getZExtValue())-1; SDValue MulVal = N.getNode()->getOperand(0); SDValue Reg; // Okay, we know that we have a scale by now. However, if the scaled // value is an add of something and a constant, we can fold the // constant into the disp field here. if (MulVal.getNode()->getOpcode() == ISD::ADD && MulVal.hasOneUse() && isa(MulVal.getNode()->getOperand(1))) { Reg = MulVal.getNode()->getOperand(0); ConstantSDNode *AddVal = cast(MulVal.getNode()->getOperand(1)); uint64_t Disp = AddVal->getSExtValue() * CN->getZExtValue(); if (FoldOffsetIntoAddress(Disp, AM)) Reg = N.getNode()->getOperand(0); } else { Reg = N.getNode()->getOperand(0); } AM.IndexReg = AM.Base_Reg = Reg; return false; } } break; case ISD::SUB: { // Given A-B, if A can be completely folded into the address and // the index field with the index field unused, use -B as the index. // This is a win if a has multiple parts that can be folded into // the address. Also, this saves a mov if the base register has // other uses, since it avoids a two-address sub instruction, however // it costs an additional mov if the index register has other uses. // Add an artificial use to this node so that we can keep track of // it if it gets CSE'd with a different node. HandleSDNode Handle(N); // Test if the LHS of the sub can be folded. X86ISelAddressMode Backup = AM; if (MatchAddressRecursively(N.getNode()->getOperand(0), AM, Depth+1)) { AM = Backup; break; } // Test if the index field is free for use. if (AM.IndexReg.getNode() || AM.isRIPRelative()) { AM = Backup; break; } int Cost = 0; SDValue RHS = Handle.getValue().getNode()->getOperand(1); // If the RHS involves a register with multiple uses, this // transformation incurs an extra mov, due to the neg instruction // clobbering its operand. if (!RHS.getNode()->hasOneUse() || RHS.getNode()->getOpcode() == ISD::CopyFromReg || RHS.getNode()->getOpcode() == ISD::TRUNCATE || RHS.getNode()->getOpcode() == ISD::ANY_EXTEND || (RHS.getNode()->getOpcode() == ISD::ZERO_EXTEND && RHS.getNode()->getOperand(0).getValueType() == MVT::i32)) ++Cost; // If the base is a register with multiple uses, this // transformation may save a mov. if ((AM.BaseType == X86ISelAddressMode::RegBase && AM.Base_Reg.getNode() && !AM.Base_Reg.getNode()->hasOneUse()) || AM.BaseType == X86ISelAddressMode::FrameIndexBase) --Cost; // If the folded LHS was interesting, this transformation saves // address arithmetic. if ((AM.hasSymbolicDisplacement() && !Backup.hasSymbolicDisplacement()) + ((AM.Disp != 0) && (Backup.Disp == 0)) + (AM.Segment.getNode() && !Backup.Segment.getNode()) >= 2) --Cost; // If it doesn't look like it may be an overall win, don't do it. if (Cost >= 0) { AM = Backup; break; } // Ok, the transformation is legal and appears profitable. Go for it. SDValue Zero = CurDAG->getConstant(0, N.getValueType()); SDValue Neg = CurDAG->getNode(ISD::SUB, dl, N.getValueType(), Zero, RHS); AM.IndexReg = Neg; AM.Scale = 1; // Insert the new nodes into the topological ordering. InsertDAGNode(*CurDAG, N, Zero); InsertDAGNode(*CurDAG, N, Neg); return false; } case ISD::ADD: { // Add an artificial use to this node so that we can keep track of // it if it gets CSE'd with a different node. HandleSDNode Handle(N); X86ISelAddressMode Backup = AM; if (!MatchAddressRecursively(N.getOperand(0), AM, Depth+1) && !MatchAddressRecursively(Handle.getValue().getOperand(1), AM, Depth+1)) return false; AM = Backup; // Try again after commuting the operands. if (!MatchAddressRecursively(Handle.getValue().getOperand(1), AM, Depth+1)&& !MatchAddressRecursively(Handle.getValue().getOperand(0), AM, Depth+1)) return false; AM = Backup; // If we couldn't fold both operands into the address at the same time, // see if we can just put each operand into a register and fold at least // the add. if (AM.BaseType == X86ISelAddressMode::RegBase && !AM.Base_Reg.getNode() && !AM.IndexReg.getNode()) { N = Handle.getValue(); AM.Base_Reg = N.getOperand(0); AM.IndexReg = N.getOperand(1); AM.Scale = 1; return false; } N = Handle.getValue(); break; } case ISD::OR: // Handle "X | C" as "X + C" iff X is known to have C bits clear. if (CurDAG->isBaseWithConstantOffset(N)) { X86ISelAddressMode Backup = AM; ConstantSDNode *CN = cast(N.getOperand(1)); // Start with the LHS as an addr mode. if (!MatchAddressRecursively(N.getOperand(0), AM, Depth+1) && !FoldOffsetIntoAddress(CN->getSExtValue(), AM)) return false; AM = Backup; } break; case ISD::AND: { // Perform some heroic transforms on an and of a constant-count shift // with a constant to enable use of the scaled offset field. // Scale must not be used already. if (AM.IndexReg.getNode() != nullptr || AM.Scale != 1) break; SDValue Shift = N.getOperand(0); if (Shift.getOpcode() != ISD::SRL && Shift.getOpcode() != ISD::SHL) break; SDValue X = Shift.getOperand(0); // We only handle up to 64-bit values here as those are what matter for // addressing mode optimizations. if (X.getSimpleValueType().getSizeInBits() > 64) break; if (!isa(N.getOperand(1))) break; uint64_t Mask = N.getConstantOperandVal(1); // Try to fold the mask and shift into an extract and scale. if (!FoldMaskAndShiftToExtract(*CurDAG, N, Mask, Shift, X, AM)) return false; // Try to fold the mask and shift directly into the scale. if (!FoldMaskAndShiftToScale(*CurDAG, N, Mask, Shift, X, AM)) return false; // Try to swap the mask and shift to place shifts which can be done as // a scale on the outside of the mask. if (!FoldMaskedShiftToScaledMask(*CurDAG, N, Mask, Shift, X, AM)) return false; break; } } return MatchAddressBase(N, AM); } /// MatchAddressBase - Helper for MatchAddress. Add the specified node to the /// specified addressing mode without any further recursion. bool X86DAGToDAGISel::MatchAddressBase(SDValue N, X86ISelAddressMode &AM) { // Is the base register already occupied? if (AM.BaseType != X86ISelAddressMode::RegBase || AM.Base_Reg.getNode()) { // If so, check to see if the scale index register is set. if (!AM.IndexReg.getNode()) { AM.IndexReg = N; AM.Scale = 1; return false; } // Otherwise, we cannot select it. return true; } // Default, generate it as a register. AM.BaseType = X86ISelAddressMode::RegBase; AM.Base_Reg = N; return false; } /// SelectAddr - returns true if it is able pattern match an addressing mode. /// It returns the operands which make up the maximal addressing mode it can /// match by reference. /// /// Parent is the parent node of the addr operand that is being matched. It /// is always a load, store, atomic node, or null. It is only null when /// checking memory operands for inline asm nodes. bool X86DAGToDAGISel::SelectAddr(SDNode *Parent, SDValue N, SDValue &Base, SDValue &Scale, SDValue &Index, SDValue &Disp, SDValue &Segment) { X86ISelAddressMode AM; if (Parent && // This list of opcodes are all the nodes that have an "addr:$ptr" operand // that are not a MemSDNode, and thus don't have proper addrspace info. Parent->getOpcode() != ISD::INTRINSIC_W_CHAIN && // unaligned loads, fixme Parent->getOpcode() != ISD::INTRINSIC_VOID && // nontemporal stores Parent->getOpcode() != X86ISD::TLSCALL && // Fixme Parent->getOpcode() != X86ISD::EH_SJLJ_SETJMP && // setjmp Parent->getOpcode() != X86ISD::EH_SJLJ_LONGJMP) { // longjmp unsigned AddrSpace = cast(Parent)->getPointerInfo().getAddrSpace(); // AddrSpace 256 -> GS, 257 -> FS. if (AddrSpace == 256) AM.Segment = CurDAG->getRegister(X86::GS, MVT::i16); if (AddrSpace == 257) AM.Segment = CurDAG->getRegister(X86::FS, MVT::i16); } if (MatchAddress(N, AM)) return false; MVT VT = N.getSimpleValueType(); if (AM.BaseType == X86ISelAddressMode::RegBase) { if (!AM.Base_Reg.getNode()) AM.Base_Reg = CurDAG->getRegister(0, VT); } if (!AM.IndexReg.getNode()) AM.IndexReg = CurDAG->getRegister(0, VT); getAddressOperands(AM, Base, Scale, Index, Disp, Segment); return true; } /// SelectScalarSSELoad - Match a scalar SSE load. In particular, we want to /// match a load whose top elements are either undef or zeros. The load flavor /// is derived from the type of N, which is either v4f32 or v2f64. /// /// We also return: /// PatternChainNode: this is the matched node that has a chain input and /// output. bool X86DAGToDAGISel::SelectScalarSSELoad(SDNode *Root, SDValue N, SDValue &Base, SDValue &Scale, SDValue &Index, SDValue &Disp, SDValue &Segment, SDValue &PatternNodeWithChain) { if (N.getOpcode() == ISD::SCALAR_TO_VECTOR) { PatternNodeWithChain = N.getOperand(0); if (ISD::isNON_EXTLoad(PatternNodeWithChain.getNode()) && PatternNodeWithChain.hasOneUse() && IsProfitableToFold(N.getOperand(0), N.getNode(), Root) && IsLegalToFold(N.getOperand(0), N.getNode(), Root, OptLevel)) { LoadSDNode *LD = cast(PatternNodeWithChain); if (!SelectAddr(LD, LD->getBasePtr(), Base, Scale, Index, Disp, Segment)) return false; return true; } } // Also handle the case where we explicitly require zeros in the top // elements. This is a vector shuffle from the zero vector. if (N.getOpcode() == X86ISD::VZEXT_MOVL && N.getNode()->hasOneUse() && // Check to see if the top elements are all zeros (or bitcast of zeros). N.getOperand(0).getOpcode() == ISD::SCALAR_TO_VECTOR && N.getOperand(0).getNode()->hasOneUse() && ISD::isNON_EXTLoad(N.getOperand(0).getOperand(0).getNode()) && N.getOperand(0).getOperand(0).hasOneUse() && IsProfitableToFold(N.getOperand(0), N.getNode(), Root) && IsLegalToFold(N.getOperand(0), N.getNode(), Root, OptLevel)) { // Okay, this is a zero extending load. Fold it. LoadSDNode *LD = cast(N.getOperand(0).getOperand(0)); if (!SelectAddr(LD, LD->getBasePtr(), Base, Scale, Index, Disp, Segment)) return false; PatternNodeWithChain = SDValue(LD, 0); return true; } return false; } bool X86DAGToDAGISel::SelectMOV64Imm32(SDValue N, SDValue &Imm) { if (const ConstantSDNode *CN = dyn_cast(N)) { uint64_t ImmVal = CN->getZExtValue(); if ((uint32_t)ImmVal != (uint64_t)ImmVal) return false; Imm = CurDAG->getTargetConstant(ImmVal, MVT::i64); return true; } // In static codegen with small code model, we can get the address of a label // into a register with 'movl'. TableGen has already made sure we're looking // at a label of some kind. assert(N->getOpcode() == X86ISD::Wrapper && "Unexpected node type for MOV32ri64"); N = N.getOperand(0); if (N->getOpcode() != ISD::TargetConstantPool && N->getOpcode() != ISD::TargetJumpTable && N->getOpcode() != ISD::TargetGlobalAddress && N->getOpcode() != ISD::TargetExternalSymbol && N->getOpcode() != ISD::TargetBlockAddress) return false; Imm = N; return TM.getCodeModel() == CodeModel::Small; } bool X86DAGToDAGISel::SelectLEA64_32Addr(SDValue N, SDValue &Base, SDValue &Scale, SDValue &Index, SDValue &Disp, SDValue &Segment) { if (!SelectLEAAddr(N, Base, Scale, Index, Disp, Segment)) return false; SDLoc DL(N); RegisterSDNode *RN = dyn_cast(Base); if (RN && RN->getReg() == 0) Base = CurDAG->getRegister(0, MVT::i64); else if (Base.getValueType() == MVT::i32 && !dyn_cast(N)) { // Base could already be %rip, particularly in the x32 ABI. Base = SDValue(CurDAG->getMachineNode( TargetOpcode::SUBREG_TO_REG, DL, MVT::i64, CurDAG->getTargetConstant(0, MVT::i64), Base, CurDAG->getTargetConstant(X86::sub_32bit, MVT::i32)), 0); } RN = dyn_cast(Index); if (RN && RN->getReg() == 0) Index = CurDAG->getRegister(0, MVT::i64); else { assert(Index.getValueType() == MVT::i32 && "Expect to be extending 32-bit registers for use in LEA"); Index = SDValue(CurDAG->getMachineNode( TargetOpcode::SUBREG_TO_REG, DL, MVT::i64, CurDAG->getTargetConstant(0, MVT::i64), Index, CurDAG->getTargetConstant(X86::sub_32bit, MVT::i32)), 0); } return true; } /// SelectLEAAddr - it calls SelectAddr and determines if the maximal addressing /// mode it matches can be cost effectively emitted as an LEA instruction. bool X86DAGToDAGISel::SelectLEAAddr(SDValue N, SDValue &Base, SDValue &Scale, SDValue &Index, SDValue &Disp, SDValue &Segment) { X86ISelAddressMode AM; // Set AM.Segment to prevent MatchAddress from using one. LEA doesn't support // segments. SDValue Copy = AM.Segment; SDValue T = CurDAG->getRegister(0, MVT::i32); AM.Segment = T; if (MatchAddress(N, AM)) return false; assert (T == AM.Segment); AM.Segment = Copy; MVT VT = N.getSimpleValueType(); unsigned Complexity = 0; if (AM.BaseType == X86ISelAddressMode::RegBase) if (AM.Base_Reg.getNode()) Complexity = 1; else AM.Base_Reg = CurDAG->getRegister(0, VT); else if (AM.BaseType == X86ISelAddressMode::FrameIndexBase) Complexity = 4; if (AM.IndexReg.getNode()) Complexity++; else AM.IndexReg = CurDAG->getRegister(0, VT); // Don't match just leal(,%reg,2). It's cheaper to do addl %reg, %reg, or with // a simple shift. if (AM.Scale > 1) Complexity++; // FIXME: We are artificially lowering the criteria to turn ADD %reg, $GA // to a LEA. This is determined with some expermentation but is by no means // optimal (especially for code size consideration). LEA is nice because of // its three-address nature. Tweak the cost function again when we can run // convertToThreeAddress() at register allocation time. if (AM.hasSymbolicDisplacement()) { // For X86-64, we should always use lea to materialize RIP relative // addresses. if (Subtarget->is64Bit()) Complexity = 4; else Complexity += 2; } if (AM.Disp && (AM.Base_Reg.getNode() || AM.IndexReg.getNode())) Complexity++; // If it isn't worth using an LEA, reject it. if (Complexity <= 2) return false; getAddressOperands(AM, Base, Scale, Index, Disp, Segment); return true; } /// SelectTLSADDRAddr - This is only run on TargetGlobalTLSAddress nodes. bool X86DAGToDAGISel::SelectTLSADDRAddr(SDValue N, SDValue &Base, SDValue &Scale, SDValue &Index, SDValue &Disp, SDValue &Segment) { assert(N.getOpcode() == ISD::TargetGlobalTLSAddress); const GlobalAddressSDNode *GA = cast(N); X86ISelAddressMode AM; AM.GV = GA->getGlobal(); AM.Disp += GA->getOffset(); AM.Base_Reg = CurDAG->getRegister(0, N.getValueType()); AM.SymbolFlags = GA->getTargetFlags(); if (N.getValueType() == MVT::i32) { AM.Scale = 1; AM.IndexReg = CurDAG->getRegister(X86::EBX, MVT::i32); } else { AM.IndexReg = CurDAG->getRegister(0, MVT::i64); } getAddressOperands(AM, Base, Scale, Index, Disp, Segment); return true; } bool X86DAGToDAGISel::TryFoldLoad(SDNode *P, SDValue N, SDValue &Base, SDValue &Scale, SDValue &Index, SDValue &Disp, SDValue &Segment) { if (!ISD::isNON_EXTLoad(N.getNode()) || !IsProfitableToFold(N, P, P) || !IsLegalToFold(N, P, P, OptLevel)) return false; return SelectAddr(N.getNode(), N.getOperand(1), Base, Scale, Index, Disp, Segment); } /// getGlobalBaseReg - Return an SDNode that returns the value of /// the global base register. Output instructions required to /// initialize the global base register, if necessary. /// SDNode *X86DAGToDAGISel::getGlobalBaseReg() { unsigned GlobalBaseReg = getInstrInfo()->getGlobalBaseReg(MF); return CurDAG->getRegister(GlobalBaseReg, getTargetLowering()->getPointerTy()).getNode(); } SDNode *X86DAGToDAGISel::SelectAtomic64(SDNode *Node, unsigned Opc) { SDValue Chain = Node->getOperand(0); SDValue In1 = Node->getOperand(1); SDValue In2L = Node->getOperand(2); SDValue In2H = Node->getOperand(3); SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4; if (!SelectAddr(Node, In1, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4)) return nullptr; MachineSDNode::mmo_iterator MemOp = MF->allocateMemRefsArray(1); MemOp[0] = cast(Node)->getMemOperand(); const SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, In2L, In2H, Chain}; SDNode *ResNode = CurDAG->getMachineNode(Opc, SDLoc(Node), MVT::i32, MVT::i32, MVT::Other, Ops); cast(ResNode)->setMemRefs(MemOp, MemOp + 1); return ResNode; } /// Atomic opcode table /// enum AtomicOpc { ADD, SUB, INC, DEC, OR, AND, XOR, AtomicOpcEnd }; enum AtomicSz { ConstantI8, I8, SextConstantI16, ConstantI16, I16, SextConstantI32, ConstantI32, I32, SextConstantI64, ConstantI64, I64, AtomicSzEnd }; static const uint16_t AtomicOpcTbl[AtomicOpcEnd][AtomicSzEnd] = { { X86::LOCK_ADD8mi, X86::LOCK_ADD8mr, X86::LOCK_ADD16mi8, X86::LOCK_ADD16mi, X86::LOCK_ADD16mr, X86::LOCK_ADD32mi8, X86::LOCK_ADD32mi, X86::LOCK_ADD32mr, X86::LOCK_ADD64mi8, X86::LOCK_ADD64mi32, X86::LOCK_ADD64mr, }, { X86::LOCK_SUB8mi, X86::LOCK_SUB8mr, X86::LOCK_SUB16mi8, X86::LOCK_SUB16mi, X86::LOCK_SUB16mr, X86::LOCK_SUB32mi8, X86::LOCK_SUB32mi, X86::LOCK_SUB32mr, X86::LOCK_SUB64mi8, X86::LOCK_SUB64mi32, X86::LOCK_SUB64mr, }, { 0, X86::LOCK_INC8m, 0, 0, X86::LOCK_INC16m, 0, 0, X86::LOCK_INC32m, 0, 0, X86::LOCK_INC64m, }, { 0, X86::LOCK_DEC8m, 0, 0, X86::LOCK_DEC16m, 0, 0, X86::LOCK_DEC32m, 0, 0, X86::LOCK_DEC64m, }, { X86::LOCK_OR8mi, X86::LOCK_OR8mr, X86::LOCK_OR16mi8, X86::LOCK_OR16mi, X86::LOCK_OR16mr, X86::LOCK_OR32mi8, X86::LOCK_OR32mi, X86::LOCK_OR32mr, X86::LOCK_OR64mi8, X86::LOCK_OR64mi32, X86::LOCK_OR64mr, }, { X86::LOCK_AND8mi, X86::LOCK_AND8mr, X86::LOCK_AND16mi8, X86::LOCK_AND16mi, X86::LOCK_AND16mr, X86::LOCK_AND32mi8, X86::LOCK_AND32mi, X86::LOCK_AND32mr, X86::LOCK_AND64mi8, X86::LOCK_AND64mi32, X86::LOCK_AND64mr, }, { X86::LOCK_XOR8mi, X86::LOCK_XOR8mr, X86::LOCK_XOR16mi8, X86::LOCK_XOR16mi, X86::LOCK_XOR16mr, X86::LOCK_XOR32mi8, X86::LOCK_XOR32mi, X86::LOCK_XOR32mr, X86::LOCK_XOR64mi8, X86::LOCK_XOR64mi32, X86::LOCK_XOR64mr, } }; // Return the target constant operand for atomic-load-op and do simple // translations, such as from atomic-load-add to lock-sub. The return value is // one of the following 3 cases: // + target-constant, the operand could be supported as a target constant. // + empty, the operand is not needed any more with the new op selected. // + non-empty, otherwise. static SDValue getAtomicLoadArithTargetConstant(SelectionDAG *CurDAG, SDLoc dl, enum AtomicOpc &Op, MVT NVT, SDValue Val) { if (ConstantSDNode *CN = dyn_cast(Val)) { int64_t CNVal = CN->getSExtValue(); // Quit if not 32-bit imm. if ((int32_t)CNVal != CNVal) return Val; // For atomic-load-add, we could do some optimizations. if (Op == ADD) { // Translate to INC/DEC if ADD by 1 or -1. if ((CNVal == 1) || (CNVal == -1)) { Op = (CNVal == 1) ? INC : DEC; // No more constant operand after being translated into INC/DEC. return SDValue(); } // Translate to SUB if ADD by negative value. if (CNVal < 0) { Op = SUB; CNVal = -CNVal; } } return CurDAG->getTargetConstant(CNVal, NVT); } // If the value operand is single-used, try to optimize it. if (Op == ADD && Val.hasOneUse()) { // Translate (atomic-load-add ptr (sub 0 x)) back to (lock-sub x). if (Val.getOpcode() == ISD::SUB && X86::isZeroNode(Val.getOperand(0))) { Op = SUB; return Val.getOperand(1); } // A special case for i16, which needs truncating as, in most cases, it's // promoted to i32. We will translate // (atomic-load-add (truncate (sub 0 x))) to (lock-sub (EXTRACT_SUBREG x)) if (Val.getOpcode() == ISD::TRUNCATE && NVT == MVT::i16 && Val.getOperand(0).getOpcode() == ISD::SUB && X86::isZeroNode(Val.getOperand(0).getOperand(0))) { Op = SUB; Val = Val.getOperand(0); return CurDAG->getTargetExtractSubreg(X86::sub_16bit, dl, NVT, Val.getOperand(1)); } } return Val; } SDNode *X86DAGToDAGISel::SelectAtomicLoadArith(SDNode *Node, MVT NVT) { if (Node->hasAnyUseOfValue(0)) return nullptr; SDLoc dl(Node); // Optimize common patterns for __sync_or_and_fetch and similar arith // operations where the result is not used. This allows us to use the "lock" // version of the arithmetic instruction. SDValue Chain = Node->getOperand(0); SDValue Ptr = Node->getOperand(1); SDValue Val = Node->getOperand(2); SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4; if (!SelectAddr(Node, Ptr, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4)) return nullptr; // Which index into the table. enum AtomicOpc Op; switch (Node->getOpcode()) { default: return nullptr; case ISD::ATOMIC_LOAD_OR: Op = OR; break; case ISD::ATOMIC_LOAD_AND: Op = AND; break; case ISD::ATOMIC_LOAD_XOR: Op = XOR; break; case ISD::ATOMIC_LOAD_ADD: Op = ADD; break; } Val = getAtomicLoadArithTargetConstant(CurDAG, dl, Op, NVT, Val); bool isUnOp = !Val.getNode(); bool isCN = Val.getNode() && (Val.getOpcode() == ISD::TargetConstant); unsigned Opc = 0; switch (NVT.SimpleTy) { default: return nullptr; case MVT::i8: if (isCN) Opc = AtomicOpcTbl[Op][ConstantI8]; else Opc = AtomicOpcTbl[Op][I8]; break; case MVT::i16: if (isCN) { if (immSext8(Val.getNode())) Opc = AtomicOpcTbl[Op][SextConstantI16]; else Opc = AtomicOpcTbl[Op][ConstantI16]; } else Opc = AtomicOpcTbl[Op][I16]; break; case MVT::i32: if (isCN) { if (immSext8(Val.getNode())) Opc = AtomicOpcTbl[Op][SextConstantI32]; else Opc = AtomicOpcTbl[Op][ConstantI32]; } else Opc = AtomicOpcTbl[Op][I32]; break; case MVT::i64: Opc = AtomicOpcTbl[Op][I64]; if (isCN) { if (immSext8(Val.getNode())) Opc = AtomicOpcTbl[Op][SextConstantI64]; else if (i64immSExt32(Val.getNode())) Opc = AtomicOpcTbl[Op][ConstantI64]; } break; } assert(Opc != 0 && "Invalid arith lock transform!"); SDValue Ret; SDValue Undef = SDValue(CurDAG->getMachineNode(TargetOpcode::IMPLICIT_DEF, dl, NVT), 0); MachineSDNode::mmo_iterator MemOp = MF->allocateMemRefsArray(1); MemOp[0] = cast(Node)->getMemOperand(); if (isUnOp) { SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, Chain }; Ret = SDValue(CurDAG->getMachineNode(Opc, dl, MVT::Other, Ops), 0); } else { SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, Val, Chain }; Ret = SDValue(CurDAG->getMachineNode(Opc, dl, MVT::Other, Ops), 0); } cast(Ret)->setMemRefs(MemOp, MemOp + 1); SDValue RetVals[] = { Undef, Ret }; return CurDAG->getMergeValues(RetVals, dl).getNode(); } /// HasNoSignedComparisonUses - Test whether the given X86ISD::CMP node has /// any uses which require the SF or OF bits to be accurate. static bool HasNoSignedComparisonUses(SDNode *N) { // Examine each user of the node. for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end(); UI != UE; ++UI) { // Only examine CopyToReg uses. if (UI->getOpcode() != ISD::CopyToReg) return false; // Only examine CopyToReg uses that copy to EFLAGS. if (cast(UI->getOperand(1))->getReg() != X86::EFLAGS) return false; // Examine each user of the CopyToReg use. for (SDNode::use_iterator FlagUI = UI->use_begin(), FlagUE = UI->use_end(); FlagUI != FlagUE; ++FlagUI) { // Only examine the Flag result. if (FlagUI.getUse().getResNo() != 1) continue; // Anything unusual: assume conservatively. if (!FlagUI->isMachineOpcode()) return false; // Examine the opcode of the user. switch (FlagUI->getMachineOpcode()) { // These comparisons don't treat the most significant bit specially. case X86::SETAr: case X86::SETAEr: case X86::SETBr: case X86::SETBEr: case X86::SETEr: case X86::SETNEr: case X86::SETPr: case X86::SETNPr: case X86::SETAm: case X86::SETAEm: case X86::SETBm: case X86::SETBEm: case X86::SETEm: case X86::SETNEm: case X86::SETPm: case X86::SETNPm: case X86::JA_4: case X86::JAE_4: case X86::JB_4: case X86::JBE_4: case X86::JE_4: case X86::JNE_4: case X86::JP_4: case X86::JNP_4: case X86::CMOVA16rr: case X86::CMOVA16rm: case X86::CMOVA32rr: case X86::CMOVA32rm: case X86::CMOVA64rr: case X86::CMOVA64rm: case X86::CMOVAE16rr: case X86::CMOVAE16rm: case X86::CMOVAE32rr: case X86::CMOVAE32rm: case X86::CMOVAE64rr: case X86::CMOVAE64rm: case X86::CMOVB16rr: case X86::CMOVB16rm: case X86::CMOVB32rr: case X86::CMOVB32rm: case X86::CMOVB64rr: case X86::CMOVB64rm: case X86::CMOVBE16rr: case X86::CMOVBE16rm: case X86::CMOVBE32rr: case X86::CMOVBE32rm: case X86::CMOVBE64rr: case X86::CMOVBE64rm: case X86::CMOVE16rr: case X86::CMOVE16rm: case X86::CMOVE32rr: case X86::CMOVE32rm: case X86::CMOVE64rr: case X86::CMOVE64rm: case X86::CMOVNE16rr: case X86::CMOVNE16rm: case X86::CMOVNE32rr: case X86::CMOVNE32rm: case X86::CMOVNE64rr: case X86::CMOVNE64rm: case X86::CMOVNP16rr: case X86::CMOVNP16rm: case X86::CMOVNP32rr: case X86::CMOVNP32rm: case X86::CMOVNP64rr: case X86::CMOVNP64rm: case X86::CMOVP16rr: case X86::CMOVP16rm: case X86::CMOVP32rr: case X86::CMOVP32rm: case X86::CMOVP64rr: case X86::CMOVP64rm: continue; // Anything else: assume conservatively. default: return false; } } } return true; } /// isLoadIncOrDecStore - Check whether or not the chain ending in StoreNode /// is suitable for doing the {load; increment or decrement; store} to modify /// transformation. static bool isLoadIncOrDecStore(StoreSDNode *StoreNode, unsigned Opc, SDValue StoredVal, SelectionDAG *CurDAG, LoadSDNode* &LoadNode, SDValue &InputChain) { // is the value stored the result of a DEC or INC? if (!(Opc == X86ISD::DEC || Opc == X86ISD::INC)) return false; // is the stored value result 0 of the load? if (StoredVal.getResNo() != 0) return false; // are there other uses of the loaded value than the inc or dec? 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 the size of the value one that we can handle? (i.e. 64, 32, 16, or 8) EVT LdVT = LoadNode->getMemoryVT(); if (LdVT != MVT::i64 && LdVT != MVT::i32 && LdVT != MVT::i16 && LdVT != MVT::i8) return false; // 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; for (unsigned i = 0, e = Chain.getNumOperands(); i != e; ++i) { SDValue Op = Chain.getOperand(i); if (Op == Load.getValue(1)) { ChainCheck = true; continue; } // Make sure using Op as part of the chain would not cause a cycle here. // In theory, we could check whether the chain node is a predecessor of // the load. But that can be very expensive. Instead visit the uses and // make sure they all have smaller node id than the load. int LoadId = LoadNode->getNodeId(); for (SDNode::use_iterator UI = Op.getNode()->use_begin(), UE = UI->use_end(); UI != UE; ++UI) { if (UI.getUse().getResNo() != 0) continue; if (UI->getNodeId() > LoadId) return false; } ChainOps.push_back(Op); } if (ChainCheck) // 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; } /// getFusedLdStOpcode - Get the appropriate X86 opcode for an in memory /// increment or decrement. Opc should be X86ISD::DEC or X86ISD::INC. static unsigned getFusedLdStOpcode(EVT &LdVT, unsigned Opc) { if (Opc == X86ISD::DEC) { if (LdVT == MVT::i64) return X86::DEC64m; if (LdVT == MVT::i32) return X86::DEC32m; if (LdVT == MVT::i16) return X86::DEC16m; if (LdVT == MVT::i8) return X86::DEC8m; } else { assert(Opc == X86ISD::INC && "unrecognized opcode"); if (LdVT == MVT::i64) return X86::INC64m; if (LdVT == MVT::i32) return X86::INC32m; if (LdVT == MVT::i16) return X86::INC16m; if (LdVT == MVT::i8) return X86::INC8m; } llvm_unreachable("unrecognized size for LdVT"); } /// SelectGather - Customized ISel for GATHER operations. /// SDNode *X86DAGToDAGISel::SelectGather(SDNode *Node, unsigned Opc) { // Operands of Gather: VSrc, Base, VIdx, VMask, Scale SDValue Chain = Node->getOperand(0); SDValue VSrc = Node->getOperand(2); SDValue Base = Node->getOperand(3); SDValue VIdx = Node->getOperand(4); SDValue VMask = Node->getOperand(5); ConstantSDNode *Scale = dyn_cast(Node->getOperand(6)); if (!Scale) return nullptr; SDVTList VTs = CurDAG->getVTList(VSrc.getValueType(), VSrc.getValueType(), MVT::Other); // Memory Operands: Base, Scale, Index, Disp, Segment SDValue Disp = CurDAG->getTargetConstant(0, MVT::i32); SDValue Segment = CurDAG->getRegister(0, MVT::i32); const SDValue Ops[] = { VSrc, Base, getI8Imm(Scale->getSExtValue()), VIdx, Disp, Segment, VMask, Chain}; SDNode *ResNode = CurDAG->getMachineNode(Opc, SDLoc(Node), VTs, Ops); // Node has 2 outputs: VDst and MVT::Other. // ResNode has 3 outputs: VDst, VMask_wb, and MVT::Other. // We replace VDst of Node with VDst of ResNode, and Other of Node with Other // of ResNode. ReplaceUses(SDValue(Node, 0), SDValue(ResNode, 0)); ReplaceUses(SDValue(Node, 1), SDValue(ResNode, 2)); return ResNode; } SDNode *X86DAGToDAGISel::Select(SDNode *Node) { MVT NVT = Node->getSimpleValueType(0); unsigned Opc, MOpc; unsigned Opcode = Node->getOpcode(); SDLoc dl(Node); DEBUG(dbgs() << "Selecting: "; Node->dump(CurDAG); dbgs() << '\n'); if (Node->isMachineOpcode()) { DEBUG(dbgs() << "== "; Node->dump(CurDAG); dbgs() << '\n'); Node->setNodeId(-1); return nullptr; // Already selected. } switch (Opcode) { default: break; case ISD::INTRINSIC_W_CHAIN: { unsigned IntNo = cast(Node->getOperand(1))->getZExtValue(); switch (IntNo) { default: break; case Intrinsic::x86_avx2_gather_d_pd: case Intrinsic::x86_avx2_gather_d_pd_256: case Intrinsic::x86_avx2_gather_q_pd: case Intrinsic::x86_avx2_gather_q_pd_256: case Intrinsic::x86_avx2_gather_d_ps: case Intrinsic::x86_avx2_gather_d_ps_256: case Intrinsic::x86_avx2_gather_q_ps: case Intrinsic::x86_avx2_gather_q_ps_256: case Intrinsic::x86_avx2_gather_d_q: case Intrinsic::x86_avx2_gather_d_q_256: case Intrinsic::x86_avx2_gather_q_q: case Intrinsic::x86_avx2_gather_q_q_256: case Intrinsic::x86_avx2_gather_d_d: case Intrinsic::x86_avx2_gather_d_d_256: case Intrinsic::x86_avx2_gather_q_d: case Intrinsic::x86_avx2_gather_q_d_256: { if (!Subtarget->hasAVX2()) break; unsigned Opc; switch (IntNo) { default: llvm_unreachable("Impossible intrinsic"); case Intrinsic::x86_avx2_gather_d_pd: Opc = X86::VGATHERDPDrm; break; case Intrinsic::x86_avx2_gather_d_pd_256: Opc = X86::VGATHERDPDYrm; break; case Intrinsic::x86_avx2_gather_q_pd: Opc = X86::VGATHERQPDrm; break; case Intrinsic::x86_avx2_gather_q_pd_256: Opc = X86::VGATHERQPDYrm; break; case Intrinsic::x86_avx2_gather_d_ps: Opc = X86::VGATHERDPSrm; break; case Intrinsic::x86_avx2_gather_d_ps_256: Opc = X86::VGATHERDPSYrm; break; case Intrinsic::x86_avx2_gather_q_ps: Opc = X86::VGATHERQPSrm; break; case Intrinsic::x86_avx2_gather_q_ps_256: Opc = X86::VGATHERQPSYrm; break; case Intrinsic::x86_avx2_gather_d_q: Opc = X86::VPGATHERDQrm; break; case Intrinsic::x86_avx2_gather_d_q_256: Opc = X86::VPGATHERDQYrm; break; case Intrinsic::x86_avx2_gather_q_q: Opc = X86::VPGATHERQQrm; break; case Intrinsic::x86_avx2_gather_q_q_256: Opc = X86::VPGATHERQQYrm; break; case Intrinsic::x86_avx2_gather_d_d: Opc = X86::VPGATHERDDrm; break; case Intrinsic::x86_avx2_gather_d_d_256: Opc = X86::VPGATHERDDYrm; break; case Intrinsic::x86_avx2_gather_q_d: Opc = X86::VPGATHERQDrm; break; case Intrinsic::x86_avx2_gather_q_d_256: Opc = X86::VPGATHERQDYrm; break; } SDNode *RetVal = SelectGather(Node, Opc); if (RetVal) // We already called ReplaceUses inside SelectGather. return nullptr; break; } } break; } case X86ISD::GlobalBaseReg: return getGlobalBaseReg(); case X86ISD::ATOMOR64_DAG: case X86ISD::ATOMXOR64_DAG: case X86ISD::ATOMADD64_DAG: case X86ISD::ATOMSUB64_DAG: case X86ISD::ATOMNAND64_DAG: case X86ISD::ATOMAND64_DAG: case X86ISD::ATOMMAX64_DAG: case X86ISD::ATOMMIN64_DAG: case X86ISD::ATOMUMAX64_DAG: case X86ISD::ATOMUMIN64_DAG: case X86ISD::ATOMSWAP64_DAG: { unsigned Opc; switch (Opcode) { default: llvm_unreachable("Impossible opcode"); case X86ISD::ATOMOR64_DAG: Opc = X86::ATOMOR6432; break; case X86ISD::ATOMXOR64_DAG: Opc = X86::ATOMXOR6432; break; case X86ISD::ATOMADD64_DAG: Opc = X86::ATOMADD6432; break; case X86ISD::ATOMSUB64_DAG: Opc = X86::ATOMSUB6432; break; case X86ISD::ATOMNAND64_DAG: Opc = X86::ATOMNAND6432; break; case X86ISD::ATOMAND64_DAG: Opc = X86::ATOMAND6432; break; case X86ISD::ATOMMAX64_DAG: Opc = X86::ATOMMAX6432; break; case X86ISD::ATOMMIN64_DAG: Opc = X86::ATOMMIN6432; break; case X86ISD::ATOMUMAX64_DAG: Opc = X86::ATOMUMAX6432; break; case X86ISD::ATOMUMIN64_DAG: Opc = X86::ATOMUMIN6432; break; case X86ISD::ATOMSWAP64_DAG: Opc = X86::ATOMSWAP6432; break; } SDNode *RetVal = SelectAtomic64(Node, Opc); if (RetVal) return RetVal; break; } case ISD::ATOMIC_LOAD_XOR: case ISD::ATOMIC_LOAD_AND: case ISD::ATOMIC_LOAD_OR: case ISD::ATOMIC_LOAD_ADD: { SDNode *RetVal = SelectAtomicLoadArith(Node, NVT); if (RetVal) return RetVal; break; } case ISD::AND: case ISD::OR: case ISD::XOR: { // For operations of the form (x << C1) op C2, check if we can use a smaller // encoding for C2 by transforming it into (x op (C2>>C1)) << C1. SDValue N0 = Node->getOperand(0); SDValue N1 = Node->getOperand(1); if (N0->getOpcode() != ISD::SHL || !N0->hasOneUse()) break; // i8 is unshrinkable, i16 should be promoted to i32. if (NVT != MVT::i32 && NVT != MVT::i64) break; ConstantSDNode *Cst = dyn_cast(N1); ConstantSDNode *ShlCst = dyn_cast(N0->getOperand(1)); if (!Cst || !ShlCst) break; int64_t Val = Cst->getSExtValue(); uint64_t ShlVal = ShlCst->getZExtValue(); // Make sure that we don't change the operation by removing bits. // This only matters for OR and XOR, AND is unaffected. uint64_t RemovedBitsMask = (1ULL << ShlVal) - 1; if (Opcode != ISD::AND && (Val & RemovedBitsMask) != 0) break; unsigned ShlOp, Op; MVT CstVT = NVT; // Check the minimum bitwidth for the new constant. // TODO: AND32ri is the same as AND64ri32 with zext imm. // TODO: MOV32ri+OR64r is cheaper than MOV64ri64+OR64rr // TODO: Using 16 and 8 bit operations is also possible for or32 & xor32. if (!isInt<8>(Val) && isInt<8>(Val >> ShlVal)) CstVT = MVT::i8; else if (!isInt<32>(Val) && isInt<32>(Val >> ShlVal)) CstVT = MVT::i32; // Bail if there is no smaller encoding. if (NVT == CstVT) break; switch (NVT.SimpleTy) { default: llvm_unreachable("Unsupported VT!"); case MVT::i32: assert(CstVT == MVT::i8); ShlOp = X86::SHL32ri; switch (Opcode) { default: llvm_unreachable("Impossible opcode"); case ISD::AND: Op = X86::AND32ri8; break; case ISD::OR: Op = X86::OR32ri8; break; case ISD::XOR: Op = X86::XOR32ri8; break; } break; case MVT::i64: assert(CstVT == MVT::i8 || CstVT == MVT::i32); ShlOp = X86::SHL64ri; switch (Opcode) { default: llvm_unreachable("Impossible opcode"); case ISD::AND: Op = CstVT==MVT::i8? X86::AND64ri8 : X86::AND64ri32; break; case ISD::OR: Op = CstVT==MVT::i8? X86::OR64ri8 : X86::OR64ri32; break; case ISD::XOR: Op = CstVT==MVT::i8? X86::XOR64ri8 : X86::XOR64ri32; break; } break; } // Emit the smaller op and the shift. SDValue NewCst = CurDAG->getTargetConstant(Val >> ShlVal, CstVT); SDNode *New = CurDAG->getMachineNode(Op, dl, NVT, N0->getOperand(0),NewCst); return CurDAG->SelectNodeTo(Node, ShlOp, NVT, SDValue(New, 0), getI8Imm(ShlVal)); } case X86ISD::UMUL: { SDValue N0 = Node->getOperand(0); SDValue N1 = Node->getOperand(1); unsigned LoReg; switch (NVT.SimpleTy) { default: llvm_unreachable("Unsupported VT!"); case MVT::i8: LoReg = X86::AL; Opc = X86::MUL8r; break; case MVT::i16: LoReg = X86::AX; Opc = X86::MUL16r; break; case MVT::i32: LoReg = X86::EAX; Opc = X86::MUL32r; break; case MVT::i64: LoReg = X86::RAX; Opc = X86::MUL64r; break; } SDValue InFlag = CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, LoReg, N0, SDValue()).getValue(1); SDVTList VTs = CurDAG->getVTList(NVT, NVT, MVT::i32); SDValue Ops[] = {N1, InFlag}; SDNode *CNode = CurDAG->getMachineNode(Opc, dl, VTs, Ops); ReplaceUses(SDValue(Node, 0), SDValue(CNode, 0)); ReplaceUses(SDValue(Node, 1), SDValue(CNode, 1)); ReplaceUses(SDValue(Node, 2), SDValue(CNode, 2)); return nullptr; } case ISD::SMUL_LOHI: case ISD::UMUL_LOHI: { SDValue N0 = Node->getOperand(0); SDValue N1 = Node->getOperand(1); bool isSigned = Opcode == ISD::SMUL_LOHI; bool hasBMI2 = Subtarget->hasBMI2(); if (!isSigned) { switch (NVT.SimpleTy) { default: llvm_unreachable("Unsupported VT!"); case MVT::i8: Opc = X86::MUL8r; MOpc = X86::MUL8m; break; case MVT::i16: Opc = X86::MUL16r; MOpc = X86::MUL16m; break; case MVT::i32: Opc = hasBMI2 ? X86::MULX32rr : X86::MUL32r; MOpc = hasBMI2 ? X86::MULX32rm : X86::MUL32m; break; case MVT::i64: Opc = hasBMI2 ? X86::MULX64rr : X86::MUL64r; MOpc = hasBMI2 ? X86::MULX64rm : X86::MUL64m; break; } } else { switch (NVT.SimpleTy) { default: llvm_unreachable("Unsupported VT!"); case MVT::i8: Opc = X86::IMUL8r; MOpc = X86::IMUL8m; break; case MVT::i16: Opc = X86::IMUL16r; MOpc = X86::IMUL16m; break; case MVT::i32: Opc = X86::IMUL32r; MOpc = X86::IMUL32m; break; case MVT::i64: Opc = X86::IMUL64r; MOpc = X86::IMUL64m; break; } } unsigned SrcReg, LoReg, HiReg; switch (Opc) { default: llvm_unreachable("Unknown MUL opcode!"); case X86::IMUL8r: case X86::MUL8r: SrcReg = LoReg = X86::AL; HiReg = X86::AH; break; case X86::IMUL16r: case X86::MUL16r: SrcReg = LoReg = X86::AX; HiReg = X86::DX; break; case X86::IMUL32r: case X86::MUL32r: SrcReg = LoReg = X86::EAX; HiReg = X86::EDX; break; case X86::IMUL64r: case X86::MUL64r: SrcReg = LoReg = X86::RAX; HiReg = X86::RDX; break; case X86::MULX32rr: SrcReg = X86::EDX; LoReg = HiReg = 0; break; case X86::MULX64rr: SrcReg = X86::RDX; LoReg = HiReg = 0; break; } SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4; bool foldedLoad = TryFoldLoad(Node, N1, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4); // Multiply is commmutative. if (!foldedLoad) { foldedLoad = TryFoldLoad(Node, N0, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4); if (foldedLoad) std::swap(N0, N1); } SDValue InFlag = CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, SrcReg, N0, SDValue()).getValue(1); SDValue ResHi, ResLo; if (foldedLoad) { SDValue Chain; SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, N1.getOperand(0), InFlag }; if (MOpc == X86::MULX32rm || MOpc == X86::MULX64rm) { SDVTList VTs = CurDAG->getVTList(NVT, NVT, MVT::Other, MVT::Glue); SDNode *CNode = CurDAG->getMachineNode(MOpc, dl, VTs, Ops); ResHi = SDValue(CNode, 0); ResLo = SDValue(CNode, 1); Chain = SDValue(CNode, 2); InFlag = SDValue(CNode, 3); } else { SDVTList VTs = CurDAG->getVTList(MVT::Other, MVT::Glue); SDNode *CNode = CurDAG->getMachineNode(MOpc, dl, VTs, Ops); Chain = SDValue(CNode, 0); InFlag = SDValue(CNode, 1); } // Update the chain. ReplaceUses(N1.getValue(1), Chain); } else { SDValue Ops[] = { N1, InFlag }; if (Opc == X86::MULX32rr || Opc == X86::MULX64rr) { SDVTList VTs = CurDAG->getVTList(NVT, NVT, MVT::Glue); SDNode *CNode = CurDAG->getMachineNode(Opc, dl, VTs, Ops); ResHi = SDValue(CNode, 0); ResLo = SDValue(CNode, 1); InFlag = SDValue(CNode, 2); } else { SDVTList VTs = CurDAG->getVTList(MVT::Glue); SDNode *CNode = CurDAG->getMachineNode(Opc, dl, VTs, Ops); InFlag = SDValue(CNode, 0); } } // Prevent use of AH in a REX instruction by referencing AX instead. if (HiReg == X86::AH && Subtarget->is64Bit() && !SDValue(Node, 1).use_empty()) { SDValue Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl, X86::AX, MVT::i16, InFlag); InFlag = Result.getValue(2); // Get the low part if needed. Don't use getCopyFromReg for aliasing // registers. if (!SDValue(Node, 0).use_empty()) ReplaceUses(SDValue(Node, 1), CurDAG->getTargetExtractSubreg(X86::sub_8bit, dl, MVT::i8, Result)); // Shift AX down 8 bits. Result = SDValue(CurDAG->getMachineNode(X86::SHR16ri, dl, MVT::i16, Result, CurDAG->getTargetConstant(8, MVT::i8)), 0); // Then truncate it down to i8. ReplaceUses(SDValue(Node, 1), CurDAG->getTargetExtractSubreg(X86::sub_8bit, dl, MVT::i8, Result)); } // Copy the low half of the result, if it is needed. if (!SDValue(Node, 0).use_empty()) { if (!ResLo.getNode()) { assert(LoReg && "Register for low half is not defined!"); ResLo = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl, LoReg, NVT, InFlag); InFlag = ResLo.getValue(2); } ReplaceUses(SDValue(Node, 0), ResLo); DEBUG(dbgs() << "=> "; ResLo.getNode()->dump(CurDAG); dbgs() << '\n'); } // Copy the high half of the result, if it is needed. if (!SDValue(Node, 1).use_empty()) { if (!ResHi.getNode()) { assert(HiReg && "Register for high half is not defined!"); ResHi = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl, HiReg, NVT, InFlag); InFlag = ResHi.getValue(2); } ReplaceUses(SDValue(Node, 1), ResHi); DEBUG(dbgs() << "=> "; ResHi.getNode()->dump(CurDAG); dbgs() << '\n'); } return nullptr; } case ISD::SDIVREM: case ISD::UDIVREM: { SDValue N0 = Node->getOperand(0); SDValue N1 = Node->getOperand(1); bool isSigned = Opcode == ISD::SDIVREM; if (!isSigned) { switch (NVT.SimpleTy) { default: llvm_unreachable("Unsupported VT!"); case MVT::i8: Opc = X86::DIV8r; MOpc = X86::DIV8m; break; case MVT::i16: Opc = X86::DIV16r; MOpc = X86::DIV16m; break; case MVT::i32: Opc = X86::DIV32r; MOpc = X86::DIV32m; break; case MVT::i64: Opc = X86::DIV64r; MOpc = X86::DIV64m; break; } } else { switch (NVT.SimpleTy) { default: llvm_unreachable("Unsupported VT!"); case MVT::i8: Opc = X86::IDIV8r; MOpc = X86::IDIV8m; break; case MVT::i16: Opc = X86::IDIV16r; MOpc = X86::IDIV16m; break; case MVT::i32: Opc = X86::IDIV32r; MOpc = X86::IDIV32m; break; case MVT::i64: Opc = X86::IDIV64r; MOpc = X86::IDIV64m; break; } } unsigned LoReg, HiReg, ClrReg; unsigned SExtOpcode; switch (NVT.SimpleTy) { default: llvm_unreachable("Unsupported VT!"); case MVT::i8: LoReg = X86::AL; ClrReg = HiReg = X86::AH; SExtOpcode = X86::CBW; break; case MVT::i16: LoReg = X86::AX; HiReg = X86::DX; ClrReg = X86::DX; SExtOpcode = X86::CWD; break; case MVT::i32: LoReg = X86::EAX; ClrReg = HiReg = X86::EDX; SExtOpcode = X86::CDQ; break; case MVT::i64: LoReg = X86::RAX; ClrReg = HiReg = X86::RDX; SExtOpcode = X86::CQO; break; } SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4; bool foldedLoad = TryFoldLoad(Node, N1, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4); bool signBitIsZero = CurDAG->SignBitIsZero(N0); SDValue InFlag; if (NVT == MVT::i8 && (!isSigned || signBitIsZero)) { // Special case for div8, just use a move with zero extension to AX to // clear the upper 8 bits (AH). SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, Move, Chain; if (TryFoldLoad(Node, N0, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4)) { SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, N0.getOperand(0) }; Move = SDValue(CurDAG->getMachineNode(X86::MOVZX32rm8, dl, MVT::i32, MVT::Other, Ops), 0); Chain = Move.getValue(1); ReplaceUses(N0.getValue(1), Chain); } else { Move = SDValue(CurDAG->getMachineNode(X86::MOVZX32rr8, dl, MVT::i32, N0),0); Chain = CurDAG->getEntryNode(); } Chain = CurDAG->getCopyToReg(Chain, dl, X86::EAX, Move, SDValue()); InFlag = Chain.getValue(1); } else { InFlag = CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, LoReg, N0, SDValue()).getValue(1); if (isSigned && !signBitIsZero) { // Sign extend the low part into the high part. InFlag = SDValue(CurDAG->getMachineNode(SExtOpcode, dl, MVT::Glue, InFlag),0); } else { // Zero out the high part, effectively zero extending the input. SDValue ClrNode = SDValue(CurDAG->getMachineNode(X86::MOV32r0, dl, NVT), 0); switch (NVT.SimpleTy) { case MVT::i16: ClrNode = SDValue(CurDAG->getMachineNode( TargetOpcode::EXTRACT_SUBREG, dl, MVT::i16, ClrNode, CurDAG->getTargetConstant(X86::sub_16bit, MVT::i32)), 0); break; case MVT::i32: break; case MVT::i64: ClrNode = SDValue(CurDAG->getMachineNode( TargetOpcode::SUBREG_TO_REG, dl, MVT::i64, CurDAG->getTargetConstant(0, MVT::i64), ClrNode, CurDAG->getTargetConstant(X86::sub_32bit, MVT::i32)), 0); break; default: llvm_unreachable("Unexpected division source"); } InFlag = CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, ClrReg, ClrNode, InFlag).getValue(1); } } if (foldedLoad) { SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, N1.getOperand(0), InFlag }; SDNode *CNode = CurDAG->getMachineNode(MOpc, dl, MVT::Other, MVT::Glue, Ops); InFlag = SDValue(CNode, 1); // Update the chain. ReplaceUses(N1.getValue(1), SDValue(CNode, 0)); } else { InFlag = SDValue(CurDAG->getMachineNode(Opc, dl, MVT::Glue, N1, InFlag), 0); } // Prevent use of AH in a REX instruction by referencing AX instead. // Shift it down 8 bits. // // The current assumption of the register allocator is that isel // won't generate explicit references to the GPR8_NOREX registers. If // the allocator and/or the backend get enhanced to be more robust in // that regard, this can be, and should be, removed. if (HiReg == X86::AH && Subtarget->is64Bit() && !SDValue(Node, 1).use_empty()) { SDValue Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl, X86::AX, MVT::i16, InFlag); InFlag = Result.getValue(2); // If we also need AL (the quotient), get it by extracting a subreg from // Result. The fast register allocator does not like multiple CopyFromReg // nodes using aliasing registers. if (!SDValue(Node, 0).use_empty()) ReplaceUses(SDValue(Node, 0), CurDAG->getTargetExtractSubreg(X86::sub_8bit, dl, MVT::i8, Result)); // Shift AX right by 8 bits instead of using AH. Result = SDValue(CurDAG->getMachineNode(X86::SHR16ri, dl, MVT::i16, Result, CurDAG->getTargetConstant(8, MVT::i8)), 0); ReplaceUses(SDValue(Node, 1), CurDAG->getTargetExtractSubreg(X86::sub_8bit, dl, MVT::i8, Result)); } // Copy the division (low) result, if it is needed. if (!SDValue(Node, 0).use_empty()) { SDValue Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl, LoReg, NVT, InFlag); InFlag = Result.getValue(2); ReplaceUses(SDValue(Node, 0), Result); DEBUG(dbgs() << "=> "; Result.getNode()->dump(CurDAG); dbgs() << '\n'); } // Copy the remainder (high) result, if it is needed. if (!SDValue(Node, 1).use_empty()) { SDValue Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl, HiReg, NVT, InFlag); InFlag = Result.getValue(2); ReplaceUses(SDValue(Node, 1), Result); DEBUG(dbgs() << "=> "; Result.getNode()->dump(CurDAG); dbgs() << '\n'); } return nullptr; } case X86ISD::CMP: case X86ISD::SUB: { // Sometimes a SUB is used to perform comparison. if (Opcode == X86ISD::SUB && Node->hasAnyUseOfValue(0)) // This node is not a CMP. break; SDValue N0 = Node->getOperand(0); SDValue N1 = Node->getOperand(1); // Look for (X86cmp (and $op, $imm), 0) and see if we can convert it to // use a smaller encoding. if (N0.getOpcode() == ISD::TRUNCATE && N0.hasOneUse() && HasNoSignedComparisonUses(Node)) // Look past the truncate if CMP is the only use of it. N0 = N0.getOperand(0); if ((N0.getNode()->getOpcode() == ISD::AND || (N0.getResNo() == 0 && N0.getNode()->getOpcode() == X86ISD::AND)) && N0.getNode()->hasOneUse() && N0.getValueType() != MVT::i8 && X86::isZeroNode(N1)) { ConstantSDNode *C = dyn_cast(N0.getNode()->getOperand(1)); if (!C) break; // For example, convert "testl %eax, $8" to "testb %al, $8" if ((C->getZExtValue() & ~UINT64_C(0xff)) == 0 && (!(C->getZExtValue() & 0x80) || HasNoSignedComparisonUses(Node))) { SDValue Imm = CurDAG->getTargetConstant(C->getZExtValue(), MVT::i8); SDValue Reg = N0.getNode()->getOperand(0); // On x86-32, only the ABCD registers have 8-bit subregisters. if (!Subtarget->is64Bit()) { const TargetRegisterClass *TRC; switch (N0.getSimpleValueType().SimpleTy) { case MVT::i32: TRC = &X86::GR32_ABCDRegClass; break; case MVT::i16: TRC = &X86::GR16_ABCDRegClass; break; default: llvm_unreachable("Unsupported TEST operand type!"); } SDValue RC = CurDAG->getTargetConstant(TRC->getID(), MVT::i32); Reg = SDValue(CurDAG->getMachineNode(X86::COPY_TO_REGCLASS, dl, Reg.getValueType(), Reg, RC), 0); } // Extract the l-register. SDValue Subreg = CurDAG->getTargetExtractSubreg(X86::sub_8bit, dl, MVT::i8, Reg); // Emit a testb. SDNode *NewNode = CurDAG->getMachineNode(X86::TEST8ri, dl, MVT::i32, Subreg, Imm); // Replace SUB|CMP with TEST, since SUB has two outputs while TEST has // one, do not call ReplaceAllUsesWith. ReplaceUses(SDValue(Node, (Opcode == X86ISD::SUB ? 1 : 0)), SDValue(NewNode, 0)); return nullptr; } // For example, "testl %eax, $2048" to "testb %ah, $8". if ((C->getZExtValue() & ~UINT64_C(0xff00)) == 0 && (!(C->getZExtValue() & 0x8000) || HasNoSignedComparisonUses(Node))) { // Shift the immediate right by 8 bits. SDValue ShiftedImm = CurDAG->getTargetConstant(C->getZExtValue() >> 8, MVT::i8); SDValue Reg = N0.getNode()->getOperand(0); // Put the value in an ABCD register. const TargetRegisterClass *TRC; switch (N0.getSimpleValueType().SimpleTy) { case MVT::i64: TRC = &X86::GR64_ABCDRegClass; break; case MVT::i32: TRC = &X86::GR32_ABCDRegClass; break; case MVT::i16: TRC = &X86::GR16_ABCDRegClass; break; default: llvm_unreachable("Unsupported TEST operand type!"); } SDValue RC = CurDAG->getTargetConstant(TRC->getID(), MVT::i32); Reg = SDValue(CurDAG->getMachineNode(X86::COPY_TO_REGCLASS, dl, Reg.getValueType(), Reg, RC), 0); // Extract the h-register. SDValue Subreg = CurDAG->getTargetExtractSubreg(X86::sub_8bit_hi, dl, MVT::i8, Reg); // Emit a testb. The EXTRACT_SUBREG becomes a COPY that can only // target GR8_NOREX registers, so make sure the register class is // forced. SDNode *NewNode = CurDAG->getMachineNode(X86::TEST8ri_NOREX, dl, MVT::i32, Subreg, ShiftedImm); // Replace SUB|CMP with TEST, since SUB has two outputs while TEST has // one, do not call ReplaceAllUsesWith. ReplaceUses(SDValue(Node, (Opcode == X86ISD::SUB ? 1 : 0)), SDValue(NewNode, 0)); return nullptr; } // For example, "testl %eax, $32776" to "testw %ax, $32776". if ((C->getZExtValue() & ~UINT64_C(0xffff)) == 0 && N0.getValueType() != MVT::i16 && (!(C->getZExtValue() & 0x8000) || HasNoSignedComparisonUses(Node))) { SDValue Imm = CurDAG->getTargetConstant(C->getZExtValue(), MVT::i16); SDValue Reg = N0.getNode()->getOperand(0); // Extract the 16-bit subregister. SDValue Subreg = CurDAG->getTargetExtractSubreg(X86::sub_16bit, dl, MVT::i16, Reg); // Emit a testw. SDNode *NewNode = CurDAG->getMachineNode(X86::TEST16ri, dl, MVT::i32, Subreg, Imm); // Replace SUB|CMP with TEST, since SUB has two outputs while TEST has // one, do not call ReplaceAllUsesWith. ReplaceUses(SDValue(Node, (Opcode == X86ISD::SUB ? 1 : 0)), SDValue(NewNode, 0)); return nullptr; } // For example, "testq %rax, $268468232" to "testl %eax, $268468232". if ((C->getZExtValue() & ~UINT64_C(0xffffffff)) == 0 && N0.getValueType() == MVT::i64 && (!(C->getZExtValue() & 0x80000000) || HasNoSignedComparisonUses(Node))) { SDValue Imm = CurDAG->getTargetConstant(C->getZExtValue(), MVT::i32); SDValue Reg = N0.getNode()->getOperand(0); // Extract the 32-bit subregister. SDValue Subreg = CurDAG->getTargetExtractSubreg(X86::sub_32bit, dl, MVT::i32, Reg); // Emit a testl. SDNode *NewNode = CurDAG->getMachineNode(X86::TEST32ri, dl, MVT::i32, Subreg, Imm); // Replace SUB|CMP with TEST, since SUB has two outputs while TEST has // one, do not call ReplaceAllUsesWith. ReplaceUses(SDValue(Node, (Opcode == X86ISD::SUB ? 1 : 0)), SDValue(NewNode, 0)); return nullptr; } } break; } case ISD::STORE: { // Change a chain of {load; incr or dec; store} of the same value into // a simple increment or decrement through memory of that value, if the // uses of the modified value and its address are suitable. // The DEC64m tablegen pattern is currently not able to match the case where // the EFLAGS on the original DEC are used. (This also applies to // {INC,DEC}X{64,32,16,8}.) // We'll need to improve tablegen to allow flags to be transferred from a // node in the pattern to the result node. probably with a new keyword // for example, we have this // def DEC64m : RI<0xFF, MRM1m, (outs), (ins i64mem:$dst), "dec{q}\t$dst", // [(store (add (loadi64 addr:$dst), -1), addr:$dst), // (implicit EFLAGS)]>; // but maybe need something like this // def DEC64m : RI<0xFF, MRM1m, (outs), (ins i64mem:$dst), "dec{q}\t$dst", // [(store (add (loadi64 addr:$dst), -1), addr:$dst), // (transferrable EFLAGS)]>; StoreSDNode *StoreNode = cast(Node); SDValue StoredVal = StoreNode->getOperand(1); unsigned Opc = StoredVal->getOpcode(); LoadSDNode *LoadNode = nullptr; SDValue InputChain; if (!isLoadIncOrDecStore(StoreNode, Opc, StoredVal, CurDAG, LoadNode, InputChain)) break; SDValue Base, Scale, Index, Disp, Segment; if (!SelectAddr(LoadNode, LoadNode->getBasePtr(), Base, Scale, Index, Disp, Segment)) break; MachineSDNode::mmo_iterator MemOp = MF->allocateMemRefsArray(2); MemOp[0] = StoreNode->getMemOperand(); MemOp[1] = LoadNode->getMemOperand(); const SDValue Ops[] = { Base, Scale, Index, Disp, Segment, InputChain }; EVT LdVT = LoadNode->getMemoryVT(); unsigned newOpc = getFusedLdStOpcode(LdVT, Opc); MachineSDNode *Result = CurDAG->getMachineNode(newOpc, SDLoc(Node), MVT::i32, MVT::Other, Ops); Result->setMemRefs(MemOp, MemOp + 2); ReplaceUses(SDValue(StoreNode, 0), SDValue(Result, 1)); ReplaceUses(SDValue(StoredVal.getNode(), 1), SDValue(Result, 0)); return Result; } } SDNode *ResNode = SelectCode(Node); DEBUG(dbgs() << "=> "; if (ResNode == nullptr || ResNode == Node) Node->dump(CurDAG); else ResNode->dump(CurDAG); dbgs() << '\n'); return ResNode; } bool X86DAGToDAGISel:: SelectInlineAsmMemoryOperand(const SDValue &Op, char ConstraintCode, std::vector &OutOps) { SDValue Op0, Op1, Op2, Op3, Op4; switch (ConstraintCode) { case 'o': // offsetable ?? case 'v': // not offsetable ?? default: return true; case 'm': // memory if (!SelectAddr(nullptr, Op, Op0, Op1, Op2, Op3, Op4)) return true; break; } OutOps.push_back(Op0); OutOps.push_back(Op1); OutOps.push_back(Op2); OutOps.push_back(Op3); OutOps.push_back(Op4); return false; } /// createX86ISelDag - This pass converts a legalized DAG into a /// X86-specific DAG, ready for instruction scheduling. /// FunctionPass *llvm::createX86ISelDag(X86TargetMachine &TM, CodeGenOpt::Level OptLevel) { return new X86DAGToDAGISel(TM, OptLevel); }