//===-- AArch64TargetTransformInfo.cpp - AArch64 specific TTI -------------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// #include "AArch64TargetTransformInfo.h" #include "MCTargetDesc/AArch64AddressingModes.h" #include "llvm/Analysis/TargetTransformInfo.h" #include "llvm/Analysis/LoopInfo.h" #include "llvm/CodeGen/BasicTTIImpl.h" #include "llvm/Support/Debug.h" #include "llvm/Target/CostTable.h" #include "llvm/Target/TargetLowering.h" #include <algorithm> using namespace llvm; #define DEBUG_TYPE "aarch64tti" /// \brief Calculate the cost of materializing a 64-bit value. This helper /// method might only calculate a fraction of a larger immediate. Therefore it /// is valid to return a cost of ZERO. int AArch64TTIImpl::getIntImmCost(int64_t Val) { // Check if the immediate can be encoded within an instruction. if (Val == 0 || AArch64_AM::isLogicalImmediate(Val, 64)) return 0; if (Val < 0) Val = ~Val; // Calculate how many moves we will need to materialize this constant. unsigned LZ = countLeadingZeros((uint64_t)Val); return (64 - LZ + 15) / 16; } /// \brief Calculate the cost of materializing the given constant. int AArch64TTIImpl::getIntImmCost(const APInt &Imm, Type *Ty) { assert(Ty->isIntegerTy()); unsigned BitSize = Ty->getPrimitiveSizeInBits(); if (BitSize == 0) return ~0U; // Sign-extend all constants to a multiple of 64-bit. APInt ImmVal = Imm; if (BitSize & 0x3f) ImmVal = Imm.sext((BitSize + 63) & ~0x3fU); // Split the constant into 64-bit chunks and calculate the cost for each // chunk. int Cost = 0; for (unsigned ShiftVal = 0; ShiftVal < BitSize; ShiftVal += 64) { APInt Tmp = ImmVal.ashr(ShiftVal).sextOrTrunc(64); int64_t Val = Tmp.getSExtValue(); Cost += getIntImmCost(Val); } // We need at least one instruction to materialze the constant. return std::max(1, Cost); } int AArch64TTIImpl::getIntImmCost(unsigned Opcode, unsigned Idx, const APInt &Imm, Type *Ty) { assert(Ty->isIntegerTy()); unsigned BitSize = Ty->getPrimitiveSizeInBits(); // There is no cost model for constants with a bit size of 0. Return TCC_Free // here, so that constant hoisting will ignore this constant. if (BitSize == 0) return TTI::TCC_Free; unsigned ImmIdx = ~0U; switch (Opcode) { default: return TTI::TCC_Free; case Instruction::GetElementPtr: // Always hoist the base address of a GetElementPtr. if (Idx == 0) return 2 * TTI::TCC_Basic; return TTI::TCC_Free; case Instruction::Store: ImmIdx = 0; break; case Instruction::Add: case Instruction::Sub: case Instruction::Mul: case Instruction::UDiv: case Instruction::SDiv: case Instruction::URem: case Instruction::SRem: case Instruction::And: case Instruction::Or: case Instruction::Xor: case Instruction::ICmp: ImmIdx = 1; break; // Always return TCC_Free for the shift value of a shift instruction. case Instruction::Shl: case Instruction::LShr: case Instruction::AShr: if (Idx == 1) return TTI::TCC_Free; break; case Instruction::Trunc: case Instruction::ZExt: case Instruction::SExt: case Instruction::IntToPtr: case Instruction::PtrToInt: case Instruction::BitCast: case Instruction::PHI: case Instruction::Call: case Instruction::Select: case Instruction::Ret: case Instruction::Load: break; } if (Idx == ImmIdx) { int NumConstants = (BitSize + 63) / 64; int Cost = AArch64TTIImpl::getIntImmCost(Imm, Ty); return (Cost <= NumConstants * TTI::TCC_Basic) ? static_cast<int>(TTI::TCC_Free) : Cost; } return AArch64TTIImpl::getIntImmCost(Imm, Ty); } int AArch64TTIImpl::getIntImmCost(Intrinsic::ID IID, unsigned Idx, const APInt &Imm, Type *Ty) { assert(Ty->isIntegerTy()); unsigned BitSize = Ty->getPrimitiveSizeInBits(); // There is no cost model for constants with a bit size of 0. Return TCC_Free // here, so that constant hoisting will ignore this constant. if (BitSize == 0) return TTI::TCC_Free; switch (IID) { default: return TTI::TCC_Free; case Intrinsic::sadd_with_overflow: case Intrinsic::uadd_with_overflow: case Intrinsic::ssub_with_overflow: case Intrinsic::usub_with_overflow: case Intrinsic::smul_with_overflow: case Intrinsic::umul_with_overflow: if (Idx == 1) { int NumConstants = (BitSize + 63) / 64; int Cost = AArch64TTIImpl::getIntImmCost(Imm, Ty); return (Cost <= NumConstants * TTI::TCC_Basic) ? static_cast<int>(TTI::TCC_Free) : Cost; } break; case Intrinsic::experimental_stackmap: if ((Idx < 2) || (Imm.getBitWidth() <= 64 && isInt<64>(Imm.getSExtValue()))) return TTI::TCC_Free; break; case Intrinsic::experimental_patchpoint_void: case Intrinsic::experimental_patchpoint_i64: if ((Idx < 4) || (Imm.getBitWidth() <= 64 && isInt<64>(Imm.getSExtValue()))) return TTI::TCC_Free; break; } return AArch64TTIImpl::getIntImmCost(Imm, Ty); } TargetTransformInfo::PopcntSupportKind AArch64TTIImpl::getPopcntSupport(unsigned TyWidth) { assert(isPowerOf2_32(TyWidth) && "Ty width must be power of 2"); if (TyWidth == 32 || TyWidth == 64) return TTI::PSK_FastHardware; // TODO: AArch64TargetLowering::LowerCTPOP() supports 128bit popcount. return TTI::PSK_Software; } int AArch64TTIImpl::getCastInstrCost(unsigned Opcode, Type *Dst, Type *Src) { int ISD = TLI->InstructionOpcodeToISD(Opcode); assert(ISD && "Invalid opcode"); EVT SrcTy = TLI->getValueType(DL, Src); EVT DstTy = TLI->getValueType(DL, Dst); if (!SrcTy.isSimple() || !DstTy.isSimple()) return BaseT::getCastInstrCost(Opcode, Dst, Src); static const TypeConversionCostTblEntry ConversionTbl[] = { { ISD::TRUNCATE, MVT::v4i16, MVT::v4i32, 1 }, { ISD::TRUNCATE, MVT::v4i32, MVT::v4i64, 0 }, { ISD::TRUNCATE, MVT::v8i8, MVT::v8i32, 3 }, { ISD::TRUNCATE, MVT::v16i8, MVT::v16i32, 6 }, // The number of shll instructions for the extension. { ISD::SIGN_EXTEND, MVT::v4i64, MVT::v4i16, 3 }, { ISD::ZERO_EXTEND, MVT::v4i64, MVT::v4i16, 3 }, { ISD::SIGN_EXTEND, MVT::v4i64, MVT::v4i32, 2 }, { ISD::ZERO_EXTEND, MVT::v4i64, MVT::v4i32, 2 }, { ISD::SIGN_EXTEND, MVT::v8i32, MVT::v8i8, 3 }, { ISD::ZERO_EXTEND, MVT::v8i32, MVT::v8i8, 3 }, { ISD::SIGN_EXTEND, MVT::v8i32, MVT::v8i16, 2 }, { ISD::ZERO_EXTEND, MVT::v8i32, MVT::v8i16, 2 }, { ISD::SIGN_EXTEND, MVT::v8i64, MVT::v8i8, 7 }, { ISD::ZERO_EXTEND, MVT::v8i64, MVT::v8i8, 7 }, { ISD::SIGN_EXTEND, MVT::v8i64, MVT::v8i16, 6 }, { ISD::ZERO_EXTEND, MVT::v8i64, MVT::v8i16, 6 }, { ISD::SIGN_EXTEND, MVT::v16i16, MVT::v16i8, 2 }, { ISD::ZERO_EXTEND, MVT::v16i16, MVT::v16i8, 2 }, { ISD::SIGN_EXTEND, MVT::v16i32, MVT::v16i8, 6 }, { ISD::ZERO_EXTEND, MVT::v16i32, MVT::v16i8, 6 }, // LowerVectorINT_TO_FP: { ISD::SINT_TO_FP, MVT::v2f32, MVT::v2i32, 1 }, { ISD::SINT_TO_FP, MVT::v4f32, MVT::v4i32, 1 }, { ISD::SINT_TO_FP, MVT::v2f64, MVT::v2i64, 1 }, { ISD::UINT_TO_FP, MVT::v2f32, MVT::v2i32, 1 }, { ISD::UINT_TO_FP, MVT::v4f32, MVT::v4i32, 1 }, { ISD::UINT_TO_FP, MVT::v2f64, MVT::v2i64, 1 }, // Complex: to v2f32 { ISD::SINT_TO_FP, MVT::v2f32, MVT::v2i8, 3 }, { ISD::SINT_TO_FP, MVT::v2f32, MVT::v2i16, 3 }, { ISD::SINT_TO_FP, MVT::v2f32, MVT::v2i64, 2 }, { ISD::UINT_TO_FP, MVT::v2f32, MVT::v2i8, 3 }, { ISD::UINT_TO_FP, MVT::v2f32, MVT::v2i16, 3 }, { ISD::UINT_TO_FP, MVT::v2f32, MVT::v2i64, 2 }, // Complex: to v4f32 { ISD::SINT_TO_FP, MVT::v4f32, MVT::v4i8, 4 }, { ISD::SINT_TO_FP, MVT::v4f32, MVT::v4i16, 2 }, { ISD::UINT_TO_FP, MVT::v4f32, MVT::v4i8, 3 }, { ISD::UINT_TO_FP, MVT::v4f32, MVT::v4i16, 2 }, // Complex: to v8f32 { ISD::SINT_TO_FP, MVT::v8f32, MVT::v8i8, 10 }, { ISD::SINT_TO_FP, MVT::v8f32, MVT::v8i16, 4 }, { ISD::UINT_TO_FP, MVT::v8f32, MVT::v8i8, 10 }, { ISD::UINT_TO_FP, MVT::v8f32, MVT::v8i16, 4 }, // Complex: to v16f32 { ISD::SINT_TO_FP, MVT::v16f32, MVT::v16i8, 21 }, { ISD::UINT_TO_FP, MVT::v16f32, MVT::v16i8, 21 }, // Complex: to v2f64 { ISD::SINT_TO_FP, MVT::v2f64, MVT::v2i8, 4 }, { ISD::SINT_TO_FP, MVT::v2f64, MVT::v2i16, 4 }, { ISD::SINT_TO_FP, MVT::v2f64, MVT::v2i32, 2 }, { ISD::UINT_TO_FP, MVT::v2f64, MVT::v2i8, 4 }, { ISD::UINT_TO_FP, MVT::v2f64, MVT::v2i16, 4 }, { ISD::UINT_TO_FP, MVT::v2f64, MVT::v2i32, 2 }, // LowerVectorFP_TO_INT { ISD::FP_TO_SINT, MVT::v2i32, MVT::v2f32, 1 }, { ISD::FP_TO_SINT, MVT::v4i32, MVT::v4f32, 1 }, { ISD::FP_TO_SINT, MVT::v2i64, MVT::v2f64, 1 }, { ISD::FP_TO_UINT, MVT::v2i32, MVT::v2f32, 1 }, { ISD::FP_TO_UINT, MVT::v4i32, MVT::v4f32, 1 }, { ISD::FP_TO_UINT, MVT::v2i64, MVT::v2f64, 1 }, // Complex, from v2f32: legal type is v2i32 (no cost) or v2i64 (1 ext). { ISD::FP_TO_SINT, MVT::v2i64, MVT::v2f32, 2 }, { ISD::FP_TO_SINT, MVT::v2i16, MVT::v2f32, 1 }, { ISD::FP_TO_SINT, MVT::v2i8, MVT::v2f32, 1 }, { ISD::FP_TO_UINT, MVT::v2i64, MVT::v2f32, 2 }, { ISD::FP_TO_UINT, MVT::v2i16, MVT::v2f32, 1 }, { ISD::FP_TO_UINT, MVT::v2i8, MVT::v2f32, 1 }, // Complex, from v4f32: legal type is v4i16, 1 narrowing => ~2 { ISD::FP_TO_SINT, MVT::v4i16, MVT::v4f32, 2 }, { ISD::FP_TO_SINT, MVT::v4i8, MVT::v4f32, 2 }, { ISD::FP_TO_UINT, MVT::v4i16, MVT::v4f32, 2 }, { ISD::FP_TO_UINT, MVT::v4i8, MVT::v4f32, 2 }, // Complex, from v2f64: legal type is v2i32, 1 narrowing => ~2. { ISD::FP_TO_SINT, MVT::v2i32, MVT::v2f64, 2 }, { ISD::FP_TO_SINT, MVT::v2i16, MVT::v2f64, 2 }, { ISD::FP_TO_SINT, MVT::v2i8, MVT::v2f64, 2 }, { ISD::FP_TO_UINT, MVT::v2i32, MVT::v2f64, 2 }, { ISD::FP_TO_UINT, MVT::v2i16, MVT::v2f64, 2 }, { ISD::FP_TO_UINT, MVT::v2i8, MVT::v2f64, 2 }, }; if (const auto *Entry = ConvertCostTableLookup(ConversionTbl, ISD, DstTy.getSimpleVT(), SrcTy.getSimpleVT())) return Entry->Cost; return BaseT::getCastInstrCost(Opcode, Dst, Src); } int AArch64TTIImpl::getVectorInstrCost(unsigned Opcode, Type *Val, unsigned Index) { assert(Val->isVectorTy() && "This must be a vector type"); if (Index != -1U) { // Legalize the type. std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, Val); // This type is legalized to a scalar type. if (!LT.second.isVector()) return 0; // The type may be split. Normalize the index to the new type. unsigned Width = LT.second.getVectorNumElements(); Index = Index % Width; // The element at index zero is already inside the vector. if (Index == 0) return 0; } // All other insert/extracts cost this much. return 3; } int AArch64TTIImpl::getArithmeticInstrCost( unsigned Opcode, Type *Ty, TTI::OperandValueKind Opd1Info, TTI::OperandValueKind Opd2Info, TTI::OperandValueProperties Opd1PropInfo, TTI::OperandValueProperties Opd2PropInfo) { // Legalize the type. std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, Ty); int ISD = TLI->InstructionOpcodeToISD(Opcode); if (ISD == ISD::SDIV && Opd2Info == TargetTransformInfo::OK_UniformConstantValue && Opd2PropInfo == TargetTransformInfo::OP_PowerOf2) { // On AArch64, scalar signed division by constants power-of-two are // normally expanded to the sequence ADD + CMP + SELECT + SRA. // The OperandValue properties many not be same as that of previous // operation; conservatively assume OP_None. int Cost = getArithmeticInstrCost(Instruction::Add, Ty, Opd1Info, Opd2Info, TargetTransformInfo::OP_None, TargetTransformInfo::OP_None); Cost += getArithmeticInstrCost(Instruction::Sub, Ty, Opd1Info, Opd2Info, TargetTransformInfo::OP_None, TargetTransformInfo::OP_None); Cost += getArithmeticInstrCost(Instruction::Select, Ty, Opd1Info, Opd2Info, TargetTransformInfo::OP_None, TargetTransformInfo::OP_None); Cost += getArithmeticInstrCost(Instruction::AShr, Ty, Opd1Info, Opd2Info, TargetTransformInfo::OP_None, TargetTransformInfo::OP_None); return Cost; } switch (ISD) { default: return BaseT::getArithmeticInstrCost(Opcode, Ty, Opd1Info, Opd2Info, Opd1PropInfo, Opd2PropInfo); case ISD::ADD: case ISD::MUL: case ISD::XOR: case ISD::OR: case ISD::AND: // These nodes are marked as 'custom' for combining purposes only. // We know that they are legal. See LowerAdd in ISelLowering. return 1 * LT.first; } } int AArch64TTIImpl::getAddressComputationCost(Type *Ty, bool IsComplex) { // Address computations in vectorized code with non-consecutive addresses will // likely result in more instructions compared to scalar code where the // computation can more often be merged into the index mode. The resulting // extra micro-ops can significantly decrease throughput. unsigned NumVectorInstToHideOverhead = 10; if (Ty->isVectorTy() && IsComplex) return NumVectorInstToHideOverhead; // In many cases the address computation is not merged into the instruction // addressing mode. return 1; } int AArch64TTIImpl::getCmpSelInstrCost(unsigned Opcode, Type *ValTy, Type *CondTy) { int ISD = TLI->InstructionOpcodeToISD(Opcode); // We don't lower some vector selects well that are wider than the register // width. if (ValTy->isVectorTy() && ISD == ISD::SELECT) { // We would need this many instructions to hide the scalarization happening. const int AmortizationCost = 20; static const TypeConversionCostTblEntry VectorSelectTbl[] = { { ISD::SELECT, MVT::v16i1, MVT::v16i16, 16 }, { ISD::SELECT, MVT::v8i1, MVT::v8i32, 8 }, { ISD::SELECT, MVT::v16i1, MVT::v16i32, 16 }, { ISD::SELECT, MVT::v4i1, MVT::v4i64, 4 * AmortizationCost }, { ISD::SELECT, MVT::v8i1, MVT::v8i64, 8 * AmortizationCost }, { ISD::SELECT, MVT::v16i1, MVT::v16i64, 16 * AmortizationCost } }; EVT SelCondTy = TLI->getValueType(DL, CondTy); EVT SelValTy = TLI->getValueType(DL, ValTy); if (SelCondTy.isSimple() && SelValTy.isSimple()) { if (const auto *Entry = ConvertCostTableLookup(VectorSelectTbl, ISD, SelCondTy.getSimpleVT(), SelValTy.getSimpleVT())) return Entry->Cost; } } return BaseT::getCmpSelInstrCost(Opcode, ValTy, CondTy); } int AArch64TTIImpl::getMemoryOpCost(unsigned Opcode, Type *Src, unsigned Alignment, unsigned AddressSpace) { std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, Src); if (Opcode == Instruction::Store && Src->isVectorTy() && Alignment != 16 && Src->getVectorElementType()->isIntegerTy(64)) { // Unaligned stores are extremely inefficient. We don't split // unaligned v2i64 stores because the negative impact that has shown in // practice on inlined memcpy code. // We make v2i64 stores expensive so that we will only vectorize if there // are 6 other instructions getting vectorized. int AmortizationCost = 6; return LT.first * 2 * AmortizationCost; } if (Src->isVectorTy() && Src->getVectorElementType()->isIntegerTy(8) && Src->getVectorNumElements() < 8) { // We scalarize the loads/stores because there is not v.4b register and we // have to promote the elements to v.4h. unsigned NumVecElts = Src->getVectorNumElements(); unsigned NumVectorizableInstsToAmortize = NumVecElts * 2; // We generate 2 instructions per vector element. return NumVectorizableInstsToAmortize * NumVecElts * 2; } return LT.first; } int AArch64TTIImpl::getInterleavedMemoryOpCost(unsigned Opcode, Type *VecTy, unsigned Factor, ArrayRef<unsigned> Indices, unsigned Alignment, unsigned AddressSpace) { assert(Factor >= 2 && "Invalid interleave factor"); assert(isa<VectorType>(VecTy) && "Expect a vector type"); if (Factor <= TLI->getMaxSupportedInterleaveFactor()) { unsigned NumElts = VecTy->getVectorNumElements(); Type *SubVecTy = VectorType::get(VecTy->getScalarType(), NumElts / Factor); unsigned SubVecSize = DL.getTypeSizeInBits(SubVecTy); // ldN/stN only support legal vector types of size 64 or 128 in bits. if (NumElts % Factor == 0 && (SubVecSize == 64 || SubVecSize == 128)) return Factor; } return BaseT::getInterleavedMemoryOpCost(Opcode, VecTy, Factor, Indices, Alignment, AddressSpace); } int AArch64TTIImpl::getCostOfKeepingLiveOverCall(ArrayRef<Type *> Tys) { int Cost = 0; for (auto *I : Tys) { if (!I->isVectorTy()) continue; if (I->getScalarSizeInBits() * I->getVectorNumElements() == 128) Cost += getMemoryOpCost(Instruction::Store, I, 128, 0) + getMemoryOpCost(Instruction::Load, I, 128, 0); } return Cost; } unsigned AArch64TTIImpl::getMaxInterleaveFactor(unsigned VF) { if (ST->isCortexA57()) return 4; return 2; } void AArch64TTIImpl::getUnrollingPreferences(Loop *L, TTI::UnrollingPreferences &UP) { // Enable partial unrolling and runtime unrolling. BaseT::getUnrollingPreferences(L, UP); // For inner loop, it is more likely to be a hot one, and the runtime check // can be promoted out from LICM pass, so the overhead is less, let's try // a larger threshold to unroll more loops. if (L->getLoopDepth() > 1) UP.PartialThreshold *= 2; // Disable partial & runtime unrolling on -Os. UP.PartialOptSizeThreshold = 0; } Value *AArch64TTIImpl::getOrCreateResultFromMemIntrinsic(IntrinsicInst *Inst, Type *ExpectedType) { switch (Inst->getIntrinsicID()) { default: return nullptr; case Intrinsic::aarch64_neon_st2: case Intrinsic::aarch64_neon_st3: case Intrinsic::aarch64_neon_st4: { // Create a struct type StructType *ST = dyn_cast<StructType>(ExpectedType); if (!ST) return nullptr; unsigned NumElts = Inst->getNumArgOperands() - 1; if (ST->getNumElements() != NumElts) return nullptr; for (unsigned i = 0, e = NumElts; i != e; ++i) { if (Inst->getArgOperand(i)->getType() != ST->getElementType(i)) return nullptr; } Value *Res = UndefValue::get(ExpectedType); IRBuilder<> Builder(Inst); for (unsigned i = 0, e = NumElts; i != e; ++i) { Value *L = Inst->getArgOperand(i); Res = Builder.CreateInsertValue(Res, L, i); } return Res; } case Intrinsic::aarch64_neon_ld2: case Intrinsic::aarch64_neon_ld3: case Intrinsic::aarch64_neon_ld4: if (Inst->getType() == ExpectedType) return Inst; return nullptr; } } bool AArch64TTIImpl::getTgtMemIntrinsic(IntrinsicInst *Inst, MemIntrinsicInfo &Info) { switch (Inst->getIntrinsicID()) { default: break; case Intrinsic::aarch64_neon_ld2: case Intrinsic::aarch64_neon_ld3: case Intrinsic::aarch64_neon_ld4: Info.ReadMem = true; Info.WriteMem = false; Info.IsSimple = true; Info.NumMemRefs = 1; Info.PtrVal = Inst->getArgOperand(0); break; case Intrinsic::aarch64_neon_st2: case Intrinsic::aarch64_neon_st3: case Intrinsic::aarch64_neon_st4: Info.ReadMem = false; Info.WriteMem = true; Info.IsSimple = true; Info.NumMemRefs = 1; Info.PtrVal = Inst->getArgOperand(Inst->getNumArgOperands() - 1); break; } switch (Inst->getIntrinsicID()) { default: return false; case Intrinsic::aarch64_neon_ld2: case Intrinsic::aarch64_neon_st2: Info.MatchingId = VECTOR_LDST_TWO_ELEMENTS; break; case Intrinsic::aarch64_neon_ld3: case Intrinsic::aarch64_neon_st3: Info.MatchingId = VECTOR_LDST_THREE_ELEMENTS; break; case Intrinsic::aarch64_neon_ld4: case Intrinsic::aarch64_neon_st4: Info.MatchingId = VECTOR_LDST_FOUR_ELEMENTS; break; } return true; }