//===- ARMTargetTransformInfo.cpp - ARM specific TTI ----------------------===// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // //===----------------------------------------------------------------------===// #include "ARMTargetTransformInfo.h" #include "ARMSubtarget.h" #include "MCTargetDesc/ARMAddressingModes.h" #include "llvm/ADT/APInt.h" #include "llvm/ADT/SmallVector.h" #include "llvm/Analysis/LoopInfo.h" #include "llvm/CodeGen/CostTable.h" #include "llvm/CodeGen/ISDOpcodes.h" #include "llvm/CodeGen/ValueTypes.h" #include "llvm/CodeGenTypes/MachineValueType.h" #include "llvm/IR/BasicBlock.h" #include "llvm/IR/DataLayout.h" #include "llvm/IR/DerivedTypes.h" #include "llvm/IR/Instruction.h" #include "llvm/IR/Instructions.h" #include "llvm/IR/IntrinsicInst.h" #include "llvm/IR/Intrinsics.h" #include "llvm/IR/IntrinsicsARM.h" #include "llvm/IR/PatternMatch.h" #include "llvm/IR/Type.h" #include "llvm/Support/Casting.h" #include "llvm/Support/KnownBits.h" #include "llvm/Target/TargetMachine.h" #include "llvm/TargetParser/SubtargetFeature.h" #include "llvm/Transforms/InstCombine/InstCombiner.h" #include "llvm/Transforms/Utils/Local.h" #include "llvm/Transforms/Utils/LoopUtils.h" #include "llvm/Transforms/Vectorize/LoopVectorizationLegality.h" #include #include #include #include #include using namespace llvm; #define DEBUG_TYPE "armtti" static cl::opt EnableMaskedLoadStores( "enable-arm-maskedldst", cl::Hidden, cl::init(true), cl::desc("Enable the generation of masked loads and stores")); static cl::opt DisableLowOverheadLoops( "disable-arm-loloops", cl::Hidden, cl::init(false), cl::desc("Disable the generation of low-overhead loops")); static cl::opt AllowWLSLoops("allow-arm-wlsloops", cl::Hidden, cl::init(true), cl::desc("Enable the generation of WLS loops")); extern cl::opt EnableTailPredication; extern cl::opt EnableMaskedGatherScatters; extern cl::opt MVEMaxSupportedInterleaveFactor; /// Convert a vector load intrinsic into a simple llvm load instruction. /// This is beneficial when the underlying object being addressed comes /// from a constant, since we get constant-folding for free. static Value *simplifyNeonVld1(const IntrinsicInst &II, unsigned MemAlign, InstCombiner::BuilderTy &Builder) { auto *IntrAlign = dyn_cast(II.getArgOperand(1)); if (!IntrAlign) return nullptr; unsigned Alignment = IntrAlign->getLimitedValue() < MemAlign ? MemAlign : IntrAlign->getLimitedValue(); if (!isPowerOf2_32(Alignment)) return nullptr; auto *BCastInst = Builder.CreateBitCast(II.getArgOperand(0), PointerType::get(II.getType(), 0)); return Builder.CreateAlignedLoad(II.getType(), BCastInst, Align(Alignment)); } bool ARMTTIImpl::areInlineCompatible(const Function *Caller, const Function *Callee) const { const TargetMachine &TM = getTLI()->getTargetMachine(); const FeatureBitset &CallerBits = TM.getSubtargetImpl(*Caller)->getFeatureBits(); const FeatureBitset &CalleeBits = TM.getSubtargetImpl(*Callee)->getFeatureBits(); // To inline a callee, all features not in the allowed list must match exactly. bool MatchExact = (CallerBits & ~InlineFeaturesAllowed) == (CalleeBits & ~InlineFeaturesAllowed); // For features in the allowed list, the callee's features must be a subset of // the callers'. bool MatchSubset = ((CallerBits & CalleeBits) & InlineFeaturesAllowed) == (CalleeBits & InlineFeaturesAllowed); return MatchExact && MatchSubset; } TTI::AddressingModeKind ARMTTIImpl::getPreferredAddressingMode(const Loop *L, ScalarEvolution *SE) const { if (ST->hasMVEIntegerOps()) return TTI::AMK_PostIndexed; if (L->getHeader()->getParent()->hasOptSize()) return TTI::AMK_None; if (ST->isMClass() && ST->isThumb2() && L->getNumBlocks() == 1) return TTI::AMK_PreIndexed; return TTI::AMK_None; } std::optional ARMTTIImpl::instCombineIntrinsic(InstCombiner &IC, IntrinsicInst &II) const { using namespace PatternMatch; Intrinsic::ID IID = II.getIntrinsicID(); switch (IID) { default: break; case Intrinsic::arm_neon_vld1: { Align MemAlign = getKnownAlignment(II.getArgOperand(0), IC.getDataLayout(), &II, &IC.getAssumptionCache(), &IC.getDominatorTree()); if (Value *V = simplifyNeonVld1(II, MemAlign.value(), IC.Builder)) { return IC.replaceInstUsesWith(II, V); } break; } case Intrinsic::arm_neon_vld2: case Intrinsic::arm_neon_vld3: case Intrinsic::arm_neon_vld4: case Intrinsic::arm_neon_vld2lane: case Intrinsic::arm_neon_vld3lane: case Intrinsic::arm_neon_vld4lane: case Intrinsic::arm_neon_vst1: case Intrinsic::arm_neon_vst2: case Intrinsic::arm_neon_vst3: case Intrinsic::arm_neon_vst4: case Intrinsic::arm_neon_vst2lane: case Intrinsic::arm_neon_vst3lane: case Intrinsic::arm_neon_vst4lane: { Align MemAlign = getKnownAlignment(II.getArgOperand(0), IC.getDataLayout(), &II, &IC.getAssumptionCache(), &IC.getDominatorTree()); unsigned AlignArg = II.arg_size() - 1; Value *AlignArgOp = II.getArgOperand(AlignArg); MaybeAlign Align = cast(AlignArgOp)->getMaybeAlignValue(); if (Align && *Align < MemAlign) { return IC.replaceOperand( II, AlignArg, ConstantInt::get(Type::getInt32Ty(II.getContext()), MemAlign.value(), false)); } break; } case Intrinsic::arm_mve_pred_i2v: { Value *Arg = II.getArgOperand(0); Value *ArgArg; if (match(Arg, PatternMatch::m_Intrinsic( PatternMatch::m_Value(ArgArg))) && II.getType() == ArgArg->getType()) { return IC.replaceInstUsesWith(II, ArgArg); } Constant *XorMask; if (match(Arg, m_Xor(PatternMatch::m_Intrinsic( PatternMatch::m_Value(ArgArg)), PatternMatch::m_Constant(XorMask))) && II.getType() == ArgArg->getType()) { if (auto *CI = dyn_cast(XorMask)) { if (CI->getValue().trunc(16).isAllOnes()) { auto TrueVector = IC.Builder.CreateVectorSplat( cast(II.getType())->getNumElements(), IC.Builder.getTrue()); return BinaryOperator::Create(Instruction::Xor, ArgArg, TrueVector); } } } KnownBits ScalarKnown(32); if (IC.SimplifyDemandedBits(&II, 0, APInt::getLowBitsSet(32, 16), ScalarKnown)) { return &II; } break; } case Intrinsic::arm_mve_pred_v2i: { Value *Arg = II.getArgOperand(0); Value *ArgArg; if (match(Arg, PatternMatch::m_Intrinsic( PatternMatch::m_Value(ArgArg)))) { return IC.replaceInstUsesWith(II, ArgArg); } if (II.getMetadata(LLVMContext::MD_range)) break; ConstantRange Range(APInt(32, 0), APInt(32, 0x10000)); if (auto CurrentRange = II.getRange()) { Range = Range.intersectWith(*CurrentRange); if (Range == CurrentRange) break; } II.addRangeRetAttr(Range); II.addRetAttr(Attribute::NoUndef); return &II; } case Intrinsic::arm_mve_vadc: case Intrinsic::arm_mve_vadc_predicated: { unsigned CarryOp = (II.getIntrinsicID() == Intrinsic::arm_mve_vadc_predicated) ? 3 : 2; assert(II.getArgOperand(CarryOp)->getType()->getScalarSizeInBits() == 32 && "Bad type for intrinsic!"); KnownBits CarryKnown(32); if (IC.SimplifyDemandedBits(&II, CarryOp, APInt::getOneBitSet(32, 29), CarryKnown)) { return &II; } break; } case Intrinsic::arm_mve_vmldava: { Instruction *I = cast(&II); if (I->hasOneUse()) { auto *User = cast(*I->user_begin()); Value *OpZ; if (match(User, m_c_Add(m_Specific(I), m_Value(OpZ))) && match(I->getOperand(3), m_Zero())) { Value *OpX = I->getOperand(4); Value *OpY = I->getOperand(5); Type *OpTy = OpX->getType(); IC.Builder.SetInsertPoint(User); Value *V = IC.Builder.CreateIntrinsic(Intrinsic::arm_mve_vmldava, {OpTy}, {I->getOperand(0), I->getOperand(1), I->getOperand(2), OpZ, OpX, OpY}); IC.replaceInstUsesWith(*User, V); return IC.eraseInstFromFunction(*User); } } return std::nullopt; } } return std::nullopt; } std::optional ARMTTIImpl::simplifyDemandedVectorEltsIntrinsic( InstCombiner &IC, IntrinsicInst &II, APInt OrigDemandedElts, APInt &UndefElts, APInt &UndefElts2, APInt &UndefElts3, std::function SimplifyAndSetOp) const { // Compute the demanded bits for a narrowing MVE intrinsic. The TopOpc is the // opcode specifying a Top/Bottom instruction, which can change between // instructions. auto SimplifyNarrowInstrTopBottom =[&](unsigned TopOpc) { unsigned NumElts = cast(II.getType())->getNumElements(); unsigned IsTop = cast(II.getOperand(TopOpc))->getZExtValue(); // The only odd/even lanes of operand 0 will only be demanded depending // on whether this is a top/bottom instruction. APInt DemandedElts = APInt::getSplat(NumElts, IsTop ? APInt::getLowBitsSet(2, 1) : APInt::getHighBitsSet(2, 1)); SimplifyAndSetOp(&II, 0, OrigDemandedElts & DemandedElts, UndefElts); // The other lanes will be defined from the inserted elements. UndefElts &= APInt::getSplat(NumElts, IsTop ? APInt::getLowBitsSet(2, 1) : APInt::getHighBitsSet(2, 1)); return std::nullopt; }; switch (II.getIntrinsicID()) { default: break; case Intrinsic::arm_mve_vcvt_narrow: SimplifyNarrowInstrTopBottom(2); break; case Intrinsic::arm_mve_vqmovn: SimplifyNarrowInstrTopBottom(4); break; case Intrinsic::arm_mve_vshrn: SimplifyNarrowInstrTopBottom(7); break; } return std::nullopt; } InstructionCost ARMTTIImpl::getIntImmCost(const APInt &Imm, Type *Ty, TTI::TargetCostKind CostKind) { assert(Ty->isIntegerTy()); unsigned Bits = Ty->getPrimitiveSizeInBits(); if (Bits == 0 || Imm.getActiveBits() >= 64) return 4; int64_t SImmVal = Imm.getSExtValue(); uint64_t ZImmVal = Imm.getZExtValue(); if (!ST->isThumb()) { if ((SImmVal >= 0 && SImmVal < 65536) || (ARM_AM::getSOImmVal(ZImmVal) != -1) || (ARM_AM::getSOImmVal(~ZImmVal) != -1)) return 1; return ST->hasV6T2Ops() ? 2 : 3; } if (ST->isThumb2()) { if ((SImmVal >= 0 && SImmVal < 65536) || (ARM_AM::getT2SOImmVal(ZImmVal) != -1) || (ARM_AM::getT2SOImmVal(~ZImmVal) != -1)) return 1; return ST->hasV6T2Ops() ? 2 : 3; } // Thumb1, any i8 imm cost 1. if (Bits == 8 || (SImmVal >= 0 && SImmVal < 256)) return 1; if ((~SImmVal < 256) || ARM_AM::isThumbImmShiftedVal(ZImmVal)) return 2; // Load from constantpool. return 3; } // Constants smaller than 256 fit in the immediate field of // Thumb1 instructions so we return a zero cost and 1 otherwise. InstructionCost ARMTTIImpl::getIntImmCodeSizeCost(unsigned Opcode, unsigned Idx, const APInt &Imm, Type *Ty) { if (Imm.isNonNegative() && Imm.getLimitedValue() < 256) return 0; return 1; } // Checks whether Inst is part of a min(max()) or max(min()) pattern // that will match to an SSAT instruction. Returns the instruction being // saturated, or null if no saturation pattern was found. static Value *isSSATMinMaxPattern(Instruction *Inst, const APInt &Imm) { Value *LHS, *RHS; ConstantInt *C; SelectPatternFlavor InstSPF = matchSelectPattern(Inst, LHS, RHS).Flavor; if (InstSPF == SPF_SMAX && PatternMatch::match(RHS, PatternMatch::m_ConstantInt(C)) && C->getValue() == Imm && Imm.isNegative() && Imm.isNegatedPowerOf2()) { auto isSSatMin = [&](Value *MinInst) { if (isa(MinInst)) { Value *MinLHS, *MinRHS; ConstantInt *MinC; SelectPatternFlavor MinSPF = matchSelectPattern(MinInst, MinLHS, MinRHS).Flavor; if (MinSPF == SPF_SMIN && PatternMatch::match(MinRHS, PatternMatch::m_ConstantInt(MinC)) && MinC->getValue() == ((-Imm) - 1)) return true; } return false; }; if (isSSatMin(Inst->getOperand(1))) return cast(Inst->getOperand(1))->getOperand(1); if (Inst->hasNUses(2) && (isSSatMin(*Inst->user_begin()) || isSSatMin(*(++Inst->user_begin())))) return Inst->getOperand(1); } return nullptr; } // Look for a FP Saturation pattern, where the instruction can be simplified to // a fptosi.sat. max(min(fptosi)). The constant in this case is always free. static bool isFPSatMinMaxPattern(Instruction *Inst, const APInt &Imm) { if (Imm.getBitWidth() != 64 || Imm != APInt::getHighBitsSet(64, 33)) // -2147483648 return false; Value *FP = isSSATMinMaxPattern(Inst, Imm); if (!FP && isa(Inst) && Inst->hasOneUse()) FP = isSSATMinMaxPattern(cast(*Inst->user_begin()), Imm); if (!FP) return false; return isa(FP); } InstructionCost ARMTTIImpl::getIntImmCostInst(unsigned Opcode, unsigned Idx, const APInt &Imm, Type *Ty, TTI::TargetCostKind CostKind, Instruction *Inst) { // Division by a constant can be turned into multiplication, but only if we // know it's constant. So it's not so much that the immediate is cheap (it's // not), but that the alternative is worse. // FIXME: this is probably unneeded with GlobalISel. if ((Opcode == Instruction::SDiv || Opcode == Instruction::UDiv || Opcode == Instruction::SRem || Opcode == Instruction::URem) && Idx == 1) return 0; // Leave any gep offsets for the CodeGenPrepare, which will do a better job at // splitting any large offsets. if (Opcode == Instruction::GetElementPtr && Idx != 0) return 0; if (Opcode == Instruction::And) { // UXTB/UXTH if (Imm == 255 || Imm == 65535) return 0; // Conversion to BIC is free, and means we can use ~Imm instead. return std::min(getIntImmCost(Imm, Ty, CostKind), getIntImmCost(~Imm, Ty, CostKind)); } if (Opcode == Instruction::Add) // Conversion to SUB is free, and means we can use -Imm instead. return std::min(getIntImmCost(Imm, Ty, CostKind), getIntImmCost(-Imm, Ty, CostKind)); if (Opcode == Instruction::ICmp && Imm.isNegative() && Ty->getIntegerBitWidth() == 32) { int64_t NegImm = -Imm.getSExtValue(); if (ST->isThumb2() && NegImm < 1<<12) // icmp X, #-C -> cmn X, #C return 0; if (ST->isThumb() && NegImm < 1<<8) // icmp X, #-C -> adds X, #C return 0; } // xor a, -1 can always be folded to MVN if (Opcode == Instruction::Xor && Imm.isAllOnes()) return 0; // Ensures negative constant of min(max()) or max(min()) patterns that // match to SSAT instructions don't get hoisted if (Inst && ((ST->hasV6Ops() && !ST->isThumb()) || ST->isThumb2()) && Ty->getIntegerBitWidth() <= 32) { if (isSSATMinMaxPattern(Inst, Imm) || (isa(Inst) && Inst->hasOneUse() && isSSATMinMaxPattern(cast(*Inst->user_begin()), Imm))) return 0; } if (Inst && ST->hasVFP2Base() && isFPSatMinMaxPattern(Inst, Imm)) return 0; // We can convert <= -1 to < 0, which is generally quite cheap. if (Inst && Opcode == Instruction::ICmp && Idx == 1 && Imm.isAllOnes()) { ICmpInst::Predicate Pred = cast(Inst)->getPredicate(); if (Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SLE) return std::min(getIntImmCost(Imm, Ty, CostKind), getIntImmCost(Imm + 1, Ty, CostKind)); } return getIntImmCost(Imm, Ty, CostKind); } InstructionCost ARMTTIImpl::getCFInstrCost(unsigned Opcode, TTI::TargetCostKind CostKind, const Instruction *I) { if (CostKind == TTI::TCK_RecipThroughput && (ST->hasNEON() || ST->hasMVEIntegerOps())) { // FIXME: The vectorizer is highly sensistive to the cost of these // instructions, which suggests that it may be using the costs incorrectly. // But, for now, just make them free to avoid performance regressions for // vector targets. return 0; } return BaseT::getCFInstrCost(Opcode, CostKind, I); } InstructionCost ARMTTIImpl::getCastInstrCost(unsigned Opcode, Type *Dst, Type *Src, TTI::CastContextHint CCH, TTI::TargetCostKind CostKind, const Instruction *I) { int ISD = TLI->InstructionOpcodeToISD(Opcode); assert(ISD && "Invalid opcode"); // TODO: Allow non-throughput costs that aren't binary. auto AdjustCost = [&CostKind](InstructionCost Cost) -> InstructionCost { if (CostKind != TTI::TCK_RecipThroughput) return Cost == 0 ? 0 : 1; return Cost; }; auto IsLegalFPType = [this](EVT VT) { EVT EltVT = VT.getScalarType(); return (EltVT == MVT::f32 && ST->hasVFP2Base()) || (EltVT == MVT::f64 && ST->hasFP64()) || (EltVT == MVT::f16 && ST->hasFullFP16()); }; EVT SrcTy = TLI->getValueType(DL, Src); EVT DstTy = TLI->getValueType(DL, Dst); if (!SrcTy.isSimple() || !DstTy.isSimple()) return AdjustCost( BaseT::getCastInstrCost(Opcode, Dst, Src, CCH, CostKind, I)); // Extending masked load/Truncating masked stores is expensive because we // currently don't split them. This means that we'll likely end up // loading/storing each element individually (hence the high cost). if ((ST->hasMVEIntegerOps() && (Opcode == Instruction::Trunc || Opcode == Instruction::ZExt || Opcode == Instruction::SExt)) || (ST->hasMVEFloatOps() && (Opcode == Instruction::FPExt || Opcode == Instruction::FPTrunc) && IsLegalFPType(SrcTy) && IsLegalFPType(DstTy))) if (CCH == TTI::CastContextHint::Masked && DstTy.getSizeInBits() > 128) return 2 * DstTy.getVectorNumElements() * ST->getMVEVectorCostFactor(CostKind); // The extend of other kinds of load is free if (CCH == TTI::CastContextHint::Normal || CCH == TTI::CastContextHint::Masked) { static const TypeConversionCostTblEntry LoadConversionTbl[] = { {ISD::SIGN_EXTEND, MVT::i32, MVT::i16, 0}, {ISD::ZERO_EXTEND, MVT::i32, MVT::i16, 0}, {ISD::SIGN_EXTEND, MVT::i32, MVT::i8, 0}, {ISD::ZERO_EXTEND, MVT::i32, MVT::i8, 0}, {ISD::SIGN_EXTEND, MVT::i16, MVT::i8, 0}, {ISD::ZERO_EXTEND, MVT::i16, MVT::i8, 0}, {ISD::SIGN_EXTEND, MVT::i64, MVT::i32, 1}, {ISD::ZERO_EXTEND, MVT::i64, MVT::i32, 1}, {ISD::SIGN_EXTEND, MVT::i64, MVT::i16, 1}, {ISD::ZERO_EXTEND, MVT::i64, MVT::i16, 1}, {ISD::SIGN_EXTEND, MVT::i64, MVT::i8, 1}, {ISD::ZERO_EXTEND, MVT::i64, MVT::i8, 1}, }; if (const auto *Entry = ConvertCostTableLookup( LoadConversionTbl, ISD, DstTy.getSimpleVT(), SrcTy.getSimpleVT())) return AdjustCost(Entry->Cost); static const TypeConversionCostTblEntry MVELoadConversionTbl[] = { {ISD::SIGN_EXTEND, MVT::v4i32, MVT::v4i16, 0}, {ISD::ZERO_EXTEND, MVT::v4i32, MVT::v4i16, 0}, {ISD::SIGN_EXTEND, MVT::v4i32, MVT::v4i8, 0}, {ISD::ZERO_EXTEND, MVT::v4i32, MVT::v4i8, 0}, {ISD::SIGN_EXTEND, MVT::v8i16, MVT::v8i8, 0}, {ISD::ZERO_EXTEND, MVT::v8i16, MVT::v8i8, 0}, // The following extend from a legal type to an illegal type, so need to // split the load. This introduced an extra load operation, but the // extend is still "free". {ISD::SIGN_EXTEND, MVT::v8i32, MVT::v8i16, 1}, {ISD::ZERO_EXTEND, MVT::v8i32, MVT::v8i16, 1}, {ISD::SIGN_EXTEND, MVT::v16i32, MVT::v16i8, 3}, {ISD::ZERO_EXTEND, MVT::v16i32, MVT::v16i8, 3}, {ISD::SIGN_EXTEND, MVT::v16i16, MVT::v16i8, 1}, {ISD::ZERO_EXTEND, MVT::v16i16, MVT::v16i8, 1}, }; if (SrcTy.isVector() && ST->hasMVEIntegerOps()) { if (const auto *Entry = ConvertCostTableLookup(MVELoadConversionTbl, ISD, DstTy.getSimpleVT(), SrcTy.getSimpleVT())) return Entry->Cost * ST->getMVEVectorCostFactor(CostKind); } static const TypeConversionCostTblEntry MVEFLoadConversionTbl[] = { // FPExtends are similar but also require the VCVT instructions. {ISD::FP_EXTEND, MVT::v4f32, MVT::v4f16, 1}, {ISD::FP_EXTEND, MVT::v8f32, MVT::v8f16, 3}, }; if (SrcTy.isVector() && ST->hasMVEFloatOps()) { if (const auto *Entry = ConvertCostTableLookup(MVEFLoadConversionTbl, ISD, DstTy.getSimpleVT(), SrcTy.getSimpleVT())) return Entry->Cost * ST->getMVEVectorCostFactor(CostKind); } // The truncate of a store is free. This is the mirror of extends above. static const TypeConversionCostTblEntry MVEStoreConversionTbl[] = { {ISD::TRUNCATE, MVT::v4i32, MVT::v4i16, 0}, {ISD::TRUNCATE, MVT::v4i32, MVT::v4i8, 0}, {ISD::TRUNCATE, MVT::v8i16, MVT::v8i8, 0}, {ISD::TRUNCATE, MVT::v8i32, MVT::v8i16, 1}, {ISD::TRUNCATE, MVT::v8i32, MVT::v8i8, 1}, {ISD::TRUNCATE, MVT::v16i32, MVT::v16i8, 3}, {ISD::TRUNCATE, MVT::v16i16, MVT::v16i8, 1}, }; if (SrcTy.isVector() && ST->hasMVEIntegerOps()) { if (const auto *Entry = ConvertCostTableLookup(MVEStoreConversionTbl, ISD, SrcTy.getSimpleVT(), DstTy.getSimpleVT())) return Entry->Cost * ST->getMVEVectorCostFactor(CostKind); } static const TypeConversionCostTblEntry MVEFStoreConversionTbl[] = { {ISD::FP_ROUND, MVT::v4f32, MVT::v4f16, 1}, {ISD::FP_ROUND, MVT::v8f32, MVT::v8f16, 3}, }; if (SrcTy.isVector() && ST->hasMVEFloatOps()) { if (const auto *Entry = ConvertCostTableLookup(MVEFStoreConversionTbl, ISD, SrcTy.getSimpleVT(), DstTy.getSimpleVT())) return Entry->Cost * ST->getMVEVectorCostFactor(CostKind); } } // NEON vector operations that can extend their inputs. if ((ISD == ISD::SIGN_EXTEND || ISD == ISD::ZERO_EXTEND) && I && I->hasOneUse() && ST->hasNEON() && SrcTy.isVector()) { static const TypeConversionCostTblEntry NEONDoubleWidthTbl[] = { // vaddl { ISD::ADD, MVT::v4i32, MVT::v4i16, 0 }, { ISD::ADD, MVT::v8i16, MVT::v8i8, 0 }, // vsubl { ISD::SUB, MVT::v4i32, MVT::v4i16, 0 }, { ISD::SUB, MVT::v8i16, MVT::v8i8, 0 }, // vmull { ISD::MUL, MVT::v4i32, MVT::v4i16, 0 }, { ISD::MUL, MVT::v8i16, MVT::v8i8, 0 }, // vshll { ISD::SHL, MVT::v4i32, MVT::v4i16, 0 }, { ISD::SHL, MVT::v8i16, MVT::v8i8, 0 }, }; auto *User = cast(*I->user_begin()); int UserISD = TLI->InstructionOpcodeToISD(User->getOpcode()); if (auto *Entry = ConvertCostTableLookup(NEONDoubleWidthTbl, UserISD, DstTy.getSimpleVT(), SrcTy.getSimpleVT())) { return AdjustCost(Entry->Cost); } } // Single to/from double precision conversions. if (Src->isVectorTy() && ST->hasNEON() && ((ISD == ISD::FP_ROUND && SrcTy.getScalarType() == MVT::f64 && DstTy.getScalarType() == MVT::f32) || (ISD == ISD::FP_EXTEND && SrcTy.getScalarType() == MVT::f32 && DstTy.getScalarType() == MVT::f64))) { static const CostTblEntry NEONFltDblTbl[] = { // Vector fptrunc/fpext conversions. {ISD::FP_ROUND, MVT::v2f64, 2}, {ISD::FP_EXTEND, MVT::v2f32, 2}, {ISD::FP_EXTEND, MVT::v4f32, 4}}; std::pair LT = getTypeLegalizationCost(Src); if (const auto *Entry = CostTableLookup(NEONFltDblTbl, ISD, LT.second)) return AdjustCost(LT.first * Entry->Cost); } // Some arithmetic, load and store operations have specific instructions // to cast up/down their types automatically at no extra cost. // TODO: Get these tables to know at least what the related operations are. static const TypeConversionCostTblEntry NEONVectorConversionTbl[] = { { ISD::SIGN_EXTEND, MVT::v4i32, MVT::v4i16, 1 }, { ISD::ZERO_EXTEND, MVT::v4i32, MVT::v4i16, 1 }, { ISD::SIGN_EXTEND, MVT::v2i64, MVT::v2i32, 1 }, { ISD::ZERO_EXTEND, MVT::v2i64, MVT::v2i32, 1 }, { ISD::TRUNCATE, MVT::v4i32, MVT::v4i64, 0 }, { ISD::TRUNCATE, MVT::v4i16, MVT::v4i32, 1 }, // The number of vmovl instructions for the extension. { ISD::SIGN_EXTEND, MVT::v8i16, MVT::v8i8, 1 }, { ISD::ZERO_EXTEND, MVT::v8i16, MVT::v8i8, 1 }, { ISD::SIGN_EXTEND, MVT::v4i32, MVT::v4i8, 2 }, { ISD::ZERO_EXTEND, MVT::v4i32, MVT::v4i8, 2 }, { ISD::SIGN_EXTEND, MVT::v2i64, MVT::v2i8, 3 }, { ISD::ZERO_EXTEND, MVT::v2i64, MVT::v2i8, 3 }, { ISD::SIGN_EXTEND, MVT::v2i64, MVT::v2i16, 2 }, { ISD::ZERO_EXTEND, MVT::v2i64, MVT::v2i16, 2 }, { ISD::SIGN_EXTEND, MVT::v4i64, MVT::v4i16, 3 }, { ISD::ZERO_EXTEND, MVT::v4i64, MVT::v4i16, 3 }, { ISD::SIGN_EXTEND, MVT::v8i32, MVT::v8i8, 3 }, { ISD::ZERO_EXTEND, MVT::v8i32, MVT::v8i8, 3 }, { 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::v16i32, MVT::v16i8, 6 }, { ISD::ZERO_EXTEND, MVT::v16i32, MVT::v16i8, 6 }, // Operations that we legalize using splitting. { ISD::TRUNCATE, MVT::v16i8, MVT::v16i32, 6 }, { ISD::TRUNCATE, MVT::v8i8, MVT::v8i32, 3 }, // Vector float <-> i32 conversions. { ISD::SINT_TO_FP, MVT::v4f32, MVT::v4i32, 1 }, { ISD::UINT_TO_FP, MVT::v4f32, MVT::v4i32, 1 }, { ISD::SINT_TO_FP, MVT::v2f32, MVT::v2i8, 3 }, { ISD::UINT_TO_FP, MVT::v2f32, MVT::v2i8, 3 }, { ISD::SINT_TO_FP, MVT::v2f32, MVT::v2i16, 2 }, { ISD::UINT_TO_FP, MVT::v2f32, MVT::v2i16, 2 }, { ISD::SINT_TO_FP, MVT::v2f32, MVT::v2i32, 1 }, { ISD::UINT_TO_FP, MVT::v2f32, MVT::v2i32, 1 }, { ISD::SINT_TO_FP, MVT::v4f32, MVT::v4i1, 3 }, { ISD::UINT_TO_FP, MVT::v4f32, MVT::v4i1, 3 }, { ISD::SINT_TO_FP, MVT::v4f32, MVT::v4i8, 3 }, { ISD::UINT_TO_FP, MVT::v4f32, MVT::v4i8, 3 }, { ISD::SINT_TO_FP, MVT::v4f32, MVT::v4i16, 2 }, { ISD::UINT_TO_FP, MVT::v4f32, MVT::v4i16, 2 }, { ISD::SINT_TO_FP, MVT::v8f32, MVT::v8i16, 4 }, { ISD::UINT_TO_FP, MVT::v8f32, MVT::v8i16, 4 }, { ISD::SINT_TO_FP, MVT::v8f32, MVT::v8i32, 2 }, { ISD::UINT_TO_FP, MVT::v8f32, MVT::v8i32, 2 }, { ISD::SINT_TO_FP, MVT::v16f32, MVT::v16i16, 8 }, { ISD::UINT_TO_FP, MVT::v16f32, MVT::v16i16, 8 }, { ISD::SINT_TO_FP, MVT::v16f32, MVT::v16i32, 4 }, { ISD::UINT_TO_FP, MVT::v16f32, MVT::v16i32, 4 }, { ISD::FP_TO_SINT, MVT::v4i32, MVT::v4f32, 1 }, { ISD::FP_TO_UINT, MVT::v4i32, MVT::v4f32, 1 }, { ISD::FP_TO_SINT, MVT::v4i8, MVT::v4f32, 3 }, { ISD::FP_TO_UINT, MVT::v4i8, MVT::v4f32, 3 }, { ISD::FP_TO_SINT, MVT::v4i16, MVT::v4f32, 2 }, { ISD::FP_TO_UINT, MVT::v4i16, MVT::v4f32, 2 }, // Vector double <-> i32 conversions. { ISD::SINT_TO_FP, MVT::v2f64, MVT::v2i32, 2 }, { ISD::UINT_TO_FP, MVT::v2f64, MVT::v2i32, 2 }, { ISD::SINT_TO_FP, MVT::v2f64, MVT::v2i8, 4 }, { ISD::UINT_TO_FP, MVT::v2f64, MVT::v2i8, 4 }, { ISD::SINT_TO_FP, MVT::v2f64, MVT::v2i16, 3 }, { ISD::UINT_TO_FP, MVT::v2f64, MVT::v2i16, 3 }, { ISD::SINT_TO_FP, MVT::v2f64, MVT::v2i32, 2 }, { ISD::UINT_TO_FP, MVT::v2f64, MVT::v2i32, 2 }, { ISD::FP_TO_SINT, MVT::v2i32, MVT::v2f64, 2 }, { ISD::FP_TO_UINT, MVT::v2i32, MVT::v2f64, 2 }, { ISD::FP_TO_SINT, MVT::v8i16, MVT::v8f32, 4 }, { ISD::FP_TO_UINT, MVT::v8i16, MVT::v8f32, 4 }, { ISD::FP_TO_SINT, MVT::v16i16, MVT::v16f32, 8 }, { ISD::FP_TO_UINT, MVT::v16i16, MVT::v16f32, 8 } }; if (SrcTy.isVector() && ST->hasNEON()) { if (const auto *Entry = ConvertCostTableLookup(NEONVectorConversionTbl, ISD, DstTy.getSimpleVT(), SrcTy.getSimpleVT())) return AdjustCost(Entry->Cost); } // Scalar float to integer conversions. static const TypeConversionCostTblEntry NEONFloatConversionTbl[] = { { ISD::FP_TO_SINT, MVT::i1, MVT::f32, 2 }, { ISD::FP_TO_UINT, MVT::i1, MVT::f32, 2 }, { ISD::FP_TO_SINT, MVT::i1, MVT::f64, 2 }, { ISD::FP_TO_UINT, MVT::i1, MVT::f64, 2 }, { ISD::FP_TO_SINT, MVT::i8, MVT::f32, 2 }, { ISD::FP_TO_UINT, MVT::i8, MVT::f32, 2 }, { ISD::FP_TO_SINT, MVT::i8, MVT::f64, 2 }, { ISD::FP_TO_UINT, MVT::i8, MVT::f64, 2 }, { ISD::FP_TO_SINT, MVT::i16, MVT::f32, 2 }, { ISD::FP_TO_UINT, MVT::i16, MVT::f32, 2 }, { ISD::FP_TO_SINT, MVT::i16, MVT::f64, 2 }, { ISD::FP_TO_UINT, MVT::i16, MVT::f64, 2 }, { ISD::FP_TO_SINT, MVT::i32, MVT::f32, 2 }, { ISD::FP_TO_UINT, MVT::i32, MVT::f32, 2 }, { ISD::FP_TO_SINT, MVT::i32, MVT::f64, 2 }, { ISD::FP_TO_UINT, MVT::i32, MVT::f64, 2 }, { ISD::FP_TO_SINT, MVT::i64, MVT::f32, 10 }, { ISD::FP_TO_UINT, MVT::i64, MVT::f32, 10 }, { ISD::FP_TO_SINT, MVT::i64, MVT::f64, 10 }, { ISD::FP_TO_UINT, MVT::i64, MVT::f64, 10 } }; if (SrcTy.isFloatingPoint() && ST->hasNEON()) { if (const auto *Entry = ConvertCostTableLookup(NEONFloatConversionTbl, ISD, DstTy.getSimpleVT(), SrcTy.getSimpleVT())) return AdjustCost(Entry->Cost); } // Scalar integer to float conversions. static const TypeConversionCostTblEntry NEONIntegerConversionTbl[] = { { ISD::SINT_TO_FP, MVT::f32, MVT::i1, 2 }, { ISD::UINT_TO_FP, MVT::f32, MVT::i1, 2 }, { ISD::SINT_TO_FP, MVT::f64, MVT::i1, 2 }, { ISD::UINT_TO_FP, MVT::f64, MVT::i1, 2 }, { ISD::SINT_TO_FP, MVT::f32, MVT::i8, 2 }, { ISD::UINT_TO_FP, MVT::f32, MVT::i8, 2 }, { ISD::SINT_TO_FP, MVT::f64, MVT::i8, 2 }, { ISD::UINT_TO_FP, MVT::f64, MVT::i8, 2 }, { ISD::SINT_TO_FP, MVT::f32, MVT::i16, 2 }, { ISD::UINT_TO_FP, MVT::f32, MVT::i16, 2 }, { ISD::SINT_TO_FP, MVT::f64, MVT::i16, 2 }, { ISD::UINT_TO_FP, MVT::f64, MVT::i16, 2 }, { ISD::SINT_TO_FP, MVT::f32, MVT::i32, 2 }, { ISD::UINT_TO_FP, MVT::f32, MVT::i32, 2 }, { ISD::SINT_TO_FP, MVT::f64, MVT::i32, 2 }, { ISD::UINT_TO_FP, MVT::f64, MVT::i32, 2 }, { ISD::SINT_TO_FP, MVT::f32, MVT::i64, 10 }, { ISD::UINT_TO_FP, MVT::f32, MVT::i64, 10 }, { ISD::SINT_TO_FP, MVT::f64, MVT::i64, 10 }, { ISD::UINT_TO_FP, MVT::f64, MVT::i64, 10 } }; if (SrcTy.isInteger() && ST->hasNEON()) { if (const auto *Entry = ConvertCostTableLookup(NEONIntegerConversionTbl, ISD, DstTy.getSimpleVT(), SrcTy.getSimpleVT())) return AdjustCost(Entry->Cost); } // MVE extend costs, taken from codegen tests. i8->i16 or i16->i32 is one // instruction, i8->i32 is two. i64 zexts are an VAND with a constant, sext // are linearised so take more. static const TypeConversionCostTblEntry MVEVectorConversionTbl[] = { { ISD::SIGN_EXTEND, MVT::v8i16, MVT::v8i8, 1 }, { ISD::ZERO_EXTEND, MVT::v8i16, MVT::v8i8, 1 }, { ISD::SIGN_EXTEND, MVT::v4i32, MVT::v4i8, 2 }, { ISD::ZERO_EXTEND, MVT::v4i32, MVT::v4i8, 2 }, { ISD::SIGN_EXTEND, MVT::v2i64, MVT::v2i8, 10 }, { ISD::ZERO_EXTEND, MVT::v2i64, MVT::v2i8, 2 }, { ISD::SIGN_EXTEND, MVT::v4i32, MVT::v4i16, 1 }, { ISD::ZERO_EXTEND, MVT::v4i32, MVT::v4i16, 1 }, { ISD::SIGN_EXTEND, MVT::v2i64, MVT::v2i16, 10 }, { ISD::ZERO_EXTEND, MVT::v2i64, MVT::v2i16, 2 }, { ISD::SIGN_EXTEND, MVT::v2i64, MVT::v2i32, 8 }, { ISD::ZERO_EXTEND, MVT::v2i64, MVT::v2i32, 2 }, }; if (SrcTy.isVector() && ST->hasMVEIntegerOps()) { if (const auto *Entry = ConvertCostTableLookup(MVEVectorConversionTbl, ISD, DstTy.getSimpleVT(), SrcTy.getSimpleVT())) return Entry->Cost * ST->getMVEVectorCostFactor(CostKind); } if (ISD == ISD::FP_ROUND || ISD == ISD::FP_EXTEND) { // As general rule, fp converts that were not matched above are scalarized // and cost 1 vcvt for each lane, so long as the instruction is available. // If not it will become a series of function calls. const InstructionCost CallCost = getCallInstrCost(nullptr, Dst, {Src}, CostKind); int Lanes = 1; if (SrcTy.isFixedLengthVector()) Lanes = SrcTy.getVectorNumElements(); if (IsLegalFPType(SrcTy) && IsLegalFPType(DstTy)) return Lanes; else return Lanes * CallCost; } if (ISD == ISD::TRUNCATE && ST->hasMVEIntegerOps() && SrcTy.isFixedLengthVector()) { // Treat a truncate with larger than legal source (128bits for MVE) as // expensive, 2 instructions per lane. if ((SrcTy.getScalarType() == MVT::i8 || SrcTy.getScalarType() == MVT::i16 || SrcTy.getScalarType() == MVT::i32) && SrcTy.getSizeInBits() > 128 && SrcTy.getSizeInBits() > DstTy.getSizeInBits()) return SrcTy.getVectorNumElements() * 2; } // Scalar integer conversion costs. static const TypeConversionCostTblEntry ARMIntegerConversionTbl[] = { // i16 -> i64 requires two dependent operations. { ISD::SIGN_EXTEND, MVT::i64, MVT::i16, 2 }, // Truncates on i64 are assumed to be free. { ISD::TRUNCATE, MVT::i32, MVT::i64, 0 }, { ISD::TRUNCATE, MVT::i16, MVT::i64, 0 }, { ISD::TRUNCATE, MVT::i8, MVT::i64, 0 }, { ISD::TRUNCATE, MVT::i1, MVT::i64, 0 } }; if (SrcTy.isInteger()) { if (const auto *Entry = ConvertCostTableLookup(ARMIntegerConversionTbl, ISD, DstTy.getSimpleVT(), SrcTy.getSimpleVT())) return AdjustCost(Entry->Cost); } int BaseCost = ST->hasMVEIntegerOps() && Src->isVectorTy() ? ST->getMVEVectorCostFactor(CostKind) : 1; return AdjustCost( BaseCost * BaseT::getCastInstrCost(Opcode, Dst, Src, CCH, CostKind, I)); } InstructionCost ARMTTIImpl::getVectorInstrCost(unsigned Opcode, Type *ValTy, TTI::TargetCostKind CostKind, unsigned Index, Value *Op0, Value *Op1) { // Penalize inserting into an D-subregister. We end up with a three times // lower estimated throughput on swift. if (ST->hasSlowLoadDSubregister() && Opcode == Instruction::InsertElement && ValTy->isVectorTy() && ValTy->getScalarSizeInBits() <= 32) return 3; if (ST->hasNEON() && (Opcode == Instruction::InsertElement || Opcode == Instruction::ExtractElement)) { // Cross-class copies are expensive on many microarchitectures, // so assume they are expensive by default. if (cast(ValTy)->getElementType()->isIntegerTy()) return 3; // Even if it's not a cross class copy, this likely leads to mixing // of NEON and VFP code and should be therefore penalized. if (ValTy->isVectorTy() && ValTy->getScalarSizeInBits() <= 32) return std::max( BaseT::getVectorInstrCost(Opcode, ValTy, CostKind, Index, Op0, Op1), 2U); } if (ST->hasMVEIntegerOps() && (Opcode == Instruction::InsertElement || Opcode == Instruction::ExtractElement)) { // Integer cross-lane moves are more expensive than float, which can // sometimes just be vmovs. Integer involve being passes to GPR registers, // causing more of a delay. std::pair LT = getTypeLegalizationCost(ValTy->getScalarType()); return LT.first * (ValTy->getScalarType()->isIntegerTy() ? 4 : 1); } return BaseT::getVectorInstrCost(Opcode, ValTy, CostKind, Index, Op0, Op1); } InstructionCost ARMTTIImpl::getCmpSelInstrCost(unsigned Opcode, Type *ValTy, Type *CondTy, CmpInst::Predicate VecPred, TTI::TargetCostKind CostKind, const Instruction *I) { int ISD = TLI->InstructionOpcodeToISD(Opcode); // Thumb scalar code size cost for select. if (CostKind == TTI::TCK_CodeSize && ISD == ISD::SELECT && ST->isThumb() && !ValTy->isVectorTy()) { // Assume expensive structs. if (TLI->getValueType(DL, ValTy, true) == MVT::Other) return TTI::TCC_Expensive; // Select costs can vary because they: // - may require one or more conditional mov (including an IT), // - can't operate directly on immediates, // - require live flags, which we can't copy around easily. InstructionCost Cost = getTypeLegalizationCost(ValTy).first; // Possible IT instruction for Thumb2, or more for Thumb1. ++Cost; // i1 values may need rematerialising by using mov immediates and/or // flag setting instructions. if (ValTy->isIntegerTy(1)) ++Cost; return Cost; } // If this is a vector min/max/abs, use the cost of that intrinsic directly // instead. Hopefully when min/max intrinsics are more prevalent this code // will not be needed. const Instruction *Sel = I; if ((Opcode == Instruction::ICmp || Opcode == Instruction::FCmp) && Sel && Sel->hasOneUse()) Sel = cast(Sel->user_back()); if (Sel && ValTy->isVectorTy() && (ValTy->isIntOrIntVectorTy() || ValTy->isFPOrFPVectorTy())) { const Value *LHS, *RHS; SelectPatternFlavor SPF = matchSelectPattern(Sel, LHS, RHS).Flavor; unsigned IID = 0; switch (SPF) { case SPF_ABS: IID = Intrinsic::abs; break; case SPF_SMIN: IID = Intrinsic::smin; break; case SPF_SMAX: IID = Intrinsic::smax; break; case SPF_UMIN: IID = Intrinsic::umin; break; case SPF_UMAX: IID = Intrinsic::umax; break; case SPF_FMINNUM: IID = Intrinsic::minnum; break; case SPF_FMAXNUM: IID = Intrinsic::maxnum; break; default: break; } if (IID) { // The ICmp is free, the select gets the cost of the min/max/etc if (Sel != I) return 0; IntrinsicCostAttributes CostAttrs(IID, ValTy, {ValTy, ValTy}); return getIntrinsicInstrCost(CostAttrs, CostKind); } } // On NEON a vector select gets lowered to vbsl. if (ST->hasNEON() && ValTy->isVectorTy() && ISD == ISD::SELECT && CondTy) { // Lowering of some vector selects is currently far from perfect. static const TypeConversionCostTblEntry NEONVectorSelectTbl[] = { { ISD::SELECT, MVT::v4i1, MVT::v4i64, 4*4 + 1*2 + 1 }, { ISD::SELECT, MVT::v8i1, MVT::v8i64, 50 }, { ISD::SELECT, MVT::v16i1, MVT::v16i64, 100 } }; EVT SelCondTy = TLI->getValueType(DL, CondTy); EVT SelValTy = TLI->getValueType(DL, ValTy); if (SelCondTy.isSimple() && SelValTy.isSimple()) { if (const auto *Entry = ConvertCostTableLookup(NEONVectorSelectTbl, ISD, SelCondTy.getSimpleVT(), SelValTy.getSimpleVT())) return Entry->Cost; } std::pair LT = getTypeLegalizationCost(ValTy); return LT.first; } if (ST->hasMVEIntegerOps() && ValTy->isVectorTy() && (Opcode == Instruction::ICmp || Opcode == Instruction::FCmp) && cast(ValTy)->getNumElements() > 1) { FixedVectorType *VecValTy = cast(ValTy); FixedVectorType *VecCondTy = dyn_cast_or_null(CondTy); if (!VecCondTy) VecCondTy = cast(CmpInst::makeCmpResultType(VecValTy)); // If we don't have mve.fp any fp operations will need to be scalarized. if (Opcode == Instruction::FCmp && !ST->hasMVEFloatOps()) { // One scalaization insert, one scalarization extract and the cost of the // fcmps. return BaseT::getScalarizationOverhead(VecValTy, /*Insert*/ false, /*Extract*/ true, CostKind) + BaseT::getScalarizationOverhead(VecCondTy, /*Insert*/ true, /*Extract*/ false, CostKind) + VecValTy->getNumElements() * getCmpSelInstrCost(Opcode, ValTy->getScalarType(), VecCondTy->getScalarType(), VecPred, CostKind, I); } std::pair LT = getTypeLegalizationCost(ValTy); int BaseCost = ST->getMVEVectorCostFactor(CostKind); // There are two types - the input that specifies the type of the compare // and the output vXi1 type. Because we don't know how the output will be // split, we may need an expensive shuffle to get two in sync. This has the // effect of making larger than legal compares (v8i32 for example) // expensive. if (LT.second.isVector() && LT.second.getVectorNumElements() > 2) { if (LT.first > 1) return LT.first * BaseCost + BaseT::getScalarizationOverhead(VecCondTy, /*Insert*/ true, /*Extract*/ false, CostKind); return BaseCost; } } // Default to cheap (throughput/size of 1 instruction) but adjust throughput // for "multiple beats" potentially needed by MVE instructions. int BaseCost = 1; if (ST->hasMVEIntegerOps() && ValTy->isVectorTy()) BaseCost = ST->getMVEVectorCostFactor(CostKind); return BaseCost * BaseT::getCmpSelInstrCost(Opcode, ValTy, CondTy, VecPred, CostKind, I); } InstructionCost ARMTTIImpl::getAddressComputationCost(Type *Ty, ScalarEvolution *SE, const SCEV *Ptr) { // 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; int MaxMergeDistance = 64; if (ST->hasNEON()) { if (Ty->isVectorTy() && SE && !BaseT::isConstantStridedAccessLessThan(SE, Ptr, MaxMergeDistance + 1)) return NumVectorInstToHideOverhead; // In many cases the address computation is not merged into the instruction // addressing mode. return 1; } return BaseT::getAddressComputationCost(Ty, SE, Ptr); } bool ARMTTIImpl::isProfitableLSRChainElement(Instruction *I) { if (IntrinsicInst *II = dyn_cast(I)) { // If a VCTP is part of a chain, it's already profitable and shouldn't be // optimized, else LSR may block tail-predication. switch (II->getIntrinsicID()) { case Intrinsic::arm_mve_vctp8: case Intrinsic::arm_mve_vctp16: case Intrinsic::arm_mve_vctp32: case Intrinsic::arm_mve_vctp64: return true; default: break; } } return false; } bool ARMTTIImpl::isLegalMaskedLoad(Type *DataTy, Align Alignment) { if (!EnableMaskedLoadStores || !ST->hasMVEIntegerOps()) return false; if (auto *VecTy = dyn_cast(DataTy)) { // Don't support v2i1 yet. if (VecTy->getNumElements() == 2) return false; // We don't support extending fp types. unsigned VecWidth = DataTy->getPrimitiveSizeInBits(); if (VecWidth != 128 && VecTy->getElementType()->isFloatingPointTy()) return false; } unsigned EltWidth = DataTy->getScalarSizeInBits(); return (EltWidth == 32 && Alignment >= 4) || (EltWidth == 16 && Alignment >= 2) || (EltWidth == 8); } bool ARMTTIImpl::isLegalMaskedGather(Type *Ty, Align Alignment) { if (!EnableMaskedGatherScatters || !ST->hasMVEIntegerOps()) return false; unsigned EltWidth = Ty->getScalarSizeInBits(); return ((EltWidth == 32 && Alignment >= 4) || (EltWidth == 16 && Alignment >= 2) || EltWidth == 8); } /// Given a memcpy/memset/memmove instruction, return the number of memory /// operations performed, via querying findOptimalMemOpLowering. Returns -1 if a /// call is used. int ARMTTIImpl::getNumMemOps(const IntrinsicInst *I) const { MemOp MOp; unsigned DstAddrSpace = ~0u; unsigned SrcAddrSpace = ~0u; const Function *F = I->getParent()->getParent(); if (const auto *MC = dyn_cast(I)) { ConstantInt *C = dyn_cast(MC->getLength()); // If 'size' is not a constant, a library call will be generated. if (!C) return -1; const unsigned Size = C->getValue().getZExtValue(); const Align DstAlign = *MC->getDestAlign(); const Align SrcAlign = *MC->getSourceAlign(); MOp = MemOp::Copy(Size, /*DstAlignCanChange*/ false, DstAlign, SrcAlign, /*IsVolatile*/ false); DstAddrSpace = MC->getDestAddressSpace(); SrcAddrSpace = MC->getSourceAddressSpace(); } else if (const auto *MS = dyn_cast(I)) { ConstantInt *C = dyn_cast(MS->getLength()); // If 'size' is not a constant, a library call will be generated. if (!C) return -1; const unsigned Size = C->getValue().getZExtValue(); const Align DstAlign = *MS->getDestAlign(); MOp = MemOp::Set(Size, /*DstAlignCanChange*/ false, DstAlign, /*IsZeroMemset*/ false, /*IsVolatile*/ false); DstAddrSpace = MS->getDestAddressSpace(); } else llvm_unreachable("Expected a memcpy/move or memset!"); unsigned Limit, Factor = 2; switch(I->getIntrinsicID()) { case Intrinsic::memcpy: Limit = TLI->getMaxStoresPerMemcpy(F->hasMinSize()); break; case Intrinsic::memmove: Limit = TLI->getMaxStoresPerMemmove(F->hasMinSize()); break; case Intrinsic::memset: Limit = TLI->getMaxStoresPerMemset(F->hasMinSize()); Factor = 1; break; default: llvm_unreachable("Expected a memcpy/move or memset!"); } // MemOps will be poplulated with a list of data types that needs to be // loaded and stored. That's why we multiply the number of elements by 2 to // get the cost for this memcpy. std::vector MemOps; if (getTLI()->findOptimalMemOpLowering( MemOps, Limit, MOp, DstAddrSpace, SrcAddrSpace, F->getAttributes())) return MemOps.size() * Factor; // If we can't find an optimal memop lowering, return the default cost return -1; } InstructionCost ARMTTIImpl::getMemcpyCost(const Instruction *I) { int NumOps = getNumMemOps(cast(I)); // To model the cost of a library call, we assume 1 for the call, and // 3 for the argument setup. if (NumOps == -1) return 4; return NumOps; } InstructionCost ARMTTIImpl::getShuffleCost(TTI::ShuffleKind Kind, VectorType *Tp, ArrayRef Mask, TTI::TargetCostKind CostKind, int Index, VectorType *SubTp, ArrayRef Args, const Instruction *CxtI) { Kind = improveShuffleKindFromMask(Kind, Mask, Tp, Index, SubTp); // Treat extractsubvector as single op permutation. bool IsExtractSubvector = Kind == TTI::SK_ExtractSubvector; if (IsExtractSubvector) Kind = TTI::SK_PermuteSingleSrc; if (ST->hasNEON()) { if (Kind == TTI::SK_Broadcast) { static const CostTblEntry NEONDupTbl[] = { // VDUP handles these cases. {ISD::VECTOR_SHUFFLE, MVT::v2i32, 1}, {ISD::VECTOR_SHUFFLE, MVT::v2f32, 1}, {ISD::VECTOR_SHUFFLE, MVT::v2i64, 1}, {ISD::VECTOR_SHUFFLE, MVT::v2f64, 1}, {ISD::VECTOR_SHUFFLE, MVT::v4i16, 1}, {ISD::VECTOR_SHUFFLE, MVT::v8i8, 1}, {ISD::VECTOR_SHUFFLE, MVT::v4i32, 1}, {ISD::VECTOR_SHUFFLE, MVT::v4f32, 1}, {ISD::VECTOR_SHUFFLE, MVT::v8i16, 1}, {ISD::VECTOR_SHUFFLE, MVT::v16i8, 1}}; std::pair LT = getTypeLegalizationCost(Tp); if (const auto *Entry = CostTableLookup(NEONDupTbl, ISD::VECTOR_SHUFFLE, LT.second)) return LT.first * Entry->Cost; } if (Kind == TTI::SK_Reverse) { static const CostTblEntry NEONShuffleTbl[] = { // Reverse shuffle cost one instruction if we are shuffling within a // double word (vrev) or two if we shuffle a quad word (vrev, vext). {ISD::VECTOR_SHUFFLE, MVT::v2i32, 1}, {ISD::VECTOR_SHUFFLE, MVT::v2f32, 1}, {ISD::VECTOR_SHUFFLE, MVT::v2i64, 1}, {ISD::VECTOR_SHUFFLE, MVT::v2f64, 1}, {ISD::VECTOR_SHUFFLE, MVT::v4i16, 1}, {ISD::VECTOR_SHUFFLE, MVT::v8i8, 1}, {ISD::VECTOR_SHUFFLE, MVT::v4i32, 2}, {ISD::VECTOR_SHUFFLE, MVT::v4f32, 2}, {ISD::VECTOR_SHUFFLE, MVT::v8i16, 2}, {ISD::VECTOR_SHUFFLE, MVT::v16i8, 2}}; std::pair LT = getTypeLegalizationCost(Tp); if (const auto *Entry = CostTableLookup(NEONShuffleTbl, ISD::VECTOR_SHUFFLE, LT.second)) return LT.first * Entry->Cost; } if (Kind == TTI::SK_Select) { static const CostTblEntry NEONSelShuffleTbl[] = { // Select shuffle cost table for ARM. Cost is the number of // instructions // required to create the shuffled vector. {ISD::VECTOR_SHUFFLE, MVT::v2f32, 1}, {ISD::VECTOR_SHUFFLE, MVT::v2i64, 1}, {ISD::VECTOR_SHUFFLE, MVT::v2f64, 1}, {ISD::VECTOR_SHUFFLE, MVT::v2i32, 1}, {ISD::VECTOR_SHUFFLE, MVT::v4i32, 2}, {ISD::VECTOR_SHUFFLE, MVT::v4f32, 2}, {ISD::VECTOR_SHUFFLE, MVT::v4i16, 2}, {ISD::VECTOR_SHUFFLE, MVT::v8i16, 16}, {ISD::VECTOR_SHUFFLE, MVT::v16i8, 32}}; std::pair LT = getTypeLegalizationCost(Tp); if (const auto *Entry = CostTableLookup(NEONSelShuffleTbl, ISD::VECTOR_SHUFFLE, LT.second)) return LT.first * Entry->Cost; } } if (ST->hasMVEIntegerOps()) { if (Kind == TTI::SK_Broadcast) { static const CostTblEntry MVEDupTbl[] = { // VDUP handles these cases. {ISD::VECTOR_SHUFFLE, MVT::v4i32, 1}, {ISD::VECTOR_SHUFFLE, MVT::v8i16, 1}, {ISD::VECTOR_SHUFFLE, MVT::v16i8, 1}, {ISD::VECTOR_SHUFFLE, MVT::v4f32, 1}, {ISD::VECTOR_SHUFFLE, MVT::v8f16, 1}}; std::pair LT = getTypeLegalizationCost(Tp); if (const auto *Entry = CostTableLookup(MVEDupTbl, ISD::VECTOR_SHUFFLE, LT.second)) return LT.first * Entry->Cost * ST->getMVEVectorCostFactor(TTI::TCK_RecipThroughput); } if (!Mask.empty()) { std::pair LT = getTypeLegalizationCost(Tp); if (LT.second.isVector() && Mask.size() <= LT.second.getVectorNumElements() && (isVREVMask(Mask, LT.second, 16) || isVREVMask(Mask, LT.second, 32) || isVREVMask(Mask, LT.second, 64))) return ST->getMVEVectorCostFactor(TTI::TCK_RecipThroughput) * LT.first; } } // Restore optimal kind. if (IsExtractSubvector) Kind = TTI::SK_ExtractSubvector; int BaseCost = ST->hasMVEIntegerOps() && Tp->isVectorTy() ? ST->getMVEVectorCostFactor(TTI::TCK_RecipThroughput) : 1; return BaseCost * BaseT::getShuffleCost(Kind, Tp, Mask, CostKind, Index, SubTp); } InstructionCost ARMTTIImpl::getArithmeticInstrCost( unsigned Opcode, Type *Ty, TTI::TargetCostKind CostKind, TTI::OperandValueInfo Op1Info, TTI::OperandValueInfo Op2Info, ArrayRef Args, const Instruction *CxtI) { int ISDOpcode = TLI->InstructionOpcodeToISD(Opcode); if (ST->isThumb() && CostKind == TTI::TCK_CodeSize && Ty->isIntegerTy(1)) { // Make operations on i1 relatively expensive as this often involves // combining predicates. AND and XOR should be easier to handle with IT // blocks. switch (ISDOpcode) { default: break; case ISD::AND: case ISD::XOR: return 2; case ISD::OR: return 3; } } std::pair LT = getTypeLegalizationCost(Ty); if (ST->hasNEON()) { const unsigned FunctionCallDivCost = 20; const unsigned ReciprocalDivCost = 10; static const CostTblEntry CostTbl[] = { // Division. // These costs are somewhat random. Choose a cost of 20 to indicate that // vectorizing devision (added function call) is going to be very expensive. // Double registers types. { ISD::SDIV, MVT::v1i64, 1 * FunctionCallDivCost}, { ISD::UDIV, MVT::v1i64, 1 * FunctionCallDivCost}, { ISD::SREM, MVT::v1i64, 1 * FunctionCallDivCost}, { ISD::UREM, MVT::v1i64, 1 * FunctionCallDivCost}, { ISD::SDIV, MVT::v2i32, 2 * FunctionCallDivCost}, { ISD::UDIV, MVT::v2i32, 2 * FunctionCallDivCost}, { ISD::SREM, MVT::v2i32, 2 * FunctionCallDivCost}, { ISD::UREM, MVT::v2i32, 2 * FunctionCallDivCost}, { ISD::SDIV, MVT::v4i16, ReciprocalDivCost}, { ISD::UDIV, MVT::v4i16, ReciprocalDivCost}, { ISD::SREM, MVT::v4i16, 4 * FunctionCallDivCost}, { ISD::UREM, MVT::v4i16, 4 * FunctionCallDivCost}, { ISD::SDIV, MVT::v8i8, ReciprocalDivCost}, { ISD::UDIV, MVT::v8i8, ReciprocalDivCost}, { ISD::SREM, MVT::v8i8, 8 * FunctionCallDivCost}, { ISD::UREM, MVT::v8i8, 8 * FunctionCallDivCost}, // Quad register types. { ISD::SDIV, MVT::v2i64, 2 * FunctionCallDivCost}, { ISD::UDIV, MVT::v2i64, 2 * FunctionCallDivCost}, { ISD::SREM, MVT::v2i64, 2 * FunctionCallDivCost}, { ISD::UREM, MVT::v2i64, 2 * FunctionCallDivCost}, { ISD::SDIV, MVT::v4i32, 4 * FunctionCallDivCost}, { ISD::UDIV, MVT::v4i32, 4 * FunctionCallDivCost}, { ISD::SREM, MVT::v4i32, 4 * FunctionCallDivCost}, { ISD::UREM, MVT::v4i32, 4 * FunctionCallDivCost}, { ISD::SDIV, MVT::v8i16, 8 * FunctionCallDivCost}, { ISD::UDIV, MVT::v8i16, 8 * FunctionCallDivCost}, { ISD::SREM, MVT::v8i16, 8 * FunctionCallDivCost}, { ISD::UREM, MVT::v8i16, 8 * FunctionCallDivCost}, { ISD::SDIV, MVT::v16i8, 16 * FunctionCallDivCost}, { ISD::UDIV, MVT::v16i8, 16 * FunctionCallDivCost}, { ISD::SREM, MVT::v16i8, 16 * FunctionCallDivCost}, { ISD::UREM, MVT::v16i8, 16 * FunctionCallDivCost}, // Multiplication. }; if (const auto *Entry = CostTableLookup(CostTbl, ISDOpcode, LT.second)) return LT.first * Entry->Cost; InstructionCost Cost = BaseT::getArithmeticInstrCost( Opcode, Ty, CostKind, Op1Info, Op2Info); // This is somewhat of a hack. The problem that we are facing is that SROA // creates a sequence of shift, and, or instructions to construct values. // These sequences are recognized by the ISel and have zero-cost. Not so for // the vectorized code. Because we have support for v2i64 but not i64 those // sequences look particularly beneficial to vectorize. // To work around this we increase the cost of v2i64 operations to make them // seem less beneficial. if (LT.second == MVT::v2i64 && Op2Info.isUniform() && Op2Info.isConstant()) Cost += 4; return Cost; } // If this operation is a shift on arm/thumb2, it might well be folded into // the following instruction, hence having a cost of 0. auto LooksLikeAFreeShift = [&]() { if (ST->isThumb1Only() || Ty->isVectorTy()) return false; if (!CxtI || !CxtI->hasOneUse() || !CxtI->isShift()) return false; if (!Op2Info.isUniform() || !Op2Info.isConstant()) return false; // Folded into a ADC/ADD/AND/BIC/CMP/EOR/MVN/ORR/ORN/RSB/SBC/SUB switch (cast(CxtI->user_back())->getOpcode()) { case Instruction::Add: case Instruction::Sub: case Instruction::And: case Instruction::Xor: case Instruction::Or: case Instruction::ICmp: return true; default: return false; } }; if (LooksLikeAFreeShift()) return 0; // Default to cheap (throughput/size of 1 instruction) but adjust throughput // for "multiple beats" potentially needed by MVE instructions. int BaseCost = 1; if (ST->hasMVEIntegerOps() && Ty->isVectorTy()) BaseCost = ST->getMVEVectorCostFactor(CostKind); // The rest of this mostly follows what is done in BaseT::getArithmeticInstrCost, // without treating floats as more expensive that scalars or increasing the // costs for custom operations. The results is also multiplied by the // MVEVectorCostFactor where appropriate. if (TLI->isOperationLegalOrCustomOrPromote(ISDOpcode, LT.second)) return LT.first * BaseCost; // Else this is expand, assume that we need to scalarize this op. if (auto *VTy = dyn_cast(Ty)) { unsigned Num = VTy->getNumElements(); InstructionCost Cost = getArithmeticInstrCost(Opcode, Ty->getScalarType(), CostKind); // Return the cost of multiple scalar invocation plus the cost of // inserting and extracting the values. SmallVector Tys(Args.size(), Ty); return BaseT::getScalarizationOverhead(VTy, Args, Tys, CostKind) + Num * Cost; } return BaseCost; } InstructionCost ARMTTIImpl::getMemoryOpCost(unsigned Opcode, Type *Src, MaybeAlign Alignment, unsigned AddressSpace, TTI::TargetCostKind CostKind, TTI::OperandValueInfo OpInfo, const Instruction *I) { // TODO: Handle other cost kinds. if (CostKind != TTI::TCK_RecipThroughput) return 1; // Type legalization can't handle structs if (TLI->getValueType(DL, Src, true) == MVT::Other) return BaseT::getMemoryOpCost(Opcode, Src, Alignment, AddressSpace, CostKind); if (ST->hasNEON() && Src->isVectorTy() && (Alignment && *Alignment != Align(16)) && cast(Src)->getElementType()->isDoubleTy()) { // Unaligned loads/stores are extremely inefficient. // We need 4 uops for vst.1/vld.1 vs 1uop for vldr/vstr. std::pair LT = getTypeLegalizationCost(Src); return LT.first * 4; } // MVE can optimize a fpext(load(4xhalf)) using an extending integer load. // Same for stores. if (ST->hasMVEFloatOps() && isa(Src) && I && ((Opcode == Instruction::Load && I->hasOneUse() && isa(*I->user_begin())) || (Opcode == Instruction::Store && isa(I->getOperand(0))))) { FixedVectorType *SrcVTy = cast(Src); Type *DstTy = Opcode == Instruction::Load ? (*I->user_begin())->getType() : cast(I->getOperand(0))->getOperand(0)->getType(); if (SrcVTy->getNumElements() == 4 && SrcVTy->getScalarType()->isHalfTy() && DstTy->getScalarType()->isFloatTy()) return ST->getMVEVectorCostFactor(CostKind); } int BaseCost = ST->hasMVEIntegerOps() && Src->isVectorTy() ? ST->getMVEVectorCostFactor(CostKind) : 1; return BaseCost * BaseT::getMemoryOpCost(Opcode, Src, Alignment, AddressSpace, CostKind, OpInfo, I); } InstructionCost ARMTTIImpl::getMaskedMemoryOpCost(unsigned Opcode, Type *Src, Align Alignment, unsigned AddressSpace, TTI::TargetCostKind CostKind) { if (ST->hasMVEIntegerOps()) { if (Opcode == Instruction::Load && isLegalMaskedLoad(Src, Alignment)) return ST->getMVEVectorCostFactor(CostKind); if (Opcode == Instruction::Store && isLegalMaskedStore(Src, Alignment)) return ST->getMVEVectorCostFactor(CostKind); } if (!isa(Src)) return BaseT::getMaskedMemoryOpCost(Opcode, Src, Alignment, AddressSpace, CostKind); // Scalar cost, which is currently very high due to the efficiency of the // generated code. return cast(Src)->getNumElements() * 8; } InstructionCost ARMTTIImpl::getInterleavedMemoryOpCost( unsigned Opcode, Type *VecTy, unsigned Factor, ArrayRef Indices, Align Alignment, unsigned AddressSpace, TTI::TargetCostKind CostKind, bool UseMaskForCond, bool UseMaskForGaps) { assert(Factor >= 2 && "Invalid interleave factor"); assert(isa(VecTy) && "Expect a vector type"); // vldN/vstN doesn't support vector types of i64/f64 element. bool EltIs64Bits = DL.getTypeSizeInBits(VecTy->getScalarType()) == 64; if (Factor <= TLI->getMaxSupportedInterleaveFactor() && !EltIs64Bits && !UseMaskForCond && !UseMaskForGaps) { unsigned NumElts = cast(VecTy)->getNumElements(); auto *SubVecTy = FixedVectorType::get(VecTy->getScalarType(), NumElts / Factor); // vldN/vstN only support legal vector types of size 64 or 128 in bits. // Accesses having vector types that are a multiple of 128 bits can be // matched to more than one vldN/vstN instruction. int BaseCost = ST->hasMVEIntegerOps() ? ST->getMVEVectorCostFactor(CostKind) : 1; if (NumElts % Factor == 0 && TLI->isLegalInterleavedAccessType(Factor, SubVecTy, Alignment, DL)) return Factor * BaseCost * TLI->getNumInterleavedAccesses(SubVecTy, DL); // Some smaller than legal interleaved patterns are cheap as we can make // use of the vmovn or vrev patterns to interleave a standard load. This is // true for v4i8, v8i8 and v4i16 at least (but not for v4f16 as it is // promoted differently). The cost of 2 here is then a load and vrev or // vmovn. if (ST->hasMVEIntegerOps() && Factor == 2 && NumElts / Factor > 2 && VecTy->isIntOrIntVectorTy() && DL.getTypeSizeInBits(SubVecTy).getFixedValue() <= 64) return 2 * BaseCost; } return BaseT::getInterleavedMemoryOpCost(Opcode, VecTy, Factor, Indices, Alignment, AddressSpace, CostKind, UseMaskForCond, UseMaskForGaps); } InstructionCost ARMTTIImpl::getGatherScatterOpCost( unsigned Opcode, Type *DataTy, const Value *Ptr, bool VariableMask, Align Alignment, TTI::TargetCostKind CostKind, const Instruction *I) { using namespace PatternMatch; if (!ST->hasMVEIntegerOps() || !EnableMaskedGatherScatters) return BaseT::getGatherScatterOpCost(Opcode, DataTy, Ptr, VariableMask, Alignment, CostKind, I); assert(DataTy->isVectorTy() && "Can't do gather/scatters on scalar!"); auto *VTy = cast(DataTy); // TODO: Splitting, once we do that. unsigned NumElems = VTy->getNumElements(); unsigned EltSize = VTy->getScalarSizeInBits(); std::pair LT = getTypeLegalizationCost(DataTy); // For now, it is assumed that for the MVE gather instructions the loads are // all effectively serialised. This means the cost is the scalar cost // multiplied by the number of elements being loaded. This is possibly very // conservative, but even so we still end up vectorising loops because the // cost per iteration for many loops is lower than for scalar loops. InstructionCost VectorCost = NumElems * LT.first * ST->getMVEVectorCostFactor(CostKind); // The scalarization cost should be a lot higher. We use the number of vector // elements plus the scalarization overhead. If masking is required then a lot // of little blocks will be needed and potentially a scalarized p0 mask, // greatly increasing the cost. InstructionCost ScalarCost = NumElems * LT.first + (VariableMask ? NumElems * 5 : 0) + BaseT::getScalarizationOverhead(VTy, /*Insert*/ true, /*Extract*/ false, CostKind) + BaseT::getScalarizationOverhead(VTy, /*Insert*/ false, /*Extract*/ true, CostKind); if (EltSize < 8 || Alignment < EltSize / 8) return ScalarCost; unsigned ExtSize = EltSize; // Check whether there's a single user that asks for an extended type if (I != nullptr) { // Dependent of the caller of this function, a gather instruction will // either have opcode Instruction::Load or be a call to the masked_gather // intrinsic if ((I->getOpcode() == Instruction::Load || match(I, m_Intrinsic())) && I->hasOneUse()) { const User *Us = *I->users().begin(); if (isa(Us) || isa(Us)) { // only allow valid type combinations unsigned TypeSize = cast(Us)->getType()->getScalarSizeInBits(); if (((TypeSize == 32 && (EltSize == 8 || EltSize == 16)) || (TypeSize == 16 && EltSize == 8)) && TypeSize * NumElems == 128) { ExtSize = TypeSize; } } } // Check whether the input data needs to be truncated TruncInst *T; if ((I->getOpcode() == Instruction::Store || match(I, m_Intrinsic())) && (T = dyn_cast(I->getOperand(0)))) { // Only allow valid type combinations unsigned TypeSize = T->getOperand(0)->getType()->getScalarSizeInBits(); if (((EltSize == 16 && TypeSize == 32) || (EltSize == 8 && (TypeSize == 32 || TypeSize == 16))) && TypeSize * NumElems == 128) ExtSize = TypeSize; } } if (ExtSize * NumElems != 128 || NumElems < 4) return ScalarCost; // Any (aligned) i32 gather will not need to be scalarised. if (ExtSize == 32) return VectorCost; // For smaller types, we need to ensure that the gep's inputs are correctly // extended from a small enough value. Other sizes (including i64) are // scalarized for now. if (ExtSize != 8 && ExtSize != 16) return ScalarCost; if (const auto *BC = dyn_cast(Ptr)) Ptr = BC->getOperand(0); if (const auto *GEP = dyn_cast(Ptr)) { if (GEP->getNumOperands() != 2) return ScalarCost; unsigned Scale = DL.getTypeAllocSize(GEP->getResultElementType()); // Scale needs to be correct (which is only relevant for i16s). if (Scale != 1 && Scale * 8 != ExtSize) return ScalarCost; // And we need to zext (not sext) the indexes from a small enough type. if (const auto *ZExt = dyn_cast(GEP->getOperand(1))) { if (ZExt->getOperand(0)->getType()->getScalarSizeInBits() <= ExtSize) return VectorCost; } return ScalarCost; } return ScalarCost; } InstructionCost ARMTTIImpl::getArithmeticReductionCost(unsigned Opcode, VectorType *ValTy, std::optional FMF, TTI::TargetCostKind CostKind) { EVT ValVT = TLI->getValueType(DL, ValTy); int ISD = TLI->InstructionOpcodeToISD(Opcode); unsigned EltSize = ValVT.getScalarSizeInBits(); // In general floating point reductions are a series of elementwise // operations, with free extracts on each step. These are either in-order or // treewise depending on whether that is allowed by the fast math flags. if ((ISD == ISD::FADD || ISD == ISD::FMUL) && ((EltSize == 32 && ST->hasVFP2Base()) || (EltSize == 64 && ST->hasFP64()) || (EltSize == 16 && ST->hasFullFP16()))) { unsigned NumElts = cast(ValTy)->getNumElements(); unsigned VecLimit = ST->hasMVEFloatOps() ? 128 : (ST->hasNEON() ? 64 : -1); InstructionCost VecCost = 0; while (!TTI::requiresOrderedReduction(FMF) && isPowerOf2_32(NumElts) && NumElts * EltSize > VecLimit) { Type *VecTy = FixedVectorType::get(ValTy->getElementType(), NumElts / 2); VecCost += getArithmeticInstrCost(Opcode, VecTy, CostKind); NumElts /= 2; } // For fp16 we need to extract the upper lane elements. MVE can add a // VREV+FMIN/MAX to perform another vector step instead. InstructionCost ExtractCost = 0; if (!TTI::requiresOrderedReduction(FMF) && ST->hasMVEFloatOps() && ValVT.getVectorElementType() == MVT::f16 && NumElts == 8) { VecCost += ST->getMVEVectorCostFactor(CostKind) * 2; NumElts /= 2; } else if (ValVT.getVectorElementType() == MVT::f16) ExtractCost = NumElts / 2; return VecCost + ExtractCost + NumElts * getArithmeticInstrCost(Opcode, ValTy->getElementType(), CostKind); } if ((ISD == ISD::AND || ISD == ISD::OR || ISD == ISD::XOR) && (EltSize == 64 || EltSize == 32 || EltSize == 16 || EltSize == 8)) { unsigned NumElts = cast(ValTy)->getNumElements(); unsigned VecLimit = ST->hasMVEIntegerOps() ? 128 : (ST->hasNEON() ? 64 : -1); InstructionCost VecCost = 0; while (isPowerOf2_32(NumElts) && NumElts * EltSize > VecLimit) { Type *VecTy = FixedVectorType::get(ValTy->getElementType(), NumElts / 2); VecCost += getArithmeticInstrCost(Opcode, VecTy, CostKind); NumElts /= 2; } // For i16/i8, MVE will perform a VREV + VORR/VAND/VEOR for the 64bit vector // step. if (ST->hasMVEIntegerOps() && ValVT.getScalarSizeInBits() <= 16 && NumElts * EltSize == 64) { Type *VecTy = FixedVectorType::get(ValTy->getElementType(), NumElts); VecCost += ST->getMVEVectorCostFactor(CostKind) + getArithmeticInstrCost(Opcode, VecTy, CostKind); NumElts /= 2; } // From here we extract the elements and perform the and/or/xor. InstructionCost ExtractCost = NumElts; return VecCost + ExtractCost + (NumElts - 1) * getArithmeticInstrCost( Opcode, ValTy->getElementType(), CostKind); } if (!ST->hasMVEIntegerOps() || !ValVT.isSimple() || ISD != ISD::ADD || TTI::requiresOrderedReduction(FMF)) return BaseT::getArithmeticReductionCost(Opcode, ValTy, FMF, CostKind); std::pair LT = getTypeLegalizationCost(ValTy); static const CostTblEntry CostTblAdd[]{ {ISD::ADD, MVT::v16i8, 1}, {ISD::ADD, MVT::v8i16, 1}, {ISD::ADD, MVT::v4i32, 1}, }; if (const auto *Entry = CostTableLookup(CostTblAdd, ISD, LT.second)) return Entry->Cost * ST->getMVEVectorCostFactor(CostKind) * LT.first; return BaseT::getArithmeticReductionCost(Opcode, ValTy, FMF, CostKind); } InstructionCost ARMTTIImpl::getExtendedReductionCost( unsigned Opcode, bool IsUnsigned, Type *ResTy, VectorType *ValTy, FastMathFlags FMF, TTI::TargetCostKind CostKind) { EVT ValVT = TLI->getValueType(DL, ValTy); EVT ResVT = TLI->getValueType(DL, ResTy); int ISD = TLI->InstructionOpcodeToISD(Opcode); switch (ISD) { case ISD::ADD: if (ST->hasMVEIntegerOps() && ValVT.isSimple() && ResVT.isSimple()) { std::pair LT = getTypeLegalizationCost(ValTy); // The legal cases are: // VADDV u/s 8/16/32 // VADDLV u/s 32 // Codegen currently cannot always handle larger than legal vectors very // well, especially for predicated reductions where the mask needs to be // split, so restrict to 128bit or smaller input types. unsigned RevVTSize = ResVT.getSizeInBits(); if (ValVT.getSizeInBits() <= 128 && ((LT.second == MVT::v16i8 && RevVTSize <= 32) || (LT.second == MVT::v8i16 && RevVTSize <= 32) || (LT.second == MVT::v4i32 && RevVTSize <= 64))) return ST->getMVEVectorCostFactor(CostKind) * LT.first; } break; default: break; } return BaseT::getExtendedReductionCost(Opcode, IsUnsigned, ResTy, ValTy, FMF, CostKind); } InstructionCost ARMTTIImpl::getMulAccReductionCost(bool IsUnsigned, Type *ResTy, VectorType *ValTy, TTI::TargetCostKind CostKind) { EVT ValVT = TLI->getValueType(DL, ValTy); EVT ResVT = TLI->getValueType(DL, ResTy); if (ST->hasMVEIntegerOps() && ValVT.isSimple() && ResVT.isSimple()) { std::pair LT = getTypeLegalizationCost(ValTy); // The legal cases are: // VMLAV u/s 8/16/32 // VMLALV u/s 16/32 // Codegen currently cannot always handle larger than legal vectors very // well, especially for predicated reductions where the mask needs to be // split, so restrict to 128bit or smaller input types. unsigned RevVTSize = ResVT.getSizeInBits(); if (ValVT.getSizeInBits() <= 128 && ((LT.second == MVT::v16i8 && RevVTSize <= 32) || (LT.second == MVT::v8i16 && RevVTSize <= 64) || (LT.second == MVT::v4i32 && RevVTSize <= 64))) return ST->getMVEVectorCostFactor(CostKind) * LT.first; } return BaseT::getMulAccReductionCost(IsUnsigned, ResTy, ValTy, CostKind); } InstructionCost ARMTTIImpl::getMinMaxReductionCost(Intrinsic::ID IID, VectorType *Ty, FastMathFlags FMF, TTI::TargetCostKind CostKind) { EVT ValVT = TLI->getValueType(DL, Ty); // In general floating point reductions are a series of elementwise // operations, with free extracts on each step. These are either in-order or // treewise depending on whether that is allowed by the fast math flags. if ((IID == Intrinsic::minnum || IID == Intrinsic::maxnum) && ((ValVT.getVectorElementType() == MVT::f32 && ST->hasVFP2Base()) || (ValVT.getVectorElementType() == MVT::f64 && ST->hasFP64()) || (ValVT.getVectorElementType() == MVT::f16 && ST->hasFullFP16()))) { unsigned NumElts = cast(Ty)->getNumElements(); unsigned EltSize = ValVT.getScalarSizeInBits(); unsigned VecLimit = ST->hasMVEFloatOps() ? 128 : (ST->hasNEON() ? 64 : -1); InstructionCost VecCost; while (isPowerOf2_32(NumElts) && NumElts * EltSize > VecLimit) { Type *VecTy = FixedVectorType::get(Ty->getElementType(), NumElts/2); IntrinsicCostAttributes ICA(IID, VecTy, {VecTy, VecTy}, FMF); VecCost += getIntrinsicInstrCost(ICA, CostKind); NumElts /= 2; } // For fp16 we need to extract the upper lane elements. MVE can add a // VREV+FMIN/MAX to perform another vector step instead. InstructionCost ExtractCost = 0; if (ST->hasMVEFloatOps() && ValVT.getVectorElementType() == MVT::f16 && NumElts == 8) { VecCost += ST->getMVEVectorCostFactor(CostKind) * 2; NumElts /= 2; } else if (ValVT.getVectorElementType() == MVT::f16) ExtractCost = cast(Ty)->getNumElements() / 2; IntrinsicCostAttributes ICA(IID, Ty->getElementType(), {Ty->getElementType(), Ty->getElementType()}, FMF); return VecCost + ExtractCost + (NumElts - 1) * getIntrinsicInstrCost(ICA, CostKind); } if (IID == Intrinsic::smin || IID == Intrinsic::smax || IID == Intrinsic::umin || IID == Intrinsic::umax) { std::pair LT = getTypeLegalizationCost(Ty); // All costs are the same for u/s min/max. These lower to vminv, which are // given a slightly higher cost as they tend to take multiple cycles for // smaller type sizes. static const CostTblEntry CostTblAdd[]{ {ISD::SMIN, MVT::v16i8, 4}, {ISD::SMIN, MVT::v8i16, 3}, {ISD::SMIN, MVT::v4i32, 2}, }; if (const auto *Entry = CostTableLookup(CostTblAdd, ISD::SMIN, LT.second)) return Entry->Cost * ST->getMVEVectorCostFactor(CostKind) * LT.first; } return BaseT::getMinMaxReductionCost(IID, Ty, FMF, CostKind); } InstructionCost ARMTTIImpl::getIntrinsicInstrCost(const IntrinsicCostAttributes &ICA, TTI::TargetCostKind CostKind) { switch (ICA.getID()) { case Intrinsic::get_active_lane_mask: // Currently we make a somewhat optimistic assumption that // active_lane_mask's are always free. In reality it may be freely folded // into a tail predicated loop, expanded into a VCPT or expanded into a lot // of add/icmp code. We may need to improve this in the future, but being // able to detect if it is free or not involves looking at a lot of other // code. We currently assume that the vectorizer inserted these, and knew // what it was doing in adding one. if (ST->hasMVEIntegerOps()) return 0; break; case Intrinsic::sadd_sat: case Intrinsic::ssub_sat: case Intrinsic::uadd_sat: case Intrinsic::usub_sat: { if (!ST->hasMVEIntegerOps()) break; Type *VT = ICA.getReturnType(); std::pair LT = getTypeLegalizationCost(VT); if (LT.second == MVT::v4i32 || LT.second == MVT::v8i16 || LT.second == MVT::v16i8) { // This is a base cost of 1 for the vqadd, plus 3 extract shifts if we // need to extend the type, as it uses shr(qadd(shl, shl)). unsigned Instrs = LT.second.getScalarSizeInBits() == VT->getScalarSizeInBits() ? 1 : 4; return LT.first * ST->getMVEVectorCostFactor(CostKind) * Instrs; } break; } case Intrinsic::abs: case Intrinsic::smin: case Intrinsic::smax: case Intrinsic::umin: case Intrinsic::umax: { if (!ST->hasMVEIntegerOps()) break; Type *VT = ICA.getReturnType(); std::pair LT = getTypeLegalizationCost(VT); if (LT.second == MVT::v4i32 || LT.second == MVT::v8i16 || LT.second == MVT::v16i8) return LT.first * ST->getMVEVectorCostFactor(CostKind); break; } case Intrinsic::minnum: case Intrinsic::maxnum: { if (!ST->hasMVEFloatOps()) break; Type *VT = ICA.getReturnType(); std::pair LT = getTypeLegalizationCost(VT); if (LT.second == MVT::v4f32 || LT.second == MVT::v8f16) return LT.first * ST->getMVEVectorCostFactor(CostKind); break; } case Intrinsic::fptosi_sat: case Intrinsic::fptoui_sat: { if (ICA.getArgTypes().empty()) break; bool IsSigned = ICA.getID() == Intrinsic::fptosi_sat; auto LT = getTypeLegalizationCost(ICA.getArgTypes()[0]); EVT MTy = TLI->getValueType(DL, ICA.getReturnType()); // Check for the legal types, with the corect subtarget features. if ((ST->hasVFP2Base() && LT.second == MVT::f32 && MTy == MVT::i32) || (ST->hasFP64() && LT.second == MVT::f64 && MTy == MVT::i32) || (ST->hasFullFP16() && LT.second == MVT::f16 && MTy == MVT::i32)) return LT.first; // Equally for MVE vector types if (ST->hasMVEFloatOps() && (LT.second == MVT::v4f32 || LT.second == MVT::v8f16) && LT.second.getScalarSizeInBits() == MTy.getScalarSizeInBits()) return LT.first * ST->getMVEVectorCostFactor(CostKind); // Otherwise we use a legal convert followed by a min+max if (((ST->hasVFP2Base() && LT.second == MVT::f32) || (ST->hasFP64() && LT.second == MVT::f64) || (ST->hasFullFP16() && LT.second == MVT::f16) || (ST->hasMVEFloatOps() && (LT.second == MVT::v4f32 || LT.second == MVT::v8f16))) && LT.second.getScalarSizeInBits() >= MTy.getScalarSizeInBits()) { Type *LegalTy = Type::getIntNTy(ICA.getReturnType()->getContext(), LT.second.getScalarSizeInBits()); InstructionCost Cost = LT.second.isVector() ? ST->getMVEVectorCostFactor(CostKind) : 1; IntrinsicCostAttributes Attrs1(IsSigned ? Intrinsic::smin : Intrinsic::umin, LegalTy, {LegalTy, LegalTy}); Cost += getIntrinsicInstrCost(Attrs1, CostKind); IntrinsicCostAttributes Attrs2(IsSigned ? Intrinsic::smax : Intrinsic::umax, LegalTy, {LegalTy, LegalTy}); Cost += getIntrinsicInstrCost(Attrs2, CostKind); return LT.first * Cost; } break; } } return BaseT::getIntrinsicInstrCost(ICA, CostKind); } bool ARMTTIImpl::isLoweredToCall(const Function *F) { if (!F->isIntrinsic()) return BaseT::isLoweredToCall(F); // Assume all Arm-specific intrinsics map to an instruction. if (F->getName().starts_with("llvm.arm")) return false; switch (F->getIntrinsicID()) { default: break; case Intrinsic::powi: case Intrinsic::sin: case Intrinsic::cos: case Intrinsic::pow: case Intrinsic::log: case Intrinsic::log10: case Intrinsic::log2: case Intrinsic::exp: case Intrinsic::exp2: return true; case Intrinsic::sqrt: case Intrinsic::fabs: case Intrinsic::copysign: case Intrinsic::floor: case Intrinsic::ceil: case Intrinsic::trunc: case Intrinsic::rint: case Intrinsic::nearbyint: case Intrinsic::round: case Intrinsic::canonicalize: case Intrinsic::lround: case Intrinsic::llround: case Intrinsic::lrint: case Intrinsic::llrint: if (F->getReturnType()->isDoubleTy() && !ST->hasFP64()) return true; if (F->getReturnType()->isHalfTy() && !ST->hasFullFP16()) return true; // Some operations can be handled by vector instructions and assume // unsupported vectors will be expanded into supported scalar ones. // TODO Handle scalar operations properly. return !ST->hasFPARMv8Base() && !ST->hasVFP2Base(); case Intrinsic::masked_store: case Intrinsic::masked_load: case Intrinsic::masked_gather: case Intrinsic::masked_scatter: return !ST->hasMVEIntegerOps(); case Intrinsic::sadd_with_overflow: case Intrinsic::uadd_with_overflow: case Intrinsic::ssub_with_overflow: case Intrinsic::usub_with_overflow: case Intrinsic::sadd_sat: case Intrinsic::uadd_sat: case Intrinsic::ssub_sat: case Intrinsic::usub_sat: return false; } return BaseT::isLoweredToCall(F); } bool ARMTTIImpl::maybeLoweredToCall(Instruction &I) { unsigned ISD = TLI->InstructionOpcodeToISD(I.getOpcode()); EVT VT = TLI->getValueType(DL, I.getType(), true); if (TLI->getOperationAction(ISD, VT) == TargetLowering::LibCall) return true; // Check if an intrinsic will be lowered to a call and assume that any // other CallInst will generate a bl. if (auto *Call = dyn_cast(&I)) { if (auto *II = dyn_cast(Call)) { switch(II->getIntrinsicID()) { case Intrinsic::memcpy: case Intrinsic::memset: case Intrinsic::memmove: return getNumMemOps(II) == -1; default: if (const Function *F = Call->getCalledFunction()) return isLoweredToCall(F); } } return true; } // FPv5 provides conversions between integer, double-precision, // single-precision, and half-precision formats. switch (I.getOpcode()) { default: break; case Instruction::FPToSI: case Instruction::FPToUI: case Instruction::SIToFP: case Instruction::UIToFP: case Instruction::FPTrunc: case Instruction::FPExt: return !ST->hasFPARMv8Base(); } // FIXME: Unfortunately the approach of checking the Operation Action does // not catch all cases of Legalization that use library calls. Our // Legalization step categorizes some transformations into library calls as // Custom, Expand or even Legal when doing type legalization. So for now // we have to special case for instance the SDIV of 64bit integers and the // use of floating point emulation. if (VT.isInteger() && VT.getSizeInBits() >= 64) { switch (ISD) { default: break; case ISD::SDIV: case ISD::UDIV: case ISD::SREM: case ISD::UREM: case ISD::SDIVREM: case ISD::UDIVREM: return true; } } // Assume all other non-float operations are supported. if (!VT.isFloatingPoint()) return false; // We'll need a library call to handle most floats when using soft. if (TLI->useSoftFloat()) { switch (I.getOpcode()) { default: return true; case Instruction::Alloca: case Instruction::Load: case Instruction::Store: case Instruction::Select: case Instruction::PHI: return false; } } // We'll need a libcall to perform double precision operations on a single // precision only FPU. if (I.getType()->isDoubleTy() && !ST->hasFP64()) return true; // Likewise for half precision arithmetic. if (I.getType()->isHalfTy() && !ST->hasFullFP16()) return true; return false; } bool ARMTTIImpl::isHardwareLoopProfitable(Loop *L, ScalarEvolution &SE, AssumptionCache &AC, TargetLibraryInfo *LibInfo, HardwareLoopInfo &HWLoopInfo) { // Low-overhead branches are only supported in the 'low-overhead branch' // extension of v8.1-m. if (!ST->hasLOB() || DisableLowOverheadLoops) { LLVM_DEBUG(dbgs() << "ARMHWLoops: Disabled\n"); return false; } if (!SE.hasLoopInvariantBackedgeTakenCount(L)) { LLVM_DEBUG(dbgs() << "ARMHWLoops: No BETC\n"); return false; } const SCEV *BackedgeTakenCount = SE.getBackedgeTakenCount(L); if (isa(BackedgeTakenCount)) { LLVM_DEBUG(dbgs() << "ARMHWLoops: Uncomputable BETC\n"); return false; } const SCEV *TripCountSCEV = SE.getAddExpr(BackedgeTakenCount, SE.getOne(BackedgeTakenCount->getType())); // We need to store the trip count in LR, a 32-bit register. if (SE.getUnsignedRangeMax(TripCountSCEV).getBitWidth() > 32) { LLVM_DEBUG(dbgs() << "ARMHWLoops: Trip count does not fit into 32bits\n"); return false; } // Making a call will trash LR and clear LO_BRANCH_INFO, so there's little // point in generating a hardware loop if that's going to happen. auto IsHardwareLoopIntrinsic = [](Instruction &I) { if (auto *Call = dyn_cast(&I)) { switch (Call->getIntrinsicID()) { default: break; case Intrinsic::start_loop_iterations: case Intrinsic::test_start_loop_iterations: case Intrinsic::loop_decrement: case Intrinsic::loop_decrement_reg: return true; } } return false; }; // Scan the instructions to see if there's any that we know will turn into a // call or if this loop is already a low-overhead loop or will become a tail // predicated loop. bool IsTailPredLoop = false; auto ScanLoop = [&](Loop *L) { for (auto *BB : L->getBlocks()) { for (auto &I : *BB) { if (maybeLoweredToCall(I) || IsHardwareLoopIntrinsic(I) || isa(I)) { LLVM_DEBUG(dbgs() << "ARMHWLoops: Bad instruction: " << I << "\n"); return false; } if (auto *II = dyn_cast(&I)) IsTailPredLoop |= II->getIntrinsicID() == Intrinsic::get_active_lane_mask || II->getIntrinsicID() == Intrinsic::arm_mve_vctp8 || II->getIntrinsicID() == Intrinsic::arm_mve_vctp16 || II->getIntrinsicID() == Intrinsic::arm_mve_vctp32 || II->getIntrinsicID() == Intrinsic::arm_mve_vctp64; } } return true; }; // Visit inner loops. for (auto *Inner : *L) if (!ScanLoop(Inner)) return false; if (!ScanLoop(L)) return false; // TODO: Check whether the trip count calculation is expensive. If L is the // inner loop but we know it has a low trip count, calculating that trip // count (in the parent loop) may be detrimental. LLVMContext &C = L->getHeader()->getContext(); HWLoopInfo.CounterInReg = true; HWLoopInfo.IsNestingLegal = false; HWLoopInfo.PerformEntryTest = AllowWLSLoops && !IsTailPredLoop; HWLoopInfo.CountType = Type::getInt32Ty(C); HWLoopInfo.LoopDecrement = ConstantInt::get(HWLoopInfo.CountType, 1); return true; } static bool canTailPredicateInstruction(Instruction &I, int &ICmpCount) { // We don't allow icmp's, and because we only look at single block loops, // we simply count the icmps, i.e. there should only be 1 for the backedge. if (isa(&I) && ++ICmpCount > 1) return false; // FIXME: This is a workaround for poor cost modelling. Min/Max intrinsics are // not currently canonical, but soon will be. Code without them uses icmp, and // so is not tail predicated as per the condition above. In order to get the // same performance we treat min and max the same as an icmp for tailpred // purposes for the moment (we often rely on non-tailpred and higher VF's to // pick more optimial instructions like VQDMULH. They need to be recognized // directly by the vectorizer). if (auto *II = dyn_cast(&I)) if ((II->getIntrinsicID() == Intrinsic::smin || II->getIntrinsicID() == Intrinsic::smax || II->getIntrinsicID() == Intrinsic::umin || II->getIntrinsicID() == Intrinsic::umax) && ++ICmpCount > 1) return false; if (isa(&I)) return false; // We could allow extending/narrowing FP loads/stores, but codegen is // too inefficient so reject this for now. if (isa(&I) || isa(&I)) return false; // Extends have to be extending-loads if (isa(&I) || isa(&I) ) if (!I.getOperand(0)->hasOneUse() || !isa(I.getOperand(0))) return false; // Truncs have to be narrowing-stores if (isa(&I) ) if (!I.hasOneUse() || !isa(*I.user_begin())) return false; return true; } // To set up a tail-predicated loop, we need to know the total number of // elements processed by that loop. Thus, we need to determine the element // size and: // 1) it should be uniform for all operations in the vector loop, so we // e.g. don't want any widening/narrowing operations. // 2) it should be smaller than i64s because we don't have vector operations // that work on i64s. // 3) we don't want elements to be reversed or shuffled, to make sure the // tail-predication masks/predicates the right lanes. // static bool canTailPredicateLoop(Loop *L, LoopInfo *LI, ScalarEvolution &SE, const DataLayout &DL, const LoopAccessInfo *LAI) { LLVM_DEBUG(dbgs() << "Tail-predication: checking allowed instructions\n"); // If there are live-out values, it is probably a reduction. We can predicate // most reduction operations freely under MVE using a combination of // prefer-predicated-reduction-select and inloop reductions. We limit this to // floating point and integer reductions, but don't check for operators // specifically here. If the value ends up not being a reduction (and so the // vectorizer cannot tailfold the loop), we should fall back to standard // vectorization automatically. SmallVector< Instruction *, 8 > LiveOuts; LiveOuts = llvm::findDefsUsedOutsideOfLoop(L); bool ReductionsDisabled = EnableTailPredication == TailPredication::EnabledNoReductions || EnableTailPredication == TailPredication::ForceEnabledNoReductions; for (auto *I : LiveOuts) { if (!I->getType()->isIntegerTy() && !I->getType()->isFloatTy() && !I->getType()->isHalfTy()) { LLVM_DEBUG(dbgs() << "Don't tail-predicate loop with non-integer/float " "live-out value\n"); return false; } if (ReductionsDisabled) { LLVM_DEBUG(dbgs() << "Reductions not enabled\n"); return false; } } // Next, check that all instructions can be tail-predicated. PredicatedScalarEvolution PSE = LAI->getPSE(); SmallVector LoadStores; int ICmpCount = 0; for (BasicBlock *BB : L->blocks()) { for (Instruction &I : BB->instructionsWithoutDebug()) { if (isa(&I)) continue; if (!canTailPredicateInstruction(I, ICmpCount)) { LLVM_DEBUG(dbgs() << "Instruction not allowed: "; I.dump()); return false; } Type *T = I.getType(); if (T->getScalarSizeInBits() > 32) { LLVM_DEBUG(dbgs() << "Unsupported Type: "; T->dump()); return false; } if (isa(I) || isa(I)) { Value *Ptr = getLoadStorePointerOperand(&I); Type *AccessTy = getLoadStoreType(&I); int64_t NextStride = getPtrStride(PSE, AccessTy, Ptr, L).value_or(0); if (NextStride == 1) { // TODO: for now only allow consecutive strides of 1. We could support // other strides as long as it is uniform, but let's keep it simple // for now. continue; } else if (NextStride == -1 || (NextStride == 2 && MVEMaxSupportedInterleaveFactor >= 2) || (NextStride == 4 && MVEMaxSupportedInterleaveFactor >= 4)) { LLVM_DEBUG(dbgs() << "Consecutive strides of 2 found, vld2/vstr2 can't " "be tail-predicated\n."); return false; // TODO: don't tail predicate if there is a reversed load? } else if (EnableMaskedGatherScatters) { // Gather/scatters do allow loading from arbitrary strides, at // least if they are loop invariant. // TODO: Loop variant strides should in theory work, too, but // this requires further testing. const SCEV *PtrScev = PSE.getSE()->getSCEV(Ptr); if (auto AR = dyn_cast(PtrScev)) { const SCEV *Step = AR->getStepRecurrence(*PSE.getSE()); if (PSE.getSE()->isLoopInvariant(Step, L)) continue; } } LLVM_DEBUG(dbgs() << "Bad stride found, can't " "tail-predicate\n."); return false; } } } LLVM_DEBUG(dbgs() << "tail-predication: all instructions allowed!\n"); return true; } bool ARMTTIImpl::preferPredicateOverEpilogue(TailFoldingInfo *TFI) { if (!EnableTailPredication) { LLVM_DEBUG(dbgs() << "Tail-predication not enabled.\n"); return false; } // Creating a predicated vector loop is the first step for generating a // tail-predicated hardware loop, for which we need the MVE masked // load/stores instructions: if (!ST->hasMVEIntegerOps()) return false; LoopVectorizationLegality *LVL = TFI->LVL; Loop *L = LVL->getLoop(); // For now, restrict this to single block loops. if (L->getNumBlocks() > 1) { LLVM_DEBUG(dbgs() << "preferPredicateOverEpilogue: not a single block " "loop.\n"); return false; } assert(L->isInnermost() && "preferPredicateOverEpilogue: inner-loop expected"); LoopInfo *LI = LVL->getLoopInfo(); HardwareLoopInfo HWLoopInfo(L); if (!HWLoopInfo.canAnalyze(*LI)) { LLVM_DEBUG(dbgs() << "preferPredicateOverEpilogue: hardware-loop is not " "analyzable.\n"); return false; } AssumptionCache *AC = LVL->getAssumptionCache(); ScalarEvolution *SE = LVL->getScalarEvolution(); // This checks if we have the low-overhead branch architecture // extension, and if we will create a hardware-loop: if (!isHardwareLoopProfitable(L, *SE, *AC, TFI->TLI, HWLoopInfo)) { LLVM_DEBUG(dbgs() << "preferPredicateOverEpilogue: hardware-loop is not " "profitable.\n"); return false; } DominatorTree *DT = LVL->getDominatorTree(); if (!HWLoopInfo.isHardwareLoopCandidate(*SE, *LI, *DT)) { LLVM_DEBUG(dbgs() << "preferPredicateOverEpilogue: hardware-loop is not " "a candidate.\n"); return false; } return canTailPredicateLoop(L, LI, *SE, DL, LVL->getLAI()); } TailFoldingStyle ARMTTIImpl::getPreferredTailFoldingStyle(bool IVUpdateMayOverflow) const { if (!ST->hasMVEIntegerOps() || !EnableTailPredication) return TailFoldingStyle::DataWithoutLaneMask; // Intrinsic @llvm.get.active.lane.mask is supported. // It is used in the MVETailPredication pass, which requires the number of // elements processed by this vector loop to setup the tail-predicated // loop. return TailFoldingStyle::Data; } void ARMTTIImpl::getUnrollingPreferences(Loop *L, ScalarEvolution &SE, TTI::UnrollingPreferences &UP, OptimizationRemarkEmitter *ORE) { // Enable Upper bound unrolling universally, providing that we do not see an // active lane mask, which will be better kept as a loop to become tail // predicated than to be conditionally unrolled. UP.UpperBound = !ST->hasMVEIntegerOps() || !any_of(*L->getHeader(), [](Instruction &I) { return isa(I) && cast(I).getIntrinsicID() == Intrinsic::get_active_lane_mask; }); // Only currently enable these preferences for M-Class cores. if (!ST->isMClass()) return BasicTTIImplBase::getUnrollingPreferences(L, SE, UP, ORE); // Disable loop unrolling for Oz and Os. UP.OptSizeThreshold = 0; UP.PartialOptSizeThreshold = 0; if (L->getHeader()->getParent()->hasOptSize()) return; SmallVector ExitingBlocks; L->getExitingBlocks(ExitingBlocks); LLVM_DEBUG(dbgs() << "Loop has:\n" << "Blocks: " << L->getNumBlocks() << "\n" << "Exit blocks: " << ExitingBlocks.size() << "\n"); // Only allow another exit other than the latch. This acts as an early exit // as it mirrors the profitability calculation of the runtime unroller. if (ExitingBlocks.size() > 2) return; // Limit the CFG of the loop body for targets with a branch predictor. // Allowing 4 blocks permits if-then-else diamonds in the body. if (ST->hasBranchPredictor() && L->getNumBlocks() > 4) return; // Don't unroll vectorized loops, including the remainder loop if (getBooleanLoopAttribute(L, "llvm.loop.isvectorized")) return; // Scan the loop: don't unroll loops with calls as this could prevent // inlining. InstructionCost Cost = 0; for (auto *BB : L->getBlocks()) { for (auto &I : *BB) { // Don't unroll vectorised loop. MVE does not benefit from it as much as // scalar code. if (I.getType()->isVectorTy()) return; if (isa(I) || isa(I)) { if (const Function *F = cast(I).getCalledFunction()) { if (!isLoweredToCall(F)) continue; } return; } SmallVector Operands(I.operand_values()); Cost += getInstructionCost(&I, Operands, TargetTransformInfo::TCK_SizeAndLatency); } } // On v6m cores, there are very few registers available. We can easily end up // spilling and reloading more registers in an unrolled loop. Look at the // number of LCSSA phis as a rough measure of how many registers will need to // be live out of the loop, reducing the default unroll count if more than 1 // value is needed. In the long run, all of this should be being learnt by a // machine. unsigned UnrollCount = 4; if (ST->isThumb1Only()) { unsigned ExitingValues = 0; SmallVector ExitBlocks; L->getExitBlocks(ExitBlocks); for (auto *Exit : ExitBlocks) { // Count the number of LCSSA phis. Exclude values coming from GEP's as // only the last is expected to be needed for address operands. unsigned LiveOuts = count_if(Exit->phis(), [](auto &PH) { return PH.getNumOperands() != 1 || !isa(PH.getOperand(0)); }); ExitingValues = ExitingValues < LiveOuts ? LiveOuts : ExitingValues; } if (ExitingValues) UnrollCount /= ExitingValues; if (UnrollCount <= 1) return; } LLVM_DEBUG(dbgs() << "Cost of loop: " << Cost << "\n"); LLVM_DEBUG(dbgs() << "Default Runtime Unroll Count: " << UnrollCount << "\n"); UP.Partial = true; UP.Runtime = true; UP.UnrollRemainder = true; UP.DefaultUnrollRuntimeCount = UnrollCount; UP.UnrollAndJam = true; UP.UnrollAndJamInnerLoopThreshold = 60; // Force unrolling small loops can be very useful because of the branch // taken cost of the backedge. if (Cost < 12) UP.Force = true; } void ARMTTIImpl::getPeelingPreferences(Loop *L, ScalarEvolution &SE, TTI::PeelingPreferences &PP) { BaseT::getPeelingPreferences(L, SE, PP); } bool ARMTTIImpl::preferInLoopReduction(unsigned Opcode, Type *Ty, TTI::ReductionFlags Flags) const { if (!ST->hasMVEIntegerOps()) return false; unsigned ScalarBits = Ty->getScalarSizeInBits(); switch (Opcode) { case Instruction::Add: return ScalarBits <= 64; default: return false; } } bool ARMTTIImpl::preferPredicatedReductionSelect( unsigned Opcode, Type *Ty, TTI::ReductionFlags Flags) const { if (!ST->hasMVEIntegerOps()) return false; return true; } InstructionCost ARMTTIImpl::getScalingFactorCost(Type *Ty, GlobalValue *BaseGV, StackOffset BaseOffset, bool HasBaseReg, int64_t Scale, unsigned AddrSpace) const { TargetLoweringBase::AddrMode AM; AM.BaseGV = BaseGV; AM.BaseOffs = BaseOffset.getFixed(); AM.HasBaseReg = HasBaseReg; AM.Scale = Scale; AM.ScalableOffset = BaseOffset.getScalable(); if (getTLI()->isLegalAddressingMode(DL, AM, Ty, AddrSpace)) { if (ST->hasFPAO()) return AM.Scale < 0 ? 1 : 0; // positive offsets execute faster return 0; } return -1; } bool ARMTTIImpl::hasArmWideBranch(bool Thumb) const { if (Thumb) { // B.W is available in any Thumb2-supporting target, and also in every // version of Armv8-M, even Baseline which does not include the rest of // Thumb2. return ST->isThumb2() || ST->hasV8MBaselineOps(); } else { // B is available in all versions of the Arm ISA, so the only question is // whether that ISA is available at all. return ST->hasARMOps(); } }