| //===- AMDGPUTargetTransformInfo.cpp - AMDGPU specific TTI pass -----------===// |
| // |
| // 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 |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // \file |
| // This file implements a TargetTransformInfo analysis pass specific to the |
| // AMDGPU target machine. It uses the target's detailed information to provide |
| // more precise answers to certain TTI queries, while letting the target |
| // independent and default TTI implementations handle the rest. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "AMDGPUTargetTransformInfo.h" |
| #include "AMDGPUSubtarget.h" |
| #include "Utils/AMDGPUBaseInfo.h" |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/Analysis/LoopInfo.h" |
| #include "llvm/Analysis/TargetTransformInfo.h" |
| #include "llvm/Analysis/ValueTracking.h" |
| #include "llvm/CodeGen/ISDOpcodes.h" |
| #include "llvm/CodeGen/ValueTypes.h" |
| #include "llvm/IR/Argument.h" |
| #include "llvm/IR/Attributes.h" |
| #include "llvm/IR/BasicBlock.h" |
| #include "llvm/IR/CallingConv.h" |
| #include "llvm/IR/DataLayout.h" |
| #include "llvm/IR/DerivedTypes.h" |
| #include "llvm/IR/Function.h" |
| #include "llvm/IR/Instruction.h" |
| #include "llvm/IR/Instructions.h" |
| #include "llvm/IR/IntrinsicInst.h" |
| #include "llvm/IR/Module.h" |
| #include "llvm/IR/PatternMatch.h" |
| #include "llvm/IR/Type.h" |
| #include "llvm/IR/Value.h" |
| #include "llvm/MC/SubtargetFeature.h" |
| #include "llvm/Support/Casting.h" |
| #include "llvm/Support/CommandLine.h" |
| #include "llvm/Support/Debug.h" |
| #include "llvm/Support/ErrorHandling.h" |
| #include "llvm/Support/MachineValueType.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include "llvm/Target/TargetMachine.h" |
| #include <algorithm> |
| #include <cassert> |
| #include <limits> |
| #include <utility> |
| |
| using namespace llvm; |
| |
| #define DEBUG_TYPE "AMDGPUtti" |
| |
| static cl::opt<unsigned> UnrollThresholdPrivate( |
| "amdgpu-unroll-threshold-private", |
| cl::desc("Unroll threshold for AMDGPU if private memory used in a loop"), |
| cl::init(2700), cl::Hidden); |
| |
| static cl::opt<unsigned> UnrollThresholdLocal( |
| "amdgpu-unroll-threshold-local", |
| cl::desc("Unroll threshold for AMDGPU if local memory used in a loop"), |
| cl::init(1000), cl::Hidden); |
| |
| static cl::opt<unsigned> UnrollThresholdIf( |
| "amdgpu-unroll-threshold-if", |
| cl::desc("Unroll threshold increment for AMDGPU for each if statement inside loop"), |
| cl::init(150), cl::Hidden); |
| |
| static cl::opt<bool> UnrollRuntimeLocal( |
| "amdgpu-unroll-runtime-local", |
| cl::desc("Allow runtime unroll for AMDGPU if local memory used in a loop"), |
| cl::init(true), cl::Hidden); |
| |
| static cl::opt<bool> UseLegacyDA( |
| "amdgpu-use-legacy-divergence-analysis", |
| cl::desc("Enable legacy divergence analysis for AMDGPU"), |
| cl::init(false), cl::Hidden); |
| |
| static cl::opt<unsigned> UnrollMaxBlockToAnalyze( |
| "amdgpu-unroll-max-block-to-analyze", |
| cl::desc("Inner loop block size threshold to analyze in unroll for AMDGPU"), |
| cl::init(20), cl::Hidden); |
| |
| static bool dependsOnLocalPhi(const Loop *L, const Value *Cond, |
| unsigned Depth = 0) { |
| const Instruction *I = dyn_cast<Instruction>(Cond); |
| if (!I) |
| return false; |
| |
| for (const Value *V : I->operand_values()) { |
| if (!L->contains(I)) |
| continue; |
| if (const PHINode *PHI = dyn_cast<PHINode>(V)) { |
| if (llvm::none_of(L->getSubLoops(), [PHI](const Loop* SubLoop) { |
| return SubLoop->contains(PHI); })) |
| return true; |
| } else if (Depth < 10 && dependsOnLocalPhi(L, V, Depth+1)) |
| return true; |
| } |
| return false; |
| } |
| |
| void AMDGPUTTIImpl::getUnrollingPreferences(Loop *L, ScalarEvolution &SE, |
| TTI::UnrollingPreferences &UP) { |
| const Function &F = *L->getHeader()->getParent(); |
| UP.Threshold = AMDGPU::getIntegerAttribute(F, "amdgpu-unroll-threshold", 300); |
| UP.MaxCount = std::numeric_limits<unsigned>::max(); |
| UP.Partial = true; |
| |
| // TODO: Do we want runtime unrolling? |
| |
| // Maximum alloca size than can fit registers. Reserve 16 registers. |
| const unsigned MaxAlloca = (256 - 16) * 4; |
| unsigned ThresholdPrivate = UnrollThresholdPrivate; |
| unsigned ThresholdLocal = UnrollThresholdLocal; |
| unsigned MaxBoost = std::max(ThresholdPrivate, ThresholdLocal); |
| for (const BasicBlock *BB : L->getBlocks()) { |
| const DataLayout &DL = BB->getModule()->getDataLayout(); |
| unsigned LocalGEPsSeen = 0; |
| |
| if (llvm::any_of(L->getSubLoops(), [BB](const Loop* SubLoop) { |
| return SubLoop->contains(BB); })) |
| continue; // Block belongs to an inner loop. |
| |
| for (const Instruction &I : *BB) { |
| // Unroll a loop which contains an "if" statement whose condition |
| // defined by a PHI belonging to the loop. This may help to eliminate |
| // if region and potentially even PHI itself, saving on both divergence |
| // and registers used for the PHI. |
| // Add a small bonus for each of such "if" statements. |
| if (const BranchInst *Br = dyn_cast<BranchInst>(&I)) { |
| if (UP.Threshold < MaxBoost && Br->isConditional()) { |
| BasicBlock *Succ0 = Br->getSuccessor(0); |
| BasicBlock *Succ1 = Br->getSuccessor(1); |
| if ((L->contains(Succ0) && L->isLoopExiting(Succ0)) || |
| (L->contains(Succ1) && L->isLoopExiting(Succ1))) |
| continue; |
| if (dependsOnLocalPhi(L, Br->getCondition())) { |
| UP.Threshold += UnrollThresholdIf; |
| LLVM_DEBUG(dbgs() << "Set unroll threshold " << UP.Threshold |
| << " for loop:\n" |
| << *L << " due to " << *Br << '\n'); |
| if (UP.Threshold >= MaxBoost) |
| return; |
| } |
| } |
| continue; |
| } |
| |
| const GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(&I); |
| if (!GEP) |
| continue; |
| |
| unsigned AS = GEP->getAddressSpace(); |
| unsigned Threshold = 0; |
| if (AS == AMDGPUAS::PRIVATE_ADDRESS) |
| Threshold = ThresholdPrivate; |
| else if (AS == AMDGPUAS::LOCAL_ADDRESS || AS == AMDGPUAS::REGION_ADDRESS) |
| Threshold = ThresholdLocal; |
| else |
| continue; |
| |
| if (UP.Threshold >= Threshold) |
| continue; |
| |
| if (AS == AMDGPUAS::PRIVATE_ADDRESS) { |
| const Value *Ptr = GEP->getPointerOperand(); |
| const AllocaInst *Alloca = |
| dyn_cast<AllocaInst>(GetUnderlyingObject(Ptr, DL)); |
| if (!Alloca || !Alloca->isStaticAlloca()) |
| continue; |
| Type *Ty = Alloca->getAllocatedType(); |
| unsigned AllocaSize = Ty->isSized() ? DL.getTypeAllocSize(Ty) : 0; |
| if (AllocaSize > MaxAlloca) |
| continue; |
| } else if (AS == AMDGPUAS::LOCAL_ADDRESS || |
| AS == AMDGPUAS::REGION_ADDRESS) { |
| LocalGEPsSeen++; |
| // Inhibit unroll for local memory if we have seen addressing not to |
| // a variable, most likely we will be unable to combine it. |
| // Do not unroll too deep inner loops for local memory to give a chance |
| // to unroll an outer loop for a more important reason. |
| if (LocalGEPsSeen > 1 || L->getLoopDepth() > 2 || |
| (!isa<GlobalVariable>(GEP->getPointerOperand()) && |
| !isa<Argument>(GEP->getPointerOperand()))) |
| continue; |
| LLVM_DEBUG(dbgs() << "Allow unroll runtime for loop:\n" |
| << *L << " due to LDS use.\n"); |
| UP.Runtime = UnrollRuntimeLocal; |
| } |
| |
| // Check if GEP depends on a value defined by this loop itself. |
| bool HasLoopDef = false; |
| for (const Value *Op : GEP->operands()) { |
| const Instruction *Inst = dyn_cast<Instruction>(Op); |
| if (!Inst || L->isLoopInvariant(Op)) |
| continue; |
| |
| if (llvm::any_of(L->getSubLoops(), [Inst](const Loop* SubLoop) { |
| return SubLoop->contains(Inst); })) |
| continue; |
| HasLoopDef = true; |
| break; |
| } |
| if (!HasLoopDef) |
| continue; |
| |
| // We want to do whatever we can to limit the number of alloca |
| // instructions that make it through to the code generator. allocas |
| // require us to use indirect addressing, which is slow and prone to |
| // compiler bugs. If this loop does an address calculation on an |
| // alloca ptr, then we want to use a higher than normal loop unroll |
| // threshold. This will give SROA a better chance to eliminate these |
| // allocas. |
| // |
| // We also want to have more unrolling for local memory to let ds |
| // instructions with different offsets combine. |
| // |
| // Don't use the maximum allowed value here as it will make some |
| // programs way too big. |
| UP.Threshold = Threshold; |
| LLVM_DEBUG(dbgs() << "Set unroll threshold " << Threshold |
| << " for loop:\n" |
| << *L << " due to " << *GEP << '\n'); |
| if (UP.Threshold >= MaxBoost) |
| return; |
| } |
| |
| // If we got a GEP in a small BB from inner loop then increase max trip |
| // count to analyze for better estimation cost in unroll |
| if (L->empty() && BB->size() < UnrollMaxBlockToAnalyze) |
| UP.MaxIterationsCountToAnalyze = 32; |
| } |
| } |
| |
| void AMDGPUTTIImpl::getPeelingPreferences(Loop *L, ScalarEvolution &SE, |
| TTI::PeelingPreferences &PP) { |
| BaseT::getPeelingPreferences(L, SE, PP); |
| } |
| unsigned GCNTTIImpl::getHardwareNumberOfRegisters(bool Vec) const { |
| // The concept of vector registers doesn't really exist. Some packed vector |
| // operations operate on the normal 32-bit registers. |
| return MaxVGPRs; |
| } |
| |
| unsigned GCNTTIImpl::getNumberOfRegisters(bool Vec) const { |
| // This is really the number of registers to fill when vectorizing / |
| // interleaving loops, so we lie to avoid trying to use all registers. |
| return getHardwareNumberOfRegisters(Vec) >> 3; |
| } |
| |
| unsigned GCNTTIImpl::getNumberOfRegisters(unsigned RCID) const { |
| const SIRegisterInfo *TRI = ST->getRegisterInfo(); |
| const TargetRegisterClass *RC = TRI->getRegClass(RCID); |
| unsigned NumVGPRs = (TRI->getRegSizeInBits(*RC) + 31) / 32; |
| return getHardwareNumberOfRegisters(false) / NumVGPRs; |
| } |
| |
| unsigned GCNTTIImpl::getRegisterBitWidth(bool Vector) const { |
| return 32; |
| } |
| |
| unsigned GCNTTIImpl::getMinVectorRegisterBitWidth() const { |
| return 32; |
| } |
| |
| unsigned GCNTTIImpl::getLoadVectorFactor(unsigned VF, unsigned LoadSize, |
| unsigned ChainSizeInBytes, |
| VectorType *VecTy) const { |
| unsigned VecRegBitWidth = VF * LoadSize; |
| if (VecRegBitWidth > 128 && VecTy->getScalarSizeInBits() < 32) |
| // TODO: Support element-size less than 32bit? |
| return 128 / LoadSize; |
| |
| return VF; |
| } |
| |
| unsigned GCNTTIImpl::getStoreVectorFactor(unsigned VF, unsigned StoreSize, |
| unsigned ChainSizeInBytes, |
| VectorType *VecTy) const { |
| unsigned VecRegBitWidth = VF * StoreSize; |
| if (VecRegBitWidth > 128) |
| return 128 / StoreSize; |
| |
| return VF; |
| } |
| |
| unsigned GCNTTIImpl::getLoadStoreVecRegBitWidth(unsigned AddrSpace) const { |
| if (AddrSpace == AMDGPUAS::GLOBAL_ADDRESS || |
| AddrSpace == AMDGPUAS::CONSTANT_ADDRESS || |
| AddrSpace == AMDGPUAS::CONSTANT_ADDRESS_32BIT || |
| AddrSpace == AMDGPUAS::BUFFER_FAT_POINTER) { |
| return 512; |
| } |
| |
| if (AddrSpace == AMDGPUAS::PRIVATE_ADDRESS) |
| return 8 * ST->getMaxPrivateElementSize(); |
| |
| // Common to flat, global, local and region. Assume for unknown addrspace. |
| return 128; |
| } |
| |
| bool GCNTTIImpl::isLegalToVectorizeMemChain(unsigned ChainSizeInBytes, |
| Align Alignment, |
| unsigned AddrSpace) const { |
| // We allow vectorization of flat stores, even though we may need to decompose |
| // them later if they may access private memory. We don't have enough context |
| // here, and legalization can handle it. |
| if (AddrSpace == AMDGPUAS::PRIVATE_ADDRESS) { |
| return (Alignment >= 4 || ST->hasUnalignedScratchAccess()) && |
| ChainSizeInBytes <= ST->getMaxPrivateElementSize(); |
| } |
| return true; |
| } |
| |
| bool GCNTTIImpl::isLegalToVectorizeLoadChain(unsigned ChainSizeInBytes, |
| Align Alignment, |
| unsigned AddrSpace) const { |
| return isLegalToVectorizeMemChain(ChainSizeInBytes, Alignment, AddrSpace); |
| } |
| |
| bool GCNTTIImpl::isLegalToVectorizeStoreChain(unsigned ChainSizeInBytes, |
| Align Alignment, |
| unsigned AddrSpace) const { |
| return isLegalToVectorizeMemChain(ChainSizeInBytes, Alignment, AddrSpace); |
| } |
| |
| // FIXME: Really we would like to issue multiple 128-bit loads and stores per |
| // iteration. Should we report a larger size and let it legalize? |
| // |
| // FIXME: Should we use narrower types for local/region, or account for when |
| // unaligned access is legal? |
| // |
| // FIXME: This could use fine tuning and microbenchmarks. |
| Type *GCNTTIImpl::getMemcpyLoopLoweringType(LLVMContext &Context, Value *Length, |
| unsigned SrcAddrSpace, |
| unsigned DestAddrSpace, |
| unsigned SrcAlign, |
| unsigned DestAlign) const { |
| unsigned MinAlign = std::min(SrcAlign, DestAlign); |
| |
| // A (multi-)dword access at an address == 2 (mod 4) will be decomposed by the |
| // hardware into byte accesses. If you assume all alignments are equally |
| // probable, it's more efficient on average to use short accesses for this |
| // case. |
| if (MinAlign == 2) |
| return Type::getInt16Ty(Context); |
| |
| // Not all subtargets have 128-bit DS instructions, and we currently don't |
| // form them by default. |
| if (SrcAddrSpace == AMDGPUAS::LOCAL_ADDRESS || |
| SrcAddrSpace == AMDGPUAS::REGION_ADDRESS || |
| DestAddrSpace == AMDGPUAS::LOCAL_ADDRESS || |
| DestAddrSpace == AMDGPUAS::REGION_ADDRESS) { |
| return FixedVectorType::get(Type::getInt32Ty(Context), 2); |
| } |
| |
| // Global memory works best with 16-byte accesses. Private memory will also |
| // hit this, although they'll be decomposed. |
| return FixedVectorType::get(Type::getInt32Ty(Context), 4); |
| } |
| |
| void GCNTTIImpl::getMemcpyLoopResidualLoweringType( |
| SmallVectorImpl<Type *> &OpsOut, LLVMContext &Context, |
| unsigned RemainingBytes, unsigned SrcAddrSpace, unsigned DestAddrSpace, |
| unsigned SrcAlign, unsigned DestAlign) const { |
| assert(RemainingBytes < 16); |
| |
| unsigned MinAlign = std::min(SrcAlign, DestAlign); |
| |
| if (MinAlign != 2) { |
| Type *I64Ty = Type::getInt64Ty(Context); |
| while (RemainingBytes >= 8) { |
| OpsOut.push_back(I64Ty); |
| RemainingBytes -= 8; |
| } |
| |
| Type *I32Ty = Type::getInt32Ty(Context); |
| while (RemainingBytes >= 4) { |
| OpsOut.push_back(I32Ty); |
| RemainingBytes -= 4; |
| } |
| } |
| |
| Type *I16Ty = Type::getInt16Ty(Context); |
| while (RemainingBytes >= 2) { |
| OpsOut.push_back(I16Ty); |
| RemainingBytes -= 2; |
| } |
| |
| Type *I8Ty = Type::getInt8Ty(Context); |
| while (RemainingBytes) { |
| OpsOut.push_back(I8Ty); |
| --RemainingBytes; |
| } |
| } |
| |
| unsigned GCNTTIImpl::getMaxInterleaveFactor(unsigned VF) { |
| // Disable unrolling if the loop is not vectorized. |
| // TODO: Enable this again. |
| if (VF == 1) |
| return 1; |
| |
| return 8; |
| } |
| |
| bool GCNTTIImpl::getTgtMemIntrinsic(IntrinsicInst *Inst, |
| MemIntrinsicInfo &Info) const { |
| switch (Inst->getIntrinsicID()) { |
| case Intrinsic::amdgcn_atomic_inc: |
| case Intrinsic::amdgcn_atomic_dec: |
| case Intrinsic::amdgcn_ds_ordered_add: |
| case Intrinsic::amdgcn_ds_ordered_swap: |
| case Intrinsic::amdgcn_ds_fadd: |
| case Intrinsic::amdgcn_ds_fmin: |
| case Intrinsic::amdgcn_ds_fmax: { |
| auto *Ordering = dyn_cast<ConstantInt>(Inst->getArgOperand(2)); |
| auto *Volatile = dyn_cast<ConstantInt>(Inst->getArgOperand(4)); |
| if (!Ordering || !Volatile) |
| return false; // Invalid. |
| |
| unsigned OrderingVal = Ordering->getZExtValue(); |
| if (OrderingVal > static_cast<unsigned>(AtomicOrdering::SequentiallyConsistent)) |
| return false; |
| |
| Info.PtrVal = Inst->getArgOperand(0); |
| Info.Ordering = static_cast<AtomicOrdering>(OrderingVal); |
| Info.ReadMem = true; |
| Info.WriteMem = true; |
| Info.IsVolatile = !Volatile->isNullValue(); |
| return true; |
| } |
| default: |
| return false; |
| } |
| } |
| |
| int GCNTTIImpl::getArithmeticInstrCost(unsigned Opcode, Type *Ty, |
| TTI::TargetCostKind CostKind, |
| TTI::OperandValueKind Opd1Info, |
| TTI::OperandValueKind Opd2Info, |
| TTI::OperandValueProperties Opd1PropInfo, |
| TTI::OperandValueProperties Opd2PropInfo, |
| ArrayRef<const Value *> Args, |
| const Instruction *CxtI) { |
| EVT OrigTy = TLI->getValueType(DL, Ty); |
| if (!OrigTy.isSimple()) { |
| // FIXME: We're having to query the throughput cost so that the basic |
| // implementation tries to generate legalize and scalarization costs. Maybe |
| // we could hoist the scalarization code here? |
| return BaseT::getArithmeticInstrCost(Opcode, Ty, TTI::TCK_RecipThroughput, |
| Opd1Info, Opd2Info, |
| Opd1PropInfo, Opd2PropInfo); |
| } |
| |
| // Legalize the type. |
| std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, Ty); |
| int ISD = TLI->InstructionOpcodeToISD(Opcode); |
| |
| // Because we don't have any legal vector operations, but the legal types, we |
| // need to account for split vectors. |
| unsigned NElts = LT.second.isVector() ? |
| LT.second.getVectorNumElements() : 1; |
| |
| MVT::SimpleValueType SLT = LT.second.getScalarType().SimpleTy; |
| |
| switch (ISD) { |
| case ISD::SHL: |
| case ISD::SRL: |
| case ISD::SRA: |
| if (SLT == MVT::i64) |
| return get64BitInstrCost() * LT.first * NElts; |
| |
| if (ST->has16BitInsts() && SLT == MVT::i16) |
| NElts = (NElts + 1) / 2; |
| |
| // i32 |
| return getFullRateInstrCost() * LT.first * NElts; |
| case ISD::ADD: |
| case ISD::SUB: |
| case ISD::AND: |
| case ISD::OR: |
| case ISD::XOR: |
| if (SLT == MVT::i64) { |
| // and, or and xor are typically split into 2 VALU instructions. |
| return 2 * getFullRateInstrCost() * LT.first * NElts; |
| } |
| |
| if (ST->has16BitInsts() && SLT == MVT::i16) |
| NElts = (NElts + 1) / 2; |
| |
| return LT.first * NElts * getFullRateInstrCost(); |
| case ISD::MUL: { |
| const int QuarterRateCost = getQuarterRateInstrCost(); |
| if (SLT == MVT::i64) { |
| const int FullRateCost = getFullRateInstrCost(); |
| return (4 * QuarterRateCost + (2 * 2) * FullRateCost) * LT.first * NElts; |
| } |
| |
| if (ST->has16BitInsts() && SLT == MVT::i16) |
| NElts = (NElts + 1) / 2; |
| |
| // i32 |
| return QuarterRateCost * NElts * LT.first; |
| } |
| case ISD::FADD: |
| case ISD::FSUB: |
| case ISD::FMUL: |
| if (SLT == MVT::f64) |
| return LT.first * NElts * get64BitInstrCost(); |
| |
| if (ST->has16BitInsts() && SLT == MVT::f16) |
| NElts = (NElts + 1) / 2; |
| |
| if (SLT == MVT::f32 || SLT == MVT::f16) |
| return LT.first * NElts * getFullRateInstrCost(); |
| break; |
| case ISD::FDIV: |
| case ISD::FREM: |
| // FIXME: frem should be handled separately. The fdiv in it is most of it, |
| // but the current lowering is also not entirely correct. |
| if (SLT == MVT::f64) { |
| int Cost = 4 * get64BitInstrCost() + 7 * getQuarterRateInstrCost(); |
| // Add cost of workaround. |
| if (!ST->hasUsableDivScaleConditionOutput()) |
| Cost += 3 * getFullRateInstrCost(); |
| |
| return LT.first * Cost * NElts; |
| } |
| |
| if (!Args.empty() && match(Args[0], PatternMatch::m_FPOne())) { |
| // TODO: This is more complicated, unsafe flags etc. |
| if ((SLT == MVT::f32 && !HasFP32Denormals) || |
| (SLT == MVT::f16 && ST->has16BitInsts())) { |
| return LT.first * getQuarterRateInstrCost() * NElts; |
| } |
| } |
| |
| if (SLT == MVT::f16 && ST->has16BitInsts()) { |
| // 2 x v_cvt_f32_f16 |
| // f32 rcp |
| // f32 fmul |
| // v_cvt_f16_f32 |
| // f16 div_fixup |
| int Cost = 4 * getFullRateInstrCost() + 2 * getQuarterRateInstrCost(); |
| return LT.first * Cost * NElts; |
| } |
| |
| if (SLT == MVT::f32 || SLT == MVT::f16) { |
| int Cost = 7 * getFullRateInstrCost() + 1 * getQuarterRateInstrCost(); |
| |
| if (!HasFP32Denormals) { |
| // FP mode switches. |
| Cost += 2 * getFullRateInstrCost(); |
| } |
| |
| return LT.first * NElts * Cost; |
| } |
| break; |
| case ISD::FNEG: |
| // Use the backend' estimation. If fneg is not free each element will cost |
| // one additional instruction. |
| return TLI->isFNegFree(SLT) ? 0 : NElts; |
| default: |
| break; |
| } |
| |
| return BaseT::getArithmeticInstrCost(Opcode, Ty, CostKind, Opd1Info, |
| Opd2Info, |
| Opd1PropInfo, Opd2PropInfo); |
| } |
| |
| // Return true if there's a potential benefit from using v2f16 instructions for |
| // an intrinsic, even if it requires nontrivial legalization. |
| static bool intrinsicHasPackedVectorBenefit(Intrinsic::ID ID) { |
| switch (ID) { |
| case Intrinsic::fma: // TODO: fmuladd |
| // There's a small benefit to using vector ops in the legalized code. |
| case Intrinsic::round: |
| return true; |
| default: |
| return false; |
| } |
| } |
| |
| int GCNTTIImpl::getIntrinsicInstrCost(const IntrinsicCostAttributes &ICA, |
| TTI::TargetCostKind CostKind) { |
| if (ICA.getID() == Intrinsic::fabs) |
| return 0; |
| |
| if (!intrinsicHasPackedVectorBenefit(ICA.getID())) |
| return BaseT::getIntrinsicInstrCost(ICA, CostKind); |
| |
| Type *RetTy = ICA.getReturnType(); |
| EVT OrigTy = TLI->getValueType(DL, RetTy); |
| if (!OrigTy.isSimple()) { |
| return BaseT::getIntrinsicInstrCost(ICA, CostKind); |
| } |
| |
| // Legalize the type. |
| std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, RetTy); |
| |
| unsigned NElts = LT.second.isVector() ? |
| LT.second.getVectorNumElements() : 1; |
| |
| MVT::SimpleValueType SLT = LT.second.getScalarType().SimpleTy; |
| |
| if (SLT == MVT::f64) |
| return LT.first * NElts * get64BitInstrCost(); |
| |
| if (ST->has16BitInsts() && SLT == MVT::f16) |
| NElts = (NElts + 1) / 2; |
| |
| // TODO: Get more refined intrinsic costs? |
| unsigned InstRate = getQuarterRateInstrCost(); |
| if (ICA.getID() == Intrinsic::fma) { |
| InstRate = ST->hasFastFMAF32() ? getHalfRateInstrCost() |
| : getQuarterRateInstrCost(); |
| } |
| |
| return LT.first * NElts * InstRate; |
| } |
| |
| unsigned GCNTTIImpl::getCFInstrCost(unsigned Opcode, |
| TTI::TargetCostKind CostKind) { |
| if (CostKind == TTI::TCK_CodeSize || CostKind == TTI::TCK_SizeAndLatency) |
| return Opcode == Instruction::PHI ? 0 : 1; |
| |
| // XXX - For some reason this isn't called for switch. |
| switch (Opcode) { |
| case Instruction::Br: |
| case Instruction::Ret: |
| return 10; |
| default: |
| return BaseT::getCFInstrCost(Opcode, CostKind); |
| } |
| } |
| |
| int GCNTTIImpl::getArithmeticReductionCost(unsigned Opcode, VectorType *Ty, |
| bool IsPairwise, |
| TTI::TargetCostKind CostKind) { |
| EVT OrigTy = TLI->getValueType(DL, Ty); |
| |
| // Computes cost on targets that have packed math instructions(which support |
| // 16-bit types only). |
| if (IsPairwise || |
| !ST->hasVOP3PInsts() || |
| OrigTy.getScalarSizeInBits() != 16) |
| return BaseT::getArithmeticReductionCost(Opcode, Ty, IsPairwise, CostKind); |
| |
| std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, Ty); |
| return LT.first * getFullRateInstrCost(); |
| } |
| |
| int GCNTTIImpl::getMinMaxReductionCost(VectorType *Ty, VectorType *CondTy, |
| bool IsPairwise, bool IsUnsigned, |
| TTI::TargetCostKind CostKind) { |
| EVT OrigTy = TLI->getValueType(DL, Ty); |
| |
| // Computes cost on targets that have packed math instructions(which support |
| // 16-bit types only). |
| if (IsPairwise || |
| !ST->hasVOP3PInsts() || |
| OrigTy.getScalarSizeInBits() != 16) |
| return BaseT::getMinMaxReductionCost(Ty, CondTy, IsPairwise, IsUnsigned, |
| CostKind); |
| |
| std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, Ty); |
| return LT.first * getHalfRateInstrCost(); |
| } |
| |
| int GCNTTIImpl::getVectorInstrCost(unsigned Opcode, Type *ValTy, |
| unsigned Index) { |
| switch (Opcode) { |
| case Instruction::ExtractElement: |
| case Instruction::InsertElement: { |
| unsigned EltSize |
| = DL.getTypeSizeInBits(cast<VectorType>(ValTy)->getElementType()); |
| if (EltSize < 32) { |
| if (EltSize == 16 && Index == 0 && ST->has16BitInsts()) |
| return 0; |
| return BaseT::getVectorInstrCost(Opcode, ValTy, Index); |
| } |
| |
| // Extracts are just reads of a subregister, so are free. Inserts are |
| // considered free because we don't want to have any cost for scalarizing |
| // operations, and we don't have to copy into a different register class. |
| |
| // Dynamic indexing isn't free and is best avoided. |
| return Index == ~0u ? 2 : 0; |
| } |
| default: |
| return BaseT::getVectorInstrCost(Opcode, ValTy, Index); |
| } |
| } |
| |
| static bool isArgPassedInSGPR(const Argument *A) { |
| const Function *F = A->getParent(); |
| |
| // Arguments to compute shaders are never a source of divergence. |
| CallingConv::ID CC = F->getCallingConv(); |
| switch (CC) { |
| case CallingConv::AMDGPU_KERNEL: |
| case CallingConv::SPIR_KERNEL: |
| return true; |
| case CallingConv::AMDGPU_VS: |
| case CallingConv::AMDGPU_LS: |
| case CallingConv::AMDGPU_HS: |
| case CallingConv::AMDGPU_ES: |
| case CallingConv::AMDGPU_GS: |
| case CallingConv::AMDGPU_PS: |
| case CallingConv::AMDGPU_CS: |
| // For non-compute shaders, SGPR inputs are marked with either inreg or byval. |
| // Everything else is in VGPRs. |
| return F->getAttributes().hasParamAttribute(A->getArgNo(), Attribute::InReg) || |
| F->getAttributes().hasParamAttribute(A->getArgNo(), Attribute::ByVal); |
| default: |
| // TODO: Should calls support inreg for SGPR inputs? |
| return false; |
| } |
| } |
| |
| /// Analyze if the results of inline asm are divergent. If \p Indices is empty, |
| /// this is analyzing the collective result of all output registers. Otherwise, |
| /// this is only querying a specific result index if this returns multiple |
| /// registers in a struct. |
| bool GCNTTIImpl::isInlineAsmSourceOfDivergence( |
| const CallInst *CI, ArrayRef<unsigned> Indices) const { |
| // TODO: Handle complex extract indices |
| if (Indices.size() > 1) |
| return true; |
| |
| const DataLayout &DL = CI->getModule()->getDataLayout(); |
| const SIRegisterInfo *TRI = ST->getRegisterInfo(); |
| TargetLowering::AsmOperandInfoVector TargetConstraints = |
| TLI->ParseConstraints(DL, ST->getRegisterInfo(), *CI); |
| |
| const int TargetOutputIdx = Indices.empty() ? -1 : Indices[0]; |
| |
| int OutputIdx = 0; |
| for (auto &TC : TargetConstraints) { |
| if (TC.Type != InlineAsm::isOutput) |
| continue; |
| |
| // Skip outputs we don't care about. |
| if (TargetOutputIdx != -1 && TargetOutputIdx != OutputIdx++) |
| continue; |
| |
| TLI->ComputeConstraintToUse(TC, SDValue()); |
| |
| Register AssignedReg; |
| const TargetRegisterClass *RC; |
| std::tie(AssignedReg, RC) = TLI->getRegForInlineAsmConstraint( |
| TRI, TC.ConstraintCode, TC.ConstraintVT); |
| if (AssignedReg) { |
| // FIXME: This is a workaround for getRegForInlineAsmConstraint |
| // returning VS_32 |
| RC = TRI->getPhysRegClass(AssignedReg); |
| } |
| |
| // For AGPR constraints null is returned on subtargets without AGPRs, so |
| // assume divergent for null. |
| if (!RC || !TRI->isSGPRClass(RC)) |
| return true; |
| } |
| |
| return false; |
| } |
| |
| /// \returns true if the new GPU divergence analysis is enabled. |
| bool GCNTTIImpl::useGPUDivergenceAnalysis() const { |
| return !UseLegacyDA; |
| } |
| |
| /// \returns true if the result of the value could potentially be |
| /// different across workitems in a wavefront. |
| bool GCNTTIImpl::isSourceOfDivergence(const Value *V) const { |
| if (const Argument *A = dyn_cast<Argument>(V)) |
| return !isArgPassedInSGPR(A); |
| |
| // Loads from the private and flat address spaces are divergent, because |
| // threads can execute the load instruction with the same inputs and get |
| // different results. |
| // |
| // All other loads are not divergent, because if threads issue loads with the |
| // same arguments, they will always get the same result. |
| if (const LoadInst *Load = dyn_cast<LoadInst>(V)) |
| return Load->getPointerAddressSpace() == AMDGPUAS::PRIVATE_ADDRESS || |
| Load->getPointerAddressSpace() == AMDGPUAS::FLAT_ADDRESS; |
| |
| // Atomics are divergent because they are executed sequentially: when an |
| // atomic operation refers to the same address in each thread, then each |
| // thread after the first sees the value written by the previous thread as |
| // original value. |
| if (isa<AtomicRMWInst>(V) || isa<AtomicCmpXchgInst>(V)) |
| return true; |
| |
| if (const IntrinsicInst *Intrinsic = dyn_cast<IntrinsicInst>(V)) |
| return AMDGPU::isIntrinsicSourceOfDivergence(Intrinsic->getIntrinsicID()); |
| |
| // Assume all function calls are a source of divergence. |
| if (const CallInst *CI = dyn_cast<CallInst>(V)) { |
| if (CI->isInlineAsm()) |
| return isInlineAsmSourceOfDivergence(CI); |
| return true; |
| } |
| |
| // Assume all function calls are a source of divergence. |
| if (isa<InvokeInst>(V)) |
| return true; |
| |
| return false; |
| } |
| |
| bool GCNTTIImpl::isAlwaysUniform(const Value *V) const { |
| if (const IntrinsicInst *Intrinsic = dyn_cast<IntrinsicInst>(V)) { |
| switch (Intrinsic->getIntrinsicID()) { |
| default: |
| return false; |
| case Intrinsic::amdgcn_readfirstlane: |
| case Intrinsic::amdgcn_readlane: |
| case Intrinsic::amdgcn_icmp: |
| case Intrinsic::amdgcn_fcmp: |
| case Intrinsic::amdgcn_ballot: |
| case Intrinsic::amdgcn_if_break: |
| return true; |
| } |
| } |
| |
| if (const CallInst *CI = dyn_cast<CallInst>(V)) { |
| if (CI->isInlineAsm()) |
| return !isInlineAsmSourceOfDivergence(CI); |
| return false; |
| } |
| |
| const ExtractValueInst *ExtValue = dyn_cast<ExtractValueInst>(V); |
| if (!ExtValue) |
| return false; |
| |
| const CallInst *CI = dyn_cast<CallInst>(ExtValue->getOperand(0)); |
| if (!CI) |
| return false; |
| |
| if (const IntrinsicInst *Intrinsic = dyn_cast<IntrinsicInst>(CI)) { |
| switch (Intrinsic->getIntrinsicID()) { |
| default: |
| return false; |
| case Intrinsic::amdgcn_if: |
| case Intrinsic::amdgcn_else: { |
| ArrayRef<unsigned> Indices = ExtValue->getIndices(); |
| return Indices.size() == 1 && Indices[0] == 1; |
| } |
| } |
| } |
| |
| // If we have inline asm returning mixed SGPR and VGPR results, we inferred |
| // divergent for the overall struct return. We need to override it in the |
| // case we're extracting an SGPR component here. |
| if (CI->isInlineAsm()) |
| return !isInlineAsmSourceOfDivergence(CI, ExtValue->getIndices()); |
| |
| return false; |
| } |
| |
| bool GCNTTIImpl::collectFlatAddressOperands(SmallVectorImpl<int> &OpIndexes, |
| Intrinsic::ID IID) const { |
| switch (IID) { |
| case Intrinsic::amdgcn_atomic_inc: |
| case Intrinsic::amdgcn_atomic_dec: |
| case Intrinsic::amdgcn_ds_fadd: |
| case Intrinsic::amdgcn_ds_fmin: |
| case Intrinsic::amdgcn_ds_fmax: |
| case Intrinsic::amdgcn_is_shared: |
| case Intrinsic::amdgcn_is_private: |
| OpIndexes.push_back(0); |
| return true; |
| default: |
| return false; |
| } |
| } |
| |
| Value *GCNTTIImpl::rewriteIntrinsicWithAddressSpace(IntrinsicInst *II, |
| Value *OldV, |
| Value *NewV) const { |
| auto IntrID = II->getIntrinsicID(); |
| switch (IntrID) { |
| case Intrinsic::amdgcn_atomic_inc: |
| case Intrinsic::amdgcn_atomic_dec: |
| case Intrinsic::amdgcn_ds_fadd: |
| case Intrinsic::amdgcn_ds_fmin: |
| case Intrinsic::amdgcn_ds_fmax: { |
| const ConstantInt *IsVolatile = cast<ConstantInt>(II->getArgOperand(4)); |
| if (!IsVolatile->isZero()) |
| return nullptr; |
| Module *M = II->getParent()->getParent()->getParent(); |
| Type *DestTy = II->getType(); |
| Type *SrcTy = NewV->getType(); |
| Function *NewDecl = |
| Intrinsic::getDeclaration(M, II->getIntrinsicID(), {DestTy, SrcTy}); |
| II->setArgOperand(0, NewV); |
| II->setCalledFunction(NewDecl); |
| return II; |
| } |
| case Intrinsic::amdgcn_is_shared: |
| case Intrinsic::amdgcn_is_private: { |
| unsigned TrueAS = IntrID == Intrinsic::amdgcn_is_shared ? |
| AMDGPUAS::LOCAL_ADDRESS : AMDGPUAS::PRIVATE_ADDRESS; |
| unsigned NewAS = NewV->getType()->getPointerAddressSpace(); |
| LLVMContext &Ctx = NewV->getType()->getContext(); |
| ConstantInt *NewVal = (TrueAS == NewAS) ? |
| ConstantInt::getTrue(Ctx) : ConstantInt::getFalse(Ctx); |
| return NewVal; |
| } |
| case Intrinsic::ptrmask: { |
| unsigned OldAS = OldV->getType()->getPointerAddressSpace(); |
| unsigned NewAS = NewV->getType()->getPointerAddressSpace(); |
| Value *MaskOp = II->getArgOperand(1); |
| Type *MaskTy = MaskOp->getType(); |
| |
| bool DoTruncate = false; |
| if (!getTLI()->isNoopAddrSpaceCast(OldAS, NewAS)) { |
| // All valid 64-bit to 32-bit casts work by chopping off the high |
| // bits. Any masking only clearing the low bits will also apply in the new |
| // address space. |
| if (DL.getPointerSizeInBits(OldAS) != 64 || |
| DL.getPointerSizeInBits(NewAS) != 32) |
| return nullptr; |
| |
| // TODO: Do we need to thread more context in here? |
| KnownBits Known = computeKnownBits(MaskOp, DL, 0, nullptr, II); |
| if (Known.countMinLeadingOnes() < 32) |
| return nullptr; |
| |
| DoTruncate = true; |
| } |
| |
| IRBuilder<> B(II); |
| if (DoTruncate) { |
| MaskTy = B.getInt32Ty(); |
| MaskOp = B.CreateTrunc(MaskOp, MaskTy); |
| } |
| |
| return B.CreateIntrinsic(Intrinsic::ptrmask, {NewV->getType(), MaskTy}, |
| {NewV, MaskOp}); |
| } |
| default: |
| return nullptr; |
| } |
| } |
| |
| unsigned GCNTTIImpl::getShuffleCost(TTI::ShuffleKind Kind, VectorType *VT, |
| int Index, VectorType *SubTp) { |
| if (ST->hasVOP3PInsts()) { |
| if (cast<FixedVectorType>(VT)->getNumElements() == 2 && |
| DL.getTypeSizeInBits(VT->getElementType()) == 16) { |
| // With op_sel VOP3P instructions freely can access the low half or high |
| // half of a register, so any swizzle is free. |
| |
| switch (Kind) { |
| case TTI::SK_Broadcast: |
| case TTI::SK_Reverse: |
| case TTI::SK_PermuteSingleSrc: |
| return 0; |
| default: |
| break; |
| } |
| } |
| } |
| |
| return BaseT::getShuffleCost(Kind, VT, Index, SubTp); |
| } |
| |
| bool GCNTTIImpl::areInlineCompatible(const Function *Caller, |
| const Function *Callee) const { |
| const TargetMachine &TM = getTLI()->getTargetMachine(); |
| const GCNSubtarget *CallerST |
| = static_cast<const GCNSubtarget *>(TM.getSubtargetImpl(*Caller)); |
| const GCNSubtarget *CalleeST |
| = static_cast<const GCNSubtarget *>(TM.getSubtargetImpl(*Callee)); |
| |
| const FeatureBitset &CallerBits = CallerST->getFeatureBits(); |
| const FeatureBitset &CalleeBits = CalleeST->getFeatureBits(); |
| |
| FeatureBitset RealCallerBits = CallerBits & ~InlineFeatureIgnoreList; |
| FeatureBitset RealCalleeBits = CalleeBits & ~InlineFeatureIgnoreList; |
| if ((RealCallerBits & RealCalleeBits) != RealCalleeBits) |
| return false; |
| |
| // FIXME: dx10_clamp can just take the caller setting, but there seems to be |
| // no way to support merge for backend defined attributes. |
| AMDGPU::SIModeRegisterDefaults CallerMode(*Caller); |
| AMDGPU::SIModeRegisterDefaults CalleeMode(*Callee); |
| return CallerMode.isInlineCompatible(CalleeMode); |
| } |
| |
| void GCNTTIImpl::getUnrollingPreferences(Loop *L, ScalarEvolution &SE, |
| TTI::UnrollingPreferences &UP) { |
| CommonTTI.getUnrollingPreferences(L, SE, UP); |
| } |
| |
| void GCNTTIImpl::getPeelingPreferences(Loop *L, ScalarEvolution &SE, |
| TTI::PeelingPreferences &PP) { |
| CommonTTI.getPeelingPreferences(L, SE, PP); |
| } |
| |
| unsigned R600TTIImpl::getHardwareNumberOfRegisters(bool Vec) const { |
| return 4 * 128; // XXX - 4 channels. Should these count as vector instead? |
| } |
| |
| unsigned R600TTIImpl::getNumberOfRegisters(bool Vec) const { |
| return getHardwareNumberOfRegisters(Vec); |
| } |
| |
| unsigned R600TTIImpl::getRegisterBitWidth(bool Vector) const { |
| return 32; |
| } |
| |
| unsigned R600TTIImpl::getMinVectorRegisterBitWidth() const { |
| return 32; |
| } |
| |
| unsigned R600TTIImpl::getLoadStoreVecRegBitWidth(unsigned AddrSpace) const { |
| if (AddrSpace == AMDGPUAS::GLOBAL_ADDRESS || |
| AddrSpace == AMDGPUAS::CONSTANT_ADDRESS) |
| return 128; |
| if (AddrSpace == AMDGPUAS::LOCAL_ADDRESS || |
| AddrSpace == AMDGPUAS::REGION_ADDRESS) |
| return 64; |
| if (AddrSpace == AMDGPUAS::PRIVATE_ADDRESS) |
| return 32; |
| |
| if ((AddrSpace == AMDGPUAS::PARAM_D_ADDRESS || |
| AddrSpace == AMDGPUAS::PARAM_I_ADDRESS || |
| (AddrSpace >= AMDGPUAS::CONSTANT_BUFFER_0 && |
| AddrSpace <= AMDGPUAS::CONSTANT_BUFFER_15))) |
| return 128; |
| llvm_unreachable("unhandled address space"); |
| } |
| |
| bool R600TTIImpl::isLegalToVectorizeMemChain(unsigned ChainSizeInBytes, |
| Align Alignment, |
| unsigned AddrSpace) const { |
| // We allow vectorization of flat stores, even though we may need to decompose |
| // them later if they may access private memory. We don't have enough context |
| // here, and legalization can handle it. |
| return (AddrSpace != AMDGPUAS::PRIVATE_ADDRESS); |
| } |
| |
| bool R600TTIImpl::isLegalToVectorizeLoadChain(unsigned ChainSizeInBytes, |
| Align Alignment, |
| unsigned AddrSpace) const { |
| return isLegalToVectorizeMemChain(ChainSizeInBytes, Alignment, AddrSpace); |
| } |
| |
| bool R600TTIImpl::isLegalToVectorizeStoreChain(unsigned ChainSizeInBytes, |
| Align Alignment, |
| unsigned AddrSpace) const { |
| return isLegalToVectorizeMemChain(ChainSizeInBytes, Alignment, AddrSpace); |
| } |
| |
| unsigned R600TTIImpl::getMaxInterleaveFactor(unsigned VF) { |
| // Disable unrolling if the loop is not vectorized. |
| // TODO: Enable this again. |
| if (VF == 1) |
| return 1; |
| |
| return 8; |
| } |
| |
| unsigned R600TTIImpl::getCFInstrCost(unsigned Opcode, |
| TTI::TargetCostKind CostKind) { |
| if (CostKind == TTI::TCK_CodeSize || CostKind == TTI::TCK_SizeAndLatency) |
| return Opcode == Instruction::PHI ? 0 : 1; |
| |
| // XXX - For some reason this isn't called for switch. |
| switch (Opcode) { |
| case Instruction::Br: |
| case Instruction::Ret: |
| return 10; |
| default: |
| return BaseT::getCFInstrCost(Opcode, CostKind); |
| } |
| } |
| |
| int R600TTIImpl::getVectorInstrCost(unsigned Opcode, Type *ValTy, |
| unsigned Index) { |
| switch (Opcode) { |
| case Instruction::ExtractElement: |
| case Instruction::InsertElement: { |
| unsigned EltSize |
| = DL.getTypeSizeInBits(cast<VectorType>(ValTy)->getElementType()); |
| if (EltSize < 32) { |
| return BaseT::getVectorInstrCost(Opcode, ValTy, Index); |
| } |
| |
| // Extracts are just reads of a subregister, so are free. Inserts are |
| // considered free because we don't want to have any cost for scalarizing |
| // operations, and we don't have to copy into a different register class. |
| |
| // Dynamic indexing isn't free and is best avoided. |
| return Index == ~0u ? 2 : 0; |
| } |
| default: |
| return BaseT::getVectorInstrCost(Opcode, ValTy, Index); |
| } |
| } |
| |
| void R600TTIImpl::getUnrollingPreferences(Loop *L, ScalarEvolution &SE, |
| TTI::UnrollingPreferences &UP) { |
| CommonTTI.getUnrollingPreferences(L, SE, UP); |
| } |
| |
| void R600TTIImpl::getPeelingPreferences(Loop *L, ScalarEvolution &SE, |
| TTI::PeelingPreferences &PP) { |
| CommonTTI.getPeelingPreferences(L, SE, PP); |
| } |
