//===-- AArch64TargetTransformInfo.cpp - AArch64 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 "AArch64ExpandImm.h"
#include "AArch64TargetTransformInfo.h"
#include "MCTargetDesc/AArch64AddressingModes.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/CodeGen/BasicTTIImpl.h"
#include "llvm/CodeGen/CostTable.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/IntrinsicsAArch64.h"
#include "llvm/Support/Debug.h"
#include <algorithm>
using namespace llvm;
#define DEBUG_TYPE "aarch64tti"
static cl::opt<bool> EnableFalkorHWPFUnrollFix("enable-falkor-hwpf-unroll-fix",
cl::init(true), cl::Hidden);
bool AArch64TTIImpl::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();
// Inline a callee if its target-features are a subset of the callers
// target-features.
return (CallerBits & CalleeBits) == CalleeBits;
}
/// Calculate the cost of materializing a 64-bit value. This helper
/// method might only calculate a fraction of a larger immediate. Therefore it
/// is valid to return a cost of ZERO.
int AArch64TTIImpl::getIntImmCost(int64_t Val) {
// Check if the immediate can be encoded within an instruction.
if (Val == 0 || AArch64_AM::isLogicalImmediate(Val, 64))
return 0;
if (Val < 0)
Val = ~Val;
// Calculate how many moves we will need to materialize this constant.
SmallVector<AArch64_IMM::ImmInsnModel, 4> Insn;
AArch64_IMM::expandMOVImm(Val, 64, Insn);
return Insn.size();
}
/// Calculate the cost of materializing the given constant.
int AArch64TTIImpl::getIntImmCost(const APInt &Imm, Type *Ty) {
assert(Ty->isIntegerTy());
unsigned BitSize = Ty->getPrimitiveSizeInBits();
if (BitSize == 0)
return ~0U;
// Sign-extend all constants to a multiple of 64-bit.
APInt ImmVal = Imm;
if (BitSize & 0x3f)
ImmVal = Imm.sext((BitSize + 63) & ~0x3fU);
// Split the constant into 64-bit chunks and calculate the cost for each
// chunk.
int Cost = 0;
for (unsigned ShiftVal = 0; ShiftVal < BitSize; ShiftVal += 64) {
APInt Tmp = ImmVal.ashr(ShiftVal).sextOrTrunc(64);
int64_t Val = Tmp.getSExtValue();
Cost += getIntImmCost(Val);
}
// We need at least one instruction to materialze the constant.
return std::max(1, Cost);
}
int AArch64TTIImpl::getIntImmCostInst(unsigned Opcode, unsigned Idx,
const APInt &Imm, Type *Ty) {
assert(Ty->isIntegerTy());
unsigned BitSize = Ty->getPrimitiveSizeInBits();
// There is no cost model for constants with a bit size of 0. Return TCC_Free
// here, so that constant hoisting will ignore this constant.
if (BitSize == 0)
return TTI::TCC_Free;
unsigned ImmIdx = ~0U;
switch (Opcode) {
default:
return TTI::TCC_Free;
case Instruction::GetElementPtr:
// Always hoist the base address of a GetElementPtr.
if (Idx == 0)
return 2 * TTI::TCC_Basic;
return TTI::TCC_Free;
case Instruction::Store:
ImmIdx = 0;
break;
case Instruction::Add:
case Instruction::Sub:
case Instruction::Mul:
case Instruction::UDiv:
case Instruction::SDiv:
case Instruction::URem:
case Instruction::SRem:
case Instruction::And:
case Instruction::Or:
case Instruction::Xor:
case Instruction::ICmp:
ImmIdx = 1;
break;
// Always return TCC_Free for the shift value of a shift instruction.
case Instruction::Shl:
case Instruction::LShr:
case Instruction::AShr:
if (Idx == 1)
return TTI::TCC_Free;
break;
case Instruction::Trunc:
case Instruction::ZExt:
case Instruction::SExt:
case Instruction::IntToPtr:
case Instruction::PtrToInt:
case Instruction::BitCast:
case Instruction::PHI:
case Instruction::Call:
case Instruction::Select:
case Instruction::Ret:
case Instruction::Load:
break;
}
if (Idx == ImmIdx) {
int NumConstants = (BitSize + 63) / 64;
int Cost = AArch64TTIImpl::getIntImmCost(Imm, Ty);
return (Cost <= NumConstants * TTI::TCC_Basic)
? static_cast<int>(TTI::TCC_Free)
: Cost;
}
return AArch64TTIImpl::getIntImmCost(Imm, Ty);
}
int AArch64TTIImpl::getIntImmCostIntrin(Intrinsic::ID IID, unsigned Idx,
const APInt &Imm, Type *Ty) {
assert(Ty->isIntegerTy());
unsigned BitSize = Ty->getPrimitiveSizeInBits();
// There is no cost model for constants with a bit size of 0. Return TCC_Free
// here, so that constant hoisting will ignore this constant.
if (BitSize == 0)
return TTI::TCC_Free;
// Most (all?) AArch64 intrinsics do not support folding immediates into the
// selected instruction, so we compute the materialization cost for the
// immediate directly.
if (IID >= Intrinsic::aarch64_addg && IID <= Intrinsic::aarch64_udiv)
return AArch64TTIImpl::getIntImmCost(Imm, Ty);
switch (IID) {
default:
return TTI::TCC_Free;
case Intrinsic::sadd_with_overflow:
case Intrinsic::uadd_with_overflow:
case Intrinsic::ssub_with_overflow:
case Intrinsic::usub_with_overflow:
case Intrinsic::smul_with_overflow:
case Intrinsic::umul_with_overflow:
if (Idx == 1) {
int NumConstants = (BitSize + 63) / 64;
int Cost = AArch64TTIImpl::getIntImmCost(Imm, Ty);
return (Cost <= NumConstants * TTI::TCC_Basic)
? static_cast<int>(TTI::TCC_Free)
: Cost;
}
break;
case Intrinsic::experimental_stackmap:
if ((Idx < 2) || (Imm.getBitWidth() <= 64 && isInt<64>(Imm.getSExtValue())))
return TTI::TCC_Free;
break;
case Intrinsic::experimental_patchpoint_void:
case Intrinsic::experimental_patchpoint_i64:
if ((Idx < 4) || (Imm.getBitWidth() <= 64 && isInt<64>(Imm.getSExtValue())))
return TTI::TCC_Free;
break;
}
return AArch64TTIImpl::getIntImmCost(Imm, Ty);
}
TargetTransformInfo::PopcntSupportKind
AArch64TTIImpl::getPopcntSupport(unsigned TyWidth) {
assert(isPowerOf2_32(TyWidth) && "Ty width must be power of 2");
if (TyWidth == 32 || TyWidth == 64)
return TTI::PSK_FastHardware;
// TODO: AArch64TargetLowering::LowerCTPOP() supports 128bit popcount.
return TTI::PSK_Software;
}
bool AArch64TTIImpl::isWideningInstruction(Type *DstTy, unsigned Opcode,
ArrayRef<const Value *> Args) {
// A helper that returns a vector type from the given type. The number of
// elements in type Ty determine the vector width.
auto toVectorTy = [&](Type *ArgTy) {
return VectorType::get(ArgTy->getScalarType(),
DstTy->getVectorNumElements());
};
// Exit early if DstTy is not a vector type whose elements are at least
// 16-bits wide.
if (!DstTy->isVectorTy() || DstTy->getScalarSizeInBits() < 16)
return false;
// Determine if the operation has a widening variant. We consider both the
// "long" (e.g., usubl) and "wide" (e.g., usubw) versions of the
// instructions.
//
// TODO: Add additional widening operations (e.g., mul, shl, etc.) once we
// verify that their extending operands are eliminated during code
// generation.
switch (Opcode) {
case Instruction::Add: // UADDL(2), SADDL(2), UADDW(2), SADDW(2).
case Instruction::Sub: // USUBL(2), SSUBL(2), USUBW(2), SSUBW(2).
break;
default:
return false;
}
// To be a widening instruction (either the "wide" or "long" versions), the
// second operand must be a sign- or zero extend having a single user. We
// only consider extends having a single user because they may otherwise not
// be eliminated.
if (Args.size() != 2 ||
(!isa<SExtInst>(Args[1]) && !isa<ZExtInst>(Args[1])) ||
!Args[1]->hasOneUse())
return false;
auto *Extend = cast<CastInst>(Args[1]);
// Legalize the destination type and ensure it can be used in a widening
// operation.
auto DstTyL = TLI->getTypeLegalizationCost(DL, DstTy);
unsigned DstElTySize = DstTyL.second.getScalarSizeInBits();
if (!DstTyL.second.isVector() || DstElTySize != DstTy->getScalarSizeInBits())
return false;
// Legalize the source type and ensure it can be used in a widening
// operation.
Type *SrcTy = toVectorTy(Extend->getSrcTy());
auto SrcTyL = TLI->getTypeLegalizationCost(DL, SrcTy);
unsigned SrcElTySize = SrcTyL.second.getScalarSizeInBits();
if (!SrcTyL.second.isVector() || SrcElTySize != SrcTy->getScalarSizeInBits())
return false;
// Get the total number of vector elements in the legalized types.
unsigned NumDstEls = DstTyL.first * DstTyL.second.getVectorNumElements();
unsigned NumSrcEls = SrcTyL.first * SrcTyL.second.getVectorNumElements();
// Return true if the legalized types have the same number of vector elements
// and the destination element type size is twice that of the source type.
return NumDstEls == NumSrcEls && 2 * SrcElTySize == DstElTySize;
}
int AArch64TTIImpl::getCastInstrCost(unsigned Opcode, Type *Dst, Type *Src,
const Instruction *I) {
int ISD = TLI->InstructionOpcodeToISD(Opcode);
assert(ISD && "Invalid opcode");
// If the cast is observable, and it is used by a widening instruction (e.g.,
// uaddl, saddw, etc.), it may be free.
if (I && I->hasOneUse()) {
auto *SingleUser = cast<Instruction>(*I->user_begin());
SmallVector<const Value *, 4> Operands(SingleUser->operand_values());
if (isWideningInstruction(Dst, SingleUser->getOpcode(), Operands)) {
// If the cast is the second operand, it is free. We will generate either
// a "wide" or "long" version of the widening instruction.
if (I == SingleUser->getOperand(1))
return 0;
// If the cast is not the second operand, it will be free if it looks the
// same as the second operand. In this case, we will generate a "long"
// version of the widening instruction.
if (auto *Cast = dyn_cast<CastInst>(SingleUser->getOperand(1)))
if (I->getOpcode() == unsigned(Cast->getOpcode()) &&
cast<CastInst>(I)->getSrcTy() == Cast->getSrcTy())
return 0;
}
}
EVT SrcTy = TLI->getValueType(DL, Src);
EVT DstTy = TLI->getValueType(DL, Dst);
if (!SrcTy.isSimple() || !DstTy.isSimple())
return BaseT::getCastInstrCost(Opcode, Dst, Src);
static const TypeConversionCostTblEntry
ConversionTbl[] = {
{ ISD::TRUNCATE, MVT::v4i16, MVT::v4i32, 1 },
{ ISD::TRUNCATE, MVT::v4i32, MVT::v4i64, 0 },
{ ISD::TRUNCATE, MVT::v8i8, MVT::v8i32, 3 },
{ ISD::TRUNCATE, MVT::v16i8, MVT::v16i32, 6 },
// The number of shll instructions for the extension.
{ ISD::SIGN_EXTEND, MVT::v4i64, MVT::v4i16, 3 },
{ ISD::ZERO_EXTEND, MVT::v4i64, MVT::v4i16, 3 },
{ ISD::SIGN_EXTEND, MVT::v4i64, MVT::v4i32, 2 },
{ ISD::ZERO_EXTEND, MVT::v4i64, MVT::v4i32, 2 },
{ ISD::SIGN_EXTEND, MVT::v8i32, MVT::v8i8, 3 },
{ ISD::ZERO_EXTEND, MVT::v8i32, MVT::v8i8, 3 },
{ ISD::SIGN_EXTEND, MVT::v8i32, MVT::v8i16, 2 },
{ ISD::ZERO_EXTEND, MVT::v8i32, MVT::v8i16, 2 },
{ ISD::SIGN_EXTEND, MVT::v8i64, MVT::v8i8, 7 },
{ ISD::ZERO_EXTEND, MVT::v8i64, MVT::v8i8, 7 },
{ ISD::SIGN_EXTEND, MVT::v8i64, MVT::v8i16, 6 },
{ ISD::ZERO_EXTEND, MVT::v8i64, MVT::v8i16, 6 },
{ ISD::SIGN_EXTEND, MVT::v16i16, MVT::v16i8, 2 },
{ ISD::ZERO_EXTEND, MVT::v16i16, MVT::v16i8, 2 },
{ ISD::SIGN_EXTEND, MVT::v16i32, MVT::v16i8, 6 },
{ ISD::ZERO_EXTEND, MVT::v16i32, MVT::v16i8, 6 },
// LowerVectorINT_TO_FP:
{ ISD::SINT_TO_FP, MVT::v2f32, MVT::v2i32, 1 },
{ ISD::SINT_TO_FP, MVT::v4f32, MVT::v4i32, 1 },
{ ISD::SINT_TO_FP, MVT::v2f64, MVT::v2i64, 1 },
{ ISD::UINT_TO_FP, MVT::v2f32, MVT::v2i32, 1 },
{ ISD::UINT_TO_FP, MVT::v4f32, MVT::v4i32, 1 },
{ ISD::UINT_TO_FP, MVT::v2f64, MVT::v2i64, 1 },
// Complex: to v2f32
{ ISD::SINT_TO_FP, MVT::v2f32, MVT::v2i8, 3 },
{ ISD::SINT_TO_FP, MVT::v2f32, MVT::v2i16, 3 },
{ ISD::SINT_TO_FP, MVT::v2f32, MVT::v2i64, 2 },
{ ISD::UINT_TO_FP, MVT::v2f32, MVT::v2i8, 3 },
{ ISD::UINT_TO_FP, MVT::v2f32, MVT::v2i16, 3 },
{ ISD::UINT_TO_FP, MVT::v2f32, MVT::v2i64, 2 },
// Complex: to v4f32
{ ISD::SINT_TO_FP, MVT::v4f32, MVT::v4i8, 4 },
{ ISD::SINT_TO_FP, MVT::v4f32, MVT::v4i16, 2 },
{ ISD::UINT_TO_FP, MVT::v4f32, MVT::v4i8, 3 },
{ ISD::UINT_TO_FP, MVT::v4f32, MVT::v4i16, 2 },
// Complex: to v8f32
{ ISD::SINT_TO_FP, MVT::v8f32, MVT::v8i8, 10 },
{ ISD::SINT_TO_FP, MVT::v8f32, MVT::v8i16, 4 },
{ ISD::UINT_TO_FP, MVT::v8f32, MVT::v8i8, 10 },
{ ISD::UINT_TO_FP, MVT::v8f32, MVT::v8i16, 4 },
// Complex: to v16f32
{ ISD::SINT_TO_FP, MVT::v16f32, MVT::v16i8, 21 },
{ ISD::UINT_TO_FP, MVT::v16f32, MVT::v16i8, 21 },
// Complex: to v2f64
{ ISD::SINT_TO_FP, MVT::v2f64, MVT::v2i8, 4 },
{ ISD::SINT_TO_FP, MVT::v2f64, MVT::v2i16, 4 },
{ ISD::SINT_TO_FP, MVT::v2f64, MVT::v2i32, 2 },
{ ISD::UINT_TO_FP, MVT::v2f64, MVT::v2i8, 4 },
{ ISD::UINT_TO_FP, MVT::v2f64, MVT::v2i16, 4 },
{ ISD::UINT_TO_FP, MVT::v2f64, MVT::v2i32, 2 },
// LowerVectorFP_TO_INT
{ ISD::FP_TO_SINT, MVT::v2i32, MVT::v2f32, 1 },
{ ISD::FP_TO_SINT, MVT::v4i32, MVT::v4f32, 1 },
{ ISD::FP_TO_SINT, MVT::v2i64, MVT::v2f64, 1 },
{ ISD::FP_TO_UINT, MVT::v2i32, MVT::v2f32, 1 },
{ ISD::FP_TO_UINT, MVT::v4i32, MVT::v4f32, 1 },
{ ISD::FP_TO_UINT, MVT::v2i64, MVT::v2f64, 1 },
// Complex, from v2f32: legal type is v2i32 (no cost) or v2i64 (1 ext).
{ ISD::FP_TO_SINT, MVT::v2i64, MVT::v2f32, 2 },
{ ISD::FP_TO_SINT, MVT::v2i16, MVT::v2f32, 1 },
{ ISD::FP_TO_SINT, MVT::v2i8, MVT::v2f32, 1 },
{ ISD::FP_TO_UINT, MVT::v2i64, MVT::v2f32, 2 },
{ ISD::FP_TO_UINT, MVT::v2i16, MVT::v2f32, 1 },
{ ISD::FP_TO_UINT, MVT::v2i8, MVT::v2f32, 1 },
// Complex, from v4f32: legal type is v4i16, 1 narrowing => ~2
{ ISD::FP_TO_SINT, MVT::v4i16, MVT::v4f32, 2 },
{ ISD::FP_TO_SINT, MVT::v4i8, MVT::v4f32, 2 },
{ ISD::FP_TO_UINT, MVT::v4i16, MVT::v4f32, 2 },
{ ISD::FP_TO_UINT, MVT::v4i8, MVT::v4f32, 2 },
// Complex, from v2f64: legal type is v2i32, 1 narrowing => ~2.
{ ISD::FP_TO_SINT, MVT::v2i32, MVT::v2f64, 2 },
{ ISD::FP_TO_SINT, MVT::v2i16, MVT::v2f64, 2 },
{ ISD::FP_TO_SINT, MVT::v2i8, MVT::v2f64, 2 },
{ ISD::FP_TO_UINT, MVT::v2i32, MVT::v2f64, 2 },
{ ISD::FP_TO_UINT, MVT::v2i16, MVT::v2f64, 2 },
{ ISD::FP_TO_UINT, MVT::v2i8, MVT::v2f64, 2 },
};
if (const auto *Entry = ConvertCostTableLookup(ConversionTbl, ISD,
DstTy.getSimpleVT(),
SrcTy.getSimpleVT()))
return Entry->Cost;
return BaseT::getCastInstrCost(Opcode, Dst, Src);
}
int AArch64TTIImpl::getExtractWithExtendCost(unsigned Opcode, Type *Dst,
VectorType *VecTy,
unsigned Index) {
// Make sure we were given a valid extend opcode.
assert((Opcode == Instruction::SExt || Opcode == Instruction::ZExt) &&
"Invalid opcode");
// We are extending an element we extract from a vector, so the source type
// of the extend is the element type of the vector.
auto *Src = VecTy->getElementType();
// Sign- and zero-extends are for integer types only.
assert(isa<IntegerType>(Dst) && isa<IntegerType>(Src) && "Invalid type");
// Get the cost for the extract. We compute the cost (if any) for the extend
// below.
auto Cost = getVectorInstrCost(Instruction::ExtractElement, VecTy, Index);
// Legalize the types.
auto VecLT = TLI->getTypeLegalizationCost(DL, VecTy);
auto DstVT = TLI->getValueType(DL, Dst);
auto SrcVT = TLI->getValueType(DL, Src);
// If the resulting type is still a vector and the destination type is legal,
// we may get the extension for free. If not, get the default cost for the
// extend.
if (!VecLT.second.isVector() || !TLI->isTypeLegal(DstVT))
return Cost + getCastInstrCost(Opcode, Dst, Src);
// The destination type should be larger than the element type. If not, get
// the default cost for the extend.
if (DstVT.getSizeInBits() < SrcVT.getSizeInBits())
return Cost + getCastInstrCost(Opcode, Dst, Src);
switch (Opcode) {
default:
llvm_unreachable("Opcode should be either SExt or ZExt");
// For sign-extends, we only need a smov, which performs the extension
// automatically.
case Instruction::SExt:
return Cost;
// For zero-extends, the extend is performed automatically by a umov unless
// the destination type is i64 and the element type is i8 or i16.
case Instruction::ZExt:
if (DstVT.getSizeInBits() != 64u || SrcVT.getSizeInBits() == 32u)
return Cost;
}
// If we are unable to perform the extend for free, get the default cost.
return Cost + getCastInstrCost(Opcode, Dst, Src);
}
int AArch64TTIImpl::getVectorInstrCost(unsigned Opcode, Type *Val,
unsigned Index) {
assert(Val->isVectorTy() && "This must be a vector type");
if (Index != -1U) {
// Legalize the type.
std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, Val);
// This type is legalized to a scalar type.
if (!LT.second.isVector())
return 0;
// The type may be split. Normalize the index to the new type.
unsigned Width = LT.second.getVectorNumElements();
Index = Index % Width;
// The element at index zero is already inside the vector.
if (Index == 0)
return 0;
}
// All other insert/extracts cost this much.
return ST->getVectorInsertExtractBaseCost();
}
int AArch64TTIImpl::getArithmeticInstrCost(
unsigned Opcode, Type *Ty, TTI::OperandValueKind Opd1Info,
TTI::OperandValueKind Opd2Info, TTI::OperandValueProperties Opd1PropInfo,
TTI::OperandValueProperties Opd2PropInfo, ArrayRef<const Value *> Args,
const Instruction *CxtI) {
// Legalize the type.
std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, Ty);
// If the instruction is a widening instruction (e.g., uaddl, saddw, etc.),
// add in the widening overhead specified by the sub-target. Since the
// extends feeding widening instructions are performed automatically, they
// aren't present in the generated code and have a zero cost. By adding a
// widening overhead here, we attach the total cost of the combined operation
// to the widening instruction.
int Cost = 0;
if (isWideningInstruction(Ty, Opcode, Args))
Cost += ST->getWideningBaseCost();
int ISD = TLI->InstructionOpcodeToISD(Opcode);
switch (ISD) {
default:
return Cost + BaseT::getArithmeticInstrCost(Opcode, Ty, Opd1Info, Opd2Info,
Opd1PropInfo, Opd2PropInfo);
case ISD::SDIV:
if (Opd2Info == TargetTransformInfo::OK_UniformConstantValue &&
Opd2PropInfo == TargetTransformInfo::OP_PowerOf2) {
// On AArch64, scalar signed division by constants power-of-two are
// normally expanded to the sequence ADD + CMP + SELECT + SRA.
// The OperandValue properties many not be same as that of previous
// operation; conservatively assume OP_None.
Cost += getArithmeticInstrCost(Instruction::Add, Ty, Opd1Info, Opd2Info,
TargetTransformInfo::OP_None,
TargetTransformInfo::OP_None);
Cost += getArithmeticInstrCost(Instruction::Sub, Ty, Opd1Info, Opd2Info,
TargetTransformInfo::OP_None,
TargetTransformInfo::OP_None);
Cost += getArithmeticInstrCost(Instruction::Select, Ty, Opd1Info, Opd2Info,
TargetTransformInfo::OP_None,
TargetTransformInfo::OP_None);
Cost += getArithmeticInstrCost(Instruction::AShr, Ty, Opd1Info, Opd2Info,
TargetTransformInfo::OP_None,
TargetTransformInfo::OP_None);
return Cost;
}
LLVM_FALLTHROUGH;
case ISD::UDIV:
if (Opd2Info == TargetTransformInfo::OK_UniformConstantValue) {
auto VT = TLI->getValueType(DL, Ty);
if (TLI->isOperationLegalOrCustom(ISD::MULHU, VT)) {
// Vector signed division by constant are expanded to the
// sequence MULHS + ADD/SUB + SRA + SRL + ADD, and unsigned division
// to MULHS + SUB + SRL + ADD + SRL.
int MulCost = getArithmeticInstrCost(Instruction::Mul, Ty, Opd1Info,
Opd2Info,
TargetTransformInfo::OP_None,
TargetTransformInfo::OP_None);
int AddCost = getArithmeticInstrCost(Instruction::Add, Ty, Opd1Info,
Opd2Info,
TargetTransformInfo::OP_None,
TargetTransformInfo::OP_None);
int ShrCost = getArithmeticInstrCost(Instruction::AShr, Ty, Opd1Info,
Opd2Info,
TargetTransformInfo::OP_None,
TargetTransformInfo::OP_None);
return MulCost * 2 + AddCost * 2 + ShrCost * 2 + 1;
}
}
Cost += BaseT::getArithmeticInstrCost(Opcode, Ty, Opd1Info, Opd2Info,
Opd1PropInfo, Opd2PropInfo);
if (Ty->isVectorTy()) {
// On AArch64, vector divisions are not supported natively and are
// expanded into scalar divisions of each pair of elements.
Cost += getArithmeticInstrCost(Instruction::ExtractElement, Ty, Opd1Info,
Opd2Info, Opd1PropInfo, Opd2PropInfo);
Cost += getArithmeticInstrCost(Instruction::InsertElement, Ty, Opd1Info,
Opd2Info, Opd1PropInfo, Opd2PropInfo);
// TODO: if one of the arguments is scalar, then it's not necessary to
// double the cost of handling the vector elements.
Cost += Cost;
}
return Cost;
case ISD::ADD:
case ISD::MUL:
case ISD::XOR:
case ISD::OR:
case ISD::AND:
// These nodes are marked as 'custom' for combining purposes only.
// We know that they are legal. See LowerAdd in ISelLowering.
return (Cost + 1) * LT.first;
}
}
int AArch64TTIImpl::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 (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;
}
int AArch64TTIImpl::getCmpSelInstrCost(unsigned Opcode, Type *ValTy,
Type *CondTy, const Instruction *I) {
int ISD = TLI->InstructionOpcodeToISD(Opcode);
// We don't lower some vector selects well that are wider than the register
// width.
if (ValTy->isVectorTy() && ISD == ISD::SELECT) {
// We would need this many instructions to hide the scalarization happening.
const int AmortizationCost = 20;
static const TypeConversionCostTblEntry
VectorSelectTbl[] = {
{ ISD::SELECT, MVT::v16i1, MVT::v16i16, 16 },
{ ISD::SELECT, MVT::v8i1, MVT::v8i32, 8 },
{ ISD::SELECT, MVT::v16i1, MVT::v16i32, 16 },
{ ISD::SELECT, MVT::v4i1, MVT::v4i64, 4 * AmortizationCost },
{ ISD::SELECT, MVT::v8i1, MVT::v8i64, 8 * AmortizationCost },
{ ISD::SELECT, MVT::v16i1, MVT::v16i64, 16 * AmortizationCost }
};
EVT SelCondTy = TLI->getValueType(DL, CondTy);
EVT SelValTy = TLI->getValueType(DL, ValTy);
if (SelCondTy.isSimple() && SelValTy.isSimple()) {
if (const auto *Entry = ConvertCostTableLookup(VectorSelectTbl, ISD,
SelCondTy.getSimpleVT(),
SelValTy.getSimpleVT()))
return Entry->Cost;
}
}
return BaseT::getCmpSelInstrCost(Opcode, ValTy, CondTy, I);
}
AArch64TTIImpl::TTI::MemCmpExpansionOptions
AArch64TTIImpl::enableMemCmpExpansion(bool OptSize, bool IsZeroCmp) const {
TTI::MemCmpExpansionOptions Options;
Options.AllowOverlappingLoads = !ST->requiresStrictAlign();
Options.MaxNumLoads = TLI->getMaxExpandSizeMemcmp(OptSize);
Options.NumLoadsPerBlock = Options.MaxNumLoads;
// TODO: Though vector loads usually perform well on AArch64, in some targets
// they may wake up the FP unit, which raises the power consumption. Perhaps
// they could be used with no holds barred (-O3).
Options.LoadSizes = {8, 4, 2, 1};
return Options;
}
int AArch64TTIImpl::getMemoryOpCost(unsigned Opcode, Type *Ty,
MaybeAlign Alignment, unsigned AddressSpace,
const Instruction *I) {
auto LT = TLI->getTypeLegalizationCost(DL, Ty);
if (ST->isMisaligned128StoreSlow() && Opcode == Instruction::Store &&
LT.second.is128BitVector() && (!Alignment || *Alignment < Align(16))) {
// Unaligned stores are extremely inefficient. We don't split all
// unaligned 128-bit stores because the negative impact that has shown in
// practice on inlined block copy code.
// We make such stores expensive so that we will only vectorize if there
// are 6 other instructions getting vectorized.
const int AmortizationCost = 6;
return LT.first * 2 * AmortizationCost;
}
if (Ty->isVectorTy() && Ty->getVectorElementType()->isIntegerTy(8)) {
unsigned ProfitableNumElements;
if (Opcode == Instruction::Store)
// We use a custom trunc store lowering so v.4b should be profitable.
ProfitableNumElements = 4;
else
// We scalarize the loads because there is not v.4b register and we
// have to promote the elements to v.2.
ProfitableNumElements = 8;
if (Ty->getVectorNumElements() < ProfitableNumElements) {
unsigned NumVecElts = Ty->getVectorNumElements();
unsigned NumVectorizableInstsToAmortize = NumVecElts * 2;
// We generate 2 instructions per vector element.
return NumVectorizableInstsToAmortize * NumVecElts * 2;
}
}
return LT.first;
}
int AArch64TTIImpl::getInterleavedMemoryOpCost(unsigned Opcode, Type *VecTy,
unsigned Factor,
ArrayRef<unsigned> Indices,
unsigned Alignment,
unsigned AddressSpace,
bool UseMaskForCond,
bool UseMaskForGaps) {
assert(Factor >= 2 && "Invalid interleave factor");
assert(isa<VectorType>(VecTy) && "Expect a vector type");
if (!UseMaskForCond && !UseMaskForGaps &&
Factor <= TLI->getMaxSupportedInterleaveFactor()) {
unsigned NumElts = VecTy->getVectorNumElements();
auto *SubVecTy = VectorType::get(VecTy->getScalarType(), NumElts / Factor);
// ldN/stN 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 ldN/stN instruction.
if (NumElts % Factor == 0 &&
TLI->isLegalInterleavedAccessType(SubVecTy, DL))
return Factor * TLI->getNumInterleavedAccesses(SubVecTy, DL);
}
return BaseT::getInterleavedMemoryOpCost(Opcode, VecTy, Factor, Indices,
Alignment, AddressSpace,
UseMaskForCond, UseMaskForGaps);
}
int AArch64TTIImpl::getCostOfKeepingLiveOverCall(ArrayRef<Type *> Tys) {
int Cost = 0;
for (auto *I : Tys) {
if (!I->isVectorTy())
continue;
if (I->getScalarSizeInBits() * I->getVectorNumElements() == 128)
Cost += getMemoryOpCost(Instruction::Store, I, Align(128), 0) +
getMemoryOpCost(Instruction::Load, I, Align(128), 0);
}
return Cost;
}
unsigned AArch64TTIImpl::getMaxInterleaveFactor(unsigned VF) {
return ST->getMaxInterleaveFactor();
}
// For Falkor, we want to avoid having too many strided loads in a loop since
// that can exhaust the HW prefetcher resources. We adjust the unroller
// MaxCount preference below to attempt to ensure unrolling doesn't create too
// many strided loads.
static void
getFalkorUnrollingPreferences(Loop *L, ScalarEvolution &SE,
TargetTransformInfo::UnrollingPreferences &UP) {
enum { MaxStridedLoads = 7 };
auto countStridedLoads = [](Loop *L, ScalarEvolution &SE) {
int StridedLoads = 0;
// FIXME? We could make this more precise by looking at the CFG and
// e.g. not counting loads in each side of an if-then-else diamond.
for (const auto BB : L->blocks()) {
for (auto &I : *BB) {
LoadInst *LMemI = dyn_cast<LoadInst>(&I);
if (!LMemI)
continue;
Value *PtrValue = LMemI->getPointerOperand();
if (L->isLoopInvariant(PtrValue))
continue;
const SCEV *LSCEV = SE.getSCEV(PtrValue);
const SCEVAddRecExpr *LSCEVAddRec = dyn_cast<SCEVAddRecExpr>(LSCEV);
if (!LSCEVAddRec || !LSCEVAddRec->isAffine())
continue;
// FIXME? We could take pairing of unrolled load copies into account
// by looking at the AddRec, but we would probably have to limit this
// to loops with no stores or other memory optimization barriers.
++StridedLoads;
// We've seen enough strided loads that seeing more won't make a
// difference.
if (StridedLoads > MaxStridedLoads / 2)
return StridedLoads;
}
}
return StridedLoads;
};
int StridedLoads = countStridedLoads(L, SE);
LLVM_DEBUG(dbgs() << "falkor-hwpf: detected " << StridedLoads
<< " strided loads\n");
// Pick the largest power of 2 unroll count that won't result in too many
// strided loads.
if (StridedLoads) {
UP.MaxCount = 1 << Log2_32(MaxStridedLoads / StridedLoads);
LLVM_DEBUG(dbgs() << "falkor-hwpf: setting unroll MaxCount to "
<< UP.MaxCount << '\n');
}
}
void AArch64TTIImpl::getUnrollingPreferences(Loop *L, ScalarEvolution &SE,
TTI::UnrollingPreferences &UP) {
// Enable partial unrolling and runtime unrolling.
BaseT::getUnrollingPreferences(L, SE, UP);
// For inner loop, it is more likely to be a hot one, and the runtime check
// can be promoted out from LICM pass, so the overhead is less, let's try
// a larger threshold to unroll more loops.
if (L->getLoopDepth() > 1)
UP.PartialThreshold *= 2;
// Disable partial & runtime unrolling on -Os.
UP.PartialOptSizeThreshold = 0;
if (ST->getProcFamily() == AArch64Subtarget::Falkor &&
EnableFalkorHWPFUnrollFix)
getFalkorUnrollingPreferences(L, SE, UP);
}
Value *AArch64TTIImpl::getOrCreateResultFromMemIntrinsic(IntrinsicInst *Inst,
Type *ExpectedType) {
switch (Inst->getIntrinsicID()) {
default:
return nullptr;
case Intrinsic::aarch64_neon_st2:
case Intrinsic::aarch64_neon_st3:
case Intrinsic::aarch64_neon_st4: {
// Create a struct type
StructType *ST = dyn_cast<StructType>(ExpectedType);
if (!ST)
return nullptr;
unsigned NumElts = Inst->getNumArgOperands() - 1;
if (ST->getNumElements() != NumElts)
return nullptr;
for (unsigned i = 0, e = NumElts; i != e; ++i) {
if (Inst->getArgOperand(i)->getType() != ST->getElementType(i))
return nullptr;
}
Value *Res = UndefValue::get(ExpectedType);
IRBuilder<> Builder(Inst);
for (unsigned i = 0, e = NumElts; i != e; ++i) {
Value *L = Inst->getArgOperand(i);
Res = Builder.CreateInsertValue(Res, L, i);
}
return Res;
}
case Intrinsic::aarch64_neon_ld2:
case Intrinsic::aarch64_neon_ld3:
case Intrinsic::aarch64_neon_ld4:
if (Inst->getType() == ExpectedType)
return Inst;
return nullptr;
}
}
bool AArch64TTIImpl::getTgtMemIntrinsic(IntrinsicInst *Inst,
MemIntrinsicInfo &Info) {
switch (Inst->getIntrinsicID()) {
default:
break;
case Intrinsic::aarch64_neon_ld2:
case Intrinsic::aarch64_neon_ld3:
case Intrinsic::aarch64_neon_ld4:
Info.ReadMem = true;
Info.WriteMem = false;
Info.PtrVal = Inst->getArgOperand(0);
break;
case Intrinsic::aarch64_neon_st2:
case Intrinsic::aarch64_neon_st3:
case Intrinsic::aarch64_neon_st4:
Info.ReadMem = false;
Info.WriteMem = true;
Info.PtrVal = Inst->getArgOperand(Inst->getNumArgOperands() - 1);
break;
}
switch (Inst->getIntrinsicID()) {
default:
return false;
case Intrinsic::aarch64_neon_ld2:
case Intrinsic::aarch64_neon_st2:
Info.MatchingId = VECTOR_LDST_TWO_ELEMENTS;
break;
case Intrinsic::aarch64_neon_ld3:
case Intrinsic::aarch64_neon_st3:
Info.MatchingId = VECTOR_LDST_THREE_ELEMENTS;
break;
case Intrinsic::aarch64_neon_ld4:
case Intrinsic::aarch64_neon_st4:
Info.MatchingId = VECTOR_LDST_FOUR_ELEMENTS;
break;
}
return true;
}
/// See if \p I should be considered for address type promotion. We check if \p
/// I is a sext with right type and used in memory accesses. If it used in a
/// "complex" getelementptr, we allow it to be promoted without finding other
/// sext instructions that sign extended the same initial value. A getelementptr
/// is considered as "complex" if it has more than 2 operands.
bool AArch64TTIImpl::shouldConsiderAddressTypePromotion(
const Instruction &I, bool &AllowPromotionWithoutCommonHeader) {
bool Considerable = false;
AllowPromotionWithoutCommonHeader = false;
if (!isa<SExtInst>(&I))
return false;
Type *ConsideredSExtType =
Type::getInt64Ty(I.getParent()->getParent()->getContext());
if (I.getType() != ConsideredSExtType)
return false;
// See if the sext is the one with the right type and used in at least one
// GetElementPtrInst.
for (const User *U : I.users()) {
if (const GetElementPtrInst *GEPInst = dyn_cast<GetElementPtrInst>(U)) {
Considerable = true;
// A getelementptr is considered as "complex" if it has more than 2
// operands. We will promote a SExt used in such complex GEP as we
// expect some computation to be merged if they are done on 64 bits.
if (GEPInst->getNumOperands() > 2) {
AllowPromotionWithoutCommonHeader = true;
break;
}
}
}
return Considerable;
}
bool AArch64TTIImpl::useReductionIntrinsic(unsigned Opcode, Type *Ty,
TTI::ReductionFlags Flags) const {
assert(isa<VectorType>(Ty) && "Expected Ty to be a vector type");
unsigned ScalarBits = Ty->getScalarSizeInBits();
switch (Opcode) {
case Instruction::FAdd:
case Instruction::FMul:
case Instruction::And:
case Instruction::Or:
case Instruction::Xor:
case Instruction::Mul:
return false;
case Instruction::Add:
return ScalarBits * Ty->getVectorNumElements() >= 128;
case Instruction::ICmp:
return (ScalarBits < 64) &&
(ScalarBits * Ty->getVectorNumElements() >= 128);
case Instruction::FCmp:
return Flags.NoNaN;
default:
llvm_unreachable("Unhandled reduction opcode");
}
return false;
}
int AArch64TTIImpl::getArithmeticReductionCost(unsigned Opcode, Type *ValTy,
bool IsPairwiseForm) {
if (IsPairwiseForm)
return BaseT::getArithmeticReductionCost(Opcode, ValTy, IsPairwiseForm);
std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, ValTy);
MVT MTy = LT.second;
int ISD = TLI->InstructionOpcodeToISD(Opcode);
assert(ISD && "Invalid opcode");
// Horizontal adds can use the 'addv' instruction. We model the cost of these
// instructions as normal vector adds. This is the only arithmetic vector
// reduction operation for which we have an instruction.
static const CostTblEntry CostTblNoPairwise[]{
{ISD::ADD, MVT::v8i8, 1},
{ISD::ADD, MVT::v16i8, 1},
{ISD::ADD, MVT::v4i16, 1},
{ISD::ADD, MVT::v8i16, 1},
{ISD::ADD, MVT::v4i32, 1},
};
if (const auto *Entry = CostTableLookup(CostTblNoPairwise, ISD, MTy))
return LT.first * Entry->Cost;
return BaseT::getArithmeticReductionCost(Opcode, ValTy, IsPairwiseForm);
}
int AArch64TTIImpl::getShuffleCost(TTI::ShuffleKind Kind, Type *Tp, int Index,
Type *SubTp) {
if (Kind == TTI::SK_Broadcast || Kind == TTI::SK_Transpose ||
Kind == TTI::SK_Select || Kind == TTI::SK_PermuteSingleSrc) {
static const CostTblEntry ShuffleTbl[] = {
// Broadcast shuffle kinds can be performed with 'dup'.
{ TTI::SK_Broadcast, MVT::v8i8, 1 },
{ TTI::SK_Broadcast, MVT::v16i8, 1 },
{ TTI::SK_Broadcast, MVT::v4i16, 1 },
{ TTI::SK_Broadcast, MVT::v8i16, 1 },
{ TTI::SK_Broadcast, MVT::v2i32, 1 },
{ TTI::SK_Broadcast, MVT::v4i32, 1 },
{ TTI::SK_Broadcast, MVT::v2i64, 1 },
{ TTI::SK_Broadcast, MVT::v2f32, 1 },
{ TTI::SK_Broadcast, MVT::v4f32, 1 },
{ TTI::SK_Broadcast, MVT::v2f64, 1 },
// Transpose shuffle kinds can be performed with 'trn1/trn2' and
// 'zip1/zip2' instructions.
{ TTI::SK_Transpose, MVT::v8i8, 1 },
{ TTI::SK_Transpose, MVT::v16i8, 1 },
{ TTI::SK_Transpose, MVT::v4i16, 1 },
{ TTI::SK_Transpose, MVT::v8i16, 1 },
{ TTI::SK_Transpose, MVT::v2i32, 1 },
{ TTI::SK_Transpose, MVT::v4i32, 1 },
{ TTI::SK_Transpose, MVT::v2i64, 1 },
{ TTI::SK_Transpose, MVT::v2f32, 1 },
{ TTI::SK_Transpose, MVT::v4f32, 1 },
{ TTI::SK_Transpose, MVT::v2f64, 1 },
// Select shuffle kinds.
// TODO: handle vXi8/vXi16.
{ TTI::SK_Select, MVT::v2i32, 1 }, // mov.
{ TTI::SK_Select, MVT::v4i32, 2 }, // rev+trn (or similar).
{ TTI::SK_Select, MVT::v2i64, 1 }, // mov.
{ TTI::SK_Select, MVT::v2f32, 1 }, // mov.
{ TTI::SK_Select, MVT::v4f32, 2 }, // rev+trn (or similar).
{ TTI::SK_Select, MVT::v2f64, 1 }, // mov.
// PermuteSingleSrc shuffle kinds.
// TODO: handle vXi8/vXi16.
{ TTI::SK_PermuteSingleSrc, MVT::v2i32, 1 }, // mov.
{ TTI::SK_PermuteSingleSrc, MVT::v4i32, 3 }, // perfectshuffle worst case.
{ TTI::SK_PermuteSingleSrc, MVT::v2i64, 1 }, // mov.
{ TTI::SK_PermuteSingleSrc, MVT::v2f32, 1 }, // mov.
{ TTI::SK_PermuteSingleSrc, MVT::v4f32, 3 }, // perfectshuffle worst case.
{ TTI::SK_PermuteSingleSrc, MVT::v2f64, 1 }, // mov.
};
std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, Tp);
if (const auto *Entry = CostTableLookup(ShuffleTbl, Kind, LT.second))
return LT.first * Entry->Cost;
}
return BaseT::getShuffleCost(Kind, Tp, Index, SubTp);
}