RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-23 19:23:23 +01:00
Code Issues Projects Releases Wiki Activity
70c7e49d44
llvm-mirror/lib/Target/PowerPC/PPCTargetTransformInfo.cpp
Sam Parker c7b113e4d1 [NFCI][CostModel] Unify getCmpSelInstrCost 
Add cases for icmp, fcmp and select into the switch statement of the
generic getUserCost implementation with getInstructionThroughput then
calling into it. The BasicTTI and backend implementations have be set
to return a default value (1) when a cost other than throughput is
being queried.

Differential Revision: https://reviews.llvm.org/D80550
2020-06-09 07:41:22 +01:00

1018 lines
38 KiB
C++
Raw Blame History

//===-- PPCTargetTransformInfo.cpp - PPC 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 "PPCTargetTransformInfo.h"
#include "llvm/Analysis/CodeMetrics.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/CodeGen/BasicTTIImpl.h"
#include "llvm/CodeGen/CostTable.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/CodeGen/TargetSchedule.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
using namespace llvm;
#define DEBUG_TYPE "ppctti"
static cl::opt<bool> DisablePPCConstHoist("disable-ppc-constant-hoisting",
cl::desc("disable constant hoisting on PPC"), cl::init(false), cl::Hidden);
// This is currently only used for the data prefetch pass which is only enabled
// for BG/Q by default.
static cl::opt<unsigned>
CacheLineSize("ppc-loop-prefetch-cache-line", cl::Hidden, cl::init(64),
cl::desc("The loop prefetch cache line size"));
static cl::opt<bool>
EnablePPCColdCC("ppc-enable-coldcc", cl::Hidden, cl::init(false),
cl::desc("Enable using coldcc calling conv for cold "
"internal functions"));
static cl::opt<bool>
LsrNoInsnsCost("ppc-lsr-no-insns-cost", cl::Hidden, cl::init(false),
cl::desc("Do not add instruction count to lsr cost model"));
// The latency of mtctr is only justified if there are more than 4
// comparisons that will be removed as a result.
static cl::opt<unsigned>
SmallCTRLoopThreshold("min-ctr-loop-threshold", cl::init(4), cl::Hidden,
cl::desc("Loops with a constant trip count smaller than "
"this value will not use the count register."));
//===----------------------------------------------------------------------===//
//
// PPC cost model.
//
//===----------------------------------------------------------------------===//
TargetTransformInfo::PopcntSupportKind
PPCTTIImpl::getPopcntSupport(unsigned TyWidth) {
assert(isPowerOf2_32(TyWidth) && "Ty width must be power of 2");
if (ST->hasPOPCNTD() != PPCSubtarget::POPCNTD_Unavailable && TyWidth <= 64)
return ST->hasPOPCNTD() == PPCSubtarget::POPCNTD_Slow ?
TTI::PSK_SlowHardware : TTI::PSK_FastHardware;
return TTI::PSK_Software;
}
int PPCTTIImpl::getIntImmCost(const APInt &Imm, Type *Ty,
TTI::TargetCostKind CostKind) {
if (DisablePPCConstHoist)
return BaseT::getIntImmCost(Imm, Ty, CostKind);
assert(Ty->isIntegerTy());
unsigned BitSize = Ty->getPrimitiveSizeInBits();
if (BitSize == 0)
return ~0U;
if (Imm == 0)
return TTI::TCC_Free;
if (Imm.getBitWidth() <= 64) {
if (isInt<16>(Imm.getSExtValue()))
return TTI::TCC_Basic;
if (isInt<32>(Imm.getSExtValue())) {
// A constant that can be materialized using lis.
if ((Imm.getZExtValue() & 0xFFFF) == 0)
return TTI::TCC_Basic;
return 2 * TTI::TCC_Basic;
}
}
return 4 * TTI::TCC_Basic;
}
int PPCTTIImpl::getIntImmCostIntrin(Intrinsic::ID IID, unsigned Idx,
const APInt &Imm, Type *Ty,
TTI::TargetCostKind CostKind) {
if (DisablePPCConstHoist)
return BaseT::getIntImmCostIntrin(IID, Idx, Imm, Ty, CostKind);
assert(Ty->isIntegerTy());
unsigned BitSize = Ty->getPrimitiveSizeInBits();
if (BitSize == 0)
return ~0U;
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:
if ((Idx == 1) && Imm.getBitWidth() <= 64 && isInt<16>(Imm.getSExtValue()))
return TTI::TCC_Free;
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 PPCTTIImpl::getIntImmCost(Imm, Ty, CostKind);
}
int PPCTTIImpl::getIntImmCostInst(unsigned Opcode, unsigned Idx,
const APInt &Imm, Type *Ty,
TTI::TargetCostKind CostKind) {
if (DisablePPCConstHoist)
return BaseT::getIntImmCostInst(Opcode, Idx, Imm, Ty, CostKind);
assert(Ty->isIntegerTy());
unsigned BitSize = Ty->getPrimitiveSizeInBits();
if (BitSize == 0)
return ~0U;
unsigned ImmIdx = ~0U;
bool ShiftedFree = false, RunFree = false, UnsignedFree = false,
ZeroFree = false;
switch (Opcode) {
default:
return TTI::TCC_Free;
case Instruction::GetElementPtr:
// Always hoist the base address of a GetElementPtr. This prevents the
// creation of new constants for every base constant that gets constant
// folded with the offset.
if (Idx == 0)
return 2 * TTI::TCC_Basic;
return TTI::TCC_Free;
case Instruction::And:
RunFree = true; // (for the rotate-and-mask instructions)
LLVM_FALLTHROUGH;
case Instruction::Add:
case Instruction::Or:
case Instruction::Xor:
ShiftedFree = true;
LLVM_FALLTHROUGH;
case Instruction::Sub:
case Instruction::Mul:
case Instruction::Shl:
case Instruction::LShr:
case Instruction::AShr:
ImmIdx = 1;
break;
case Instruction::ICmp:
UnsignedFree = true;
ImmIdx = 1;
// Zero comparisons can use record-form instructions.
LLVM_FALLTHROUGH;
case Instruction::Select:
ZeroFree = true;
break;
case Instruction::PHI:
case Instruction::Call:
case Instruction::Ret:
case Instruction::Load:
case Instruction::Store:
break;
}
if (ZeroFree && Imm == 0)
return TTI::TCC_Free;
if (Idx == ImmIdx && Imm.getBitWidth() <= 64) {
if (isInt<16>(Imm.getSExtValue()))
return TTI::TCC_Free;
if (RunFree) {
if (Imm.getBitWidth() <= 32 &&
(isShiftedMask_32(Imm.getZExtValue()) ||
isShiftedMask_32(~Imm.getZExtValue())))
return TTI::TCC_Free;
if (ST->isPPC64() &&
(isShiftedMask_64(Imm.getZExtValue()) ||
isShiftedMask_64(~Imm.getZExtValue())))
return TTI::TCC_Free;
}
if (UnsignedFree && isUInt<16>(Imm.getZExtValue()))
return TTI::TCC_Free;
if (ShiftedFree && (Imm.getZExtValue() & 0xFFFF) == 0)
return TTI::TCC_Free;
}
return PPCTTIImpl::getIntImmCost(Imm, Ty, CostKind);
}
unsigned
PPCTTIImpl::getUserCost(const User *U, ArrayRef<const Value *> Operands,
TTI::TargetCostKind CostKind) {
// We already implement getCastInstrCost and getMemoryOpCost where we perform
// the vector adjustment there.
if (isa<CastInst>(U) || isa<LoadInst>(U) || isa<StoreInst>(U))
return BaseT::getUserCost(U, Operands, CostKind);
if (U->getType()->isVectorTy()) {
// Instructions that need to be split should cost more.
std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, U->getType());
return LT.first * BaseT::getUserCost(U, Operands, CostKind);
}
return BaseT::getUserCost(U, Operands, CostKind);
}
bool PPCTTIImpl::mightUseCTR(BasicBlock *BB, TargetLibraryInfo *LibInfo,
SmallPtrSetImpl<const Value *> &Visited) {
const PPCTargetMachine &TM = ST->getTargetMachine();
// Loop through the inline asm constraints and look for something that
// clobbers ctr.
auto asmClobbersCTR = [](InlineAsm *IA) {
InlineAsm::ConstraintInfoVector CIV = IA->ParseConstraints();
for (unsigned i = 0, ie = CIV.size(); i < ie; ++i) {
InlineAsm::ConstraintInfo &C = CIV[i];
if (C.Type != InlineAsm::isInput)
for (unsigned j = 0, je = C.Codes.size(); j < je; ++j)
if (StringRef(C.Codes[j]).equals_lower("{ctr}"))
return true;
}
return false;
};
// Determining the address of a TLS variable results in a function call in
// certain TLS models.
std::function<bool(const Value *)> memAddrUsesCTR =
[&memAddrUsesCTR, &TM, &Visited](const Value *MemAddr) -> bool {
// No need to traverse again if we already checked this operand.
if (!Visited.insert(MemAddr).second)
return false;
const auto *GV = dyn_cast<GlobalValue>(MemAddr);
if (!GV) {
// Recurse to check for constants that refer to TLS global variables.
if (const auto *CV = dyn_cast<Constant>(MemAddr))
for (const auto &CO : CV->operands())
if (memAddrUsesCTR(CO))
return true;
return false;
}
if (!GV->isThreadLocal())
return false;
TLSModel::Model Model = TM.getTLSModel(GV);
return Model == TLSModel::GeneralDynamic ||
Model == TLSModel::LocalDynamic;
};
auto isLargeIntegerTy = [](bool Is32Bit, Type *Ty) {
if (IntegerType *ITy = dyn_cast<IntegerType>(Ty))
return ITy->getBitWidth() > (Is32Bit ? 32U : 64U);
return false;
};
for (BasicBlock::iterator J = BB->begin(), JE = BB->end();
J != JE; ++J) {
if (CallInst *CI = dyn_cast<CallInst>(J)) {
// Inline ASM is okay, unless it clobbers the ctr register.
if (InlineAsm *IA = dyn_cast<InlineAsm>(CI->getCalledOperand())) {
if (asmClobbersCTR(IA))
return true;
continue;
}
if (Function *F = CI->getCalledFunction()) {
// Most intrinsics don't become function calls, but some might.
// sin, cos, exp and log are always calls.
unsigned Opcode = 0;
if (F->getIntrinsicID() != Intrinsic::not_intrinsic) {
switch (F->getIntrinsicID()) {
default: continue;
// If we have a call to ppc_is_decremented_ctr_nonzero, or ppc_mtctr
// we're definitely using CTR.
case Intrinsic::set_loop_iterations:
case Intrinsic::loop_decrement:
return true;
// Exclude eh_sjlj_setjmp; we don't need to exclude eh_sjlj_longjmp
// because, although it does clobber the counter register, the
// control can't then return to inside the loop unless there is also
// an eh_sjlj_setjmp.
case Intrinsic::eh_sjlj_setjmp:
case Intrinsic::memcpy:
case Intrinsic::memmove:
case Intrinsic::memset:
case Intrinsic::powi:
case Intrinsic::log:
case Intrinsic::log2:
case Intrinsic::log10:
case Intrinsic::exp:
case Intrinsic::exp2:
case Intrinsic::pow:
case Intrinsic::sin:
case Intrinsic::cos:
return true;
case Intrinsic::copysign:
if (CI->getArgOperand(0)->getType()->getScalarType()->
isPPC_FP128Ty())
return true;
else
continue; // ISD::FCOPYSIGN is never a library call.
case Intrinsic::fma: Opcode = ISD::FMA; break;
case Intrinsic::sqrt: Opcode = ISD::FSQRT; break;
case Intrinsic::floor: Opcode = ISD::FFLOOR; break;
case Intrinsic::ceil: Opcode = ISD::FCEIL; break;
case Intrinsic::trunc: Opcode = ISD::FTRUNC; break;
case Intrinsic::rint: Opcode = ISD::FRINT; break;
case Intrinsic::lrint: Opcode = ISD::LRINT; break;
case Intrinsic::llrint: Opcode = ISD::LLRINT; break;
case Intrinsic::nearbyint: Opcode = ISD::FNEARBYINT; break;
case Intrinsic::round: Opcode = ISD::FROUND; break;
case Intrinsic::lround: Opcode = ISD::LROUND; break;
case Intrinsic::llround: Opcode = ISD::LLROUND; break;
case Intrinsic::minnum: Opcode = ISD::FMINNUM; break;
case Intrinsic::maxnum: Opcode = ISD::FMAXNUM; break;
case Intrinsic::umul_with_overflow: Opcode = ISD::UMULO; break;
case Intrinsic::smul_with_overflow: Opcode = ISD::SMULO; break;
}
}
// PowerPC does not use [US]DIVREM or other library calls for
// operations on regular types which are not otherwise library calls
// (i.e. soft float or atomics). If adapting for targets that do,
// additional care is required here.
LibFunc Func;
if (!F->hasLocalLinkage() && F->hasName() && LibInfo &&
LibInfo->getLibFunc(F->getName(), Func) &&
LibInfo->hasOptimizedCodeGen(Func)) {
// Non-read-only functions are never treated as intrinsics.
if (!CI->onlyReadsMemory())
return true;
// Conversion happens only for FP calls.
if (!CI->getArgOperand(0)->getType()->isFloatingPointTy())
return true;
switch (Func) {
default: return true;
case LibFunc_copysign:
case LibFunc_copysignf:
continue; // ISD::FCOPYSIGN is never a library call.
case LibFunc_copysignl:
return true;
case LibFunc_fabs:
case LibFunc_fabsf:
case LibFunc_fabsl:
continue; // ISD::FABS is never a library call.
case LibFunc_sqrt:
case LibFunc_sqrtf:
case LibFunc_sqrtl:
Opcode = ISD::FSQRT; break;
case LibFunc_floor:
case LibFunc_floorf:
case LibFunc_floorl:
Opcode = ISD::FFLOOR; break;
case LibFunc_nearbyint:
case LibFunc_nearbyintf:
case LibFunc_nearbyintl:
Opcode = ISD::FNEARBYINT; break;
case LibFunc_ceil:
case LibFunc_ceilf:
case LibFunc_ceill:
Opcode = ISD::FCEIL; break;
case LibFunc_rint:
case LibFunc_rintf:
case LibFunc_rintl:
Opcode = ISD::FRINT; break;
case LibFunc_round:
case LibFunc_roundf:
case LibFunc_roundl:
Opcode = ISD::FROUND; break;
case LibFunc_trunc:
case LibFunc_truncf:
case LibFunc_truncl:
Opcode = ISD::FTRUNC; break;
case LibFunc_fmin:
case LibFunc_fminf:
case LibFunc_fminl:
Opcode = ISD::FMINNUM; break;
case LibFunc_fmax:
case LibFunc_fmaxf:
case LibFunc_fmaxl:
Opcode = ISD::FMAXNUM; break;
}
}
if (Opcode) {
EVT EVTy =
TLI->getValueType(DL, CI->getArgOperand(0)->getType(), true);
if (EVTy == MVT::Other)
return true;
if (TLI->isOperationLegalOrCustom(Opcode, EVTy))
continue;
else if (EVTy.isVector() &&
TLI->isOperationLegalOrCustom(Opcode, EVTy.getScalarType()))
continue;
return true;
}
}
return true;
} else if (isa<BinaryOperator>(J) &&
J->getType()->getScalarType()->isPPC_FP128Ty()) {
// Most operations on ppc_f128 values become calls.
return true;
} else if (isa<UIToFPInst>(J) || isa<SIToFPInst>(J) ||
isa<FPToUIInst>(J) || isa<FPToSIInst>(J)) {
CastInst *CI = cast<CastInst>(J);
if (CI->getSrcTy()->getScalarType()->isPPC_FP128Ty() ||
CI->getDestTy()->getScalarType()->isPPC_FP128Ty() ||
isLargeIntegerTy(!TM.isPPC64(), CI->getSrcTy()->getScalarType()) ||
isLargeIntegerTy(!TM.isPPC64(), CI->getDestTy()->getScalarType()))
return true;
} else if (isLargeIntegerTy(!TM.isPPC64(),
J->getType()->getScalarType()) &&
(J->getOpcode() == Instruction::UDiv ||
J->getOpcode() == Instruction::SDiv ||
J->getOpcode() == Instruction::URem ||
J->getOpcode() == Instruction::SRem)) {
return true;
} else if (!TM.isPPC64() &&
isLargeIntegerTy(false, J->getType()->getScalarType()) &&
(J->getOpcode() == Instruction::Shl ||
J->getOpcode() == Instruction::AShr ||
J->getOpcode() == Instruction::LShr)) {
// Only on PPC32, for 128-bit integers (specifically not 64-bit
// integers), these might be runtime calls.
return true;
} else if (isa<IndirectBrInst>(J) || isa<InvokeInst>(J)) {
// On PowerPC, indirect jumps use the counter register.
return true;
} else if (SwitchInst *SI = dyn_cast<SwitchInst>(J)) {
if (SI->getNumCases() + 1 >= (unsigned)TLI->getMinimumJumpTableEntries())
return true;
}
// FREM is always a call.
if (J->getOpcode() == Instruction::FRem)
return true;
if (ST->useSoftFloat()) {
switch(J->getOpcode()) {
case Instruction::FAdd:
case Instruction::FSub:
case Instruction::FMul:
case Instruction::FDiv:
case Instruction::FPTrunc:
case Instruction::FPExt:
case Instruction::FPToUI:
case Instruction::FPToSI:
case Instruction::UIToFP:
case Instruction::SIToFP:
case Instruction::FCmp:
return true;
}
}
for (Value *Operand : J->operands())
if (memAddrUsesCTR(Operand))
return true;
}
return false;
}
bool PPCTTIImpl::isHardwareLoopProfitable(Loop *L, ScalarEvolution &SE,
AssumptionCache &AC,
TargetLibraryInfo *LibInfo,
HardwareLoopInfo &HWLoopInfo) {
const PPCTargetMachine &TM = ST->getTargetMachine();
TargetSchedModel SchedModel;
SchedModel.init(ST);
// Do not convert small short loops to CTR loop.
unsigned ConstTripCount = SE.getSmallConstantTripCount(L);
if (ConstTripCount && ConstTripCount < SmallCTRLoopThreshold) {
SmallPtrSet<const Value *, 32> EphValues;
CodeMetrics::collectEphemeralValues(L, &AC, EphValues);
CodeMetrics Metrics;
for (BasicBlock *BB : L->blocks())
Metrics.analyzeBasicBlock(BB, *this, EphValues);
// 6 is an approximate latency for the mtctr instruction.
if (Metrics.NumInsts <= (6 * SchedModel.getIssueWidth()))
return false;
}
// We don't want to spill/restore the counter register, and so we don't
// want to use the counter register if the loop contains calls.
SmallPtrSet<const Value *, 4> Visited;
for (Loop::block_iterator I = L->block_begin(), IE = L->block_end();
I != IE; ++I)
if (mightUseCTR(*I, LibInfo, Visited))
return false;
SmallVector<BasicBlock*, 4> ExitingBlocks;
L->getExitingBlocks(ExitingBlocks);
// If there is an exit edge known to be frequently taken,
// we should not transform this loop.
for (auto &BB : ExitingBlocks) {
Instruction *TI = BB->getTerminator();
if (!TI) continue;
if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
uint64_t TrueWeight = 0, FalseWeight = 0;
if (!BI->isConditional() ||
!BI->extractProfMetadata(TrueWeight, FalseWeight))
continue;
// If the exit path is more frequent than the loop path,
// we return here without further analysis for this loop.
bool TrueIsExit = !L->contains(BI->getSuccessor(0));
if (( TrueIsExit && FalseWeight < TrueWeight) ||
(!TrueIsExit && FalseWeight > TrueWeight))
return false;
}
}
LLVMContext &C = L->getHeader()->getContext();
HWLoopInfo.CountType = TM.isPPC64() ?
Type::getInt64Ty(C) : Type::getInt32Ty(C);
HWLoopInfo.LoopDecrement = ConstantInt::get(HWLoopInfo.CountType, 1);
return true;
}
void PPCTTIImpl::getUnrollingPreferences(Loop *L, ScalarEvolution &SE,
TTI::UnrollingPreferences &UP) {
if (ST->getCPUDirective() == PPC::DIR_A2) {
// The A2 is in-order with a deep pipeline, and concatenation unrolling
// helps expose latency-hiding opportunities to the instruction scheduler.
UP.Partial = UP.Runtime = true;
// We unroll a lot on the A2 (hundreds of instructions), and the benefits
// often outweigh the cost of a division to compute the trip count.
UP.AllowExpensiveTripCount = true;
}
BaseT::getUnrollingPreferences(L, SE, UP);
}
// This function returns true to allow using coldcc calling convention.
// Returning true results in coldcc being used for functions which are cold at
// all call sites when the callers of the functions are not calling any other
// non coldcc functions.
bool PPCTTIImpl::useColdCCForColdCall(Function &F) {
return EnablePPCColdCC;
}
bool PPCTTIImpl::enableAggressiveInterleaving(bool LoopHasReductions) {
// On the A2, always unroll aggressively. For QPX unaligned loads, we depend
// on combining the loads generated for consecutive accesses, and failure to
// do so is particularly expensive. This makes it much more likely (compared
// to only using concatenation unrolling).
if (ST->getCPUDirective() == PPC::DIR_A2)
return true;
return LoopHasReductions;
}
PPCTTIImpl::TTI::MemCmpExpansionOptions
PPCTTIImpl::enableMemCmpExpansion(bool OptSize, bool IsZeroCmp) const {
TTI::MemCmpExpansionOptions Options;
Options.LoadSizes = {8, 4, 2, 1};
Options.MaxNumLoads = TLI->getMaxExpandSizeMemcmp(OptSize);
return Options;
}
bool PPCTTIImpl::enableInterleavedAccessVectorization() {
return true;
}
unsigned PPCTTIImpl::getNumberOfRegisters(unsigned ClassID) const {
assert(ClassID == GPRRC || ClassID == FPRRC ||
ClassID == VRRC || ClassID == VSXRC);
if (ST->hasVSX()) {
assert(ClassID == GPRRC || ClassID == VSXRC || ClassID == VRRC);
return ClassID == VSXRC ? 64 : 32;
}
assert(ClassID == GPRRC || ClassID == FPRRC || ClassID == VRRC);
return 32;
}
unsigned PPCTTIImpl::getRegisterClassForType(bool Vector, Type *Ty) const {
if (Vector)
return ST->hasVSX() ? VSXRC : VRRC;
else if (Ty && (Ty->getScalarType()->isFloatTy() ||
Ty->getScalarType()->isDoubleTy()))
return ST->hasVSX() ? VSXRC : FPRRC;
else if (Ty && (Ty->getScalarType()->isFP128Ty() ||
Ty->getScalarType()->isPPC_FP128Ty()))
return VRRC;
else if (Ty && Ty->getScalarType()->isHalfTy())
return VSXRC;
else
return GPRRC;
}
const char* PPCTTIImpl::getRegisterClassName(unsigned ClassID) const {
switch (ClassID) {
default:
llvm_unreachable("unknown register class");
return "PPC::unknown register class";
case GPRRC: return "PPC::GPRRC";
case FPRRC: return "PPC::FPRRC";
case VRRC: return "PPC::VRRC";
case VSXRC: return "PPC::VSXRC";
}
}
unsigned PPCTTIImpl::getRegisterBitWidth(bool Vector) const {
if (Vector) {
if (ST->hasQPX()) return 256;
if (ST->hasAltivec()) return 128;
return 0;
}
if (ST->isPPC64())
return 64;
return 32;
}
unsigned PPCTTIImpl::getCacheLineSize() const {
// Check first if the user specified a custom line size.
if (CacheLineSize.getNumOccurrences() > 0)
return CacheLineSize;
// Starting with P7 we have a cache line size of 128.
unsigned Directive = ST->getCPUDirective();
// Assume that Future CPU has the same cache line size as the others.
if (Directive == PPC::DIR_PWR7 || Directive == PPC::DIR_PWR8 ||
Directive == PPC::DIR_PWR9 || Directive == PPC::DIR_PWR10 ||
Directive == PPC::DIR_PWR_FUTURE)
return 128;
// On other processors return a default of 64 bytes.
return 64;
}
unsigned PPCTTIImpl::getPrefetchDistance() const {
// This seems like a reasonable default for the BG/Q (this pass is enabled, by
// default, only on the BG/Q).
return 300;
}
unsigned PPCTTIImpl::getMaxInterleaveFactor(unsigned VF) {
unsigned Directive = ST->getCPUDirective();
// The 440 has no SIMD support, but floating-point instructions
// have a 5-cycle latency, so unroll by 5x for latency hiding.
if (Directive == PPC::DIR_440)
return 5;
// The A2 has no SIMD support, but floating-point instructions
// have a 6-cycle latency, so unroll by 6x for latency hiding.
if (Directive == PPC::DIR_A2)
return 6;
// FIXME: For lack of any better information, do no harm...
if (Directive == PPC::DIR_E500mc || Directive == PPC::DIR_E5500)
return 1;
// For P7 and P8, floating-point instructions have a 6-cycle latency and
// there are two execution units, so unroll by 12x for latency hiding.
// FIXME: the same for P9 as previous gen until POWER9 scheduling is ready
// FIXME: the same for P10 as previous gen until POWER10 scheduling is ready
// Assume that future is the same as the others.
if (Directive == PPC::DIR_PWR7 || Directive == PPC::DIR_PWR8 ||
Directive == PPC::DIR_PWR9 || Directive == PPC::DIR_PWR10 ||
Directive == PPC::DIR_PWR_FUTURE)
return 12;
// For most things, modern systems have two execution units (and
// out-of-order execution).
return 2;
}
// Adjust the cost of vector instructions on targets which there is overlap
// between the vector and scalar units, thereby reducing the overall throughput
// of vector code wrt. scalar code.
int PPCTTIImpl::vectorCostAdjustment(int Cost, unsigned Opcode, Type *Ty1,
Type *Ty2) {
if (!ST->vectorsUseTwoUnits() || !Ty1->isVectorTy())
return Cost;
std::pair<int, MVT> LT1 = TLI->getTypeLegalizationCost(DL, Ty1);
// If type legalization involves splitting the vector, we don't want to
// double the cost at every step - only the last step.
if (LT1.first != 1 || !LT1.second.isVector())
return Cost;
int ISD = TLI->InstructionOpcodeToISD(Opcode);
if (TLI->isOperationExpand(ISD, LT1.second))
return Cost;
if (Ty2) {
std::pair<int, MVT> LT2 = TLI->getTypeLegalizationCost(DL, Ty2);
if (LT2.first != 1 || !LT2.second.isVector())
return Cost;
}
return Cost * 2;
}
int PPCTTIImpl::getArithmeticInstrCost(unsigned Opcode, Type *Ty,
TTI::TargetCostKind CostKind,
TTI::OperandValueKind Op1Info,
TTI::OperandValueKind Op2Info,
TTI::OperandValueProperties Opd1PropInfo,
TTI::OperandValueProperties Opd2PropInfo,
ArrayRef<const Value *> Args,
const Instruction *CxtI) {
assert(TLI->InstructionOpcodeToISD(Opcode) && "Invalid opcode");
// Fallback to the default implementation.
int Cost = BaseT::getArithmeticInstrCost(Opcode, Ty, CostKind, Op1Info,
Op2Info,
Opd1PropInfo, Opd2PropInfo);
return vectorCostAdjustment(Cost, Opcode, Ty, nullptr);
}
int PPCTTIImpl::getShuffleCost(TTI::ShuffleKind Kind, Type *Tp, int Index,
Type *SubTp) {
// Legalize the type.
std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, Tp);
// PPC, for both Altivec/VSX and QPX, support cheap arbitrary permutations
// (at least in the sense that there need only be one non-loop-invariant
// instruction). We need one such shuffle instruction for each actual
// register (this is not true for arbitrary shuffles, but is true for the
// structured types of shuffles covered by TTI::ShuffleKind).
return vectorCostAdjustment(LT.first, Instruction::ShuffleVector, Tp,
nullptr);
}
int PPCTTIImpl::getCastInstrCost(unsigned Opcode, Type *Dst, Type *Src,
TTI::TargetCostKind CostKind,
const Instruction *I) {
assert(TLI->InstructionOpcodeToISD(Opcode) && "Invalid opcode");
int Cost = BaseT::getCastInstrCost(Opcode, Dst, Src, CostKind, I);
Cost = vectorCostAdjustment(Cost, Opcode, Dst, Src);
// TODO: Allow non-throughput costs that aren't binary.
if (CostKind != TTI::TCK_RecipThroughput)
return Cost == 0 ? 0 : 1;
return Cost;
}
int PPCTTIImpl::getCmpSelInstrCost(unsigned Opcode, Type *ValTy, Type *CondTy,
TTI::TargetCostKind CostKind,
const Instruction *I) {
int Cost = BaseT::getCmpSelInstrCost(Opcode, ValTy, CondTy, CostKind, I);
// TODO: Handle other cost kinds.
if (CostKind != TTI::TCK_RecipThroughput)
return Cost;
return vectorCostAdjustment(Cost, Opcode, ValTy, nullptr);
}
int PPCTTIImpl::getVectorInstrCost(unsigned Opcode, Type *Val, unsigned Index) {
assert(Val->isVectorTy() && "This must be a vector type");
int ISD = TLI->InstructionOpcodeToISD(Opcode);
assert(ISD && "Invalid opcode");
int Cost = BaseT::getVectorInstrCost(Opcode, Val, Index);
Cost = vectorCostAdjustment(Cost, Opcode, Val, nullptr);
if (ST->hasVSX() && Val->getScalarType()->isDoubleTy()) {
// Double-precision scalars are already located in index #0 (or #1 if LE).
if (ISD == ISD::EXTRACT_VECTOR_ELT &&
Index == (ST->isLittleEndian() ? 1 : 0))
return 0;
return Cost;
} else if (ST->hasQPX() && Val->getScalarType()->isFloatingPointTy()) {
// Floating point scalars are already located in index #0.
if (Index == 0)
return 0;
return Cost;
} else if (Val->getScalarType()->isIntegerTy() && Index != -1U) {
if (ST->hasP9Altivec()) {
if (ISD == ISD::INSERT_VECTOR_ELT)
// A move-to VSR and a permute/insert. Assume vector operation cost
// for both (cost will be 2x on P9).
return vectorCostAdjustment(2, Opcode, Val, nullptr);
// It's an extract. Maybe we can do a cheap move-from VSR.
unsigned EltSize = Val->getScalarSizeInBits();
if (EltSize == 64) {
unsigned MfvsrdIndex = ST->isLittleEndian() ? 1 : 0;
if (Index == MfvsrdIndex)
return 1;
} else if (EltSize == 32) {
unsigned MfvsrwzIndex = ST->isLittleEndian() ? 2 : 1;
if (Index == MfvsrwzIndex)
return 1;
}
// We need a vector extract (or mfvsrld). Assume vector operation cost.
// The cost of the load constant for a vector extract is disregarded
// (invariant, easily schedulable).
return vectorCostAdjustment(1, Opcode, Val, nullptr);
} else if (ST->hasDirectMove())
// Assume permute has standard cost.
// Assume move-to/move-from VSR have 2x standard cost.
return 3;
}
// Estimated cost of a load-hit-store delay. This was obtained
// experimentally as a minimum needed to prevent unprofitable
// vectorization for the paq8p benchmark. It may need to be
// raised further if other unprofitable cases remain.
unsigned LHSPenalty = 2;
if (ISD == ISD::INSERT_VECTOR_ELT)
LHSPenalty += 7;
// Vector element insert/extract with Altivec is very expensive,
// because they require store and reload with the attendant
// processor stall for load-hit-store. Until VSX is available,
// these need to be estimated as very costly.
if (ISD == ISD::EXTRACT_VECTOR_ELT ||
ISD == ISD::INSERT_VECTOR_ELT)
return LHSPenalty + Cost;
return Cost;
}
int PPCTTIImpl::getMemoryOpCost(unsigned Opcode, Type *Src,
MaybeAlign Alignment, unsigned AddressSpace,
TTI::TargetCostKind CostKind,
const Instruction *I) {
if (TLI->getValueType(DL, Src, true) == MVT::Other)
return BaseT::getMemoryOpCost(Opcode, Src, Alignment, AddressSpace,
CostKind);
// Legalize the type.
std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, Src);
assert((Opcode == Instruction::Load || Opcode == Instruction::Store) &&
"Invalid Opcode");
int Cost = BaseT::getMemoryOpCost(Opcode, Src, Alignment, AddressSpace,
CostKind);
// TODO: Handle other cost kinds.
if (CostKind != TTI::TCK_RecipThroughput)
return Cost;
Cost = vectorCostAdjustment(Cost, Opcode, Src, nullptr);
bool IsAltivecType = ST->hasAltivec() &&
(LT.second == MVT::v16i8 || LT.second == MVT::v8i16 ||
LT.second == MVT::v4i32 || LT.second == MVT::v4f32);
bool IsVSXType = ST->hasVSX() &&
(LT.second == MVT::v2f64 || LT.second == MVT::v2i64);
bool IsQPXType = ST->hasQPX() &&
(LT.second == MVT::v4f64 || LT.second == MVT::v4f32);
// VSX has 32b/64b load instructions. Legalization can handle loading of
// 32b/64b to VSR correctly and cheaply. But BaseT::getMemoryOpCost and
// PPCTargetLowering can't compute the cost appropriately. So here we
// explicitly check this case.
unsigned MemBytes = Src->getPrimitiveSizeInBits();
if (Opcode == Instruction::Load && ST->hasVSX() && IsAltivecType &&
(MemBytes == 64 || (ST->hasP8Vector() && MemBytes == 32)))
return 1;
// Aligned loads and stores are easy.
unsigned SrcBytes = LT.second.getStoreSize();
if (!SrcBytes || !Alignment || *Alignment >= SrcBytes)
return Cost;
// If we can use the permutation-based load sequence, then this is also
// relatively cheap (not counting loop-invariant instructions): one load plus
// one permute (the last load in a series has extra cost, but we're
// neglecting that here). Note that on the P7, we could do unaligned loads
// for Altivec types using the VSX instructions, but that's more expensive
// than using the permutation-based load sequence. On the P8, that's no
// longer true.
if (Opcode == Instruction::Load &&
((!ST->hasP8Vector() && IsAltivecType) || IsQPXType) &&
*Alignment >= LT.second.getScalarType().getStoreSize())
return Cost + LT.first; // Add the cost of the permutations.
// For VSX, we can do unaligned loads and stores on Altivec/VSX types. On the
// P7, unaligned vector loads are more expensive than the permutation-based
// load sequence, so that might be used instead, but regardless, the net cost
// is about the same (not counting loop-invariant instructions).
if (IsVSXType || (ST->hasVSX() && IsAltivecType))
return Cost;
// Newer PPC supports unaligned memory access.
if (TLI->allowsMisalignedMemoryAccesses(LT.second, 0))
return Cost;
// PPC in general does not support unaligned loads and stores. They'll need
// to be decomposed based on the alignment factor.
// Add the cost of each scalar load or store.
assert(Alignment);
Cost += LT.first * ((SrcBytes / Alignment->value()) - 1);
// For a vector type, there is also scalarization overhead (only for
// stores, loads are expanded using the vector-load + permutation sequence,
// which is much less expensive).
if (Src->isVectorTy() && Opcode == Instruction::Store)
for (int i = 0, e = cast<FixedVectorType>(Src)->getNumElements(); i < e;
++i)
Cost += getVectorInstrCost(Instruction::ExtractElement, Src, i);
return Cost;
}
int PPCTTIImpl::getInterleavedMemoryOpCost(unsigned Opcode, Type *VecTy,
unsigned Factor,
ArrayRef<unsigned> Indices,
unsigned Alignment,
unsigned AddressSpace,
TTI::TargetCostKind CostKind,
bool UseMaskForCond,
bool UseMaskForGaps) {
if (UseMaskForCond || UseMaskForGaps)
return BaseT::getInterleavedMemoryOpCost(Opcode, VecTy, Factor, Indices,
Alignment, AddressSpace, CostKind,
UseMaskForCond, UseMaskForGaps);
assert(isa<VectorType>(VecTy) &&
"Expect a vector type for interleaved memory op");
// Legalize the type.
std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, VecTy);
// Firstly, the cost of load/store operation.
int Cost =
getMemoryOpCost(Opcode, VecTy, MaybeAlign(Alignment), AddressSpace,
CostKind);
// PPC, for both Altivec/VSX and QPX, support cheap arbitrary permutations
// (at least in the sense that there need only be one non-loop-invariant
// instruction). For each result vector, we need one shuffle per incoming
// vector (except that the first shuffle can take two incoming vectors
// because it does not need to take itself).
Cost += Factor*(LT.first-1);
return Cost;
}
unsigned PPCTTIImpl::getIntrinsicInstrCost(const IntrinsicCostAttributes &ICA,
TTI::TargetCostKind CostKind) {
return BaseT::getIntrinsicInstrCost(ICA, CostKind);
}
bool PPCTTIImpl::canSaveCmp(Loop *L, BranchInst **BI, ScalarEvolution *SE,
LoopInfo *LI, DominatorTree *DT,
AssumptionCache *AC, TargetLibraryInfo *LibInfo) {
// Process nested loops first.
for (Loop::iterator I = L->begin(), E = L->end(); I != E; ++I)
if (canSaveCmp(*I, BI, SE, LI, DT, AC, LibInfo))
return false; // Stop search.
HardwareLoopInfo HWLoopInfo(L);
if (!HWLoopInfo.canAnalyze(*LI))
return false;
if (!isHardwareLoopProfitable(L, *SE, *AC, LibInfo, HWLoopInfo))
return false;
if (!HWLoopInfo.isHardwareLoopCandidate(*SE, *LI, *DT))
return false;
*BI = HWLoopInfo.ExitBranch;
return true;
}
bool PPCTTIImpl::isLSRCostLess(TargetTransformInfo::LSRCost &C1,
TargetTransformInfo::LSRCost &C2) {
// PowerPC default behaviour here is "instruction number 1st priority".
// If LsrNoInsnsCost is set, call default implementation.
if (!LsrNoInsnsCost)
return std::tie(C1.Insns, C1.NumRegs, C1.AddRecCost, C1.NumIVMuls,
C1.NumBaseAdds, C1.ScaleCost, C1.ImmCost, C1.SetupCost) <
std::tie(C2.Insns, C2.NumRegs, C2.AddRecCost, C2.NumIVMuls,
C2.NumBaseAdds, C2.ScaleCost, C2.ImmCost, C2.SetupCost);
else
return TargetTransformInfoImplBase::isLSRCostLess(C1, C2);
}
Reference in New Issue View Git Blame Copy Permalink