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b2d6052871
llvm-mirror/lib/Target/ARM/ARMTargetTransformInfo.cpp
Chandler Carruth b2d6052871 [PM] Change the core design of the TTI analysis to use a polymorphic 
type erased interface and a single analysis pass rather than an
extremely complex analysis group.

The end result is that the TTI analysis can contain a type erased
implementation that supports the polymorphic TTI interface. We can build
one from a target-specific implementation or from a dummy one in the IR.

I've also factored all of the code into "mix-in"-able base classes,
including CRTP base classes to facilitate calling back up to the most
specialized form when delegating horizontally across the surface. These
aren't as clean as I would like and I'm planning to work on cleaning
some of this up, but I wanted to start by putting into the right form.

There are a number of reasons for this change, and this particular
design. The first and foremost reason is that an analysis group is
complete overkill, and the chaining delegation strategy was so opaque,
confusing, and high overhead that TTI was suffering greatly for it.
Several of the TTI functions had failed to be implemented in all places
because of the chaining-based delegation making there be no checking of
this. A few other functions were implemented with incorrect delegation.
The message to me was very clear working on this -- the delegation and
analysis group structure was too confusing to be useful here.

The other reason of course is that this is *much* more natural fit for
the new pass manager. This will lay the ground work for a type-erased
per-function info object that can look up the correct subtarget and even
cache it.

Yet another benefit is that this will significantly simplify the
interaction of the pass managers and the TargetMachine. See the future
work below.

The downside of this change is that it is very, very verbose. I'm going
to work to improve that, but it is somewhat an implementation necessity
in C++ to do type erasure. =/ I discussed this design really extensively
with Eric and Hal prior to going down this path, and afterward showed
them the result. No one was really thrilled with it, but there doesn't
seem to be a substantially better alternative. Using a base class and
virtual method dispatch would make the code much shorter, but as
discussed in the update to the programmer's manual and elsewhere,
a polymorphic interface feels like the more principled approach even if
this is perhaps the least compelling example of it. ;]

Ultimately, there is still a lot more to be done here, but this was the
huge chunk that I couldn't really split things out of because this was
the interface change to TTI. I've tried to minimize all the other parts
of this. The follow up work should include at least:

1) Improving the TargetMachine interface by having it directly return
   a TTI object. Because we have a non-pass object with value semantics
   and an internal type erasure mechanism, we can narrow the interface
   of the TargetMachine to *just* do what we need: build and return
   a TTI object that we can then insert into the pass pipeline.
2) Make the TTI object be fully specialized for a particular function.
   This will include splitting off a minimal form of it which is
   sufficient for the inliner and the old pass manager.
3) Add a new pass manager analysis which produces TTI objects from the
   target machine for each function. This may actually be done as part
   of #2 in order to use the new analysis to implement #2.
4) Work on narrowing the API between TTI and the targets so that it is
   easier to understand and less verbose to type erase.
5) Work on narrowing the API between TTI and its clients so that it is
   easier to understand and less verbose to forward.
6) Try to improve the CRTP-based delegation. I feel like this code is
   just a bit messy and exacerbating the complexity of implementing
   the TTI in each target.

Many thanks to Eric and Hal for their help here. I ended up blocked on
this somewhat more abruptly than I expected, and so I appreciate getting
it sorted out very quickly.

Differential Revision: http://reviews.llvm.org/D7293

llvm-svn: 227669
2015-01-31 03:43:40 +00:00

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//===-- ARMTargetTransformInfo.cpp - ARM specific TTI pass ----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
/// \file
/// This file implements a TargetTransformInfo analysis pass specific to the
/// ARM 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 "ARM.h"
#include "ARMTargetMachine.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/CodeGen/BasicTTIImpl.h"
#include "llvm/Support/Debug.h"
#include "llvm/Target/CostTable.h"
#include "llvm/Target/TargetLowering.h"
using namespace llvm;
#define DEBUG_TYPE "armtti"
namespace {
class ARMTTIImpl : public BasicTTIImplBase<ARMTTIImpl> {
typedef BasicTTIImplBase<ARMTTIImpl> BaseT;
typedef TargetTransformInfo TTI;
const ARMSubtarget *ST;
const ARMTargetLowering *TLI;
/// Estimate the overhead of scalarizing an instruction. Insert and Extract
/// are set if the result needs to be inserted and/or extracted from vectors.
unsigned getScalarizationOverhead(Type *Ty, bool Insert, bool Extract);
public:
explicit ARMTTIImpl(const ARMBaseTargetMachine *TM = nullptr)
: BaseT(TM), ST(TM ? TM->getSubtargetImpl() : nullptr),
TLI(ST ? ST->getTargetLowering() : nullptr) {}
// Provide value semantics. MSVC requires that we spell all of these out.
ARMTTIImpl(const ARMTTIImpl &Arg)
: BaseT(static_cast<const BaseT &>(Arg)), ST(Arg.ST), TLI(Arg.TLI) {}
ARMTTIImpl(ARMTTIImpl &&Arg)
: BaseT(std::move(static_cast<BaseT &>(Arg))), ST(std::move(Arg.ST)),
TLI(std::move(Arg.TLI)) {}
ARMTTIImpl &operator=(const ARMTTIImpl &RHS) {
BaseT::operator=(static_cast<const BaseT &>(RHS));
ST = RHS.ST;
TLI = RHS.TLI;
return *this;
}
ARMTTIImpl &operator=(ARMTTIImpl &&RHS) {
BaseT::operator=(std::move(static_cast<BaseT &>(RHS)));
ST = std::move(RHS.ST);
TLI = std::move(RHS.TLI);
return *this;
}
/// \name Scalar TTI Implementations
/// @{
using BaseT::getIntImmCost;
unsigned getIntImmCost(const APInt &Imm, Type *Ty);
/// @}
/// \name Vector TTI Implementations
/// @{
unsigned getNumberOfRegisters(bool Vector) {
if (Vector) {
if (ST->hasNEON())
return 16;
return 0;
}
if (ST->isThumb1Only())
return 8;
return 13;
}
unsigned getRegisterBitWidth(bool Vector) {
if (Vector) {
if (ST->hasNEON())
return 128;
return 0;
}
return 32;
}
unsigned getMaxInterleaveFactor() {
// These are out of order CPUs:
if (ST->isCortexA15() || ST->isSwift())
return 2;
return 1;
}
unsigned getShuffleCost(TTI::ShuffleKind Kind, Type *Tp, int Index,
Type *SubTp);
unsigned getCastInstrCost(unsigned Opcode, Type *Dst, Type *Src);
unsigned getCmpSelInstrCost(unsigned Opcode, Type *ValTy, Type *CondTy);
unsigned getVectorInstrCost(unsigned Opcode, Type *Val, unsigned Index);
unsigned getAddressComputationCost(Type *Val, bool IsComplex);
unsigned getArithmeticInstrCost(
unsigned Opcode, Type *Ty,
TTI::OperandValueKind Op1Info = TTI::OK_AnyValue,
TTI::OperandValueKind Op2Info = TTI::OK_AnyValue,
TTI::OperandValueProperties Opd1PropInfo = TTI::OP_None,
TTI::OperandValueProperties Opd2PropInfo = TTI::OP_None);
unsigned getMemoryOpCost(unsigned Opcode, Type *Src, unsigned Alignment,
unsigned AddressSpace);
/// @}
};
} // end anonymous namespace
ImmutablePass *
llvm::createARMTargetTransformInfoPass(const ARMBaseTargetMachine *TM) {
return new TargetTransformInfoWrapperPass(ARMTTIImpl(TM));
}
unsigned ARMTTIImpl::getIntImmCost(const APInt &Imm, Type *Ty) {
assert(Ty->isIntegerTy());
unsigned Bits = Ty->getPrimitiveSizeInBits();
if (Bits == 0 || Bits > 32)
return 4;
int32_t SImmVal = Imm.getSExtValue();
uint32_t ZImmVal = Imm.getZExtValue();
if (!ST->isThumb()) {
if ((SImmVal >= 0 && SImmVal < 65536) ||
(ARM_AM::getSOImmVal(ZImmVal) != -1) ||
(ARM_AM::getSOImmVal(~ZImmVal) != -1))
return 1;
return ST->hasV6T2Ops() ? 2 : 3;
}
if (ST->isThumb2()) {
if ((SImmVal >= 0 && SImmVal < 65536) ||
(ARM_AM::getT2SOImmVal(ZImmVal) != -1) ||
(ARM_AM::getT2SOImmVal(~ZImmVal) != -1))
return 1;
return ST->hasV6T2Ops() ? 2 : 3;
}
// Thumb1.
if (SImmVal >= 0 && SImmVal < 256)
return 1;
if ((~ZImmVal < 256) || ARM_AM::isThumbImmShiftedVal(ZImmVal))
return 2;
// Load from constantpool.
return 3;
}
unsigned ARMTTIImpl::getCastInstrCost(unsigned Opcode, Type *Dst, Type *Src) {
int ISD = TLI->InstructionOpcodeToISD(Opcode);
assert(ISD && "Invalid opcode");
// Single to/from double precision conversions.
static const CostTblEntry<MVT::SimpleValueType> NEONFltDblTbl[] = {
// Vector fptrunc/fpext conversions.
{ ISD::FP_ROUND, MVT::v2f64, 2 },
{ ISD::FP_EXTEND, MVT::v2f32, 2 },
{ ISD::FP_EXTEND, MVT::v4f32, 4 }
};
if (Src->isVectorTy() && ST->hasNEON() && (ISD == ISD::FP_ROUND ||
ISD == ISD::FP_EXTEND)) {
std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(Src);
int Idx = CostTableLookup(NEONFltDblTbl, ISD, LT.second);
if (Idx != -1)
return LT.first * NEONFltDblTbl[Idx].Cost;
}
EVT SrcTy = TLI->getValueType(Src);
EVT DstTy = TLI->getValueType(Dst);
if (!SrcTy.isSimple() || !DstTy.isSimple())
return BaseT::getCastInstrCost(Opcode, Dst, Src);
// Some arithmetic, load and store operations have specific instructions
// to cast up/down their types automatically at no extra cost.
// TODO: Get these tables to know at least what the related operations are.
static const TypeConversionCostTblEntry<MVT::SimpleValueType>
NEONVectorConversionTbl[] = {
{ ISD::SIGN_EXTEND, MVT::v4i32, MVT::v4i16, 0 },
{ ISD::ZERO_EXTEND, MVT::v4i32, MVT::v4i16, 0 },
{ ISD::SIGN_EXTEND, MVT::v2i64, MVT::v2i32, 1 },
{ ISD::ZERO_EXTEND, MVT::v2i64, MVT::v2i32, 1 },
{ ISD::TRUNCATE, MVT::v4i32, MVT::v4i64, 0 },
{ ISD::TRUNCATE, MVT::v4i16, MVT::v4i32, 1 },
// The number of vmovl instructions for the extension.
{ ISD::SIGN_EXTEND, MVT::v4i64, MVT::v4i16, 3 },
{ ISD::ZERO_EXTEND, MVT::v4i64, MVT::v4i16, 3 },
{ ISD::SIGN_EXTEND, MVT::v8i32, MVT::v8i8, 3 },
{ ISD::ZERO_EXTEND, MVT::v8i32, MVT::v8i8, 3 },
{ ISD::SIGN_EXTEND, MVT::v8i64, MVT::v8i8, 7 },
{ ISD::ZERO_EXTEND, MVT::v8i64, MVT::v8i8, 7 },
{ ISD::SIGN_EXTEND, MVT::v8i64, MVT::v8i16, 6 },
{ ISD::ZERO_EXTEND, MVT::v8i64, MVT::v8i16, 6 },
{ ISD::SIGN_EXTEND, MVT::v16i32, MVT::v16i8, 6 },
{ ISD::ZERO_EXTEND, MVT::v16i32, MVT::v16i8, 6 },
// Operations that we legalize using splitting.
{ ISD::TRUNCATE, MVT::v16i8, MVT::v16i32, 6 },
{ ISD::TRUNCATE, MVT::v8i8, MVT::v8i32, 3 },
// Vector float <-> i32 conversions.
{ ISD::SINT_TO_FP, MVT::v4f32, MVT::v4i32, 1 },
{ ISD::UINT_TO_FP, MVT::v4f32, MVT::v4i32, 1 },
{ ISD::SINT_TO_FP, MVT::v2f32, MVT::v2i8, 3 },
{ ISD::UINT_TO_FP, MVT::v2f32, MVT::v2i8, 3 },
{ ISD::SINT_TO_FP, MVT::v2f32, MVT::v2i16, 2 },
{ ISD::UINT_TO_FP, MVT::v2f32, MVT::v2i16, 2 },
{ ISD::SINT_TO_FP, MVT::v2f32, MVT::v2i32, 1 },
{ ISD::UINT_TO_FP, MVT::v2f32, MVT::v2i32, 1 },
{ ISD::SINT_TO_FP, MVT::v4f32, MVT::v4i1, 3 },
{ ISD::UINT_TO_FP, MVT::v4f32, MVT::v4i1, 3 },
{ ISD::SINT_TO_FP, MVT::v4f32, MVT::v4i8, 3 },
{ ISD::UINT_TO_FP, MVT::v4f32, MVT::v4i8, 3 },
{ ISD::SINT_TO_FP, MVT::v4f32, MVT::v4i16, 2 },
{ ISD::UINT_TO_FP, MVT::v4f32, MVT::v4i16, 2 },
{ ISD::SINT_TO_FP, MVT::v8f32, MVT::v8i16, 4 },
{ ISD::UINT_TO_FP, MVT::v8f32, MVT::v8i16, 4 },
{ ISD::SINT_TO_FP, MVT::v8f32, MVT::v8i32, 2 },
{ ISD::UINT_TO_FP, MVT::v8f32, MVT::v8i32, 2 },
{ ISD::SINT_TO_FP, MVT::v16f32, MVT::v16i16, 8 },
{ ISD::UINT_TO_FP, MVT::v16f32, MVT::v16i16, 8 },
{ ISD::SINT_TO_FP, MVT::v16f32, MVT::v16i32, 4 },
{ ISD::UINT_TO_FP, MVT::v16f32, MVT::v16i32, 4 },
{ ISD::FP_TO_SINT, MVT::v4i32, MVT::v4f32, 1 },
{ ISD::FP_TO_UINT, MVT::v4i32, MVT::v4f32, 1 },
{ ISD::FP_TO_SINT, MVT::v4i8, MVT::v4f32, 3 },
{ ISD::FP_TO_UINT, MVT::v4i8, MVT::v4f32, 3 },
{ ISD::FP_TO_SINT, MVT::v4i16, MVT::v4f32, 2 },
{ ISD::FP_TO_UINT, MVT::v4i16, MVT::v4f32, 2 },
// Vector double <-> i32 conversions.
{ ISD::SINT_TO_FP, MVT::v2f64, MVT::v2i32, 2 },
{ ISD::UINT_TO_FP, MVT::v2f64, MVT::v2i32, 2 },
{ ISD::SINT_TO_FP, MVT::v2f64, MVT::v2i8, 4 },
{ ISD::UINT_TO_FP, MVT::v2f64, MVT::v2i8, 4 },
{ ISD::SINT_TO_FP, MVT::v2f64, MVT::v2i16, 3 },
{ ISD::UINT_TO_FP, MVT::v2f64, MVT::v2i16, 3 },
{ ISD::SINT_TO_FP, MVT::v2f64, MVT::v2i32, 2 },
{ ISD::UINT_TO_FP, MVT::v2f64, MVT::v2i32, 2 },
{ ISD::FP_TO_SINT, MVT::v2i32, MVT::v2f64, 2 },
{ ISD::FP_TO_UINT, MVT::v2i32, MVT::v2f64, 2 },
{ ISD::FP_TO_SINT, MVT::v8i16, MVT::v8f32, 4 },
{ ISD::FP_TO_UINT, MVT::v8i16, MVT::v8f32, 4 },
{ ISD::FP_TO_SINT, MVT::v16i16, MVT::v16f32, 8 },
{ ISD::FP_TO_UINT, MVT::v16i16, MVT::v16f32, 8 }
};
if (SrcTy.isVector() && ST->hasNEON()) {
int Idx = ConvertCostTableLookup(NEONVectorConversionTbl, ISD,
DstTy.getSimpleVT(), SrcTy.getSimpleVT());
if (Idx != -1)
return NEONVectorConversionTbl[Idx].Cost;
}
// Scalar float to integer conversions.
static const TypeConversionCostTblEntry<MVT::SimpleValueType>
NEONFloatConversionTbl[] = {
{ ISD::FP_TO_SINT, MVT::i1, MVT::f32, 2 },
{ ISD::FP_TO_UINT, MVT::i1, MVT::f32, 2 },
{ ISD::FP_TO_SINT, MVT::i1, MVT::f64, 2 },
{ ISD::FP_TO_UINT, MVT::i1, MVT::f64, 2 },
{ ISD::FP_TO_SINT, MVT::i8, MVT::f32, 2 },
{ ISD::FP_TO_UINT, MVT::i8, MVT::f32, 2 },
{ ISD::FP_TO_SINT, MVT::i8, MVT::f64, 2 },
{ ISD::FP_TO_UINT, MVT::i8, MVT::f64, 2 },
{ ISD::FP_TO_SINT, MVT::i16, MVT::f32, 2 },
{ ISD::FP_TO_UINT, MVT::i16, MVT::f32, 2 },
{ ISD::FP_TO_SINT, MVT::i16, MVT::f64, 2 },
{ ISD::FP_TO_UINT, MVT::i16, MVT::f64, 2 },
{ ISD::FP_TO_SINT, MVT::i32, MVT::f32, 2 },
{ ISD::FP_TO_UINT, MVT::i32, MVT::f32, 2 },
{ ISD::FP_TO_SINT, MVT::i32, MVT::f64, 2 },
{ ISD::FP_TO_UINT, MVT::i32, MVT::f64, 2 },
{ ISD::FP_TO_SINT, MVT::i64, MVT::f32, 10 },
{ ISD::FP_TO_UINT, MVT::i64, MVT::f32, 10 },
{ ISD::FP_TO_SINT, MVT::i64, MVT::f64, 10 },
{ ISD::FP_TO_UINT, MVT::i64, MVT::f64, 10 }
};
if (SrcTy.isFloatingPoint() && ST->hasNEON()) {
int Idx = ConvertCostTableLookup(NEONFloatConversionTbl, ISD,
DstTy.getSimpleVT(), SrcTy.getSimpleVT());
if (Idx != -1)
return NEONFloatConversionTbl[Idx].Cost;
}
// Scalar integer to float conversions.
static const TypeConversionCostTblEntry<MVT::SimpleValueType>
NEONIntegerConversionTbl[] = {
{ ISD::SINT_TO_FP, MVT::f32, MVT::i1, 2 },
{ ISD::UINT_TO_FP, MVT::f32, MVT::i1, 2 },
{ ISD::SINT_TO_FP, MVT::f64, MVT::i1, 2 },
{ ISD::UINT_TO_FP, MVT::f64, MVT::i1, 2 },
{ ISD::SINT_TO_FP, MVT::f32, MVT::i8, 2 },
{ ISD::UINT_TO_FP, MVT::f32, MVT::i8, 2 },
{ ISD::SINT_TO_FP, MVT::f64, MVT::i8, 2 },
{ ISD::UINT_TO_FP, MVT::f64, MVT::i8, 2 },
{ ISD::SINT_TO_FP, MVT::f32, MVT::i16, 2 },
{ ISD::UINT_TO_FP, MVT::f32, MVT::i16, 2 },
{ ISD::SINT_TO_FP, MVT::f64, MVT::i16, 2 },
{ ISD::UINT_TO_FP, MVT::f64, MVT::i16, 2 },
{ ISD::SINT_TO_FP, MVT::f32, MVT::i32, 2 },
{ ISD::UINT_TO_FP, MVT::f32, MVT::i32, 2 },
{ ISD::SINT_TO_FP, MVT::f64, MVT::i32, 2 },
{ ISD::UINT_TO_FP, MVT::f64, MVT::i32, 2 },
{ ISD::SINT_TO_FP, MVT::f32, MVT::i64, 10 },
{ ISD::UINT_TO_FP, MVT::f32, MVT::i64, 10 },
{ ISD::SINT_TO_FP, MVT::f64, MVT::i64, 10 },
{ ISD::UINT_TO_FP, MVT::f64, MVT::i64, 10 }
};
if (SrcTy.isInteger() && ST->hasNEON()) {
int Idx = ConvertCostTableLookup(NEONIntegerConversionTbl, ISD,
DstTy.getSimpleVT(), SrcTy.getSimpleVT());
if (Idx != -1)
return NEONIntegerConversionTbl[Idx].Cost;
}
// Scalar integer conversion costs.
static const TypeConversionCostTblEntry<MVT::SimpleValueType>
ARMIntegerConversionTbl[] = {
// i16 -> i64 requires two dependent operations.
{ ISD::SIGN_EXTEND, MVT::i64, MVT::i16, 2 },
// Truncates on i64 are assumed to be free.
{ ISD::TRUNCATE, MVT::i32, MVT::i64, 0 },
{ ISD::TRUNCATE, MVT::i16, MVT::i64, 0 },
{ ISD::TRUNCATE, MVT::i8, MVT::i64, 0 },
{ ISD::TRUNCATE, MVT::i1, MVT::i64, 0 }
};
if (SrcTy.isInteger()) {
int Idx = ConvertCostTableLookup(ARMIntegerConversionTbl, ISD,
DstTy.getSimpleVT(), SrcTy.getSimpleVT());
if (Idx != -1)
return ARMIntegerConversionTbl[Idx].Cost;
}
return BaseT::getCastInstrCost(Opcode, Dst, Src);
}
unsigned ARMTTIImpl::getVectorInstrCost(unsigned Opcode, Type *ValTy,
unsigned Index) {
// Penalize inserting into an D-subregister. We end up with a three times
// lower estimated throughput on swift.
if (ST->isSwift() &&
Opcode == Instruction::InsertElement &&
ValTy->isVectorTy() &&
ValTy->getScalarSizeInBits() <= 32)
return 3;
// Cross-class copies are expensive on many microarchitectures,
// so assume they are expensive by default.
if ((Opcode == Instruction::InsertElement ||
Opcode == Instruction::ExtractElement) &&
ValTy->getVectorElementType()->isIntegerTy())
return 3;
return BaseT::getVectorInstrCost(Opcode, ValTy, Index);
}
unsigned ARMTTIImpl::getCmpSelInstrCost(unsigned Opcode, Type *ValTy,
Type *CondTy) {
int ISD = TLI->InstructionOpcodeToISD(Opcode);
// On NEON a a vector select gets lowered to vbsl.
if (ST->hasNEON() && ValTy->isVectorTy() && ISD == ISD::SELECT) {
// Lowering of some vector selects is currently far from perfect.
static const TypeConversionCostTblEntry<MVT::SimpleValueType>
NEONVectorSelectTbl[] = {
{ ISD::SELECT, MVT::v16i1, MVT::v16i16, 2*16 + 1 + 3*1 + 4*1 },
{ ISD::SELECT, MVT::v8i1, MVT::v8i32, 4*8 + 1*3 + 1*4 + 1*2 },
{ ISD::SELECT, MVT::v16i1, MVT::v16i32, 4*16 + 1*6 + 1*8 + 1*4 },
{ ISD::SELECT, MVT::v4i1, MVT::v4i64, 4*4 + 1*2 + 1 },
{ ISD::SELECT, MVT::v8i1, MVT::v8i64, 50 },
{ ISD::SELECT, MVT::v16i1, MVT::v16i64, 100 }
};
EVT SelCondTy = TLI->getValueType(CondTy);
EVT SelValTy = TLI->getValueType(ValTy);
if (SelCondTy.isSimple() && SelValTy.isSimple()) {
int Idx = ConvertCostTableLookup(NEONVectorSelectTbl, ISD,
SelCondTy.getSimpleVT(),
SelValTy.getSimpleVT());
if (Idx != -1)
return NEONVectorSelectTbl[Idx].Cost;
}
std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(ValTy);
return LT.first;
}
return BaseT::getCmpSelInstrCost(Opcode, ValTy, CondTy);
}
unsigned ARMTTIImpl::getAddressComputationCost(Type *Ty, bool IsComplex) {
// Address computations in vectorized code with non-consecutive addresses will
// likely result in more instructions compared to scalar code where the
// computation can more often be merged into the index mode. The resulting
// extra micro-ops can significantly decrease throughput.
unsigned NumVectorInstToHideOverhead = 10;
if (Ty->isVectorTy() && IsComplex)
return NumVectorInstToHideOverhead;
// In many cases the address computation is not merged into the instruction
// addressing mode.
return 1;
}
unsigned ARMTTIImpl::getShuffleCost(TTI::ShuffleKind Kind, Type *Tp, int Index,
Type *SubTp) {
// We only handle costs of reverse and alternate shuffles for now.
if (Kind != TTI::SK_Reverse && Kind != TTI::SK_Alternate)
return BaseT::getShuffleCost(Kind, Tp, Index, SubTp);
if (Kind == TTI::SK_Reverse) {
static const CostTblEntry<MVT::SimpleValueType> NEONShuffleTbl[] = {
// Reverse shuffle cost one instruction if we are shuffling within a
// double word (vrev) or two if we shuffle a quad word (vrev, vext).
{ISD::VECTOR_SHUFFLE, MVT::v2i32, 1},
{ISD::VECTOR_SHUFFLE, MVT::v2f32, 1},
{ISD::VECTOR_SHUFFLE, MVT::v2i64, 1},
{ISD::VECTOR_SHUFFLE, MVT::v2f64, 1},
{ISD::VECTOR_SHUFFLE, MVT::v4i32, 2},
{ISD::VECTOR_SHUFFLE, MVT::v4f32, 2},
{ISD::VECTOR_SHUFFLE, MVT::v8i16, 2},
{ISD::VECTOR_SHUFFLE, MVT::v16i8, 2}};
std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(Tp);
int Idx = CostTableLookup(NEONShuffleTbl, ISD::VECTOR_SHUFFLE, LT.second);
if (Idx == -1)
return BaseT::getShuffleCost(Kind, Tp, Index, SubTp);
return LT.first * NEONShuffleTbl[Idx].Cost;
}
if (Kind == TTI::SK_Alternate) {
static const CostTblEntry<MVT::SimpleValueType> NEONAltShuffleTbl[] = {
// Alt shuffle cost table for ARM. Cost is the number of instructions
// required to create the shuffled vector.
{ISD::VECTOR_SHUFFLE, MVT::v2f32, 1},
{ISD::VECTOR_SHUFFLE, MVT::v2i64, 1},
{ISD::VECTOR_SHUFFLE, MVT::v2f64, 1},
{ISD::VECTOR_SHUFFLE, MVT::v2i32, 1},
{ISD::VECTOR_SHUFFLE, MVT::v4i32, 2},
{ISD::VECTOR_SHUFFLE, MVT::v4f32, 2},
{ISD::VECTOR_SHUFFLE, MVT::v4i16, 2},
{ISD::VECTOR_SHUFFLE, MVT::v8i16, 16},
{ISD::VECTOR_SHUFFLE, MVT::v16i8, 32}};
std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(Tp);
int Idx =
CostTableLookup(NEONAltShuffleTbl, ISD::VECTOR_SHUFFLE, LT.second);
if (Idx == -1)
return BaseT::getShuffleCost(Kind, Tp, Index, SubTp);
return LT.first * NEONAltShuffleTbl[Idx].Cost;
}
return BaseT::getShuffleCost(Kind, Tp, Index, SubTp);
}
unsigned ARMTTIImpl::getArithmeticInstrCost(
unsigned Opcode, Type *Ty, TTI::OperandValueKind Op1Info,
TTI::OperandValueKind Op2Info, TTI::OperandValueProperties Opd1PropInfo,
TTI::OperandValueProperties Opd2PropInfo) {
int ISDOpcode = TLI->InstructionOpcodeToISD(Opcode);
std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(Ty);
const unsigned FunctionCallDivCost = 20;
const unsigned ReciprocalDivCost = 10;
static const CostTblEntry<MVT::SimpleValueType> CostTbl[] = {
// Division.
// These costs are somewhat random. Choose a cost of 20 to indicate that
// vectorizing devision (added function call) is going to be very expensive.
// Double registers types.
{ ISD::SDIV, MVT::v1i64, 1 * FunctionCallDivCost},
{ ISD::UDIV, MVT::v1i64, 1 * FunctionCallDivCost},
{ ISD::SREM, MVT::v1i64, 1 * FunctionCallDivCost},
{ ISD::UREM, MVT::v1i64, 1 * FunctionCallDivCost},
{ ISD::SDIV, MVT::v2i32, 2 * FunctionCallDivCost},
{ ISD::UDIV, MVT::v2i32, 2 * FunctionCallDivCost},
{ ISD::SREM, MVT::v2i32, 2 * FunctionCallDivCost},
{ ISD::UREM, MVT::v2i32, 2 * FunctionCallDivCost},
{ ISD::SDIV, MVT::v4i16, ReciprocalDivCost},
{ ISD::UDIV, MVT::v4i16, ReciprocalDivCost},
{ ISD::SREM, MVT::v4i16, 4 * FunctionCallDivCost},
{ ISD::UREM, MVT::v4i16, 4 * FunctionCallDivCost},
{ ISD::SDIV, MVT::v8i8, ReciprocalDivCost},
{ ISD::UDIV, MVT::v8i8, ReciprocalDivCost},
{ ISD::SREM, MVT::v8i8, 8 * FunctionCallDivCost},
{ ISD::UREM, MVT::v8i8, 8 * FunctionCallDivCost},
// Quad register types.
{ ISD::SDIV, MVT::v2i64, 2 * FunctionCallDivCost},
{ ISD::UDIV, MVT::v2i64, 2 * FunctionCallDivCost},
{ ISD::SREM, MVT::v2i64, 2 * FunctionCallDivCost},
{ ISD::UREM, MVT::v2i64, 2 * FunctionCallDivCost},
{ ISD::SDIV, MVT::v4i32, 4 * FunctionCallDivCost},
{ ISD::UDIV, MVT::v4i32, 4 * FunctionCallDivCost},
{ ISD::SREM, MVT::v4i32, 4 * FunctionCallDivCost},
{ ISD::UREM, MVT::v4i32, 4 * FunctionCallDivCost},
{ ISD::SDIV, MVT::v8i16, 8 * FunctionCallDivCost},
{ ISD::UDIV, MVT::v8i16, 8 * FunctionCallDivCost},
{ ISD::SREM, MVT::v8i16, 8 * FunctionCallDivCost},
{ ISD::UREM, MVT::v8i16, 8 * FunctionCallDivCost},
{ ISD::SDIV, MVT::v16i8, 16 * FunctionCallDivCost},
{ ISD::UDIV, MVT::v16i8, 16 * FunctionCallDivCost},
{ ISD::SREM, MVT::v16i8, 16 * FunctionCallDivCost},
{ ISD::UREM, MVT::v16i8, 16 * FunctionCallDivCost},
// Multiplication.
};
int Idx = -1;
if (ST->hasNEON())
Idx = CostTableLookup(CostTbl, ISDOpcode, LT.second);
if (Idx != -1)
return LT.first * CostTbl[Idx].Cost;
unsigned Cost = BaseT::getArithmeticInstrCost(Opcode, Ty, Op1Info, Op2Info,
Opd1PropInfo, Opd2PropInfo);
// This is somewhat of a hack. The problem that we are facing is that SROA
// creates a sequence of shift, and, or instructions to construct values.
// These sequences are recognized by the ISel and have zero-cost. Not so for
// the vectorized code. Because we have support for v2i64 but not i64 those
// sequences look particularly beneficial to vectorize.
// To work around this we increase the cost of v2i64 operations to make them
// seem less beneficial.
if (LT.second == MVT::v2i64 &&
Op2Info == TargetTransformInfo::OK_UniformConstantValue)
Cost += 4;
return Cost;
}
unsigned ARMTTIImpl::getMemoryOpCost(unsigned Opcode, Type *Src,
unsigned Alignment,
unsigned AddressSpace) {
std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(Src);
if (Src->isVectorTy() && Alignment != 16 &&
Src->getVectorElementType()->isDoubleTy()) {
// Unaligned loads/stores are extremely inefficient.
// We need 4 uops for vst.1/vld.1 vs 1uop for vldr/vstr.
return LT.first * 4;
}
return LT.first;
}
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