1//===- HexagonTargetTransformInfo.cpp - Hexagon specific TTI pass ---------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7/// \file
8/// This file implements a TargetTransformInfo analysis pass specific to the
9/// Hexagon target machine. It uses the target's detailed information to provide
10/// more precise answers to certain TTI queries, while letting the target
11/// independent and default TTI implementations handle the rest.
12///
13//===----------------------------------------------------------------------===//
14
15#include "HexagonTargetTransformInfo.h"
16#include "HexagonSubtarget.h"
17#include "llvm/Analysis/TargetTransformInfo.h"
18#include "llvm/CodeGen/ValueTypes.h"
19#include "llvm/IR/InstrTypes.h"
20#include "llvm/IR/Instructions.h"
21#include "llvm/IR/User.h"
22#include "llvm/Support/Casting.h"
23#include "llvm/Support/CommandLine.h"
24#include "llvm/Transforms/Utils/LoopPeel.h"
25#include "llvm/Transforms/Utils/UnrollLoop.h"
26
27using namespace llvm;
28
29#define DEBUG_TYPE "hexagontti"
30
31static cl::opt<bool> HexagonAutoHVX("hexagon-autohvx", cl::init(Val: false),
32 cl::Hidden, cl::desc("Enable loop vectorizer for HVX"));
33
34static cl::opt<bool> EnableV68FloatAutoHVX(
35 "force-hvx-float", cl::Hidden,
36 cl::desc("Enable auto-vectorization of floatint point types on v68."));
37
38static cl::opt<bool> EmitLookupTables("hexagon-emit-lookup-tables",
39 cl::init(Val: true), cl::Hidden,
40 cl::desc("Control lookup table emission on Hexagon target"));
41
42static cl::opt<bool> HexagonMaskedVMem("hexagon-masked-vmem", cl::init(Val: true),
43 cl::Hidden, cl::desc("Enable masked loads/stores for HVX"));
44
45// Constant "cost factor" to make floating point operations more expensive
46// in terms of vectorization cost. This isn't the best way, but it should
47// do. Ultimately, the cost should use cycles.
48static const unsigned FloatFactor = 4;
49
50bool HexagonTTIImpl::useHVX() const {
51 return ST.useHVXOps() && HexagonAutoHVX;
52}
53
54bool HexagonTTIImpl::isHVXVectorType(Type *Ty) const {
55 auto *VecTy = dyn_cast<VectorType>(Val: Ty);
56 if (!VecTy)
57 return false;
58 if (!ST.isTypeForHVX(VecTy))
59 return false;
60 if (ST.useHVXV69Ops() || !VecTy->getElementType()->isFloatingPointTy())
61 return true;
62 return ST.useHVXV68Ops() && EnableV68FloatAutoHVX;
63}
64
65unsigned HexagonTTIImpl::getTypeNumElements(Type *Ty) const {
66 if (auto *VTy = dyn_cast<FixedVectorType>(Val: Ty))
67 return VTy->getNumElements();
68 assert((Ty->isIntegerTy() || Ty->isFloatingPointTy()) &&
69 "Expecting scalar type");
70 return 1;
71}
72
73TargetTransformInfo::PopcntSupportKind
74HexagonTTIImpl::getPopcntSupport(unsigned IntTyWidthInBit) const {
75 // Return fast hardware support as every input < 64 bits will be promoted
76 // to 64 bits.
77 return TargetTransformInfo::PSK_FastHardware;
78}
79
80// The Hexagon target can unroll loops with run-time trip counts.
81void HexagonTTIImpl::getUnrollingPreferences(
82 Loop *L, ScalarEvolution &SE, TTI::UnrollingPreferences &UP,
83 OptimizationRemarkEmitter *ORE) const {
84 UP.Runtime = UP.Partial = true;
85}
86
87void HexagonTTIImpl::getPeelingPreferences(Loop *L, ScalarEvolution &SE,
88 TTI::PeelingPreferences &PP) const {
89 BaseT::getPeelingPreferences(L, SE, PP);
90 // Only try to peel innermost loops with small runtime trip counts.
91 if (L && L->isInnermost() && canPeel(L) &&
92 SE.getSmallConstantTripCount(L) == 0 &&
93 SE.getSmallConstantMaxTripCount(L) > 0 &&
94 SE.getSmallConstantMaxTripCount(L) <= 5) {
95 PP.PeelCount = 2;
96 }
97}
98
99TTI::AddressingModeKind
100HexagonTTIImpl::getPreferredAddressingMode(const Loop *L,
101 ScalarEvolution *SE) const {
102 return TTI::AMK_PostIndexed;
103}
104
105/// --- Vector TTI begin ---
106
107unsigned HexagonTTIImpl::getNumberOfRegisters(unsigned ClassID) const {
108 bool Vector = ClassID == 1;
109 if (Vector)
110 return useHVX() ? 32 : 0;
111 return 32;
112}
113
114unsigned HexagonTTIImpl::getMaxInterleaveFactor(ElementCount VF) const {
115 return useHVX() ? 2 : 1;
116}
117
118TypeSize
119HexagonTTIImpl::getRegisterBitWidth(TargetTransformInfo::RegisterKind K) const {
120 switch (K) {
121 case TargetTransformInfo::RGK_Scalar:
122 return TypeSize::getFixed(ExactSize: 32);
123 case TargetTransformInfo::RGK_FixedWidthVector:
124 return TypeSize::getFixed(ExactSize: getMinVectorRegisterBitWidth());
125 case TargetTransformInfo::RGK_ScalableVector:
126 return TypeSize::getScalable(MinimumSize: 0);
127 }
128
129 llvm_unreachable("Unsupported register kind");
130}
131
132unsigned HexagonTTIImpl::getMinVectorRegisterBitWidth() const {
133 return useHVX() ? ST.getVectorLength()*8 : 32;
134}
135
136ElementCount HexagonTTIImpl::getMinimumVF(unsigned ElemWidth,
137 bool IsScalable) const {
138 assert(!IsScalable && "Scalable VFs are not supported for Hexagon");
139 return ElementCount::getFixed(MinVal: (8 * ST.getVectorLength()) / ElemWidth);
140}
141
142InstructionCost
143HexagonTTIImpl::getCallInstrCost(Function *F, Type *RetTy, ArrayRef<Type *> Tys,
144 TTI::TargetCostKind CostKind) const {
145 return BaseT::getCallInstrCost(F, RetTy, Tys, CostKind);
146}
147
148InstructionCost
149HexagonTTIImpl::getIntrinsicInstrCost(const IntrinsicCostAttributes &ICA,
150 TTI::TargetCostKind CostKind) const {
151 if (ICA.getID() == Intrinsic::bswap) {
152 std::pair<InstructionCost, MVT> LT =
153 getTypeLegalizationCost(Ty: ICA.getReturnType());
154 return LT.first + 2;
155 }
156 return BaseT::getIntrinsicInstrCost(ICA, CostKind);
157}
158
159InstructionCost HexagonTTIImpl::getAddressComputationCost(Type *Tp,
160 ScalarEvolution *SE,
161 const SCEV *S) const {
162 return 0;
163}
164
165InstructionCost HexagonTTIImpl::getMemoryOpCost(unsigned Opcode, Type *Src,
166 Align Alignment,
167 unsigned AddressSpace,
168 TTI::TargetCostKind CostKind,
169 TTI::OperandValueInfo OpInfo,
170 const Instruction *I) const {
171 assert(Opcode == Instruction::Load || Opcode == Instruction::Store);
172 // TODO: Handle other cost kinds.
173 if (CostKind != TTI::TCK_RecipThroughput)
174 return 1;
175
176 if (Opcode == Instruction::Store)
177 return BaseT::getMemoryOpCost(Opcode, Src, Alignment, AddressSpace,
178 CostKind, OpInfo, I);
179
180 if (Src->isVectorTy()) {
181 VectorType *VecTy = cast<VectorType>(Val: Src);
182 unsigned VecWidth = VecTy->getPrimitiveSizeInBits().getFixedValue();
183 if (isHVXVectorType(Ty: VecTy)) {
184 unsigned RegWidth =
185 getRegisterBitWidth(K: TargetTransformInfo::RGK_FixedWidthVector)
186 .getFixedValue();
187 assert(RegWidth && "Non-zero vector register width expected");
188 // Cost of HVX loads.
189 if (VecWidth % RegWidth == 0)
190 return VecWidth / RegWidth;
191 // Cost of constructing HVX vector from scalar loads
192 const Align RegAlign(RegWidth / 8);
193 if (Alignment > RegAlign)
194 Alignment = RegAlign;
195 unsigned AlignWidth = 8 * Alignment.value();
196 unsigned NumLoads = alignTo(Value: VecWidth, Align: AlignWidth) / AlignWidth;
197 return 3 * NumLoads;
198 }
199
200 // Non-HVX vectors.
201 // Add extra cost for floating point types.
202 unsigned Cost =
203 VecTy->getElementType()->isFloatingPointTy() ? FloatFactor : 1;
204
205 // At this point unspecified alignment is considered as Align(1).
206 const Align BoundAlignment = std::min(a: Alignment, b: Align(8));
207 unsigned AlignWidth = 8 * BoundAlignment.value();
208 unsigned NumLoads = alignTo(Value: VecWidth, Align: AlignWidth) / AlignWidth;
209 if (Alignment == Align(4) || Alignment == Align(8))
210 return Cost * NumLoads;
211 // Loads of less than 32 bits will need extra inserts to compose a vector.
212 assert(BoundAlignment <= Align(8));
213 unsigned LogA = Log2(A: BoundAlignment);
214 return (3 - LogA) * Cost * NumLoads;
215 }
216
217 return BaseT::getMemoryOpCost(Opcode, Src, Alignment, AddressSpace, CostKind,
218 OpInfo, I);
219}
220
221InstructionCost
222HexagonTTIImpl::getMaskedMemoryOpCost(unsigned Opcode, Type *Src,
223 Align Alignment, unsigned AddressSpace,
224 TTI::TargetCostKind CostKind) const {
225 return BaseT::getMaskedMemoryOpCost(Opcode, DataTy: Src, Alignment, AddressSpace,
226 CostKind);
227}
228
229InstructionCost
230HexagonTTIImpl::getShuffleCost(TTI::ShuffleKind Kind, VectorType *DstTy,
231 VectorType *SrcTy, ArrayRef<int> Mask,
232 TTI::TargetCostKind CostKind, int Index,
233 VectorType *SubTp, ArrayRef<const Value *> Args,
234 const Instruction *CxtI) const {
235 return 1;
236}
237
238InstructionCost HexagonTTIImpl::getGatherScatterOpCost(
239 unsigned Opcode, Type *DataTy, const Value *Ptr, bool VariableMask,
240 Align Alignment, TTI::TargetCostKind CostKind, const Instruction *I) const {
241 return BaseT::getGatherScatterOpCost(Opcode, DataTy, Ptr, VariableMask,
242 Alignment, CostKind, I);
243}
244
245InstructionCost HexagonTTIImpl::getInterleavedMemoryOpCost(
246 unsigned Opcode, Type *VecTy, unsigned Factor, ArrayRef<unsigned> Indices,
247 Align Alignment, unsigned AddressSpace, TTI::TargetCostKind CostKind,
248 bool UseMaskForCond, bool UseMaskForGaps) const {
249 if (Indices.size() != Factor || UseMaskForCond || UseMaskForGaps)
250 return BaseT::getInterleavedMemoryOpCost(Opcode, VecTy, Factor, Indices,
251 Alignment, AddressSpace,
252 CostKind,
253 UseMaskForCond, UseMaskForGaps);
254 return getMemoryOpCost(Opcode, Src: VecTy, Alignment, AddressSpace, CostKind);
255}
256
257InstructionCost HexagonTTIImpl::getCmpSelInstrCost(
258 unsigned Opcode, Type *ValTy, Type *CondTy, CmpInst::Predicate VecPred,
259 TTI::TargetCostKind CostKind, TTI::OperandValueInfo Op1Info,
260 TTI::OperandValueInfo Op2Info, const Instruction *I) const {
261 if (ValTy->isVectorTy() && CostKind == TTI::TCK_RecipThroughput) {
262 if (!isHVXVectorType(Ty: ValTy) && ValTy->isFPOrFPVectorTy())
263 return InstructionCost::getMax();
264 std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(Ty: ValTy);
265 if (Opcode == Instruction::FCmp)
266 return LT.first + FloatFactor * getTypeNumElements(Ty: ValTy);
267 }
268 return BaseT::getCmpSelInstrCost(Opcode, ValTy, CondTy, VecPred, CostKind,
269 Op1Info, Op2Info, I);
270}
271
272InstructionCost HexagonTTIImpl::getArithmeticInstrCost(
273 unsigned Opcode, Type *Ty, TTI::TargetCostKind CostKind,
274 TTI::OperandValueInfo Op1Info, TTI::OperandValueInfo Op2Info,
275 ArrayRef<const Value *> Args, const Instruction *CxtI) const {
276 // TODO: Handle more cost kinds.
277 if (CostKind != TTI::TCK_RecipThroughput)
278 return BaseT::getArithmeticInstrCost(Opcode, Ty, CostKind, Opd1Info: Op1Info,
279 Opd2Info: Op2Info, Args, CxtI);
280
281 if (Ty->isVectorTy()) {
282 if (!isHVXVectorType(Ty) && Ty->isFPOrFPVectorTy())
283 return InstructionCost::getMax();
284 std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(Ty);
285 if (LT.second.isFloatingPoint())
286 return LT.first + FloatFactor * getTypeNumElements(Ty);
287 }
288 return BaseT::getArithmeticInstrCost(Opcode, Ty, CostKind, Opd1Info: Op1Info, Opd2Info: Op2Info,
289 Args, CxtI);
290}
291
292InstructionCost HexagonTTIImpl::getCastInstrCost(unsigned Opcode, Type *DstTy,
293 Type *SrcTy,
294 TTI::CastContextHint CCH,
295 TTI::TargetCostKind CostKind,
296 const Instruction *I) const {
297 auto isNonHVXFP = [this] (Type *Ty) {
298 return Ty->isVectorTy() && !isHVXVectorType(Ty) && Ty->isFPOrFPVectorTy();
299 };
300 if (isNonHVXFP(SrcTy) || isNonHVXFP(DstTy))
301 return InstructionCost::getMax();
302
303 if (SrcTy->isFPOrFPVectorTy() || DstTy->isFPOrFPVectorTy()) {
304 unsigned SrcN = SrcTy->isFPOrFPVectorTy() ? getTypeNumElements(Ty: SrcTy) : 0;
305 unsigned DstN = DstTy->isFPOrFPVectorTy() ? getTypeNumElements(Ty: DstTy) : 0;
306
307 std::pair<InstructionCost, MVT> SrcLT = getTypeLegalizationCost(Ty: SrcTy);
308 std::pair<InstructionCost, MVT> DstLT = getTypeLegalizationCost(Ty: DstTy);
309 InstructionCost Cost =
310 std::max(a: SrcLT.first, b: DstLT.first) + FloatFactor * (SrcN + DstN);
311 // TODO: Allow non-throughput costs that aren't binary.
312 if (CostKind != TTI::TCK_RecipThroughput)
313 return Cost == 0 ? 0 : 1;
314 return Cost;
315 }
316 return 1;
317}
318
319InstructionCost HexagonTTIImpl::getVectorInstrCost(unsigned Opcode, Type *Val,
320 TTI::TargetCostKind CostKind,
321 unsigned Index,
322 const Value *Op0,
323 const Value *Op1) const {
324 Type *ElemTy = Val->isVectorTy() ? cast<VectorType>(Val)->getElementType()
325 : Val;
326 if (Opcode == Instruction::InsertElement) {
327 // Need two rotations for non-zero index.
328 unsigned Cost = (Index != 0) ? 2 : 0;
329 if (ElemTy->isIntegerTy(Bitwidth: 32))
330 return Cost;
331 // If it's not a 32-bit value, there will need to be an extract.
332 return Cost + getVectorInstrCost(Opcode: Instruction::ExtractElement, Val, CostKind,
333 Index, Op0, Op1);
334 }
335
336 if (Opcode == Instruction::ExtractElement)
337 return 2;
338
339 return 1;
340}
341
342bool HexagonTTIImpl::isLegalMaskedStore(Type *DataType, Align /*Alignment*/,
343 unsigned /*AddressSpace*/) const {
344 // This function is called from scalarize-masked-mem-intrin, which runs
345 // in pre-isel. Use ST directly instead of calling isHVXVectorType.
346 return HexagonMaskedVMem && ST.isTypeForHVX(VecTy: DataType);
347}
348
349bool HexagonTTIImpl::isLegalMaskedLoad(Type *DataType, Align /*Alignment*/,
350 unsigned /*AddressSpace*/) const {
351 // This function is called from scalarize-masked-mem-intrin, which runs
352 // in pre-isel. Use ST directly instead of calling isHVXVectorType.
353 return HexagonMaskedVMem && ST.isTypeForHVX(VecTy: DataType);
354}
355
356/// --- Vector TTI end ---
357
358unsigned HexagonTTIImpl::getPrefetchDistance() const {
359 return ST.getL1PrefetchDistance();
360}
361
362unsigned HexagonTTIImpl::getCacheLineSize() const {
363 return ST.getL1CacheLineSize();
364}
365
366InstructionCost
367HexagonTTIImpl::getInstructionCost(const User *U,
368 ArrayRef<const Value *> Operands,
369 TTI::TargetCostKind CostKind) const {
370 auto isCastFoldedIntoLoad = [this](const CastInst *CI) -> bool {
371 if (!CI->isIntegerCast())
372 return false;
373 // Only extensions from an integer type shorter than 32-bit to i32
374 // can be folded into the load.
375 const DataLayout &DL = getDataLayout();
376 unsigned SBW = DL.getTypeSizeInBits(Ty: CI->getSrcTy());
377 unsigned DBW = DL.getTypeSizeInBits(Ty: CI->getDestTy());
378 if (DBW != 32 || SBW >= DBW)
379 return false;
380
381 const LoadInst *LI = dyn_cast<const LoadInst>(Val: CI->getOperand(i_nocapture: 0));
382 // Technically, this code could allow multiple uses of the load, and
383 // check if all the uses are the same extension operation, but this
384 // should be sufficient for most cases.
385 return LI && LI->hasOneUse();
386 };
387
388 if (const CastInst *CI = dyn_cast<const CastInst>(Val: U))
389 if (isCastFoldedIntoLoad(CI))
390 return TargetTransformInfo::TCC_Free;
391 return BaseT::getInstructionCost(U, Operands, CostKind);
392}
393
394bool HexagonTTIImpl::shouldBuildLookupTables() const {
395 return EmitLookupTables;
396}
397