1 //===- TargetTransformInfoImpl.h --------------------------------*- C++ -*-===//
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 //===----------------------------------------------------------------------===//
8 /// \file
9 /// This file provides helpers for the implementation of
10 /// a TargetTransformInfo-conforming class.
11 ///
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_ANALYSIS_TARGETTRANSFORMINFOIMPL_H
15 #define LLVM_ANALYSIS_TARGETTRANSFORMINFOIMPL_H
16 
17 #include "llvm/Analysis/ScalarEvolutionExpressions.h"
18 #include "llvm/Analysis/TargetTransformInfo.h"
19 #include "llvm/Analysis/VectorUtils.h"
20 #include "llvm/IR/CallSite.h"
21 #include "llvm/IR/DataLayout.h"
22 #include "llvm/IR/Function.h"
23 #include "llvm/IR/GetElementPtrTypeIterator.h"
24 #include "llvm/IR/Operator.h"
25 #include "llvm/IR/Type.h"
26 
27 namespace llvm {
28 
29 /// Base class for use as a mix-in that aids implementing
30 /// a TargetTransformInfo-compatible class.
31 class TargetTransformInfoImplBase {
32 protected:
33   typedef TargetTransformInfo TTI;
34 
35   const DataLayout &DL;
36 
37   explicit TargetTransformInfoImplBase(const DataLayout &DL) : DL(DL) {}
38 
39 public:
40   // Provide value semantics. MSVC requires that we spell all of these out.
41   TargetTransformInfoImplBase(const TargetTransformInfoImplBase &Arg)
42       : DL(Arg.DL) {}
43   TargetTransformInfoImplBase(TargetTransformInfoImplBase &&Arg) : DL(Arg.DL) {}
44 
45   const DataLayout &getDataLayout() const { return DL; }
46 
47   unsigned getOperationCost(unsigned Opcode, Type *Ty, Type *OpTy) {
48     switch (Opcode) {
49     default:
50       // By default, just classify everything as 'basic'.
51       return TTI::TCC_Basic;
52 
53     case Instruction::GetElementPtr:
54       llvm_unreachable("Use getGEPCost for GEP operations!");
55 
56     case Instruction::BitCast:
57       assert(OpTy && "Cast instructions must provide the operand type");
58       if (Ty == OpTy || (Ty->isPointerTy() && OpTy->isPointerTy()))
59         // Identity and pointer-to-pointer casts are free.
60         return TTI::TCC_Free;
61 
62       // Otherwise, the default basic cost is used.
63       return TTI::TCC_Basic;
64 
65     case Instruction::FDiv:
66     case Instruction::FRem:
67     case Instruction::SDiv:
68     case Instruction::SRem:
69     case Instruction::UDiv:
70     case Instruction::URem:
71       return TTI::TCC_Expensive;
72 
73     case Instruction::IntToPtr: {
74       // An inttoptr cast is free so long as the input is a legal integer type
75       // which doesn't contain values outside the range of a pointer.
76       unsigned OpSize = OpTy->getScalarSizeInBits();
77       if (DL.isLegalInteger(OpSize) &&
78           OpSize <= DL.getPointerTypeSizeInBits(Ty))
79         return TTI::TCC_Free;
80 
81       // Otherwise it's not a no-op.
82       return TTI::TCC_Basic;
83     }
84     case Instruction::PtrToInt: {
85       // A ptrtoint cast is free so long as the result is large enough to store
86       // the pointer, and a legal integer type.
87       unsigned DestSize = Ty->getScalarSizeInBits();
88       if (DL.isLegalInteger(DestSize) &&
89           DestSize >= DL.getPointerTypeSizeInBits(OpTy))
90         return TTI::TCC_Free;
91 
92       // Otherwise it's not a no-op.
93       return TTI::TCC_Basic;
94     }
95     case Instruction::Trunc:
96       // trunc to a native type is free (assuming the target has compare and
97       // shift-right of the same width).
98       if (DL.isLegalInteger(DL.getTypeSizeInBits(Ty)))
99         return TTI::TCC_Free;
100 
101       return TTI::TCC_Basic;
102     }
103   }
104 
105   int getGEPCost(Type *PointeeType, const Value *Ptr,
106                  ArrayRef<const Value *> Operands) {
107     // In the basic model, we just assume that all-constant GEPs will be folded
108     // into their uses via addressing modes.
109     for (unsigned Idx = 0, Size = Operands.size(); Idx != Size; ++Idx)
110       if (!isa<Constant>(Operands[Idx]))
111         return TTI::TCC_Basic;
112 
113     return TTI::TCC_Free;
114   }
115 
116   unsigned getEstimatedNumberOfCaseClusters(const SwitchInst &SI,
117                                             unsigned &JTSize) {
118     JTSize = 0;
119     return SI.getNumCases();
120   }
121 
122   int getExtCost(const Instruction *I, const Value *Src) {
123     return TTI::TCC_Basic;
124   }
125 
126   unsigned getCallCost(FunctionType *FTy, int NumArgs, const User *U) {
127     assert(FTy && "FunctionType must be provided to this routine.");
128 
129     // The target-independent implementation just measures the size of the
130     // function by approximating that each argument will take on average one
131     // instruction to prepare.
132 
133     if (NumArgs < 0)
134       // Set the argument number to the number of explicit arguments in the
135       // function.
136       NumArgs = FTy->getNumParams();
137 
138     return TTI::TCC_Basic * (NumArgs + 1);
139   }
140 
141   unsigned getInliningThresholdMultiplier() { return 1; }
142 
143   int getInlinerVectorBonusPercent() { return 150; }
144 
145   unsigned getMemcpyCost(const Instruction *I) {
146     return TTI::TCC_Expensive;
147   }
148 
149   bool hasBranchDivergence() { return false; }
150 
151   bool isSourceOfDivergence(const Value *V) { return false; }
152 
153   bool isAlwaysUniform(const Value *V) { return false; }
154 
155   unsigned getFlatAddressSpace () {
156     return -1;
157   }
158 
159   bool isLoweredToCall(const Function *F) {
160     assert(F && "A concrete function must be provided to this routine.");
161 
162     // FIXME: These should almost certainly not be handled here, and instead
163     // handled with the help of TLI or the target itself. This was largely
164     // ported from existing analysis heuristics here so that such refactorings
165     // can take place in the future.
166 
167     if (F->isIntrinsic())
168       return false;
169 
170     if (F->hasLocalLinkage() || !F->hasName())
171       return true;
172 
173     StringRef Name = F->getName();
174 
175     // These will all likely lower to a single selection DAG node.
176     if (Name == "copysign" || Name == "copysignf" || Name == "copysignl" ||
177         Name == "fabs" || Name == "fabsf" || Name == "fabsl" || Name == "sin" ||
178         Name == "fmin" || Name == "fminf" || Name == "fminl" ||
179         Name == "fmax" || Name == "fmaxf" || Name == "fmaxl" ||
180         Name == "sinf" || Name == "sinl" || Name == "cos" || Name == "cosf" ||
181         Name == "cosl" || Name == "sqrt" || Name == "sqrtf" || Name == "sqrtl")
182       return false;
183 
184     // These are all likely to be optimized into something smaller.
185     if (Name == "pow" || Name == "powf" || Name == "powl" || Name == "exp2" ||
186         Name == "exp2l" || Name == "exp2f" || Name == "floor" ||
187         Name == "floorf" || Name == "ceil" || Name == "round" ||
188         Name == "ffs" || Name == "ffsl" || Name == "abs" || Name == "labs" ||
189         Name == "llabs")
190       return false;
191 
192     return true;
193   }
194 
195   bool isHardwareLoopProfitable(Loop *L, ScalarEvolution &SE,
196                                 AssumptionCache &AC,
197                                 TargetLibraryInfo *LibInfo,
198                                 HardwareLoopInfo &HWLoopInfo) {
199     return false;
200   }
201 
202   void getUnrollingPreferences(Loop *, ScalarEvolution &,
203                                TTI::UnrollingPreferences &) {}
204 
205   bool isLegalAddImmediate(int64_t Imm) { return false; }
206 
207   bool isLegalICmpImmediate(int64_t Imm) { return false; }
208 
209   bool isLegalAddressingMode(Type *Ty, GlobalValue *BaseGV, int64_t BaseOffset,
210                              bool HasBaseReg, int64_t Scale,
211                              unsigned AddrSpace, Instruction *I = nullptr) {
212     // Guess that only reg and reg+reg addressing is allowed. This heuristic is
213     // taken from the implementation of LSR.
214     return !BaseGV && BaseOffset == 0 && (Scale == 0 || Scale == 1);
215   }
216 
217   bool isLSRCostLess(TTI::LSRCost &C1, TTI::LSRCost &C2) {
218     return std::tie(C1.NumRegs, C1.AddRecCost, C1.NumIVMuls, C1.NumBaseAdds,
219                     C1.ScaleCost, C1.ImmCost, C1.SetupCost) <
220            std::tie(C2.NumRegs, C2.AddRecCost, C2.NumIVMuls, C2.NumBaseAdds,
221                     C2.ScaleCost, C2.ImmCost, C2.SetupCost);
222   }
223 
224   bool canMacroFuseCmp() { return false; }
225 
226   bool canSaveCmp(Loop *L, BranchInst **BI, ScalarEvolution *SE, LoopInfo *LI,
227                   DominatorTree *DT, AssumptionCache *AC,
228                   TargetLibraryInfo *LibInfo) {
229     return false;
230   }
231 
232   bool shouldFavorPostInc() const { return false; }
233 
234   bool shouldFavorBackedgeIndex(const Loop *L) const { return false; }
235 
236   bool isLegalMaskedStore(Type *DataType) { return false; }
237 
238   bool isLegalMaskedLoad(Type *DataType) { return false; }
239 
240   bool isLegalNTStore(Type *DataType, unsigned Alignment) {
241     // By default, assume nontemporal memory stores are available for stores
242     // that are aligned and have a size that is a power of 2.
243     unsigned DataSize = DL.getTypeStoreSize(DataType);
244     return Alignment >= DataSize && isPowerOf2_32(DataSize);
245   }
246 
247   bool isLegalNTLoad(Type *DataType, unsigned Alignment) {
248     // By default, assume nontemporal memory loads are available for loads that
249     // are aligned and have a size that is a power of 2.
250     unsigned DataSize = DL.getTypeStoreSize(DataType);
251     return Alignment >= DataSize && isPowerOf2_32(DataSize);
252   }
253 
254   bool isLegalMaskedScatter(Type *DataType) { return false; }
255 
256   bool isLegalMaskedGather(Type *DataType) { return false; }
257 
258   bool isLegalMaskedCompressStore(Type *DataType) { return false; }
259 
260   bool isLegalMaskedExpandLoad(Type *DataType) { return false; }
261 
262   bool hasDivRemOp(Type *DataType, bool IsSigned) { return false; }
263 
264   bool hasVolatileVariant(Instruction *I, unsigned AddrSpace) { return false; }
265 
266   bool prefersVectorizedAddressing() { return true; }
267 
268   int getScalingFactorCost(Type *Ty, GlobalValue *BaseGV, int64_t BaseOffset,
269                            bool HasBaseReg, int64_t Scale, unsigned AddrSpace) {
270     // Guess that all legal addressing mode are free.
271     if (isLegalAddressingMode(Ty, BaseGV, BaseOffset, HasBaseReg,
272                               Scale, AddrSpace))
273       return 0;
274     return -1;
275   }
276 
277   bool LSRWithInstrQueries() { return false; }
278 
279   bool isTruncateFree(Type *Ty1, Type *Ty2) { return false; }
280 
281   bool isProfitableToHoist(Instruction *I) { return true; }
282 
283   bool useAA() { return false; }
284 
285   bool isTypeLegal(Type *Ty) { return false; }
286 
287   unsigned getJumpBufAlignment() { return 0; }
288 
289   unsigned getJumpBufSize() { return 0; }
290 
291   bool shouldBuildLookupTables() { return true; }
292   bool shouldBuildLookupTablesForConstant(Constant *C) { return true; }
293 
294   bool useColdCCForColdCall(Function &F) { return false; }
295 
296   unsigned getScalarizationOverhead(Type *Ty, bool Insert, bool Extract) {
297     return 0;
298   }
299 
300   unsigned getOperandsScalarizationOverhead(ArrayRef<const Value *> Args,
301                                             unsigned VF) { return 0; }
302 
303   bool supportsEfficientVectorElementLoadStore() { return false; }
304 
305   bool enableAggressiveInterleaving(bool LoopHasReductions) { return false; }
306 
307   TTI::MemCmpExpansionOptions enableMemCmpExpansion(bool OptSize,
308                                                     bool IsZeroCmp) const {
309     return {};
310   }
311 
312   bool enableInterleavedAccessVectorization() { return false; }
313 
314   bool enableMaskedInterleavedAccessVectorization() { return false; }
315 
316   bool isFPVectorizationPotentiallyUnsafe() { return false; }
317 
318   bool allowsMisalignedMemoryAccesses(LLVMContext &Context,
319                                       unsigned BitWidth,
320                                       unsigned AddressSpace,
321                                       unsigned Alignment,
322                                       bool *Fast) { return false; }
323 
324   TTI::PopcntSupportKind getPopcntSupport(unsigned IntTyWidthInBit) {
325     return TTI::PSK_Software;
326   }
327 
328   bool haveFastSqrt(Type *Ty) { return false; }
329 
330   bool isFCmpOrdCheaperThanFCmpZero(Type *Ty) { return true; }
331 
332   unsigned getFPOpCost(Type *Ty) { return TargetTransformInfo::TCC_Basic; }
333 
334   int getIntImmCodeSizeCost(unsigned Opcode, unsigned Idx, const APInt &Imm,
335                             Type *Ty) {
336     return 0;
337   }
338 
339   unsigned getIntImmCost(const APInt &Imm, Type *Ty) { return TTI::TCC_Basic; }
340 
341   unsigned getIntImmCost(unsigned Opcode, unsigned Idx, const APInt &Imm,
342                          Type *Ty) {
343     return TTI::TCC_Free;
344   }
345 
346   unsigned getIntImmCost(Intrinsic::ID IID, unsigned Idx, const APInt &Imm,
347                          Type *Ty) {
348     return TTI::TCC_Free;
349   }
350 
351   unsigned getNumberOfRegisters(bool Vector) { return 8; }
352 
353   unsigned getRegisterBitWidth(bool Vector) const { return 32; }
354 
355   unsigned getMinVectorRegisterBitWidth() { return 128; }
356 
357   bool shouldMaximizeVectorBandwidth(bool OptSize) const { return false; }
358 
359   unsigned getMinimumVF(unsigned ElemWidth) const { return 0; }
360 
361   bool
362   shouldConsiderAddressTypePromotion(const Instruction &I,
363                                      bool &AllowPromotionWithoutCommonHeader) {
364     AllowPromotionWithoutCommonHeader = false;
365     return false;
366   }
367 
368   unsigned getCacheLineSize() { return 0; }
369 
370   llvm::Optional<unsigned> getCacheSize(TargetTransformInfo::CacheLevel Level) {
371     switch (Level) {
372     case TargetTransformInfo::CacheLevel::L1D:
373       LLVM_FALLTHROUGH;
374     case TargetTransformInfo::CacheLevel::L2D:
375       return llvm::Optional<unsigned>();
376     }
377 
378     llvm_unreachable("Unknown TargetTransformInfo::CacheLevel");
379   }
380 
381   llvm::Optional<unsigned> getCacheAssociativity(
382     TargetTransformInfo::CacheLevel Level) {
383     switch (Level) {
384     case TargetTransformInfo::CacheLevel::L1D:
385       LLVM_FALLTHROUGH;
386     case TargetTransformInfo::CacheLevel::L2D:
387       return llvm::Optional<unsigned>();
388     }
389 
390     llvm_unreachable("Unknown TargetTransformInfo::CacheLevel");
391   }
392 
393   unsigned getPrefetchDistance() { return 0; }
394 
395   unsigned getMinPrefetchStride() { return 1; }
396 
397   unsigned getMaxPrefetchIterationsAhead() { return UINT_MAX; }
398 
399   unsigned getMaxInterleaveFactor(unsigned VF) { return 1; }
400 
401   unsigned getArithmeticInstrCost(unsigned Opcode, Type *Ty,
402                                   TTI::OperandValueKind Opd1Info,
403                                   TTI::OperandValueKind Opd2Info,
404                                   TTI::OperandValueProperties Opd1PropInfo,
405                                   TTI::OperandValueProperties Opd2PropInfo,
406                                   ArrayRef<const Value *> Args) {
407     return 1;
408   }
409 
410   unsigned getShuffleCost(TTI::ShuffleKind Kind, Type *Ty, int Index,
411                           Type *SubTp) {
412     return 1;
413   }
414 
415   unsigned getCastInstrCost(unsigned Opcode, Type *Dst, Type *Src,
416                             const Instruction *I) { return 1; }
417 
418   unsigned getExtractWithExtendCost(unsigned Opcode, Type *Dst,
419                                     VectorType *VecTy, unsigned Index) {
420     return 1;
421   }
422 
423   unsigned getCFInstrCost(unsigned Opcode) { return 1; }
424 
425   unsigned getCmpSelInstrCost(unsigned Opcode, Type *ValTy, Type *CondTy,
426                               const Instruction *I) {
427     return 1;
428   }
429 
430   unsigned getVectorInstrCost(unsigned Opcode, Type *Val, unsigned Index) {
431     return 1;
432   }
433 
434   unsigned getMemoryOpCost(unsigned Opcode, Type *Src, unsigned Alignment,
435                            unsigned AddressSpace, const Instruction *I) {
436     return 1;
437   }
438 
439   unsigned getMaskedMemoryOpCost(unsigned Opcode, Type *Src, unsigned Alignment,
440                                  unsigned AddressSpace) {
441     return 1;
442   }
443 
444   unsigned getGatherScatterOpCost(unsigned Opcode, Type *DataTy, Value *Ptr,
445                                   bool VariableMask,
446                                   unsigned Alignment) {
447     return 1;
448   }
449 
450   unsigned getInterleavedMemoryOpCost(unsigned Opcode, Type *VecTy,
451                                       unsigned Factor,
452                                       ArrayRef<unsigned> Indices,
453                                       unsigned Alignment, unsigned AddressSpace,
454                                       bool UseMaskForCond = false,
455                                       bool UseMaskForGaps = false) {
456     return 1;
457   }
458 
459   unsigned getIntrinsicInstrCost(Intrinsic::ID ID, Type *RetTy,
460                                  ArrayRef<Type *> Tys, FastMathFlags FMF,
461                                  unsigned ScalarizationCostPassed) {
462     return 1;
463   }
464   unsigned getIntrinsicInstrCost(Intrinsic::ID ID, Type *RetTy,
465             ArrayRef<Value *> Args, FastMathFlags FMF, unsigned VF) {
466     return 1;
467   }
468 
469   unsigned getCallInstrCost(Function *F, Type *RetTy, ArrayRef<Type *> Tys) {
470     return 1;
471   }
472 
473   unsigned getNumberOfParts(Type *Tp) { return 0; }
474 
475   unsigned getAddressComputationCost(Type *Tp, ScalarEvolution *,
476                                      const SCEV *) {
477     return 0;
478   }
479 
480   unsigned getArithmeticReductionCost(unsigned, Type *, bool) { return 1; }
481 
482   unsigned getMinMaxReductionCost(Type *, Type *, bool, bool) { return 1; }
483 
484   unsigned getCostOfKeepingLiveOverCall(ArrayRef<Type *> Tys) { return 0; }
485 
486   bool getTgtMemIntrinsic(IntrinsicInst *Inst, MemIntrinsicInfo &Info) {
487     return false;
488   }
489 
490   unsigned getAtomicMemIntrinsicMaxElementSize() const {
491     // Note for overrides: You must ensure for all element unordered-atomic
492     // memory intrinsics that all power-of-2 element sizes up to, and
493     // including, the return value of this method have a corresponding
494     // runtime lib call. These runtime lib call definitions can be found
495     // in RuntimeLibcalls.h
496     return 0;
497   }
498 
499   Value *getOrCreateResultFromMemIntrinsic(IntrinsicInst *Inst,
500                                            Type *ExpectedType) {
501     return nullptr;
502   }
503 
504   Type *getMemcpyLoopLoweringType(LLVMContext &Context, Value *Length,
505                                   unsigned SrcAlign, unsigned DestAlign) const {
506     return Type::getInt8Ty(Context);
507   }
508 
509   void getMemcpyLoopResidualLoweringType(SmallVectorImpl<Type *> &OpsOut,
510                                          LLVMContext &Context,
511                                          unsigned RemainingBytes,
512                                          unsigned SrcAlign,
513                                          unsigned DestAlign) const {
514     for (unsigned i = 0; i != RemainingBytes; ++i)
515       OpsOut.push_back(Type::getInt8Ty(Context));
516   }
517 
518   bool areInlineCompatible(const Function *Caller,
519                            const Function *Callee) const {
520     return (Caller->getFnAttribute("target-cpu") ==
521             Callee->getFnAttribute("target-cpu")) &&
522            (Caller->getFnAttribute("target-features") ==
523             Callee->getFnAttribute("target-features"));
524   }
525 
526   bool areFunctionArgsABICompatible(const Function *Caller, const Function *Callee,
527                                     SmallPtrSetImpl<Argument *> &Args) const {
528     return (Caller->getFnAttribute("target-cpu") ==
529             Callee->getFnAttribute("target-cpu")) &&
530            (Caller->getFnAttribute("target-features") ==
531             Callee->getFnAttribute("target-features"));
532   }
533 
534   bool isIndexedLoadLegal(TTI::MemIndexedMode Mode, Type *Ty,
535                           const DataLayout &DL) const {
536     return false;
537   }
538 
539   bool isIndexedStoreLegal(TTI::MemIndexedMode Mode, Type *Ty,
540                            const DataLayout &DL) const {
541     return false;
542   }
543 
544   unsigned getLoadStoreVecRegBitWidth(unsigned AddrSpace) const { return 128; }
545 
546   bool isLegalToVectorizeLoad(LoadInst *LI) const { return true; }
547 
548   bool isLegalToVectorizeStore(StoreInst *SI) const { return true; }
549 
550   bool isLegalToVectorizeLoadChain(unsigned ChainSizeInBytes,
551                                    unsigned Alignment,
552                                    unsigned AddrSpace) const {
553     return true;
554   }
555 
556   bool isLegalToVectorizeStoreChain(unsigned ChainSizeInBytes,
557                                     unsigned Alignment,
558                                     unsigned AddrSpace) const {
559     return true;
560   }
561 
562   unsigned getLoadVectorFactor(unsigned VF, unsigned LoadSize,
563                                unsigned ChainSizeInBytes,
564                                VectorType *VecTy) const {
565     return VF;
566   }
567 
568   unsigned getStoreVectorFactor(unsigned VF, unsigned StoreSize,
569                                 unsigned ChainSizeInBytes,
570                                 VectorType *VecTy) const {
571     return VF;
572   }
573 
574   bool useReductionIntrinsic(unsigned Opcode, Type *Ty,
575                              TTI::ReductionFlags Flags) const {
576     return false;
577   }
578 
579   bool shouldExpandReduction(const IntrinsicInst *II) const {
580     return true;
581   }
582 
583   unsigned getGISelRematGlobalCost() const {
584     return 1;
585   }
586 
587 protected:
588   // Obtain the minimum required size to hold the value (without the sign)
589   // In case of a vector it returns the min required size for one element.
590   unsigned minRequiredElementSize(const Value* Val, bool &isSigned) {
591     if (isa<ConstantDataVector>(Val) || isa<ConstantVector>(Val)) {
592       const auto* VectorValue = cast<Constant>(Val);
593 
594       // In case of a vector need to pick the max between the min
595       // required size for each element
596       auto *VT = cast<VectorType>(Val->getType());
597 
598       // Assume unsigned elements
599       isSigned = false;
600 
601       // The max required size is the total vector width divided by num
602       // of elements in the vector
603       unsigned MaxRequiredSize = VT->getBitWidth() / VT->getNumElements();
604 
605       unsigned MinRequiredSize = 0;
606       for(unsigned i = 0, e = VT->getNumElements(); i < e; ++i) {
607         if (auto* IntElement =
608               dyn_cast<ConstantInt>(VectorValue->getAggregateElement(i))) {
609           bool signedElement = IntElement->getValue().isNegative();
610           // Get the element min required size.
611           unsigned ElementMinRequiredSize =
612             IntElement->getValue().getMinSignedBits() - 1;
613           // In case one element is signed then all the vector is signed.
614           isSigned |= signedElement;
615           // Save the max required bit size between all the elements.
616           MinRequiredSize = std::max(MinRequiredSize, ElementMinRequiredSize);
617         }
618         else {
619           // not an int constant element
620           return MaxRequiredSize;
621         }
622       }
623       return MinRequiredSize;
624     }
625 
626     if (const auto* CI = dyn_cast<ConstantInt>(Val)) {
627       isSigned = CI->getValue().isNegative();
628       return CI->getValue().getMinSignedBits() - 1;
629     }
630 
631     if (const auto* Cast = dyn_cast<SExtInst>(Val)) {
632       isSigned = true;
633       return Cast->getSrcTy()->getScalarSizeInBits() - 1;
634     }
635 
636     if (const auto* Cast = dyn_cast<ZExtInst>(Val)) {
637       isSigned = false;
638       return Cast->getSrcTy()->getScalarSizeInBits();
639     }
640 
641     isSigned = false;
642     return Val->getType()->getScalarSizeInBits();
643   }
644 
645   bool isStridedAccess(const SCEV *Ptr) {
646     return Ptr && isa<SCEVAddRecExpr>(Ptr);
647   }
648 
649   const SCEVConstant *getConstantStrideStep(ScalarEvolution *SE,
650                                             const SCEV *Ptr) {
651     if (!isStridedAccess(Ptr))
652       return nullptr;
653     const SCEVAddRecExpr *AddRec = cast<SCEVAddRecExpr>(Ptr);
654     return dyn_cast<SCEVConstant>(AddRec->getStepRecurrence(*SE));
655   }
656 
657   bool isConstantStridedAccessLessThan(ScalarEvolution *SE, const SCEV *Ptr,
658                                        int64_t MergeDistance) {
659     const SCEVConstant *Step = getConstantStrideStep(SE, Ptr);
660     if (!Step)
661       return false;
662     APInt StrideVal = Step->getAPInt();
663     if (StrideVal.getBitWidth() > 64)
664       return false;
665     // FIXME: Need to take absolute value for negative stride case.
666     return StrideVal.getSExtValue() < MergeDistance;
667   }
668 };
669 
670 /// CRTP base class for use as a mix-in that aids implementing
671 /// a TargetTransformInfo-compatible class.
672 template <typename T>
673 class TargetTransformInfoImplCRTPBase : public TargetTransformInfoImplBase {
674 private:
675   typedef TargetTransformInfoImplBase BaseT;
676 
677 protected:
678   explicit TargetTransformInfoImplCRTPBase(const DataLayout &DL) : BaseT(DL) {}
679 
680 public:
681   using BaseT::getCallCost;
682 
683   unsigned getCallCost(const Function *F, int NumArgs, const User *U) {
684     assert(F && "A concrete function must be provided to this routine.");
685 
686     if (NumArgs < 0)
687       // Set the argument number to the number of explicit arguments in the
688       // function.
689       NumArgs = F->arg_size();
690 
691     if (Intrinsic::ID IID = F->getIntrinsicID()) {
692       FunctionType *FTy = F->getFunctionType();
693       SmallVector<Type *, 8> ParamTys(FTy->param_begin(), FTy->param_end());
694       return static_cast<T *>(this)
695           ->getIntrinsicCost(IID, FTy->getReturnType(), ParamTys, U);
696     }
697 
698     if (!static_cast<T *>(this)->isLoweredToCall(F))
699       return TTI::TCC_Basic; // Give a basic cost if it will be lowered
700                              // directly.
701 
702     return static_cast<T *>(this)->getCallCost(F->getFunctionType(), NumArgs, U);
703   }
704 
705   unsigned getCallCost(const Function *F, ArrayRef<const Value *> Arguments,
706                        const User *U) {
707     // Simply delegate to generic handling of the call.
708     // FIXME: We should use instsimplify or something else to catch calls which
709     // will constant fold with these arguments.
710     return static_cast<T *>(this)->getCallCost(F, Arguments.size(), U);
711   }
712 
713   using BaseT::getGEPCost;
714 
715   int getGEPCost(Type *PointeeType, const Value *Ptr,
716                  ArrayRef<const Value *> Operands) {
717     assert(PointeeType && Ptr && "can't get GEPCost of nullptr");
718     // TODO: will remove this when pointers have an opaque type.
719     assert(Ptr->getType()->getScalarType()->getPointerElementType() ==
720                PointeeType &&
721            "explicit pointee type doesn't match operand's pointee type");
722     auto *BaseGV = dyn_cast<GlobalValue>(Ptr->stripPointerCasts());
723     bool HasBaseReg = (BaseGV == nullptr);
724 
725     auto PtrSizeBits = DL.getPointerTypeSizeInBits(Ptr->getType());
726     APInt BaseOffset(PtrSizeBits, 0);
727     int64_t Scale = 0;
728 
729     auto GTI = gep_type_begin(PointeeType, Operands);
730     Type *TargetType = nullptr;
731 
732     // Handle the case where the GEP instruction has a single operand,
733     // the basis, therefore TargetType is a nullptr.
734     if (Operands.empty())
735       return !BaseGV ? TTI::TCC_Free : TTI::TCC_Basic;
736 
737     for (auto I = Operands.begin(); I != Operands.end(); ++I, ++GTI) {
738       TargetType = GTI.getIndexedType();
739       // We assume that the cost of Scalar GEP with constant index and the
740       // cost of Vector GEP with splat constant index are the same.
741       const ConstantInt *ConstIdx = dyn_cast<ConstantInt>(*I);
742       if (!ConstIdx)
743         if (auto Splat = getSplatValue(*I))
744           ConstIdx = dyn_cast<ConstantInt>(Splat);
745       if (StructType *STy = GTI.getStructTypeOrNull()) {
746         // For structures the index is always splat or scalar constant
747         assert(ConstIdx && "Unexpected GEP index");
748         uint64_t Field = ConstIdx->getZExtValue();
749         BaseOffset += DL.getStructLayout(STy)->getElementOffset(Field);
750       } else {
751         int64_t ElementSize = DL.getTypeAllocSize(GTI.getIndexedType());
752         if (ConstIdx) {
753           BaseOffset +=
754               ConstIdx->getValue().sextOrTrunc(PtrSizeBits) * ElementSize;
755         } else {
756           // Needs scale register.
757           if (Scale != 0)
758             // No addressing mode takes two scale registers.
759             return TTI::TCC_Basic;
760           Scale = ElementSize;
761         }
762       }
763     }
764 
765     if (static_cast<T *>(this)->isLegalAddressingMode(
766             TargetType, const_cast<GlobalValue *>(BaseGV),
767             BaseOffset.sextOrTrunc(64).getSExtValue(), HasBaseReg, Scale,
768             Ptr->getType()->getPointerAddressSpace()))
769       return TTI::TCC_Free;
770     return TTI::TCC_Basic;
771   }
772 
773   unsigned getIntrinsicCost(Intrinsic::ID IID, Type *RetTy,
774                             ArrayRef<Type *> ParamTys, const User *U) {
775     switch (IID) {
776     default:
777       // Intrinsics rarely (if ever) have normal argument setup constraints.
778       // Model them as having a basic instruction cost.
779       return TTI::TCC_Basic;
780 
781     // TODO: other libc intrinsics.
782     case Intrinsic::memcpy:
783       return static_cast<T *>(this)->getMemcpyCost(dyn_cast<Instruction>(U));
784 
785     case Intrinsic::annotation:
786     case Intrinsic::assume:
787     case Intrinsic::sideeffect:
788     case Intrinsic::dbg_declare:
789     case Intrinsic::dbg_value:
790     case Intrinsic::dbg_label:
791     case Intrinsic::invariant_start:
792     case Intrinsic::invariant_end:
793     case Intrinsic::launder_invariant_group:
794     case Intrinsic::strip_invariant_group:
795     case Intrinsic::is_constant:
796     case Intrinsic::lifetime_start:
797     case Intrinsic::lifetime_end:
798     case Intrinsic::objectsize:
799     case Intrinsic::ptr_annotation:
800     case Intrinsic::var_annotation:
801     case Intrinsic::experimental_gc_result:
802     case Intrinsic::experimental_gc_relocate:
803     case Intrinsic::coro_alloc:
804     case Intrinsic::coro_begin:
805     case Intrinsic::coro_free:
806     case Intrinsic::coro_end:
807     case Intrinsic::coro_frame:
808     case Intrinsic::coro_size:
809     case Intrinsic::coro_suspend:
810     case Intrinsic::coro_param:
811     case Intrinsic::coro_subfn_addr:
812       // These intrinsics don't actually represent code after lowering.
813       return TTI::TCC_Free;
814     }
815   }
816 
817   unsigned getIntrinsicCost(Intrinsic::ID IID, Type *RetTy,
818                             ArrayRef<const Value *> Arguments, const User *U) {
819     // Delegate to the generic intrinsic handling code. This mostly provides an
820     // opportunity for targets to (for example) special case the cost of
821     // certain intrinsics based on constants used as arguments.
822     SmallVector<Type *, 8> ParamTys;
823     ParamTys.reserve(Arguments.size());
824     for (unsigned Idx = 0, Size = Arguments.size(); Idx != Size; ++Idx)
825       ParamTys.push_back(Arguments[Idx]->getType());
826     return static_cast<T *>(this)->getIntrinsicCost(IID, RetTy, ParamTys, U);
827   }
828 
829   unsigned getUserCost(const User *U, ArrayRef<const Value *> Operands) {
830     if (isa<PHINode>(U))
831       return TTI::TCC_Free; // Model all PHI nodes as free.
832 
833     // Static alloca doesn't generate target instructions.
834     if (auto *A = dyn_cast<AllocaInst>(U))
835       if (A->isStaticAlloca())
836         return TTI::TCC_Free;
837 
838     if (const GEPOperator *GEP = dyn_cast<GEPOperator>(U)) {
839       return static_cast<T *>(this)->getGEPCost(GEP->getSourceElementType(),
840                                                 GEP->getPointerOperand(),
841                                                 Operands.drop_front());
842     }
843 
844     if (auto CS = ImmutableCallSite(U)) {
845       const Function *F = CS.getCalledFunction();
846       if (!F) {
847         // Just use the called value type.
848         Type *FTy = CS.getCalledValue()->getType()->getPointerElementType();
849         return static_cast<T *>(this)
850             ->getCallCost(cast<FunctionType>(FTy), CS.arg_size(), U);
851       }
852 
853       SmallVector<const Value *, 8> Arguments(CS.arg_begin(), CS.arg_end());
854       return static_cast<T *>(this)->getCallCost(F, Arguments, U);
855     }
856 
857     if (isa<SExtInst>(U) || isa<ZExtInst>(U) || isa<FPExtInst>(U))
858       // The old behaviour of generally treating extensions of icmp to be free
859       // has been removed. A target that needs it should override getUserCost().
860       return static_cast<T *>(this)->getExtCost(cast<Instruction>(U),
861                                                 Operands.back());
862 
863     return static_cast<T *>(this)->getOperationCost(
864         Operator::getOpcode(U), U->getType(),
865         U->getNumOperands() == 1 ? U->getOperand(0)->getType() : nullptr);
866   }
867 
868   int getInstructionLatency(const Instruction *I) {
869     SmallVector<const Value *, 4> Operands(I->value_op_begin(),
870                                            I->value_op_end());
871     if (getUserCost(I, Operands) == TTI::TCC_Free)
872       return 0;
873 
874     if (isa<LoadInst>(I))
875       return 4;
876 
877     Type *DstTy = I->getType();
878 
879     // Usually an intrinsic is a simple instruction.
880     // A real function call is much slower.
881     if (auto *CI = dyn_cast<CallInst>(I)) {
882       const Function *F = CI->getCalledFunction();
883       if (!F || static_cast<T *>(this)->isLoweredToCall(F))
884         return 40;
885       // Some intrinsics return a value and a flag, we use the value type
886       // to decide its latency.
887       if (StructType* StructTy = dyn_cast<StructType>(DstTy))
888         DstTy = StructTy->getElementType(0);
889       // Fall through to simple instructions.
890     }
891 
892     if (VectorType *VectorTy = dyn_cast<VectorType>(DstTy))
893       DstTy = VectorTy->getElementType();
894     if (DstTy->isFloatingPointTy())
895       return 3;
896 
897     return 1;
898   }
899 };
900 }
901 
902 #endif
903