1 //===- ARMTargetTransformInfo.cpp - ARM specific TTI ----------------------===//
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 
9 #include "ARMTargetTransformInfo.h"
10 #include "ARMSubtarget.h"
11 #include "MCTargetDesc/ARMAddressingModes.h"
12 #include "llvm/ADT/APInt.h"
13 #include "llvm/ADT/SmallVector.h"
14 #include "llvm/Analysis/LoopInfo.h"
15 #include "llvm/CodeGen/CostTable.h"
16 #include "llvm/CodeGen/ISDOpcodes.h"
17 #include "llvm/CodeGen/MachineValueType.h"
18 #include "llvm/CodeGen/ValueTypes.h"
19 #include "llvm/IR/BasicBlock.h"
20 #include "llvm/IR/DataLayout.h"
21 #include "llvm/IR/DerivedTypes.h"
22 #include "llvm/IR/Instruction.h"
23 #include "llvm/IR/Instructions.h"
24 #include "llvm/IR/IntrinsicInst.h"
25 #include "llvm/IR/Intrinsics.h"
26 #include "llvm/IR/IntrinsicsARM.h"
27 #include "llvm/IR/PatternMatch.h"
28 #include "llvm/IR/Type.h"
29 #include "llvm/Support/Casting.h"
30 #include "llvm/Support/KnownBits.h"
31 #include "llvm/Target/TargetMachine.h"
32 #include "llvm/TargetParser/SubtargetFeature.h"
33 #include "llvm/Transforms/InstCombine/InstCombiner.h"
34 #include "llvm/Transforms/Utils/Local.h"
35 #include "llvm/Transforms/Utils/LoopUtils.h"
36 #include "llvm/Transforms/Vectorize/LoopVectorizationLegality.h"
37 #include <algorithm>
38 #include <cassert>
39 #include <cstdint>
40 #include <optional>
41 #include <utility>
42 
43 using namespace llvm;
44 
45 #define DEBUG_TYPE "armtti"
46 
47 static cl::opt<bool> EnableMaskedLoadStores(
48   "enable-arm-maskedldst", cl::Hidden, cl::init(true),
49   cl::desc("Enable the generation of masked loads and stores"));
50 
51 static cl::opt<bool> DisableLowOverheadLoops(
52   "disable-arm-loloops", cl::Hidden, cl::init(false),
53   cl::desc("Disable the generation of low-overhead loops"));
54 
55 static cl::opt<bool>
56     AllowWLSLoops("allow-arm-wlsloops", cl::Hidden, cl::init(true),
57                   cl::desc("Enable the generation of WLS loops"));
58 
59 extern cl::opt<TailPredication::Mode> EnableTailPredication;
60 
61 extern cl::opt<bool> EnableMaskedGatherScatters;
62 
63 extern cl::opt<unsigned> MVEMaxSupportedInterleaveFactor;
64 
65 /// Convert a vector load intrinsic into a simple llvm load instruction.
66 /// This is beneficial when the underlying object being addressed comes
67 /// from a constant, since we get constant-folding for free.
simplifyNeonVld1(const IntrinsicInst & II,unsigned MemAlign,InstCombiner::BuilderTy & Builder)68 static Value *simplifyNeonVld1(const IntrinsicInst &II, unsigned MemAlign,
69                                InstCombiner::BuilderTy &Builder) {
70   auto *IntrAlign = dyn_cast<ConstantInt>(II.getArgOperand(1));
71 
72   if (!IntrAlign)
73     return nullptr;
74 
75   unsigned Alignment = IntrAlign->getLimitedValue() < MemAlign
76                            ? MemAlign
77                            : IntrAlign->getLimitedValue();
78 
79   if (!isPowerOf2_32(Alignment))
80     return nullptr;
81 
82   auto *BCastInst = Builder.CreateBitCast(II.getArgOperand(0),
83                                           PointerType::get(II.getType(), 0));
84   return Builder.CreateAlignedLoad(II.getType(), BCastInst, Align(Alignment));
85 }
86 
areInlineCompatible(const Function * Caller,const Function * Callee) const87 bool ARMTTIImpl::areInlineCompatible(const Function *Caller,
88                                      const Function *Callee) const {
89   const TargetMachine &TM = getTLI()->getTargetMachine();
90   const FeatureBitset &CallerBits =
91       TM.getSubtargetImpl(*Caller)->getFeatureBits();
92   const FeatureBitset &CalleeBits =
93       TM.getSubtargetImpl(*Callee)->getFeatureBits();
94 
95   // To inline a callee, all features not in the allowed list must match exactly.
96   bool MatchExact = (CallerBits & ~InlineFeaturesAllowed) ==
97                     (CalleeBits & ~InlineFeaturesAllowed);
98   // For features in the allowed list, the callee's features must be a subset of
99   // the callers'.
100   bool MatchSubset = ((CallerBits & CalleeBits) & InlineFeaturesAllowed) ==
101                      (CalleeBits & InlineFeaturesAllowed);
102   return MatchExact && MatchSubset;
103 }
104 
105 TTI::AddressingModeKind
getPreferredAddressingMode(const Loop * L,ScalarEvolution * SE) const106 ARMTTIImpl::getPreferredAddressingMode(const Loop *L,
107                                        ScalarEvolution *SE) const {
108   if (ST->hasMVEIntegerOps())
109     return TTI::AMK_PostIndexed;
110 
111   if (L->getHeader()->getParent()->hasOptSize())
112     return TTI::AMK_None;
113 
114   if (ST->isMClass() && ST->isThumb2() &&
115       L->getNumBlocks() == 1)
116     return TTI::AMK_PreIndexed;
117 
118   return TTI::AMK_None;
119 }
120 
121 std::optional<Instruction *>
instCombineIntrinsic(InstCombiner & IC,IntrinsicInst & II) const122 ARMTTIImpl::instCombineIntrinsic(InstCombiner &IC, IntrinsicInst &II) const {
123   using namespace PatternMatch;
124   Intrinsic::ID IID = II.getIntrinsicID();
125   switch (IID) {
126   default:
127     break;
128   case Intrinsic::arm_neon_vld1: {
129     Align MemAlign =
130         getKnownAlignment(II.getArgOperand(0), IC.getDataLayout(), &II,
131                           &IC.getAssumptionCache(), &IC.getDominatorTree());
132     if (Value *V = simplifyNeonVld1(II, MemAlign.value(), IC.Builder)) {
133       return IC.replaceInstUsesWith(II, V);
134     }
135     break;
136   }
137 
138   case Intrinsic::arm_neon_vld2:
139   case Intrinsic::arm_neon_vld3:
140   case Intrinsic::arm_neon_vld4:
141   case Intrinsic::arm_neon_vld2lane:
142   case Intrinsic::arm_neon_vld3lane:
143   case Intrinsic::arm_neon_vld4lane:
144   case Intrinsic::arm_neon_vst1:
145   case Intrinsic::arm_neon_vst2:
146   case Intrinsic::arm_neon_vst3:
147   case Intrinsic::arm_neon_vst4:
148   case Intrinsic::arm_neon_vst2lane:
149   case Intrinsic::arm_neon_vst3lane:
150   case Intrinsic::arm_neon_vst4lane: {
151     Align MemAlign =
152         getKnownAlignment(II.getArgOperand(0), IC.getDataLayout(), &II,
153                           &IC.getAssumptionCache(), &IC.getDominatorTree());
154     unsigned AlignArg = II.arg_size() - 1;
155     Value *AlignArgOp = II.getArgOperand(AlignArg);
156     MaybeAlign Align = cast<ConstantInt>(AlignArgOp)->getMaybeAlignValue();
157     if (Align && *Align < MemAlign) {
158       return IC.replaceOperand(
159           II, AlignArg,
160           ConstantInt::get(Type::getInt32Ty(II.getContext()), MemAlign.value(),
161                            false));
162     }
163     break;
164   }
165 
166   case Intrinsic::arm_mve_pred_i2v: {
167     Value *Arg = II.getArgOperand(0);
168     Value *ArgArg;
169     if (match(Arg, PatternMatch::m_Intrinsic<Intrinsic::arm_mve_pred_v2i>(
170                        PatternMatch::m_Value(ArgArg))) &&
171         II.getType() == ArgArg->getType()) {
172       return IC.replaceInstUsesWith(II, ArgArg);
173     }
174     Constant *XorMask;
175     if (match(Arg, m_Xor(PatternMatch::m_Intrinsic<Intrinsic::arm_mve_pred_v2i>(
176                              PatternMatch::m_Value(ArgArg)),
177                          PatternMatch::m_Constant(XorMask))) &&
178         II.getType() == ArgArg->getType()) {
179       if (auto *CI = dyn_cast<ConstantInt>(XorMask)) {
180         if (CI->getValue().trunc(16).isAllOnes()) {
181           auto TrueVector = IC.Builder.CreateVectorSplat(
182               cast<FixedVectorType>(II.getType())->getNumElements(),
183               IC.Builder.getTrue());
184           return BinaryOperator::Create(Instruction::Xor, ArgArg, TrueVector);
185         }
186       }
187     }
188     KnownBits ScalarKnown(32);
189     if (IC.SimplifyDemandedBits(&II, 0, APInt::getLowBitsSet(32, 16),
190                                 ScalarKnown, 0)) {
191       return &II;
192     }
193     break;
194   }
195   case Intrinsic::arm_mve_pred_v2i: {
196     Value *Arg = II.getArgOperand(0);
197     Value *ArgArg;
198     if (match(Arg, PatternMatch::m_Intrinsic<Intrinsic::arm_mve_pred_i2v>(
199                        PatternMatch::m_Value(ArgArg)))) {
200       return IC.replaceInstUsesWith(II, ArgArg);
201     }
202     if (!II.getMetadata(LLVMContext::MD_range)) {
203       Type *IntTy32 = Type::getInt32Ty(II.getContext());
204       Metadata *M[] = {
205           ConstantAsMetadata::get(ConstantInt::get(IntTy32, 0)),
206           ConstantAsMetadata::get(ConstantInt::get(IntTy32, 0x10000))};
207       II.setMetadata(LLVMContext::MD_range, MDNode::get(II.getContext(), M));
208       II.setMetadata(LLVMContext::MD_noundef,
209                      MDNode::get(II.getContext(), std::nullopt));
210       return &II;
211     }
212     break;
213   }
214   case Intrinsic::arm_mve_vadc:
215   case Intrinsic::arm_mve_vadc_predicated: {
216     unsigned CarryOp =
217         (II.getIntrinsicID() == Intrinsic::arm_mve_vadc_predicated) ? 3 : 2;
218     assert(II.getArgOperand(CarryOp)->getType()->getScalarSizeInBits() == 32 &&
219            "Bad type for intrinsic!");
220 
221     KnownBits CarryKnown(32);
222     if (IC.SimplifyDemandedBits(&II, CarryOp, APInt::getOneBitSet(32, 29),
223                                 CarryKnown)) {
224       return &II;
225     }
226     break;
227   }
228   case Intrinsic::arm_mve_vmldava: {
229     Instruction *I = cast<Instruction>(&II);
230     if (I->hasOneUse()) {
231       auto *User = cast<Instruction>(*I->user_begin());
232       Value *OpZ;
233       if (match(User, m_c_Add(m_Specific(I), m_Value(OpZ))) &&
234           match(I->getOperand(3), m_Zero())) {
235         Value *OpX = I->getOperand(4);
236         Value *OpY = I->getOperand(5);
237         Type *OpTy = OpX->getType();
238 
239         IC.Builder.SetInsertPoint(User);
240         Value *V =
241             IC.Builder.CreateIntrinsic(Intrinsic::arm_mve_vmldava, {OpTy},
242                                        {I->getOperand(0), I->getOperand(1),
243                                         I->getOperand(2), OpZ, OpX, OpY});
244 
245         IC.replaceInstUsesWith(*User, V);
246         return IC.eraseInstFromFunction(*User);
247       }
248     }
249     return std::nullopt;
250   }
251   }
252   return std::nullopt;
253 }
254 
simplifyDemandedVectorEltsIntrinsic(InstCombiner & IC,IntrinsicInst & II,APInt OrigDemandedElts,APInt & UndefElts,APInt & UndefElts2,APInt & UndefElts3,std::function<void (Instruction *,unsigned,APInt,APInt &)> SimplifyAndSetOp) const255 std::optional<Value *> ARMTTIImpl::simplifyDemandedVectorEltsIntrinsic(
256     InstCombiner &IC, IntrinsicInst &II, APInt OrigDemandedElts,
257     APInt &UndefElts, APInt &UndefElts2, APInt &UndefElts3,
258     std::function<void(Instruction *, unsigned, APInt, APInt &)>
259         SimplifyAndSetOp) const {
260 
261   // Compute the demanded bits for a narrowing MVE intrinsic. The TopOpc is the
262   // opcode specifying a Top/Bottom instruction, which can change between
263   // instructions.
264   auto SimplifyNarrowInstrTopBottom =[&](unsigned TopOpc) {
265     unsigned NumElts = cast<FixedVectorType>(II.getType())->getNumElements();
266     unsigned IsTop = cast<ConstantInt>(II.getOperand(TopOpc))->getZExtValue();
267 
268     // The only odd/even lanes of operand 0 will only be demanded depending
269     // on whether this is a top/bottom instruction.
270     APInt DemandedElts =
271         APInt::getSplat(NumElts, IsTop ? APInt::getLowBitsSet(2, 1)
272                                        : APInt::getHighBitsSet(2, 1));
273     SimplifyAndSetOp(&II, 0, OrigDemandedElts & DemandedElts, UndefElts);
274     // The other lanes will be defined from the inserted elements.
275     UndefElts &= APInt::getSplat(NumElts, IsTop ? APInt::getLowBitsSet(2, 1)
276                                                 : APInt::getHighBitsSet(2, 1));
277     return std::nullopt;
278   };
279 
280   switch (II.getIntrinsicID()) {
281   default:
282     break;
283   case Intrinsic::arm_mve_vcvt_narrow:
284     SimplifyNarrowInstrTopBottom(2);
285     break;
286   case Intrinsic::arm_mve_vqmovn:
287     SimplifyNarrowInstrTopBottom(4);
288     break;
289   case Intrinsic::arm_mve_vshrn:
290     SimplifyNarrowInstrTopBottom(7);
291     break;
292   }
293 
294   return std::nullopt;
295 }
296 
getIntImmCost(const APInt & Imm,Type * Ty,TTI::TargetCostKind CostKind)297 InstructionCost ARMTTIImpl::getIntImmCost(const APInt &Imm, Type *Ty,
298                                           TTI::TargetCostKind CostKind) {
299   assert(Ty->isIntegerTy());
300 
301  unsigned Bits = Ty->getPrimitiveSizeInBits();
302  if (Bits == 0 || Imm.getActiveBits() >= 64)
303    return 4;
304 
305   int64_t SImmVal = Imm.getSExtValue();
306   uint64_t ZImmVal = Imm.getZExtValue();
307   if (!ST->isThumb()) {
308     if ((SImmVal >= 0 && SImmVal < 65536) ||
309         (ARM_AM::getSOImmVal(ZImmVal) != -1) ||
310         (ARM_AM::getSOImmVal(~ZImmVal) != -1))
311       return 1;
312     return ST->hasV6T2Ops() ? 2 : 3;
313   }
314   if (ST->isThumb2()) {
315     if ((SImmVal >= 0 && SImmVal < 65536) ||
316         (ARM_AM::getT2SOImmVal(ZImmVal) != -1) ||
317         (ARM_AM::getT2SOImmVal(~ZImmVal) != -1))
318       return 1;
319     return ST->hasV6T2Ops() ? 2 : 3;
320   }
321   // Thumb1, any i8 imm cost 1.
322   if (Bits == 8 || (SImmVal >= 0 && SImmVal < 256))
323     return 1;
324   if ((~SImmVal < 256) || ARM_AM::isThumbImmShiftedVal(ZImmVal))
325     return 2;
326   // Load from constantpool.
327   return 3;
328 }
329 
330 // Constants smaller than 256 fit in the immediate field of
331 // Thumb1 instructions so we return a zero cost and 1 otherwise.
getIntImmCodeSizeCost(unsigned Opcode,unsigned Idx,const APInt & Imm,Type * Ty)332 InstructionCost ARMTTIImpl::getIntImmCodeSizeCost(unsigned Opcode, unsigned Idx,
333                                                   const APInt &Imm, Type *Ty) {
334   if (Imm.isNonNegative() && Imm.getLimitedValue() < 256)
335     return 0;
336 
337   return 1;
338 }
339 
340 // Checks whether Inst is part of a min(max()) or max(min()) pattern
341 // that will match to an SSAT instruction. Returns the instruction being
342 // saturated, or null if no saturation pattern was found.
isSSATMinMaxPattern(Instruction * Inst,const APInt & Imm)343 static Value *isSSATMinMaxPattern(Instruction *Inst, const APInt &Imm) {
344   Value *LHS, *RHS;
345   ConstantInt *C;
346   SelectPatternFlavor InstSPF = matchSelectPattern(Inst, LHS, RHS).Flavor;
347 
348   if (InstSPF == SPF_SMAX &&
349       PatternMatch::match(RHS, PatternMatch::m_ConstantInt(C)) &&
350       C->getValue() == Imm && Imm.isNegative() && Imm.isNegatedPowerOf2()) {
351 
352     auto isSSatMin = [&](Value *MinInst) {
353       if (isa<SelectInst>(MinInst)) {
354         Value *MinLHS, *MinRHS;
355         ConstantInt *MinC;
356         SelectPatternFlavor MinSPF =
357             matchSelectPattern(MinInst, MinLHS, MinRHS).Flavor;
358         if (MinSPF == SPF_SMIN &&
359             PatternMatch::match(MinRHS, PatternMatch::m_ConstantInt(MinC)) &&
360             MinC->getValue() == ((-Imm) - 1))
361           return true;
362       }
363       return false;
364     };
365 
366     if (isSSatMin(Inst->getOperand(1)))
367       return cast<Instruction>(Inst->getOperand(1))->getOperand(1);
368     if (Inst->hasNUses(2) &&
369         (isSSatMin(*Inst->user_begin()) || isSSatMin(*(++Inst->user_begin()))))
370       return Inst->getOperand(1);
371   }
372   return nullptr;
373 }
374 
375 // Look for a FP Saturation pattern, where the instruction can be simplified to
376 // a fptosi.sat. max(min(fptosi)). The constant in this case is always free.
isFPSatMinMaxPattern(Instruction * Inst,const APInt & Imm)377 static bool isFPSatMinMaxPattern(Instruction *Inst, const APInt &Imm) {
378   if (Imm.getBitWidth() != 64 ||
379       Imm != APInt::getHighBitsSet(64, 33)) // -2147483648
380     return false;
381   Value *FP = isSSATMinMaxPattern(Inst, Imm);
382   if (!FP && isa<ICmpInst>(Inst) && Inst->hasOneUse())
383     FP = isSSATMinMaxPattern(cast<Instruction>(*Inst->user_begin()), Imm);
384   if (!FP)
385     return false;
386   return isa<FPToSIInst>(FP);
387 }
388 
getIntImmCostInst(unsigned Opcode,unsigned Idx,const APInt & Imm,Type * Ty,TTI::TargetCostKind CostKind,Instruction * Inst)389 InstructionCost ARMTTIImpl::getIntImmCostInst(unsigned Opcode, unsigned Idx,
390                                               const APInt &Imm, Type *Ty,
391                                               TTI::TargetCostKind CostKind,
392                                               Instruction *Inst) {
393   // Division by a constant can be turned into multiplication, but only if we
394   // know it's constant. So it's not so much that the immediate is cheap (it's
395   // not), but that the alternative is worse.
396   // FIXME: this is probably unneeded with GlobalISel.
397   if ((Opcode == Instruction::SDiv || Opcode == Instruction::UDiv ||
398        Opcode == Instruction::SRem || Opcode == Instruction::URem) &&
399       Idx == 1)
400     return 0;
401 
402   // Leave any gep offsets for the CodeGenPrepare, which will do a better job at
403   // splitting any large offsets.
404   if (Opcode == Instruction::GetElementPtr && Idx != 0)
405     return 0;
406 
407   if (Opcode == Instruction::And) {
408     // UXTB/UXTH
409     if (Imm == 255 || Imm == 65535)
410       return 0;
411     // Conversion to BIC is free, and means we can use ~Imm instead.
412     return std::min(getIntImmCost(Imm, Ty, CostKind),
413                     getIntImmCost(~Imm, Ty, CostKind));
414   }
415 
416   if (Opcode == Instruction::Add)
417     // Conversion to SUB is free, and means we can use -Imm instead.
418     return std::min(getIntImmCost(Imm, Ty, CostKind),
419                     getIntImmCost(-Imm, Ty, CostKind));
420 
421   if (Opcode == Instruction::ICmp && Imm.isNegative() &&
422       Ty->getIntegerBitWidth() == 32) {
423     int64_t NegImm = -Imm.getSExtValue();
424     if (ST->isThumb2() && NegImm < 1<<12)
425       // icmp X, #-C -> cmn X, #C
426       return 0;
427     if (ST->isThumb() && NegImm < 1<<8)
428       // icmp X, #-C -> adds X, #C
429       return 0;
430   }
431 
432   // xor a, -1 can always be folded to MVN
433   if (Opcode == Instruction::Xor && Imm.isAllOnes())
434     return 0;
435 
436   // Ensures negative constant of min(max()) or max(min()) patterns that
437   // match to SSAT instructions don't get hoisted
438   if (Inst && ((ST->hasV6Ops() && !ST->isThumb()) || ST->isThumb2()) &&
439       Ty->getIntegerBitWidth() <= 32) {
440     if (isSSATMinMaxPattern(Inst, Imm) ||
441         (isa<ICmpInst>(Inst) && Inst->hasOneUse() &&
442          isSSATMinMaxPattern(cast<Instruction>(*Inst->user_begin()), Imm)))
443       return 0;
444   }
445 
446   if (Inst && ST->hasVFP2Base() && isFPSatMinMaxPattern(Inst, Imm))
447     return 0;
448 
449   // We can convert <= -1 to < 0, which is generally quite cheap.
450   if (Inst && Opcode == Instruction::ICmp && Idx == 1 && Imm.isAllOnes()) {
451     ICmpInst::Predicate Pred = cast<ICmpInst>(Inst)->getPredicate();
452     if (Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SLE)
453       return std::min(getIntImmCost(Imm, Ty, CostKind),
454                       getIntImmCost(Imm + 1, Ty, CostKind));
455   }
456 
457   return getIntImmCost(Imm, Ty, CostKind);
458 }
459 
getCFInstrCost(unsigned Opcode,TTI::TargetCostKind CostKind,const Instruction * I)460 InstructionCost ARMTTIImpl::getCFInstrCost(unsigned Opcode,
461                                            TTI::TargetCostKind CostKind,
462                                            const Instruction *I) {
463   if (CostKind == TTI::TCK_RecipThroughput &&
464       (ST->hasNEON() || ST->hasMVEIntegerOps())) {
465     // FIXME: The vectorizer is highly sensistive to the cost of these
466     // instructions, which suggests that it may be using the costs incorrectly.
467     // But, for now, just make them free to avoid performance regressions for
468     // vector targets.
469     return 0;
470   }
471   return BaseT::getCFInstrCost(Opcode, CostKind, I);
472 }
473 
getCastInstrCost(unsigned Opcode,Type * Dst,Type * Src,TTI::CastContextHint CCH,TTI::TargetCostKind CostKind,const Instruction * I)474 InstructionCost ARMTTIImpl::getCastInstrCost(unsigned Opcode, Type *Dst,
475                                              Type *Src,
476                                              TTI::CastContextHint CCH,
477                                              TTI::TargetCostKind CostKind,
478                                              const Instruction *I) {
479   int ISD = TLI->InstructionOpcodeToISD(Opcode);
480   assert(ISD && "Invalid opcode");
481 
482   // TODO: Allow non-throughput costs that aren't binary.
483   auto AdjustCost = [&CostKind](InstructionCost Cost) -> InstructionCost {
484     if (CostKind != TTI::TCK_RecipThroughput)
485       return Cost == 0 ? 0 : 1;
486     return Cost;
487   };
488   auto IsLegalFPType = [this](EVT VT) {
489     EVT EltVT = VT.getScalarType();
490     return (EltVT == MVT::f32 && ST->hasVFP2Base()) ||
491             (EltVT == MVT::f64 && ST->hasFP64()) ||
492             (EltVT == MVT::f16 && ST->hasFullFP16());
493   };
494 
495   EVT SrcTy = TLI->getValueType(DL, Src);
496   EVT DstTy = TLI->getValueType(DL, Dst);
497 
498   if (!SrcTy.isSimple() || !DstTy.isSimple())
499     return AdjustCost(
500         BaseT::getCastInstrCost(Opcode, Dst, Src, CCH, CostKind, I));
501 
502   // Extending masked load/Truncating masked stores is expensive because we
503   // currently don't split them. This means that we'll likely end up
504   // loading/storing each element individually (hence the high cost).
505   if ((ST->hasMVEIntegerOps() &&
506        (Opcode == Instruction::Trunc || Opcode == Instruction::ZExt ||
507         Opcode == Instruction::SExt)) ||
508       (ST->hasMVEFloatOps() &&
509        (Opcode == Instruction::FPExt || Opcode == Instruction::FPTrunc) &&
510        IsLegalFPType(SrcTy) && IsLegalFPType(DstTy)))
511     if (CCH == TTI::CastContextHint::Masked && DstTy.getSizeInBits() > 128)
512       return 2 * DstTy.getVectorNumElements() *
513              ST->getMVEVectorCostFactor(CostKind);
514 
515   // The extend of other kinds of load is free
516   if (CCH == TTI::CastContextHint::Normal ||
517       CCH == TTI::CastContextHint::Masked) {
518     static const TypeConversionCostTblEntry LoadConversionTbl[] = {
519         {ISD::SIGN_EXTEND, MVT::i32, MVT::i16, 0},
520         {ISD::ZERO_EXTEND, MVT::i32, MVT::i16, 0},
521         {ISD::SIGN_EXTEND, MVT::i32, MVT::i8, 0},
522         {ISD::ZERO_EXTEND, MVT::i32, MVT::i8, 0},
523         {ISD::SIGN_EXTEND, MVT::i16, MVT::i8, 0},
524         {ISD::ZERO_EXTEND, MVT::i16, MVT::i8, 0},
525         {ISD::SIGN_EXTEND, MVT::i64, MVT::i32, 1},
526         {ISD::ZERO_EXTEND, MVT::i64, MVT::i32, 1},
527         {ISD::SIGN_EXTEND, MVT::i64, MVT::i16, 1},
528         {ISD::ZERO_EXTEND, MVT::i64, MVT::i16, 1},
529         {ISD::SIGN_EXTEND, MVT::i64, MVT::i8, 1},
530         {ISD::ZERO_EXTEND, MVT::i64, MVT::i8, 1},
531     };
532     if (const auto *Entry = ConvertCostTableLookup(
533             LoadConversionTbl, ISD, DstTy.getSimpleVT(), SrcTy.getSimpleVT()))
534       return AdjustCost(Entry->Cost);
535 
536     static const TypeConversionCostTblEntry MVELoadConversionTbl[] = {
537         {ISD::SIGN_EXTEND, MVT::v4i32, MVT::v4i16, 0},
538         {ISD::ZERO_EXTEND, MVT::v4i32, MVT::v4i16, 0},
539         {ISD::SIGN_EXTEND, MVT::v4i32, MVT::v4i8, 0},
540         {ISD::ZERO_EXTEND, MVT::v4i32, MVT::v4i8, 0},
541         {ISD::SIGN_EXTEND, MVT::v8i16, MVT::v8i8, 0},
542         {ISD::ZERO_EXTEND, MVT::v8i16, MVT::v8i8, 0},
543         // The following extend from a legal type to an illegal type, so need to
544         // split the load. This introduced an extra load operation, but the
545         // extend is still "free".
546         {ISD::SIGN_EXTEND, MVT::v8i32, MVT::v8i16, 1},
547         {ISD::ZERO_EXTEND, MVT::v8i32, MVT::v8i16, 1},
548         {ISD::SIGN_EXTEND, MVT::v16i32, MVT::v16i8, 3},
549         {ISD::ZERO_EXTEND, MVT::v16i32, MVT::v16i8, 3},
550         {ISD::SIGN_EXTEND, MVT::v16i16, MVT::v16i8, 1},
551         {ISD::ZERO_EXTEND, MVT::v16i16, MVT::v16i8, 1},
552     };
553     if (SrcTy.isVector() && ST->hasMVEIntegerOps()) {
554       if (const auto *Entry =
555               ConvertCostTableLookup(MVELoadConversionTbl, ISD,
556                                      DstTy.getSimpleVT(), SrcTy.getSimpleVT()))
557         return Entry->Cost * ST->getMVEVectorCostFactor(CostKind);
558     }
559 
560     static const TypeConversionCostTblEntry MVEFLoadConversionTbl[] = {
561         // FPExtends are similar but also require the VCVT instructions.
562         {ISD::FP_EXTEND, MVT::v4f32, MVT::v4f16, 1},
563         {ISD::FP_EXTEND, MVT::v8f32, MVT::v8f16, 3},
564     };
565     if (SrcTy.isVector() && ST->hasMVEFloatOps()) {
566       if (const auto *Entry =
567               ConvertCostTableLookup(MVEFLoadConversionTbl, ISD,
568                                      DstTy.getSimpleVT(), SrcTy.getSimpleVT()))
569         return Entry->Cost * ST->getMVEVectorCostFactor(CostKind);
570     }
571 
572     // The truncate of a store is free. This is the mirror of extends above.
573     static const TypeConversionCostTblEntry MVEStoreConversionTbl[] = {
574         {ISD::TRUNCATE, MVT::v4i32, MVT::v4i16, 0},
575         {ISD::TRUNCATE, MVT::v4i32, MVT::v4i8, 0},
576         {ISD::TRUNCATE, MVT::v8i16, MVT::v8i8, 0},
577         {ISD::TRUNCATE, MVT::v8i32, MVT::v8i16, 1},
578         {ISD::TRUNCATE, MVT::v8i32, MVT::v8i8, 1},
579         {ISD::TRUNCATE, MVT::v16i32, MVT::v16i8, 3},
580         {ISD::TRUNCATE, MVT::v16i16, MVT::v16i8, 1},
581     };
582     if (SrcTy.isVector() && ST->hasMVEIntegerOps()) {
583       if (const auto *Entry =
584               ConvertCostTableLookup(MVEStoreConversionTbl, ISD,
585                                      SrcTy.getSimpleVT(), DstTy.getSimpleVT()))
586         return Entry->Cost * ST->getMVEVectorCostFactor(CostKind);
587     }
588 
589     static const TypeConversionCostTblEntry MVEFStoreConversionTbl[] = {
590         {ISD::FP_ROUND, MVT::v4f32, MVT::v4f16, 1},
591         {ISD::FP_ROUND, MVT::v8f32, MVT::v8f16, 3},
592     };
593     if (SrcTy.isVector() && ST->hasMVEFloatOps()) {
594       if (const auto *Entry =
595               ConvertCostTableLookup(MVEFStoreConversionTbl, ISD,
596                                      SrcTy.getSimpleVT(), DstTy.getSimpleVT()))
597         return Entry->Cost * ST->getMVEVectorCostFactor(CostKind);
598     }
599   }
600 
601   // NEON vector operations that can extend their inputs.
602   if ((ISD == ISD::SIGN_EXTEND || ISD == ISD::ZERO_EXTEND) &&
603       I && I->hasOneUse() && ST->hasNEON() && SrcTy.isVector()) {
604     static const TypeConversionCostTblEntry NEONDoubleWidthTbl[] = {
605       // vaddl
606       { ISD::ADD, MVT::v4i32, MVT::v4i16, 0 },
607       { ISD::ADD, MVT::v8i16, MVT::v8i8,  0 },
608       // vsubl
609       { ISD::SUB, MVT::v4i32, MVT::v4i16, 0 },
610       { ISD::SUB, MVT::v8i16, MVT::v8i8,  0 },
611       // vmull
612       { ISD::MUL, MVT::v4i32, MVT::v4i16, 0 },
613       { ISD::MUL, MVT::v8i16, MVT::v8i8,  0 },
614       // vshll
615       { ISD::SHL, MVT::v4i32, MVT::v4i16, 0 },
616       { ISD::SHL, MVT::v8i16, MVT::v8i8,  0 },
617     };
618 
619     auto *User = cast<Instruction>(*I->user_begin());
620     int UserISD = TLI->InstructionOpcodeToISD(User->getOpcode());
621     if (auto *Entry = ConvertCostTableLookup(NEONDoubleWidthTbl, UserISD,
622                                              DstTy.getSimpleVT(),
623                                              SrcTy.getSimpleVT())) {
624       return AdjustCost(Entry->Cost);
625     }
626   }
627 
628   // Single to/from double precision conversions.
629   if (Src->isVectorTy() && ST->hasNEON() &&
630       ((ISD == ISD::FP_ROUND && SrcTy.getScalarType() == MVT::f64 &&
631         DstTy.getScalarType() == MVT::f32) ||
632        (ISD == ISD::FP_EXTEND && SrcTy.getScalarType() == MVT::f32 &&
633         DstTy.getScalarType() == MVT::f64))) {
634     static const CostTblEntry NEONFltDblTbl[] = {
635         // Vector fptrunc/fpext conversions.
636         {ISD::FP_ROUND, MVT::v2f64, 2},
637         {ISD::FP_EXTEND, MVT::v2f32, 2},
638         {ISD::FP_EXTEND, MVT::v4f32, 4}};
639 
640     std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(Src);
641     if (const auto *Entry = CostTableLookup(NEONFltDblTbl, ISD, LT.second))
642       return AdjustCost(LT.first * Entry->Cost);
643   }
644 
645   // Some arithmetic, load and store operations have specific instructions
646   // to cast up/down their types automatically at no extra cost.
647   // TODO: Get these tables to know at least what the related operations are.
648   static const TypeConversionCostTblEntry NEONVectorConversionTbl[] = {
649     { ISD::SIGN_EXTEND, MVT::v4i32, MVT::v4i16, 1 },
650     { ISD::ZERO_EXTEND, MVT::v4i32, MVT::v4i16, 1 },
651     { ISD::SIGN_EXTEND, MVT::v2i64, MVT::v2i32, 1 },
652     { ISD::ZERO_EXTEND, MVT::v2i64, MVT::v2i32, 1 },
653     { ISD::TRUNCATE,    MVT::v4i32, MVT::v4i64, 0 },
654     { ISD::TRUNCATE,    MVT::v4i16, MVT::v4i32, 1 },
655 
656     // The number of vmovl instructions for the extension.
657     { ISD::SIGN_EXTEND, MVT::v8i16, MVT::v8i8,  1 },
658     { ISD::ZERO_EXTEND, MVT::v8i16, MVT::v8i8,  1 },
659     { ISD::SIGN_EXTEND, MVT::v4i32, MVT::v4i8,  2 },
660     { ISD::ZERO_EXTEND, MVT::v4i32, MVT::v4i8,  2 },
661     { ISD::SIGN_EXTEND, MVT::v2i64, MVT::v2i8,  3 },
662     { ISD::ZERO_EXTEND, MVT::v2i64, MVT::v2i8,  3 },
663     { ISD::SIGN_EXTEND, MVT::v2i64, MVT::v2i16, 2 },
664     { ISD::ZERO_EXTEND, MVT::v2i64, MVT::v2i16, 2 },
665     { ISD::SIGN_EXTEND, MVT::v4i64, MVT::v4i16, 3 },
666     { ISD::ZERO_EXTEND, MVT::v4i64, MVT::v4i16, 3 },
667     { ISD::SIGN_EXTEND, MVT::v8i32, MVT::v8i8, 3 },
668     { ISD::ZERO_EXTEND, MVT::v8i32, MVT::v8i8, 3 },
669     { ISD::SIGN_EXTEND, MVT::v8i64, MVT::v8i8, 7 },
670     { ISD::ZERO_EXTEND, MVT::v8i64, MVT::v8i8, 7 },
671     { ISD::SIGN_EXTEND, MVT::v8i64, MVT::v8i16, 6 },
672     { ISD::ZERO_EXTEND, MVT::v8i64, MVT::v8i16, 6 },
673     { ISD::SIGN_EXTEND, MVT::v16i32, MVT::v16i8, 6 },
674     { ISD::ZERO_EXTEND, MVT::v16i32, MVT::v16i8, 6 },
675 
676     // Operations that we legalize using splitting.
677     { ISD::TRUNCATE,    MVT::v16i8, MVT::v16i32, 6 },
678     { ISD::TRUNCATE,    MVT::v8i8, MVT::v8i32, 3 },
679 
680     // Vector float <-> i32 conversions.
681     { ISD::SINT_TO_FP,  MVT::v4f32, MVT::v4i32, 1 },
682     { ISD::UINT_TO_FP,  MVT::v4f32, MVT::v4i32, 1 },
683 
684     { ISD::SINT_TO_FP,  MVT::v2f32, MVT::v2i8, 3 },
685     { ISD::UINT_TO_FP,  MVT::v2f32, MVT::v2i8, 3 },
686     { ISD::SINT_TO_FP,  MVT::v2f32, MVT::v2i16, 2 },
687     { ISD::UINT_TO_FP,  MVT::v2f32, MVT::v2i16, 2 },
688     { ISD::SINT_TO_FP,  MVT::v2f32, MVT::v2i32, 1 },
689     { ISD::UINT_TO_FP,  MVT::v2f32, MVT::v2i32, 1 },
690     { ISD::SINT_TO_FP,  MVT::v4f32, MVT::v4i1, 3 },
691     { ISD::UINT_TO_FP,  MVT::v4f32, MVT::v4i1, 3 },
692     { ISD::SINT_TO_FP,  MVT::v4f32, MVT::v4i8, 3 },
693     { ISD::UINT_TO_FP,  MVT::v4f32, MVT::v4i8, 3 },
694     { ISD::SINT_TO_FP,  MVT::v4f32, MVT::v4i16, 2 },
695     { ISD::UINT_TO_FP,  MVT::v4f32, MVT::v4i16, 2 },
696     { ISD::SINT_TO_FP,  MVT::v8f32, MVT::v8i16, 4 },
697     { ISD::UINT_TO_FP,  MVT::v8f32, MVT::v8i16, 4 },
698     { ISD::SINT_TO_FP,  MVT::v8f32, MVT::v8i32, 2 },
699     { ISD::UINT_TO_FP,  MVT::v8f32, MVT::v8i32, 2 },
700     { ISD::SINT_TO_FP,  MVT::v16f32, MVT::v16i16, 8 },
701     { ISD::UINT_TO_FP,  MVT::v16f32, MVT::v16i16, 8 },
702     { ISD::SINT_TO_FP,  MVT::v16f32, MVT::v16i32, 4 },
703     { ISD::UINT_TO_FP,  MVT::v16f32, MVT::v16i32, 4 },
704 
705     { ISD::FP_TO_SINT,  MVT::v4i32, MVT::v4f32, 1 },
706     { ISD::FP_TO_UINT,  MVT::v4i32, MVT::v4f32, 1 },
707     { ISD::FP_TO_SINT,  MVT::v4i8, MVT::v4f32, 3 },
708     { ISD::FP_TO_UINT,  MVT::v4i8, MVT::v4f32, 3 },
709     { ISD::FP_TO_SINT,  MVT::v4i16, MVT::v4f32, 2 },
710     { ISD::FP_TO_UINT,  MVT::v4i16, MVT::v4f32, 2 },
711 
712     // Vector double <-> i32 conversions.
713     { ISD::SINT_TO_FP,  MVT::v2f64, MVT::v2i32, 2 },
714     { ISD::UINT_TO_FP,  MVT::v2f64, MVT::v2i32, 2 },
715 
716     { ISD::SINT_TO_FP,  MVT::v2f64, MVT::v2i8, 4 },
717     { ISD::UINT_TO_FP,  MVT::v2f64, MVT::v2i8, 4 },
718     { ISD::SINT_TO_FP,  MVT::v2f64, MVT::v2i16, 3 },
719     { ISD::UINT_TO_FP,  MVT::v2f64, MVT::v2i16, 3 },
720     { ISD::SINT_TO_FP,  MVT::v2f64, MVT::v2i32, 2 },
721     { ISD::UINT_TO_FP,  MVT::v2f64, MVT::v2i32, 2 },
722 
723     { ISD::FP_TO_SINT,  MVT::v2i32, MVT::v2f64, 2 },
724     { ISD::FP_TO_UINT,  MVT::v2i32, MVT::v2f64, 2 },
725     { ISD::FP_TO_SINT,  MVT::v8i16, MVT::v8f32, 4 },
726     { ISD::FP_TO_UINT,  MVT::v8i16, MVT::v8f32, 4 },
727     { ISD::FP_TO_SINT,  MVT::v16i16, MVT::v16f32, 8 },
728     { ISD::FP_TO_UINT,  MVT::v16i16, MVT::v16f32, 8 }
729   };
730 
731   if (SrcTy.isVector() && ST->hasNEON()) {
732     if (const auto *Entry = ConvertCostTableLookup(NEONVectorConversionTbl, ISD,
733                                                    DstTy.getSimpleVT(),
734                                                    SrcTy.getSimpleVT()))
735       return AdjustCost(Entry->Cost);
736   }
737 
738   // Scalar float to integer conversions.
739   static const TypeConversionCostTblEntry NEONFloatConversionTbl[] = {
740     { ISD::FP_TO_SINT,  MVT::i1, MVT::f32, 2 },
741     { ISD::FP_TO_UINT,  MVT::i1, MVT::f32, 2 },
742     { ISD::FP_TO_SINT,  MVT::i1, MVT::f64, 2 },
743     { ISD::FP_TO_UINT,  MVT::i1, MVT::f64, 2 },
744     { ISD::FP_TO_SINT,  MVT::i8, MVT::f32, 2 },
745     { ISD::FP_TO_UINT,  MVT::i8, MVT::f32, 2 },
746     { ISD::FP_TO_SINT,  MVT::i8, MVT::f64, 2 },
747     { ISD::FP_TO_UINT,  MVT::i8, MVT::f64, 2 },
748     { ISD::FP_TO_SINT,  MVT::i16, MVT::f32, 2 },
749     { ISD::FP_TO_UINT,  MVT::i16, MVT::f32, 2 },
750     { ISD::FP_TO_SINT,  MVT::i16, MVT::f64, 2 },
751     { ISD::FP_TO_UINT,  MVT::i16, MVT::f64, 2 },
752     { ISD::FP_TO_SINT,  MVT::i32, MVT::f32, 2 },
753     { ISD::FP_TO_UINT,  MVT::i32, MVT::f32, 2 },
754     { ISD::FP_TO_SINT,  MVT::i32, MVT::f64, 2 },
755     { ISD::FP_TO_UINT,  MVT::i32, MVT::f64, 2 },
756     { ISD::FP_TO_SINT,  MVT::i64, MVT::f32, 10 },
757     { ISD::FP_TO_UINT,  MVT::i64, MVT::f32, 10 },
758     { ISD::FP_TO_SINT,  MVT::i64, MVT::f64, 10 },
759     { ISD::FP_TO_UINT,  MVT::i64, MVT::f64, 10 }
760   };
761   if (SrcTy.isFloatingPoint() && ST->hasNEON()) {
762     if (const auto *Entry = ConvertCostTableLookup(NEONFloatConversionTbl, ISD,
763                                                    DstTy.getSimpleVT(),
764                                                    SrcTy.getSimpleVT()))
765       return AdjustCost(Entry->Cost);
766   }
767 
768   // Scalar integer to float conversions.
769   static const TypeConversionCostTblEntry NEONIntegerConversionTbl[] = {
770     { ISD::SINT_TO_FP,  MVT::f32, MVT::i1, 2 },
771     { ISD::UINT_TO_FP,  MVT::f32, MVT::i1, 2 },
772     { ISD::SINT_TO_FP,  MVT::f64, MVT::i1, 2 },
773     { ISD::UINT_TO_FP,  MVT::f64, MVT::i1, 2 },
774     { ISD::SINT_TO_FP,  MVT::f32, MVT::i8, 2 },
775     { ISD::UINT_TO_FP,  MVT::f32, MVT::i8, 2 },
776     { ISD::SINT_TO_FP,  MVT::f64, MVT::i8, 2 },
777     { ISD::UINT_TO_FP,  MVT::f64, MVT::i8, 2 },
778     { ISD::SINT_TO_FP,  MVT::f32, MVT::i16, 2 },
779     { ISD::UINT_TO_FP,  MVT::f32, MVT::i16, 2 },
780     { ISD::SINT_TO_FP,  MVT::f64, MVT::i16, 2 },
781     { ISD::UINT_TO_FP,  MVT::f64, MVT::i16, 2 },
782     { ISD::SINT_TO_FP,  MVT::f32, MVT::i32, 2 },
783     { ISD::UINT_TO_FP,  MVT::f32, MVT::i32, 2 },
784     { ISD::SINT_TO_FP,  MVT::f64, MVT::i32, 2 },
785     { ISD::UINT_TO_FP,  MVT::f64, MVT::i32, 2 },
786     { ISD::SINT_TO_FP,  MVT::f32, MVT::i64, 10 },
787     { ISD::UINT_TO_FP,  MVT::f32, MVT::i64, 10 },
788     { ISD::SINT_TO_FP,  MVT::f64, MVT::i64, 10 },
789     { ISD::UINT_TO_FP,  MVT::f64, MVT::i64, 10 }
790   };
791 
792   if (SrcTy.isInteger() && ST->hasNEON()) {
793     if (const auto *Entry = ConvertCostTableLookup(NEONIntegerConversionTbl,
794                                                    ISD, DstTy.getSimpleVT(),
795                                                    SrcTy.getSimpleVT()))
796       return AdjustCost(Entry->Cost);
797   }
798 
799   // MVE extend costs, taken from codegen tests. i8->i16 or i16->i32 is one
800   // instruction, i8->i32 is two. i64 zexts are an VAND with a constant, sext
801   // are linearised so take more.
802   static const TypeConversionCostTblEntry MVEVectorConversionTbl[] = {
803     { ISD::SIGN_EXTEND, MVT::v8i16, MVT::v8i8, 1 },
804     { ISD::ZERO_EXTEND, MVT::v8i16, MVT::v8i8, 1 },
805     { ISD::SIGN_EXTEND, MVT::v4i32, MVT::v4i8, 2 },
806     { ISD::ZERO_EXTEND, MVT::v4i32, MVT::v4i8, 2 },
807     { ISD::SIGN_EXTEND, MVT::v2i64, MVT::v2i8, 10 },
808     { ISD::ZERO_EXTEND, MVT::v2i64, MVT::v2i8, 2 },
809     { ISD::SIGN_EXTEND, MVT::v4i32, MVT::v4i16, 1 },
810     { ISD::ZERO_EXTEND, MVT::v4i32, MVT::v4i16, 1 },
811     { ISD::SIGN_EXTEND, MVT::v2i64, MVT::v2i16, 10 },
812     { ISD::ZERO_EXTEND, MVT::v2i64, MVT::v2i16, 2 },
813     { ISD::SIGN_EXTEND, MVT::v2i64, MVT::v2i32, 8 },
814     { ISD::ZERO_EXTEND, MVT::v2i64, MVT::v2i32, 2 },
815   };
816 
817   if (SrcTy.isVector() && ST->hasMVEIntegerOps()) {
818     if (const auto *Entry = ConvertCostTableLookup(MVEVectorConversionTbl,
819                                                    ISD, DstTy.getSimpleVT(),
820                                                    SrcTy.getSimpleVT()))
821       return Entry->Cost * ST->getMVEVectorCostFactor(CostKind);
822   }
823 
824   if (ISD == ISD::FP_ROUND || ISD == ISD::FP_EXTEND) {
825     // As general rule, fp converts that were not matched above are scalarized
826     // and cost 1 vcvt for each lane, so long as the instruction is available.
827     // If not it will become a series of function calls.
828     const InstructionCost CallCost =
829         getCallInstrCost(nullptr, Dst, {Src}, CostKind);
830     int Lanes = 1;
831     if (SrcTy.isFixedLengthVector())
832       Lanes = SrcTy.getVectorNumElements();
833 
834     if (IsLegalFPType(SrcTy) && IsLegalFPType(DstTy))
835       return Lanes;
836     else
837       return Lanes * CallCost;
838   }
839 
840   if (ISD == ISD::TRUNCATE && ST->hasMVEIntegerOps() &&
841       SrcTy.isFixedLengthVector()) {
842     // Treat a truncate with larger than legal source (128bits for MVE) as
843     // expensive, 2 instructions per lane.
844     if ((SrcTy.getScalarType() == MVT::i8 ||
845          SrcTy.getScalarType() == MVT::i16 ||
846          SrcTy.getScalarType() == MVT::i32) &&
847         SrcTy.getSizeInBits() > 128 &&
848         SrcTy.getSizeInBits() > DstTy.getSizeInBits())
849       return SrcTy.getVectorNumElements() * 2;
850   }
851 
852   // Scalar integer conversion costs.
853   static const TypeConversionCostTblEntry ARMIntegerConversionTbl[] = {
854     // i16 -> i64 requires two dependent operations.
855     { ISD::SIGN_EXTEND, MVT::i64, MVT::i16, 2 },
856 
857     // Truncates on i64 are assumed to be free.
858     { ISD::TRUNCATE,    MVT::i32, MVT::i64, 0 },
859     { ISD::TRUNCATE,    MVT::i16, MVT::i64, 0 },
860     { ISD::TRUNCATE,    MVT::i8,  MVT::i64, 0 },
861     { ISD::TRUNCATE,    MVT::i1,  MVT::i64, 0 }
862   };
863 
864   if (SrcTy.isInteger()) {
865     if (const auto *Entry = ConvertCostTableLookup(ARMIntegerConversionTbl, ISD,
866                                                    DstTy.getSimpleVT(),
867                                                    SrcTy.getSimpleVT()))
868       return AdjustCost(Entry->Cost);
869   }
870 
871   int BaseCost = ST->hasMVEIntegerOps() && Src->isVectorTy()
872                      ? ST->getMVEVectorCostFactor(CostKind)
873                      : 1;
874   return AdjustCost(
875       BaseCost * BaseT::getCastInstrCost(Opcode, Dst, Src, CCH, CostKind, I));
876 }
877 
getVectorInstrCost(unsigned Opcode,Type * ValTy,TTI::TargetCostKind CostKind,unsigned Index,Value * Op0,Value * Op1)878 InstructionCost ARMTTIImpl::getVectorInstrCost(unsigned Opcode, Type *ValTy,
879                                                TTI::TargetCostKind CostKind,
880                                                unsigned Index, Value *Op0,
881                                                Value *Op1) {
882   // Penalize inserting into an D-subregister. We end up with a three times
883   // lower estimated throughput on swift.
884   if (ST->hasSlowLoadDSubregister() && Opcode == Instruction::InsertElement &&
885       ValTy->isVectorTy() && ValTy->getScalarSizeInBits() <= 32)
886     return 3;
887 
888   if (ST->hasNEON() && (Opcode == Instruction::InsertElement ||
889                         Opcode == Instruction::ExtractElement)) {
890     // Cross-class copies are expensive on many microarchitectures,
891     // so assume they are expensive by default.
892     if (cast<VectorType>(ValTy)->getElementType()->isIntegerTy())
893       return 3;
894 
895     // Even if it's not a cross class copy, this likely leads to mixing
896     // of NEON and VFP code and should be therefore penalized.
897     if (ValTy->isVectorTy() &&
898         ValTy->getScalarSizeInBits() <= 32)
899       return std::max<InstructionCost>(
900           BaseT::getVectorInstrCost(Opcode, ValTy, CostKind, Index, Op0, Op1),
901           2U);
902   }
903 
904   if (ST->hasMVEIntegerOps() && (Opcode == Instruction::InsertElement ||
905                                  Opcode == Instruction::ExtractElement)) {
906     // Integer cross-lane moves are more expensive than float, which can
907     // sometimes just be vmovs. Integer involve being passes to GPR registers,
908     // causing more of a delay.
909     std::pair<InstructionCost, MVT> LT =
910         getTypeLegalizationCost(ValTy->getScalarType());
911     return LT.first * (ValTy->getScalarType()->isIntegerTy() ? 4 : 1);
912   }
913 
914   return BaseT::getVectorInstrCost(Opcode, ValTy, CostKind, Index, Op0, Op1);
915 }
916 
getCmpSelInstrCost(unsigned Opcode,Type * ValTy,Type * CondTy,CmpInst::Predicate VecPred,TTI::TargetCostKind CostKind,const Instruction * I)917 InstructionCost ARMTTIImpl::getCmpSelInstrCost(unsigned Opcode, Type *ValTy,
918                                                Type *CondTy,
919                                                CmpInst::Predicate VecPred,
920                                                TTI::TargetCostKind CostKind,
921                                                const Instruction *I) {
922   int ISD = TLI->InstructionOpcodeToISD(Opcode);
923 
924   // Thumb scalar code size cost for select.
925   if (CostKind == TTI::TCK_CodeSize && ISD == ISD::SELECT &&
926       ST->isThumb() && !ValTy->isVectorTy()) {
927     // Assume expensive structs.
928     if (TLI->getValueType(DL, ValTy, true) == MVT::Other)
929       return TTI::TCC_Expensive;
930 
931     // Select costs can vary because they:
932     // - may require one or more conditional mov (including an IT),
933     // - can't operate directly on immediates,
934     // - require live flags, which we can't copy around easily.
935     InstructionCost Cost = getTypeLegalizationCost(ValTy).first;
936 
937     // Possible IT instruction for Thumb2, or more for Thumb1.
938     ++Cost;
939 
940     // i1 values may need rematerialising by using mov immediates and/or
941     // flag setting instructions.
942     if (ValTy->isIntegerTy(1))
943       ++Cost;
944 
945     return Cost;
946   }
947 
948   // If this is a vector min/max/abs, use the cost of that intrinsic directly
949   // instead. Hopefully when min/max intrinsics are more prevalent this code
950   // will not be needed.
951   const Instruction *Sel = I;
952   if ((Opcode == Instruction::ICmp || Opcode == Instruction::FCmp) && Sel &&
953       Sel->hasOneUse())
954     Sel = cast<Instruction>(Sel->user_back());
955   if (Sel && ValTy->isVectorTy() &&
956       (ValTy->isIntOrIntVectorTy() || ValTy->isFPOrFPVectorTy())) {
957     const Value *LHS, *RHS;
958     SelectPatternFlavor SPF = matchSelectPattern(Sel, LHS, RHS).Flavor;
959     unsigned IID = 0;
960     switch (SPF) {
961     case SPF_ABS:
962       IID = Intrinsic::abs;
963       break;
964     case SPF_SMIN:
965       IID = Intrinsic::smin;
966       break;
967     case SPF_SMAX:
968       IID = Intrinsic::smax;
969       break;
970     case SPF_UMIN:
971       IID = Intrinsic::umin;
972       break;
973     case SPF_UMAX:
974       IID = Intrinsic::umax;
975       break;
976     case SPF_FMINNUM:
977       IID = Intrinsic::minnum;
978       break;
979     case SPF_FMAXNUM:
980       IID = Intrinsic::maxnum;
981       break;
982     default:
983       break;
984     }
985     if (IID) {
986       // The ICmp is free, the select gets the cost of the min/max/etc
987       if (Sel != I)
988         return 0;
989       IntrinsicCostAttributes CostAttrs(IID, ValTy, {ValTy, ValTy});
990       return getIntrinsicInstrCost(CostAttrs, CostKind);
991     }
992   }
993 
994   // On NEON a vector select gets lowered to vbsl.
995   if (ST->hasNEON() && ValTy->isVectorTy() && ISD == ISD::SELECT && CondTy) {
996     // Lowering of some vector selects is currently far from perfect.
997     static const TypeConversionCostTblEntry NEONVectorSelectTbl[] = {
998       { ISD::SELECT, MVT::v4i1, MVT::v4i64, 4*4 + 1*2 + 1 },
999       { ISD::SELECT, MVT::v8i1, MVT::v8i64, 50 },
1000       { ISD::SELECT, MVT::v16i1, MVT::v16i64, 100 }
1001     };
1002 
1003     EVT SelCondTy = TLI->getValueType(DL, CondTy);
1004     EVT SelValTy = TLI->getValueType(DL, ValTy);
1005     if (SelCondTy.isSimple() && SelValTy.isSimple()) {
1006       if (const auto *Entry = ConvertCostTableLookup(NEONVectorSelectTbl, ISD,
1007                                                      SelCondTy.getSimpleVT(),
1008                                                      SelValTy.getSimpleVT()))
1009         return Entry->Cost;
1010     }
1011 
1012     std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(ValTy);
1013     return LT.first;
1014   }
1015 
1016   if (ST->hasMVEIntegerOps() && ValTy->isVectorTy() &&
1017       (Opcode == Instruction::ICmp || Opcode == Instruction::FCmp) &&
1018       cast<FixedVectorType>(ValTy)->getNumElements() > 1) {
1019     FixedVectorType *VecValTy = cast<FixedVectorType>(ValTy);
1020     FixedVectorType *VecCondTy = dyn_cast_or_null<FixedVectorType>(CondTy);
1021     if (!VecCondTy)
1022       VecCondTy = cast<FixedVectorType>(CmpInst::makeCmpResultType(VecValTy));
1023 
1024     // If we don't have mve.fp any fp operations will need to be scalarized.
1025     if (Opcode == Instruction::FCmp && !ST->hasMVEFloatOps()) {
1026       // One scalaization insert, one scalarization extract and the cost of the
1027       // fcmps.
1028       return BaseT::getScalarizationOverhead(VecValTy, /*Insert*/ false,
1029                                              /*Extract*/ true, CostKind) +
1030              BaseT::getScalarizationOverhead(VecCondTy, /*Insert*/ true,
1031                                              /*Extract*/ false, CostKind) +
1032              VecValTy->getNumElements() *
1033                  getCmpSelInstrCost(Opcode, ValTy->getScalarType(),
1034                                     VecCondTy->getScalarType(), VecPred,
1035                                     CostKind, I);
1036     }
1037 
1038     std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(ValTy);
1039     int BaseCost = ST->getMVEVectorCostFactor(CostKind);
1040     // There are two types - the input that specifies the type of the compare
1041     // and the output vXi1 type. Because we don't know how the output will be
1042     // split, we may need an expensive shuffle to get two in sync. This has the
1043     // effect of making larger than legal compares (v8i32 for example)
1044     // expensive.
1045     if (LT.second.isVector() && LT.second.getVectorNumElements() > 2) {
1046       if (LT.first > 1)
1047         return LT.first * BaseCost +
1048                BaseT::getScalarizationOverhead(VecCondTy, /*Insert*/ true,
1049                                                /*Extract*/ false, CostKind);
1050       return BaseCost;
1051     }
1052   }
1053 
1054   // Default to cheap (throughput/size of 1 instruction) but adjust throughput
1055   // for "multiple beats" potentially needed by MVE instructions.
1056   int BaseCost = 1;
1057   if (ST->hasMVEIntegerOps() && ValTy->isVectorTy())
1058     BaseCost = ST->getMVEVectorCostFactor(CostKind);
1059 
1060   return BaseCost *
1061          BaseT::getCmpSelInstrCost(Opcode, ValTy, CondTy, VecPred, CostKind, I);
1062 }
1063 
getAddressComputationCost(Type * Ty,ScalarEvolution * SE,const SCEV * Ptr)1064 InstructionCost ARMTTIImpl::getAddressComputationCost(Type *Ty,
1065                                                       ScalarEvolution *SE,
1066                                                       const SCEV *Ptr) {
1067   // Address computations in vectorized code with non-consecutive addresses will
1068   // likely result in more instructions compared to scalar code where the
1069   // computation can more often be merged into the index mode. The resulting
1070   // extra micro-ops can significantly decrease throughput.
1071   unsigned NumVectorInstToHideOverhead = 10;
1072   int MaxMergeDistance = 64;
1073 
1074   if (ST->hasNEON()) {
1075     if (Ty->isVectorTy() && SE &&
1076         !BaseT::isConstantStridedAccessLessThan(SE, Ptr, MaxMergeDistance + 1))
1077       return NumVectorInstToHideOverhead;
1078 
1079     // In many cases the address computation is not merged into the instruction
1080     // addressing mode.
1081     return 1;
1082   }
1083   return BaseT::getAddressComputationCost(Ty, SE, Ptr);
1084 }
1085 
isProfitableLSRChainElement(Instruction * I)1086 bool ARMTTIImpl::isProfitableLSRChainElement(Instruction *I) {
1087   if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
1088     // If a VCTP is part of a chain, it's already profitable and shouldn't be
1089     // optimized, else LSR may block tail-predication.
1090     switch (II->getIntrinsicID()) {
1091     case Intrinsic::arm_mve_vctp8:
1092     case Intrinsic::arm_mve_vctp16:
1093     case Intrinsic::arm_mve_vctp32:
1094     case Intrinsic::arm_mve_vctp64:
1095       return true;
1096     default:
1097       break;
1098     }
1099   }
1100   return false;
1101 }
1102 
isLegalMaskedLoad(Type * DataTy,Align Alignment)1103 bool ARMTTIImpl::isLegalMaskedLoad(Type *DataTy, Align Alignment) {
1104   if (!EnableMaskedLoadStores || !ST->hasMVEIntegerOps())
1105     return false;
1106 
1107   if (auto *VecTy = dyn_cast<FixedVectorType>(DataTy)) {
1108     // Don't support v2i1 yet.
1109     if (VecTy->getNumElements() == 2)
1110       return false;
1111 
1112     // We don't support extending fp types.
1113      unsigned VecWidth = DataTy->getPrimitiveSizeInBits();
1114     if (VecWidth != 128 && VecTy->getElementType()->isFloatingPointTy())
1115       return false;
1116   }
1117 
1118   unsigned EltWidth = DataTy->getScalarSizeInBits();
1119   return (EltWidth == 32 && Alignment >= 4) ||
1120          (EltWidth == 16 && Alignment >= 2) || (EltWidth == 8);
1121 }
1122 
isLegalMaskedGather(Type * Ty,Align Alignment)1123 bool ARMTTIImpl::isLegalMaskedGather(Type *Ty, Align Alignment) {
1124   if (!EnableMaskedGatherScatters || !ST->hasMVEIntegerOps())
1125     return false;
1126 
1127   unsigned EltWidth = Ty->getScalarSizeInBits();
1128   return ((EltWidth == 32 && Alignment >= 4) ||
1129           (EltWidth == 16 && Alignment >= 2) || EltWidth == 8);
1130 }
1131 
1132 /// Given a memcpy/memset/memmove instruction, return the number of memory
1133 /// operations performed, via querying findOptimalMemOpLowering. Returns -1 if a
1134 /// call is used.
getNumMemOps(const IntrinsicInst * I) const1135 int ARMTTIImpl::getNumMemOps(const IntrinsicInst *I) const {
1136   MemOp MOp;
1137   unsigned DstAddrSpace = ~0u;
1138   unsigned SrcAddrSpace = ~0u;
1139   const Function *F = I->getParent()->getParent();
1140 
1141   if (const auto *MC = dyn_cast<MemTransferInst>(I)) {
1142     ConstantInt *C = dyn_cast<ConstantInt>(MC->getLength());
1143     // If 'size' is not a constant, a library call will be generated.
1144     if (!C)
1145       return -1;
1146 
1147     const unsigned Size = C->getValue().getZExtValue();
1148     const Align DstAlign = *MC->getDestAlign();
1149     const Align SrcAlign = *MC->getSourceAlign();
1150 
1151     MOp = MemOp::Copy(Size, /*DstAlignCanChange*/ false, DstAlign, SrcAlign,
1152                       /*IsVolatile*/ false);
1153     DstAddrSpace = MC->getDestAddressSpace();
1154     SrcAddrSpace = MC->getSourceAddressSpace();
1155   }
1156   else if (const auto *MS = dyn_cast<MemSetInst>(I)) {
1157     ConstantInt *C = dyn_cast<ConstantInt>(MS->getLength());
1158     // If 'size' is not a constant, a library call will be generated.
1159     if (!C)
1160       return -1;
1161 
1162     const unsigned Size = C->getValue().getZExtValue();
1163     const Align DstAlign = *MS->getDestAlign();
1164 
1165     MOp = MemOp::Set(Size, /*DstAlignCanChange*/ false, DstAlign,
1166                      /*IsZeroMemset*/ false, /*IsVolatile*/ false);
1167     DstAddrSpace = MS->getDestAddressSpace();
1168   }
1169   else
1170     llvm_unreachable("Expected a memcpy/move or memset!");
1171 
1172   unsigned Limit, Factor = 2;
1173   switch(I->getIntrinsicID()) {
1174     case Intrinsic::memcpy:
1175       Limit = TLI->getMaxStoresPerMemcpy(F->hasMinSize());
1176       break;
1177     case Intrinsic::memmove:
1178       Limit = TLI->getMaxStoresPerMemmove(F->hasMinSize());
1179       break;
1180     case Intrinsic::memset:
1181       Limit = TLI->getMaxStoresPerMemset(F->hasMinSize());
1182       Factor = 1;
1183       break;
1184     default:
1185       llvm_unreachable("Expected a memcpy/move or memset!");
1186   }
1187 
1188   // MemOps will be poplulated with a list of data types that needs to be
1189   // loaded and stored. That's why we multiply the number of elements by 2 to
1190   // get the cost for this memcpy.
1191   std::vector<EVT> MemOps;
1192   if (getTLI()->findOptimalMemOpLowering(
1193           MemOps, Limit, MOp, DstAddrSpace,
1194           SrcAddrSpace, F->getAttributes()))
1195     return MemOps.size() * Factor;
1196 
1197   // If we can't find an optimal memop lowering, return the default cost
1198   return -1;
1199 }
1200 
getMemcpyCost(const Instruction * I)1201 InstructionCost ARMTTIImpl::getMemcpyCost(const Instruction *I) {
1202   int NumOps = getNumMemOps(cast<IntrinsicInst>(I));
1203 
1204   // To model the cost of a library call, we assume 1 for the call, and
1205   // 3 for the argument setup.
1206   if (NumOps == -1)
1207     return 4;
1208   return NumOps;
1209 }
1210 
getShuffleCost(TTI::ShuffleKind Kind,VectorType * Tp,ArrayRef<int> Mask,TTI::TargetCostKind CostKind,int Index,VectorType * SubTp,ArrayRef<const Value * > Args)1211 InstructionCost ARMTTIImpl::getShuffleCost(TTI::ShuffleKind Kind,
1212                                            VectorType *Tp, ArrayRef<int> Mask,
1213                                            TTI::TargetCostKind CostKind,
1214                                            int Index, VectorType *SubTp,
1215                                            ArrayRef<const Value *> Args) {
1216   Kind = improveShuffleKindFromMask(Kind, Mask, Tp, Index, SubTp);
1217   if (ST->hasNEON()) {
1218     if (Kind == TTI::SK_Broadcast) {
1219       static const CostTblEntry NEONDupTbl[] = {
1220           // VDUP handles these cases.
1221           {ISD::VECTOR_SHUFFLE, MVT::v2i32, 1},
1222           {ISD::VECTOR_SHUFFLE, MVT::v2f32, 1},
1223           {ISD::VECTOR_SHUFFLE, MVT::v2i64, 1},
1224           {ISD::VECTOR_SHUFFLE, MVT::v2f64, 1},
1225           {ISD::VECTOR_SHUFFLE, MVT::v4i16, 1},
1226           {ISD::VECTOR_SHUFFLE, MVT::v8i8, 1},
1227 
1228           {ISD::VECTOR_SHUFFLE, MVT::v4i32, 1},
1229           {ISD::VECTOR_SHUFFLE, MVT::v4f32, 1},
1230           {ISD::VECTOR_SHUFFLE, MVT::v8i16, 1},
1231           {ISD::VECTOR_SHUFFLE, MVT::v16i8, 1}};
1232 
1233       std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(Tp);
1234       if (const auto *Entry =
1235               CostTableLookup(NEONDupTbl, ISD::VECTOR_SHUFFLE, LT.second))
1236         return LT.first * Entry->Cost;
1237     }
1238     if (Kind == TTI::SK_Reverse) {
1239       static const CostTblEntry NEONShuffleTbl[] = {
1240           // Reverse shuffle cost one instruction if we are shuffling within a
1241           // double word (vrev) or two if we shuffle a quad word (vrev, vext).
1242           {ISD::VECTOR_SHUFFLE, MVT::v2i32, 1},
1243           {ISD::VECTOR_SHUFFLE, MVT::v2f32, 1},
1244           {ISD::VECTOR_SHUFFLE, MVT::v2i64, 1},
1245           {ISD::VECTOR_SHUFFLE, MVT::v2f64, 1},
1246           {ISD::VECTOR_SHUFFLE, MVT::v4i16, 1},
1247           {ISD::VECTOR_SHUFFLE, MVT::v8i8, 1},
1248 
1249           {ISD::VECTOR_SHUFFLE, MVT::v4i32, 2},
1250           {ISD::VECTOR_SHUFFLE, MVT::v4f32, 2},
1251           {ISD::VECTOR_SHUFFLE, MVT::v8i16, 2},
1252           {ISD::VECTOR_SHUFFLE, MVT::v16i8, 2}};
1253 
1254       std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(Tp);
1255       if (const auto *Entry =
1256               CostTableLookup(NEONShuffleTbl, ISD::VECTOR_SHUFFLE, LT.second))
1257         return LT.first * Entry->Cost;
1258     }
1259     if (Kind == TTI::SK_Select) {
1260       static const CostTblEntry NEONSelShuffleTbl[] = {
1261           // Select shuffle cost table for ARM. Cost is the number of
1262           // instructions
1263           // required to create the shuffled vector.
1264 
1265           {ISD::VECTOR_SHUFFLE, MVT::v2f32, 1},
1266           {ISD::VECTOR_SHUFFLE, MVT::v2i64, 1},
1267           {ISD::VECTOR_SHUFFLE, MVT::v2f64, 1},
1268           {ISD::VECTOR_SHUFFLE, MVT::v2i32, 1},
1269 
1270           {ISD::VECTOR_SHUFFLE, MVT::v4i32, 2},
1271           {ISD::VECTOR_SHUFFLE, MVT::v4f32, 2},
1272           {ISD::VECTOR_SHUFFLE, MVT::v4i16, 2},
1273 
1274           {ISD::VECTOR_SHUFFLE, MVT::v8i16, 16},
1275 
1276           {ISD::VECTOR_SHUFFLE, MVT::v16i8, 32}};
1277 
1278       std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(Tp);
1279       if (const auto *Entry = CostTableLookup(NEONSelShuffleTbl,
1280                                               ISD::VECTOR_SHUFFLE, LT.second))
1281         return LT.first * Entry->Cost;
1282     }
1283   }
1284   if (ST->hasMVEIntegerOps()) {
1285     if (Kind == TTI::SK_Broadcast) {
1286       static const CostTblEntry MVEDupTbl[] = {
1287           // VDUP handles these cases.
1288           {ISD::VECTOR_SHUFFLE, MVT::v4i32, 1},
1289           {ISD::VECTOR_SHUFFLE, MVT::v8i16, 1},
1290           {ISD::VECTOR_SHUFFLE, MVT::v16i8, 1},
1291           {ISD::VECTOR_SHUFFLE, MVT::v4f32, 1},
1292           {ISD::VECTOR_SHUFFLE, MVT::v8f16, 1}};
1293 
1294       std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(Tp);
1295       if (const auto *Entry = CostTableLookup(MVEDupTbl, ISD::VECTOR_SHUFFLE,
1296                                               LT.second))
1297         return LT.first * Entry->Cost *
1298                ST->getMVEVectorCostFactor(TTI::TCK_RecipThroughput);
1299     }
1300 
1301     if (!Mask.empty()) {
1302       std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(Tp);
1303       if (LT.second.isVector() &&
1304           Mask.size() <= LT.second.getVectorNumElements() &&
1305           (isVREVMask(Mask, LT.second, 16) || isVREVMask(Mask, LT.second, 32) ||
1306            isVREVMask(Mask, LT.second, 64)))
1307         return ST->getMVEVectorCostFactor(TTI::TCK_RecipThroughput) * LT.first;
1308     }
1309   }
1310 
1311   int BaseCost = ST->hasMVEIntegerOps() && Tp->isVectorTy()
1312                      ? ST->getMVEVectorCostFactor(TTI::TCK_RecipThroughput)
1313                      : 1;
1314   return BaseCost *
1315          BaseT::getShuffleCost(Kind, Tp, Mask, CostKind, Index, SubTp);
1316 }
1317 
getArithmeticInstrCost(unsigned Opcode,Type * Ty,TTI::TargetCostKind CostKind,TTI::OperandValueInfo Op1Info,TTI::OperandValueInfo Op2Info,ArrayRef<const Value * > Args,const Instruction * CxtI)1318 InstructionCost ARMTTIImpl::getArithmeticInstrCost(
1319     unsigned Opcode, Type *Ty, TTI::TargetCostKind CostKind,
1320     TTI::OperandValueInfo Op1Info, TTI::OperandValueInfo Op2Info,
1321     ArrayRef<const Value *> Args,
1322     const Instruction *CxtI) {
1323   int ISDOpcode = TLI->InstructionOpcodeToISD(Opcode);
1324   if (ST->isThumb() && CostKind == TTI::TCK_CodeSize && Ty->isIntegerTy(1)) {
1325     // Make operations on i1 relatively expensive as this often involves
1326     // combining predicates. AND and XOR should be easier to handle with IT
1327     // blocks.
1328     switch (ISDOpcode) {
1329     default:
1330       break;
1331     case ISD::AND:
1332     case ISD::XOR:
1333       return 2;
1334     case ISD::OR:
1335       return 3;
1336     }
1337   }
1338 
1339   std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(Ty);
1340 
1341   if (ST->hasNEON()) {
1342     const unsigned FunctionCallDivCost = 20;
1343     const unsigned ReciprocalDivCost = 10;
1344     static const CostTblEntry CostTbl[] = {
1345       // Division.
1346       // These costs are somewhat random. Choose a cost of 20 to indicate that
1347       // vectorizing devision (added function call) is going to be very expensive.
1348       // Double registers types.
1349       { ISD::SDIV, MVT::v1i64, 1 * FunctionCallDivCost},
1350       { ISD::UDIV, MVT::v1i64, 1 * FunctionCallDivCost},
1351       { ISD::SREM, MVT::v1i64, 1 * FunctionCallDivCost},
1352       { ISD::UREM, MVT::v1i64, 1 * FunctionCallDivCost},
1353       { ISD::SDIV, MVT::v2i32, 2 * FunctionCallDivCost},
1354       { ISD::UDIV, MVT::v2i32, 2 * FunctionCallDivCost},
1355       { ISD::SREM, MVT::v2i32, 2 * FunctionCallDivCost},
1356       { ISD::UREM, MVT::v2i32, 2 * FunctionCallDivCost},
1357       { ISD::SDIV, MVT::v4i16,     ReciprocalDivCost},
1358       { ISD::UDIV, MVT::v4i16,     ReciprocalDivCost},
1359       { ISD::SREM, MVT::v4i16, 4 * FunctionCallDivCost},
1360       { ISD::UREM, MVT::v4i16, 4 * FunctionCallDivCost},
1361       { ISD::SDIV, MVT::v8i8,      ReciprocalDivCost},
1362       { ISD::UDIV, MVT::v8i8,      ReciprocalDivCost},
1363       { ISD::SREM, MVT::v8i8,  8 * FunctionCallDivCost},
1364       { ISD::UREM, MVT::v8i8,  8 * FunctionCallDivCost},
1365       // Quad register types.
1366       { ISD::SDIV, MVT::v2i64, 2 * FunctionCallDivCost},
1367       { ISD::UDIV, MVT::v2i64, 2 * FunctionCallDivCost},
1368       { ISD::SREM, MVT::v2i64, 2 * FunctionCallDivCost},
1369       { ISD::UREM, MVT::v2i64, 2 * FunctionCallDivCost},
1370       { ISD::SDIV, MVT::v4i32, 4 * FunctionCallDivCost},
1371       { ISD::UDIV, MVT::v4i32, 4 * FunctionCallDivCost},
1372       { ISD::SREM, MVT::v4i32, 4 * FunctionCallDivCost},
1373       { ISD::UREM, MVT::v4i32, 4 * FunctionCallDivCost},
1374       { ISD::SDIV, MVT::v8i16, 8 * FunctionCallDivCost},
1375       { ISD::UDIV, MVT::v8i16, 8 * FunctionCallDivCost},
1376       { ISD::SREM, MVT::v8i16, 8 * FunctionCallDivCost},
1377       { ISD::UREM, MVT::v8i16, 8 * FunctionCallDivCost},
1378       { ISD::SDIV, MVT::v16i8, 16 * FunctionCallDivCost},
1379       { ISD::UDIV, MVT::v16i8, 16 * FunctionCallDivCost},
1380       { ISD::SREM, MVT::v16i8, 16 * FunctionCallDivCost},
1381       { ISD::UREM, MVT::v16i8, 16 * FunctionCallDivCost},
1382       // Multiplication.
1383     };
1384 
1385     if (const auto *Entry = CostTableLookup(CostTbl, ISDOpcode, LT.second))
1386       return LT.first * Entry->Cost;
1387 
1388     InstructionCost Cost = BaseT::getArithmeticInstrCost(
1389         Opcode, Ty, CostKind, Op1Info, Op2Info);
1390 
1391     // This is somewhat of a hack. The problem that we are facing is that SROA
1392     // creates a sequence of shift, and, or instructions to construct values.
1393     // These sequences are recognized by the ISel and have zero-cost. Not so for
1394     // the vectorized code. Because we have support for v2i64 but not i64 those
1395     // sequences look particularly beneficial to vectorize.
1396     // To work around this we increase the cost of v2i64 operations to make them
1397     // seem less beneficial.
1398     if (LT.second == MVT::v2i64 && Op2Info.isUniform() && Op2Info.isConstant())
1399       Cost += 4;
1400 
1401     return Cost;
1402   }
1403 
1404   // If this operation is a shift on arm/thumb2, it might well be folded into
1405   // the following instruction, hence having a cost of 0.
1406   auto LooksLikeAFreeShift = [&]() {
1407     if (ST->isThumb1Only() || Ty->isVectorTy())
1408       return false;
1409 
1410     if (!CxtI || !CxtI->hasOneUse() || !CxtI->isShift())
1411       return false;
1412     if (!Op2Info.isUniform() || !Op2Info.isConstant())
1413       return false;
1414 
1415     // Folded into a ADC/ADD/AND/BIC/CMP/EOR/MVN/ORR/ORN/RSB/SBC/SUB
1416     switch (cast<Instruction>(CxtI->user_back())->getOpcode()) {
1417     case Instruction::Add:
1418     case Instruction::Sub:
1419     case Instruction::And:
1420     case Instruction::Xor:
1421     case Instruction::Or:
1422     case Instruction::ICmp:
1423       return true;
1424     default:
1425       return false;
1426     }
1427   };
1428   if (LooksLikeAFreeShift())
1429     return 0;
1430 
1431   // Default to cheap (throughput/size of 1 instruction) but adjust throughput
1432   // for "multiple beats" potentially needed by MVE instructions.
1433   int BaseCost = 1;
1434   if (ST->hasMVEIntegerOps() && Ty->isVectorTy())
1435     BaseCost = ST->getMVEVectorCostFactor(CostKind);
1436 
1437   // The rest of this mostly follows what is done in BaseT::getArithmeticInstrCost,
1438   // without treating floats as more expensive that scalars or increasing the
1439   // costs for custom operations. The results is also multiplied by the
1440   // MVEVectorCostFactor where appropriate.
1441   if (TLI->isOperationLegalOrCustomOrPromote(ISDOpcode, LT.second))
1442     return LT.first * BaseCost;
1443 
1444   // Else this is expand, assume that we need to scalarize this op.
1445   if (auto *VTy = dyn_cast<FixedVectorType>(Ty)) {
1446     unsigned Num = VTy->getNumElements();
1447     InstructionCost Cost =
1448         getArithmeticInstrCost(Opcode, Ty->getScalarType(), CostKind);
1449     // Return the cost of multiple scalar invocation plus the cost of
1450     // inserting and extracting the values.
1451     SmallVector<Type *> Tys(Args.size(), Ty);
1452     return BaseT::getScalarizationOverhead(VTy, Args, Tys, CostKind) +
1453            Num * Cost;
1454   }
1455 
1456   return BaseCost;
1457 }
1458 
getMemoryOpCost(unsigned Opcode,Type * Src,MaybeAlign Alignment,unsigned AddressSpace,TTI::TargetCostKind CostKind,TTI::OperandValueInfo OpInfo,const Instruction * I)1459 InstructionCost ARMTTIImpl::getMemoryOpCost(unsigned Opcode, Type *Src,
1460                                             MaybeAlign Alignment,
1461                                             unsigned AddressSpace,
1462                                             TTI::TargetCostKind CostKind,
1463                                             TTI::OperandValueInfo OpInfo,
1464                                             const Instruction *I) {
1465   // TODO: Handle other cost kinds.
1466   if (CostKind != TTI::TCK_RecipThroughput)
1467     return 1;
1468 
1469   // Type legalization can't handle structs
1470   if (TLI->getValueType(DL, Src, true) == MVT::Other)
1471     return BaseT::getMemoryOpCost(Opcode, Src, Alignment, AddressSpace,
1472                                   CostKind);
1473 
1474   if (ST->hasNEON() && Src->isVectorTy() &&
1475       (Alignment && *Alignment != Align(16)) &&
1476       cast<VectorType>(Src)->getElementType()->isDoubleTy()) {
1477     // Unaligned loads/stores are extremely inefficient.
1478     // We need 4 uops for vst.1/vld.1 vs 1uop for vldr/vstr.
1479     std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(Src);
1480     return LT.first * 4;
1481   }
1482 
1483   // MVE can optimize a fpext(load(4xhalf)) using an extending integer load.
1484   // Same for stores.
1485   if (ST->hasMVEFloatOps() && isa<FixedVectorType>(Src) && I &&
1486       ((Opcode == Instruction::Load && I->hasOneUse() &&
1487         isa<FPExtInst>(*I->user_begin())) ||
1488        (Opcode == Instruction::Store && isa<FPTruncInst>(I->getOperand(0))))) {
1489     FixedVectorType *SrcVTy = cast<FixedVectorType>(Src);
1490     Type *DstTy =
1491         Opcode == Instruction::Load
1492             ? (*I->user_begin())->getType()
1493             : cast<Instruction>(I->getOperand(0))->getOperand(0)->getType();
1494     if (SrcVTy->getNumElements() == 4 && SrcVTy->getScalarType()->isHalfTy() &&
1495         DstTy->getScalarType()->isFloatTy())
1496       return ST->getMVEVectorCostFactor(CostKind);
1497   }
1498 
1499   int BaseCost = ST->hasMVEIntegerOps() && Src->isVectorTy()
1500                      ? ST->getMVEVectorCostFactor(CostKind)
1501                      : 1;
1502   return BaseCost * BaseT::getMemoryOpCost(Opcode, Src, Alignment, AddressSpace,
1503                                            CostKind, OpInfo, I);
1504 }
1505 
1506 InstructionCost
getMaskedMemoryOpCost(unsigned Opcode,Type * Src,Align Alignment,unsigned AddressSpace,TTI::TargetCostKind CostKind)1507 ARMTTIImpl::getMaskedMemoryOpCost(unsigned Opcode, Type *Src, Align Alignment,
1508                                   unsigned AddressSpace,
1509                                   TTI::TargetCostKind CostKind) {
1510   if (ST->hasMVEIntegerOps()) {
1511     if (Opcode == Instruction::Load && isLegalMaskedLoad(Src, Alignment))
1512       return ST->getMVEVectorCostFactor(CostKind);
1513     if (Opcode == Instruction::Store && isLegalMaskedStore(Src, Alignment))
1514       return ST->getMVEVectorCostFactor(CostKind);
1515   }
1516   if (!isa<FixedVectorType>(Src))
1517     return BaseT::getMaskedMemoryOpCost(Opcode, Src, Alignment, AddressSpace,
1518                                         CostKind);
1519   // Scalar cost, which is currently very high due to the efficiency of the
1520   // generated code.
1521   return cast<FixedVectorType>(Src)->getNumElements() * 8;
1522 }
1523 
getInterleavedMemoryOpCost(unsigned Opcode,Type * VecTy,unsigned Factor,ArrayRef<unsigned> Indices,Align Alignment,unsigned AddressSpace,TTI::TargetCostKind CostKind,bool UseMaskForCond,bool UseMaskForGaps)1524 InstructionCost ARMTTIImpl::getInterleavedMemoryOpCost(
1525     unsigned Opcode, Type *VecTy, unsigned Factor, ArrayRef<unsigned> Indices,
1526     Align Alignment, unsigned AddressSpace, TTI::TargetCostKind CostKind,
1527     bool UseMaskForCond, bool UseMaskForGaps) {
1528   assert(Factor >= 2 && "Invalid interleave factor");
1529   assert(isa<VectorType>(VecTy) && "Expect a vector type");
1530 
1531   // vldN/vstN doesn't support vector types of i64/f64 element.
1532   bool EltIs64Bits = DL.getTypeSizeInBits(VecTy->getScalarType()) == 64;
1533 
1534   if (Factor <= TLI->getMaxSupportedInterleaveFactor() && !EltIs64Bits &&
1535       !UseMaskForCond && !UseMaskForGaps) {
1536     unsigned NumElts = cast<FixedVectorType>(VecTy)->getNumElements();
1537     auto *SubVecTy =
1538         FixedVectorType::get(VecTy->getScalarType(), NumElts / Factor);
1539 
1540     // vldN/vstN only support legal vector types of size 64 or 128 in bits.
1541     // Accesses having vector types that are a multiple of 128 bits can be
1542     // matched to more than one vldN/vstN instruction.
1543     int BaseCost =
1544         ST->hasMVEIntegerOps() ? ST->getMVEVectorCostFactor(CostKind) : 1;
1545     if (NumElts % Factor == 0 &&
1546         TLI->isLegalInterleavedAccessType(Factor, SubVecTy, Alignment, DL))
1547       return Factor * BaseCost * TLI->getNumInterleavedAccesses(SubVecTy, DL);
1548 
1549     // Some smaller than legal interleaved patterns are cheap as we can make
1550     // use of the vmovn or vrev patterns to interleave a standard load. This is
1551     // true for v4i8, v8i8 and v4i16 at least (but not for v4f16 as it is
1552     // promoted differently). The cost of 2 here is then a load and vrev or
1553     // vmovn.
1554     if (ST->hasMVEIntegerOps() && Factor == 2 && NumElts / Factor > 2 &&
1555         VecTy->isIntOrIntVectorTy() &&
1556         DL.getTypeSizeInBits(SubVecTy).getFixedValue() <= 64)
1557       return 2 * BaseCost;
1558   }
1559 
1560   return BaseT::getInterleavedMemoryOpCost(Opcode, VecTy, Factor, Indices,
1561                                            Alignment, AddressSpace, CostKind,
1562                                            UseMaskForCond, UseMaskForGaps);
1563 }
1564 
getGatherScatterOpCost(unsigned Opcode,Type * DataTy,const Value * Ptr,bool VariableMask,Align Alignment,TTI::TargetCostKind CostKind,const Instruction * I)1565 InstructionCost ARMTTIImpl::getGatherScatterOpCost(
1566     unsigned Opcode, Type *DataTy, const Value *Ptr, bool VariableMask,
1567     Align Alignment, TTI::TargetCostKind CostKind, const Instruction *I) {
1568   using namespace PatternMatch;
1569   if (!ST->hasMVEIntegerOps() || !EnableMaskedGatherScatters)
1570     return BaseT::getGatherScatterOpCost(Opcode, DataTy, Ptr, VariableMask,
1571                                          Alignment, CostKind, I);
1572 
1573   assert(DataTy->isVectorTy() && "Can't do gather/scatters on scalar!");
1574   auto *VTy = cast<FixedVectorType>(DataTy);
1575 
1576   // TODO: Splitting, once we do that.
1577 
1578   unsigned NumElems = VTy->getNumElements();
1579   unsigned EltSize = VTy->getScalarSizeInBits();
1580   std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(DataTy);
1581 
1582   // For now, it is assumed that for the MVE gather instructions the loads are
1583   // all effectively serialised. This means the cost is the scalar cost
1584   // multiplied by the number of elements being loaded. This is possibly very
1585   // conservative, but even so we still end up vectorising loops because the
1586   // cost per iteration for many loops is lower than for scalar loops.
1587   InstructionCost VectorCost =
1588       NumElems * LT.first * ST->getMVEVectorCostFactor(CostKind);
1589   // The scalarization cost should be a lot higher. We use the number of vector
1590   // elements plus the scalarization overhead. If masking is required then a lot
1591   // of little blocks will be needed and potentially a scalarized p0 mask,
1592   // greatly increasing the cost.
1593   InstructionCost ScalarCost =
1594       NumElems * LT.first + (VariableMask ? NumElems * 5 : 0) +
1595       BaseT::getScalarizationOverhead(VTy, /*Insert*/ true, /*Extract*/ false,
1596                                       CostKind) +
1597       BaseT::getScalarizationOverhead(VTy, /*Insert*/ false, /*Extract*/ true,
1598                                       CostKind);
1599 
1600   if (EltSize < 8 || Alignment < EltSize / 8)
1601     return ScalarCost;
1602 
1603   unsigned ExtSize = EltSize;
1604   // Check whether there's a single user that asks for an extended type
1605   if (I != nullptr) {
1606     // Dependent of the caller of this function, a gather instruction will
1607     // either have opcode Instruction::Load or be a call to the masked_gather
1608     // intrinsic
1609     if ((I->getOpcode() == Instruction::Load ||
1610          match(I, m_Intrinsic<Intrinsic::masked_gather>())) &&
1611         I->hasOneUse()) {
1612       const User *Us = *I->users().begin();
1613       if (isa<ZExtInst>(Us) || isa<SExtInst>(Us)) {
1614         // only allow valid type combinations
1615         unsigned TypeSize =
1616             cast<Instruction>(Us)->getType()->getScalarSizeInBits();
1617         if (((TypeSize == 32 && (EltSize == 8 || EltSize == 16)) ||
1618              (TypeSize == 16 && EltSize == 8)) &&
1619             TypeSize * NumElems == 128) {
1620           ExtSize = TypeSize;
1621         }
1622       }
1623     }
1624     // Check whether the input data needs to be truncated
1625     TruncInst *T;
1626     if ((I->getOpcode() == Instruction::Store ||
1627          match(I, m_Intrinsic<Intrinsic::masked_scatter>())) &&
1628         (T = dyn_cast<TruncInst>(I->getOperand(0)))) {
1629       // Only allow valid type combinations
1630       unsigned TypeSize = T->getOperand(0)->getType()->getScalarSizeInBits();
1631       if (((EltSize == 16 && TypeSize == 32) ||
1632            (EltSize == 8 && (TypeSize == 32 || TypeSize == 16))) &&
1633           TypeSize * NumElems == 128)
1634         ExtSize = TypeSize;
1635     }
1636   }
1637 
1638   if (ExtSize * NumElems != 128 || NumElems < 4)
1639     return ScalarCost;
1640 
1641   // Any (aligned) i32 gather will not need to be scalarised.
1642   if (ExtSize == 32)
1643     return VectorCost;
1644   // For smaller types, we need to ensure that the gep's inputs are correctly
1645   // extended from a small enough value. Other sizes (including i64) are
1646   // scalarized for now.
1647   if (ExtSize != 8 && ExtSize != 16)
1648     return ScalarCost;
1649 
1650   if (const auto *BC = dyn_cast<BitCastInst>(Ptr))
1651     Ptr = BC->getOperand(0);
1652   if (const auto *GEP = dyn_cast<GetElementPtrInst>(Ptr)) {
1653     if (GEP->getNumOperands() != 2)
1654       return ScalarCost;
1655     unsigned Scale = DL.getTypeAllocSize(GEP->getResultElementType());
1656     // Scale needs to be correct (which is only relevant for i16s).
1657     if (Scale != 1 && Scale * 8 != ExtSize)
1658       return ScalarCost;
1659     // And we need to zext (not sext) the indexes from a small enough type.
1660     if (const auto *ZExt = dyn_cast<ZExtInst>(GEP->getOperand(1))) {
1661       if (ZExt->getOperand(0)->getType()->getScalarSizeInBits() <= ExtSize)
1662         return VectorCost;
1663     }
1664     return ScalarCost;
1665   }
1666   return ScalarCost;
1667 }
1668 
1669 InstructionCost
getArithmeticReductionCost(unsigned Opcode,VectorType * ValTy,std::optional<FastMathFlags> FMF,TTI::TargetCostKind CostKind)1670 ARMTTIImpl::getArithmeticReductionCost(unsigned Opcode, VectorType *ValTy,
1671                                        std::optional<FastMathFlags> FMF,
1672                                        TTI::TargetCostKind CostKind) {
1673 
1674   EVT ValVT = TLI->getValueType(DL, ValTy);
1675   int ISD = TLI->InstructionOpcodeToISD(Opcode);
1676   unsigned EltSize = ValVT.getScalarSizeInBits();
1677 
1678   // In general floating point reductions are a series of elementwise
1679   // operations, with free extracts on each step. These are either in-order or
1680   // treewise depending on whether that is allowed by the fast math flags.
1681   if ((ISD == ISD::FADD || ISD == ISD::FMUL) &&
1682       ((EltSize == 32 && ST->hasVFP2Base()) ||
1683        (EltSize == 64 && ST->hasFP64()) ||
1684        (EltSize == 16 && ST->hasFullFP16()))) {
1685     unsigned NumElts = cast<FixedVectorType>(ValTy)->getNumElements();
1686     unsigned VecLimit = ST->hasMVEFloatOps() ? 128 : (ST->hasNEON() ? 64 : -1);
1687     InstructionCost VecCost = 0;
1688     while (!TTI::requiresOrderedReduction(FMF) && isPowerOf2_32(NumElts) &&
1689            NumElts * EltSize > VecLimit) {
1690       Type *VecTy = FixedVectorType::get(ValTy->getElementType(), NumElts / 2);
1691       VecCost += getArithmeticInstrCost(Opcode, VecTy, CostKind);
1692       NumElts /= 2;
1693     }
1694 
1695     // For fp16 we need to extract the upper lane elements. MVE can add a
1696     // VREV+FMIN/MAX to perform another vector step instead.
1697     InstructionCost ExtractCost = 0;
1698     if (!TTI::requiresOrderedReduction(FMF) && ST->hasMVEFloatOps() &&
1699         ValVT.getVectorElementType() == MVT::f16 && NumElts == 8) {
1700       VecCost += ST->getMVEVectorCostFactor(CostKind) * 2;
1701       NumElts /= 2;
1702     } else if (ValVT.getVectorElementType() == MVT::f16)
1703       ExtractCost = NumElts / 2;
1704 
1705     return VecCost + ExtractCost +
1706            NumElts *
1707                getArithmeticInstrCost(Opcode, ValTy->getElementType(), CostKind);
1708   }
1709 
1710   if ((ISD == ISD::AND || ISD == ISD::OR || ISD == ISD::XOR) &&
1711       (EltSize == 64 || EltSize == 32 || EltSize == 16 || EltSize == 8)) {
1712     unsigned NumElts = cast<FixedVectorType>(ValTy)->getNumElements();
1713     unsigned VecLimit =
1714         ST->hasMVEIntegerOps() ? 128 : (ST->hasNEON() ? 64 : -1);
1715     InstructionCost VecCost = 0;
1716     while (isPowerOf2_32(NumElts) && NumElts * EltSize > VecLimit) {
1717       Type *VecTy = FixedVectorType::get(ValTy->getElementType(), NumElts / 2);
1718       VecCost += getArithmeticInstrCost(Opcode, VecTy, CostKind);
1719       NumElts /= 2;
1720     }
1721     // For i16/i8, MVE will perform a VREV + VORR/VAND/VEOR for the 64bit vector
1722     // step.
1723     if (ST->hasMVEIntegerOps() && ValVT.getScalarSizeInBits() <= 16 &&
1724         NumElts * EltSize == 64) {
1725       Type *VecTy = FixedVectorType::get(ValTy->getElementType(), NumElts);
1726       VecCost += ST->getMVEVectorCostFactor(CostKind) +
1727                  getArithmeticInstrCost(Opcode, VecTy, CostKind);
1728       NumElts /= 2;
1729     }
1730 
1731     // From here we extract the elements and perform the and/or/xor.
1732     InstructionCost ExtractCost = NumElts;
1733     return VecCost + ExtractCost +
1734            (NumElts - 1) * getArithmeticInstrCost(
1735                                Opcode, ValTy->getElementType(), CostKind);
1736   }
1737 
1738   if (!ST->hasMVEIntegerOps() || !ValVT.isSimple() || ISD != ISD::ADD ||
1739       TTI::requiresOrderedReduction(FMF))
1740     return BaseT::getArithmeticReductionCost(Opcode, ValTy, FMF, CostKind);
1741 
1742   std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(ValTy);
1743 
1744   static const CostTblEntry CostTblAdd[]{
1745       {ISD::ADD, MVT::v16i8, 1},
1746       {ISD::ADD, MVT::v8i16, 1},
1747       {ISD::ADD, MVT::v4i32, 1},
1748   };
1749   if (const auto *Entry = CostTableLookup(CostTblAdd, ISD, LT.second))
1750     return Entry->Cost * ST->getMVEVectorCostFactor(CostKind) * LT.first;
1751 
1752   return BaseT::getArithmeticReductionCost(Opcode, ValTy, FMF, CostKind);
1753 }
1754 
getExtendedReductionCost(unsigned Opcode,bool IsUnsigned,Type * ResTy,VectorType * ValTy,FastMathFlags FMF,TTI::TargetCostKind CostKind)1755 InstructionCost ARMTTIImpl::getExtendedReductionCost(
1756     unsigned Opcode, bool IsUnsigned, Type *ResTy, VectorType *ValTy,
1757     FastMathFlags FMF, TTI::TargetCostKind CostKind) {
1758   EVT ValVT = TLI->getValueType(DL, ValTy);
1759   EVT ResVT = TLI->getValueType(DL, ResTy);
1760 
1761   int ISD = TLI->InstructionOpcodeToISD(Opcode);
1762 
1763   switch (ISD) {
1764   case ISD::ADD:
1765     if (ST->hasMVEIntegerOps() && ValVT.isSimple() && ResVT.isSimple()) {
1766       std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(ValTy);
1767 
1768       // The legal cases are:
1769       //   VADDV u/s 8/16/32
1770       //   VADDLV u/s 32
1771       // Codegen currently cannot always handle larger than legal vectors very
1772       // well, especially for predicated reductions where the mask needs to be
1773       // split, so restrict to 128bit or smaller input types.
1774       unsigned RevVTSize = ResVT.getSizeInBits();
1775       if (ValVT.getSizeInBits() <= 128 &&
1776           ((LT.second == MVT::v16i8 && RevVTSize <= 32) ||
1777            (LT.second == MVT::v8i16 && RevVTSize <= 32) ||
1778            (LT.second == MVT::v4i32 && RevVTSize <= 64)))
1779         return ST->getMVEVectorCostFactor(CostKind) * LT.first;
1780     }
1781     break;
1782   default:
1783     break;
1784   }
1785   return BaseT::getExtendedReductionCost(Opcode, IsUnsigned, ResTy, ValTy, FMF,
1786                                          CostKind);
1787 }
1788 
1789 InstructionCost
getMulAccReductionCost(bool IsUnsigned,Type * ResTy,VectorType * ValTy,TTI::TargetCostKind CostKind)1790 ARMTTIImpl::getMulAccReductionCost(bool IsUnsigned, Type *ResTy,
1791                                    VectorType *ValTy,
1792                                    TTI::TargetCostKind CostKind) {
1793   EVT ValVT = TLI->getValueType(DL, ValTy);
1794   EVT ResVT = TLI->getValueType(DL, ResTy);
1795 
1796   if (ST->hasMVEIntegerOps() && ValVT.isSimple() && ResVT.isSimple()) {
1797     std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(ValTy);
1798 
1799     // The legal cases are:
1800     //   VMLAV u/s 8/16/32
1801     //   VMLALV u/s 16/32
1802     // Codegen currently cannot always handle larger than legal vectors very
1803     // well, especially for predicated reductions where the mask needs to be
1804     // split, so restrict to 128bit or smaller input types.
1805     unsigned RevVTSize = ResVT.getSizeInBits();
1806     if (ValVT.getSizeInBits() <= 128 &&
1807         ((LT.second == MVT::v16i8 && RevVTSize <= 32) ||
1808          (LT.second == MVT::v8i16 && RevVTSize <= 64) ||
1809          (LT.second == MVT::v4i32 && RevVTSize <= 64)))
1810       return ST->getMVEVectorCostFactor(CostKind) * LT.first;
1811   }
1812 
1813   return BaseT::getMulAccReductionCost(IsUnsigned, ResTy, ValTy, CostKind);
1814 }
1815 
1816 InstructionCost
getMinMaxReductionCost(Intrinsic::ID IID,VectorType * Ty,FastMathFlags FMF,TTI::TargetCostKind CostKind)1817 ARMTTIImpl::getMinMaxReductionCost(Intrinsic::ID IID, VectorType *Ty,
1818                                    FastMathFlags FMF,
1819                                    TTI::TargetCostKind CostKind) {
1820   EVT ValVT = TLI->getValueType(DL, Ty);
1821 
1822   // In general floating point reductions are a series of elementwise
1823   // operations, with free extracts on each step. These are either in-order or
1824   // treewise depending on whether that is allowed by the fast math flags.
1825   if ((IID == Intrinsic::minnum || IID == Intrinsic::maxnum) &&
1826       ((ValVT.getVectorElementType() == MVT::f32 && ST->hasVFP2Base()) ||
1827        (ValVT.getVectorElementType() == MVT::f64 && ST->hasFP64()) ||
1828        (ValVT.getVectorElementType() == MVT::f16 && ST->hasFullFP16()))) {
1829     unsigned NumElts = cast<FixedVectorType>(Ty)->getNumElements();
1830     unsigned EltSize = ValVT.getScalarSizeInBits();
1831     unsigned VecLimit = ST->hasMVEFloatOps() ? 128 : (ST->hasNEON() ? 64 : -1);
1832     InstructionCost VecCost;
1833     while (isPowerOf2_32(NumElts) && NumElts * EltSize > VecLimit) {
1834       Type *VecTy = FixedVectorType::get(Ty->getElementType(), NumElts/2);
1835       IntrinsicCostAttributes ICA(IID, VecTy, {VecTy, VecTy}, FMF);
1836       VecCost += getIntrinsicInstrCost(ICA, CostKind);
1837       NumElts /= 2;
1838     }
1839 
1840     // For fp16 we need to extract the upper lane elements. MVE can add a
1841     // VREV+FMIN/MAX to perform another vector step instead.
1842     InstructionCost ExtractCost = 0;
1843     if (ST->hasMVEFloatOps() && ValVT.getVectorElementType() == MVT::f16 &&
1844         NumElts == 8) {
1845       VecCost += ST->getMVEVectorCostFactor(CostKind) * 2;
1846       NumElts /= 2;
1847     } else if (ValVT.getVectorElementType() == MVT::f16)
1848       ExtractCost = cast<FixedVectorType>(Ty)->getNumElements() / 2;
1849 
1850     IntrinsicCostAttributes ICA(IID, Ty->getElementType(),
1851                                 {Ty->getElementType(), Ty->getElementType()},
1852                                 FMF);
1853     return VecCost + ExtractCost +
1854            (NumElts - 1) * getIntrinsicInstrCost(ICA, CostKind);
1855   }
1856 
1857   if (IID == Intrinsic::smin || IID == Intrinsic::smax ||
1858       IID == Intrinsic::umin || IID == Intrinsic::umax) {
1859     std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(Ty);
1860 
1861     // All costs are the same for u/s min/max.  These lower to vminv, which are
1862     // given a slightly higher cost as they tend to take multiple cycles for
1863     // smaller type sizes.
1864     static const CostTblEntry CostTblAdd[]{
1865         {ISD::SMIN, MVT::v16i8, 4},
1866         {ISD::SMIN, MVT::v8i16, 3},
1867         {ISD::SMIN, MVT::v4i32, 2},
1868     };
1869     if (const auto *Entry = CostTableLookup(CostTblAdd, ISD::SMIN, LT.second))
1870       return Entry->Cost * ST->getMVEVectorCostFactor(CostKind) * LT.first;
1871   }
1872 
1873   return BaseT::getMinMaxReductionCost(IID, Ty, FMF, CostKind);
1874 }
1875 
1876 InstructionCost
getIntrinsicInstrCost(const IntrinsicCostAttributes & ICA,TTI::TargetCostKind CostKind)1877 ARMTTIImpl::getIntrinsicInstrCost(const IntrinsicCostAttributes &ICA,
1878                                   TTI::TargetCostKind CostKind) {
1879   switch (ICA.getID()) {
1880   case Intrinsic::get_active_lane_mask:
1881     // Currently we make a somewhat optimistic assumption that
1882     // active_lane_mask's are always free. In reality it may be freely folded
1883     // into a tail predicated loop, expanded into a VCPT or expanded into a lot
1884     // of add/icmp code. We may need to improve this in the future, but being
1885     // able to detect if it is free or not involves looking at a lot of other
1886     // code. We currently assume that the vectorizer inserted these, and knew
1887     // what it was doing in adding one.
1888     if (ST->hasMVEIntegerOps())
1889       return 0;
1890     break;
1891   case Intrinsic::sadd_sat:
1892   case Intrinsic::ssub_sat:
1893   case Intrinsic::uadd_sat:
1894   case Intrinsic::usub_sat: {
1895     if (!ST->hasMVEIntegerOps())
1896       break;
1897     Type *VT = ICA.getReturnType();
1898 
1899     std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(VT);
1900     if (LT.second == MVT::v4i32 || LT.second == MVT::v8i16 ||
1901         LT.second == MVT::v16i8) {
1902       // This is a base cost of 1 for the vqadd, plus 3 extract shifts if we
1903       // need to extend the type, as it uses shr(qadd(shl, shl)).
1904       unsigned Instrs =
1905           LT.second.getScalarSizeInBits() == VT->getScalarSizeInBits() ? 1 : 4;
1906       return LT.first * ST->getMVEVectorCostFactor(CostKind) * Instrs;
1907     }
1908     break;
1909   }
1910   case Intrinsic::abs:
1911   case Intrinsic::smin:
1912   case Intrinsic::smax:
1913   case Intrinsic::umin:
1914   case Intrinsic::umax: {
1915     if (!ST->hasMVEIntegerOps())
1916       break;
1917     Type *VT = ICA.getReturnType();
1918 
1919     std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(VT);
1920     if (LT.second == MVT::v4i32 || LT.second == MVT::v8i16 ||
1921         LT.second == MVT::v16i8)
1922       return LT.first * ST->getMVEVectorCostFactor(CostKind);
1923     break;
1924   }
1925   case Intrinsic::minnum:
1926   case Intrinsic::maxnum: {
1927     if (!ST->hasMVEFloatOps())
1928       break;
1929     Type *VT = ICA.getReturnType();
1930     std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(VT);
1931     if (LT.second == MVT::v4f32 || LT.second == MVT::v8f16)
1932       return LT.first * ST->getMVEVectorCostFactor(CostKind);
1933     break;
1934   }
1935   case Intrinsic::fptosi_sat:
1936   case Intrinsic::fptoui_sat: {
1937     if (ICA.getArgTypes().empty())
1938       break;
1939     bool IsSigned = ICA.getID() == Intrinsic::fptosi_sat;
1940     auto LT = getTypeLegalizationCost(ICA.getArgTypes()[0]);
1941     EVT MTy = TLI->getValueType(DL, ICA.getReturnType());
1942     // Check for the legal types, with the corect subtarget features.
1943     if ((ST->hasVFP2Base() && LT.second == MVT::f32 && MTy == MVT::i32) ||
1944         (ST->hasFP64() && LT.second == MVT::f64 && MTy == MVT::i32) ||
1945         (ST->hasFullFP16() && LT.second == MVT::f16 && MTy == MVT::i32))
1946       return LT.first;
1947 
1948     // Equally for MVE vector types
1949     if (ST->hasMVEFloatOps() &&
1950         (LT.second == MVT::v4f32 || LT.second == MVT::v8f16) &&
1951         LT.second.getScalarSizeInBits() == MTy.getScalarSizeInBits())
1952       return LT.first * ST->getMVEVectorCostFactor(CostKind);
1953 
1954     // Otherwise we use a legal convert followed by a min+max
1955     if (((ST->hasVFP2Base() && LT.second == MVT::f32) ||
1956          (ST->hasFP64() && LT.second == MVT::f64) ||
1957          (ST->hasFullFP16() && LT.second == MVT::f16) ||
1958          (ST->hasMVEFloatOps() &&
1959           (LT.second == MVT::v4f32 || LT.second == MVT::v8f16))) &&
1960         LT.second.getScalarSizeInBits() >= MTy.getScalarSizeInBits()) {
1961       Type *LegalTy = Type::getIntNTy(ICA.getReturnType()->getContext(),
1962                                       LT.second.getScalarSizeInBits());
1963       InstructionCost Cost =
1964           LT.second.isVector() ? ST->getMVEVectorCostFactor(CostKind) : 1;
1965       IntrinsicCostAttributes Attrs1(IsSigned ? Intrinsic::smin
1966                                               : Intrinsic::umin,
1967                                      LegalTy, {LegalTy, LegalTy});
1968       Cost += getIntrinsicInstrCost(Attrs1, CostKind);
1969       IntrinsicCostAttributes Attrs2(IsSigned ? Intrinsic::smax
1970                                               : Intrinsic::umax,
1971                                      LegalTy, {LegalTy, LegalTy});
1972       Cost += getIntrinsicInstrCost(Attrs2, CostKind);
1973       return LT.first * Cost;
1974     }
1975     break;
1976   }
1977   }
1978 
1979   return BaseT::getIntrinsicInstrCost(ICA, CostKind);
1980 }
1981 
isLoweredToCall(const Function * F)1982 bool ARMTTIImpl::isLoweredToCall(const Function *F) {
1983   if (!F->isIntrinsic())
1984     return BaseT::isLoweredToCall(F);
1985 
1986   // Assume all Arm-specific intrinsics map to an instruction.
1987   if (F->getName().starts_with("llvm.arm"))
1988     return false;
1989 
1990   switch (F->getIntrinsicID()) {
1991   default: break;
1992   case Intrinsic::powi:
1993   case Intrinsic::sin:
1994   case Intrinsic::cos:
1995   case Intrinsic::pow:
1996   case Intrinsic::log:
1997   case Intrinsic::log10:
1998   case Intrinsic::log2:
1999   case Intrinsic::exp:
2000   case Intrinsic::exp2:
2001     return true;
2002   case Intrinsic::sqrt:
2003   case Intrinsic::fabs:
2004   case Intrinsic::copysign:
2005   case Intrinsic::floor:
2006   case Intrinsic::ceil:
2007   case Intrinsic::trunc:
2008   case Intrinsic::rint:
2009   case Intrinsic::nearbyint:
2010   case Intrinsic::round:
2011   case Intrinsic::canonicalize:
2012   case Intrinsic::lround:
2013   case Intrinsic::llround:
2014   case Intrinsic::lrint:
2015   case Intrinsic::llrint:
2016     if (F->getReturnType()->isDoubleTy() && !ST->hasFP64())
2017       return true;
2018     if (F->getReturnType()->isHalfTy() && !ST->hasFullFP16())
2019       return true;
2020     // Some operations can be handled by vector instructions and assume
2021     // unsupported vectors will be expanded into supported scalar ones.
2022     // TODO Handle scalar operations properly.
2023     return !ST->hasFPARMv8Base() && !ST->hasVFP2Base();
2024   case Intrinsic::masked_store:
2025   case Intrinsic::masked_load:
2026   case Intrinsic::masked_gather:
2027   case Intrinsic::masked_scatter:
2028     return !ST->hasMVEIntegerOps();
2029   case Intrinsic::sadd_with_overflow:
2030   case Intrinsic::uadd_with_overflow:
2031   case Intrinsic::ssub_with_overflow:
2032   case Intrinsic::usub_with_overflow:
2033   case Intrinsic::sadd_sat:
2034   case Intrinsic::uadd_sat:
2035   case Intrinsic::ssub_sat:
2036   case Intrinsic::usub_sat:
2037     return false;
2038   }
2039 
2040   return BaseT::isLoweredToCall(F);
2041 }
2042 
maybeLoweredToCall(Instruction & I)2043 bool ARMTTIImpl::maybeLoweredToCall(Instruction &I) {
2044   unsigned ISD = TLI->InstructionOpcodeToISD(I.getOpcode());
2045   EVT VT = TLI->getValueType(DL, I.getType(), true);
2046   if (TLI->getOperationAction(ISD, VT) == TargetLowering::LibCall)
2047     return true;
2048 
2049   // Check if an intrinsic will be lowered to a call and assume that any
2050   // other CallInst will generate a bl.
2051   if (auto *Call = dyn_cast<CallInst>(&I)) {
2052     if (auto *II = dyn_cast<IntrinsicInst>(Call)) {
2053       switch(II->getIntrinsicID()) {
2054         case Intrinsic::memcpy:
2055         case Intrinsic::memset:
2056         case Intrinsic::memmove:
2057           return getNumMemOps(II) == -1;
2058         default:
2059           if (const Function *F = Call->getCalledFunction())
2060             return isLoweredToCall(F);
2061       }
2062     }
2063     return true;
2064   }
2065 
2066   // FPv5 provides conversions between integer, double-precision,
2067   // single-precision, and half-precision formats.
2068   switch (I.getOpcode()) {
2069   default:
2070     break;
2071   case Instruction::FPToSI:
2072   case Instruction::FPToUI:
2073   case Instruction::SIToFP:
2074   case Instruction::UIToFP:
2075   case Instruction::FPTrunc:
2076   case Instruction::FPExt:
2077     return !ST->hasFPARMv8Base();
2078   }
2079 
2080   // FIXME: Unfortunately the approach of checking the Operation Action does
2081   // not catch all cases of Legalization that use library calls. Our
2082   // Legalization step categorizes some transformations into library calls as
2083   // Custom, Expand or even Legal when doing type legalization. So for now
2084   // we have to special case for instance the SDIV of 64bit integers and the
2085   // use of floating point emulation.
2086   if (VT.isInteger() && VT.getSizeInBits() >= 64) {
2087     switch (ISD) {
2088     default:
2089       break;
2090     case ISD::SDIV:
2091     case ISD::UDIV:
2092     case ISD::SREM:
2093     case ISD::UREM:
2094     case ISD::SDIVREM:
2095     case ISD::UDIVREM:
2096       return true;
2097     }
2098   }
2099 
2100   // Assume all other non-float operations are supported.
2101   if (!VT.isFloatingPoint())
2102     return false;
2103 
2104   // We'll need a library call to handle most floats when using soft.
2105   if (TLI->useSoftFloat()) {
2106     switch (I.getOpcode()) {
2107     default:
2108       return true;
2109     case Instruction::Alloca:
2110     case Instruction::Load:
2111     case Instruction::Store:
2112     case Instruction::Select:
2113     case Instruction::PHI:
2114       return false;
2115     }
2116   }
2117 
2118   // We'll need a libcall to perform double precision operations on a single
2119   // precision only FPU.
2120   if (I.getType()->isDoubleTy() && !ST->hasFP64())
2121     return true;
2122 
2123   // Likewise for half precision arithmetic.
2124   if (I.getType()->isHalfTy() && !ST->hasFullFP16())
2125     return true;
2126 
2127   return false;
2128 }
2129 
isHardwareLoopProfitable(Loop * L,ScalarEvolution & SE,AssumptionCache & AC,TargetLibraryInfo * LibInfo,HardwareLoopInfo & HWLoopInfo)2130 bool ARMTTIImpl::isHardwareLoopProfitable(Loop *L, ScalarEvolution &SE,
2131                                           AssumptionCache &AC,
2132                                           TargetLibraryInfo *LibInfo,
2133                                           HardwareLoopInfo &HWLoopInfo) {
2134   // Low-overhead branches are only supported in the 'low-overhead branch'
2135   // extension of v8.1-m.
2136   if (!ST->hasLOB() || DisableLowOverheadLoops) {
2137     LLVM_DEBUG(dbgs() << "ARMHWLoops: Disabled\n");
2138     return false;
2139   }
2140 
2141   if (!SE.hasLoopInvariantBackedgeTakenCount(L)) {
2142     LLVM_DEBUG(dbgs() << "ARMHWLoops: No BETC\n");
2143     return false;
2144   }
2145 
2146   const SCEV *BackedgeTakenCount = SE.getBackedgeTakenCount(L);
2147   if (isa<SCEVCouldNotCompute>(BackedgeTakenCount)) {
2148     LLVM_DEBUG(dbgs() << "ARMHWLoops: Uncomputable BETC\n");
2149     return false;
2150   }
2151 
2152   const SCEV *TripCountSCEV =
2153     SE.getAddExpr(BackedgeTakenCount,
2154                   SE.getOne(BackedgeTakenCount->getType()));
2155 
2156   // We need to store the trip count in LR, a 32-bit register.
2157   if (SE.getUnsignedRangeMax(TripCountSCEV).getBitWidth() > 32) {
2158     LLVM_DEBUG(dbgs() << "ARMHWLoops: Trip count does not fit into 32bits\n");
2159     return false;
2160   }
2161 
2162   // Making a call will trash LR and clear LO_BRANCH_INFO, so there's little
2163   // point in generating a hardware loop if that's going to happen.
2164 
2165   auto IsHardwareLoopIntrinsic = [](Instruction &I) {
2166     if (auto *Call = dyn_cast<IntrinsicInst>(&I)) {
2167       switch (Call->getIntrinsicID()) {
2168       default:
2169         break;
2170       case Intrinsic::start_loop_iterations:
2171       case Intrinsic::test_start_loop_iterations:
2172       case Intrinsic::loop_decrement:
2173       case Intrinsic::loop_decrement_reg:
2174         return true;
2175       }
2176     }
2177     return false;
2178   };
2179 
2180   // Scan the instructions to see if there's any that we know will turn into a
2181   // call or if this loop is already a low-overhead loop or will become a tail
2182   // predicated loop.
2183   bool IsTailPredLoop = false;
2184   auto ScanLoop = [&](Loop *L) {
2185     for (auto *BB : L->getBlocks()) {
2186       for (auto &I : *BB) {
2187         if (maybeLoweredToCall(I) || IsHardwareLoopIntrinsic(I) ||
2188             isa<InlineAsm>(I)) {
2189           LLVM_DEBUG(dbgs() << "ARMHWLoops: Bad instruction: " << I << "\n");
2190           return false;
2191         }
2192         if (auto *II = dyn_cast<IntrinsicInst>(&I))
2193           IsTailPredLoop |=
2194               II->getIntrinsicID() == Intrinsic::get_active_lane_mask ||
2195               II->getIntrinsicID() == Intrinsic::arm_mve_vctp8 ||
2196               II->getIntrinsicID() == Intrinsic::arm_mve_vctp16 ||
2197               II->getIntrinsicID() == Intrinsic::arm_mve_vctp32 ||
2198               II->getIntrinsicID() == Intrinsic::arm_mve_vctp64;
2199       }
2200     }
2201     return true;
2202   };
2203 
2204   // Visit inner loops.
2205   for (auto *Inner : *L)
2206     if (!ScanLoop(Inner))
2207       return false;
2208 
2209   if (!ScanLoop(L))
2210     return false;
2211 
2212   // TODO: Check whether the trip count calculation is expensive. If L is the
2213   // inner loop but we know it has a low trip count, calculating that trip
2214   // count (in the parent loop) may be detrimental.
2215 
2216   LLVMContext &C = L->getHeader()->getContext();
2217   HWLoopInfo.CounterInReg = true;
2218   HWLoopInfo.IsNestingLegal = false;
2219   HWLoopInfo.PerformEntryTest = AllowWLSLoops && !IsTailPredLoop;
2220   HWLoopInfo.CountType = Type::getInt32Ty(C);
2221   HWLoopInfo.LoopDecrement = ConstantInt::get(HWLoopInfo.CountType, 1);
2222   return true;
2223 }
2224 
canTailPredicateInstruction(Instruction & I,int & ICmpCount)2225 static bool canTailPredicateInstruction(Instruction &I, int &ICmpCount) {
2226   // We don't allow icmp's, and because we only look at single block loops,
2227   // we simply count the icmps, i.e. there should only be 1 for the backedge.
2228   if (isa<ICmpInst>(&I) && ++ICmpCount > 1)
2229     return false;
2230   // FIXME: This is a workaround for poor cost modelling. Min/Max intrinsics are
2231   // not currently canonical, but soon will be. Code without them uses icmp, and
2232   // so is not tail predicated as per the condition above. In order to get the
2233   // same performance we treat min and max the same as an icmp for tailpred
2234   // purposes for the moment (we often rely on non-tailpred and higher VF's to
2235   // pick more optimial instructions like VQDMULH. They need to be recognized
2236   // directly by the vectorizer).
2237   if (auto *II = dyn_cast<IntrinsicInst>(&I))
2238     if ((II->getIntrinsicID() == Intrinsic::smin ||
2239          II->getIntrinsicID() == Intrinsic::smax ||
2240          II->getIntrinsicID() == Intrinsic::umin ||
2241          II->getIntrinsicID() == Intrinsic::umax) &&
2242         ++ICmpCount > 1)
2243       return false;
2244 
2245   if (isa<FCmpInst>(&I))
2246     return false;
2247 
2248   // We could allow extending/narrowing FP loads/stores, but codegen is
2249   // too inefficient so reject this for now.
2250   if (isa<FPExtInst>(&I) || isa<FPTruncInst>(&I))
2251     return false;
2252 
2253   // Extends have to be extending-loads
2254   if (isa<SExtInst>(&I) || isa<ZExtInst>(&I) )
2255     if (!I.getOperand(0)->hasOneUse() || !isa<LoadInst>(I.getOperand(0)))
2256       return false;
2257 
2258   // Truncs have to be narrowing-stores
2259   if (isa<TruncInst>(&I) )
2260     if (!I.hasOneUse() || !isa<StoreInst>(*I.user_begin()))
2261       return false;
2262 
2263   return true;
2264 }
2265 
2266 // To set up a tail-predicated loop, we need to know the total number of
2267 // elements processed by that loop. Thus, we need to determine the element
2268 // size and:
2269 // 1) it should be uniform for all operations in the vector loop, so we
2270 //    e.g. don't want any widening/narrowing operations.
2271 // 2) it should be smaller than i64s because we don't have vector operations
2272 //    that work on i64s.
2273 // 3) we don't want elements to be reversed or shuffled, to make sure the
2274 //    tail-predication masks/predicates the right lanes.
2275 //
canTailPredicateLoop(Loop * L,LoopInfo * LI,ScalarEvolution & SE,const DataLayout & DL,const LoopAccessInfo * LAI)2276 static bool canTailPredicateLoop(Loop *L, LoopInfo *LI, ScalarEvolution &SE,
2277                                  const DataLayout &DL,
2278                                  const LoopAccessInfo *LAI) {
2279   LLVM_DEBUG(dbgs() << "Tail-predication: checking allowed instructions\n");
2280 
2281   // If there are live-out values, it is probably a reduction. We can predicate
2282   // most reduction operations freely under MVE using a combination of
2283   // prefer-predicated-reduction-select and inloop reductions. We limit this to
2284   // floating point and integer reductions, but don't check for operators
2285   // specifically here. If the value ends up not being a reduction (and so the
2286   // vectorizer cannot tailfold the loop), we should fall back to standard
2287   // vectorization automatically.
2288   SmallVector< Instruction *, 8 > LiveOuts;
2289   LiveOuts = llvm::findDefsUsedOutsideOfLoop(L);
2290   bool ReductionsDisabled =
2291       EnableTailPredication == TailPredication::EnabledNoReductions ||
2292       EnableTailPredication == TailPredication::ForceEnabledNoReductions;
2293 
2294   for (auto *I : LiveOuts) {
2295     if (!I->getType()->isIntegerTy() && !I->getType()->isFloatTy() &&
2296         !I->getType()->isHalfTy()) {
2297       LLVM_DEBUG(dbgs() << "Don't tail-predicate loop with non-integer/float "
2298                            "live-out value\n");
2299       return false;
2300     }
2301     if (ReductionsDisabled) {
2302       LLVM_DEBUG(dbgs() << "Reductions not enabled\n");
2303       return false;
2304     }
2305   }
2306 
2307   // Next, check that all instructions can be tail-predicated.
2308   PredicatedScalarEvolution PSE = LAI->getPSE();
2309   SmallVector<Instruction *, 16> LoadStores;
2310   int ICmpCount = 0;
2311 
2312   for (BasicBlock *BB : L->blocks()) {
2313     for (Instruction &I : BB->instructionsWithoutDebug()) {
2314       if (isa<PHINode>(&I))
2315         continue;
2316       if (!canTailPredicateInstruction(I, ICmpCount)) {
2317         LLVM_DEBUG(dbgs() << "Instruction not allowed: "; I.dump());
2318         return false;
2319       }
2320 
2321       Type *T  = I.getType();
2322       if (T->getScalarSizeInBits() > 32) {
2323         LLVM_DEBUG(dbgs() << "Unsupported Type: "; T->dump());
2324         return false;
2325       }
2326       if (isa<StoreInst>(I) || isa<LoadInst>(I)) {
2327         Value *Ptr = getLoadStorePointerOperand(&I);
2328         Type *AccessTy = getLoadStoreType(&I);
2329         int64_t NextStride = getPtrStride(PSE, AccessTy, Ptr, L).value_or(0);
2330         if (NextStride == 1) {
2331           // TODO: for now only allow consecutive strides of 1. We could support
2332           // other strides as long as it is uniform, but let's keep it simple
2333           // for now.
2334           continue;
2335         } else if (NextStride == -1 ||
2336                    (NextStride == 2 && MVEMaxSupportedInterleaveFactor >= 2) ||
2337                    (NextStride == 4 && MVEMaxSupportedInterleaveFactor >= 4)) {
2338           LLVM_DEBUG(dbgs()
2339                      << "Consecutive strides of 2 found, vld2/vstr2 can't "
2340                         "be tail-predicated\n.");
2341           return false;
2342           // TODO: don't tail predicate if there is a reversed load?
2343         } else if (EnableMaskedGatherScatters) {
2344           // Gather/scatters do allow loading from arbitrary strides, at
2345           // least if they are loop invariant.
2346           // TODO: Loop variant strides should in theory work, too, but
2347           // this requires further testing.
2348           const SCEV *PtrScev = PSE.getSE()->getSCEV(Ptr);
2349           if (auto AR = dyn_cast<SCEVAddRecExpr>(PtrScev)) {
2350             const SCEV *Step = AR->getStepRecurrence(*PSE.getSE());
2351             if (PSE.getSE()->isLoopInvariant(Step, L))
2352               continue;
2353           }
2354         }
2355         LLVM_DEBUG(dbgs() << "Bad stride found, can't "
2356                              "tail-predicate\n.");
2357         return false;
2358       }
2359     }
2360   }
2361 
2362   LLVM_DEBUG(dbgs() << "tail-predication: all instructions allowed!\n");
2363   return true;
2364 }
2365 
preferPredicateOverEpilogue(TailFoldingInfo * TFI)2366 bool ARMTTIImpl::preferPredicateOverEpilogue(TailFoldingInfo *TFI) {
2367   if (!EnableTailPredication) {
2368     LLVM_DEBUG(dbgs() << "Tail-predication not enabled.\n");
2369     return false;
2370   }
2371 
2372   // Creating a predicated vector loop is the first step for generating a
2373   // tail-predicated hardware loop, for which we need the MVE masked
2374   // load/stores instructions:
2375   if (!ST->hasMVEIntegerOps())
2376     return false;
2377 
2378   LoopVectorizationLegality *LVL = TFI->LVL;
2379   Loop *L = LVL->getLoop();
2380 
2381   // For now, restrict this to single block loops.
2382   if (L->getNumBlocks() > 1) {
2383     LLVM_DEBUG(dbgs() << "preferPredicateOverEpilogue: not a single block "
2384                          "loop.\n");
2385     return false;
2386   }
2387 
2388   assert(L->isInnermost() && "preferPredicateOverEpilogue: inner-loop expected");
2389 
2390   LoopInfo *LI = LVL->getLoopInfo();
2391   HardwareLoopInfo HWLoopInfo(L);
2392   if (!HWLoopInfo.canAnalyze(*LI)) {
2393     LLVM_DEBUG(dbgs() << "preferPredicateOverEpilogue: hardware-loop is not "
2394                          "analyzable.\n");
2395     return false;
2396   }
2397 
2398   AssumptionCache *AC = LVL->getAssumptionCache();
2399   ScalarEvolution *SE = LVL->getScalarEvolution();
2400 
2401   // This checks if we have the low-overhead branch architecture
2402   // extension, and if we will create a hardware-loop:
2403   if (!isHardwareLoopProfitable(L, *SE, *AC, TFI->TLI, HWLoopInfo)) {
2404     LLVM_DEBUG(dbgs() << "preferPredicateOverEpilogue: hardware-loop is not "
2405                          "profitable.\n");
2406     return false;
2407   }
2408 
2409   DominatorTree *DT = LVL->getDominatorTree();
2410   if (!HWLoopInfo.isHardwareLoopCandidate(*SE, *LI, *DT)) {
2411     LLVM_DEBUG(dbgs() << "preferPredicateOverEpilogue: hardware-loop is not "
2412                          "a candidate.\n");
2413     return false;
2414   }
2415 
2416   return canTailPredicateLoop(L, LI, *SE, DL, LVL->getLAI());
2417 }
2418 
2419 TailFoldingStyle
getPreferredTailFoldingStyle(bool IVUpdateMayOverflow) const2420 ARMTTIImpl::getPreferredTailFoldingStyle(bool IVUpdateMayOverflow) const {
2421   if (!ST->hasMVEIntegerOps() || !EnableTailPredication)
2422     return TailFoldingStyle::DataWithoutLaneMask;
2423 
2424   // Intrinsic @llvm.get.active.lane.mask is supported.
2425   // It is used in the MVETailPredication pass, which requires the number of
2426   // elements processed by this vector loop to setup the tail-predicated
2427   // loop.
2428   return TailFoldingStyle::Data;
2429 }
getUnrollingPreferences(Loop * L,ScalarEvolution & SE,TTI::UnrollingPreferences & UP,OptimizationRemarkEmitter * ORE)2430 void ARMTTIImpl::getUnrollingPreferences(Loop *L, ScalarEvolution &SE,
2431                                          TTI::UnrollingPreferences &UP,
2432                                          OptimizationRemarkEmitter *ORE) {
2433   // Enable Upper bound unrolling universally, providing that we do not see an
2434   // active lane mask, which will be better kept as a loop to become tail
2435   // predicated than to be conditionally unrolled.
2436   UP.UpperBound =
2437       !ST->hasMVEIntegerOps() || !any_of(*L->getHeader(), [](Instruction &I) {
2438         return isa<IntrinsicInst>(I) &&
2439                cast<IntrinsicInst>(I).getIntrinsicID() ==
2440                    Intrinsic::get_active_lane_mask;
2441       });
2442 
2443   // Only currently enable these preferences for M-Class cores.
2444   if (!ST->isMClass())
2445     return BasicTTIImplBase::getUnrollingPreferences(L, SE, UP, ORE);
2446 
2447   // Disable loop unrolling for Oz and Os.
2448   UP.OptSizeThreshold = 0;
2449   UP.PartialOptSizeThreshold = 0;
2450   if (L->getHeader()->getParent()->hasOptSize())
2451     return;
2452 
2453   SmallVector<BasicBlock*, 4> ExitingBlocks;
2454   L->getExitingBlocks(ExitingBlocks);
2455   LLVM_DEBUG(dbgs() << "Loop has:\n"
2456                     << "Blocks: " << L->getNumBlocks() << "\n"
2457                     << "Exit blocks: " << ExitingBlocks.size() << "\n");
2458 
2459   // Only allow another exit other than the latch. This acts as an early exit
2460   // as it mirrors the profitability calculation of the runtime unroller.
2461   if (ExitingBlocks.size() > 2)
2462     return;
2463 
2464   // Limit the CFG of the loop body for targets with a branch predictor.
2465   // Allowing 4 blocks permits if-then-else diamonds in the body.
2466   if (ST->hasBranchPredictor() && L->getNumBlocks() > 4)
2467     return;
2468 
2469   // Don't unroll vectorized loops, including the remainder loop
2470   if (getBooleanLoopAttribute(L, "llvm.loop.isvectorized"))
2471     return;
2472 
2473   // Scan the loop: don't unroll loops with calls as this could prevent
2474   // inlining.
2475   InstructionCost Cost = 0;
2476   for (auto *BB : L->getBlocks()) {
2477     for (auto &I : *BB) {
2478       // Don't unroll vectorised loop. MVE does not benefit from it as much as
2479       // scalar code.
2480       if (I.getType()->isVectorTy())
2481         return;
2482 
2483       if (isa<CallInst>(I) || isa<InvokeInst>(I)) {
2484         if (const Function *F = cast<CallBase>(I).getCalledFunction()) {
2485           if (!isLoweredToCall(F))
2486             continue;
2487         }
2488         return;
2489       }
2490 
2491       SmallVector<const Value*, 4> Operands(I.operand_values());
2492       Cost += getInstructionCost(&I, Operands,
2493                                  TargetTransformInfo::TCK_SizeAndLatency);
2494     }
2495   }
2496 
2497   // On v6m cores, there are very few registers available. We can easily end up
2498   // spilling and reloading more registers in an unrolled loop. Look at the
2499   // number of LCSSA phis as a rough measure of how many registers will need to
2500   // be live out of the loop, reducing the default unroll count if more than 1
2501   // value is needed.  In the long run, all of this should be being learnt by a
2502   // machine.
2503   unsigned UnrollCount = 4;
2504   if (ST->isThumb1Only()) {
2505     unsigned ExitingValues = 0;
2506     SmallVector<BasicBlock *, 4> ExitBlocks;
2507     L->getExitBlocks(ExitBlocks);
2508     for (auto *Exit : ExitBlocks) {
2509       // Count the number of LCSSA phis. Exclude values coming from GEP's as
2510       // only the last is expected to be needed for address operands.
2511       unsigned LiveOuts = count_if(Exit->phis(), [](auto &PH) {
2512         return PH.getNumOperands() != 1 ||
2513                !isa<GetElementPtrInst>(PH.getOperand(0));
2514       });
2515       ExitingValues = ExitingValues < LiveOuts ? LiveOuts : ExitingValues;
2516     }
2517     if (ExitingValues)
2518       UnrollCount /= ExitingValues;
2519     if (UnrollCount <= 1)
2520       return;
2521   }
2522 
2523   LLVM_DEBUG(dbgs() << "Cost of loop: " << Cost << "\n");
2524   LLVM_DEBUG(dbgs() << "Default Runtime Unroll Count: " << UnrollCount << "\n");
2525 
2526   UP.Partial = true;
2527   UP.Runtime = true;
2528   UP.UnrollRemainder = true;
2529   UP.DefaultUnrollRuntimeCount = UnrollCount;
2530   UP.UnrollAndJam = true;
2531   UP.UnrollAndJamInnerLoopThreshold = 60;
2532 
2533   // Force unrolling small loops can be very useful because of the branch
2534   // taken cost of the backedge.
2535   if (Cost < 12)
2536     UP.Force = true;
2537 }
2538 
getPeelingPreferences(Loop * L,ScalarEvolution & SE,TTI::PeelingPreferences & PP)2539 void ARMTTIImpl::getPeelingPreferences(Loop *L, ScalarEvolution &SE,
2540                                        TTI::PeelingPreferences &PP) {
2541   BaseT::getPeelingPreferences(L, SE, PP);
2542 }
2543 
preferInLoopReduction(unsigned Opcode,Type * Ty,TTI::ReductionFlags Flags) const2544 bool ARMTTIImpl::preferInLoopReduction(unsigned Opcode, Type *Ty,
2545                                        TTI::ReductionFlags Flags) const {
2546   if (!ST->hasMVEIntegerOps())
2547     return false;
2548 
2549   unsigned ScalarBits = Ty->getScalarSizeInBits();
2550   switch (Opcode) {
2551   case Instruction::Add:
2552     return ScalarBits <= 64;
2553   default:
2554     return false;
2555   }
2556 }
2557 
preferPredicatedReductionSelect(unsigned Opcode,Type * Ty,TTI::ReductionFlags Flags) const2558 bool ARMTTIImpl::preferPredicatedReductionSelect(
2559     unsigned Opcode, Type *Ty, TTI::ReductionFlags Flags) const {
2560   if (!ST->hasMVEIntegerOps())
2561     return false;
2562   return true;
2563 }
2564 
getScalingFactorCost(Type * Ty,GlobalValue * BaseGV,int64_t BaseOffset,bool HasBaseReg,int64_t Scale,unsigned AddrSpace) const2565 InstructionCost ARMTTIImpl::getScalingFactorCost(Type *Ty, GlobalValue *BaseGV,
2566                                                  int64_t BaseOffset,
2567                                                  bool HasBaseReg, int64_t Scale,
2568                                                  unsigned AddrSpace) const {
2569   TargetLoweringBase::AddrMode AM;
2570   AM.BaseGV = BaseGV;
2571   AM.BaseOffs = BaseOffset;
2572   AM.HasBaseReg = HasBaseReg;
2573   AM.Scale = Scale;
2574   if (getTLI()->isLegalAddressingMode(DL, AM, Ty, AddrSpace)) {
2575     if (ST->hasFPAO())
2576       return AM.Scale < 0 ? 1 : 0; // positive offsets execute faster
2577     return 0;
2578   }
2579   return -1;
2580 }
2581 
hasArmWideBranch(bool Thumb) const2582 bool ARMTTIImpl::hasArmWideBranch(bool Thumb) const {
2583   if (Thumb) {
2584     // B.W is available in any Thumb2-supporting target, and also in every
2585     // version of Armv8-M, even Baseline which does not include the rest of
2586     // Thumb2.
2587     return ST->isThumb2() || ST->hasV8MBaselineOps();
2588   } else {
2589     // B is available in all versions of the Arm ISA, so the only question is
2590     // whether that ISA is available at all.
2591     return ST->hasARMOps();
2592   }
2593 }
2594