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/ValueTypes.h" 18 #include "llvm/IR/BasicBlock.h" 19 #include "llvm/IR/DataLayout.h" 20 #include "llvm/IR/DerivedTypes.h" 21 #include "llvm/IR/Instruction.h" 22 #include "llvm/IR/Instructions.h" 23 #include "llvm/IR/Intrinsics.h" 24 #include "llvm/IR/IntrinsicInst.h" 25 #include "llvm/IR/IntrinsicsARM.h" 26 #include "llvm/IR/PatternMatch.h" 27 #include "llvm/IR/Type.h" 28 #include "llvm/MC/SubtargetFeature.h" 29 #include "llvm/Support/Casting.h" 30 #include "llvm/Support/KnownBits.h" 31 #include "llvm/Support/MachineValueType.h" 32 #include "llvm/Target/TargetMachine.h" 33 #include "llvm/Transforms/InstCombine/InstCombiner.h" 34 #include "llvm/Transforms/Utils/Local.h" 35 #include "llvm/Transforms/Utils/LoopUtils.h" 36 #include <algorithm> 37 #include <cassert> 38 #include <cstdint> 39 #include <utility> 40 41 using namespace llvm; 42 43 #define DEBUG_TYPE "armtti" 44 45 static cl::opt<bool> EnableMaskedLoadStores( 46 "enable-arm-maskedldst", cl::Hidden, cl::init(true), 47 cl::desc("Enable the generation of masked loads and stores")); 48 49 static cl::opt<bool> DisableLowOverheadLoops( 50 "disable-arm-loloops", cl::Hidden, cl::init(false), 51 cl::desc("Disable the generation of low-overhead loops")); 52 53 static cl::opt<bool> 54 AllowWLSLoops("allow-arm-wlsloops", cl::Hidden, cl::init(true), 55 cl::desc("Enable the generation of WLS loops")); 56 57 extern cl::opt<TailPredication::Mode> EnableTailPredication; 58 59 extern cl::opt<bool> EnableMaskedGatherScatters; 60 61 extern cl::opt<unsigned> MVEMaxSupportedInterleaveFactor; 62 63 /// Convert a vector load intrinsic into a simple llvm load instruction. 64 /// This is beneficial when the underlying object being addressed comes 65 /// from a constant, since we get constant-folding for free. 66 static Value *simplifyNeonVld1(const IntrinsicInst &II, unsigned MemAlign, 67 InstCombiner::BuilderTy &Builder) { 68 auto *IntrAlign = dyn_cast<ConstantInt>(II.getArgOperand(1)); 69 70 if (!IntrAlign) 71 return nullptr; 72 73 unsigned Alignment = IntrAlign->getLimitedValue() < MemAlign 74 ? MemAlign 75 : IntrAlign->getLimitedValue(); 76 77 if (!isPowerOf2_32(Alignment)) 78 return nullptr; 79 80 auto *BCastInst = Builder.CreateBitCast(II.getArgOperand(0), 81 PointerType::get(II.getType(), 0)); 82 return Builder.CreateAlignedLoad(II.getType(), BCastInst, Align(Alignment)); 83 } 84 85 bool ARMTTIImpl::areInlineCompatible(const Function *Caller, 86 const Function *Callee) const { 87 const TargetMachine &TM = getTLI()->getTargetMachine(); 88 const FeatureBitset &CallerBits = 89 TM.getSubtargetImpl(*Caller)->getFeatureBits(); 90 const FeatureBitset &CalleeBits = 91 TM.getSubtargetImpl(*Callee)->getFeatureBits(); 92 93 // To inline a callee, all features not in the allowed list must match exactly. 94 bool MatchExact = (CallerBits & ~InlineFeaturesAllowed) == 95 (CalleeBits & ~InlineFeaturesAllowed); 96 // For features in the allowed list, the callee's features must be a subset of 97 // the callers'. 98 bool MatchSubset = ((CallerBits & CalleeBits) & InlineFeaturesAllowed) == 99 (CalleeBits & InlineFeaturesAllowed); 100 return MatchExact && MatchSubset; 101 } 102 103 bool ARMTTIImpl::shouldFavorBackedgeIndex(const Loop *L) const { 104 if (L->getHeader()->getParent()->hasOptSize()) 105 return false; 106 if (ST->hasMVEIntegerOps()) 107 return false; 108 return ST->isMClass() && ST->isThumb2() && L->getNumBlocks() == 1; 109 } 110 111 bool ARMTTIImpl::shouldFavorPostInc() const { 112 if (ST->hasMVEIntegerOps()) 113 return true; 114 return false; 115 } 116 117 Optional<Instruction *> 118 ARMTTIImpl::instCombineIntrinsic(InstCombiner &IC, IntrinsicInst &II) const { 119 using namespace PatternMatch; 120 Intrinsic::ID IID = II.getIntrinsicID(); 121 switch (IID) { 122 default: 123 break; 124 case Intrinsic::arm_neon_vld1: { 125 Align MemAlign = 126 getKnownAlignment(II.getArgOperand(0), IC.getDataLayout(), &II, 127 &IC.getAssumptionCache(), &IC.getDominatorTree()); 128 if (Value *V = simplifyNeonVld1(II, MemAlign.value(), IC.Builder)) { 129 return IC.replaceInstUsesWith(II, V); 130 } 131 break; 132 } 133 134 case Intrinsic::arm_neon_vld2: 135 case Intrinsic::arm_neon_vld3: 136 case Intrinsic::arm_neon_vld4: 137 case Intrinsic::arm_neon_vld2lane: 138 case Intrinsic::arm_neon_vld3lane: 139 case Intrinsic::arm_neon_vld4lane: 140 case Intrinsic::arm_neon_vst1: 141 case Intrinsic::arm_neon_vst2: 142 case Intrinsic::arm_neon_vst3: 143 case Intrinsic::arm_neon_vst4: 144 case Intrinsic::arm_neon_vst2lane: 145 case Intrinsic::arm_neon_vst3lane: 146 case Intrinsic::arm_neon_vst4lane: { 147 Align MemAlign = 148 getKnownAlignment(II.getArgOperand(0), IC.getDataLayout(), &II, 149 &IC.getAssumptionCache(), &IC.getDominatorTree()); 150 unsigned AlignArg = II.getNumArgOperands() - 1; 151 Value *AlignArgOp = II.getArgOperand(AlignArg); 152 MaybeAlign Align = cast<ConstantInt>(AlignArgOp)->getMaybeAlignValue(); 153 if (Align && *Align < MemAlign) { 154 return IC.replaceOperand( 155 II, AlignArg, 156 ConstantInt::get(Type::getInt32Ty(II.getContext()), MemAlign.value(), 157 false)); 158 } 159 break; 160 } 161 162 case Intrinsic::arm_mve_pred_i2v: { 163 Value *Arg = II.getArgOperand(0); 164 Value *ArgArg; 165 if (match(Arg, PatternMatch::m_Intrinsic<Intrinsic::arm_mve_pred_v2i>( 166 PatternMatch::m_Value(ArgArg))) && 167 II.getType() == ArgArg->getType()) { 168 return IC.replaceInstUsesWith(II, ArgArg); 169 } 170 Constant *XorMask; 171 if (match(Arg, m_Xor(PatternMatch::m_Intrinsic<Intrinsic::arm_mve_pred_v2i>( 172 PatternMatch::m_Value(ArgArg)), 173 PatternMatch::m_Constant(XorMask))) && 174 II.getType() == ArgArg->getType()) { 175 if (auto *CI = dyn_cast<ConstantInt>(XorMask)) { 176 if (CI->getValue().trunc(16).isAllOnesValue()) { 177 auto TrueVector = IC.Builder.CreateVectorSplat( 178 cast<FixedVectorType>(II.getType())->getNumElements(), 179 IC.Builder.getTrue()); 180 return BinaryOperator::Create(Instruction::Xor, ArgArg, TrueVector); 181 } 182 } 183 } 184 KnownBits ScalarKnown(32); 185 if (IC.SimplifyDemandedBits(&II, 0, APInt::getLowBitsSet(32, 16), 186 ScalarKnown, 0)) { 187 return &II; 188 } 189 break; 190 } 191 case Intrinsic::arm_mve_pred_v2i: { 192 Value *Arg = II.getArgOperand(0); 193 Value *ArgArg; 194 if (match(Arg, PatternMatch::m_Intrinsic<Intrinsic::arm_mve_pred_i2v>( 195 PatternMatch::m_Value(ArgArg)))) { 196 return IC.replaceInstUsesWith(II, ArgArg); 197 } 198 if (!II.getMetadata(LLVMContext::MD_range)) { 199 Type *IntTy32 = Type::getInt32Ty(II.getContext()); 200 Metadata *M[] = { 201 ConstantAsMetadata::get(ConstantInt::get(IntTy32, 0)), 202 ConstantAsMetadata::get(ConstantInt::get(IntTy32, 0xFFFF))}; 203 II.setMetadata(LLVMContext::MD_range, MDNode::get(II.getContext(), M)); 204 return &II; 205 } 206 break; 207 } 208 case Intrinsic::arm_mve_vadc: 209 case Intrinsic::arm_mve_vadc_predicated: { 210 unsigned CarryOp = 211 (II.getIntrinsicID() == Intrinsic::arm_mve_vadc_predicated) ? 3 : 2; 212 assert(II.getArgOperand(CarryOp)->getType()->getScalarSizeInBits() == 32 && 213 "Bad type for intrinsic!"); 214 215 KnownBits CarryKnown(32); 216 if (IC.SimplifyDemandedBits(&II, CarryOp, APInt::getOneBitSet(32, 29), 217 CarryKnown)) { 218 return &II; 219 } 220 break; 221 } 222 case Intrinsic::arm_mve_vmldava: { 223 Instruction *I = cast<Instruction>(&II); 224 if (I->hasOneUse()) { 225 auto *User = cast<Instruction>(*I->user_begin()); 226 Value *OpZ; 227 if (match(User, m_c_Add(m_Specific(I), m_Value(OpZ))) && 228 match(I->getOperand(3), m_Zero())) { 229 Value *OpX = I->getOperand(4); 230 Value *OpY = I->getOperand(5); 231 Type *OpTy = OpX->getType(); 232 233 IC.Builder.SetInsertPoint(User); 234 Value *V = 235 IC.Builder.CreateIntrinsic(Intrinsic::arm_mve_vmldava, {OpTy}, 236 {I->getOperand(0), I->getOperand(1), 237 I->getOperand(2), OpZ, OpX, OpY}); 238 239 IC.replaceInstUsesWith(*User, V); 240 return IC.eraseInstFromFunction(*User); 241 } 242 } 243 return None; 244 } 245 } 246 return None; 247 } 248 249 int ARMTTIImpl::getIntImmCost(const APInt &Imm, Type *Ty, 250 TTI::TargetCostKind CostKind) { 251 assert(Ty->isIntegerTy()); 252 253 unsigned Bits = Ty->getPrimitiveSizeInBits(); 254 if (Bits == 0 || Imm.getActiveBits() >= 64) 255 return 4; 256 257 int64_t SImmVal = Imm.getSExtValue(); 258 uint64_t ZImmVal = Imm.getZExtValue(); 259 if (!ST->isThumb()) { 260 if ((SImmVal >= 0 && SImmVal < 65536) || 261 (ARM_AM::getSOImmVal(ZImmVal) != -1) || 262 (ARM_AM::getSOImmVal(~ZImmVal) != -1)) 263 return 1; 264 return ST->hasV6T2Ops() ? 2 : 3; 265 } 266 if (ST->isThumb2()) { 267 if ((SImmVal >= 0 && SImmVal < 65536) || 268 (ARM_AM::getT2SOImmVal(ZImmVal) != -1) || 269 (ARM_AM::getT2SOImmVal(~ZImmVal) != -1)) 270 return 1; 271 return ST->hasV6T2Ops() ? 2 : 3; 272 } 273 // Thumb1, any i8 imm cost 1. 274 if (Bits == 8 || (SImmVal >= 0 && SImmVal < 256)) 275 return 1; 276 if ((~SImmVal < 256) || ARM_AM::isThumbImmShiftedVal(ZImmVal)) 277 return 2; 278 // Load from constantpool. 279 return 3; 280 } 281 282 // Constants smaller than 256 fit in the immediate field of 283 // Thumb1 instructions so we return a zero cost and 1 otherwise. 284 int ARMTTIImpl::getIntImmCodeSizeCost(unsigned Opcode, unsigned Idx, 285 const APInt &Imm, Type *Ty) { 286 if (Imm.isNonNegative() && Imm.getLimitedValue() < 256) 287 return 0; 288 289 return 1; 290 } 291 292 // Checks whether Inst is part of a min(max()) or max(min()) pattern 293 // that will match to an SSAT instruction 294 static bool isSSATMinMaxPattern(Instruction *Inst, const APInt &Imm) { 295 Value *LHS, *RHS; 296 ConstantInt *C; 297 SelectPatternFlavor InstSPF = matchSelectPattern(Inst, LHS, RHS).Flavor; 298 299 if (InstSPF == SPF_SMAX && 300 PatternMatch::match(RHS, PatternMatch::m_ConstantInt(C)) && 301 C->getValue() == Imm && Imm.isNegative() && (-Imm).isPowerOf2()) { 302 303 auto isSSatMin = [&](Value *MinInst) { 304 if (isa<SelectInst>(MinInst)) { 305 Value *MinLHS, *MinRHS; 306 ConstantInt *MinC; 307 SelectPatternFlavor MinSPF = 308 matchSelectPattern(MinInst, MinLHS, MinRHS).Flavor; 309 if (MinSPF == SPF_SMIN && 310 PatternMatch::match(MinRHS, PatternMatch::m_ConstantInt(MinC)) && 311 MinC->getValue() == ((-Imm) - 1)) 312 return true; 313 } 314 return false; 315 }; 316 317 if (isSSatMin(Inst->getOperand(1)) || 318 (Inst->hasNUses(2) && (isSSatMin(*Inst->user_begin()) || 319 isSSatMin(*(++Inst->user_begin()))))) 320 return true; 321 } 322 return false; 323 } 324 325 int ARMTTIImpl::getIntImmCostInst(unsigned Opcode, unsigned Idx, 326 const APInt &Imm, Type *Ty, 327 TTI::TargetCostKind CostKind, 328 Instruction *Inst) { 329 // Division by a constant can be turned into multiplication, but only if we 330 // know it's constant. So it's not so much that the immediate is cheap (it's 331 // not), but that the alternative is worse. 332 // FIXME: this is probably unneeded with GlobalISel. 333 if ((Opcode == Instruction::SDiv || Opcode == Instruction::UDiv || 334 Opcode == Instruction::SRem || Opcode == Instruction::URem) && 335 Idx == 1) 336 return 0; 337 338 if (Opcode == Instruction::And) { 339 // UXTB/UXTH 340 if (Imm == 255 || Imm == 65535) 341 return 0; 342 // Conversion to BIC is free, and means we can use ~Imm instead. 343 return std::min(getIntImmCost(Imm, Ty, CostKind), 344 getIntImmCost(~Imm, Ty, CostKind)); 345 } 346 347 if (Opcode == Instruction::Add) 348 // Conversion to SUB is free, and means we can use -Imm instead. 349 return std::min(getIntImmCost(Imm, Ty, CostKind), 350 getIntImmCost(-Imm, Ty, CostKind)); 351 352 if (Opcode == Instruction::ICmp && Imm.isNegative() && 353 Ty->getIntegerBitWidth() == 32) { 354 int64_t NegImm = -Imm.getSExtValue(); 355 if (ST->isThumb2() && NegImm < 1<<12) 356 // icmp X, #-C -> cmn X, #C 357 return 0; 358 if (ST->isThumb() && NegImm < 1<<8) 359 // icmp X, #-C -> adds X, #C 360 return 0; 361 } 362 363 // xor a, -1 can always be folded to MVN 364 if (Opcode == Instruction::Xor && Imm.isAllOnesValue()) 365 return 0; 366 367 // Ensures negative constant of min(max()) or max(min()) patterns that 368 // match to SSAT instructions don't get hoisted 369 if (Inst && ((ST->hasV6Ops() && !ST->isThumb()) || ST->isThumb2()) && 370 Ty->getIntegerBitWidth() <= 32) { 371 if (isSSATMinMaxPattern(Inst, Imm) || 372 (isa<ICmpInst>(Inst) && Inst->hasOneUse() && 373 isSSATMinMaxPattern(cast<Instruction>(*Inst->user_begin()), Imm))) 374 return 0; 375 } 376 377 return getIntImmCost(Imm, Ty, CostKind); 378 } 379 380 int ARMTTIImpl::getCFInstrCost(unsigned Opcode, TTI::TargetCostKind CostKind) { 381 if (CostKind == TTI::TCK_RecipThroughput && 382 (ST->hasNEON() || ST->hasMVEIntegerOps())) { 383 // FIXME: The vectorizer is highly sensistive to the cost of these 384 // instructions, which suggests that it may be using the costs incorrectly. 385 // But, for now, just make them free to avoid performance regressions for 386 // vector targets. 387 return 0; 388 } 389 return BaseT::getCFInstrCost(Opcode, CostKind); 390 } 391 392 int ARMTTIImpl::getCastInstrCost(unsigned Opcode, Type *Dst, Type *Src, 393 TTI::CastContextHint CCH, 394 TTI::TargetCostKind CostKind, 395 const Instruction *I) { 396 int ISD = TLI->InstructionOpcodeToISD(Opcode); 397 assert(ISD && "Invalid opcode"); 398 399 // TODO: Allow non-throughput costs that aren't binary. 400 auto AdjustCost = [&CostKind](int Cost) { 401 if (CostKind != TTI::TCK_RecipThroughput) 402 return Cost == 0 ? 0 : 1; 403 return Cost; 404 }; 405 auto IsLegalFPType = [this](EVT VT) { 406 EVT EltVT = VT.getScalarType(); 407 return (EltVT == MVT::f32 && ST->hasVFP2Base()) || 408 (EltVT == MVT::f64 && ST->hasFP64()) || 409 (EltVT == MVT::f16 && ST->hasFullFP16()); 410 }; 411 412 EVT SrcTy = TLI->getValueType(DL, Src); 413 EVT DstTy = TLI->getValueType(DL, Dst); 414 415 if (!SrcTy.isSimple() || !DstTy.isSimple()) 416 return AdjustCost( 417 BaseT::getCastInstrCost(Opcode, Dst, Src, CCH, CostKind, I)); 418 419 // Extending masked load/Truncating masked stores is expensive because we 420 // currently don't split them. This means that we'll likely end up 421 // loading/storing each element individually (hence the high cost). 422 if ((ST->hasMVEIntegerOps() && 423 (Opcode == Instruction::Trunc || Opcode == Instruction::ZExt || 424 Opcode == Instruction::SExt)) || 425 (ST->hasMVEFloatOps() && 426 (Opcode == Instruction::FPExt || Opcode == Instruction::FPTrunc) && 427 IsLegalFPType(SrcTy) && IsLegalFPType(DstTy))) 428 if (CCH == TTI::CastContextHint::Masked && DstTy.getSizeInBits() > 128) 429 return 2 * DstTy.getVectorNumElements() * ST->getMVEVectorCostFactor(); 430 431 // The extend of other kinds of load is free 432 if (CCH == TTI::CastContextHint::Normal || 433 CCH == TTI::CastContextHint::Masked) { 434 static const TypeConversionCostTblEntry LoadConversionTbl[] = { 435 {ISD::SIGN_EXTEND, MVT::i32, MVT::i16, 0}, 436 {ISD::ZERO_EXTEND, MVT::i32, MVT::i16, 0}, 437 {ISD::SIGN_EXTEND, MVT::i32, MVT::i8, 0}, 438 {ISD::ZERO_EXTEND, MVT::i32, MVT::i8, 0}, 439 {ISD::SIGN_EXTEND, MVT::i16, MVT::i8, 0}, 440 {ISD::ZERO_EXTEND, MVT::i16, MVT::i8, 0}, 441 {ISD::SIGN_EXTEND, MVT::i64, MVT::i32, 1}, 442 {ISD::ZERO_EXTEND, MVT::i64, MVT::i32, 1}, 443 {ISD::SIGN_EXTEND, MVT::i64, MVT::i16, 1}, 444 {ISD::ZERO_EXTEND, MVT::i64, MVT::i16, 1}, 445 {ISD::SIGN_EXTEND, MVT::i64, MVT::i8, 1}, 446 {ISD::ZERO_EXTEND, MVT::i64, MVT::i8, 1}, 447 }; 448 if (const auto *Entry = ConvertCostTableLookup( 449 LoadConversionTbl, ISD, DstTy.getSimpleVT(), SrcTy.getSimpleVT())) 450 return AdjustCost(Entry->Cost); 451 452 static const TypeConversionCostTblEntry MVELoadConversionTbl[] = { 453 {ISD::SIGN_EXTEND, MVT::v4i32, MVT::v4i16, 0}, 454 {ISD::ZERO_EXTEND, MVT::v4i32, MVT::v4i16, 0}, 455 {ISD::SIGN_EXTEND, MVT::v4i32, MVT::v4i8, 0}, 456 {ISD::ZERO_EXTEND, MVT::v4i32, MVT::v4i8, 0}, 457 {ISD::SIGN_EXTEND, MVT::v8i16, MVT::v8i8, 0}, 458 {ISD::ZERO_EXTEND, MVT::v8i16, MVT::v8i8, 0}, 459 // The following extend from a legal type to an illegal type, so need to 460 // split the load. This introduced an extra load operation, but the 461 // extend is still "free". 462 {ISD::SIGN_EXTEND, MVT::v8i32, MVT::v8i16, 1}, 463 {ISD::ZERO_EXTEND, MVT::v8i32, MVT::v8i16, 1}, 464 {ISD::SIGN_EXTEND, MVT::v16i32, MVT::v16i8, 3}, 465 {ISD::ZERO_EXTEND, MVT::v16i32, MVT::v16i8, 3}, 466 {ISD::SIGN_EXTEND, MVT::v16i16, MVT::v16i8, 1}, 467 {ISD::ZERO_EXTEND, MVT::v16i16, MVT::v16i8, 1}, 468 }; 469 if (SrcTy.isVector() && ST->hasMVEIntegerOps()) { 470 if (const auto *Entry = 471 ConvertCostTableLookup(MVELoadConversionTbl, ISD, 472 DstTy.getSimpleVT(), SrcTy.getSimpleVT())) 473 return AdjustCost(Entry->Cost * ST->getMVEVectorCostFactor()); 474 } 475 476 static const TypeConversionCostTblEntry MVEFLoadConversionTbl[] = { 477 // FPExtends are similar but also require the VCVT instructions. 478 {ISD::FP_EXTEND, MVT::v4f32, MVT::v4f16, 1}, 479 {ISD::FP_EXTEND, MVT::v8f32, MVT::v8f16, 3}, 480 }; 481 if (SrcTy.isVector() && ST->hasMVEFloatOps()) { 482 if (const auto *Entry = 483 ConvertCostTableLookup(MVEFLoadConversionTbl, ISD, 484 DstTy.getSimpleVT(), SrcTy.getSimpleVT())) 485 return AdjustCost(Entry->Cost * ST->getMVEVectorCostFactor()); 486 } 487 488 // The truncate of a store is free. This is the mirror of extends above. 489 static const TypeConversionCostTblEntry MVEStoreConversionTbl[] = { 490 {ISD::TRUNCATE, MVT::v4i32, MVT::v4i16, 0}, 491 {ISD::TRUNCATE, MVT::v4i32, MVT::v4i8, 0}, 492 {ISD::TRUNCATE, MVT::v8i16, MVT::v8i8, 0}, 493 {ISD::TRUNCATE, MVT::v8i32, MVT::v8i16, 1}, 494 {ISD::TRUNCATE, MVT::v8i32, MVT::v8i8, 1}, 495 {ISD::TRUNCATE, MVT::v16i32, MVT::v16i8, 3}, 496 {ISD::TRUNCATE, MVT::v16i16, MVT::v16i8, 1}, 497 }; 498 if (SrcTy.isVector() && ST->hasMVEIntegerOps()) { 499 if (const auto *Entry = 500 ConvertCostTableLookup(MVEStoreConversionTbl, ISD, 501 SrcTy.getSimpleVT(), DstTy.getSimpleVT())) 502 return AdjustCost(Entry->Cost * ST->getMVEVectorCostFactor()); 503 } 504 505 static const TypeConversionCostTblEntry MVEFStoreConversionTbl[] = { 506 {ISD::FP_ROUND, MVT::v4f32, MVT::v4f16, 1}, 507 {ISD::FP_ROUND, MVT::v8f32, MVT::v8f16, 3}, 508 }; 509 if (SrcTy.isVector() && ST->hasMVEFloatOps()) { 510 if (const auto *Entry = 511 ConvertCostTableLookup(MVEFStoreConversionTbl, ISD, 512 SrcTy.getSimpleVT(), DstTy.getSimpleVT())) 513 return AdjustCost(Entry->Cost * ST->getMVEVectorCostFactor()); 514 } 515 } 516 517 // NEON vector operations that can extend their inputs. 518 if ((ISD == ISD::SIGN_EXTEND || ISD == ISD::ZERO_EXTEND) && 519 I && I->hasOneUse() && ST->hasNEON() && SrcTy.isVector()) { 520 static const TypeConversionCostTblEntry NEONDoubleWidthTbl[] = { 521 // vaddl 522 { ISD::ADD, MVT::v4i32, MVT::v4i16, 0 }, 523 { ISD::ADD, MVT::v8i16, MVT::v8i8, 0 }, 524 // vsubl 525 { ISD::SUB, MVT::v4i32, MVT::v4i16, 0 }, 526 { ISD::SUB, MVT::v8i16, MVT::v8i8, 0 }, 527 // vmull 528 { ISD::MUL, MVT::v4i32, MVT::v4i16, 0 }, 529 { ISD::MUL, MVT::v8i16, MVT::v8i8, 0 }, 530 // vshll 531 { ISD::SHL, MVT::v4i32, MVT::v4i16, 0 }, 532 { ISD::SHL, MVT::v8i16, MVT::v8i8, 0 }, 533 }; 534 535 auto *User = cast<Instruction>(*I->user_begin()); 536 int UserISD = TLI->InstructionOpcodeToISD(User->getOpcode()); 537 if (auto *Entry = ConvertCostTableLookup(NEONDoubleWidthTbl, UserISD, 538 DstTy.getSimpleVT(), 539 SrcTy.getSimpleVT())) { 540 return AdjustCost(Entry->Cost); 541 } 542 } 543 544 // Single to/from double precision conversions. 545 if (Src->isVectorTy() && ST->hasNEON() && 546 ((ISD == ISD::FP_ROUND && SrcTy.getScalarType() == MVT::f64 && 547 DstTy.getScalarType() == MVT::f32) || 548 (ISD == ISD::FP_EXTEND && SrcTy.getScalarType() == MVT::f32 && 549 DstTy.getScalarType() == MVT::f64))) { 550 static const CostTblEntry NEONFltDblTbl[] = { 551 // Vector fptrunc/fpext conversions. 552 {ISD::FP_ROUND, MVT::v2f64, 2}, 553 {ISD::FP_EXTEND, MVT::v2f32, 2}, 554 {ISD::FP_EXTEND, MVT::v4f32, 4}}; 555 556 std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, Src); 557 if (const auto *Entry = CostTableLookup(NEONFltDblTbl, ISD, LT.second)) 558 return AdjustCost(LT.first * Entry->Cost); 559 } 560 561 // Some arithmetic, load and store operations have specific instructions 562 // to cast up/down their types automatically at no extra cost. 563 // TODO: Get these tables to know at least what the related operations are. 564 static const TypeConversionCostTblEntry NEONVectorConversionTbl[] = { 565 { ISD::SIGN_EXTEND, MVT::v4i32, MVT::v4i16, 1 }, 566 { ISD::ZERO_EXTEND, MVT::v4i32, MVT::v4i16, 1 }, 567 { ISD::SIGN_EXTEND, MVT::v2i64, MVT::v2i32, 1 }, 568 { ISD::ZERO_EXTEND, MVT::v2i64, MVT::v2i32, 1 }, 569 { ISD::TRUNCATE, MVT::v4i32, MVT::v4i64, 0 }, 570 { ISD::TRUNCATE, MVT::v4i16, MVT::v4i32, 1 }, 571 572 // The number of vmovl instructions for the extension. 573 { ISD::SIGN_EXTEND, MVT::v8i16, MVT::v8i8, 1 }, 574 { ISD::ZERO_EXTEND, MVT::v8i16, MVT::v8i8, 1 }, 575 { ISD::SIGN_EXTEND, MVT::v4i32, MVT::v4i8, 2 }, 576 { ISD::ZERO_EXTEND, MVT::v4i32, MVT::v4i8, 2 }, 577 { ISD::SIGN_EXTEND, MVT::v2i64, MVT::v2i8, 3 }, 578 { ISD::ZERO_EXTEND, MVT::v2i64, MVT::v2i8, 3 }, 579 { ISD::SIGN_EXTEND, MVT::v2i64, MVT::v2i16, 2 }, 580 { ISD::ZERO_EXTEND, MVT::v2i64, MVT::v2i16, 2 }, 581 { ISD::SIGN_EXTEND, MVT::v4i64, MVT::v4i16, 3 }, 582 { ISD::ZERO_EXTEND, MVT::v4i64, MVT::v4i16, 3 }, 583 { ISD::SIGN_EXTEND, MVT::v8i32, MVT::v8i8, 3 }, 584 { ISD::ZERO_EXTEND, MVT::v8i32, MVT::v8i8, 3 }, 585 { ISD::SIGN_EXTEND, MVT::v8i64, MVT::v8i8, 7 }, 586 { ISD::ZERO_EXTEND, MVT::v8i64, MVT::v8i8, 7 }, 587 { ISD::SIGN_EXTEND, MVT::v8i64, MVT::v8i16, 6 }, 588 { ISD::ZERO_EXTEND, MVT::v8i64, MVT::v8i16, 6 }, 589 { ISD::SIGN_EXTEND, MVT::v16i32, MVT::v16i8, 6 }, 590 { ISD::ZERO_EXTEND, MVT::v16i32, MVT::v16i8, 6 }, 591 592 // Operations that we legalize using splitting. 593 { ISD::TRUNCATE, MVT::v16i8, MVT::v16i32, 6 }, 594 { ISD::TRUNCATE, MVT::v8i8, MVT::v8i32, 3 }, 595 596 // Vector float <-> i32 conversions. 597 { ISD::SINT_TO_FP, MVT::v4f32, MVT::v4i32, 1 }, 598 { ISD::UINT_TO_FP, MVT::v4f32, MVT::v4i32, 1 }, 599 600 { ISD::SINT_TO_FP, MVT::v2f32, MVT::v2i8, 3 }, 601 { ISD::UINT_TO_FP, MVT::v2f32, MVT::v2i8, 3 }, 602 { ISD::SINT_TO_FP, MVT::v2f32, MVT::v2i16, 2 }, 603 { ISD::UINT_TO_FP, MVT::v2f32, MVT::v2i16, 2 }, 604 { ISD::SINT_TO_FP, MVT::v2f32, MVT::v2i32, 1 }, 605 { ISD::UINT_TO_FP, MVT::v2f32, MVT::v2i32, 1 }, 606 { ISD::SINT_TO_FP, MVT::v4f32, MVT::v4i1, 3 }, 607 { ISD::UINT_TO_FP, MVT::v4f32, MVT::v4i1, 3 }, 608 { ISD::SINT_TO_FP, MVT::v4f32, MVT::v4i8, 3 }, 609 { ISD::UINT_TO_FP, MVT::v4f32, MVT::v4i8, 3 }, 610 { ISD::SINT_TO_FP, MVT::v4f32, MVT::v4i16, 2 }, 611 { ISD::UINT_TO_FP, MVT::v4f32, MVT::v4i16, 2 }, 612 { ISD::SINT_TO_FP, MVT::v8f32, MVT::v8i16, 4 }, 613 { ISD::UINT_TO_FP, MVT::v8f32, MVT::v8i16, 4 }, 614 { ISD::SINT_TO_FP, MVT::v8f32, MVT::v8i32, 2 }, 615 { ISD::UINT_TO_FP, MVT::v8f32, MVT::v8i32, 2 }, 616 { ISD::SINT_TO_FP, MVT::v16f32, MVT::v16i16, 8 }, 617 { ISD::UINT_TO_FP, MVT::v16f32, MVT::v16i16, 8 }, 618 { ISD::SINT_TO_FP, MVT::v16f32, MVT::v16i32, 4 }, 619 { ISD::UINT_TO_FP, MVT::v16f32, MVT::v16i32, 4 }, 620 621 { ISD::FP_TO_SINT, MVT::v4i32, MVT::v4f32, 1 }, 622 { ISD::FP_TO_UINT, MVT::v4i32, MVT::v4f32, 1 }, 623 { ISD::FP_TO_SINT, MVT::v4i8, MVT::v4f32, 3 }, 624 { ISD::FP_TO_UINT, MVT::v4i8, MVT::v4f32, 3 }, 625 { ISD::FP_TO_SINT, MVT::v4i16, MVT::v4f32, 2 }, 626 { ISD::FP_TO_UINT, MVT::v4i16, MVT::v4f32, 2 }, 627 628 // Vector double <-> i32 conversions. 629 { ISD::SINT_TO_FP, MVT::v2f64, MVT::v2i32, 2 }, 630 { ISD::UINT_TO_FP, MVT::v2f64, MVT::v2i32, 2 }, 631 632 { ISD::SINT_TO_FP, MVT::v2f64, MVT::v2i8, 4 }, 633 { ISD::UINT_TO_FP, MVT::v2f64, MVT::v2i8, 4 }, 634 { ISD::SINT_TO_FP, MVT::v2f64, MVT::v2i16, 3 }, 635 { ISD::UINT_TO_FP, MVT::v2f64, MVT::v2i16, 3 }, 636 { ISD::SINT_TO_FP, MVT::v2f64, MVT::v2i32, 2 }, 637 { ISD::UINT_TO_FP, MVT::v2f64, MVT::v2i32, 2 }, 638 639 { ISD::FP_TO_SINT, MVT::v2i32, MVT::v2f64, 2 }, 640 { ISD::FP_TO_UINT, MVT::v2i32, MVT::v2f64, 2 }, 641 { ISD::FP_TO_SINT, MVT::v8i16, MVT::v8f32, 4 }, 642 { ISD::FP_TO_UINT, MVT::v8i16, MVT::v8f32, 4 }, 643 { ISD::FP_TO_SINT, MVT::v16i16, MVT::v16f32, 8 }, 644 { ISD::FP_TO_UINT, MVT::v16i16, MVT::v16f32, 8 } 645 }; 646 647 if (SrcTy.isVector() && ST->hasNEON()) { 648 if (const auto *Entry = ConvertCostTableLookup(NEONVectorConversionTbl, ISD, 649 DstTy.getSimpleVT(), 650 SrcTy.getSimpleVT())) 651 return AdjustCost(Entry->Cost); 652 } 653 654 // Scalar float to integer conversions. 655 static const TypeConversionCostTblEntry NEONFloatConversionTbl[] = { 656 { ISD::FP_TO_SINT, MVT::i1, MVT::f32, 2 }, 657 { ISD::FP_TO_UINT, MVT::i1, MVT::f32, 2 }, 658 { ISD::FP_TO_SINT, MVT::i1, MVT::f64, 2 }, 659 { ISD::FP_TO_UINT, MVT::i1, MVT::f64, 2 }, 660 { ISD::FP_TO_SINT, MVT::i8, MVT::f32, 2 }, 661 { ISD::FP_TO_UINT, MVT::i8, MVT::f32, 2 }, 662 { ISD::FP_TO_SINT, MVT::i8, MVT::f64, 2 }, 663 { ISD::FP_TO_UINT, MVT::i8, MVT::f64, 2 }, 664 { ISD::FP_TO_SINT, MVT::i16, MVT::f32, 2 }, 665 { ISD::FP_TO_UINT, MVT::i16, MVT::f32, 2 }, 666 { ISD::FP_TO_SINT, MVT::i16, MVT::f64, 2 }, 667 { ISD::FP_TO_UINT, MVT::i16, MVT::f64, 2 }, 668 { ISD::FP_TO_SINT, MVT::i32, MVT::f32, 2 }, 669 { ISD::FP_TO_UINT, MVT::i32, MVT::f32, 2 }, 670 { ISD::FP_TO_SINT, MVT::i32, MVT::f64, 2 }, 671 { ISD::FP_TO_UINT, MVT::i32, MVT::f64, 2 }, 672 { ISD::FP_TO_SINT, MVT::i64, MVT::f32, 10 }, 673 { ISD::FP_TO_UINT, MVT::i64, MVT::f32, 10 }, 674 { ISD::FP_TO_SINT, MVT::i64, MVT::f64, 10 }, 675 { ISD::FP_TO_UINT, MVT::i64, MVT::f64, 10 } 676 }; 677 if (SrcTy.isFloatingPoint() && ST->hasNEON()) { 678 if (const auto *Entry = ConvertCostTableLookup(NEONFloatConversionTbl, ISD, 679 DstTy.getSimpleVT(), 680 SrcTy.getSimpleVT())) 681 return AdjustCost(Entry->Cost); 682 } 683 684 // Scalar integer to float conversions. 685 static const TypeConversionCostTblEntry NEONIntegerConversionTbl[] = { 686 { ISD::SINT_TO_FP, MVT::f32, MVT::i1, 2 }, 687 { ISD::UINT_TO_FP, MVT::f32, MVT::i1, 2 }, 688 { ISD::SINT_TO_FP, MVT::f64, MVT::i1, 2 }, 689 { ISD::UINT_TO_FP, MVT::f64, MVT::i1, 2 }, 690 { ISD::SINT_TO_FP, MVT::f32, MVT::i8, 2 }, 691 { ISD::UINT_TO_FP, MVT::f32, MVT::i8, 2 }, 692 { ISD::SINT_TO_FP, MVT::f64, MVT::i8, 2 }, 693 { ISD::UINT_TO_FP, MVT::f64, MVT::i8, 2 }, 694 { ISD::SINT_TO_FP, MVT::f32, MVT::i16, 2 }, 695 { ISD::UINT_TO_FP, MVT::f32, MVT::i16, 2 }, 696 { ISD::SINT_TO_FP, MVT::f64, MVT::i16, 2 }, 697 { ISD::UINT_TO_FP, MVT::f64, MVT::i16, 2 }, 698 { ISD::SINT_TO_FP, MVT::f32, MVT::i32, 2 }, 699 { ISD::UINT_TO_FP, MVT::f32, MVT::i32, 2 }, 700 { ISD::SINT_TO_FP, MVT::f64, MVT::i32, 2 }, 701 { ISD::UINT_TO_FP, MVT::f64, MVT::i32, 2 }, 702 { ISD::SINT_TO_FP, MVT::f32, MVT::i64, 10 }, 703 { ISD::UINT_TO_FP, MVT::f32, MVT::i64, 10 }, 704 { ISD::SINT_TO_FP, MVT::f64, MVT::i64, 10 }, 705 { ISD::UINT_TO_FP, MVT::f64, MVT::i64, 10 } 706 }; 707 708 if (SrcTy.isInteger() && ST->hasNEON()) { 709 if (const auto *Entry = ConvertCostTableLookup(NEONIntegerConversionTbl, 710 ISD, DstTy.getSimpleVT(), 711 SrcTy.getSimpleVT())) 712 return AdjustCost(Entry->Cost); 713 } 714 715 // MVE extend costs, taken from codegen tests. i8->i16 or i16->i32 is one 716 // instruction, i8->i32 is two. i64 zexts are an VAND with a constant, sext 717 // are linearised so take more. 718 static const TypeConversionCostTblEntry MVEVectorConversionTbl[] = { 719 { ISD::SIGN_EXTEND, MVT::v8i16, MVT::v8i8, 1 }, 720 { ISD::ZERO_EXTEND, MVT::v8i16, MVT::v8i8, 1 }, 721 { ISD::SIGN_EXTEND, MVT::v4i32, MVT::v4i8, 2 }, 722 { ISD::ZERO_EXTEND, MVT::v4i32, MVT::v4i8, 2 }, 723 { ISD::SIGN_EXTEND, MVT::v2i64, MVT::v2i8, 10 }, 724 { ISD::ZERO_EXTEND, MVT::v2i64, MVT::v2i8, 2 }, 725 { ISD::SIGN_EXTEND, MVT::v4i32, MVT::v4i16, 1 }, 726 { ISD::ZERO_EXTEND, MVT::v4i32, MVT::v4i16, 1 }, 727 { ISD::SIGN_EXTEND, MVT::v2i64, MVT::v2i16, 10 }, 728 { ISD::ZERO_EXTEND, MVT::v2i64, MVT::v2i16, 2 }, 729 { ISD::SIGN_EXTEND, MVT::v2i64, MVT::v2i32, 8 }, 730 { ISD::ZERO_EXTEND, MVT::v2i64, MVT::v2i32, 2 }, 731 }; 732 733 if (SrcTy.isVector() && ST->hasMVEIntegerOps()) { 734 if (const auto *Entry = ConvertCostTableLookup(MVEVectorConversionTbl, 735 ISD, DstTy.getSimpleVT(), 736 SrcTy.getSimpleVT())) 737 return AdjustCost(Entry->Cost * ST->getMVEVectorCostFactor()); 738 } 739 740 if (ISD == ISD::FP_ROUND || ISD == ISD::FP_EXTEND) { 741 // As general rule, fp converts that were not matched above are scalarized 742 // and cost 1 vcvt for each lane, so long as the instruction is available. 743 // If not it will become a series of function calls. 744 const int CallCost = getCallInstrCost(nullptr, Dst, {Src}, CostKind); 745 int Lanes = 1; 746 if (SrcTy.isFixedLengthVector()) 747 Lanes = SrcTy.getVectorNumElements(); 748 749 if (IsLegalFPType(SrcTy) && IsLegalFPType(DstTy)) 750 return Lanes; 751 else 752 return Lanes * CallCost; 753 } 754 755 if (ISD == ISD::TRUNCATE && ST->hasMVEIntegerOps() && 756 SrcTy.isFixedLengthVector()) { 757 // Treat a truncate with larger than legal source (128bits for MVE) as 758 // expensive, 2 instructions per lane. 759 if ((SrcTy.getScalarType() == MVT::i8 || 760 SrcTy.getScalarType() == MVT::i16 || 761 SrcTy.getScalarType() == MVT::i32) && 762 SrcTy.getSizeInBits() > 128 && 763 SrcTy.getSizeInBits() > DstTy.getSizeInBits()) 764 return SrcTy.getVectorNumElements() * 2; 765 } 766 767 // Scalar integer conversion costs. 768 static const TypeConversionCostTblEntry ARMIntegerConversionTbl[] = { 769 // i16 -> i64 requires two dependent operations. 770 { ISD::SIGN_EXTEND, MVT::i64, MVT::i16, 2 }, 771 772 // Truncates on i64 are assumed to be free. 773 { ISD::TRUNCATE, MVT::i32, MVT::i64, 0 }, 774 { ISD::TRUNCATE, MVT::i16, MVT::i64, 0 }, 775 { ISD::TRUNCATE, MVT::i8, MVT::i64, 0 }, 776 { ISD::TRUNCATE, MVT::i1, MVT::i64, 0 } 777 }; 778 779 if (SrcTy.isInteger()) { 780 if (const auto *Entry = ConvertCostTableLookup(ARMIntegerConversionTbl, ISD, 781 DstTy.getSimpleVT(), 782 SrcTy.getSimpleVT())) 783 return AdjustCost(Entry->Cost); 784 } 785 786 int BaseCost = ST->hasMVEIntegerOps() && Src->isVectorTy() 787 ? ST->getMVEVectorCostFactor() 788 : 1; 789 return AdjustCost( 790 BaseCost * BaseT::getCastInstrCost(Opcode, Dst, Src, CCH, CostKind, I)); 791 } 792 793 int ARMTTIImpl::getVectorInstrCost(unsigned Opcode, Type *ValTy, 794 unsigned Index) { 795 // Penalize inserting into an D-subregister. We end up with a three times 796 // lower estimated throughput on swift. 797 if (ST->hasSlowLoadDSubregister() && Opcode == Instruction::InsertElement && 798 ValTy->isVectorTy() && ValTy->getScalarSizeInBits() <= 32) 799 return 3; 800 801 if (ST->hasNEON() && (Opcode == Instruction::InsertElement || 802 Opcode == Instruction::ExtractElement)) { 803 // Cross-class copies are expensive on many microarchitectures, 804 // so assume they are expensive by default. 805 if (cast<VectorType>(ValTy)->getElementType()->isIntegerTy()) 806 return 3; 807 808 // Even if it's not a cross class copy, this likely leads to mixing 809 // of NEON and VFP code and should be therefore penalized. 810 if (ValTy->isVectorTy() && 811 ValTy->getScalarSizeInBits() <= 32) 812 return std::max(BaseT::getVectorInstrCost(Opcode, ValTy, Index), 2U); 813 } 814 815 if (ST->hasMVEIntegerOps() && (Opcode == Instruction::InsertElement || 816 Opcode == Instruction::ExtractElement)) { 817 // We say MVE moves costs at least the MVEVectorCostFactor, even though 818 // they are scalar instructions. This helps prevent mixing scalar and 819 // vector, to prevent vectorising where we end up just scalarising the 820 // result anyway. 821 return std::max(BaseT::getVectorInstrCost(Opcode, ValTy, Index), 822 ST->getMVEVectorCostFactor()) * 823 cast<FixedVectorType>(ValTy)->getNumElements() / 2; 824 } 825 826 return BaseT::getVectorInstrCost(Opcode, ValTy, Index); 827 } 828 829 int ARMTTIImpl::getCmpSelInstrCost(unsigned Opcode, Type *ValTy, Type *CondTy, 830 CmpInst::Predicate VecPred, 831 TTI::TargetCostKind CostKind, 832 const Instruction *I) { 833 int ISD = TLI->InstructionOpcodeToISD(Opcode); 834 835 // Thumb scalar code size cost for select. 836 if (CostKind == TTI::TCK_CodeSize && ISD == ISD::SELECT && 837 ST->isThumb() && !ValTy->isVectorTy()) { 838 // Assume expensive structs. 839 if (TLI->getValueType(DL, ValTy, true) == MVT::Other) 840 return TTI::TCC_Expensive; 841 842 // Select costs can vary because they: 843 // - may require one or more conditional mov (including an IT), 844 // - can't operate directly on immediates, 845 // - require live flags, which we can't copy around easily. 846 int Cost = TLI->getTypeLegalizationCost(DL, ValTy).first; 847 848 // Possible IT instruction for Thumb2, or more for Thumb1. 849 ++Cost; 850 851 // i1 values may need rematerialising by using mov immediates and/or 852 // flag setting instructions. 853 if (ValTy->isIntegerTy(1)) 854 ++Cost; 855 856 return Cost; 857 } 858 859 // On NEON a vector select gets lowered to vbsl. 860 if (ST->hasNEON() && ValTy->isVectorTy() && ISD == ISD::SELECT && CondTy) { 861 // Lowering of some vector selects is currently far from perfect. 862 static const TypeConversionCostTblEntry NEONVectorSelectTbl[] = { 863 { ISD::SELECT, MVT::v4i1, MVT::v4i64, 4*4 + 1*2 + 1 }, 864 { ISD::SELECT, MVT::v8i1, MVT::v8i64, 50 }, 865 { ISD::SELECT, MVT::v16i1, MVT::v16i64, 100 } 866 }; 867 868 EVT SelCondTy = TLI->getValueType(DL, CondTy); 869 EVT SelValTy = TLI->getValueType(DL, ValTy); 870 if (SelCondTy.isSimple() && SelValTy.isSimple()) { 871 if (const auto *Entry = ConvertCostTableLookup(NEONVectorSelectTbl, ISD, 872 SelCondTy.getSimpleVT(), 873 SelValTy.getSimpleVT())) 874 return Entry->Cost; 875 } 876 877 std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, ValTy); 878 return LT.first; 879 } 880 881 // Default to cheap (throughput/size of 1 instruction) but adjust throughput 882 // for "multiple beats" potentially needed by MVE instructions. 883 int BaseCost = 1; 884 if (CostKind != TTI::TCK_CodeSize && ST->hasMVEIntegerOps() && 885 ValTy->isVectorTy()) 886 BaseCost = ST->getMVEVectorCostFactor(); 887 888 return BaseCost * 889 BaseT::getCmpSelInstrCost(Opcode, ValTy, CondTy, VecPred, CostKind, I); 890 } 891 892 int ARMTTIImpl::getAddressComputationCost(Type *Ty, ScalarEvolution *SE, 893 const SCEV *Ptr) { 894 // Address computations in vectorized code with non-consecutive addresses will 895 // likely result in more instructions compared to scalar code where the 896 // computation can more often be merged into the index mode. The resulting 897 // extra micro-ops can significantly decrease throughput. 898 unsigned NumVectorInstToHideOverhead = 10; 899 int MaxMergeDistance = 64; 900 901 if (ST->hasNEON()) { 902 if (Ty->isVectorTy() && SE && 903 !BaseT::isConstantStridedAccessLessThan(SE, Ptr, MaxMergeDistance + 1)) 904 return NumVectorInstToHideOverhead; 905 906 // In many cases the address computation is not merged into the instruction 907 // addressing mode. 908 return 1; 909 } 910 return BaseT::getAddressComputationCost(Ty, SE, Ptr); 911 } 912 913 bool ARMTTIImpl::isProfitableLSRChainElement(Instruction *I) { 914 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) { 915 // If a VCTP is part of a chain, it's already profitable and shouldn't be 916 // optimized, else LSR may block tail-predication. 917 switch (II->getIntrinsicID()) { 918 case Intrinsic::arm_mve_vctp8: 919 case Intrinsic::arm_mve_vctp16: 920 case Intrinsic::arm_mve_vctp32: 921 case Intrinsic::arm_mve_vctp64: 922 return true; 923 default: 924 break; 925 } 926 } 927 return false; 928 } 929 930 bool ARMTTIImpl::isLegalMaskedLoad(Type *DataTy, Align Alignment) { 931 if (!EnableMaskedLoadStores || !ST->hasMVEIntegerOps()) 932 return false; 933 934 if (auto *VecTy = dyn_cast<FixedVectorType>(DataTy)) { 935 // Don't support v2i1 yet. 936 if (VecTy->getNumElements() == 2) 937 return false; 938 939 // We don't support extending fp types. 940 unsigned VecWidth = DataTy->getPrimitiveSizeInBits(); 941 if (VecWidth != 128 && VecTy->getElementType()->isFloatingPointTy()) 942 return false; 943 } 944 945 unsigned EltWidth = DataTy->getScalarSizeInBits(); 946 return (EltWidth == 32 && Alignment >= 4) || 947 (EltWidth == 16 && Alignment >= 2) || (EltWidth == 8); 948 } 949 950 bool ARMTTIImpl::isLegalMaskedGather(Type *Ty, Align Alignment) { 951 if (!EnableMaskedGatherScatters || !ST->hasMVEIntegerOps()) 952 return false; 953 954 // This method is called in 2 places: 955 // - from the vectorizer with a scalar type, in which case we need to get 956 // this as good as we can with the limited info we have (and rely on the cost 957 // model for the rest). 958 // - from the masked intrinsic lowering pass with the actual vector type. 959 // For MVE, we have a custom lowering pass that will already have custom 960 // legalised any gathers that we can to MVE intrinsics, and want to expand all 961 // the rest. The pass runs before the masked intrinsic lowering pass, so if we 962 // are here, we know we want to expand. 963 if (isa<VectorType>(Ty)) 964 return false; 965 966 unsigned EltWidth = Ty->getScalarSizeInBits(); 967 return ((EltWidth == 32 && Alignment >= 4) || 968 (EltWidth == 16 && Alignment >= 2) || EltWidth == 8); 969 } 970 971 /// Given a memcpy/memset/memmove instruction, return the number of memory 972 /// operations performed, via querying findOptimalMemOpLowering. Returns -1 if a 973 /// call is used. 974 int ARMTTIImpl::getNumMemOps(const IntrinsicInst *I) const { 975 MemOp MOp; 976 unsigned DstAddrSpace = ~0u; 977 unsigned SrcAddrSpace = ~0u; 978 const Function *F = I->getParent()->getParent(); 979 980 if (const auto *MC = dyn_cast<MemTransferInst>(I)) { 981 ConstantInt *C = dyn_cast<ConstantInt>(MC->getLength()); 982 // If 'size' is not a constant, a library call will be generated. 983 if (!C) 984 return -1; 985 986 const unsigned Size = C->getValue().getZExtValue(); 987 const Align DstAlign = *MC->getDestAlign(); 988 const Align SrcAlign = *MC->getSourceAlign(); 989 990 MOp = MemOp::Copy(Size, /*DstAlignCanChange*/ false, DstAlign, SrcAlign, 991 /*IsVolatile*/ false); 992 DstAddrSpace = MC->getDestAddressSpace(); 993 SrcAddrSpace = MC->getSourceAddressSpace(); 994 } 995 else if (const auto *MS = dyn_cast<MemSetInst>(I)) { 996 ConstantInt *C = dyn_cast<ConstantInt>(MS->getLength()); 997 // If 'size' is not a constant, a library call will be generated. 998 if (!C) 999 return -1; 1000 1001 const unsigned Size = C->getValue().getZExtValue(); 1002 const Align DstAlign = *MS->getDestAlign(); 1003 1004 MOp = MemOp::Set(Size, /*DstAlignCanChange*/ false, DstAlign, 1005 /*IsZeroMemset*/ false, /*IsVolatile*/ false); 1006 DstAddrSpace = MS->getDestAddressSpace(); 1007 } 1008 else 1009 llvm_unreachable("Expected a memcpy/move or memset!"); 1010 1011 unsigned Limit, Factor = 2; 1012 switch(I->getIntrinsicID()) { 1013 case Intrinsic::memcpy: 1014 Limit = TLI->getMaxStoresPerMemcpy(F->hasMinSize()); 1015 break; 1016 case Intrinsic::memmove: 1017 Limit = TLI->getMaxStoresPerMemmove(F->hasMinSize()); 1018 break; 1019 case Intrinsic::memset: 1020 Limit = TLI->getMaxStoresPerMemset(F->hasMinSize()); 1021 Factor = 1; 1022 break; 1023 default: 1024 llvm_unreachable("Expected a memcpy/move or memset!"); 1025 } 1026 1027 // MemOps will be poplulated with a list of data types that needs to be 1028 // loaded and stored. That's why we multiply the number of elements by 2 to 1029 // get the cost for this memcpy. 1030 std::vector<EVT> MemOps; 1031 if (getTLI()->findOptimalMemOpLowering( 1032 MemOps, Limit, MOp, DstAddrSpace, 1033 SrcAddrSpace, F->getAttributes())) 1034 return MemOps.size() * Factor; 1035 1036 // If we can't find an optimal memop lowering, return the default cost 1037 return -1; 1038 } 1039 1040 int ARMTTIImpl::getMemcpyCost(const Instruction *I) { 1041 int NumOps = getNumMemOps(cast<IntrinsicInst>(I)); 1042 1043 // To model the cost of a library call, we assume 1 for the call, and 1044 // 3 for the argument setup. 1045 if (NumOps == -1) 1046 return 4; 1047 return NumOps; 1048 } 1049 1050 int ARMTTIImpl::getShuffleCost(TTI::ShuffleKind Kind, VectorType *Tp, 1051 int Index, VectorType *SubTp) { 1052 if (ST->hasNEON()) { 1053 if (Kind == TTI::SK_Broadcast) { 1054 static const CostTblEntry NEONDupTbl[] = { 1055 // VDUP handles these cases. 1056 {ISD::VECTOR_SHUFFLE, MVT::v2i32, 1}, 1057 {ISD::VECTOR_SHUFFLE, MVT::v2f32, 1}, 1058 {ISD::VECTOR_SHUFFLE, MVT::v2i64, 1}, 1059 {ISD::VECTOR_SHUFFLE, MVT::v2f64, 1}, 1060 {ISD::VECTOR_SHUFFLE, MVT::v4i16, 1}, 1061 {ISD::VECTOR_SHUFFLE, MVT::v8i8, 1}, 1062 1063 {ISD::VECTOR_SHUFFLE, MVT::v4i32, 1}, 1064 {ISD::VECTOR_SHUFFLE, MVT::v4f32, 1}, 1065 {ISD::VECTOR_SHUFFLE, MVT::v8i16, 1}, 1066 {ISD::VECTOR_SHUFFLE, MVT::v16i8, 1}}; 1067 1068 std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, Tp); 1069 1070 if (const auto *Entry = 1071 CostTableLookup(NEONDupTbl, ISD::VECTOR_SHUFFLE, LT.second)) 1072 return LT.first * Entry->Cost; 1073 } 1074 if (Kind == TTI::SK_Reverse) { 1075 static const CostTblEntry NEONShuffleTbl[] = { 1076 // Reverse shuffle cost one instruction if we are shuffling within a 1077 // double word (vrev) or two if we shuffle a quad word (vrev, vext). 1078 {ISD::VECTOR_SHUFFLE, MVT::v2i32, 1}, 1079 {ISD::VECTOR_SHUFFLE, MVT::v2f32, 1}, 1080 {ISD::VECTOR_SHUFFLE, MVT::v2i64, 1}, 1081 {ISD::VECTOR_SHUFFLE, MVT::v2f64, 1}, 1082 {ISD::VECTOR_SHUFFLE, MVT::v4i16, 1}, 1083 {ISD::VECTOR_SHUFFLE, MVT::v8i8, 1}, 1084 1085 {ISD::VECTOR_SHUFFLE, MVT::v4i32, 2}, 1086 {ISD::VECTOR_SHUFFLE, MVT::v4f32, 2}, 1087 {ISD::VECTOR_SHUFFLE, MVT::v8i16, 2}, 1088 {ISD::VECTOR_SHUFFLE, MVT::v16i8, 2}}; 1089 1090 std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, Tp); 1091 1092 if (const auto *Entry = 1093 CostTableLookup(NEONShuffleTbl, ISD::VECTOR_SHUFFLE, LT.second)) 1094 return LT.first * Entry->Cost; 1095 } 1096 if (Kind == TTI::SK_Select) { 1097 static const CostTblEntry NEONSelShuffleTbl[] = { 1098 // Select shuffle cost table for ARM. Cost is the number of 1099 // instructions 1100 // required to create the shuffled vector. 1101 1102 {ISD::VECTOR_SHUFFLE, MVT::v2f32, 1}, 1103 {ISD::VECTOR_SHUFFLE, MVT::v2i64, 1}, 1104 {ISD::VECTOR_SHUFFLE, MVT::v2f64, 1}, 1105 {ISD::VECTOR_SHUFFLE, MVT::v2i32, 1}, 1106 1107 {ISD::VECTOR_SHUFFLE, MVT::v4i32, 2}, 1108 {ISD::VECTOR_SHUFFLE, MVT::v4f32, 2}, 1109 {ISD::VECTOR_SHUFFLE, MVT::v4i16, 2}, 1110 1111 {ISD::VECTOR_SHUFFLE, MVT::v8i16, 16}, 1112 1113 {ISD::VECTOR_SHUFFLE, MVT::v16i8, 32}}; 1114 1115 std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, Tp); 1116 if (const auto *Entry = CostTableLookup(NEONSelShuffleTbl, 1117 ISD::VECTOR_SHUFFLE, LT.second)) 1118 return LT.first * Entry->Cost; 1119 } 1120 } 1121 if (ST->hasMVEIntegerOps()) { 1122 if (Kind == TTI::SK_Broadcast) { 1123 static const CostTblEntry MVEDupTbl[] = { 1124 // VDUP handles these cases. 1125 {ISD::VECTOR_SHUFFLE, MVT::v4i32, 1}, 1126 {ISD::VECTOR_SHUFFLE, MVT::v8i16, 1}, 1127 {ISD::VECTOR_SHUFFLE, MVT::v16i8, 1}, 1128 {ISD::VECTOR_SHUFFLE, MVT::v4f32, 1}, 1129 {ISD::VECTOR_SHUFFLE, MVT::v8f16, 1}}; 1130 1131 std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, Tp); 1132 1133 if (const auto *Entry = CostTableLookup(MVEDupTbl, ISD::VECTOR_SHUFFLE, 1134 LT.second)) 1135 return LT.first * Entry->Cost * ST->getMVEVectorCostFactor(); 1136 } 1137 } 1138 int BaseCost = ST->hasMVEIntegerOps() && Tp->isVectorTy() 1139 ? ST->getMVEVectorCostFactor() 1140 : 1; 1141 return BaseCost * BaseT::getShuffleCost(Kind, Tp, Index, SubTp); 1142 } 1143 1144 int ARMTTIImpl::getArithmeticInstrCost(unsigned Opcode, Type *Ty, 1145 TTI::TargetCostKind CostKind, 1146 TTI::OperandValueKind Op1Info, 1147 TTI::OperandValueKind Op2Info, 1148 TTI::OperandValueProperties Opd1PropInfo, 1149 TTI::OperandValueProperties Opd2PropInfo, 1150 ArrayRef<const Value *> Args, 1151 const Instruction *CxtI) { 1152 int ISDOpcode = TLI->InstructionOpcodeToISD(Opcode); 1153 if (ST->isThumb() && CostKind == TTI::TCK_CodeSize && Ty->isIntegerTy(1)) { 1154 // Make operations on i1 relatively expensive as this often involves 1155 // combining predicates. AND and XOR should be easier to handle with IT 1156 // blocks. 1157 switch (ISDOpcode) { 1158 default: 1159 break; 1160 case ISD::AND: 1161 case ISD::XOR: 1162 return 2; 1163 case ISD::OR: 1164 return 3; 1165 } 1166 } 1167 1168 std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, Ty); 1169 1170 if (ST->hasNEON()) { 1171 const unsigned FunctionCallDivCost = 20; 1172 const unsigned ReciprocalDivCost = 10; 1173 static const CostTblEntry CostTbl[] = { 1174 // Division. 1175 // These costs are somewhat random. Choose a cost of 20 to indicate that 1176 // vectorizing devision (added function call) is going to be very expensive. 1177 // Double registers types. 1178 { ISD::SDIV, MVT::v1i64, 1 * FunctionCallDivCost}, 1179 { ISD::UDIV, MVT::v1i64, 1 * FunctionCallDivCost}, 1180 { ISD::SREM, MVT::v1i64, 1 * FunctionCallDivCost}, 1181 { ISD::UREM, MVT::v1i64, 1 * FunctionCallDivCost}, 1182 { ISD::SDIV, MVT::v2i32, 2 * FunctionCallDivCost}, 1183 { ISD::UDIV, MVT::v2i32, 2 * FunctionCallDivCost}, 1184 { ISD::SREM, MVT::v2i32, 2 * FunctionCallDivCost}, 1185 { ISD::UREM, MVT::v2i32, 2 * FunctionCallDivCost}, 1186 { ISD::SDIV, MVT::v4i16, ReciprocalDivCost}, 1187 { ISD::UDIV, MVT::v4i16, ReciprocalDivCost}, 1188 { ISD::SREM, MVT::v4i16, 4 * FunctionCallDivCost}, 1189 { ISD::UREM, MVT::v4i16, 4 * FunctionCallDivCost}, 1190 { ISD::SDIV, MVT::v8i8, ReciprocalDivCost}, 1191 { ISD::UDIV, MVT::v8i8, ReciprocalDivCost}, 1192 { ISD::SREM, MVT::v8i8, 8 * FunctionCallDivCost}, 1193 { ISD::UREM, MVT::v8i8, 8 * FunctionCallDivCost}, 1194 // Quad register types. 1195 { ISD::SDIV, MVT::v2i64, 2 * FunctionCallDivCost}, 1196 { ISD::UDIV, MVT::v2i64, 2 * FunctionCallDivCost}, 1197 { ISD::SREM, MVT::v2i64, 2 * FunctionCallDivCost}, 1198 { ISD::UREM, MVT::v2i64, 2 * FunctionCallDivCost}, 1199 { ISD::SDIV, MVT::v4i32, 4 * FunctionCallDivCost}, 1200 { ISD::UDIV, MVT::v4i32, 4 * FunctionCallDivCost}, 1201 { ISD::SREM, MVT::v4i32, 4 * FunctionCallDivCost}, 1202 { ISD::UREM, MVT::v4i32, 4 * FunctionCallDivCost}, 1203 { ISD::SDIV, MVT::v8i16, 8 * FunctionCallDivCost}, 1204 { ISD::UDIV, MVT::v8i16, 8 * FunctionCallDivCost}, 1205 { ISD::SREM, MVT::v8i16, 8 * FunctionCallDivCost}, 1206 { ISD::UREM, MVT::v8i16, 8 * FunctionCallDivCost}, 1207 { ISD::SDIV, MVT::v16i8, 16 * FunctionCallDivCost}, 1208 { ISD::UDIV, MVT::v16i8, 16 * FunctionCallDivCost}, 1209 { ISD::SREM, MVT::v16i8, 16 * FunctionCallDivCost}, 1210 { ISD::UREM, MVT::v16i8, 16 * FunctionCallDivCost}, 1211 // Multiplication. 1212 }; 1213 1214 if (const auto *Entry = CostTableLookup(CostTbl, ISDOpcode, LT.second)) 1215 return LT.first * Entry->Cost; 1216 1217 int Cost = BaseT::getArithmeticInstrCost(Opcode, Ty, CostKind, Op1Info, 1218 Op2Info, 1219 Opd1PropInfo, Opd2PropInfo); 1220 1221 // This is somewhat of a hack. The problem that we are facing is that SROA 1222 // creates a sequence of shift, and, or instructions to construct values. 1223 // These sequences are recognized by the ISel and have zero-cost. Not so for 1224 // the vectorized code. Because we have support for v2i64 but not i64 those 1225 // sequences look particularly beneficial to vectorize. 1226 // To work around this we increase the cost of v2i64 operations to make them 1227 // seem less beneficial. 1228 if (LT.second == MVT::v2i64 && 1229 Op2Info == TargetTransformInfo::OK_UniformConstantValue) 1230 Cost += 4; 1231 1232 return Cost; 1233 } 1234 1235 // If this operation is a shift on arm/thumb2, it might well be folded into 1236 // the following instruction, hence having a cost of 0. 1237 auto LooksLikeAFreeShift = [&]() { 1238 if (ST->isThumb1Only() || Ty->isVectorTy()) 1239 return false; 1240 1241 if (!CxtI || !CxtI->hasOneUse() || !CxtI->isShift()) 1242 return false; 1243 if (Op2Info != TargetTransformInfo::OK_UniformConstantValue) 1244 return false; 1245 1246 // Folded into a ADC/ADD/AND/BIC/CMP/EOR/MVN/ORR/ORN/RSB/SBC/SUB 1247 switch (cast<Instruction>(CxtI->user_back())->getOpcode()) { 1248 case Instruction::Add: 1249 case Instruction::Sub: 1250 case Instruction::And: 1251 case Instruction::Xor: 1252 case Instruction::Or: 1253 case Instruction::ICmp: 1254 return true; 1255 default: 1256 return false; 1257 } 1258 }; 1259 if (LooksLikeAFreeShift()) 1260 return 0; 1261 1262 // Default to cheap (throughput/size of 1 instruction) but adjust throughput 1263 // for "multiple beats" potentially needed by MVE instructions. 1264 int BaseCost = 1; 1265 if (CostKind != TTI::TCK_CodeSize && ST->hasMVEIntegerOps() && 1266 Ty->isVectorTy()) 1267 BaseCost = ST->getMVEVectorCostFactor(); 1268 1269 // The rest of this mostly follows what is done in BaseT::getArithmeticInstrCost, 1270 // without treating floats as more expensive that scalars or increasing the 1271 // costs for custom operations. The results is also multiplied by the 1272 // MVEVectorCostFactor where appropriate. 1273 if (TLI->isOperationLegalOrCustomOrPromote(ISDOpcode, LT.second)) 1274 return LT.first * BaseCost; 1275 1276 // Else this is expand, assume that we need to scalarize this op. 1277 if (auto *VTy = dyn_cast<FixedVectorType>(Ty)) { 1278 unsigned Num = VTy->getNumElements(); 1279 unsigned Cost = getArithmeticInstrCost(Opcode, Ty->getScalarType(), 1280 CostKind); 1281 // Return the cost of multiple scalar invocation plus the cost of 1282 // inserting and extracting the values. 1283 return BaseT::getScalarizationOverhead(VTy, Args) + Num * Cost; 1284 } 1285 1286 return BaseCost; 1287 } 1288 1289 int ARMTTIImpl::getMemoryOpCost(unsigned Opcode, Type *Src, 1290 MaybeAlign Alignment, unsigned AddressSpace, 1291 TTI::TargetCostKind CostKind, 1292 const Instruction *I) { 1293 // TODO: Handle other cost kinds. 1294 if (CostKind != TTI::TCK_RecipThroughput) 1295 return 1; 1296 1297 // Type legalization can't handle structs 1298 if (TLI->getValueType(DL, Src, true) == MVT::Other) 1299 return BaseT::getMemoryOpCost(Opcode, Src, Alignment, AddressSpace, 1300 CostKind); 1301 1302 if (ST->hasNEON() && Src->isVectorTy() && 1303 (Alignment && *Alignment != Align(16)) && 1304 cast<VectorType>(Src)->getElementType()->isDoubleTy()) { 1305 // Unaligned loads/stores are extremely inefficient. 1306 // We need 4 uops for vst.1/vld.1 vs 1uop for vldr/vstr. 1307 std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, Src); 1308 return LT.first * 4; 1309 } 1310 1311 // MVE can optimize a fpext(load(4xhalf)) using an extending integer load. 1312 // Same for stores. 1313 if (ST->hasMVEFloatOps() && isa<FixedVectorType>(Src) && I && 1314 ((Opcode == Instruction::Load && I->hasOneUse() && 1315 isa<FPExtInst>(*I->user_begin())) || 1316 (Opcode == Instruction::Store && isa<FPTruncInst>(I->getOperand(0))))) { 1317 FixedVectorType *SrcVTy = cast<FixedVectorType>(Src); 1318 Type *DstTy = 1319 Opcode == Instruction::Load 1320 ? (*I->user_begin())->getType() 1321 : cast<Instruction>(I->getOperand(0))->getOperand(0)->getType(); 1322 if (SrcVTy->getNumElements() == 4 && SrcVTy->getScalarType()->isHalfTy() && 1323 DstTy->getScalarType()->isFloatTy()) 1324 return ST->getMVEVectorCostFactor(); 1325 } 1326 1327 int BaseCost = ST->hasMVEIntegerOps() && Src->isVectorTy() 1328 ? ST->getMVEVectorCostFactor() 1329 : 1; 1330 return BaseCost * BaseT::getMemoryOpCost(Opcode, Src, Alignment, AddressSpace, 1331 CostKind, I); 1332 } 1333 1334 unsigned ARMTTIImpl::getMaskedMemoryOpCost(unsigned Opcode, Type *Src, 1335 Align Alignment, 1336 unsigned AddressSpace, 1337 TTI::TargetCostKind CostKind) { 1338 if (ST->hasMVEIntegerOps()) { 1339 if (Opcode == Instruction::Load && isLegalMaskedLoad(Src, Alignment)) 1340 return ST->getMVEVectorCostFactor(); 1341 if (Opcode == Instruction::Store && isLegalMaskedStore(Src, Alignment)) 1342 return ST->getMVEVectorCostFactor(); 1343 } 1344 if (!isa<FixedVectorType>(Src)) 1345 return BaseT::getMaskedMemoryOpCost(Opcode, Src, Alignment, AddressSpace, 1346 CostKind); 1347 // Scalar cost, which is currently very high due to the efficiency of the 1348 // generated code. 1349 return cast<FixedVectorType>(Src)->getNumElements() * 8; 1350 } 1351 1352 int ARMTTIImpl::getInterleavedMemoryOpCost( 1353 unsigned Opcode, Type *VecTy, unsigned Factor, ArrayRef<unsigned> Indices, 1354 Align Alignment, unsigned AddressSpace, TTI::TargetCostKind CostKind, 1355 bool UseMaskForCond, bool UseMaskForGaps) { 1356 assert(Factor >= 2 && "Invalid interleave factor"); 1357 assert(isa<VectorType>(VecTy) && "Expect a vector type"); 1358 1359 // vldN/vstN doesn't support vector types of i64/f64 element. 1360 bool EltIs64Bits = DL.getTypeSizeInBits(VecTy->getScalarType()) == 64; 1361 1362 if (Factor <= TLI->getMaxSupportedInterleaveFactor() && !EltIs64Bits && 1363 !UseMaskForCond && !UseMaskForGaps) { 1364 unsigned NumElts = cast<FixedVectorType>(VecTy)->getNumElements(); 1365 auto *SubVecTy = 1366 FixedVectorType::get(VecTy->getScalarType(), NumElts / Factor); 1367 1368 // vldN/vstN only support legal vector types of size 64 or 128 in bits. 1369 // Accesses having vector types that are a multiple of 128 bits can be 1370 // matched to more than one vldN/vstN instruction. 1371 int BaseCost = ST->hasMVEIntegerOps() ? ST->getMVEVectorCostFactor() : 1; 1372 if (NumElts % Factor == 0 && 1373 TLI->isLegalInterleavedAccessType(Factor, SubVecTy, DL)) 1374 return Factor * BaseCost * TLI->getNumInterleavedAccesses(SubVecTy, DL); 1375 1376 // Some smaller than legal interleaved patterns are cheap as we can make 1377 // use of the vmovn or vrev patterns to interleave a standard load. This is 1378 // true for v4i8, v8i8 and v4i16 at least (but not for v4f16 as it is 1379 // promoted differently). The cost of 2 here is then a load and vrev or 1380 // vmovn. 1381 if (ST->hasMVEIntegerOps() && Factor == 2 && NumElts / Factor > 2 && 1382 VecTy->isIntOrIntVectorTy() && 1383 DL.getTypeSizeInBits(SubVecTy).getFixedSize() <= 64) 1384 return 2 * BaseCost; 1385 } 1386 1387 return BaseT::getInterleavedMemoryOpCost(Opcode, VecTy, Factor, Indices, 1388 Alignment, AddressSpace, CostKind, 1389 UseMaskForCond, UseMaskForGaps); 1390 } 1391 1392 unsigned ARMTTIImpl::getGatherScatterOpCost(unsigned Opcode, Type *DataTy, 1393 const Value *Ptr, bool VariableMask, 1394 Align Alignment, 1395 TTI::TargetCostKind CostKind, 1396 const Instruction *I) { 1397 using namespace PatternMatch; 1398 if (!ST->hasMVEIntegerOps() || !EnableMaskedGatherScatters) 1399 return BaseT::getGatherScatterOpCost(Opcode, DataTy, Ptr, VariableMask, 1400 Alignment, CostKind, I); 1401 1402 assert(DataTy->isVectorTy() && "Can't do gather/scatters on scalar!"); 1403 auto *VTy = cast<FixedVectorType>(DataTy); 1404 1405 // TODO: Splitting, once we do that. 1406 1407 unsigned NumElems = VTy->getNumElements(); 1408 unsigned EltSize = VTy->getScalarSizeInBits(); 1409 std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, DataTy); 1410 1411 // For now, it is assumed that for the MVE gather instructions the loads are 1412 // all effectively serialised. This means the cost is the scalar cost 1413 // multiplied by the number of elements being loaded. This is possibly very 1414 // conservative, but even so we still end up vectorising loops because the 1415 // cost per iteration for many loops is lower than for scalar loops. 1416 unsigned VectorCost = NumElems * LT.first * ST->getMVEVectorCostFactor(); 1417 // The scalarization cost should be a lot higher. We use the number of vector 1418 // elements plus the scalarization overhead. 1419 unsigned ScalarCost = 1420 NumElems * LT.first + BaseT::getScalarizationOverhead(VTy, {}); 1421 1422 if (EltSize < 8 || Alignment < EltSize / 8) 1423 return ScalarCost; 1424 1425 unsigned ExtSize = EltSize; 1426 // Check whether there's a single user that asks for an extended type 1427 if (I != nullptr) { 1428 // Dependent of the caller of this function, a gather instruction will 1429 // either have opcode Instruction::Load or be a call to the masked_gather 1430 // intrinsic 1431 if ((I->getOpcode() == Instruction::Load || 1432 match(I, m_Intrinsic<Intrinsic::masked_gather>())) && 1433 I->hasOneUse()) { 1434 const User *Us = *I->users().begin(); 1435 if (isa<ZExtInst>(Us) || isa<SExtInst>(Us)) { 1436 // only allow valid type combinations 1437 unsigned TypeSize = 1438 cast<Instruction>(Us)->getType()->getScalarSizeInBits(); 1439 if (((TypeSize == 32 && (EltSize == 8 || EltSize == 16)) || 1440 (TypeSize == 16 && EltSize == 8)) && 1441 TypeSize * NumElems == 128) { 1442 ExtSize = TypeSize; 1443 } 1444 } 1445 } 1446 // Check whether the input data needs to be truncated 1447 TruncInst *T; 1448 if ((I->getOpcode() == Instruction::Store || 1449 match(I, m_Intrinsic<Intrinsic::masked_scatter>())) && 1450 (T = dyn_cast<TruncInst>(I->getOperand(0)))) { 1451 // Only allow valid type combinations 1452 unsigned TypeSize = T->getOperand(0)->getType()->getScalarSizeInBits(); 1453 if (((EltSize == 16 && TypeSize == 32) || 1454 (EltSize == 8 && (TypeSize == 32 || TypeSize == 16))) && 1455 TypeSize * NumElems == 128) 1456 ExtSize = TypeSize; 1457 } 1458 } 1459 1460 if (ExtSize * NumElems != 128 || NumElems < 4) 1461 return ScalarCost; 1462 1463 // Any (aligned) i32 gather will not need to be scalarised. 1464 if (ExtSize == 32) 1465 return VectorCost; 1466 // For smaller types, we need to ensure that the gep's inputs are correctly 1467 // extended from a small enough value. Other sizes (including i64) are 1468 // scalarized for now. 1469 if (ExtSize != 8 && ExtSize != 16) 1470 return ScalarCost; 1471 1472 if (const auto *BC = dyn_cast<BitCastInst>(Ptr)) 1473 Ptr = BC->getOperand(0); 1474 if (const auto *GEP = dyn_cast<GetElementPtrInst>(Ptr)) { 1475 if (GEP->getNumOperands() != 2) 1476 return ScalarCost; 1477 unsigned Scale = DL.getTypeAllocSize(GEP->getResultElementType()); 1478 // Scale needs to be correct (which is only relevant for i16s). 1479 if (Scale != 1 && Scale * 8 != ExtSize) 1480 return ScalarCost; 1481 // And we need to zext (not sext) the indexes from a small enough type. 1482 if (const auto *ZExt = dyn_cast<ZExtInst>(GEP->getOperand(1))) { 1483 if (ZExt->getOperand(0)->getType()->getScalarSizeInBits() <= ExtSize) 1484 return VectorCost; 1485 } 1486 return ScalarCost; 1487 } 1488 return ScalarCost; 1489 } 1490 1491 int ARMTTIImpl::getArithmeticReductionCost(unsigned Opcode, VectorType *ValTy, 1492 bool IsPairwiseForm, 1493 TTI::TargetCostKind CostKind) { 1494 EVT ValVT = TLI->getValueType(DL, ValTy); 1495 int ISD = TLI->InstructionOpcodeToISD(Opcode); 1496 if (!ST->hasMVEIntegerOps() || !ValVT.isSimple() || ISD != ISD::ADD) 1497 return BaseT::getArithmeticReductionCost(Opcode, ValTy, IsPairwiseForm, 1498 CostKind); 1499 1500 std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, ValTy); 1501 1502 static const CostTblEntry CostTblAdd[]{ 1503 {ISD::ADD, MVT::v16i8, 1}, 1504 {ISD::ADD, MVT::v8i16, 1}, 1505 {ISD::ADD, MVT::v4i32, 1}, 1506 }; 1507 if (const auto *Entry = CostTableLookup(CostTblAdd, ISD, LT.second)) 1508 return Entry->Cost * ST->getMVEVectorCostFactor() * LT.first; 1509 1510 return BaseT::getArithmeticReductionCost(Opcode, ValTy, IsPairwiseForm, 1511 CostKind); 1512 } 1513 1514 InstructionCost 1515 ARMTTIImpl::getExtendedAddReductionCost(bool IsMLA, bool IsUnsigned, 1516 Type *ResTy, VectorType *ValTy, 1517 TTI::TargetCostKind CostKind) { 1518 EVT ValVT = TLI->getValueType(DL, ValTy); 1519 EVT ResVT = TLI->getValueType(DL, ResTy); 1520 if (ST->hasMVEIntegerOps() && ValVT.isSimple() && ResVT.isSimple()) { 1521 std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, ValTy); 1522 if ((LT.second == MVT::v16i8 && ResVT.getSizeInBits() <= 32) || 1523 (LT.second == MVT::v8i16 && 1524 ResVT.getSizeInBits() <= (IsMLA ? 64 : 32)) || 1525 (LT.second == MVT::v4i32 && ResVT.getSizeInBits() <= 64)) 1526 return ST->getMVEVectorCostFactor() * LT.first; 1527 } 1528 1529 return BaseT::getExtendedAddReductionCost(IsMLA, IsUnsigned, ResTy, ValTy, 1530 CostKind); 1531 } 1532 1533 int ARMTTIImpl::getIntrinsicInstrCost(const IntrinsicCostAttributes &ICA, 1534 TTI::TargetCostKind CostKind) { 1535 switch (ICA.getID()) { 1536 case Intrinsic::get_active_lane_mask: 1537 // Currently we make a somewhat optimistic assumption that 1538 // active_lane_mask's are always free. In reality it may be freely folded 1539 // into a tail predicated loop, expanded into a VCPT or expanded into a lot 1540 // of add/icmp code. We may need to improve this in the future, but being 1541 // able to detect if it is free or not involves looking at a lot of other 1542 // code. We currently assume that the vectorizer inserted these, and knew 1543 // what it was doing in adding one. 1544 if (ST->hasMVEIntegerOps()) 1545 return 0; 1546 break; 1547 case Intrinsic::sadd_sat: 1548 case Intrinsic::ssub_sat: 1549 case Intrinsic::uadd_sat: 1550 case Intrinsic::usub_sat: { 1551 if (!ST->hasMVEIntegerOps()) 1552 break; 1553 // Get the Return type, either directly of from ICA.ReturnType and ICA.VF. 1554 Type *VT = ICA.getReturnType(); 1555 if (!VT->isVectorTy() && !ICA.getVectorFactor().isScalar()) 1556 VT = VectorType::get(VT, ICA.getVectorFactor()); 1557 1558 std::pair<int, MVT> LT = 1559 TLI->getTypeLegalizationCost(DL, VT); 1560 if (LT.second == MVT::v4i32 || LT.second == MVT::v8i16 || 1561 LT.second == MVT::v16i8) { 1562 // This is a base cost of 1 for the vadd, plus 3 extract shifts if we 1563 // need to extend the type, as it uses shr(qadd(shl, shl)). 1564 unsigned Instrs = LT.second.getScalarSizeInBits() == 1565 ICA.getReturnType()->getScalarSizeInBits() 1566 ? 1 1567 : 4; 1568 return LT.first * ST->getMVEVectorCostFactor() * Instrs; 1569 } 1570 break; 1571 } 1572 } 1573 1574 return BaseT::getIntrinsicInstrCost(ICA, CostKind); 1575 } 1576 1577 bool ARMTTIImpl::isLoweredToCall(const Function *F) { 1578 if (!F->isIntrinsic()) 1579 BaseT::isLoweredToCall(F); 1580 1581 // Assume all Arm-specific intrinsics map to an instruction. 1582 if (F->getName().startswith("llvm.arm")) 1583 return false; 1584 1585 switch (F->getIntrinsicID()) { 1586 default: break; 1587 case Intrinsic::powi: 1588 case Intrinsic::sin: 1589 case Intrinsic::cos: 1590 case Intrinsic::pow: 1591 case Intrinsic::log: 1592 case Intrinsic::log10: 1593 case Intrinsic::log2: 1594 case Intrinsic::exp: 1595 case Intrinsic::exp2: 1596 return true; 1597 case Intrinsic::sqrt: 1598 case Intrinsic::fabs: 1599 case Intrinsic::copysign: 1600 case Intrinsic::floor: 1601 case Intrinsic::ceil: 1602 case Intrinsic::trunc: 1603 case Intrinsic::rint: 1604 case Intrinsic::nearbyint: 1605 case Intrinsic::round: 1606 case Intrinsic::canonicalize: 1607 case Intrinsic::lround: 1608 case Intrinsic::llround: 1609 case Intrinsic::lrint: 1610 case Intrinsic::llrint: 1611 if (F->getReturnType()->isDoubleTy() && !ST->hasFP64()) 1612 return true; 1613 if (F->getReturnType()->isHalfTy() && !ST->hasFullFP16()) 1614 return true; 1615 // Some operations can be handled by vector instructions and assume 1616 // unsupported vectors will be expanded into supported scalar ones. 1617 // TODO Handle scalar operations properly. 1618 return !ST->hasFPARMv8Base() && !ST->hasVFP2Base(); 1619 case Intrinsic::masked_store: 1620 case Intrinsic::masked_load: 1621 case Intrinsic::masked_gather: 1622 case Intrinsic::masked_scatter: 1623 return !ST->hasMVEIntegerOps(); 1624 case Intrinsic::sadd_with_overflow: 1625 case Intrinsic::uadd_with_overflow: 1626 case Intrinsic::ssub_with_overflow: 1627 case Intrinsic::usub_with_overflow: 1628 case Intrinsic::sadd_sat: 1629 case Intrinsic::uadd_sat: 1630 case Intrinsic::ssub_sat: 1631 case Intrinsic::usub_sat: 1632 return false; 1633 } 1634 1635 return BaseT::isLoweredToCall(F); 1636 } 1637 1638 bool ARMTTIImpl::maybeLoweredToCall(Instruction &I) { 1639 unsigned ISD = TLI->InstructionOpcodeToISD(I.getOpcode()); 1640 EVT VT = TLI->getValueType(DL, I.getType(), true); 1641 if (TLI->getOperationAction(ISD, VT) == TargetLowering::LibCall) 1642 return true; 1643 1644 // Check if an intrinsic will be lowered to a call and assume that any 1645 // other CallInst will generate a bl. 1646 if (auto *Call = dyn_cast<CallInst>(&I)) { 1647 if (auto *II = dyn_cast<IntrinsicInst>(Call)) { 1648 switch(II->getIntrinsicID()) { 1649 case Intrinsic::memcpy: 1650 case Intrinsic::memset: 1651 case Intrinsic::memmove: 1652 return getNumMemOps(II) == -1; 1653 default: 1654 if (const Function *F = Call->getCalledFunction()) 1655 return isLoweredToCall(F); 1656 } 1657 } 1658 return true; 1659 } 1660 1661 // FPv5 provides conversions between integer, double-precision, 1662 // single-precision, and half-precision formats. 1663 switch (I.getOpcode()) { 1664 default: 1665 break; 1666 case Instruction::FPToSI: 1667 case Instruction::FPToUI: 1668 case Instruction::SIToFP: 1669 case Instruction::UIToFP: 1670 case Instruction::FPTrunc: 1671 case Instruction::FPExt: 1672 return !ST->hasFPARMv8Base(); 1673 } 1674 1675 // FIXME: Unfortunately the approach of checking the Operation Action does 1676 // not catch all cases of Legalization that use library calls. Our 1677 // Legalization step categorizes some transformations into library calls as 1678 // Custom, Expand or even Legal when doing type legalization. So for now 1679 // we have to special case for instance the SDIV of 64bit integers and the 1680 // use of floating point emulation. 1681 if (VT.isInteger() && VT.getSizeInBits() >= 64) { 1682 switch (ISD) { 1683 default: 1684 break; 1685 case ISD::SDIV: 1686 case ISD::UDIV: 1687 case ISD::SREM: 1688 case ISD::UREM: 1689 case ISD::SDIVREM: 1690 case ISD::UDIVREM: 1691 return true; 1692 } 1693 } 1694 1695 // Assume all other non-float operations are supported. 1696 if (!VT.isFloatingPoint()) 1697 return false; 1698 1699 // We'll need a library call to handle most floats when using soft. 1700 if (TLI->useSoftFloat()) { 1701 switch (I.getOpcode()) { 1702 default: 1703 return true; 1704 case Instruction::Alloca: 1705 case Instruction::Load: 1706 case Instruction::Store: 1707 case Instruction::Select: 1708 case Instruction::PHI: 1709 return false; 1710 } 1711 } 1712 1713 // We'll need a libcall to perform double precision operations on a single 1714 // precision only FPU. 1715 if (I.getType()->isDoubleTy() && !ST->hasFP64()) 1716 return true; 1717 1718 // Likewise for half precision arithmetic. 1719 if (I.getType()->isHalfTy() && !ST->hasFullFP16()) 1720 return true; 1721 1722 return false; 1723 } 1724 1725 bool ARMTTIImpl::isHardwareLoopProfitable(Loop *L, ScalarEvolution &SE, 1726 AssumptionCache &AC, 1727 TargetLibraryInfo *LibInfo, 1728 HardwareLoopInfo &HWLoopInfo) { 1729 // Low-overhead branches are only supported in the 'low-overhead branch' 1730 // extension of v8.1-m. 1731 if (!ST->hasLOB() || DisableLowOverheadLoops) { 1732 LLVM_DEBUG(dbgs() << "ARMHWLoops: Disabled\n"); 1733 return false; 1734 } 1735 1736 if (!SE.hasLoopInvariantBackedgeTakenCount(L)) { 1737 LLVM_DEBUG(dbgs() << "ARMHWLoops: No BETC\n"); 1738 return false; 1739 } 1740 1741 const SCEV *BackedgeTakenCount = SE.getBackedgeTakenCount(L); 1742 if (isa<SCEVCouldNotCompute>(BackedgeTakenCount)) { 1743 LLVM_DEBUG(dbgs() << "ARMHWLoops: Uncomputable BETC\n"); 1744 return false; 1745 } 1746 1747 const SCEV *TripCountSCEV = 1748 SE.getAddExpr(BackedgeTakenCount, 1749 SE.getOne(BackedgeTakenCount->getType())); 1750 1751 // We need to store the trip count in LR, a 32-bit register. 1752 if (SE.getUnsignedRangeMax(TripCountSCEV).getBitWidth() > 32) { 1753 LLVM_DEBUG(dbgs() << "ARMHWLoops: Trip count does not fit into 32bits\n"); 1754 return false; 1755 } 1756 1757 // Making a call will trash LR and clear LO_BRANCH_INFO, so there's little 1758 // point in generating a hardware loop if that's going to happen. 1759 1760 auto IsHardwareLoopIntrinsic = [](Instruction &I) { 1761 if (auto *Call = dyn_cast<IntrinsicInst>(&I)) { 1762 switch (Call->getIntrinsicID()) { 1763 default: 1764 break; 1765 case Intrinsic::start_loop_iterations: 1766 case Intrinsic::test_set_loop_iterations: 1767 case Intrinsic::loop_decrement: 1768 case Intrinsic::loop_decrement_reg: 1769 return true; 1770 } 1771 } 1772 return false; 1773 }; 1774 1775 // Scan the instructions to see if there's any that we know will turn into a 1776 // call or if this loop is already a low-overhead loop or will become a tail 1777 // predicated loop. 1778 bool IsTailPredLoop = false; 1779 auto ScanLoop = [&](Loop *L) { 1780 for (auto *BB : L->getBlocks()) { 1781 for (auto &I : *BB) { 1782 if (maybeLoweredToCall(I) || IsHardwareLoopIntrinsic(I) || 1783 isa<InlineAsm>(I)) { 1784 LLVM_DEBUG(dbgs() << "ARMHWLoops: Bad instruction: " << I << "\n"); 1785 return false; 1786 } 1787 if (auto *II = dyn_cast<IntrinsicInst>(&I)) 1788 IsTailPredLoop |= 1789 II->getIntrinsicID() == Intrinsic::get_active_lane_mask || 1790 II->getIntrinsicID() == Intrinsic::arm_mve_vctp8 || 1791 II->getIntrinsicID() == Intrinsic::arm_mve_vctp16 || 1792 II->getIntrinsicID() == Intrinsic::arm_mve_vctp32 || 1793 II->getIntrinsicID() == Intrinsic::arm_mve_vctp64; 1794 } 1795 } 1796 return true; 1797 }; 1798 1799 // Visit inner loops. 1800 for (auto Inner : *L) 1801 if (!ScanLoop(Inner)) 1802 return false; 1803 1804 if (!ScanLoop(L)) 1805 return false; 1806 1807 // TODO: Check whether the trip count calculation is expensive. If L is the 1808 // inner loop but we know it has a low trip count, calculating that trip 1809 // count (in the parent loop) may be detrimental. 1810 1811 LLVMContext &C = L->getHeader()->getContext(); 1812 HWLoopInfo.CounterInReg = true; 1813 HWLoopInfo.IsNestingLegal = false; 1814 HWLoopInfo.PerformEntryTest = AllowWLSLoops && !IsTailPredLoop; 1815 HWLoopInfo.CountType = Type::getInt32Ty(C); 1816 HWLoopInfo.LoopDecrement = ConstantInt::get(HWLoopInfo.CountType, 1); 1817 return true; 1818 } 1819 1820 static bool canTailPredicateInstruction(Instruction &I, int &ICmpCount) { 1821 // We don't allow icmp's, and because we only look at single block loops, 1822 // we simply count the icmps, i.e. there should only be 1 for the backedge. 1823 if (isa<ICmpInst>(&I) && ++ICmpCount > 1) 1824 return false; 1825 1826 if (isa<FCmpInst>(&I)) 1827 return false; 1828 1829 // We could allow extending/narrowing FP loads/stores, but codegen is 1830 // too inefficient so reject this for now. 1831 if (isa<FPExtInst>(&I) || isa<FPTruncInst>(&I)) 1832 return false; 1833 1834 // Extends have to be extending-loads 1835 if (isa<SExtInst>(&I) || isa<ZExtInst>(&I) ) 1836 if (!I.getOperand(0)->hasOneUse() || !isa<LoadInst>(I.getOperand(0))) 1837 return false; 1838 1839 // Truncs have to be narrowing-stores 1840 if (isa<TruncInst>(&I) ) 1841 if (!I.hasOneUse() || !isa<StoreInst>(*I.user_begin())) 1842 return false; 1843 1844 return true; 1845 } 1846 1847 // To set up a tail-predicated loop, we need to know the total number of 1848 // elements processed by that loop. Thus, we need to determine the element 1849 // size and: 1850 // 1) it should be uniform for all operations in the vector loop, so we 1851 // e.g. don't want any widening/narrowing operations. 1852 // 2) it should be smaller than i64s because we don't have vector operations 1853 // that work on i64s. 1854 // 3) we don't want elements to be reversed or shuffled, to make sure the 1855 // tail-predication masks/predicates the right lanes. 1856 // 1857 static bool canTailPredicateLoop(Loop *L, LoopInfo *LI, ScalarEvolution &SE, 1858 const DataLayout &DL, 1859 const LoopAccessInfo *LAI) { 1860 LLVM_DEBUG(dbgs() << "Tail-predication: checking allowed instructions\n"); 1861 1862 // If there are live-out values, it is probably a reduction. We can predicate 1863 // most reduction operations freely under MVE using a combination of 1864 // prefer-predicated-reduction-select and inloop reductions. We limit this to 1865 // floating point and integer reductions, but don't check for operators 1866 // specifically here. If the value ends up not being a reduction (and so the 1867 // vectorizer cannot tailfold the loop), we should fall back to standard 1868 // vectorization automatically. 1869 SmallVector< Instruction *, 8 > LiveOuts; 1870 LiveOuts = llvm::findDefsUsedOutsideOfLoop(L); 1871 bool ReductionsDisabled = 1872 EnableTailPredication == TailPredication::EnabledNoReductions || 1873 EnableTailPredication == TailPredication::ForceEnabledNoReductions; 1874 1875 for (auto *I : LiveOuts) { 1876 if (!I->getType()->isIntegerTy() && !I->getType()->isFloatTy() && 1877 !I->getType()->isHalfTy()) { 1878 LLVM_DEBUG(dbgs() << "Don't tail-predicate loop with non-integer/float " 1879 "live-out value\n"); 1880 return false; 1881 } 1882 if (ReductionsDisabled) { 1883 LLVM_DEBUG(dbgs() << "Reductions not enabled\n"); 1884 return false; 1885 } 1886 } 1887 1888 // Next, check that all instructions can be tail-predicated. 1889 PredicatedScalarEvolution PSE = LAI->getPSE(); 1890 SmallVector<Instruction *, 16> LoadStores; 1891 int ICmpCount = 0; 1892 1893 for (BasicBlock *BB : L->blocks()) { 1894 for (Instruction &I : BB->instructionsWithoutDebug()) { 1895 if (isa<PHINode>(&I)) 1896 continue; 1897 if (!canTailPredicateInstruction(I, ICmpCount)) { 1898 LLVM_DEBUG(dbgs() << "Instruction not allowed: "; I.dump()); 1899 return false; 1900 } 1901 1902 Type *T = I.getType(); 1903 if (T->isPointerTy()) 1904 T = T->getPointerElementType(); 1905 1906 if (T->getScalarSizeInBits() > 32) { 1907 LLVM_DEBUG(dbgs() << "Unsupported Type: "; T->dump()); 1908 return false; 1909 } 1910 if (isa<StoreInst>(I) || isa<LoadInst>(I)) { 1911 Value *Ptr = isa<LoadInst>(I) ? I.getOperand(0) : I.getOperand(1); 1912 int64_t NextStride = getPtrStride(PSE, Ptr, L); 1913 if (NextStride == 1) { 1914 // TODO: for now only allow consecutive strides of 1. We could support 1915 // other strides as long as it is uniform, but let's keep it simple 1916 // for now. 1917 continue; 1918 } else if (NextStride == -1 || 1919 (NextStride == 2 && MVEMaxSupportedInterleaveFactor >= 2) || 1920 (NextStride == 4 && MVEMaxSupportedInterleaveFactor >= 4)) { 1921 LLVM_DEBUG(dbgs() 1922 << "Consecutive strides of 2 found, vld2/vstr2 can't " 1923 "be tail-predicated\n."); 1924 return false; 1925 // TODO: don't tail predicate if there is a reversed load? 1926 } else if (EnableMaskedGatherScatters) { 1927 // Gather/scatters do allow loading from arbitrary strides, at 1928 // least if they are loop invariant. 1929 // TODO: Loop variant strides should in theory work, too, but 1930 // this requires further testing. 1931 const SCEV *PtrScev = 1932 replaceSymbolicStrideSCEV(PSE, llvm::ValueToValueMap(), Ptr); 1933 if (auto AR = dyn_cast<SCEVAddRecExpr>(PtrScev)) { 1934 const SCEV *Step = AR->getStepRecurrence(*PSE.getSE()); 1935 if (PSE.getSE()->isLoopInvariant(Step, L)) 1936 continue; 1937 } 1938 } 1939 LLVM_DEBUG(dbgs() << "Bad stride found, can't " 1940 "tail-predicate\n."); 1941 return false; 1942 } 1943 } 1944 } 1945 1946 LLVM_DEBUG(dbgs() << "tail-predication: all instructions allowed!\n"); 1947 return true; 1948 } 1949 1950 bool ARMTTIImpl::preferPredicateOverEpilogue(Loop *L, LoopInfo *LI, 1951 ScalarEvolution &SE, 1952 AssumptionCache &AC, 1953 TargetLibraryInfo *TLI, 1954 DominatorTree *DT, 1955 const LoopAccessInfo *LAI) { 1956 if (!EnableTailPredication) { 1957 LLVM_DEBUG(dbgs() << "Tail-predication not enabled.\n"); 1958 return false; 1959 } 1960 1961 // Creating a predicated vector loop is the first step for generating a 1962 // tail-predicated hardware loop, for which we need the MVE masked 1963 // load/stores instructions: 1964 if (!ST->hasMVEIntegerOps()) 1965 return false; 1966 1967 // For now, restrict this to single block loops. 1968 if (L->getNumBlocks() > 1) { 1969 LLVM_DEBUG(dbgs() << "preferPredicateOverEpilogue: not a single block " 1970 "loop.\n"); 1971 return false; 1972 } 1973 1974 assert(L->isInnermost() && "preferPredicateOverEpilogue: inner-loop expected"); 1975 1976 HardwareLoopInfo HWLoopInfo(L); 1977 if (!HWLoopInfo.canAnalyze(*LI)) { 1978 LLVM_DEBUG(dbgs() << "preferPredicateOverEpilogue: hardware-loop is not " 1979 "analyzable.\n"); 1980 return false; 1981 } 1982 1983 // This checks if we have the low-overhead branch architecture 1984 // extension, and if we will create a hardware-loop: 1985 if (!isHardwareLoopProfitable(L, SE, AC, TLI, HWLoopInfo)) { 1986 LLVM_DEBUG(dbgs() << "preferPredicateOverEpilogue: hardware-loop is not " 1987 "profitable.\n"); 1988 return false; 1989 } 1990 1991 if (!HWLoopInfo.isHardwareLoopCandidate(SE, *LI, *DT)) { 1992 LLVM_DEBUG(dbgs() << "preferPredicateOverEpilogue: hardware-loop is not " 1993 "a candidate.\n"); 1994 return false; 1995 } 1996 1997 return canTailPredicateLoop(L, LI, SE, DL, LAI); 1998 } 1999 2000 bool ARMTTIImpl::emitGetActiveLaneMask() const { 2001 if (!ST->hasMVEIntegerOps() || !EnableTailPredication) 2002 return false; 2003 2004 // Intrinsic @llvm.get.active.lane.mask is supported. 2005 // It is used in the MVETailPredication pass, which requires the number of 2006 // elements processed by this vector loop to setup the tail-predicated 2007 // loop. 2008 return true; 2009 } 2010 void ARMTTIImpl::getUnrollingPreferences(Loop *L, ScalarEvolution &SE, 2011 TTI::UnrollingPreferences &UP) { 2012 // Only currently enable these preferences for M-Class cores. 2013 if (!ST->isMClass()) 2014 return BasicTTIImplBase::getUnrollingPreferences(L, SE, UP); 2015 2016 // Disable loop unrolling for Oz and Os. 2017 UP.OptSizeThreshold = 0; 2018 UP.PartialOptSizeThreshold = 0; 2019 if (L->getHeader()->getParent()->hasOptSize()) 2020 return; 2021 2022 // Only enable on Thumb-2 targets. 2023 if (!ST->isThumb2()) 2024 return; 2025 2026 SmallVector<BasicBlock*, 4> ExitingBlocks; 2027 L->getExitingBlocks(ExitingBlocks); 2028 LLVM_DEBUG(dbgs() << "Loop has:\n" 2029 << "Blocks: " << L->getNumBlocks() << "\n" 2030 << "Exit blocks: " << ExitingBlocks.size() << "\n"); 2031 2032 // Only allow another exit other than the latch. This acts as an early exit 2033 // as it mirrors the profitability calculation of the runtime unroller. 2034 if (ExitingBlocks.size() > 2) 2035 return; 2036 2037 // Limit the CFG of the loop body for targets with a branch predictor. 2038 // Allowing 4 blocks permits if-then-else diamonds in the body. 2039 if (ST->hasBranchPredictor() && L->getNumBlocks() > 4) 2040 return; 2041 2042 // Don't unroll vectorized loops, including the remainder loop 2043 if (getBooleanLoopAttribute(L, "llvm.loop.isvectorized")) 2044 return; 2045 2046 // Scan the loop: don't unroll loops with calls as this could prevent 2047 // inlining. 2048 unsigned Cost = 0; 2049 for (auto *BB : L->getBlocks()) { 2050 for (auto &I : *BB) { 2051 // Don't unroll vectorised loop. MVE does not benefit from it as much as 2052 // scalar code. 2053 if (I.getType()->isVectorTy()) 2054 return; 2055 2056 if (isa<CallInst>(I) || isa<InvokeInst>(I)) { 2057 if (const Function *F = cast<CallBase>(I).getCalledFunction()) { 2058 if (!isLoweredToCall(F)) 2059 continue; 2060 } 2061 return; 2062 } 2063 2064 SmallVector<const Value*, 4> Operands(I.operand_values()); 2065 Cost += 2066 getUserCost(&I, Operands, TargetTransformInfo::TCK_SizeAndLatency); 2067 } 2068 } 2069 2070 LLVM_DEBUG(dbgs() << "Cost of loop: " << Cost << "\n"); 2071 2072 UP.Partial = true; 2073 UP.Runtime = true; 2074 UP.UpperBound = true; 2075 UP.UnrollRemainder = true; 2076 UP.DefaultUnrollRuntimeCount = 4; 2077 UP.UnrollAndJam = true; 2078 UP.UnrollAndJamInnerLoopThreshold = 60; 2079 2080 // Force unrolling small loops can be very useful because of the branch 2081 // taken cost of the backedge. 2082 if (Cost < 12) 2083 UP.Force = true; 2084 } 2085 2086 void ARMTTIImpl::getPeelingPreferences(Loop *L, ScalarEvolution &SE, 2087 TTI::PeelingPreferences &PP) { 2088 BaseT::getPeelingPreferences(L, SE, PP); 2089 } 2090 2091 bool ARMTTIImpl::useReductionIntrinsic(unsigned Opcode, Type *Ty, 2092 TTI::ReductionFlags Flags) const { 2093 return ST->hasMVEIntegerOps(); 2094 } 2095 2096 bool ARMTTIImpl::preferInLoopReduction(unsigned Opcode, Type *Ty, 2097 TTI::ReductionFlags Flags) const { 2098 if (!ST->hasMVEIntegerOps()) 2099 return false; 2100 2101 unsigned ScalarBits = Ty->getScalarSizeInBits(); 2102 switch (Opcode) { 2103 case Instruction::Add: 2104 return ScalarBits <= 64; 2105 default: 2106 return false; 2107 } 2108 } 2109 2110 bool ARMTTIImpl::preferPredicatedReductionSelect( 2111 unsigned Opcode, Type *Ty, TTI::ReductionFlags Flags) const { 2112 if (!ST->hasMVEIntegerOps()) 2113 return false; 2114 return true; 2115 } 2116