| 1 | //===----------- VectorUtils.cpp - Vectorizer utility functions -----------===// |
| 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 | // This file defines vectorizer utilities. |
| 10 | // |
| 11 | //===----------------------------------------------------------------------===// |
| 12 | |
| 13 | #include "llvm/Analysis/VectorUtils.h" |
| 14 | #include "llvm/ADT/EquivalenceClasses.h" |
| 15 | #include "llvm/ADT/SmallVector.h" |
| 16 | #include "llvm/Analysis/DemandedBits.h" |
| 17 | #include "llvm/Analysis/LoopInfo.h" |
| 18 | #include "llvm/Analysis/LoopIterator.h" |
| 19 | #include "llvm/Analysis/ScalarEvolution.h" |
| 20 | #include "llvm/Analysis/ScalarEvolutionExpressions.h" |
| 21 | #include "llvm/Analysis/TargetTransformInfo.h" |
| 22 | #include "llvm/Analysis/ValueTracking.h" |
| 23 | #include "llvm/IR/Constants.h" |
| 24 | #include "llvm/IR/DerivedTypes.h" |
| 25 | #include "llvm/IR/IRBuilder.h" |
| 26 | #include "llvm/IR/MemoryModelRelaxationAnnotations.h" |
| 27 | #include "llvm/IR/PatternMatch.h" |
| 28 | #include "llvm/IR/Value.h" |
| 29 | #include "llvm/Support/CommandLine.h" |
| 30 | |
| 31 | #define DEBUG_TYPE "vectorutils" |
| 32 | |
| 33 | using namespace llvm; |
| 34 | using namespace llvm::PatternMatch; |
| 35 | |
| 36 | /// Maximum factor for an interleaved memory access. |
| 37 | static cl::opt<unsigned> MaxInterleaveGroupFactor( |
| 38 | "max-interleave-group-factor" , cl::Hidden, |
| 39 | cl::desc("Maximum factor for an interleaved access group (default = 8)" ), |
| 40 | cl::init(Val: 8)); |
| 41 | |
| 42 | /// Return true if all of the intrinsic's arguments and return type are scalars |
| 43 | /// for the scalar form of the intrinsic, and vectors for the vector form of the |
| 44 | /// intrinsic (except operands that are marked as always being scalar by |
| 45 | /// isVectorIntrinsicWithScalarOpAtArg). |
| 46 | bool llvm::isTriviallyVectorizable(Intrinsic::ID ID) { |
| 47 | switch (ID) { |
| 48 | case Intrinsic::abs: // Begin integer bit-manipulation. |
| 49 | case Intrinsic::bswap: |
| 50 | case Intrinsic::bitreverse: |
| 51 | case Intrinsic::ctpop: |
| 52 | case Intrinsic::ctlz: |
| 53 | case Intrinsic::cttz: |
| 54 | case Intrinsic::fshl: |
| 55 | case Intrinsic::fshr: |
| 56 | case Intrinsic::smax: |
| 57 | case Intrinsic::smin: |
| 58 | case Intrinsic::umax: |
| 59 | case Intrinsic::umin: |
| 60 | case Intrinsic::sadd_sat: |
| 61 | case Intrinsic::ssub_sat: |
| 62 | case Intrinsic::uadd_sat: |
| 63 | case Intrinsic::usub_sat: |
| 64 | case Intrinsic::smul_fix: |
| 65 | case Intrinsic::smul_fix_sat: |
| 66 | case Intrinsic::umul_fix: |
| 67 | case Intrinsic::umul_fix_sat: |
| 68 | case Intrinsic::sqrt: // Begin floating-point. |
| 69 | case Intrinsic::asin: |
| 70 | case Intrinsic::acos: |
| 71 | case Intrinsic::atan: |
| 72 | case Intrinsic::atan2: |
| 73 | case Intrinsic::sin: |
| 74 | case Intrinsic::cos: |
| 75 | case Intrinsic::sincos: |
| 76 | case Intrinsic::sincospi: |
| 77 | case Intrinsic::tan: |
| 78 | case Intrinsic::sinh: |
| 79 | case Intrinsic::cosh: |
| 80 | case Intrinsic::tanh: |
| 81 | case Intrinsic::exp: |
| 82 | case Intrinsic::exp10: |
| 83 | case Intrinsic::exp2: |
| 84 | case Intrinsic::log: |
| 85 | case Intrinsic::log10: |
| 86 | case Intrinsic::log2: |
| 87 | case Intrinsic::fabs: |
| 88 | case Intrinsic::minnum: |
| 89 | case Intrinsic::maxnum: |
| 90 | case Intrinsic::minimum: |
| 91 | case Intrinsic::maximum: |
| 92 | case Intrinsic::minimumnum: |
| 93 | case Intrinsic::maximumnum: |
| 94 | case Intrinsic::modf: |
| 95 | case Intrinsic::copysign: |
| 96 | case Intrinsic::floor: |
| 97 | case Intrinsic::ceil: |
| 98 | case Intrinsic::trunc: |
| 99 | case Intrinsic::rint: |
| 100 | case Intrinsic::nearbyint: |
| 101 | case Intrinsic::round: |
| 102 | case Intrinsic::roundeven: |
| 103 | case Intrinsic::pow: |
| 104 | case Intrinsic::fma: |
| 105 | case Intrinsic::fmuladd: |
| 106 | case Intrinsic::is_fpclass: |
| 107 | case Intrinsic::powi: |
| 108 | case Intrinsic::canonicalize: |
| 109 | case Intrinsic::fptosi_sat: |
| 110 | case Intrinsic::fptoui_sat: |
| 111 | case Intrinsic::lrint: |
| 112 | case Intrinsic::llrint: |
| 113 | case Intrinsic::ucmp: |
| 114 | case Intrinsic::scmp: |
| 115 | return true; |
| 116 | default: |
| 117 | return false; |
| 118 | } |
| 119 | } |
| 120 | |
| 121 | bool llvm::isTriviallyScalarizable(Intrinsic::ID ID, |
| 122 | const TargetTransformInfo *TTI) { |
| 123 | if (isTriviallyVectorizable(ID)) |
| 124 | return true; |
| 125 | |
| 126 | if (TTI && Intrinsic::isTargetIntrinsic(IID: ID)) |
| 127 | return TTI->isTargetIntrinsicTriviallyScalarizable(ID); |
| 128 | |
| 129 | // TODO: Move frexp to isTriviallyVectorizable. |
| 130 | // https://github.com/llvm/llvm-project/issues/112408 |
| 131 | switch (ID) { |
| 132 | case Intrinsic::frexp: |
| 133 | case Intrinsic::uadd_with_overflow: |
| 134 | case Intrinsic::sadd_with_overflow: |
| 135 | case Intrinsic::ssub_with_overflow: |
| 136 | case Intrinsic::usub_with_overflow: |
| 137 | case Intrinsic::umul_with_overflow: |
| 138 | case Intrinsic::smul_with_overflow: |
| 139 | return true; |
| 140 | } |
| 141 | return false; |
| 142 | } |
| 143 | |
| 144 | /// Identifies if the vector form of the intrinsic has a scalar operand. |
| 145 | bool llvm::isVectorIntrinsicWithScalarOpAtArg(Intrinsic::ID ID, |
| 146 | unsigned ScalarOpdIdx, |
| 147 | const TargetTransformInfo *TTI) { |
| 148 | |
| 149 | if (TTI && Intrinsic::isTargetIntrinsic(IID: ID)) |
| 150 | return TTI->isTargetIntrinsicWithScalarOpAtArg(ID, ScalarOpdIdx); |
| 151 | |
| 152 | // Vector predication intrinsics have the EVL as the last operand. |
| 153 | if (VPIntrinsic::getVectorLengthParamPos(IntrinsicID: ID) == ScalarOpdIdx) |
| 154 | return true; |
| 155 | |
| 156 | switch (ID) { |
| 157 | case Intrinsic::abs: |
| 158 | case Intrinsic::vp_abs: |
| 159 | case Intrinsic::ctlz: |
| 160 | case Intrinsic::vp_ctlz: |
| 161 | case Intrinsic::cttz: |
| 162 | case Intrinsic::vp_cttz: |
| 163 | case Intrinsic::is_fpclass: |
| 164 | case Intrinsic::vp_is_fpclass: |
| 165 | case Intrinsic::powi: |
| 166 | return (ScalarOpdIdx == 1); |
| 167 | case Intrinsic::smul_fix: |
| 168 | case Intrinsic::smul_fix_sat: |
| 169 | case Intrinsic::umul_fix: |
| 170 | case Intrinsic::umul_fix_sat: |
| 171 | return (ScalarOpdIdx == 2); |
| 172 | case Intrinsic::experimental_vp_splice: |
| 173 | return ScalarOpdIdx == 2 || ScalarOpdIdx == 4; |
| 174 | default: |
| 175 | return false; |
| 176 | } |
| 177 | } |
| 178 | |
| 179 | bool llvm::isVectorIntrinsicWithOverloadTypeAtArg( |
| 180 | Intrinsic::ID ID, int OpdIdx, const TargetTransformInfo *TTI) { |
| 181 | assert(ID != Intrinsic::not_intrinsic && "Not an intrinsic!" ); |
| 182 | |
| 183 | if (TTI && Intrinsic::isTargetIntrinsic(IID: ID)) |
| 184 | return TTI->isTargetIntrinsicWithOverloadTypeAtArg(ID, OpdIdx); |
| 185 | |
| 186 | if (VPCastIntrinsic::isVPCast(ID)) |
| 187 | return OpdIdx == -1 || OpdIdx == 0; |
| 188 | |
| 189 | switch (ID) { |
| 190 | case Intrinsic::fptosi_sat: |
| 191 | case Intrinsic::fptoui_sat: |
| 192 | case Intrinsic::lrint: |
| 193 | case Intrinsic::llrint: |
| 194 | case Intrinsic::vp_lrint: |
| 195 | case Intrinsic::vp_llrint: |
| 196 | case Intrinsic::ucmp: |
| 197 | case Intrinsic::scmp: |
| 198 | return OpdIdx == -1 || OpdIdx == 0; |
| 199 | case Intrinsic::modf: |
| 200 | case Intrinsic::sincos: |
| 201 | case Intrinsic::sincospi: |
| 202 | case Intrinsic::is_fpclass: |
| 203 | case Intrinsic::vp_is_fpclass: |
| 204 | return OpdIdx == 0; |
| 205 | case Intrinsic::powi: |
| 206 | return OpdIdx == -1 || OpdIdx == 1; |
| 207 | default: |
| 208 | return OpdIdx == -1; |
| 209 | } |
| 210 | } |
| 211 | |
| 212 | bool llvm::isVectorIntrinsicWithStructReturnOverloadAtField( |
| 213 | Intrinsic::ID ID, int RetIdx, const TargetTransformInfo *TTI) { |
| 214 | |
| 215 | if (TTI && Intrinsic::isTargetIntrinsic(IID: ID)) |
| 216 | return TTI->isTargetIntrinsicWithStructReturnOverloadAtField(ID, RetIdx); |
| 217 | |
| 218 | switch (ID) { |
| 219 | case Intrinsic::frexp: |
| 220 | return RetIdx == 0 || RetIdx == 1; |
| 221 | default: |
| 222 | return RetIdx == 0; |
| 223 | } |
| 224 | } |
| 225 | |
| 226 | /// Returns intrinsic ID for call. |
| 227 | /// For the input call instruction it finds mapping intrinsic and returns |
| 228 | /// its ID, in case it does not found it return not_intrinsic. |
| 229 | Intrinsic::ID llvm::getVectorIntrinsicIDForCall(const CallInst *CI, |
| 230 | const TargetLibraryInfo *TLI) { |
| 231 | Intrinsic::ID ID = getIntrinsicForCallSite(CB: *CI, TLI); |
| 232 | if (ID == Intrinsic::not_intrinsic) |
| 233 | return Intrinsic::not_intrinsic; |
| 234 | |
| 235 | if (isTriviallyVectorizable(ID) || ID == Intrinsic::lifetime_start || |
| 236 | ID == Intrinsic::lifetime_end || ID == Intrinsic::assume || |
| 237 | ID == Intrinsic::experimental_noalias_scope_decl || |
| 238 | ID == Intrinsic::sideeffect || ID == Intrinsic::pseudoprobe) |
| 239 | return ID; |
| 240 | return Intrinsic::not_intrinsic; |
| 241 | } |
| 242 | |
| 243 | struct InterleaveIntrinsic { |
| 244 | Intrinsic::ID Interleave, Deinterleave; |
| 245 | }; |
| 246 | |
| 247 | static InterleaveIntrinsic InterleaveIntrinsics[] = { |
| 248 | {.Interleave: Intrinsic::vector_interleave2, .Deinterleave: Intrinsic::vector_deinterleave2}, |
| 249 | {.Interleave: Intrinsic::vector_interleave3, .Deinterleave: Intrinsic::vector_deinterleave3}, |
| 250 | {.Interleave: Intrinsic::vector_interleave4, .Deinterleave: Intrinsic::vector_deinterleave4}, |
| 251 | {.Interleave: Intrinsic::vector_interleave5, .Deinterleave: Intrinsic::vector_deinterleave5}, |
| 252 | {.Interleave: Intrinsic::vector_interleave6, .Deinterleave: Intrinsic::vector_deinterleave6}, |
| 253 | {.Interleave: Intrinsic::vector_interleave7, .Deinterleave: Intrinsic::vector_deinterleave7}, |
| 254 | {.Interleave: Intrinsic::vector_interleave8, .Deinterleave: Intrinsic::vector_deinterleave8}, |
| 255 | }; |
| 256 | |
| 257 | Intrinsic::ID llvm::getInterleaveIntrinsicID(unsigned Factor) { |
| 258 | assert(Factor >= 2 && Factor <= 8 && "Unexpected factor" ); |
| 259 | return InterleaveIntrinsics[Factor - 2].Interleave; |
| 260 | } |
| 261 | |
| 262 | Intrinsic::ID llvm::getDeinterleaveIntrinsicID(unsigned Factor) { |
| 263 | assert(Factor >= 2 && Factor <= 8 && "Unexpected factor" ); |
| 264 | return InterleaveIntrinsics[Factor - 2].Deinterleave; |
| 265 | } |
| 266 | |
| 267 | /// Given a vector and an element number, see if the scalar value is |
| 268 | /// already around as a register, for example if it were inserted then extracted |
| 269 | /// from the vector. |
| 270 | Value *llvm::findScalarElement(Value *V, unsigned EltNo) { |
| 271 | assert(V->getType()->isVectorTy() && "Not looking at a vector?" ); |
| 272 | VectorType *VTy = cast<VectorType>(Val: V->getType()); |
| 273 | // For fixed-length vector, return poison for out of range access. |
| 274 | if (auto *FVTy = dyn_cast<FixedVectorType>(Val: VTy)) { |
| 275 | unsigned Width = FVTy->getNumElements(); |
| 276 | if (EltNo >= Width) |
| 277 | return PoisonValue::get(T: FVTy->getElementType()); |
| 278 | } |
| 279 | |
| 280 | if (Constant *C = dyn_cast<Constant>(Val: V)) |
| 281 | return C->getAggregateElement(Elt: EltNo); |
| 282 | |
| 283 | if (InsertElementInst *III = dyn_cast<InsertElementInst>(Val: V)) { |
| 284 | // If this is an insert to a variable element, we don't know what it is. |
| 285 | if (!isa<ConstantInt>(Val: III->getOperand(i_nocapture: 2))) |
| 286 | return nullptr; |
| 287 | unsigned IIElt = cast<ConstantInt>(Val: III->getOperand(i_nocapture: 2))->getZExtValue(); |
| 288 | |
| 289 | // If this is an insert to the element we are looking for, return the |
| 290 | // inserted value. |
| 291 | if (EltNo == IIElt) |
| 292 | return III->getOperand(i_nocapture: 1); |
| 293 | |
| 294 | // Guard against infinite loop on malformed, unreachable IR. |
| 295 | if (III == III->getOperand(i_nocapture: 0)) |
| 296 | return nullptr; |
| 297 | |
| 298 | // Otherwise, the insertelement doesn't modify the value, recurse on its |
| 299 | // vector input. |
| 300 | return findScalarElement(V: III->getOperand(i_nocapture: 0), EltNo); |
| 301 | } |
| 302 | |
| 303 | ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(Val: V); |
| 304 | // Restrict the following transformation to fixed-length vector. |
| 305 | if (SVI && isa<FixedVectorType>(Val: SVI->getType())) { |
| 306 | unsigned LHSWidth = |
| 307 | cast<FixedVectorType>(Val: SVI->getOperand(i_nocapture: 0)->getType())->getNumElements(); |
| 308 | int InEl = SVI->getMaskValue(Elt: EltNo); |
| 309 | if (InEl < 0) |
| 310 | return PoisonValue::get(T: VTy->getElementType()); |
| 311 | if (InEl < (int)LHSWidth) |
| 312 | return findScalarElement(V: SVI->getOperand(i_nocapture: 0), EltNo: InEl); |
| 313 | return findScalarElement(V: SVI->getOperand(i_nocapture: 1), EltNo: InEl - LHSWidth); |
| 314 | } |
| 315 | |
| 316 | // Extract a value from a vector add operation with a constant zero. |
| 317 | // TODO: Use getBinOpIdentity() to generalize this. |
| 318 | Value *Val; Constant *C; |
| 319 | if (match(V, P: m_Add(L: m_Value(V&: Val), R: m_Constant(C)))) |
| 320 | if (Constant *Elt = C->getAggregateElement(Elt: EltNo)) |
| 321 | if (Elt->isNullValue()) |
| 322 | return findScalarElement(V: Val, EltNo); |
| 323 | |
| 324 | // If the vector is a splat then we can trivially find the scalar element. |
| 325 | if (isa<ScalableVectorType>(Val: VTy)) |
| 326 | if (Value *Splat = getSplatValue(V)) |
| 327 | if (EltNo < VTy->getElementCount().getKnownMinValue()) |
| 328 | return Splat; |
| 329 | |
| 330 | // Otherwise, we don't know. |
| 331 | return nullptr; |
| 332 | } |
| 333 | |
| 334 | int llvm::getSplatIndex(ArrayRef<int> Mask) { |
| 335 | int SplatIndex = -1; |
| 336 | for (int M : Mask) { |
| 337 | // Ignore invalid (undefined) mask elements. |
| 338 | if (M < 0) |
| 339 | continue; |
| 340 | |
| 341 | // There can be only 1 non-negative mask element value if this is a splat. |
| 342 | if (SplatIndex != -1 && SplatIndex != M) |
| 343 | return -1; |
| 344 | |
| 345 | // Initialize the splat index to the 1st non-negative mask element. |
| 346 | SplatIndex = M; |
| 347 | } |
| 348 | assert((SplatIndex == -1 || SplatIndex >= 0) && "Negative index?" ); |
| 349 | return SplatIndex; |
| 350 | } |
| 351 | |
| 352 | /// Get splat value if the input is a splat vector or return nullptr. |
| 353 | /// This function is not fully general. It checks only 2 cases: |
| 354 | /// the input value is (1) a splat constant vector or (2) a sequence |
| 355 | /// of instructions that broadcasts a scalar at element 0. |
| 356 | Value *llvm::getSplatValue(const Value *V) { |
| 357 | if (isa<VectorType>(Val: V->getType())) |
| 358 | if (auto *C = dyn_cast<Constant>(Val: V)) |
| 359 | return C->getSplatValue(); |
| 360 | |
| 361 | // shuf (inselt ?, Splat, 0), ?, <0, undef, 0, ...> |
| 362 | Value *Splat; |
| 363 | if (match(V, |
| 364 | P: m_Shuffle(v1: m_InsertElt(Val: m_Value(), Elt: m_Value(V&: Splat), Idx: m_ZeroInt()), |
| 365 | v2: m_Value(), mask: m_ZeroMask()))) |
| 366 | return Splat; |
| 367 | |
| 368 | return nullptr; |
| 369 | } |
| 370 | |
| 371 | bool llvm::isSplatValue(const Value *V, int Index, unsigned Depth) { |
| 372 | assert(Depth <= MaxAnalysisRecursionDepth && "Limit Search Depth" ); |
| 373 | |
| 374 | if (isa<VectorType>(Val: V->getType())) { |
| 375 | if (isa<UndefValue>(Val: V)) |
| 376 | return true; |
| 377 | // FIXME: We can allow undefs, but if Index was specified, we may want to |
| 378 | // check that the constant is defined at that index. |
| 379 | if (auto *C = dyn_cast<Constant>(Val: V)) |
| 380 | return C->getSplatValue() != nullptr; |
| 381 | } |
| 382 | |
| 383 | if (auto *Shuf = dyn_cast<ShuffleVectorInst>(Val: V)) { |
| 384 | // FIXME: We can safely allow undefs here. If Index was specified, we will |
| 385 | // check that the mask elt is defined at the required index. |
| 386 | if (!all_equal(Range: Shuf->getShuffleMask())) |
| 387 | return false; |
| 388 | |
| 389 | // Match any index. |
| 390 | if (Index == -1) |
| 391 | return true; |
| 392 | |
| 393 | // Match a specific element. The mask should be defined at and match the |
| 394 | // specified index. |
| 395 | return Shuf->getMaskValue(Elt: Index) == Index; |
| 396 | } |
| 397 | |
| 398 | // The remaining tests are all recursive, so bail out if we hit the limit. |
| 399 | if (Depth++ == MaxAnalysisRecursionDepth) |
| 400 | return false; |
| 401 | |
| 402 | // If both operands of a binop are splats, the result is a splat. |
| 403 | Value *X, *Y, *Z; |
| 404 | if (match(V, P: m_BinOp(L: m_Value(V&: X), R: m_Value(V&: Y)))) |
| 405 | return isSplatValue(V: X, Index, Depth) && isSplatValue(V: Y, Index, Depth); |
| 406 | |
| 407 | // If all operands of a select are splats, the result is a splat. |
| 408 | if (match(V, P: m_Select(C: m_Value(V&: X), L: m_Value(V&: Y), R: m_Value(V&: Z)))) |
| 409 | return isSplatValue(V: X, Index, Depth) && isSplatValue(V: Y, Index, Depth) && |
| 410 | isSplatValue(V: Z, Index, Depth); |
| 411 | |
| 412 | // TODO: Add support for unary ops (fneg), casts, intrinsics (overflow ops). |
| 413 | |
| 414 | return false; |
| 415 | } |
| 416 | |
| 417 | bool llvm::getShuffleDemandedElts(int SrcWidth, ArrayRef<int> Mask, |
| 418 | const APInt &DemandedElts, APInt &DemandedLHS, |
| 419 | APInt &DemandedRHS, bool AllowUndefElts) { |
| 420 | DemandedLHS = DemandedRHS = APInt::getZero(numBits: SrcWidth); |
| 421 | |
| 422 | // Early out if we don't demand any elements. |
| 423 | if (DemandedElts.isZero()) |
| 424 | return true; |
| 425 | |
| 426 | // Simple case of a shuffle with zeroinitializer. |
| 427 | if (all_of(Range&: Mask, P: [](int Elt) { return Elt == 0; })) { |
| 428 | DemandedLHS.setBit(0); |
| 429 | return true; |
| 430 | } |
| 431 | |
| 432 | for (unsigned I = 0, E = Mask.size(); I != E; ++I) { |
| 433 | int M = Mask[I]; |
| 434 | assert((-1 <= M) && (M < (SrcWidth * 2)) && |
| 435 | "Invalid shuffle mask constant" ); |
| 436 | |
| 437 | if (!DemandedElts[I] || (AllowUndefElts && (M < 0))) |
| 438 | continue; |
| 439 | |
| 440 | // For undef elements, we don't know anything about the common state of |
| 441 | // the shuffle result. |
| 442 | if (M < 0) |
| 443 | return false; |
| 444 | |
| 445 | if (M < SrcWidth) |
| 446 | DemandedLHS.setBit(M); |
| 447 | else |
| 448 | DemandedRHS.setBit(M - SrcWidth); |
| 449 | } |
| 450 | |
| 451 | return true; |
| 452 | } |
| 453 | |
| 454 | bool llvm::isMaskedSlidePair(ArrayRef<int> Mask, int NumElts, |
| 455 | std::array<std::pair<int, int>, 2> &SrcInfo) { |
| 456 | const int SignalValue = NumElts * 2; |
| 457 | SrcInfo[0] = {-1, SignalValue}; |
| 458 | SrcInfo[1] = {-1, SignalValue}; |
| 459 | for (auto [i, M] : enumerate(First&: Mask)) { |
| 460 | if (M < 0) |
| 461 | continue; |
| 462 | int Src = M >= (int)NumElts; |
| 463 | int Diff = (int)i - (M % NumElts); |
| 464 | bool Match = false; |
| 465 | for (int j = 0; j < 2; j++) { |
| 466 | auto &[SrcE, DiffE] = SrcInfo[j]; |
| 467 | if (SrcE == -1) { |
| 468 | assert(DiffE == SignalValue); |
| 469 | SrcE = Src; |
| 470 | DiffE = Diff; |
| 471 | } |
| 472 | if (SrcE == Src && DiffE == Diff) { |
| 473 | Match = true; |
| 474 | break; |
| 475 | } |
| 476 | } |
| 477 | if (!Match) |
| 478 | return false; |
| 479 | } |
| 480 | // Avoid all undef masks |
| 481 | return SrcInfo[0].first != -1; |
| 482 | } |
| 483 | |
| 484 | void llvm::narrowShuffleMaskElts(int Scale, ArrayRef<int> Mask, |
| 485 | SmallVectorImpl<int> &ScaledMask) { |
| 486 | assert(Scale > 0 && "Unexpected scaling factor" ); |
| 487 | |
| 488 | // Fast-path: if no scaling, then it is just a copy. |
| 489 | if (Scale == 1) { |
| 490 | ScaledMask.assign(in_start: Mask.begin(), in_end: Mask.end()); |
| 491 | return; |
| 492 | } |
| 493 | |
| 494 | ScaledMask.clear(); |
| 495 | for (int MaskElt : Mask) { |
| 496 | if (MaskElt >= 0) { |
| 497 | assert(((uint64_t)Scale * MaskElt + (Scale - 1)) <= INT32_MAX && |
| 498 | "Overflowed 32-bits" ); |
| 499 | } |
| 500 | for (int SliceElt = 0; SliceElt != Scale; ++SliceElt) |
| 501 | ScaledMask.push_back(Elt: MaskElt < 0 ? MaskElt : Scale * MaskElt + SliceElt); |
| 502 | } |
| 503 | } |
| 504 | |
| 505 | bool llvm::widenShuffleMaskElts(int Scale, ArrayRef<int> Mask, |
| 506 | SmallVectorImpl<int> &ScaledMask) { |
| 507 | assert(Scale > 0 && "Unexpected scaling factor" ); |
| 508 | |
| 509 | // Fast-path: if no scaling, then it is just a copy. |
| 510 | if (Scale == 1) { |
| 511 | ScaledMask.assign(in_start: Mask.begin(), in_end: Mask.end()); |
| 512 | return true; |
| 513 | } |
| 514 | |
| 515 | // We must map the original elements down evenly to a type with less elements. |
| 516 | int NumElts = Mask.size(); |
| 517 | if (NumElts % Scale != 0) |
| 518 | return false; |
| 519 | |
| 520 | ScaledMask.clear(); |
| 521 | ScaledMask.reserve(N: NumElts / Scale); |
| 522 | |
| 523 | // Step through the input mask by splitting into Scale-sized slices. |
| 524 | do { |
| 525 | ArrayRef<int> MaskSlice = Mask.take_front(N: Scale); |
| 526 | assert((int)MaskSlice.size() == Scale && "Expected Scale-sized slice." ); |
| 527 | |
| 528 | // The first element of the slice determines how we evaluate this slice. |
| 529 | int SliceFront = MaskSlice.front(); |
| 530 | if (SliceFront < 0) { |
| 531 | // Negative values (undef or other "sentinel" values) must be equal across |
| 532 | // the entire slice. |
| 533 | if (!all_equal(Range&: MaskSlice)) |
| 534 | return false; |
| 535 | ScaledMask.push_back(Elt: SliceFront); |
| 536 | } else { |
| 537 | // A positive mask element must be cleanly divisible. |
| 538 | if (SliceFront % Scale != 0) |
| 539 | return false; |
| 540 | // Elements of the slice must be consecutive. |
| 541 | for (int i = 1; i < Scale; ++i) |
| 542 | if (MaskSlice[i] != SliceFront + i) |
| 543 | return false; |
| 544 | ScaledMask.push_back(Elt: SliceFront / Scale); |
| 545 | } |
| 546 | Mask = Mask.drop_front(N: Scale); |
| 547 | } while (!Mask.empty()); |
| 548 | |
| 549 | assert((int)ScaledMask.size() * Scale == NumElts && "Unexpected scaled mask" ); |
| 550 | |
| 551 | // All elements of the original mask can be scaled down to map to the elements |
| 552 | // of a mask with wider elements. |
| 553 | return true; |
| 554 | } |
| 555 | |
| 556 | bool llvm::widenShuffleMaskElts(ArrayRef<int> M, |
| 557 | SmallVectorImpl<int> &NewMask) { |
| 558 | unsigned NumElts = M.size(); |
| 559 | if (NumElts % 2 != 0) |
| 560 | return false; |
| 561 | |
| 562 | NewMask.clear(); |
| 563 | for (unsigned i = 0; i < NumElts; i += 2) { |
| 564 | int M0 = M[i]; |
| 565 | int M1 = M[i + 1]; |
| 566 | |
| 567 | // If both elements are undef, new mask is undef too. |
| 568 | if (M0 == -1 && M1 == -1) { |
| 569 | NewMask.push_back(Elt: -1); |
| 570 | continue; |
| 571 | } |
| 572 | |
| 573 | if (M0 == -1 && M1 != -1 && (M1 % 2) == 1) { |
| 574 | NewMask.push_back(Elt: M1 / 2); |
| 575 | continue; |
| 576 | } |
| 577 | |
| 578 | if (M0 != -1 && (M0 % 2) == 0 && ((M0 + 1) == M1 || M1 == -1)) { |
| 579 | NewMask.push_back(Elt: M0 / 2); |
| 580 | continue; |
| 581 | } |
| 582 | |
| 583 | NewMask.clear(); |
| 584 | return false; |
| 585 | } |
| 586 | |
| 587 | assert(NewMask.size() == NumElts / 2 && "Incorrect size for mask!" ); |
| 588 | return true; |
| 589 | } |
| 590 | |
| 591 | bool llvm::scaleShuffleMaskElts(unsigned NumDstElts, ArrayRef<int> Mask, |
| 592 | SmallVectorImpl<int> &ScaledMask) { |
| 593 | unsigned NumSrcElts = Mask.size(); |
| 594 | assert(NumSrcElts > 0 && NumDstElts > 0 && "Unexpected scaling factor" ); |
| 595 | |
| 596 | // Fast-path: if no scaling, then it is just a copy. |
| 597 | if (NumSrcElts == NumDstElts) { |
| 598 | ScaledMask.assign(in_start: Mask.begin(), in_end: Mask.end()); |
| 599 | return true; |
| 600 | } |
| 601 | |
| 602 | // Ensure we can find a whole scale factor. |
| 603 | assert(((NumSrcElts % NumDstElts) == 0 || (NumDstElts % NumSrcElts) == 0) && |
| 604 | "Unexpected scaling factor" ); |
| 605 | |
| 606 | if (NumSrcElts > NumDstElts) { |
| 607 | int Scale = NumSrcElts / NumDstElts; |
| 608 | return widenShuffleMaskElts(Scale, Mask, ScaledMask); |
| 609 | } |
| 610 | |
| 611 | int Scale = NumDstElts / NumSrcElts; |
| 612 | narrowShuffleMaskElts(Scale, Mask, ScaledMask); |
| 613 | return true; |
| 614 | } |
| 615 | |
| 616 | void llvm::getShuffleMaskWithWidestElts(ArrayRef<int> Mask, |
| 617 | SmallVectorImpl<int> &ScaledMask) { |
| 618 | std::array<SmallVector<int, 16>, 2> TmpMasks; |
| 619 | SmallVectorImpl<int> *Output = &TmpMasks[0], *Tmp = &TmpMasks[1]; |
| 620 | ArrayRef<int> InputMask = Mask; |
| 621 | for (unsigned Scale = 2; Scale <= InputMask.size(); ++Scale) { |
| 622 | while (widenShuffleMaskElts(Scale, Mask: InputMask, ScaledMask&: *Output)) { |
| 623 | InputMask = *Output; |
| 624 | std::swap(a&: Output, b&: Tmp); |
| 625 | } |
| 626 | } |
| 627 | ScaledMask.assign(in_start: InputMask.begin(), in_end: InputMask.end()); |
| 628 | } |
| 629 | |
| 630 | void llvm::processShuffleMasks( |
| 631 | ArrayRef<int> Mask, unsigned NumOfSrcRegs, unsigned NumOfDestRegs, |
| 632 | unsigned NumOfUsedRegs, function_ref<void()> NoInputAction, |
| 633 | function_ref<void(ArrayRef<int>, unsigned, unsigned)> SingleInputAction, |
| 634 | function_ref<void(ArrayRef<int>, unsigned, unsigned, bool)> |
| 635 | ManyInputsAction) { |
| 636 | SmallVector<SmallVector<SmallVector<int>>> Res(NumOfDestRegs); |
| 637 | // Try to perform better estimation of the permutation. |
| 638 | // 1. Split the source/destination vectors into real registers. |
| 639 | // 2. Do the mask analysis to identify which real registers are |
| 640 | // permuted. |
| 641 | int Sz = Mask.size(); |
| 642 | unsigned SzDest = Sz / NumOfDestRegs; |
| 643 | unsigned SzSrc = Sz / NumOfSrcRegs; |
| 644 | for (unsigned I = 0; I < NumOfDestRegs; ++I) { |
| 645 | auto &RegMasks = Res[I]; |
| 646 | RegMasks.assign(NumElts: 2 * NumOfSrcRegs, Elt: {}); |
| 647 | // Check that the values in dest registers are in the one src |
| 648 | // register. |
| 649 | for (unsigned K = 0; K < SzDest; ++K) { |
| 650 | int Idx = I * SzDest + K; |
| 651 | if (Idx == Sz) |
| 652 | break; |
| 653 | if (Mask[Idx] >= 2 * Sz || Mask[Idx] == PoisonMaskElem) |
| 654 | continue; |
| 655 | int MaskIdx = Mask[Idx] % Sz; |
| 656 | int SrcRegIdx = MaskIdx / SzSrc + (Mask[Idx] >= Sz ? NumOfSrcRegs : 0); |
| 657 | // Add a cost of PermuteTwoSrc for each new source register permute, |
| 658 | // if we have more than one source registers. |
| 659 | if (RegMasks[SrcRegIdx].empty()) |
| 660 | RegMasks[SrcRegIdx].assign(NumElts: SzDest, Elt: PoisonMaskElem); |
| 661 | RegMasks[SrcRegIdx][K] = MaskIdx % SzSrc; |
| 662 | } |
| 663 | } |
| 664 | // Process split mask. |
| 665 | for (unsigned I : seq<unsigned>(Size: NumOfUsedRegs)) { |
| 666 | auto &Dest = Res[I]; |
| 667 | int NumSrcRegs = |
| 668 | count_if(Range&: Dest, P: [](ArrayRef<int> Mask) { return !Mask.empty(); }); |
| 669 | switch (NumSrcRegs) { |
| 670 | case 0: |
| 671 | // No input vectors were used! |
| 672 | NoInputAction(); |
| 673 | break; |
| 674 | case 1: { |
| 675 | // Find the only mask with at least single undef mask elem. |
| 676 | auto *It = |
| 677 | find_if(Range&: Dest, P: [](ArrayRef<int> Mask) { return !Mask.empty(); }); |
| 678 | unsigned SrcReg = std::distance(first: Dest.begin(), last: It); |
| 679 | SingleInputAction(*It, SrcReg, I); |
| 680 | break; |
| 681 | } |
| 682 | default: { |
| 683 | // The first mask is a permutation of a single register. Since we have >2 |
| 684 | // input registers to shuffle, we merge the masks for 2 first registers |
| 685 | // and generate a shuffle of 2 registers rather than the reordering of the |
| 686 | // first register and then shuffle with the second register. Next, |
| 687 | // generate the shuffles of the resulting register + the remaining |
| 688 | // registers from the list. |
| 689 | auto &&CombineMasks = [](MutableArrayRef<int> FirstMask, |
| 690 | ArrayRef<int> SecondMask) { |
| 691 | for (int Idx = 0, VF = FirstMask.size(); Idx < VF; ++Idx) { |
| 692 | if (SecondMask[Idx] != PoisonMaskElem) { |
| 693 | assert(FirstMask[Idx] == PoisonMaskElem && |
| 694 | "Expected undefined mask element." ); |
| 695 | FirstMask[Idx] = SecondMask[Idx] + VF; |
| 696 | } |
| 697 | } |
| 698 | }; |
| 699 | auto &&NormalizeMask = [](MutableArrayRef<int> Mask) { |
| 700 | for (int Idx = 0, VF = Mask.size(); Idx < VF; ++Idx) { |
| 701 | if (Mask[Idx] != PoisonMaskElem) |
| 702 | Mask[Idx] = Idx; |
| 703 | } |
| 704 | }; |
| 705 | int SecondIdx; |
| 706 | bool NewReg = true; |
| 707 | do { |
| 708 | int FirstIdx = -1; |
| 709 | SecondIdx = -1; |
| 710 | MutableArrayRef<int> FirstMask, SecondMask; |
| 711 | for (unsigned I : seq<unsigned>(Size: 2 * NumOfSrcRegs)) { |
| 712 | SmallVectorImpl<int> &RegMask = Dest[I]; |
| 713 | if (RegMask.empty()) |
| 714 | continue; |
| 715 | |
| 716 | if (FirstIdx == SecondIdx) { |
| 717 | FirstIdx = I; |
| 718 | FirstMask = RegMask; |
| 719 | continue; |
| 720 | } |
| 721 | SecondIdx = I; |
| 722 | SecondMask = RegMask; |
| 723 | CombineMasks(FirstMask, SecondMask); |
| 724 | ManyInputsAction(FirstMask, FirstIdx, SecondIdx, NewReg); |
| 725 | NewReg = false; |
| 726 | NormalizeMask(FirstMask); |
| 727 | RegMask.clear(); |
| 728 | SecondMask = FirstMask; |
| 729 | SecondIdx = FirstIdx; |
| 730 | } |
| 731 | if (FirstIdx != SecondIdx && SecondIdx >= 0) { |
| 732 | CombineMasks(SecondMask, FirstMask); |
| 733 | ManyInputsAction(SecondMask, SecondIdx, FirstIdx, NewReg); |
| 734 | NewReg = false; |
| 735 | Dest[FirstIdx].clear(); |
| 736 | NormalizeMask(SecondMask); |
| 737 | } |
| 738 | } while (SecondIdx >= 0); |
| 739 | break; |
| 740 | } |
| 741 | } |
| 742 | } |
| 743 | } |
| 744 | |
| 745 | void llvm::getHorizDemandedEltsForFirstOperand(unsigned VectorBitWidth, |
| 746 | const APInt &DemandedElts, |
| 747 | APInt &DemandedLHS, |
| 748 | APInt &DemandedRHS) { |
| 749 | assert(VectorBitWidth >= 128 && "Vectors smaller than 128 bit not supported" ); |
| 750 | int NumLanes = VectorBitWidth / 128; |
| 751 | int NumElts = DemandedElts.getBitWidth(); |
| 752 | int NumEltsPerLane = NumElts / NumLanes; |
| 753 | int HalfEltsPerLane = NumEltsPerLane / 2; |
| 754 | |
| 755 | DemandedLHS = APInt::getZero(numBits: NumElts); |
| 756 | DemandedRHS = APInt::getZero(numBits: NumElts); |
| 757 | |
| 758 | // Map DemandedElts to the horizontal operands. |
| 759 | for (int Idx = 0; Idx != NumElts; ++Idx) { |
| 760 | if (!DemandedElts[Idx]) |
| 761 | continue; |
| 762 | int LaneIdx = (Idx / NumEltsPerLane) * NumEltsPerLane; |
| 763 | int LocalIdx = Idx % NumEltsPerLane; |
| 764 | if (LocalIdx < HalfEltsPerLane) { |
| 765 | DemandedLHS.setBit(LaneIdx + 2 * LocalIdx); |
| 766 | } else { |
| 767 | LocalIdx -= HalfEltsPerLane; |
| 768 | DemandedRHS.setBit(LaneIdx + 2 * LocalIdx); |
| 769 | } |
| 770 | } |
| 771 | } |
| 772 | |
| 773 | MapVector<Instruction *, uint64_t> |
| 774 | llvm::computeMinimumValueSizes(ArrayRef<BasicBlock *> Blocks, DemandedBits &DB, |
| 775 | const TargetTransformInfo *TTI) { |
| 776 | |
| 777 | // DemandedBits will give us every value's live-out bits. But we want |
| 778 | // to ensure no extra casts would need to be inserted, so every DAG |
| 779 | // of connected values must have the same minimum bitwidth. |
| 780 | EquivalenceClasses<Value *> ECs; |
| 781 | SmallVector<Instruction *, 16> Worklist; |
| 782 | SmallPtrSet<Instruction *, 4> Roots; |
| 783 | SmallPtrSet<Instruction *, 16> Visited; |
| 784 | DenseMap<Value *, uint64_t> DBits; |
| 785 | SmallPtrSet<Instruction *, 4> InstructionSet; |
| 786 | MapVector<Instruction *, uint64_t> MinBWs; |
| 787 | |
| 788 | // Determine the roots. We work bottom-up, from truncs or icmps. |
| 789 | bool SeenExtFromIllegalType = false; |
| 790 | for (auto *BB : Blocks) |
| 791 | for (auto &I : *BB) { |
| 792 | InstructionSet.insert(Ptr: &I); |
| 793 | |
| 794 | if (TTI && (isa<ZExtInst>(Val: &I) || isa<SExtInst>(Val: &I)) && |
| 795 | !TTI->isTypeLegal(Ty: I.getOperand(i: 0)->getType())) |
| 796 | SeenExtFromIllegalType = true; |
| 797 | |
| 798 | // Only deal with non-vector integers up to 64-bits wide. |
| 799 | if ((isa<TruncInst>(Val: &I) || isa<ICmpInst>(Val: &I)) && |
| 800 | !I.getType()->isVectorTy() && |
| 801 | I.getOperand(i: 0)->getType()->getScalarSizeInBits() <= 64) { |
| 802 | // Don't make work for ourselves. If we know the loaded type is legal, |
| 803 | // don't add it to the worklist. |
| 804 | if (TTI && isa<TruncInst>(Val: &I) && TTI->isTypeLegal(Ty: I.getType())) |
| 805 | continue; |
| 806 | |
| 807 | Worklist.push_back(Elt: &I); |
| 808 | Roots.insert(Ptr: &I); |
| 809 | } |
| 810 | } |
| 811 | // Early exit. |
| 812 | if (Worklist.empty() || (TTI && !SeenExtFromIllegalType)) |
| 813 | return MinBWs; |
| 814 | |
| 815 | // Now proceed breadth-first, unioning values together. |
| 816 | while (!Worklist.empty()) { |
| 817 | Instruction *I = Worklist.pop_back_val(); |
| 818 | Value *Leader = ECs.getOrInsertLeaderValue(V: I); |
| 819 | |
| 820 | if (!Visited.insert(Ptr: I).second) |
| 821 | continue; |
| 822 | |
| 823 | // If we encounter a type that is larger than 64 bits, we can't represent |
| 824 | // it so bail out. |
| 825 | if (DB.getDemandedBits(I).getBitWidth() > 64) |
| 826 | return MapVector<Instruction *, uint64_t>(); |
| 827 | |
| 828 | uint64_t V = DB.getDemandedBits(I).getZExtValue(); |
| 829 | DBits[Leader] |= V; |
| 830 | DBits[I] = V; |
| 831 | |
| 832 | // Casts, loads and instructions outside of our range terminate a chain |
| 833 | // successfully. |
| 834 | if (isa<SExtInst>(Val: I) || isa<ZExtInst>(Val: I) || isa<LoadInst>(Val: I) || |
| 835 | !InstructionSet.count(Ptr: I)) |
| 836 | continue; |
| 837 | |
| 838 | // Unsafe casts terminate a chain unsuccessfully. We can't do anything |
| 839 | // useful with bitcasts, ptrtoints or inttoptrs and it'd be unsafe to |
| 840 | // transform anything that relies on them. |
| 841 | if (isa<BitCastInst>(Val: I) || isa<PtrToIntInst>(Val: I) || isa<IntToPtrInst>(Val: I) || |
| 842 | !I->getType()->isIntegerTy()) { |
| 843 | DBits[Leader] |= ~0ULL; |
| 844 | continue; |
| 845 | } |
| 846 | |
| 847 | // We don't modify the types of PHIs. Reductions will already have been |
| 848 | // truncated if possible, and inductions' sizes will have been chosen by |
| 849 | // indvars. |
| 850 | if (isa<PHINode>(Val: I)) |
| 851 | continue; |
| 852 | |
| 853 | // Don't modify the types of operands of a call, as doing that would cause a |
| 854 | // signature mismatch. |
| 855 | if (isa<CallBase>(Val: I)) |
| 856 | continue; |
| 857 | |
| 858 | if (DBits[Leader] == ~0ULL) |
| 859 | // All bits demanded, no point continuing. |
| 860 | continue; |
| 861 | |
| 862 | for (Value *O : I->operands()) { |
| 863 | ECs.unionSets(V1: Leader, V2: O); |
| 864 | if (auto *OI = dyn_cast<Instruction>(Val: O)) |
| 865 | Worklist.push_back(Elt: OI); |
| 866 | } |
| 867 | } |
| 868 | |
| 869 | // Now we've discovered all values, walk them to see if there are |
| 870 | // any users we didn't see. If there are, we can't optimize that |
| 871 | // chain. |
| 872 | for (auto &I : DBits) |
| 873 | for (auto *U : I.first->users()) |
| 874 | if (U->getType()->isIntegerTy() && DBits.count(Val: U) == 0) |
| 875 | DBits[ECs.getOrInsertLeaderValue(V: I.first)] |= ~0ULL; |
| 876 | |
| 877 | for (const auto &E : ECs) { |
| 878 | if (!E->isLeader()) |
| 879 | continue; |
| 880 | uint64_t LeaderDemandedBits = 0; |
| 881 | for (Value *M : ECs.members(ECV: *E)) |
| 882 | LeaderDemandedBits |= DBits[M]; |
| 883 | |
| 884 | uint64_t MinBW = llvm::bit_width(Value: LeaderDemandedBits); |
| 885 | // Round up to a power of 2 |
| 886 | MinBW = llvm::bit_ceil(Value: MinBW); |
| 887 | |
| 888 | // We don't modify the types of PHIs. Reductions will already have been |
| 889 | // truncated if possible, and inductions' sizes will have been chosen by |
| 890 | // indvars. |
| 891 | // If we are required to shrink a PHI, abandon this entire equivalence class. |
| 892 | bool Abort = false; |
| 893 | for (Value *M : ECs.members(ECV: *E)) |
| 894 | if (isa<PHINode>(Val: M) && MinBW < M->getType()->getScalarSizeInBits()) { |
| 895 | Abort = true; |
| 896 | break; |
| 897 | } |
| 898 | if (Abort) |
| 899 | continue; |
| 900 | |
| 901 | for (Value *M : ECs.members(ECV: *E)) { |
| 902 | auto *MI = dyn_cast<Instruction>(Val: M); |
| 903 | if (!MI) |
| 904 | continue; |
| 905 | Type *Ty = M->getType(); |
| 906 | if (Roots.count(Ptr: MI)) |
| 907 | Ty = MI->getOperand(i: 0)->getType(); |
| 908 | |
| 909 | if (MinBW >= Ty->getScalarSizeInBits()) |
| 910 | continue; |
| 911 | |
| 912 | // If any of M's operands demand more bits than MinBW then M cannot be |
| 913 | // performed safely in MinBW. |
| 914 | auto *Call = dyn_cast<CallBase>(Val: MI); |
| 915 | auto Ops = Call ? Call->args() : MI->operands(); |
| 916 | if (any_of(Range&: Ops, P: [&DB, MinBW](Use &U) { |
| 917 | auto *CI = dyn_cast<ConstantInt>(Val&: U); |
| 918 | // For constants shift amounts, check if the shift would result in |
| 919 | // poison. |
| 920 | if (CI && |
| 921 | isa<ShlOperator, LShrOperator, AShrOperator>(Val: U.getUser()) && |
| 922 | U.getOperandNo() == 1) |
| 923 | return CI->uge(Num: MinBW); |
| 924 | uint64_t BW = bit_width(Value: DB.getDemandedBits(U: &U).getZExtValue()); |
| 925 | return bit_ceil(Value: BW) > MinBW; |
| 926 | })) |
| 927 | continue; |
| 928 | |
| 929 | MinBWs[MI] = MinBW; |
| 930 | } |
| 931 | } |
| 932 | |
| 933 | return MinBWs; |
| 934 | } |
| 935 | |
| 936 | /// Add all access groups in @p AccGroups to @p List. |
| 937 | template <typename ListT> |
| 938 | static void addToAccessGroupList(ListT &List, MDNode *AccGroups) { |
| 939 | // Interpret an access group as a list containing itself. |
| 940 | if (AccGroups->getNumOperands() == 0) { |
| 941 | assert(isValidAsAccessGroup(AccGroups) && "Node must be an access group" ); |
| 942 | List.insert(AccGroups); |
| 943 | return; |
| 944 | } |
| 945 | |
| 946 | for (const auto &AccGroupListOp : AccGroups->operands()) { |
| 947 | auto *Item = cast<MDNode>(Val: AccGroupListOp.get()); |
| 948 | assert(isValidAsAccessGroup(Item) && "List item must be an access group" ); |
| 949 | List.insert(Item); |
| 950 | } |
| 951 | } |
| 952 | |
| 953 | MDNode *llvm::uniteAccessGroups(MDNode *AccGroups1, MDNode *AccGroups2) { |
| 954 | if (!AccGroups1) |
| 955 | return AccGroups2; |
| 956 | if (!AccGroups2) |
| 957 | return AccGroups1; |
| 958 | if (AccGroups1 == AccGroups2) |
| 959 | return AccGroups1; |
| 960 | |
| 961 | SmallSetVector<Metadata *, 4> Union; |
| 962 | addToAccessGroupList(List&: Union, AccGroups: AccGroups1); |
| 963 | addToAccessGroupList(List&: Union, AccGroups: AccGroups2); |
| 964 | |
| 965 | if (Union.size() == 0) |
| 966 | return nullptr; |
| 967 | if (Union.size() == 1) |
| 968 | return cast<MDNode>(Val: Union.front()); |
| 969 | |
| 970 | LLVMContext &Ctx = AccGroups1->getContext(); |
| 971 | return MDNode::get(Context&: Ctx, MDs: Union.getArrayRef()); |
| 972 | } |
| 973 | |
| 974 | MDNode *llvm::intersectAccessGroups(const Instruction *Inst1, |
| 975 | const Instruction *Inst2) { |
| 976 | bool MayAccessMem1 = Inst1->mayReadOrWriteMemory(); |
| 977 | bool MayAccessMem2 = Inst2->mayReadOrWriteMemory(); |
| 978 | |
| 979 | if (!MayAccessMem1 && !MayAccessMem2) |
| 980 | return nullptr; |
| 981 | if (!MayAccessMem1) |
| 982 | return Inst2->getMetadata(KindID: LLVMContext::MD_access_group); |
| 983 | if (!MayAccessMem2) |
| 984 | return Inst1->getMetadata(KindID: LLVMContext::MD_access_group); |
| 985 | |
| 986 | MDNode *MD1 = Inst1->getMetadata(KindID: LLVMContext::MD_access_group); |
| 987 | MDNode *MD2 = Inst2->getMetadata(KindID: LLVMContext::MD_access_group); |
| 988 | if (!MD1 || !MD2) |
| 989 | return nullptr; |
| 990 | if (MD1 == MD2) |
| 991 | return MD1; |
| 992 | |
| 993 | // Use set for scalable 'contains' check. |
| 994 | SmallPtrSet<Metadata *, 4> AccGroupSet2; |
| 995 | addToAccessGroupList(List&: AccGroupSet2, AccGroups: MD2); |
| 996 | |
| 997 | SmallVector<Metadata *, 4> Intersection; |
| 998 | if (MD1->getNumOperands() == 0) { |
| 999 | assert(isValidAsAccessGroup(MD1) && "Node must be an access group" ); |
| 1000 | if (AccGroupSet2.count(Ptr: MD1)) |
| 1001 | Intersection.push_back(Elt: MD1); |
| 1002 | } else { |
| 1003 | for (const MDOperand &Node : MD1->operands()) { |
| 1004 | auto *Item = cast<MDNode>(Val: Node.get()); |
| 1005 | assert(isValidAsAccessGroup(Item) && "List item must be an access group" ); |
| 1006 | if (AccGroupSet2.count(Ptr: Item)) |
| 1007 | Intersection.push_back(Elt: Item); |
| 1008 | } |
| 1009 | } |
| 1010 | |
| 1011 | if (Intersection.size() == 0) |
| 1012 | return nullptr; |
| 1013 | if (Intersection.size() == 1) |
| 1014 | return cast<MDNode>(Val: Intersection.front()); |
| 1015 | |
| 1016 | LLVMContext &Ctx = Inst1->getContext(); |
| 1017 | return MDNode::get(Context&: Ctx, MDs: Intersection); |
| 1018 | } |
| 1019 | |
| 1020 | /// Add metadata from \p Inst to \p Metadata, if it can be preserved after |
| 1021 | /// vectorization. |
| 1022 | void llvm::getMetadataToPropagate( |
| 1023 | Instruction *Inst, |
| 1024 | SmallVectorImpl<std::pair<unsigned, MDNode *>> &Metadata) { |
| 1025 | Inst->getAllMetadataOtherThanDebugLoc(MDs&: Metadata); |
| 1026 | static const unsigned SupportedIDs[] = { |
| 1027 | LLVMContext::MD_tbaa, LLVMContext::MD_alias_scope, |
| 1028 | LLVMContext::MD_noalias, LLVMContext::MD_fpmath, |
| 1029 | LLVMContext::MD_nontemporal, LLVMContext::MD_invariant_load, |
| 1030 | LLVMContext::MD_access_group, LLVMContext::MD_mmra}; |
| 1031 | |
| 1032 | // Remove any unsupported metadata kinds from Metadata. |
| 1033 | for (unsigned Idx = 0; Idx != Metadata.size();) { |
| 1034 | if (is_contained(Range: SupportedIDs, Element: Metadata[Idx].first)) { |
| 1035 | ++Idx; |
| 1036 | } else { |
| 1037 | // Swap element to end and remove it. |
| 1038 | std::swap(x&: Metadata[Idx], y&: Metadata.back()); |
| 1039 | Metadata.pop_back(); |
| 1040 | } |
| 1041 | } |
| 1042 | } |
| 1043 | |
| 1044 | /// \returns \p I after propagating metadata from \p VL. |
| 1045 | Instruction *llvm::propagateMetadata(Instruction *Inst, ArrayRef<Value *> VL) { |
| 1046 | if (VL.empty()) |
| 1047 | return Inst; |
| 1048 | SmallVector<std::pair<unsigned, MDNode *>> Metadata; |
| 1049 | getMetadataToPropagate(Inst: cast<Instruction>(Val: VL[0]), Metadata); |
| 1050 | |
| 1051 | for (auto &[Kind, MD] : Metadata) { |
| 1052 | for (int J = 1, E = VL.size(); MD && J != E; ++J) { |
| 1053 | const Instruction *IJ = cast<Instruction>(Val: VL[J]); |
| 1054 | MDNode *IMD = IJ->getMetadata(KindID: Kind); |
| 1055 | |
| 1056 | switch (Kind) { |
| 1057 | case LLVMContext::MD_mmra: { |
| 1058 | MD = MMRAMetadata::combine(Ctx&: Inst->getContext(), A: MD, B: IMD); |
| 1059 | break; |
| 1060 | } |
| 1061 | case LLVMContext::MD_tbaa: |
| 1062 | MD = MDNode::getMostGenericTBAA(A: MD, B: IMD); |
| 1063 | break; |
| 1064 | case LLVMContext::MD_alias_scope: |
| 1065 | MD = MDNode::getMostGenericAliasScope(A: MD, B: IMD); |
| 1066 | break; |
| 1067 | case LLVMContext::MD_fpmath: |
| 1068 | MD = MDNode::getMostGenericFPMath(A: MD, B: IMD); |
| 1069 | break; |
| 1070 | case LLVMContext::MD_noalias: |
| 1071 | case LLVMContext::MD_nontemporal: |
| 1072 | case LLVMContext::MD_invariant_load: |
| 1073 | MD = MDNode::intersect(A: MD, B: IMD); |
| 1074 | break; |
| 1075 | case LLVMContext::MD_access_group: |
| 1076 | MD = intersectAccessGroups(Inst1: Inst, Inst2: IJ); |
| 1077 | break; |
| 1078 | default: |
| 1079 | llvm_unreachable("unhandled metadata" ); |
| 1080 | } |
| 1081 | } |
| 1082 | |
| 1083 | Inst->setMetadata(KindID: Kind, Node: MD); |
| 1084 | } |
| 1085 | |
| 1086 | return Inst; |
| 1087 | } |
| 1088 | |
| 1089 | Constant * |
| 1090 | llvm::createBitMaskForGaps(IRBuilderBase &Builder, unsigned VF, |
| 1091 | const InterleaveGroup<Instruction> &Group) { |
| 1092 | // All 1's means mask is not needed. |
| 1093 | if (Group.getNumMembers() == Group.getFactor()) |
| 1094 | return nullptr; |
| 1095 | |
| 1096 | // TODO: support reversed access. |
| 1097 | assert(!Group.isReverse() && "Reversed group not supported." ); |
| 1098 | |
| 1099 | SmallVector<Constant *, 16> Mask; |
| 1100 | for (unsigned i = 0; i < VF; i++) |
| 1101 | for (unsigned j = 0; j < Group.getFactor(); ++j) { |
| 1102 | unsigned HasMember = Group.getMember(Index: j) ? 1 : 0; |
| 1103 | Mask.push_back(Elt: Builder.getInt1(V: HasMember)); |
| 1104 | } |
| 1105 | |
| 1106 | return ConstantVector::get(V: Mask); |
| 1107 | } |
| 1108 | |
| 1109 | llvm::SmallVector<int, 16> |
| 1110 | llvm::createReplicatedMask(unsigned ReplicationFactor, unsigned VF) { |
| 1111 | SmallVector<int, 16> MaskVec; |
| 1112 | for (unsigned i = 0; i < VF; i++) |
| 1113 | for (unsigned j = 0; j < ReplicationFactor; j++) |
| 1114 | MaskVec.push_back(Elt: i); |
| 1115 | |
| 1116 | return MaskVec; |
| 1117 | } |
| 1118 | |
| 1119 | llvm::SmallVector<int, 16> llvm::createInterleaveMask(unsigned VF, |
| 1120 | unsigned NumVecs) { |
| 1121 | SmallVector<int, 16> Mask; |
| 1122 | for (unsigned i = 0; i < VF; i++) |
| 1123 | for (unsigned j = 0; j < NumVecs; j++) |
| 1124 | Mask.push_back(Elt: j * VF + i); |
| 1125 | |
| 1126 | return Mask; |
| 1127 | } |
| 1128 | |
| 1129 | llvm::SmallVector<int, 16> |
| 1130 | llvm::createStrideMask(unsigned Start, unsigned Stride, unsigned VF) { |
| 1131 | SmallVector<int, 16> Mask; |
| 1132 | for (unsigned i = 0; i < VF; i++) |
| 1133 | Mask.push_back(Elt: Start + i * Stride); |
| 1134 | |
| 1135 | return Mask; |
| 1136 | } |
| 1137 | |
| 1138 | llvm::SmallVector<int, 16> llvm::createSequentialMask(unsigned Start, |
| 1139 | unsigned NumInts, |
| 1140 | unsigned NumUndefs) { |
| 1141 | SmallVector<int, 16> Mask; |
| 1142 | for (unsigned i = 0; i < NumInts; i++) |
| 1143 | Mask.push_back(Elt: Start + i); |
| 1144 | |
| 1145 | for (unsigned i = 0; i < NumUndefs; i++) |
| 1146 | Mask.push_back(Elt: -1); |
| 1147 | |
| 1148 | return Mask; |
| 1149 | } |
| 1150 | |
| 1151 | llvm::SmallVector<int, 16> llvm::createUnaryMask(ArrayRef<int> Mask, |
| 1152 | unsigned NumElts) { |
| 1153 | // Avoid casts in the loop and make sure we have a reasonable number. |
| 1154 | int NumEltsSigned = NumElts; |
| 1155 | assert(NumEltsSigned > 0 && "Expected smaller or non-zero element count" ); |
| 1156 | |
| 1157 | // If the mask chooses an element from operand 1, reduce it to choose from the |
| 1158 | // corresponding element of operand 0. Undef mask elements are unchanged. |
| 1159 | SmallVector<int, 16> UnaryMask; |
| 1160 | for (int MaskElt : Mask) { |
| 1161 | assert((MaskElt < NumEltsSigned * 2) && "Expected valid shuffle mask" ); |
| 1162 | int UnaryElt = MaskElt >= NumEltsSigned ? MaskElt - NumEltsSigned : MaskElt; |
| 1163 | UnaryMask.push_back(Elt: UnaryElt); |
| 1164 | } |
| 1165 | return UnaryMask; |
| 1166 | } |
| 1167 | |
| 1168 | /// A helper function for concatenating vectors. This function concatenates two |
| 1169 | /// vectors having the same element type. If the second vector has fewer |
| 1170 | /// elements than the first, it is padded with undefs. |
| 1171 | static Value *concatenateTwoVectors(IRBuilderBase &Builder, Value *V1, |
| 1172 | Value *V2) { |
| 1173 | VectorType *VecTy1 = dyn_cast<VectorType>(Val: V1->getType()); |
| 1174 | VectorType *VecTy2 = dyn_cast<VectorType>(Val: V2->getType()); |
| 1175 | assert(VecTy1 && VecTy2 && |
| 1176 | VecTy1->getScalarType() == VecTy2->getScalarType() && |
| 1177 | "Expect two vectors with the same element type" ); |
| 1178 | |
| 1179 | unsigned NumElts1 = cast<FixedVectorType>(Val: VecTy1)->getNumElements(); |
| 1180 | unsigned NumElts2 = cast<FixedVectorType>(Val: VecTy2)->getNumElements(); |
| 1181 | assert(NumElts1 >= NumElts2 && "Unexpect the first vector has less elements" ); |
| 1182 | |
| 1183 | if (NumElts1 > NumElts2) { |
| 1184 | // Extend with UNDEFs. |
| 1185 | V2 = Builder.CreateShuffleVector( |
| 1186 | V: V2, Mask: createSequentialMask(Start: 0, NumInts: NumElts2, NumUndefs: NumElts1 - NumElts2)); |
| 1187 | } |
| 1188 | |
| 1189 | return Builder.CreateShuffleVector( |
| 1190 | V1, V2, Mask: createSequentialMask(Start: 0, NumInts: NumElts1 + NumElts2, NumUndefs: 0)); |
| 1191 | } |
| 1192 | |
| 1193 | Value *llvm::concatenateVectors(IRBuilderBase &Builder, |
| 1194 | ArrayRef<Value *> Vecs) { |
| 1195 | unsigned NumVecs = Vecs.size(); |
| 1196 | assert(NumVecs > 1 && "Should be at least two vectors" ); |
| 1197 | |
| 1198 | SmallVector<Value *, 8> ResList; |
| 1199 | ResList.append(in_start: Vecs.begin(), in_end: Vecs.end()); |
| 1200 | do { |
| 1201 | SmallVector<Value *, 8> TmpList; |
| 1202 | for (unsigned i = 0; i < NumVecs - 1; i += 2) { |
| 1203 | Value *V0 = ResList[i], *V1 = ResList[i + 1]; |
| 1204 | assert((V0->getType() == V1->getType() || i == NumVecs - 2) && |
| 1205 | "Only the last vector may have a different type" ); |
| 1206 | |
| 1207 | TmpList.push_back(Elt: concatenateTwoVectors(Builder, V1: V0, V2: V1)); |
| 1208 | } |
| 1209 | |
| 1210 | // Push the last vector if the total number of vectors is odd. |
| 1211 | if (NumVecs % 2 != 0) |
| 1212 | TmpList.push_back(Elt: ResList[NumVecs - 1]); |
| 1213 | |
| 1214 | ResList = TmpList; |
| 1215 | NumVecs = ResList.size(); |
| 1216 | } while (NumVecs > 1); |
| 1217 | |
| 1218 | return ResList[0]; |
| 1219 | } |
| 1220 | |
| 1221 | bool llvm::maskIsAllZeroOrUndef(Value *Mask) { |
| 1222 | assert(isa<VectorType>(Mask->getType()) && |
| 1223 | isa<IntegerType>(Mask->getType()->getScalarType()) && |
| 1224 | cast<IntegerType>(Mask->getType()->getScalarType())->getBitWidth() == |
| 1225 | 1 && |
| 1226 | "Mask must be a vector of i1" ); |
| 1227 | |
| 1228 | auto *ConstMask = dyn_cast<Constant>(Val: Mask); |
| 1229 | if (!ConstMask) |
| 1230 | return false; |
| 1231 | if (ConstMask->isNullValue() || isa<UndefValue>(Val: ConstMask)) |
| 1232 | return true; |
| 1233 | if (isa<ScalableVectorType>(Val: ConstMask->getType())) |
| 1234 | return false; |
| 1235 | for (unsigned |
| 1236 | I = 0, |
| 1237 | E = cast<FixedVectorType>(Val: ConstMask->getType())->getNumElements(); |
| 1238 | I != E; ++I) { |
| 1239 | if (auto *MaskElt = ConstMask->getAggregateElement(Elt: I)) |
| 1240 | if (MaskElt->isNullValue() || isa<UndefValue>(Val: MaskElt)) |
| 1241 | continue; |
| 1242 | return false; |
| 1243 | } |
| 1244 | return true; |
| 1245 | } |
| 1246 | |
| 1247 | bool llvm::maskIsAllOneOrUndef(Value *Mask) { |
| 1248 | assert(isa<VectorType>(Mask->getType()) && |
| 1249 | isa<IntegerType>(Mask->getType()->getScalarType()) && |
| 1250 | cast<IntegerType>(Mask->getType()->getScalarType())->getBitWidth() == |
| 1251 | 1 && |
| 1252 | "Mask must be a vector of i1" ); |
| 1253 | |
| 1254 | auto *ConstMask = dyn_cast<Constant>(Val: Mask); |
| 1255 | if (!ConstMask) |
| 1256 | return false; |
| 1257 | if (ConstMask->isAllOnesValue() || isa<UndefValue>(Val: ConstMask)) |
| 1258 | return true; |
| 1259 | if (isa<ScalableVectorType>(Val: ConstMask->getType())) |
| 1260 | return false; |
| 1261 | for (unsigned |
| 1262 | I = 0, |
| 1263 | E = cast<FixedVectorType>(Val: ConstMask->getType())->getNumElements(); |
| 1264 | I != E; ++I) { |
| 1265 | if (auto *MaskElt = ConstMask->getAggregateElement(Elt: I)) |
| 1266 | if (MaskElt->isAllOnesValue() || isa<UndefValue>(Val: MaskElt)) |
| 1267 | continue; |
| 1268 | return false; |
| 1269 | } |
| 1270 | return true; |
| 1271 | } |
| 1272 | |
| 1273 | bool llvm::maskContainsAllOneOrUndef(Value *Mask) { |
| 1274 | assert(isa<VectorType>(Mask->getType()) && |
| 1275 | isa<IntegerType>(Mask->getType()->getScalarType()) && |
| 1276 | cast<IntegerType>(Mask->getType()->getScalarType())->getBitWidth() == |
| 1277 | 1 && |
| 1278 | "Mask must be a vector of i1" ); |
| 1279 | |
| 1280 | auto *ConstMask = dyn_cast<Constant>(Val: Mask); |
| 1281 | if (!ConstMask) |
| 1282 | return false; |
| 1283 | if (ConstMask->isAllOnesValue() || isa<UndefValue>(Val: ConstMask)) |
| 1284 | return true; |
| 1285 | if (isa<ScalableVectorType>(Val: ConstMask->getType())) |
| 1286 | return false; |
| 1287 | for (unsigned |
| 1288 | I = 0, |
| 1289 | E = cast<FixedVectorType>(Val: ConstMask->getType())->getNumElements(); |
| 1290 | I != E; ++I) { |
| 1291 | if (auto *MaskElt = ConstMask->getAggregateElement(Elt: I)) |
| 1292 | if (MaskElt->isAllOnesValue() || isa<UndefValue>(Val: MaskElt)) |
| 1293 | return true; |
| 1294 | } |
| 1295 | return false; |
| 1296 | } |
| 1297 | |
| 1298 | /// TODO: This is a lot like known bits, but for |
| 1299 | /// vectors. Is there something we can common this with? |
| 1300 | APInt llvm::possiblyDemandedEltsInMask(Value *Mask) { |
| 1301 | assert(isa<FixedVectorType>(Mask->getType()) && |
| 1302 | isa<IntegerType>(Mask->getType()->getScalarType()) && |
| 1303 | cast<IntegerType>(Mask->getType()->getScalarType())->getBitWidth() == |
| 1304 | 1 && |
| 1305 | "Mask must be a fixed width vector of i1" ); |
| 1306 | |
| 1307 | const unsigned VWidth = |
| 1308 | cast<FixedVectorType>(Val: Mask->getType())->getNumElements(); |
| 1309 | APInt DemandedElts = APInt::getAllOnes(numBits: VWidth); |
| 1310 | if (auto *CV = dyn_cast<ConstantVector>(Val: Mask)) |
| 1311 | for (unsigned i = 0; i < VWidth; i++) |
| 1312 | if (CV->getAggregateElement(Elt: i)->isNullValue()) |
| 1313 | DemandedElts.clearBit(BitPosition: i); |
| 1314 | return DemandedElts; |
| 1315 | } |
| 1316 | |
| 1317 | bool InterleavedAccessInfo::isStrided(int Stride) { |
| 1318 | unsigned Factor = std::abs(x: Stride); |
| 1319 | return Factor >= 2 && Factor <= MaxInterleaveGroupFactor; |
| 1320 | } |
| 1321 | |
| 1322 | void InterleavedAccessInfo::collectConstStrideAccesses( |
| 1323 | MapVector<Instruction *, StrideDescriptor> &AccessStrideInfo, |
| 1324 | const DenseMap<Value*, const SCEV*> &Strides) { |
| 1325 | auto &DL = TheLoop->getHeader()->getDataLayout(); |
| 1326 | |
| 1327 | // Since it's desired that the load/store instructions be maintained in |
| 1328 | // "program order" for the interleaved access analysis, we have to visit the |
| 1329 | // blocks in the loop in reverse postorder (i.e., in a topological order). |
| 1330 | // Such an ordering will ensure that any load/store that may be executed |
| 1331 | // before a second load/store will precede the second load/store in |
| 1332 | // AccessStrideInfo. |
| 1333 | LoopBlocksDFS DFS(TheLoop); |
| 1334 | DFS.perform(LI); |
| 1335 | for (BasicBlock *BB : make_range(x: DFS.beginRPO(), y: DFS.endRPO())) |
| 1336 | for (auto &I : *BB) { |
| 1337 | Value *Ptr = getLoadStorePointerOperand(V: &I); |
| 1338 | if (!Ptr) |
| 1339 | continue; |
| 1340 | Type *ElementTy = getLoadStoreType(I: &I); |
| 1341 | |
| 1342 | // Currently, codegen doesn't support cases where the type size doesn't |
| 1343 | // match the alloc size. Skip them for now. |
| 1344 | uint64_t Size = DL.getTypeAllocSize(Ty: ElementTy); |
| 1345 | if (Size * 8 != DL.getTypeSizeInBits(Ty: ElementTy)) |
| 1346 | continue; |
| 1347 | |
| 1348 | // We don't check wrapping here because we don't know yet if Ptr will be |
| 1349 | // part of a full group or a group with gaps. Checking wrapping for all |
| 1350 | // pointers (even those that end up in groups with no gaps) will be overly |
| 1351 | // conservative. For full groups, wrapping should be ok since if we would |
| 1352 | // wrap around the address space we would do a memory access at nullptr |
| 1353 | // even without the transformation. The wrapping checks are therefore |
| 1354 | // deferred until after we've formed the interleaved groups. |
| 1355 | int64_t Stride = |
| 1356 | getPtrStride(PSE, AccessTy: ElementTy, Ptr, Lp: TheLoop, StridesMap: Strides, |
| 1357 | /*Assume=*/true, /*ShouldCheckWrap=*/false).value_or(u: 0); |
| 1358 | |
| 1359 | const SCEV *Scev = replaceSymbolicStrideSCEV(PSE, PtrToStride: Strides, Ptr); |
| 1360 | AccessStrideInfo[&I] = StrideDescriptor(Stride, Scev, Size, |
| 1361 | getLoadStoreAlignment(I: &I)); |
| 1362 | } |
| 1363 | } |
| 1364 | |
| 1365 | // Analyze interleaved accesses and collect them into interleaved load and |
| 1366 | // store groups. |
| 1367 | // |
| 1368 | // When generating code for an interleaved load group, we effectively hoist all |
| 1369 | // loads in the group to the location of the first load in program order. When |
| 1370 | // generating code for an interleaved store group, we sink all stores to the |
| 1371 | // location of the last store. This code motion can change the order of load |
| 1372 | // and store instructions and may break dependences. |
| 1373 | // |
| 1374 | // The code generation strategy mentioned above ensures that we won't violate |
| 1375 | // any write-after-read (WAR) dependences. |
| 1376 | // |
| 1377 | // E.g., for the WAR dependence: a = A[i]; // (1) |
| 1378 | // A[i] = b; // (2) |
| 1379 | // |
| 1380 | // The store group of (2) is always inserted at or below (2), and the load |
| 1381 | // group of (1) is always inserted at or above (1). Thus, the instructions will |
| 1382 | // never be reordered. All other dependences are checked to ensure the |
| 1383 | // correctness of the instruction reordering. |
| 1384 | // |
| 1385 | // The algorithm visits all memory accesses in the loop in bottom-up program |
| 1386 | // order. Program order is established by traversing the blocks in the loop in |
| 1387 | // reverse postorder when collecting the accesses. |
| 1388 | // |
| 1389 | // We visit the memory accesses in bottom-up order because it can simplify the |
| 1390 | // construction of store groups in the presence of write-after-write (WAW) |
| 1391 | // dependences. |
| 1392 | // |
| 1393 | // E.g., for the WAW dependence: A[i] = a; // (1) |
| 1394 | // A[i] = b; // (2) |
| 1395 | // A[i + 1] = c; // (3) |
| 1396 | // |
| 1397 | // We will first create a store group with (3) and (2). (1) can't be added to |
| 1398 | // this group because it and (2) are dependent. However, (1) can be grouped |
| 1399 | // with other accesses that may precede it in program order. Note that a |
| 1400 | // bottom-up order does not imply that WAW dependences should not be checked. |
| 1401 | void InterleavedAccessInfo::analyzeInterleaving( |
| 1402 | bool EnablePredicatedInterleavedMemAccesses) { |
| 1403 | LLVM_DEBUG(dbgs() << "LV: Analyzing interleaved accesses...\n" ); |
| 1404 | const auto &Strides = LAI->getSymbolicStrides(); |
| 1405 | |
| 1406 | // Holds all accesses with a constant stride. |
| 1407 | MapVector<Instruction *, StrideDescriptor> AccessStrideInfo; |
| 1408 | collectConstStrideAccesses(AccessStrideInfo, Strides); |
| 1409 | |
| 1410 | if (AccessStrideInfo.empty()) |
| 1411 | return; |
| 1412 | |
| 1413 | // Collect the dependences in the loop. |
| 1414 | collectDependences(); |
| 1415 | |
| 1416 | // Holds all interleaved store groups temporarily. |
| 1417 | SmallSetVector<InterleaveGroup<Instruction> *, 4> StoreGroups; |
| 1418 | // Holds all interleaved load groups temporarily. |
| 1419 | SmallSetVector<InterleaveGroup<Instruction> *, 4> LoadGroups; |
| 1420 | // Groups added to this set cannot have new members added. |
| 1421 | SmallPtrSet<InterleaveGroup<Instruction> *, 4> CompletedLoadGroups; |
| 1422 | |
| 1423 | // Search in bottom-up program order for pairs of accesses (A and B) that can |
| 1424 | // form interleaved load or store groups. In the algorithm below, access A |
| 1425 | // precedes access B in program order. We initialize a group for B in the |
| 1426 | // outer loop of the algorithm, and then in the inner loop, we attempt to |
| 1427 | // insert each A into B's group if: |
| 1428 | // |
| 1429 | // 1. A and B have the same stride, |
| 1430 | // 2. A and B have the same memory object size, and |
| 1431 | // 3. A belongs in B's group according to its distance from B. |
| 1432 | // |
| 1433 | // Special care is taken to ensure group formation will not break any |
| 1434 | // dependences. |
| 1435 | for (auto BI = AccessStrideInfo.rbegin(), E = AccessStrideInfo.rend(); |
| 1436 | BI != E; ++BI) { |
| 1437 | Instruction *B = BI->first; |
| 1438 | StrideDescriptor DesB = BI->second; |
| 1439 | |
| 1440 | // Initialize a group for B if it has an allowable stride. Even if we don't |
| 1441 | // create a group for B, we continue with the bottom-up algorithm to ensure |
| 1442 | // we don't break any of B's dependences. |
| 1443 | InterleaveGroup<Instruction> *GroupB = nullptr; |
| 1444 | if (isStrided(Stride: DesB.Stride) && |
| 1445 | (!isPredicated(BB: B->getParent()) || EnablePredicatedInterleavedMemAccesses)) { |
| 1446 | GroupB = getInterleaveGroup(Instr: B); |
| 1447 | if (!GroupB) { |
| 1448 | LLVM_DEBUG(dbgs() << "LV: Creating an interleave group with:" << *B |
| 1449 | << '\n'); |
| 1450 | GroupB = createInterleaveGroup(Instr: B, Stride: DesB.Stride, Alignment: DesB.Alignment); |
| 1451 | if (B->mayWriteToMemory()) |
| 1452 | StoreGroups.insert(X: GroupB); |
| 1453 | else |
| 1454 | LoadGroups.insert(X: GroupB); |
| 1455 | } |
| 1456 | } |
| 1457 | |
| 1458 | for (auto AI = std::next(x: BI); AI != E; ++AI) { |
| 1459 | Instruction *A = AI->first; |
| 1460 | StrideDescriptor DesA = AI->second; |
| 1461 | |
| 1462 | // Our code motion strategy implies that we can't have dependences |
| 1463 | // between accesses in an interleaved group and other accesses located |
| 1464 | // between the first and last member of the group. Note that this also |
| 1465 | // means that a group can't have more than one member at a given offset. |
| 1466 | // The accesses in a group can have dependences with other accesses, but |
| 1467 | // we must ensure we don't extend the boundaries of the group such that |
| 1468 | // we encompass those dependent accesses. |
| 1469 | // |
| 1470 | // For example, assume we have the sequence of accesses shown below in a |
| 1471 | // stride-2 loop: |
| 1472 | // |
| 1473 | // (1, 2) is a group | A[i] = a; // (1) |
| 1474 | // | A[i-1] = b; // (2) | |
| 1475 | // A[i-3] = c; // (3) |
| 1476 | // A[i] = d; // (4) | (2, 4) is not a group |
| 1477 | // |
| 1478 | // Because accesses (2) and (3) are dependent, we can group (2) with (1) |
| 1479 | // but not with (4). If we did, the dependent access (3) would be within |
| 1480 | // the boundaries of the (2, 4) group. |
| 1481 | auto DependentMember = [&](InterleaveGroup<Instruction> *Group, |
| 1482 | StrideEntry *A) -> Instruction * { |
| 1483 | for (uint32_t Index = 0; Index < Group->getFactor(); ++Index) { |
| 1484 | Instruction *MemberOfGroupB = Group->getMember(Index); |
| 1485 | if (MemberOfGroupB && !canReorderMemAccessesForInterleavedGroups( |
| 1486 | A, B: &*AccessStrideInfo.find(Key: MemberOfGroupB))) |
| 1487 | return MemberOfGroupB; |
| 1488 | } |
| 1489 | return nullptr; |
| 1490 | }; |
| 1491 | |
| 1492 | auto GroupA = getInterleaveGroup(Instr: A); |
| 1493 | // If A is a load, dependencies are tolerable, there's nothing to do here. |
| 1494 | // If both A and B belong to the same (store) group, they are independent, |
| 1495 | // even if dependencies have not been recorded. |
| 1496 | // If both GroupA and GroupB are null, there's nothing to do here. |
| 1497 | if (A->mayWriteToMemory() && GroupA != GroupB) { |
| 1498 | Instruction *DependentInst = nullptr; |
| 1499 | // If GroupB is a load group, we have to compare AI against all |
| 1500 | // members of GroupB because if any load within GroupB has a dependency |
| 1501 | // on AI, we need to mark GroupB as complete and also release the |
| 1502 | // store GroupA (if A belongs to one). The former prevents incorrect |
| 1503 | // hoisting of load B above store A while the latter prevents incorrect |
| 1504 | // sinking of store A below load B. |
| 1505 | if (GroupB && LoadGroups.contains(key: GroupB)) |
| 1506 | DependentInst = DependentMember(GroupB, &*AI); |
| 1507 | else if (!canReorderMemAccessesForInterleavedGroups(A: &*AI, B: &*BI)) |
| 1508 | DependentInst = B; |
| 1509 | |
| 1510 | if (DependentInst) { |
| 1511 | // A has a store dependence on B (or on some load within GroupB) and |
| 1512 | // is part of a store group. Release A's group to prevent illegal |
| 1513 | // sinking of A below B. A will then be free to form another group |
| 1514 | // with instructions that precede it. |
| 1515 | if (GroupA && StoreGroups.contains(key: GroupA)) { |
| 1516 | LLVM_DEBUG(dbgs() << "LV: Invalidated store group due to " |
| 1517 | "dependence between " |
| 1518 | << *A << " and " << *DependentInst << '\n'); |
| 1519 | StoreGroups.remove(X: GroupA); |
| 1520 | releaseGroup(Group: GroupA); |
| 1521 | } |
| 1522 | // If B is a load and part of an interleave group, no earlier loads |
| 1523 | // can be added to B's interleave group, because this would mean the |
| 1524 | // DependentInst would move across store A. Mark the interleave group |
| 1525 | // as complete. |
| 1526 | if (GroupB && LoadGroups.contains(key: GroupB)) { |
| 1527 | LLVM_DEBUG(dbgs() << "LV: Marking interleave group for " << *B |
| 1528 | << " as complete.\n" ); |
| 1529 | CompletedLoadGroups.insert(Ptr: GroupB); |
| 1530 | } |
| 1531 | } |
| 1532 | } |
| 1533 | if (CompletedLoadGroups.contains(Ptr: GroupB)) { |
| 1534 | // Skip trying to add A to B, continue to look for other conflicting A's |
| 1535 | // in groups to be released. |
| 1536 | continue; |
| 1537 | } |
| 1538 | |
| 1539 | // At this point, we've checked for illegal code motion. If either A or B |
| 1540 | // isn't strided, there's nothing left to do. |
| 1541 | if (!isStrided(Stride: DesA.Stride) || !isStrided(Stride: DesB.Stride)) |
| 1542 | continue; |
| 1543 | |
| 1544 | // Ignore A if it's already in a group or isn't the same kind of memory |
| 1545 | // operation as B. |
| 1546 | // Note that mayReadFromMemory() isn't mutually exclusive to |
| 1547 | // mayWriteToMemory in the case of atomic loads. We shouldn't see those |
| 1548 | // here, canVectorizeMemory() should have returned false - except for the |
| 1549 | // case we asked for optimization remarks. |
| 1550 | if (isInterleaved(Instr: A) || |
| 1551 | (A->mayReadFromMemory() != B->mayReadFromMemory()) || |
| 1552 | (A->mayWriteToMemory() != B->mayWriteToMemory())) |
| 1553 | continue; |
| 1554 | |
| 1555 | // Check rules 1 and 2. Ignore A if its stride or size is different from |
| 1556 | // that of B. |
| 1557 | if (DesA.Stride != DesB.Stride || DesA.Size != DesB.Size) |
| 1558 | continue; |
| 1559 | |
| 1560 | // Ignore A if the memory object of A and B don't belong to the same |
| 1561 | // address space |
| 1562 | if (getLoadStoreAddressSpace(I: A) != getLoadStoreAddressSpace(I: B)) |
| 1563 | continue; |
| 1564 | |
| 1565 | // Calculate the distance from A to B. |
| 1566 | const SCEVConstant *DistToB = dyn_cast<SCEVConstant>( |
| 1567 | Val: PSE.getSE()->getMinusSCEV(LHS: DesA.Scev, RHS: DesB.Scev)); |
| 1568 | if (!DistToB) |
| 1569 | continue; |
| 1570 | int64_t DistanceToB = DistToB->getAPInt().getSExtValue(); |
| 1571 | |
| 1572 | // Check rule 3. Ignore A if its distance to B is not a multiple of the |
| 1573 | // size. |
| 1574 | if (DistanceToB % static_cast<int64_t>(DesB.Size)) |
| 1575 | continue; |
| 1576 | |
| 1577 | // All members of a predicated interleave-group must have the same predicate, |
| 1578 | // and currently must reside in the same BB. |
| 1579 | BasicBlock *BlockA = A->getParent(); |
| 1580 | BasicBlock *BlockB = B->getParent(); |
| 1581 | if ((isPredicated(BB: BlockA) || isPredicated(BB: BlockB)) && |
| 1582 | (!EnablePredicatedInterleavedMemAccesses || BlockA != BlockB)) |
| 1583 | continue; |
| 1584 | |
| 1585 | // The index of A is the index of B plus A's distance to B in multiples |
| 1586 | // of the size. |
| 1587 | int IndexA = |
| 1588 | GroupB->getIndex(Instr: B) + DistanceToB / static_cast<int64_t>(DesB.Size); |
| 1589 | |
| 1590 | // Try to insert A into B's group. |
| 1591 | if (GroupB->insertMember(Instr: A, Index: IndexA, NewAlign: DesA.Alignment)) { |
| 1592 | LLVM_DEBUG(dbgs() << "LV: Inserted:" << *A << '\n' |
| 1593 | << " into the interleave group with" << *B |
| 1594 | << '\n'); |
| 1595 | InterleaveGroupMap[A] = GroupB; |
| 1596 | |
| 1597 | // Set the first load in program order as the insert position. |
| 1598 | if (A->mayReadFromMemory()) |
| 1599 | GroupB->setInsertPos(A); |
| 1600 | } |
| 1601 | } // Iteration over A accesses. |
| 1602 | } // Iteration over B accesses. |
| 1603 | |
| 1604 | auto InvalidateGroupIfMemberMayWrap = [&](InterleaveGroup<Instruction> *Group, |
| 1605 | int Index, |
| 1606 | const char *FirstOrLast) -> bool { |
| 1607 | Instruction *Member = Group->getMember(Index); |
| 1608 | assert(Member && "Group member does not exist" ); |
| 1609 | Value *MemberPtr = getLoadStorePointerOperand(V: Member); |
| 1610 | Type *AccessTy = getLoadStoreType(I: Member); |
| 1611 | if (getPtrStride(PSE, AccessTy, Ptr: MemberPtr, Lp: TheLoop, StridesMap: Strides, |
| 1612 | /*Assume=*/false, /*ShouldCheckWrap=*/true).value_or(u: 0)) |
| 1613 | return false; |
| 1614 | LLVM_DEBUG(dbgs() << "LV: Invalidate candidate interleaved group due to " |
| 1615 | << FirstOrLast |
| 1616 | << " group member potentially pointer-wrapping.\n" ); |
| 1617 | releaseGroup(Group); |
| 1618 | return true; |
| 1619 | }; |
| 1620 | |
| 1621 | // Remove interleaved groups with gaps whose memory |
| 1622 | // accesses may wrap around. We have to revisit the getPtrStride analysis, |
| 1623 | // this time with ShouldCheckWrap=true, since collectConstStrideAccesses does |
| 1624 | // not check wrapping (see documentation there). |
| 1625 | // FORNOW we use Assume=false; |
| 1626 | // TODO: Change to Assume=true but making sure we don't exceed the threshold |
| 1627 | // of runtime SCEV assumptions checks (thereby potentially failing to |
| 1628 | // vectorize altogether). |
| 1629 | // Additional optional optimizations: |
| 1630 | // TODO: If we are peeling the loop and we know that the first pointer doesn't |
| 1631 | // wrap then we can deduce that all pointers in the group don't wrap. |
| 1632 | // This means that we can forcefully peel the loop in order to only have to |
| 1633 | // check the first pointer for no-wrap. When we'll change to use Assume=true |
| 1634 | // we'll only need at most one runtime check per interleaved group. |
| 1635 | for (auto *Group : LoadGroups) { |
| 1636 | // Case 1: A full group. Can Skip the checks; For full groups, if the wide |
| 1637 | // load would wrap around the address space we would do a memory access at |
| 1638 | // nullptr even without the transformation. |
| 1639 | if (Group->getNumMembers() == Group->getFactor()) |
| 1640 | continue; |
| 1641 | |
| 1642 | // Case 2: If first and last members of the group don't wrap this implies |
| 1643 | // that all the pointers in the group don't wrap. |
| 1644 | // So we check only group member 0 (which is always guaranteed to exist), |
| 1645 | // and group member Factor - 1; If the latter doesn't exist we rely on |
| 1646 | // peeling (if it is a non-reversed access -- see Case 3). |
| 1647 | if (InvalidateGroupIfMemberMayWrap(Group, 0, "first" )) |
| 1648 | continue; |
| 1649 | if (Group->getMember(Index: Group->getFactor() - 1)) |
| 1650 | InvalidateGroupIfMemberMayWrap(Group, Group->getFactor() - 1, "last" ); |
| 1651 | else { |
| 1652 | // Case 3: A non-reversed interleaved load group with gaps: We need |
| 1653 | // to execute at least one scalar epilogue iteration. This will ensure |
| 1654 | // we don't speculatively access memory out-of-bounds. We only need |
| 1655 | // to look for a member at index factor - 1, since every group must have |
| 1656 | // a member at index zero. |
| 1657 | if (Group->isReverse()) { |
| 1658 | LLVM_DEBUG( |
| 1659 | dbgs() << "LV: Invalidate candidate interleaved group due to " |
| 1660 | "a reverse access with gaps.\n" ); |
| 1661 | releaseGroup(Group); |
| 1662 | continue; |
| 1663 | } |
| 1664 | LLVM_DEBUG( |
| 1665 | dbgs() << "LV: Interleaved group requires epilogue iteration.\n" ); |
| 1666 | RequiresScalarEpilogue = true; |
| 1667 | } |
| 1668 | } |
| 1669 | |
| 1670 | for (auto *Group : StoreGroups) { |
| 1671 | // Case 1: A full group. Can Skip the checks; For full groups, if the wide |
| 1672 | // store would wrap around the address space we would do a memory access at |
| 1673 | // nullptr even without the transformation. |
| 1674 | if (Group->getNumMembers() == Group->getFactor()) |
| 1675 | continue; |
| 1676 | |
| 1677 | // Interleave-store-group with gaps is implemented using masked wide store. |
| 1678 | // Remove interleaved store groups with gaps if |
| 1679 | // masked-interleaved-accesses are not enabled by the target. |
| 1680 | if (!EnablePredicatedInterleavedMemAccesses) { |
| 1681 | LLVM_DEBUG( |
| 1682 | dbgs() << "LV: Invalidate candidate interleaved store group due " |
| 1683 | "to gaps.\n" ); |
| 1684 | releaseGroup(Group); |
| 1685 | continue; |
| 1686 | } |
| 1687 | |
| 1688 | // Case 2: If first and last members of the group don't wrap this implies |
| 1689 | // that all the pointers in the group don't wrap. |
| 1690 | // So we check only group member 0 (which is always guaranteed to exist), |
| 1691 | // and the last group member. Case 3 (scalar epilog) is not relevant for |
| 1692 | // stores with gaps, which are implemented with masked-store (rather than |
| 1693 | // speculative access, as in loads). |
| 1694 | if (InvalidateGroupIfMemberMayWrap(Group, 0, "first" )) |
| 1695 | continue; |
| 1696 | for (int Index = Group->getFactor() - 1; Index > 0; Index--) |
| 1697 | if (Group->getMember(Index)) { |
| 1698 | InvalidateGroupIfMemberMayWrap(Group, Index, "last" ); |
| 1699 | break; |
| 1700 | } |
| 1701 | } |
| 1702 | } |
| 1703 | |
| 1704 | void InterleavedAccessInfo::invalidateGroupsRequiringScalarEpilogue() { |
| 1705 | // If no group had triggered the requirement to create an epilogue loop, |
| 1706 | // there is nothing to do. |
| 1707 | if (!requiresScalarEpilogue()) |
| 1708 | return; |
| 1709 | |
| 1710 | // Release groups requiring scalar epilogues. Note that this also removes them |
| 1711 | // from InterleaveGroups. |
| 1712 | bool ReleasedGroup = InterleaveGroups.remove_if(P: [&](auto *Group) { |
| 1713 | if (!Group->requiresScalarEpilogue()) |
| 1714 | return false; |
| 1715 | LLVM_DEBUG( |
| 1716 | dbgs() |
| 1717 | << "LV: Invalidate candidate interleaved group due to gaps that " |
| 1718 | "require a scalar epilogue (not allowed under optsize) and cannot " |
| 1719 | "be masked (not enabled). \n" ); |
| 1720 | releaseGroupWithoutRemovingFromSet(Group); |
| 1721 | return true; |
| 1722 | }); |
| 1723 | assert(ReleasedGroup && "At least one group must be invalidated, as a " |
| 1724 | "scalar epilogue was required" ); |
| 1725 | (void)ReleasedGroup; |
| 1726 | RequiresScalarEpilogue = false; |
| 1727 | } |
| 1728 | |
| 1729 | template <typename InstT> |
| 1730 | void InterleaveGroup<InstT>::addMetadata(InstT *NewInst) const { |
| 1731 | llvm_unreachable("addMetadata can only be used for Instruction" ); |
| 1732 | } |
| 1733 | |
| 1734 | namespace llvm { |
| 1735 | template <> |
| 1736 | void InterleaveGroup<Instruction>::addMetadata(Instruction *NewInst) const { |
| 1737 | SmallVector<Value *, 4> VL(make_second_range(c: Members)); |
| 1738 | propagateMetadata(Inst: NewInst, VL); |
| 1739 | } |
| 1740 | } // namespace llvm |
| 1741 | |