lib/CodeGen/GlobalISel/LegalizerInfo.cpp

   1 //===- lib/CodeGen/GlobalISel/LegalizerInfo.cpp - Legalizer ---------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // Implement an interface to specify and query how an illegal operation on a
  11 // given type should be expanded.
  12 //
  13 // Issues to be resolved:
  14 //   + Make it fast.
  15 //   + Support weird types like i3, <7 x i3>, ...
  16 //   + Operations with more than one type (ICMP, CMPXCHG, intrinsics, ...)
  17 //
  18 //===----------------------------------------------------------------------===//
  19
  20 #include "llvm/CodeGen/GlobalISel/LegalizerInfo.h"
  21 #include "llvm/ADT/SmallBitVector.h"
  22 #include "llvm/CodeGen/MachineInstr.h"
  23 #include "llvm/CodeGen/MachineOperand.h"
  24 #include "llvm/CodeGen/MachineRegisterInfo.h"
  25 #include "llvm/CodeGen/TargetOpcodes.h"
  26 #include "llvm/MC/MCInstrDesc.h"
  27 #include "llvm/MC/MCInstrInfo.h"
  28 #include "llvm/Support/Debug.h"
  29 #include "llvm/Support/ErrorHandling.h"
  30 #include "llvm/Support/LowLevelTypeImpl.h"
  31 #include "llvm/Support/MathExtras.h"
  32 #include <algorithm>
  33 #include <map>
  34
  35 using namespace llvm;
  36 using namespace LegalizeActions;
  37
  38 #define DEBUG_TYPE "legalizer-info"
  39
  40 cl::opt<bool> llvm::DisableGISelLegalityCheck(
  41     "disable-gisel-legality-check",
  42     cl::desc("Don't verify that MIR is fully legal between GlobalISel passes"),
  43     cl::Hidden);
  44
  45 raw_ostream &LegalityQuery::print(raw_ostream &OS) const {
  46   OS << Opcode << ", Tys={";
  47   for (const auto &Type : Types) {
  48     OS << Type << ", ";
  49   }
  50   OS << "}, Opcode=";
  51
  52   OS << Opcode << ", MMOs={";
  53   for (const auto &MMODescr : MMODescrs) {
  54     OS << MMODescr.Size << ", ";
  55   }
  56   OS << "}";
  57
  58   return OS;
  59 }
  60
  61 LegalizeActionStep LegalizeRuleSet::apply(const LegalityQuery &Query) const {
  62   LLVM_DEBUG(dbgs() << "Applying legalizer ruleset to: "; Query.print(dbgs());
  63              dbgs() << "\n");
  64   if (Rules.empty()) {
  65     LLVM_DEBUG(dbgs() << ".. fallback to legacy rules (no rules defined)\n");
  66     return {LegalizeAction::UseLegacyRules, 0, LLT{}};
  67   }
  68   for (const auto &Rule : Rules) {
  69     if (Rule.match(Query)) {
  70       LLVM_DEBUG(dbgs() << ".. match\n");
  71       std::pair<unsigned, LLT> Mutation = Rule.determineMutation(Query);
  72       LLVM_DEBUG(dbgs() << ".. .. " << (unsigned)Rule.getAction() << ", "
  73                         << Mutation.first << ", " << Mutation.second << "\n");
  74       assert((Query.Types[Mutation.first] != Mutation.second ||
  75               Rule.getAction() == Lower ||
  76               Rule.getAction() == MoreElements ||
  77               Rule.getAction() == FewerElements) &&
  78              "Simple loop detected");
  79       return {Rule.getAction(), Mutation.first, Mutation.second};
  80     } else
  81       LLVM_DEBUG(dbgs() << ".. no match\n");
  82   }
  83   LLVM_DEBUG(dbgs() << ".. unsupported\n");
  84   return {LegalizeAction::Unsupported, 0, LLT{}};
  85 }
  86
  87 bool LegalizeRuleSet::verifyTypeIdxsCoverage(unsigned NumTypeIdxs) const {
  88 #ifndef NDEBUG
  89   if (Rules.empty()) {
  90     LLVM_DEBUG(
  91         dbgs() << ".. type index coverage check SKIPPED: no rules defined\n");
  92     return true;
  93   }
  94   const int64_t FirstUncovered = TypeIdxsCovered.find_first_unset();
  95   if (FirstUncovered < 0) {
  96     LLVM_DEBUG(dbgs() << ".. type index coverage check SKIPPED:"
  97                          " user-defined predicate detected\n");
  98     return true;
  99   }
 100   const bool AllCovered = (FirstUncovered >= NumTypeIdxs);
 101   LLVM_DEBUG(dbgs() << ".. the first uncovered type index: " << FirstUncovered
 102                     << ", " << (AllCovered ? "OK" : "FAIL") << "\n");
 103   return AllCovered;
 104 #else
 105   return true;
 106 #endif
 107 }
 108
 109 LegalizerInfo::LegalizerInfo() : TablesInitialized(false) {
 110   // Set defaults.
 111   // FIXME: these two (G_ANYEXT and G_TRUNC?) can be legalized to the
 112   // fundamental load/store Jakob proposed. Once loads & stores are supported.
 113   setScalarAction(TargetOpcode::G_ANYEXT, 1, {{1, Legal}});
 114   setScalarAction(TargetOpcode::G_ZEXT, 1, {{1, Legal}});
 115   setScalarAction(TargetOpcode::G_SEXT, 1, {{1, Legal}});
 116   setScalarAction(TargetOpcode::G_TRUNC, 0, {{1, Legal}});
 117   setScalarAction(TargetOpcode::G_TRUNC, 1, {{1, Legal}});
 118
 119   setScalarAction(TargetOpcode::G_INTRINSIC, 0, {{1, Legal}});
 120   setScalarAction(TargetOpcode::G_INTRINSIC_W_SIDE_EFFECTS, 0, {{1, Legal}});
 121
 122   setLegalizeScalarToDifferentSizeStrategy(
 123       TargetOpcode::G_IMPLICIT_DEF, 0, narrowToSmallerAndUnsupportedIfTooSmall);
 124   setLegalizeScalarToDifferentSizeStrategy(
 125       TargetOpcode::G_ADD, 0, widenToLargerTypesAndNarrowToLargest);
 126   setLegalizeScalarToDifferentSizeStrategy(
 127       TargetOpcode::G_OR, 0, widenToLargerTypesAndNarrowToLargest);
 128   setLegalizeScalarToDifferentSizeStrategy(
 129       TargetOpcode::G_LOAD, 0, narrowToSmallerAndUnsupportedIfTooSmall);
 130   setLegalizeScalarToDifferentSizeStrategy(
 131       TargetOpcode::G_STORE, 0, narrowToSmallerAndUnsupportedIfTooSmall);
 132
 133   setLegalizeScalarToDifferentSizeStrategy(
 134       TargetOpcode::G_BRCOND, 0, widenToLargerTypesUnsupportedOtherwise);
 135   setLegalizeScalarToDifferentSizeStrategy(
 136       TargetOpcode::G_INSERT, 0, narrowToSmallerAndUnsupportedIfTooSmall);
 137   setLegalizeScalarToDifferentSizeStrategy(
 138       TargetOpcode::G_EXTRACT, 0, narrowToSmallerAndUnsupportedIfTooSmall);
 139   setLegalizeScalarToDifferentSizeStrategy(
 140       TargetOpcode::G_EXTRACT, 1, narrowToSmallerAndUnsupportedIfTooSmall);
 141   setScalarAction(TargetOpcode::G_FNEG, 0, {{1, Lower}});
 142 }
 143
 144 void LegalizerInfo::computeTables() {
 145   assert(TablesInitialized == false);
 146
 147   for (unsigned OpcodeIdx = 0; OpcodeIdx <= LastOp - FirstOp; ++OpcodeIdx) {
 148     const unsigned Opcode = FirstOp + OpcodeIdx;
 149     for (unsigned TypeIdx = 0; TypeIdx != SpecifiedActions[OpcodeIdx].size();
 150          ++TypeIdx) {
 151       // 0. Collect information specified through the setAction API, i.e.
 152       // for specific bit sizes.
 153       // For scalar types:
 154       SizeAndActionsVec ScalarSpecifiedActions;
 155       // For pointer types:
 156       std::map<uint16_t, SizeAndActionsVec> AddressSpace2SpecifiedActions;
 157       // For vector types:
 158       std::map<uint16_t, SizeAndActionsVec> ElemSize2SpecifiedActions;
 159       for (auto LLT2Action : SpecifiedActions[OpcodeIdx][TypeIdx]) {
 160         const LLT Type = LLT2Action.first;
 161         const LegalizeAction Action = LLT2Action.second;
 162
 163         auto SizeAction = std::make_pair(Type.getSizeInBits(), Action);
 164         if (Type.isPointer())
 165           AddressSpace2SpecifiedActions[Type.getAddressSpace()].push_back(
 166               SizeAction);
 167         else if (Type.isVector())
 168           ElemSize2SpecifiedActions[Type.getElementType().getSizeInBits()]
 169               .push_back(SizeAction);
 170         else
 171           ScalarSpecifiedActions.push_back(SizeAction);
 172       }
 173
 174       // 1. Handle scalar types
 175       {
 176         // Decide how to handle bit sizes for which no explicit specification
 177         // was given.
 178         SizeChangeStrategy S = &unsupportedForDifferentSizes;
 179         if (TypeIdx < ScalarSizeChangeStrategies[OpcodeIdx].size() &&
 180             ScalarSizeChangeStrategies[OpcodeIdx][TypeIdx] != nullptr)
 181           S = ScalarSizeChangeStrategies[OpcodeIdx][TypeIdx];
 182         llvm::sort(ScalarSpecifiedActions.begin(),
 183                    ScalarSpecifiedActions.end());
 184         checkPartialSizeAndActionsVector(ScalarSpecifiedActions);
 185         setScalarAction(Opcode, TypeIdx, S(ScalarSpecifiedActions));
 186       }
 187
 188       // 2. Handle pointer types
 189       for (auto PointerSpecifiedActions : AddressSpace2SpecifiedActions) {
 190         llvm::sort(PointerSpecifiedActions.second.begin(),
 191                    PointerSpecifiedActions.second.end());
 192         checkPartialSizeAndActionsVector(PointerSpecifiedActions.second);
 193         // For pointer types, we assume that there isn't a meaningfull way
 194         // to change the number of bits used in the pointer.
 195         setPointerAction(
 196             Opcode, TypeIdx, PointerSpecifiedActions.first,
 197             unsupportedForDifferentSizes(PointerSpecifiedActions.second));
 198       }
 199
 200       // 3. Handle vector types
 201       SizeAndActionsVec ElementSizesSeen;
 202       for (auto VectorSpecifiedActions : ElemSize2SpecifiedActions) {
 203         llvm::sort(VectorSpecifiedActions.second.begin(),
 204                    VectorSpecifiedActions.second.end());
 205         const uint16_t ElementSize = VectorSpecifiedActions.first;
 206         ElementSizesSeen.push_back({ElementSize, Legal});
 207         checkPartialSizeAndActionsVector(VectorSpecifiedActions.second);
 208         // For vector types, we assume that the best way to adapt the number
 209         // of elements is to the next larger number of elements type for which
 210         // the vector type is legal, unless there is no such type. In that case,
 211         // legalize towards a vector type with a smaller number of elements.
 212         SizeAndActionsVec NumElementsActions;
 213         for (SizeAndAction BitsizeAndAction : VectorSpecifiedActions.second) {
 214           assert(BitsizeAndAction.first % ElementSize == 0);
 215           const uint16_t NumElements = BitsizeAndAction.first / ElementSize;
 216           NumElementsActions.push_back({NumElements, BitsizeAndAction.second});
 217         }
 218         setVectorNumElementAction(
 219             Opcode, TypeIdx, ElementSize,
 220             moreToWiderTypesAndLessToWidest(NumElementsActions));
 221       }
 222       llvm::sort(ElementSizesSeen);
 223       SizeChangeStrategy VectorElementSizeChangeStrategy =
 224           &unsupportedForDifferentSizes;
 225       if (TypeIdx < VectorElementSizeChangeStrategies[OpcodeIdx].size() &&
 226           VectorElementSizeChangeStrategies[OpcodeIdx][TypeIdx] != nullptr)
 227         VectorElementSizeChangeStrategy =
 228             VectorElementSizeChangeStrategies[OpcodeIdx][TypeIdx];
 229       setScalarInVectorAction(
 230           Opcode, TypeIdx, VectorElementSizeChangeStrategy(ElementSizesSeen));
 231     }
 232   }
 233
 234   TablesInitialized = true;
 235 }
 236
 237 // FIXME: inefficient implementation for now. Without ComputeValueVTs we're
 238 // probably going to need specialized lookup structures for various types before
 239 // we have any hope of doing well with something like <13 x i3>. Even the common
 240 // cases should do better than what we have now.
 241 std::pair<LegalizeAction, LLT>
 242 LegalizerInfo::getAspectAction(const InstrAspect &Aspect) const {
 243   assert(TablesInitialized && "backend forgot to call computeTables");
 244   // These *have* to be implemented for now, they're the fundamental basis of
 245   // how everything else is transformed.
 246   if (Aspect.Type.isScalar() || Aspect.Type.isPointer())
 247     return findScalarLegalAction(Aspect);
 248   assert(Aspect.Type.isVector());
 249   return findVectorLegalAction(Aspect);
 250 }
 251
 252 /// Helper function to get LLT for the given type index.
 253 static LLT getTypeFromTypeIdx(const MachineInstr &MI,
 254                               const MachineRegisterInfo &MRI, unsigned OpIdx,
 255                               unsigned TypeIdx) {
 256   assert(TypeIdx < MI.getNumOperands() && "Unexpected TypeIdx");
 257   // G_UNMERGE_VALUES has variable number of operands, but there is only
 258   // one source type and one destination type as all destinations must be the
 259   // same type. So, get the last operand if TypeIdx == 1.
 260   if (MI.getOpcode() == TargetOpcode::G_UNMERGE_VALUES && TypeIdx == 1)
 261     return MRI.getType(MI.getOperand(MI.getNumOperands() - 1).getReg());
 262   return MRI.getType(MI.getOperand(OpIdx).getReg());
 263 }
 264
 265 unsigned LegalizerInfo::getOpcodeIdxForOpcode(unsigned Opcode) const {
 266   assert(Opcode >= FirstOp && Opcode <= LastOp && "Unsupported opcode");
 267   return Opcode - FirstOp;
 268 }
 269
 270 unsigned LegalizerInfo::getActionDefinitionsIdx(unsigned Opcode) const {
 271   unsigned OpcodeIdx = getOpcodeIdxForOpcode(Opcode);
 272   if (unsigned Alias = RulesForOpcode[OpcodeIdx].getAlias()) {
 273     LLVM_DEBUG(dbgs() << ".. opcode " << Opcode << " is aliased to " << Alias
 274                       << "\n");
 275     OpcodeIdx = getOpcodeIdxForOpcode(Alias);
 276     LLVM_DEBUG(dbgs() << ".. opcode " << Alias << " is aliased to "
 277                       << RulesForOpcode[OpcodeIdx].getAlias() << "\n");
 278     assert(RulesForOpcode[OpcodeIdx].getAlias() == 0 && "Cannot chain aliases");
 279   }
 280
 281   return OpcodeIdx;
 282 }
 283
 284 const LegalizeRuleSet &
 285 LegalizerInfo::getActionDefinitions(unsigned Opcode) const {
 286   unsigned OpcodeIdx = getActionDefinitionsIdx(Opcode);
 287   return RulesForOpcode[OpcodeIdx];
 288 }
 289
 290 LegalizeRuleSet &LegalizerInfo::getActionDefinitionsBuilder(unsigned Opcode) {
 291   unsigned OpcodeIdx = getActionDefinitionsIdx(Opcode);
 292   auto &Result = RulesForOpcode[OpcodeIdx];
 293   assert(!Result.isAliasedByAnother() && "Modifying this opcode will modify aliases");
 294   return Result;
 295 }
 296
 297 LegalizeRuleSet &LegalizerInfo::getActionDefinitionsBuilder(
 298     std::initializer_list<unsigned> Opcodes) {
 299   unsigned Representative = *Opcodes.begin();
 300
 301   assert(Opcodes.begin() != Opcodes.end() &&
 302          Opcodes.begin() + 1 != Opcodes.end() &&
 303          "Initializer list must have at least two opcodes");
 304
 305   for (auto I = Opcodes.begin() + 1, E = Opcodes.end(); I != E; ++I)
 306     aliasActionDefinitions(Representative, *I);
 307
 308   auto &Return = getActionDefinitionsBuilder(Representative);
 309   Return.setIsAliasedByAnother();
 310   return Return;
 311 }
 312
 313 void LegalizerInfo::aliasActionDefinitions(unsigned OpcodeTo,
 314                                            unsigned OpcodeFrom) {
 315   assert(OpcodeTo != OpcodeFrom && "Cannot alias to self");
 316   assert(OpcodeTo >= FirstOp && OpcodeTo <= LastOp && "Unsupported opcode");
 317   const unsigned OpcodeFromIdx = getOpcodeIdxForOpcode(OpcodeFrom);
 318   RulesForOpcode[OpcodeFromIdx].aliasTo(OpcodeTo);
 319 }
 320
 321 LegalizeActionStep
 322 LegalizerInfo::getAction(const LegalityQuery &Query) const {
 323   LegalizeActionStep Step = getActionDefinitions(Query.Opcode).apply(Query);
 324   if (Step.Action != LegalizeAction::UseLegacyRules) {
 325     return Step;
 326   }
 327
 328   for (unsigned i = 0; i < Query.Types.size(); ++i) {
 329     auto Action = getAspectAction({Query.Opcode, i, Query.Types[i]});
 330     if (Action.first != Legal) {
 331       LLVM_DEBUG(dbgs() << ".. (legacy) Type " << i
 332                         << " Action=" << (unsigned)Action.first << ", "
 333                         << Action.second << "\n");
 334       return {Action.first, i, Action.second};
 335     } else
 336       LLVM_DEBUG(dbgs() << ".. (legacy) Type " << i << " Legal\n");
 337   }
 338   LLVM_DEBUG(dbgs() << ".. (legacy) Legal\n");
 339   return {Legal, 0, LLT{}};
 340 }
 341
 342 LegalizeActionStep
 343 LegalizerInfo::getAction(const MachineInstr &MI,
 344                          const MachineRegisterInfo &MRI) const {
 345   SmallVector<LLT, 2> Types;
 346   SmallBitVector SeenTypes(8);
 347   const MCOperandInfo *OpInfo = MI.getDesc().OpInfo;
 348   // FIXME: probably we'll need to cache the results here somehow?
 349   for (unsigned i = 0; i < MI.getDesc().getNumOperands(); ++i) {
 350     if (!OpInfo[i].isGenericType())
 351       continue;
 352
 353     // We must only record actions once for each TypeIdx; otherwise we'd
 354     // try to legalize operands multiple times down the line.
 355     unsigned TypeIdx = OpInfo[i].getGenericTypeIndex();
 356     if (SeenTypes[TypeIdx])
 357       continue;
 358
 359     SeenTypes.set(TypeIdx);
 360
 361     LLT Ty = getTypeFromTypeIdx(MI, MRI, i, TypeIdx);
 362     Types.push_back(Ty);
 363   }
 364
 365   SmallVector<LegalityQuery::MemDesc, 2> MemDescrs;
 366   for (const auto &MMO : MI.memoperands())
 367     MemDescrs.push_back(
 368         {MMO->getSize() /* in bytes */ * 8, MMO->getOrdering()});
 369
 370   return getAction({MI.getOpcode(), Types, MemDescrs});
 371 }
 372
 373 bool LegalizerInfo::isLegal(const MachineInstr &MI,
 374                             const MachineRegisterInfo &MRI) const {
 375   return getAction(MI, MRI).Action == Legal;
 376 }
 377
 378 bool LegalizerInfo::legalizeCustom(MachineInstr &MI, MachineRegisterInfo &MRI,
 379                                    MachineIRBuilder &MIRBuilder) const {
 380   return false;
 381 }
 382
 383 LegalizerInfo::SizeAndActionsVec
 384 LegalizerInfo::increaseToLargerTypesAndDecreaseToLargest(
 385     const SizeAndActionsVec &v, LegalizeAction IncreaseAction,
 386     LegalizeAction DecreaseAction) {
 387   SizeAndActionsVec result;
 388   unsigned LargestSizeSoFar = 0;
 389   if (v.size() >= 1 && v[0].first != 1)
 390     result.push_back({1, IncreaseAction});
 391   for (size_t i = 0; i < v.size(); ++i) {
 392     result.push_back(v[i]);
 393     LargestSizeSoFar = v[i].first;
 394     if (i + 1 < v.size() && v[i + 1].first != v[i].first + 1) {
 395       result.push_back({LargestSizeSoFar + 1, IncreaseAction});
 396       LargestSizeSoFar = v[i].first + 1;
 397     }
 398   }
 399   result.push_back({LargestSizeSoFar + 1, DecreaseAction});
 400   return result;
 401 }
 402
 403 LegalizerInfo::SizeAndActionsVec
 404 LegalizerInfo::decreaseToSmallerTypesAndIncreaseToSmallest(
 405     const SizeAndActionsVec &v, LegalizeAction DecreaseAction,
 406     LegalizeAction IncreaseAction) {
 407   SizeAndActionsVec result;
 408   if (v.size() == 0 || v[0].first != 1)
 409     result.push_back({1, IncreaseAction});
 410   for (size_t i = 0; i < v.size(); ++i) {
 411     result.push_back(v[i]);
 412     if (i + 1 == v.size() || v[i + 1].first != v[i].first + 1) {
 413       result.push_back({v[i].first + 1, DecreaseAction});
 414     }
 415   }
 416   return result;
 417 }
 418
 419 LegalizerInfo::SizeAndAction
 420 LegalizerInfo::findAction(const SizeAndActionsVec &Vec, const uint32_t Size) {
 421   assert(Size >= 1);
 422   // Find the last element in Vec that has a bitsize equal to or smaller than
 423   // the requested bit size.
 424   // That is the element just before the first element that is bigger than Size.
 425   auto VecIt = std::upper_bound(
 426       Vec.begin(), Vec.end(), Size,
 427       [](const uint32_t Size, const SizeAndAction lhs) -> bool {
 428         return Size < lhs.first;
 429       });
 430   assert(VecIt != Vec.begin() && "Does Vec not start with size 1?");
 431   --VecIt;
 432   int VecIdx = VecIt - Vec.begin();
 433
 434   LegalizeAction Action = Vec[VecIdx].second;
 435   switch (Action) {
 436   case Legal:
 437   case Lower:
 438   case Libcall:
 439   case Custom:
 440     return {Size, Action};
 441   case FewerElements:
 442     // FIXME: is this special case still needed and correct?
 443     // Special case for scalarization:
 444     if (Vec == SizeAndActionsVec({{1, FewerElements}}))
 445       return {1, FewerElements};
 446     LLVM_FALLTHROUGH;
 447   case NarrowScalar: {
 448     // The following needs to be a loop, as for now, we do allow needing to
 449     // go over "Unsupported" bit sizes before finding a legalizable bit size.
 450     // e.g. (s8, WidenScalar), (s9, Unsupported), (s32, Legal). if Size==8,
 451     // we need to iterate over s9, and then to s32 to return (s32, Legal).
 452     // If we want to get rid of the below loop, we should have stronger asserts
 453     // when building the SizeAndActionsVecs, probably not allowing
 454     // "Unsupported" unless at the ends of the vector.
 455     for (int i = VecIdx - 1; i >= 0; --i)
 456       if (!needsLegalizingToDifferentSize(Vec[i].second) &&
 457           Vec[i].second != Unsupported)
 458         return {Vec[i].first, Action};
 459     llvm_unreachable("");
 460   }
 461   case WidenScalar:
 462   case MoreElements: {
 463     // See above, the following needs to be a loop, at least for now.
 464     for (std::size_t i = VecIdx + 1; i < Vec.size(); ++i)
 465       if (!needsLegalizingToDifferentSize(Vec[i].second) &&
 466           Vec[i].second != Unsupported)
 467         return {Vec[i].first, Action};
 468     llvm_unreachable("");
 469   }
 470   case Unsupported:
 471     return {Size, Unsupported};
 472   case NotFound:
 473   case UseLegacyRules:
 474     llvm_unreachable("NotFound");
 475   }
 476   llvm_unreachable("Action has an unknown enum value");
 477 }
 478
 479 std::pair<LegalizeAction, LLT>
 480 LegalizerInfo::findScalarLegalAction(const InstrAspect &Aspect) const {
 481   assert(Aspect.Type.isScalar() || Aspect.Type.isPointer());
 482   if (Aspect.Opcode < FirstOp || Aspect.Opcode > LastOp)
 483     return {NotFound, LLT()};
 484   const unsigned OpcodeIdx = getOpcodeIdxForOpcode(Aspect.Opcode);
 485   if (Aspect.Type.isPointer() &&
 486       AddrSpace2PointerActions[OpcodeIdx].find(Aspect.Type.getAddressSpace()) ==
 487           AddrSpace2PointerActions[OpcodeIdx].end()) {
 488     return {NotFound, LLT()};
 489   }
 490   const SmallVector<SizeAndActionsVec, 1> &Actions =
 491       Aspect.Type.isPointer()
 492           ? AddrSpace2PointerActions[OpcodeIdx]
 493                 .find(Aspect.Type.getAddressSpace())
 494                 ->second
 495           : ScalarActions[OpcodeIdx];
 496   if (Aspect.Idx >= Actions.size())
 497     return {NotFound, LLT()};
 498   const SizeAndActionsVec &Vec = Actions[Aspect.Idx];
 499   // FIXME: speed up this search, e.g. by using a results cache for repeated
 500   // queries?
 501   auto SizeAndAction = findAction(Vec, Aspect.Type.getSizeInBits());
 502   return {SizeAndAction.second,
 503           Aspect.Type.isScalar() ? LLT::scalar(SizeAndAction.first)
 504                                  : LLT::pointer(Aspect.Type.getAddressSpace(),
 505                                                 SizeAndAction.first)};
 506 }
 507
 508 std::pair<LegalizeAction, LLT>
 509 LegalizerInfo::findVectorLegalAction(const InstrAspect &Aspect) const {
 510   assert(Aspect.Type.isVector());
 511   // First legalize the vector element size, then legalize the number of
 512   // lanes in the vector.
 513   if (Aspect.Opcode < FirstOp || Aspect.Opcode > LastOp)
 514     return {NotFound, Aspect.Type};
 515   const unsigned OpcodeIdx = getOpcodeIdxForOpcode(Aspect.Opcode);
 516   const unsigned TypeIdx = Aspect.Idx;
 517   if (TypeIdx >= ScalarInVectorActions[OpcodeIdx].size())
 518     return {NotFound, Aspect.Type};
 519   const SizeAndActionsVec &ElemSizeVec =
 520       ScalarInVectorActions[OpcodeIdx][TypeIdx];
 521
 522   LLT IntermediateType;
 523   auto ElementSizeAndAction =
 524       findAction(ElemSizeVec, Aspect.Type.getScalarSizeInBits());
 525   IntermediateType =
 526       LLT::vector(Aspect.Type.getNumElements(), ElementSizeAndAction.first);
 527   if (ElementSizeAndAction.second != Legal)
 528     return {ElementSizeAndAction.second, IntermediateType};
 529
 530   auto i = NumElements2Actions[OpcodeIdx].find(
 531       IntermediateType.getScalarSizeInBits());
 532   if (i == NumElements2Actions[OpcodeIdx].end()) {
 533     return {NotFound, IntermediateType};
 534   }
 535   const SizeAndActionsVec &NumElementsVec = (*i).second[TypeIdx];
 536   auto NumElementsAndAction =
 537       findAction(NumElementsVec, IntermediateType.getNumElements());
 538   return {NumElementsAndAction.second,
 539           LLT::vector(NumElementsAndAction.first,
 540                       IntermediateType.getScalarSizeInBits())};
 541 }
 542
 543 /// \pre Type indices of every opcode form a dense set starting from 0.
 544 void LegalizerInfo::verify(const MCInstrInfo &MII) const {
 545 #ifndef NDEBUG
 546   std::vector<unsigned> FailedOpcodes;
 547   for (unsigned Opcode = FirstOp; Opcode <= LastOp; ++Opcode) {
 548     const MCInstrDesc &MCID = MII.get(Opcode);
 549     const unsigned NumTypeIdxs = std::accumulate(
 550         MCID.opInfo_begin(), MCID.opInfo_end(), 0U,
 551         [](unsigned Acc, const MCOperandInfo &OpInfo) {
 552           return OpInfo.isGenericType()
 553                      ? std::max(OpInfo.getGenericTypeIndex() + 1U, Acc)
 554                      : Acc;
 555         });
 556     LLVM_DEBUG(dbgs() << MII.getName(Opcode) << " (opcode " << Opcode
 557                       << "): " << NumTypeIdxs << " type ind"
 558                       << (NumTypeIdxs == 1 ? "ex" : "ices") << "\n");
 559     const LegalizeRuleSet &RuleSet = getActionDefinitions(Opcode);
 560     if (!RuleSet.verifyTypeIdxsCoverage(NumTypeIdxs))
 561       FailedOpcodes.push_back(Opcode);
 562   }
 563   if (!FailedOpcodes.empty()) {
 564     errs() << "The following opcodes have ill-defined legalization rules:";
 565     for (unsigned Opcode : FailedOpcodes)
 566       errs() << " " << MII.getName(Opcode);
 567     errs() << "\n";
 568
 569     report_fatal_error("ill-defined LegalizerInfo"
 570                        ", try -debug-only=legalizer-info for details");
 571   }
 572 #endif
 573 }
 574
 575 #ifndef NDEBUG
 576 // FIXME: This should be in the MachineVerifier, but it can't use the
 577 // LegalizerInfo as it's currently in the separate GlobalISel library.
 578 // Note that RegBankSelected property already checked in the verifier
 579 // has the same layering problem, but we only use inline methods so
 580 // end up not needing to link against the GlobalISel library.
 581 const MachineInstr *llvm::machineFunctionIsIllegal(const MachineFunction &MF) {
 582   if (const LegalizerInfo *MLI = MF.getSubtarget().getLegalizerInfo()) {
 583     const MachineRegisterInfo &MRI = MF.getRegInfo();
 584     for (const MachineBasicBlock &MBB : MF)
 585       for (const MachineInstr &MI : MBB)
 586         if (isPreISelGenericOpcode(MI.getOpcode()) && !MLI->isLegal(MI, MRI))
 587           return &MI;
 588   }
 589   return nullptr;
 590 }
 591 #endif