llvm/lib/MC/MCSubtargetInfo.cpp - llvm-project - Git at Google

 //===- MCSubtargetInfo.cpp - Subtarget Information ------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//

 #include "llvm/MC/MCSubtargetInfo.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/MC/MCInstrItineraries.h"
 #include "llvm/MC/MCSchedule.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/TargetParser/SubtargetFeature.h"
 #include <algorithm>
 #include <cassert>
 #include <cstring>
 #include <optional>

 using namespace llvm;

 /// Find KV in array using binary search.
 template <typename T>
 static const T *Find(StringRef S, ArrayRef<T> A) {
   // Binary search the array
   auto F = llvm::lower_bound(A, S);
   // If not found then return NULL
   if (F == A.end() || StringRef(F->Key) != S) return nullptr;
   // Return the found array item
   return F;
 }

 /// For each feature that is (transitively) implied by this feature, set it.
 static
 void SetImpliedBits(FeatureBitset &Bits, const FeatureBitset &Implies,
                     ArrayRef<SubtargetFeatureKV> FeatureTable) {
   // OR the Implies bits in outside the loop. This allows the Implies for CPUs
   // which might imply features not in FeatureTable to use this.
   Bits |= Implies;
   for (const SubtargetFeatureKV &FE : FeatureTable)
     if (Implies.test(FE.Value))
       SetImpliedBits(Bits, FE.Implies.getAsBitset(), FeatureTable);
 }

 /// For each feature that (transitively) implies this feature, clear it.
 static
 void ClearImpliedBits(FeatureBitset &Bits, unsigned Value,
                       ArrayRef<SubtargetFeatureKV> FeatureTable) {
   for (const SubtargetFeatureKV &FE : FeatureTable) {
     if (FE.Implies.getAsBitset().test(Value)) {
       Bits.reset(FE.Value);
       ClearImpliedBits(Bits, FE.Value, FeatureTable);
     }
   }
 }

 static void ApplyFeatureFlag(FeatureBitset &Bits, StringRef Feature,
                              ArrayRef<SubtargetFeatureKV> FeatureTable) {
   assert(SubtargetFeatures::hasFlag(Feature) &&
          "Feature flags should start with '+' or '-'");

   // Find feature in table.
   const SubtargetFeatureKV *FeatureEntry =
       Find(SubtargetFeatures::StripFlag(Feature), FeatureTable);
   // If there is a match
   if (FeatureEntry) {
     // Enable/disable feature in bits
     if (SubtargetFeatures::isEnabled(Feature)) {
       Bits.set(FeatureEntry->Value);

       // For each feature that this implies, set it.
       SetImpliedBits(Bits, FeatureEntry->Implies.getAsBitset(), FeatureTable);
     } else {
       Bits.reset(FeatureEntry->Value);

       // For each feature that implies this, clear it.
       ClearImpliedBits(Bits, FeatureEntry->Value, FeatureTable);
     }
   } else {
     errs() << "'" << Feature << "' is not a recognized feature for this target"
            << " (ignoring feature)\n";
   }
 }

 /// Return the length of the longest entry in the table.
 template <typename T>
 static size_t getLongestEntryLength(ArrayRef<T> Table) {
   size_t MaxLen = 0;
   for (auto &I : Table)
     MaxLen = std::max(MaxLen, std::strlen(I.Key));
   return MaxLen;
 }

 /// Display help for feature and mcpu choices.
 static void Help(ArrayRef<SubtargetSubTypeKV> CPUTable,
                  ArrayRef<SubtargetFeatureKV> FeatTable) {
   // the static variable ensures that the help information only gets
   // printed once even though a target machine creates multiple subtargets
   static bool PrintOnce = false;
   if (PrintOnce) {
     return;
   }

   // Determine the length of the longest CPU and Feature entries.
   unsigned MaxCPULen  = getLongestEntryLength(CPUTable);
   unsigned MaxFeatLen = getLongestEntryLength(FeatTable);

   // Print the CPU table.
   errs() << "Available CPUs for this target:\n\n";
   for (auto &CPU : CPUTable)
     errs() << format("  %-*s - Select the %s processor.\n", MaxCPULen, CPU.Key,
                      CPU.Key);
   errs() << '\n';

   // Print the Feature table.
   errs() << "Available features for this target:\n\n";
   for (auto &Feature : FeatTable)
     errs() << format("  %-*s - %s.\n", MaxFeatLen, Feature.Key, Feature.Desc);
   errs() << '\n';

   errs() << "Use +feature to enable a feature, or -feature to disable it.\n"
             "For example, llc -mcpu=mycpu -mattr=+feature1,-feature2\n";

   PrintOnce = true;
 }

 /// Display help for mcpu choices only
 static void cpuHelp(ArrayRef<SubtargetSubTypeKV> CPUTable) {
   // the static variable ensures that the help information only gets
   // printed once even though a target machine creates multiple subtargets
   static bool PrintOnce = false;
   if (PrintOnce) {
     return;
   }

   // Print the CPU table.
   errs() << "Available CPUs for this target:\n\n";
   for (auto &CPU : CPUTable)
     errs() << "\t" << CPU.Key << "\n";
   errs() << '\n';

   errs() << "Use -mcpu or -mtune to specify the target's processor.\n"
             "For example, clang --target=aarch64-unknown-linux-gnu "
             "-mcpu=cortex-a35\n";

   PrintOnce = true;
 }

 static FeatureBitset getFeatures(StringRef CPU, StringRef TuneCPU, StringRef FS,
                                  ArrayRef<SubtargetSubTypeKV> ProcDesc,
                                  ArrayRef<SubtargetFeatureKV> ProcFeatures) {
   SubtargetFeatures Features(FS);

   if (ProcDesc.empty() || ProcFeatures.empty())
     return FeatureBitset();

   assert(llvm::is_sorted(ProcDesc) && "CPU table is not sorted");
   assert(llvm::is_sorted(ProcFeatures) && "CPU features table is not sorted");
   // Resulting bits
   FeatureBitset Bits;

   // Check if help is needed
   if (CPU == "help")
     Help(ProcDesc, ProcFeatures);

   // Find CPU entry if CPU name is specified.
   else if (!CPU.empty()) {
     const SubtargetSubTypeKV *CPUEntry = Find(CPU, ProcDesc);

     // If there is a match
     if (CPUEntry) {
       // Set the features implied by this CPU feature, if any.
       SetImpliedBits(Bits, CPUEntry->Implies.getAsBitset(), ProcFeatures);
     } else {
       errs() << "'" << CPU << "' is not a recognized processor for this target"
              << " (ignoring processor)\n";
     }
   }

   if (!TuneCPU.empty()) {
     const SubtargetSubTypeKV *CPUEntry = Find(TuneCPU, ProcDesc);

     // If there is a match
     if (CPUEntry) {
       // Set the features implied by this CPU feature, if any.
       SetImpliedBits(Bits, CPUEntry->TuneImplies.getAsBitset(), ProcFeatures);
     } else if (TuneCPU != CPU) {
       errs() << "'" << TuneCPU << "' is not a recognized processor for this "
              << "target (ignoring processor)\n";
     }
   }

   // Iterate through each feature
   for (const std::string &Feature : Features.getFeatures()) {
     // Check for help
     if (Feature == "+help")
       Help(ProcDesc, ProcFeatures);
     else if (Feature == "+cpuhelp")
       cpuHelp(ProcDesc);
     else
       ApplyFeatureFlag(Bits, Feature, ProcFeatures);
   }

   return Bits;
 }

 void MCSubtargetInfo::InitMCProcessorInfo(StringRef CPU, StringRef TuneCPU,
                                           StringRef FS) {
   FeatureBits = getFeatures(CPU, TuneCPU, FS, ProcDesc, ProcFeatures);
   FeatureString = std::string(FS);

   if (!TuneCPU.empty())
     CPUSchedModel = &getSchedModelForCPU(TuneCPU);
   else
     CPUSchedModel = &MCSchedModel::Default;
 }

 void MCSubtargetInfo::setDefaultFeatures(StringRef CPU, StringRef TuneCPU,
                                          StringRef FS) {
   FeatureBits = getFeatures(CPU, TuneCPU, FS, ProcDesc, ProcFeatures);
   FeatureString = std::string(FS);
 }

 MCSubtargetInfo::MCSubtargetInfo(const Triple &TT, StringRef C, StringRef TC,
                                  StringRef FS, ArrayRef<SubtargetFeatureKV> PF,
                                  ArrayRef<SubtargetSubTypeKV> PD,
                                  const MCWriteProcResEntry *WPR,
                                  const MCWriteLatencyEntry *WL,
                                  const MCReadAdvanceEntry *RA,
                                  const InstrStage *IS, const unsigned *OC,
                                  const unsigned *FP)
     : TargetTriple(TT), CPU(std::string(C)), TuneCPU(std::string(TC)),
       ProcFeatures(PF), ProcDesc(PD), WriteProcResTable(WPR),
       WriteLatencyTable(WL), ReadAdvanceTable(RA), Stages(IS),
       OperandCycles(OC), ForwardingPaths(FP) {
   InitMCProcessorInfo(CPU, TuneCPU, FS);
 }

 FeatureBitset MCSubtargetInfo::ToggleFeature(uint64_t FB) {
   FeatureBits.flip(FB);
   return FeatureBits;
 }

 FeatureBitset MCSubtargetInfo::ToggleFeature(const FeatureBitset &FB) {
   FeatureBits ^= FB;
   return FeatureBits;
 }

 FeatureBitset MCSubtargetInfo::SetFeatureBitsTransitively(
   const FeatureBitset &FB) {
   SetImpliedBits(FeatureBits, FB, ProcFeatures);
   return FeatureBits;
 }

 FeatureBitset MCSubtargetInfo::ClearFeatureBitsTransitively(
   const FeatureBitset &FB) {
   for (unsigned I = 0, E = FB.size(); I < E; I++) {
     if (FB[I]) {
       FeatureBits.reset(I);
       ClearImpliedBits(FeatureBits, I, ProcFeatures);
     }
   }
   return FeatureBits;
 }

 FeatureBitset MCSubtargetInfo::ToggleFeature(StringRef Feature) {
   // Find feature in table.
   const SubtargetFeatureKV *FeatureEntry =
       Find(SubtargetFeatures::StripFlag(Feature), ProcFeatures);
   // If there is a match
   if (FeatureEntry) {
     if (FeatureBits.test(FeatureEntry->Value)) {
       FeatureBits.reset(FeatureEntry->Value);
       // For each feature that implies this, clear it.
       ClearImpliedBits(FeatureBits, FeatureEntry->Value, ProcFeatures);
     } else {
       FeatureBits.set(FeatureEntry->Value);

       // For each feature that this implies, set it.
       SetImpliedBits(FeatureBits, FeatureEntry->Implies.getAsBitset(),
                      ProcFeatures);
     }
   } else {
     errs() << "'" << Feature << "' is not a recognized feature for this target"
            << " (ignoring feature)\n";
   }

   return FeatureBits;
 }

 FeatureBitset MCSubtargetInfo::ApplyFeatureFlag(StringRef FS) {
   ::ApplyFeatureFlag(FeatureBits, FS, ProcFeatures);
   return FeatureBits;
 }

 bool MCSubtargetInfo::checkFeatures(StringRef FS) const {
   SubtargetFeatures T(FS);
   FeatureBitset Set, All;
   for (std::string F : T.getFeatures()) {
     ::ApplyFeatureFlag(Set, F, ProcFeatures);
     if (F[0] == '-')
       F[0] = '+';
     ::ApplyFeatureFlag(All, F, ProcFeatures);
   }
   return (FeatureBits & All) == Set;
 }

 const MCSchedModel &MCSubtargetInfo::getSchedModelForCPU(StringRef CPU) const {
   assert(llvm::is_sorted(ProcDesc) &&
          "Processor machine model table is not sorted");

   // Find entry
   const SubtargetSubTypeKV *CPUEntry = Find(CPU, ProcDesc);

   if (!CPUEntry) {
     if (CPU != "help") // Don't error if the user asked for help.
       errs() << "'" << CPU
              << "' is not a recognized processor for this target"
              << " (ignoring processor)\n";
     return MCSchedModel::Default;
   }
   assert(CPUEntry->SchedModel && "Missing processor SchedModel value");
   return *CPUEntry->SchedModel;
 }

 InstrItineraryData
 MCSubtargetInfo::getInstrItineraryForCPU(StringRef CPU) const {
   const MCSchedModel &SchedModel = getSchedModelForCPU(CPU);
   return InstrItineraryData(SchedModel, Stages, OperandCycles, ForwardingPaths);
 }

 void MCSubtargetInfo::initInstrItins(InstrItineraryData &InstrItins) const {
   InstrItins = InstrItineraryData(getSchedModel(), Stages, OperandCycles,
                                   ForwardingPaths);
 }

 std::vector<SubtargetFeatureKV>
 MCSubtargetInfo::getEnabledProcessorFeatures() const {
   std::vector<SubtargetFeatureKV> EnabledFeatures;
   auto IsEnabled = [&](const SubtargetFeatureKV &FeatureKV) {
     return FeatureBits.test(FeatureKV.Value);
   };
   llvm::copy_if(ProcFeatures, std::back_inserter(EnabledFeatures), IsEnabled);
   return EnabledFeatures;
 }

 std::optional<unsigned> MCSubtargetInfo::getCacheSize(unsigned Level) const {
   return std::nullopt;
 }

 std::optional<unsigned>
 MCSubtargetInfo::getCacheAssociativity(unsigned Level) const {
   return std::nullopt;
 }

 std::optional<unsigned>
 MCSubtargetInfo::getCacheLineSize(unsigned Level) const {
   return std::nullopt;
 }

 unsigned MCSubtargetInfo::getPrefetchDistance() const {
   return 0;
 }

 unsigned MCSubtargetInfo::getMaxPrefetchIterationsAhead() const {
   return UINT_MAX;
 }

 bool MCSubtargetInfo::enableWritePrefetching() const {
   return false;
 }

 unsigned MCSubtargetInfo::getMinPrefetchStride(unsigned NumMemAccesses,
                                                unsigned NumStridedMemAccesses,
                                                unsigned NumPrefetches,
                                                bool HasCall) const {
   return 1;
 }

 bool MCSubtargetInfo::shouldPrefetchAddressSpace(unsigned AS) const {
   return !AS;
 }
	//===- MCSubtargetInfo.cpp - Subtarget Information ------------------------===//
	//
	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
	// See https://llvm.org/LICENSE.txt for license information.
	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
	//
	//===----------------------------------------------------------------------===//

	#include "llvm/MC/MCSubtargetInfo.h"
	#include "llvm/ADT/ArrayRef.h"
	#include "llvm/ADT/StringRef.h"
	#include "llvm/MC/MCInstrItineraries.h"
	#include "llvm/MC/MCSchedule.h"
	#include "llvm/Support/Format.h"
	#include "llvm/Support/raw_ostream.h"
	#include "llvm/TargetParser/SubtargetFeature.h"
	#include <algorithm>
	#include <cassert>
	#include <cstring>
	#include <optional>

	using namespace llvm;

	/// Find KV in array using binary search.
	template <typename T>
	static const T *Find(StringRef S, ArrayRef<T> A) {
	// Binary search the array
	auto F = llvm::lower_bound(A, S);
	// If not found then return NULL
	if (F == A.end() \|\| StringRef(F->Key) != S) return nullptr;
	// Return the found array item
	return F;
	}

	/// For each feature that is (transitively) implied by this feature, set it.
	static
	void SetImpliedBits(FeatureBitset &Bits, const FeatureBitset &Implies,
	ArrayRef<SubtargetFeatureKV> FeatureTable) {
	// OR the Implies bits in outside the loop. This allows the Implies for CPUs
	// which might imply features not in FeatureTable to use this.
	Bits \|= Implies;
	for (const SubtargetFeatureKV &FE : FeatureTable)
	if (Implies.test(FE.Value))
	SetImpliedBits(Bits, FE.Implies.getAsBitset(), FeatureTable);
	}

	/// For each feature that (transitively) implies this feature, clear it.
	static
	void ClearImpliedBits(FeatureBitset &Bits, unsigned Value,
	ArrayRef<SubtargetFeatureKV> FeatureTable) {
	for (const SubtargetFeatureKV &FE : FeatureTable) {
	if (FE.Implies.getAsBitset().test(Value)) {
	Bits.reset(FE.Value);
	ClearImpliedBits(Bits, FE.Value, FeatureTable);
	}
	}
	}

	static void ApplyFeatureFlag(FeatureBitset &Bits, StringRef Feature,
	ArrayRef<SubtargetFeatureKV> FeatureTable) {
	assert(SubtargetFeatures::hasFlag(Feature) &&
	"Feature flags should start with '+' or '-'");

	// Find feature in table.
	const SubtargetFeatureKV *FeatureEntry =
	Find(SubtargetFeatures::StripFlag(Feature), FeatureTable);
	// If there is a match
	if (FeatureEntry) {
	// Enable/disable feature in bits
	if (SubtargetFeatures::isEnabled(Feature)) {
	Bits.set(FeatureEntry->Value);

	// For each feature that this implies, set it.
	SetImpliedBits(Bits, FeatureEntry->Implies.getAsBitset(), FeatureTable);
	} else {
	Bits.reset(FeatureEntry->Value);

	// For each feature that implies this, clear it.
	ClearImpliedBits(Bits, FeatureEntry->Value, FeatureTable);
	}
	} else {
	errs() << "'" << Feature << "' is not a recognized feature for this target"
	<< " (ignoring feature)\n";
	}
	}

	/// Return the length of the longest entry in the table.
	template <typename T>
	static size_t getLongestEntryLength(ArrayRef<T> Table) {
	size_t MaxLen = 0;
	for (auto &I : Table)
	MaxLen = std::max(MaxLen, std::strlen(I.Key));
	return MaxLen;
	}

	/// Display help for feature and mcpu choices.
	static void Help(ArrayRef<SubtargetSubTypeKV> CPUTable,
	ArrayRef<SubtargetFeatureKV> FeatTable) {
	// the static variable ensures that the help information only gets
	// printed once even though a target machine creates multiple subtargets
	static bool PrintOnce = false;
	if (PrintOnce) {
	return;
	}

	// Determine the length of the longest CPU and Feature entries.
	unsigned MaxCPULen = getLongestEntryLength(CPUTable);
	unsigned MaxFeatLen = getLongestEntryLength(FeatTable);

	// Print the CPU table.
	errs() << "Available CPUs for this target:\n\n";
	for (auto &CPU : CPUTable)
	errs() << format(" %-*s - Select the %s processor.\n", MaxCPULen, CPU.Key,
	CPU.Key);
	errs() << '\n';

	// Print the Feature table.
	errs() << "Available features for this target:\n\n";
	for (auto &Feature : FeatTable)
	errs() << format(" %-*s - %s.\n", MaxFeatLen, Feature.Key, Feature.Desc);
	errs() << '\n';

	errs() << "Use +feature to enable a feature, or -feature to disable it.\n"
	"For example, llc -mcpu=mycpu -mattr=+feature1,-feature2\n";

	PrintOnce = true;
	}

	/// Display help for mcpu choices only
	static void cpuHelp(ArrayRef<SubtargetSubTypeKV> CPUTable) {
	// the static variable ensures that the help information only gets
	// printed once even though a target machine creates multiple subtargets
	static bool PrintOnce = false;
	if (PrintOnce) {
	return;
	}

	// Print the CPU table.
	errs() << "Available CPUs for this target:\n\n";
	for (auto &CPU : CPUTable)
	errs() << "\t" << CPU.Key << "\n";
	errs() << '\n';

	errs() << "Use -mcpu or -mtune to specify the target's processor.\n"
	"For example, clang --target=aarch64-unknown-linux-gnu "
	"-mcpu=cortex-a35\n";

	PrintOnce = true;
	}

	static FeatureBitset getFeatures(StringRef CPU, StringRef TuneCPU, StringRef FS,
	ArrayRef<SubtargetSubTypeKV> ProcDesc,
	ArrayRef<SubtargetFeatureKV> ProcFeatures) {
	SubtargetFeatures Features(FS);

	if (ProcDesc.empty() \|\| ProcFeatures.empty())
	return FeatureBitset();

	assert(llvm::is_sorted(ProcDesc) && "CPU table is not sorted");
	assert(llvm::is_sorted(ProcFeatures) && "CPU features table is not sorted");
	// Resulting bits
	FeatureBitset Bits;

	// Check if help is needed
	if (CPU == "help")
	Help(ProcDesc, ProcFeatures);

	// Find CPU entry if CPU name is specified.
	else if (!CPU.empty()) {
	const SubtargetSubTypeKV *CPUEntry = Find(CPU, ProcDesc);

	// If there is a match
	if (CPUEntry) {
	// Set the features implied by this CPU feature, if any.
	SetImpliedBits(Bits, CPUEntry->Implies.getAsBitset(), ProcFeatures);
	} else {
	errs() << "'" << CPU << "' is not a recognized processor for this target"
	<< " (ignoring processor)\n";
	}
	}

	if (!TuneCPU.empty()) {
	const SubtargetSubTypeKV *CPUEntry = Find(TuneCPU, ProcDesc);

	// If there is a match
	if (CPUEntry) {
	// Set the features implied by this CPU feature, if any.
	SetImpliedBits(Bits, CPUEntry->TuneImplies.getAsBitset(), ProcFeatures);
	} else if (TuneCPU != CPU) {
	errs() << "'" << TuneCPU << "' is not a recognized processor for this "
	<< "target (ignoring processor)\n";
	}
	}

	// Iterate through each feature
	for (const std::string &Feature : Features.getFeatures()) {
	// Check for help
	if (Feature == "+help")
	Help(ProcDesc, ProcFeatures);
	else if (Feature == "+cpuhelp")
	cpuHelp(ProcDesc);
	else
	ApplyFeatureFlag(Bits, Feature, ProcFeatures);
	}

	return Bits;
	}

	void MCSubtargetInfo::InitMCProcessorInfo(StringRef CPU, StringRef TuneCPU,
	StringRef FS) {
	FeatureBits = getFeatures(CPU, TuneCPU, FS, ProcDesc, ProcFeatures);
	FeatureString = std::string(FS);

	if (!TuneCPU.empty())
	CPUSchedModel = &getSchedModelForCPU(TuneCPU);
	else
	CPUSchedModel = &MCSchedModel::Default;
	}

	void MCSubtargetInfo::setDefaultFeatures(StringRef CPU, StringRef TuneCPU,
	StringRef FS) {
	FeatureBits = getFeatures(CPU, TuneCPU, FS, ProcDesc, ProcFeatures);
	FeatureString = std::string(FS);
	}

	MCSubtargetInfo::MCSubtargetInfo(const Triple &TT, StringRef C, StringRef TC,
	StringRef FS, ArrayRef<SubtargetFeatureKV> PF,
	ArrayRef<SubtargetSubTypeKV> PD,
	const MCWriteProcResEntry *WPR,
	const MCWriteLatencyEntry *WL,
	const MCReadAdvanceEntry *RA,
	const InstrStage IS, const unsigned OC,
	const unsigned *FP)
	: TargetTriple(TT), CPU(std::string(C)), TuneCPU(std::string(TC)),
	ProcFeatures(PF), ProcDesc(PD), WriteProcResTable(WPR),
	WriteLatencyTable(WL), ReadAdvanceTable(RA), Stages(IS),
	OperandCycles(OC), ForwardingPaths(FP) {
	InitMCProcessorInfo(CPU, TuneCPU, FS);
	}

	FeatureBitset MCSubtargetInfo::ToggleFeature(uint64_t FB) {
	FeatureBits.flip(FB);
	return FeatureBits;
	}

	FeatureBitset MCSubtargetInfo::ToggleFeature(const FeatureBitset &FB) {
	FeatureBits ^= FB;
	return FeatureBits;
	}

	FeatureBitset MCSubtargetInfo::SetFeatureBitsTransitively(
	const FeatureBitset &FB) {
	SetImpliedBits(FeatureBits, FB, ProcFeatures);
	return FeatureBits;
	}

	FeatureBitset MCSubtargetInfo::ClearFeatureBitsTransitively(
	const FeatureBitset &FB) {
	for (unsigned I = 0, E = FB.size(); I < E; I++) {
	if (FB[I]) {
	FeatureBits.reset(I);
	ClearImpliedBits(FeatureBits, I, ProcFeatures);
	}
	}
	return FeatureBits;
	}

	FeatureBitset MCSubtargetInfo::ToggleFeature(StringRef Feature) {
	// Find feature in table.
	const SubtargetFeatureKV *FeatureEntry =
	Find(SubtargetFeatures::StripFlag(Feature), ProcFeatures);
	// If there is a match
	if (FeatureEntry) {
	if (FeatureBits.test(FeatureEntry->Value)) {
	FeatureBits.reset(FeatureEntry->Value);
	// For each feature that implies this, clear it.
	ClearImpliedBits(FeatureBits, FeatureEntry->Value, ProcFeatures);
	} else {
	FeatureBits.set(FeatureEntry->Value);

	// For each feature that this implies, set it.
	SetImpliedBits(FeatureBits, FeatureEntry->Implies.getAsBitset(),
	ProcFeatures);
	}
	} else {
	errs() << "'" << Feature << "' is not a recognized feature for this target"
	<< " (ignoring feature)\n";
	}

	return FeatureBits;
	}

	FeatureBitset MCSubtargetInfo::ApplyFeatureFlag(StringRef FS) {
	::ApplyFeatureFlag(FeatureBits, FS, ProcFeatures);
	return FeatureBits;
	}

	bool MCSubtargetInfo::checkFeatures(StringRef FS) const {
	SubtargetFeatures T(FS);
	FeatureBitset Set, All;
	for (std::string F : T.getFeatures()) {
	::ApplyFeatureFlag(Set, F, ProcFeatures);
	if (F[0] == '-')
	F[0] = '+';
	::ApplyFeatureFlag(All, F, ProcFeatures);
	}
	return (FeatureBits & All) == Set;
	}

	const MCSchedModel &MCSubtargetInfo::getSchedModelForCPU(StringRef CPU) const {
	assert(llvm::is_sorted(ProcDesc) &&
	"Processor machine model table is not sorted");

	// Find entry
	const SubtargetSubTypeKV *CPUEntry = Find(CPU, ProcDesc);

	if (!CPUEntry) {
	if (CPU != "help") // Don't error if the user asked for help.
	errs() << "'" << CPU
	<< "' is not a recognized processor for this target"
	<< " (ignoring processor)\n";
	return MCSchedModel::Default;
	}
	assert(CPUEntry->SchedModel && "Missing processor SchedModel value");
	return *CPUEntry->SchedModel;
	}

	InstrItineraryData
	MCSubtargetInfo::getInstrItineraryForCPU(StringRef CPU) const {
	const MCSchedModel &SchedModel = getSchedModelForCPU(CPU);
	return InstrItineraryData(SchedModel, Stages, OperandCycles, ForwardingPaths);
	}

	void MCSubtargetInfo::initInstrItins(InstrItineraryData &InstrItins) const {
	InstrItins = InstrItineraryData(getSchedModel(), Stages, OperandCycles,
	ForwardingPaths);
	}

	std::vector<SubtargetFeatureKV>
	MCSubtargetInfo::getEnabledProcessorFeatures() const {
	std::vector<SubtargetFeatureKV> EnabledFeatures;
	auto IsEnabled = [&](const SubtargetFeatureKV &FeatureKV) {
	return FeatureBits.test(FeatureKV.Value);
	};
	llvm::copy_if(ProcFeatures, std::back_inserter(EnabledFeatures), IsEnabled);
	return EnabledFeatures;
	}

	std::optional<unsigned> MCSubtargetInfo::getCacheSize(unsigned Level) const {
	return std::nullopt;
	}

	std::optional<unsigned>
	MCSubtargetInfo::getCacheAssociativity(unsigned Level) const {
	return std::nullopt;
	}

	std::optional<unsigned>
	MCSubtargetInfo::getCacheLineSize(unsigned Level) const {
	return std::nullopt;
	}

	unsigned MCSubtargetInfo::getPrefetchDistance() const {
	return 0;
	}

	unsigned MCSubtargetInfo::getMaxPrefetchIterationsAhead() const {
	return UINT_MAX;
	}

	bool MCSubtargetInfo::enableWritePrefetching() const {
	return false;
	}

	unsigned MCSubtargetInfo::getMinPrefetchStride(unsigned NumMemAccesses,
	unsigned NumStridedMemAccesses,
	unsigned NumPrefetches,
	bool HasCall) const {
	return 1;
	}

	bool MCSubtargetInfo::shouldPrefetchAddressSpace(unsigned AS) const {
	return !AS;
	}