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diff --git a/clang-r353983/include/llvm/Analysis/DemandedBits.h b/clang-r353983/include/llvm/Analysis/DemandedBits.h
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+//===- llvm/Analysis/DemandedBits.h - Determine demanded bits ---*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This pass implements a demanded bits analysis. A demanded bit is one that
+// contributes to a result; bits that are not demanded can be either zero or
+// one without affecting control or data flow. For example in this sequence:
+//
+//   %1 = add i32 %x, %y
+//   %2 = trunc i32 %1 to i16
+//
+// Only the lowest 16 bits of %1 are demanded; the rest are removed by the
+// trunc.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_DEMANDED_BITS_H
+#define LLVM_ANALYSIS_DEMANDED_BITS_H
+
+#include "llvm/ADT/APInt.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/Optional.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/IR/PassManager.h"
+#include "llvm/Pass.h"
+
+namespace llvm {
+
+class AssumptionCache;
+class DominatorTree;
+class Function;
+class Instruction;
+struct KnownBits;
+class raw_ostream;
+
+class DemandedBits {
+public:
+  DemandedBits(Function &F, AssumptionCache &AC, DominatorTree &DT) :
+    F(F), AC(AC), DT(DT) {}
+
+  /// Return the bits demanded from instruction I.
+  ///
+  /// For vector instructions individual vector elements are not distinguished:
+  /// A bit is demanded if it is demanded for any of the vector elements. The
+  /// size of the return value corresponds to the type size in bits of the
+  /// scalar type.
+  ///
+  /// Instructions that do not have integer or vector of integer type are
+  /// accepted, but will always produce a mask with all bits set.
+  APInt getDemandedBits(Instruction *I);
+
+  /// Return true if, during analysis, I could not be reached.
+  bool isInstructionDead(Instruction *I);
+
+  /// Return whether this use is dead by means of not having any demanded bits.
+  bool isUseDead(Use *U);
+
+  void print(raw_ostream &OS);
+
+private:
+  void performAnalysis();
+  void determineLiveOperandBits(const Instruction *UserI,
+    const Value *Val, unsigned OperandNo,
+    const APInt &AOut, APInt &AB,
+    KnownBits &Known, KnownBits &Known2, bool &KnownBitsComputed);
+
+  Function &F;
+  AssumptionCache &AC;
+  DominatorTree &DT;
+
+  bool Analyzed = false;
+
+  // The set of visited instructions (non-integer-typed only).
+  SmallPtrSet<Instruction*, 32> Visited;
+  DenseMap<Instruction *, APInt> AliveBits;
+  // Uses with no demanded bits. If the user also has no demanded bits, the use
+  // might not be stored explicitly in this map, to save memory during analysis.
+  SmallPtrSet<Use *, 16> DeadUses;
+};
+
+class DemandedBitsWrapperPass : public FunctionPass {
+private:
+  mutable Optional<DemandedBits> DB;
+
+public:
+  static char ID; // Pass identification, replacement for typeid
+
+  DemandedBitsWrapperPass();
+
+  bool runOnFunction(Function &F) override;
+  void getAnalysisUsage(AnalysisUsage &AU) const override;
+
+  /// Clean up memory in between runs
+  void releaseMemory() override;
+
+  DemandedBits &getDemandedBits() { return *DB; }
+
+  void print(raw_ostream &OS, const Module *M) const override;
+};
+
+/// An analysis that produces \c DemandedBits for a function.
+class DemandedBitsAnalysis : public AnalysisInfoMixin<DemandedBitsAnalysis> {
+  friend AnalysisInfoMixin<DemandedBitsAnalysis>;
+
+  static AnalysisKey Key;
+
+public:
+  /// Provide the result type for this analysis pass.
+  using Result = DemandedBits;
+
+  /// Run the analysis pass over a function and produce demanded bits
+  /// information.
+  DemandedBits run(Function &F, FunctionAnalysisManager &AM);
+};
+
+/// Printer pass for DemandedBits
+class DemandedBitsPrinterPass : public PassInfoMixin<DemandedBitsPrinterPass> {
+  raw_ostream &OS;
+
+public:
+  explicit DemandedBitsPrinterPass(raw_ostream &OS) : OS(OS) {}
+
+  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
+};
+
+/// Create a demanded bits analysis pass.
+FunctionPass *createDemandedBitsWrapperPass();
+
+} // end namespace llvm
+
+#endif // LLVM_ANALYSIS_DEMANDED_BITS_H