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diff --git a/clang-r353983/include/llvm/IR/Use.h b/clang-r353983/include/llvm/IR/Use.h
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+//===- llvm/Use.h - Definition of the Use class -----------------*- 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
+//
+//===----------------------------------------------------------------------===//
+/// \file
+///
+/// This defines the Use class.  The Use class represents the operand of an
+/// instruction or some other User instance which refers to a Value.  The Use
+/// class keeps the "use list" of the referenced value up to date.
+///
+/// Pointer tagging is used to efficiently find the User corresponding to a Use
+/// without having to store a User pointer in every Use. A User is preceded in
+/// memory by all the Uses corresponding to its operands, and the low bits of
+/// one of the fields (Prev) of the Use class are used to encode offsets to be
+/// able to find that User given a pointer to any Use. For details, see:
+///
+///   http://www.llvm.org/docs/ProgrammersManual.html#UserLayout
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_IR_USE_H
+#define LLVM_IR_USE_H
+
+#include "llvm-c/Types.h"
+#include "llvm/ADT/PointerIntPair.h"
+#include "llvm/Support/CBindingWrapping.h"
+#include "llvm/Support/Compiler.h"
+
+namespace llvm {
+
+template <typename> struct simplify_type;
+class User;
+class Value;
+
+/// A Use represents the edge between a Value definition and its users.
+///
+/// This is notionally a two-dimensional linked list. It supports traversing
+/// all of the uses for a particular value definition. It also supports jumping
+/// directly to the used value when we arrive from the User's operands, and
+/// jumping directly to the User when we arrive from the Value's uses.
+///
+/// The pointer to the used Value is explicit, and the pointer to the User is
+/// implicit. The implicit pointer is found via a waymarking algorithm
+/// described in the programmer's manual:
+///
+///   http://www.llvm.org/docs/ProgrammersManual.html#the-waymarking-algorithm
+///
+/// This is essentially the single most memory intensive object in LLVM because
+/// of the number of uses in the system. At the same time, the constant time
+/// operations it allows are essential to many optimizations having reasonable
+/// time complexity.
+class Use {
+public:
+  Use(const Use &U) = delete;
+
+  /// Provide a fast substitute to std::swap<Use>
+  /// that also works with less standard-compliant compilers
+  void swap(Use &RHS);
+
+  /// Pointer traits for the UserRef PointerIntPair. This ensures we always
+  /// use the LSB regardless of pointer alignment on different targets.
+  struct UserRefPointerTraits {
+    static inline void *getAsVoidPointer(User *P) { return P; }
+
+    static inline User *getFromVoidPointer(void *P) {
+      return (User *)P;
+    }
+
+    enum { NumLowBitsAvailable = 1 };
+  };
+
+  // A type for the word following an array of hung-off Uses in memory, which is
+  // a pointer back to their User with the bottom bit set.
+  using UserRef = PointerIntPair<User *, 1, unsigned, UserRefPointerTraits>;
+
+  /// Pointer traits for the Prev PointerIntPair. This ensures we always use
+  /// the two LSBs regardless of pointer alignment on different targets.
+  struct PrevPointerTraits {
+    static inline void *getAsVoidPointer(Use **P) { return P; }
+
+    static inline Use **getFromVoidPointer(void *P) {
+      return (Use **)P;
+    }
+
+    enum { NumLowBitsAvailable = 2 };
+  };
+
+private:
+  /// Destructor - Only for zap()
+  ~Use() {
+    if (Val)
+      removeFromList();
+  }
+
+  enum PrevPtrTag { zeroDigitTag, oneDigitTag, stopTag, fullStopTag };
+
+  /// Constructor
+  Use(PrevPtrTag tag) { Prev.setInt(tag); }
+
+public:
+  friend class Value;
+
+  operator Value *() const { return Val; }
+  Value *get() const { return Val; }
+
+  /// Returns the User that contains this Use.
+  ///
+  /// For an instruction operand, for example, this will return the
+  /// instruction.
+  User *getUser() const LLVM_READONLY;
+
+  inline void set(Value *Val);
+
+  inline Value *operator=(Value *RHS);
+  inline const Use &operator=(const Use &RHS);
+
+  Value *operator->() { return Val; }
+  const Value *operator->() const { return Val; }
+
+  Use *getNext() const { return Next; }
+
+  /// Return the operand # of this use in its User.
+  unsigned getOperandNo() const;
+
+  /// Initializes the waymarking tags on an array of Uses.
+  ///
+  /// This sets up the array of Uses such that getUser() can find the User from
+  /// any of those Uses.
+  static Use *initTags(Use *Start, Use *Stop);
+
+  /// Destroys Use operands when the number of operands of
+  /// a User changes.
+  static void zap(Use *Start, const Use *Stop, bool del = false);
+
+private:
+  const Use *getImpliedUser() const LLVM_READONLY;
+
+  Value *Val = nullptr;
+  Use *Next;
+  PointerIntPair<Use **, 2, PrevPtrTag, PrevPointerTraits> Prev;
+
+  void setPrev(Use **NewPrev) { Prev.setPointer(NewPrev); }
+
+  void addToList(Use **List) {
+    Next = *List;
+    if (Next)
+      Next->setPrev(&Next);
+    setPrev(List);
+    *List = this;
+  }
+
+  void removeFromList() {
+    Use **StrippedPrev = Prev.getPointer();
+    *StrippedPrev = Next;
+    if (Next)
+      Next->setPrev(StrippedPrev);
+  }
+};
+
+/// Allow clients to treat uses just like values when using
+/// casting operators.
+template <> struct simplify_type<Use> {
+  using SimpleType = Value *;
+
+  static SimpleType getSimplifiedValue(Use &Val) { return Val.get(); }
+};
+template <> struct simplify_type<const Use> {
+  using SimpleType = /*const*/ Value *;
+
+  static SimpleType getSimplifiedValue(const Use &Val) { return Val.get(); }
+};
+
+// Create wrappers for C Binding types (see CBindingWrapping.h).
+DEFINE_SIMPLE_CONVERSION_FUNCTIONS(Use, LLVMUseRef)
+
+} // end namespace llvm
+
+#endif // LLVM_IR_USE_H