[IR] Fix some Clang-tidy modernize-use-equals-delete and Include What…

… You Use warnings; other minor fixes (NFC).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@288540 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/IR/Constant.h

@@ -15,11 +15,12 @@
 #define LLVM_IR_CONSTANT_H
 
 #include "llvm/IR/User.h"
+#include "llvm/IR/Value.h"
+#include "llvm/Support/Casting.h"
 
 namespace llvm {
-  class APInt;
 
-  template<typename T> class SmallVectorImpl;
+class APInt;
 
 /// This is an important base class in LLVM. It provides the common facilities
 /// of all constant values in an LLVM program. A constant is a value that is
@@ -39,15 +40,16 @@ namespace llvm {
 /// don't have to worry about the lifetime of the objects.
 /// @brief LLVM Constant Representation
 class Constant : public User {
-  void operator=(const Constant &) = delete;
-  Constant(const Constant &) = delete;
   void anchor() override;
 
 protected:
   Constant(Type *ty, ValueTy vty, Use *Ops, unsigned NumOps)
     : User(ty, vty, Ops, NumOps) {}
 
 public:
+  void operator=(const Constant &) = delete;
+  Constant(const Constant &) = delete;
+
   /// Return true if this is the value that would be returned by getNullValue.
   bool isNullValue() const;
 
@@ -159,6 +161,6 @@ class Constant : public User {
   }
 };
 
-} // End llvm namespace
+} // end namespace llvm
 
-#endif
+#endif // LLVM_IR_CONSTANT_H