[GlobalValue] Move HasLLVMReservedName into existing bitfield. NFC

[jlebar]

Summary

Follow-up to r290691, where I introduced HasLLVMReservedName. rnk
pointed out that that patch added an extra word to GlobalValue on MSVC,
because it doesn't pack bitfields with different types.

This patch moves HasLLVMReservedName into the existing bitfield, where
we appear to have plenty of bits to spare.

[rnk]

lgtm, thanks!

llvm/include/llvm/IR/GlobalValue.h

 
 protected:
   GlobalValue(Type *Ty, ValueTy VTy, Use *Ops, unsigned NumOps,
               LinkageTypes Linkage, const Twine &Name, unsigned AddressSpace)
       : Constant(PointerType::get(Ty, AddressSpace), VTy, Ops, NumOps),
         ValueType(Ty), Linkage(Linkage), Visibility(DefaultVisibility),
         UnnamedAddrVal(unsigned(UnnamedAddr::None)),
         DllStorageClass(DefaultStorageClass), ThreadLocal(NotThreadLocal),
-        IntID((Intrinsic::ID)0U), HasLLVMReservedName(false), Parent(nullptr) {
+        HasLLVMReservedName(false), IntID((Intrinsic::ID)0U), Parent(nullptr) {
     setName(Name);
   }
 
   Type *ValueType;
   // All bitfields use unsigned as the underlying type so that MSVC will pack
   // them.
   unsigned Linkage : 4;       // The linkage of this global
   unsigned Visibility : 2;    // The visibility style of this global
   unsigned UnnamedAddrVal : 2; // This value's address is not significant
   unsigned DllStorageClass : 2; // DLL storage class
 
   unsigned ThreadLocal : 3; // Is this symbol "Thread Local", if so, what is
                             // the desired model?
-  static const unsigned GlobalValueSubClassDataBits = 19;
+
+  /// True if the function's name starts with "llvm.".  This corresponds to the
+  /// value of Function::isIntrinsic(), which may be true even if
+  /// Function::intrinsicID() returns Intrinsic::not_intrinsic.
+  unsigned HasLLVMReservedName : 1;
+
+  static const unsigned GlobalValueSubClassDataBits = 18;
 
 private:
   friend class Constant;
 
   // Give subclasses access to what otherwise would be wasted padding.
-  // (19 + 4 + 2 + 2 + 2 + 3) == 32.
+  // (18 + 4 + 2 + 2 + 2 + 3 + 1) == 32.
   unsigned SubClassData : GlobalValueSubClassDataBits;
 
   void destroyConstantImpl();
   Value *handleOperandChangeImpl(Value *From, Value *To);
 
   /// Returns true if the definition of this global may be replaced by a
   /// differently optimized variant of the same source level function at link
   /// time.

 
 protected:
   /// \brief The intrinsic ID for this subclass (which must be a Function).
   ///
   /// This member is defined by this class, but not used for anything.
   /// Subclasses can use it to store their intrinsic ID, if they have one.
   ///
   /// This is stored here to save space in Function on 64-bit hosts.
-  Intrinsic::ID IntID : 31;
-
-  /// True if the function's name starts with "llvm.".  This corresponds to the
-  /// value of Function::isIntrinsic(), which may be true even if
-  /// Function::intrinsicID() returns Intrinsic::not_intrinsic.
-  bool HasLLVMReservedName : 1;
+  Intrinsic::ID IntID;
 
   unsigned getGlobalValueSubClassData() const {
     return SubClassData;
   }
   void setGlobalValueSubClassData(unsigned V) {
     assert(V < (1 << GlobalValueSubClassDataBits) && "It will not fit");
     SubClassData = V;
   }