diff --git a/content/base/public/nsIDocument.h b/content/base/public/nsIDocument.h
index 89ac00bbff5..e2e39a262ca 100644
--- a/content/base/public/nsIDocument.h
+++ b/content/base/public/nsIDocument.h
@@ -166,7 +166,7 @@ public:
       mIsBeingUsedAsImage(PR_FALSE),
       mPartID(0)
   {
-    mParentPtrBits |= PARENT_BIT_INDOCUMENT;
+    SetInDocument();
   }
 #endif
   
diff --git a/content/base/public/nsINode.h b/content/base/public/nsINode.h
index 5b01b4791e9..60c673321cd 100644
--- a/content/base/public/nsINode.h
+++ b/content/base/public/nsINode.h
@@ -315,12 +315,12 @@ public:
 #ifdef MOZILLA_INTERNAL_API
   nsINode(already_AddRefed<nsINodeInfo> aNodeInfo)
   : mNodeInfo(aNodeInfo),
-    mParentPtrBits(0),
+    mParent(nsnull),
     mFlags(0),
+    mBoolFlags(0),
     mNextSibling(nsnull),
     mPreviousSibling(nsnull),
     mFirstChild(nsnull),
-    mNodeHasRenderingObservers(false),
     mSlots(nsnull)
   {
   }
@@ -433,9 +433,9 @@ public:
    *
    * @return whether this content is in a document tree
    */
-  PRBool IsInDoc() const
+  bool IsInDoc() const
   {
-    return mParentPtrBits & PARENT_BIT_INDOCUMENT;
+    return GetBoolFlag(IsInDocument);
   }
 
   /**
@@ -704,13 +704,11 @@ public:
   /**
    * Get the parent nsIContent for this node.
    * @return the parent, or null if no parent or the parent is not an nsIContent
+   * Implemented in nsIContent.h
    */
-  nsIContent* GetParent() const
-  {
-    return NS_LIKELY(mParentPtrBits & PARENT_BIT_PARENT_IS_CONTENT) ?
-           reinterpret_cast<nsIContent*>
-                           (mParentPtrBits & ~kParentBitMask) :
-           nsnull;
+  nsIContent* GetParent() const {
+    return NS_LIKELY(GetBoolFlag(ParentIsContent)) ?
+      reinterpret_cast<nsIContent*>(mParent) : nsnull;
   }
 
   /**
@@ -720,7 +718,7 @@ public:
    */
   nsINode* GetNodeParent() const
   {
-    return reinterpret_cast<nsINode*>(mParentPtrBits & ~kParentBitMask);
+    return mParent;
   }
 
   /**
@@ -1136,9 +1134,53 @@ public:
     NS_NOTREACHED("How did we get here?");
   }
 
-  bool HasRenderingObservers() { return mNodeHasRenderingObservers; }
+  /**
+   * Boolean flags
+   */
+private:
+  enum BooleanFlag {
+    // Set if we're being used from -moz-element
+    NodeHasRenderingObservers,
+    // Set if our parent chain (including this node itself) terminates
+    // in a document
+    IsInDocument,
+    // Set if mParent is an nsIContent
+    ParentIsContent,
+    BooleanFlagCount
+  };
+
+  void SetBoolFlag(BooleanFlag name, bool value) {
+    PR_STATIC_ASSERT(BooleanFlagCount <= 8*sizeof(mBoolFlags));
+    mBoolFlags = (mBoolFlags & ~(1 << name)) | (value << name);
+  }
+
+  void SetBoolFlag(BooleanFlag name) {
+    PR_STATIC_ASSERT(BooleanFlagCount <= 8*sizeof(mBoolFlags));
+    mBoolFlags |= (1 << name);
+  }
+
+  void ClearBoolFlag(BooleanFlag name) {
+    PR_STATIC_ASSERT(BooleanFlagCount <= 8*sizeof(mBoolFlags));
+    mBoolFlags &= ~(1 << name);
+  }
+
+  bool GetBoolFlag(BooleanFlag name) const {
+    PR_STATIC_ASSERT(BooleanFlagCount <= 8*sizeof(mBoolFlags));
+    return mBoolFlags & (1 << name);
+  }
+
+public:
+  bool HasRenderingObservers() const
+    { return GetBoolFlag(NodeHasRenderingObservers); }
   void SetHasRenderingObservers(bool aValue)
-    { mNodeHasRenderingObservers = aValue; }
+    { SetBoolFlag(NodeHasRenderingObservers, aValue); }
+
+protected:
+  void SetParentIsContent(bool aValue) { SetBoolFlag(ParentIsContent, aValue); }
+  void SetInDocument() { SetBoolFlag(IsInDocument); }
+  void ClearInDocument() { ClearBoolFlag(IsInDocument); }
+
+public:
 
   // Optimized way to get classinfo.
   virtual nsXPCClassInfo* GetClassInfo() = 0;
@@ -1244,20 +1286,19 @@ protected:
 
   nsCOMPtr<nsINodeInfo> mNodeInfo;
 
-  enum { PARENT_BIT_INDOCUMENT = 1 << 0, PARENT_BIT_PARENT_IS_CONTENT = 1 << 1 };
-  enum { kParentBitMask = 0x3 };
-
-  PtrBits mParentPtrBits;
+  nsINode* mParent;
 
   PRUint32 mFlags;
 
+private:
+  // Boolean flags.
+  PRUint32 mBoolFlags;
+
+protected:
   nsIContent* mNextSibling;
   nsIContent* mPreviousSibling;
   nsIContent* mFirstChild;
 
-  // More flags
-  bool mNodeHasRenderingObservers : 1;
-
   // Storage for more members that are usually not needed; allocated lazily.
   nsSlots* mSlots;
 };
diff --git a/content/base/src/nsGenericDOMDataNode.cpp b/content/base/src/nsGenericDOMDataNode.cpp
index 98452cc4d11..7fdcf6b5c58 100644
--- a/content/base/src/nsGenericDOMDataNode.cpp
+++ b/content/base/src/nsGenericDOMDataNode.cpp
@@ -523,19 +523,19 @@ nsGenericDOMDataNode::BindToTree(nsIDocument* aDocument, nsIContent* aParent,
 
   // Set parent
   if (aParent) {
-    mParentPtrBits =
-      reinterpret_cast<PtrBits>(aParent) | PARENT_BIT_PARENT_IS_CONTENT;
+    mParent = aParent;
   }
   else {
-    mParentPtrBits = reinterpret_cast<PtrBits>(aDocument);
+    mParent = aDocument;
   }
+  SetParentIsContent(aParent);
 
   // XXXbz sXBL/XBL2 issue!
 
   // Set document
   if (aDocument) {
     // XXX See the comment in nsGenericElement::BindToTree
-    mParentPtrBits |= PARENT_BIT_INDOCUMENT;
+    SetInDocument();
     if (mText.IsBidi()) {
       aDocument->SetBidiEnabled();
     }
@@ -570,7 +570,11 @@ nsGenericDOMDataNode::UnbindFromTree(PRBool aDeep, PRBool aNullParent)
     document->BindingManager()->RemovedFromDocument(this, document);
   }
 
-  mParentPtrBits = aNullParent ? 0 : mParentPtrBits & ~PARENT_BIT_INDOCUMENT;
+  if (aNullParent) {
+    mParent = nsnull;
+    SetParentIsContent(false);
+  }
+  ClearInDocument();
 
   nsDataSlots *slots = GetExistingDataSlots();
   if (slots) {
diff --git a/content/base/src/nsGenericElement.cpp b/content/base/src/nsGenericElement.cpp
index 3d910679101..c6e0ea8e8f7 100644
--- a/content/base/src/nsGenericElement.cpp
+++ b/content/base/src/nsGenericElement.cpp
@@ -2943,15 +2943,16 @@ nsGenericElement::BindToTree(nsIDocument* aDocument, nsIContent* aParent,
 
   // Now set the parent and set the "Force attach xbl" flag if needed.
   if (aParent) {
-    mParentPtrBits = reinterpret_cast<PtrBits>(aParent) | PARENT_BIT_PARENT_IS_CONTENT;
+    mParent = aParent;
 
     if (aParent->HasFlag(NODE_FORCE_XBL_BINDINGS)) {
       SetFlags(NODE_FORCE_XBL_BINDINGS);
     }
   }
   else {
-    mParentPtrBits = reinterpret_cast<PtrBits>(aDocument);
+    mParent = aDocument;
   }
+  SetParentIsContent(aParent);
 
   // XXXbz sXBL/XBL2 issue!
 
@@ -2967,7 +2968,7 @@ nsGenericElement::BindToTree(nsIDocument* aDocument, nsIContent* aParent,
     //                                                   aDocument);
 
     // Being added to a document.
-    mParentPtrBits |= PARENT_BIT_INDOCUMENT;
+    SetInDocument();
 
     // Unset this flag since we now really are in a document.
     UnsetFlags(NODE_FORCE_XBL_BINDINGS |
@@ -3049,7 +3050,11 @@ nsGenericElement::UnbindFromTree(PRBool aDeep, PRBool aNullParent)
   nsIDocument *document =
     HasFlag(NODE_FORCE_XBL_BINDINGS) ? GetOwnerDoc() : GetCurrentDoc();
 
-  mParentPtrBits = aNullParent ? 0 : mParentPtrBits & ~PARENT_BIT_INDOCUMENT;
+  if (aNullParent) {
+    mParent = nsnull;
+    SetParentIsContent(false);
+  }
+  ClearInDocument();
 
   if (document) {
     // Notify XBL- & nsIAnonymousContentCreator-generated
diff --git a/content/base/src/nsTextNode.cpp b/content/base/src/nsTextNode.cpp
index d915743cf10..c3dc9be6da1 100644
--- a/content/base/src/nsTextNode.cpp
+++ b/content/base/src/nsTextNode.cpp
@@ -215,7 +215,9 @@ nsTextNode::BindToAttribute(nsIAttribute* aAttr)
   NS_ASSERTION(!GetNodeParent(), "Unbind before binding!");
   NS_ASSERTION(HasSameOwnerDoc(aAttr), "Wrong owner document!");
 
-  mParentPtrBits = reinterpret_cast<PtrBits>(aAttr);
+  mParent = aAttr;
+  SetParentIsContent(false);
+  ClearInDocument();
   return NS_OK;
 }
 
@@ -226,7 +228,7 @@ nsTextNode::UnbindFromAttribute()
   NS_ASSERTION(GetNodeParent() &&
                GetNodeParent()->IsNodeOfType(nsINode::eATTRIBUTE),
                "Use this method only to unbind from an attribute!");
-  mParentPtrBits = 0;
+  mParent = nsnull;
   return NS_OK;
 }