diff --git a/lib/Bytecode/Reader/Reader.cpp b/lib/Bytecode/Reader/Reader.cpp
index 3cc3b1d..2ac92bc 100644
--- a/lib/Bytecode/Reader/Reader.cpp
+++ b/lib/Bytecode/Reader/Reader.cpp
@@ -1192,7 +1192,18 @@
       Typ = read_vbr_uint();
     }
 
-    Result = StructType::get(Elements);
+    Result = StructType::get(Elements, false);
+    break;
+  }
+  case Type::BC_ONLY_PackedStructTyID: {
+    std::vector<const Type*> Elements;
+    unsigned Typ = read_vbr_uint();
+    while (Typ) {         // List is terminated by void/0 typeid
+      Elements.push_back(getType(Typ));
+      Typ = read_vbr_uint();
+    }
+
+    Result = StructType::get(Elements, true);
     break;
   }
   case Type::PointerTyID: {
diff --git a/lib/Bytecode/Writer/Writer.cpp b/lib/Bytecode/Writer/Writer.cpp
index b69c1ad..c6bc22e 100644
--- a/lib/Bytecode/Writer/Writer.cpp
+++ b/lib/Bytecode/Writer/Writer.cpp
@@ -197,7 +197,11 @@
 //===----------------------------------------------------------------------===//
 
 void BytecodeWriter::outputType(const Type *T) {
-  output_vbr((unsigned)T->getTypeID());
+  const StructType* STy = dyn_cast<StructType>(T);
+  if(STy && STy->isPacked())
+    output_vbr((unsigned)Type::BC_ONLY_PackedStructTyID);
+  else
+    output_vbr((unsigned)T->getTypeID());
 
   // That's all there is to handling primitive types...
   if (T->isPrimitiveType()) {
@@ -246,10 +250,8 @@
     break;
   }
 
-
   case Type::StructTyID: {
     const StructType *ST = cast<StructType>(T);
-
     // Output all of the element types...
     for (StructType::element_iterator I = ST->element_begin(),
            E = ST->element_end(); I != E; ++I) {