diff --git a/llvm/include/llvm/Linker/IRMover.h b/llvm/include/llvm/Linker/IRMover.h
--- a/llvm/include/llvm/Linker/IRMover.h
+++ b/llvm/include/llvm/Linker/IRMover.h
@@ -12,6 +12,7 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/FunctionExtras.h"
+#include "llvm/ADT/iterator_range.h"
 #include <functional>
 
 namespace llvm {
@@ -58,6 +59,27 @@
     void addOpaque(StructType *Ty);
     StructType *findNonOpaque(ArrayRef<Type *> ETypes, bool IsPacked);
     bool hasType(StructType *Ty);
+
+    using const_non_opaque_iterator =
+        decltype(NonOpaqueStructTypes)::const_iterator;
+    const_non_opaque_iterator begin_non_opaque() const {
+      return NonOpaqueStructTypes.begin();
+    }
+    const_non_opaque_iterator end_non_opaque() const {
+      return NonOpaqueStructTypes.end();
+    }
+    llvm::iterator_range<const_non_opaque_iterator> range_non_opaque() {
+      return llvm::make_range(begin_non_opaque(), end_non_opaque());
+    }
+
+    using const_opaque_iterator = decltype(OpaqueStructTypes)::const_iterator;
+    const_opaque_iterator begin_opaque() const {
+      return OpaqueStructTypes.begin();
+    }
+    const_opaque_iterator end_opaque() const { return OpaqueStructTypes.end(); }
+    llvm::iterator_range<const_opaque_iterator> range_opaque() {
+      return llvm::make_range(begin_opaque(), end_opaque());
+    }
   };
 
   IRMover(Module &M);
diff --git a/llvm/lib/Linker/IRMover.cpp b/llvm/lib/Linker/IRMover.cpp
--- a/llvm/lib/Linker/IRMover.cpp
+++ b/llvm/lib/Linker/IRMover.cpp
@@ -14,6 +14,7 @@
 #include "llvm/ADT/Triple.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DebugInfoMetadata.h"
+#include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/DiagnosticPrinter.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/GVMaterializer.h"
@@ -55,7 +56,14 @@
 
 public:
   TypeMapTy(IRMover::IdentifiedStructTypeSet &DstStructTypesSet)
-      : DstStructTypesSet(DstStructTypesSet) {}
+      : DstStructTypesSet(DstStructTypesSet) {
+    // Existing destination types are mapped to themselves as they are already
+    // available.
+    for (StructType *OpaqueSTy : DstStructTypesSet.range_opaque())
+      MappedTypes[OpaqueSTy] = OpaqueSTy;
+    for (StructType *NonOpaqueSTy : DstStructTypesSet.range_non_opaque())
+      MappedTypes[NonOpaqueSTy] = NonOpaqueSTy;
+  }
 
   IRMover::IdentifiedStructTypeSet &DstStructTypesSet;
   /// Indicate that the specified type in the destination module is conceptually