Index: lib/Linker/LinkModules.cpp
===================================================================
--- lib/Linker/LinkModules.cpp
+++ lib/Linker/LinkModules.cpp
@@ -98,6 +98,8 @@
   Type *remapType(Type *SrcTy) override { return get(SrcTy); }
 
   bool areTypesIsomorphic(Type *DstTy, Type *SrcTy);
+
+  void addTrivialMapRecursively(Type *Ty);
 };
 }
 
@@ -142,7 +144,7 @@
   // Two identical types are clearly isomorphic.  Remember this
   // non-speculatively.
   if (DstTy == SrcTy) {
-    Entry = DstTy;
+    addTrivialMapRecursively(DstTy);
     return true;
   }
 
@@ -214,6 +216,22 @@
   return true;
 }
 
+/// For types which turn out to be the same Type instance in both modules,
+/// remembers this fact for it and all the contained types.
+///
+/// We need to be aware of this when performing the instruction rewrites
+/// laster on.
+void TypeMapTy::addTrivialMapRecursively(Type *Ty) {
+  Type *&Entry = MappedTypes[Ty];
+  if (Entry)
+    return;
+
+  Entry = Ty;
+  for (unsigned I = 0, E = Ty->getNumContainedTypes(); I != E; ++I) {
+    addTrivialMapRecursively(Ty->getContainedType(I));
+  }
+}
+
 void TypeMapTy::linkDefinedTypeBodies() {
   SmallVector<Type*, 16> Elements;
   for (StructType *SrcSTy : SrcDefinitionsToResolve) {