Index: llvm/include/llvm/IR/DerivedTypes.h
===================================================================
--- llvm/include/llvm/IR/DerivedTypes.h
+++ llvm/include/llvm/IR/DerivedTypes.h
@@ -269,6 +269,10 @@
     return create(StructFields, Name);
   }
 
+  /// This static method returns a StructType by that name if one exists, and a
+  /// null pointer otherwise.
+  static StructType *getIfExists(LLVMContext &Context, StringRef Name);
+
   /// This static method is the primary way to create a literal StructType.
   static StructType *get(LLVMContext &Context, ArrayRef<Type*> Elements,
                          bool isPacked = false);
Index: llvm/lib/Bitcode/Reader/BitcodeReader.cpp
===================================================================
--- llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -1543,6 +1543,14 @@
   return parseTypeTableBody();
 }
 
+static StructType *findMatchingStructType(LLVMContext &Context, StringRef Name,
+                                          ArrayRef<Type *> EltTys) {
+  StructType *Candidate = StructType::getIfExists(Context, Name);
+  if (Candidate && EltTys.equals(Candidate->elements()))
+    return Candidate;
+  return nullptr;
+}
+
 Error BitcodeReader::parseTypeTableBody() {
   if (!TypeList.empty())
     return error("Invalid multiple blocks");
@@ -1709,25 +1717,33 @@
       if (NumRecords >= TypeList.size())
         return error("Invalid TYPE table");
 
-      // Check to see if this was forward referenced, if so fill in the temp.
-      StructType *Res = cast_or_null<StructType>(TypeList[NumRecords]);
-      if (Res) {
-        Res->setName(TypeName);
-        TypeList[NumRecords] = nullptr;
-      } else  // Otherwise, create a new struct.
-        Res = createIdentifiedStructType(Context, TypeName);
-      TypeName.clear();
-
-      SmallVector<Type*, 8> EltTys;
+      SmallVector<Type *, 8> EltTys;
       for (unsigned i = 1, e = Record.size(); i != e; ++i) {
         if (Type *T = getTypeByID(Record[i]))
           EltTys.push_back(T);
         else
           break;
       }
-      if (EltTys.size() != Record.size()-1)
+      if (EltTys.size() != Record.size() - 1)
         return error("Invalid record");
-      Res->setBody(EltTys, Record[0]);
+
+      // Check to see if this was forward referenced, if so fill in the temp.
+      StructType *Res = cast_or_null<StructType>(TypeList[NumRecords]);
+      if (Res) {
+        Res->setName(TypeName);
+        TypeList[NumRecords] = nullptr;
+        Res->setBody(EltTys, Record[0]);
+      } else {
+        // If it was not, check so see whether the context already contains that
+        // type, and create it if necessary
+        Res = findMatchingStructType(Context, TypeName, EltTys);
+        if (!Res) {
+          Res = createIdentifiedStructType(Context, TypeName);
+          Res->setBody(EltTys, Record[0]);
+        }
+      }
+      TypeName.clear();
+
       ResultTy = Res;
       break;
     }
Index: llvm/lib/IR/Type.cpp
===================================================================
--- llvm/lib/IR/Type.cpp
+++ llvm/lib/IR/Type.cpp
@@ -336,8 +336,16 @@
 //                       StructType Implementation
 //===----------------------------------------------------------------------===//
 
+StructType *StructType::getIfExists(LLVMContext &Context, StringRef Name) {
+  auto I = Context.pImpl->NamedStructTypes.find(Name);
+  if (I == Context.pImpl->NamedStructTypes.end())
+    return nullptr;
+  return I->getValue();
+}
+
 // Primitive Constructors.
 
+
 StructType *StructType::get(LLVMContext &Context, ArrayRef<Type*> ETypes,
                             bool isPacked) {
   LLVMContextImpl *pImpl = Context.pImpl;
Index: llvm/unittests/Bitcode/BitReaderTest.cpp
===================================================================
--- llvm/unittests/Bitcode/BitReaderTest.cpp
+++ llvm/unittests/Bitcode/BitReaderTest.cpp
@@ -190,4 +190,46 @@
   EXPECT_FALSE(verifyModule(*M, &dbgs()));
 }
 
+TEST(BitReaderTest, UseExistingNameStructType) {
+  // Make a module using a struct type, then write that.
+  LLVMContext C1;
+  StructType *T1 = StructType::create(C1, "Correct");
+  T1->setBody(Type::getInt32Ty(C1));
+  std::unique_ptr<Module> M1(new Module("M1", C1));
+  M1->getOrInsertFunction("F1", T1);
+  SmallString<1024> Memory;
+  raw_svector_ostream OS(Memory);
+  WriteBitcodeToFile(*M1, OS);
+
+  // Define that struct type in a new context. Read the module into that
+  // context. At this point, the context contains the StructType the module
+  // uses.
+  LLVMContext C2;
+  StructType *T2 = StructType::create(C2, T1->getName());
+  T2->setBody(Type::getInt32Ty(C2));
+  auto Careful = parseBitcodeFile(MemoryBufferRef(Memory.str(), "test"), C2);
+  EXPECT_TRUE((bool)Careful);
+  std::unique_ptr<Module> M2(Careful.get().release());
+
+  // Then one single test: was the already-present struct type used?
+  Function *F2 = M2->getFunction("F1");
+  EXPECT_NE(F2, nullptr);
+  EXPECT_EQ(cast<StructType>(F2->getReturnType())->getName(), T1->getName());
+
+  // Define a different StructType of the same name, then read the bitcode into
+  // THAT context.
+  LLVMContext C3;
+  StructType *T3 = StructType::create(C3, T1->getName());
+  T3->setBody(Type::getFloatTy(C3));
+  Careful = parseBitcodeFile(MemoryBufferRef(Memory.str(), "test"), C3);
+  EXPECT_TRUE((bool)Careful);
+  std::unique_ptr<Module> M3(Careful.get().release());
+
+  // The same test: Was the already-present struct type used? It should not be
+  // used, since its structure differs.
+  Function *F3 = M3->getFunction("F1");
+  EXPECT_NE(F3, nullptr);
+  EXPECT_NE(cast<StructType>(F3->getReturnType())->getName(), T1->getName());
+}
+
 } // end namespace