diff --git a/llvm/lib/LTO/LTO.cpp b/llvm/lib/LTO/LTO.cpp
index 21cad1de0ced57..5c603ac6ab4728 100644
--- a/llvm/lib/LTO/LTO.cpp
+++ b/llvm/lib/LTO/LTO.cpp
@@ -199,13 +199,19 @@ void llvm::computeLTOCacheKey(
              [](const ImportModule &Lhs, const ImportModule &Rhs) -> bool {
                return Lhs.getHash() < Rhs.getHash();
              });
+  std::vector<uint64_t> ImportedGUIDs;
   for (const ImportModule &Entry : ImportModulesVector) {
     auto ModHash = Entry.getHash();
     Hasher.update(ArrayRef<uint8_t>((uint8_t *)&ModHash[0], sizeof(ModHash)));
 
     AddUint64(Entry.getFunctions().size());
+
+    ImportedGUIDs.clear();
     for (auto &Fn : Entry.getFunctions())
-      AddUint64(Fn);
+      ImportedGUIDs.push_back(Fn);
+    llvm::sort(ImportedGUIDs);
+    for (auto &GUID : ImportedGUIDs)
+      AddUint64(GUID);
   }
 
   // Include the hash for the resolved ODR.