Index: lib/Serialization/ASTReader.cpp
===================================================================
--- lib/Serialization/ASTReader.cpp
+++ lib/Serialization/ASTReader.cpp
@@ -8708,7 +8708,8 @@
   bool AllowConfigurationMismatch, bool ValidateSystemInputs,
   bool UseGlobalIndex,
   std::unique_ptr<llvm::Timer> ReadTimer)
-    : Listener(new PCHValidator(PP, *this)), DeserializationListener(nullptr),
+    : Listener(DisableValidation ? nullptr : new PCHValidator(PP, *this)),
+      DeserializationListener(nullptr),
       OwnsDeserializationListener(false), SourceMgr(PP.getSourceManager()),
       FileMgr(PP.getFileManager()), PCHContainerRdr(PCHContainerRdr),
       Diags(PP.getDiagnostics()), SemaObj(nullptr), PP(PP), Context(Context),