Index: lib/Driver/Driver.cpp
===================================================================
--- lib/Driver/Driver.cpp
+++ lib/Driver/Driver.cpp
@@ -1972,7 +1972,7 @@
     }
   }
 
-  if (llvm::sys::fs::exists(Twine(Path)))
+  if (D.getVFS().exists(Path))
     return true;
 
   if (D.IsCLMode()) {
Index: lib/Tooling/Tooling.cpp
===================================================================
--- lib/Tooling/Tooling.cpp
+++ lib/Tooling/Tooling.cpp
@@ -303,8 +303,6 @@
 
   const std::unique_ptr<driver::Driver> Driver(
       newDriver(&Diagnostics, BinaryName, Files->getVirtualFileSystem()));
-  // Since the input might only be virtual, don't check whether it exists.
-  Driver->setCheckInputsExist(false);
   const std::unique_ptr<driver::Compilation> Compilation(
       Driver->BuildCompilation(llvm::makeArrayRef(Argv)));
   if (!Compilation)