diff --git a/llvm/lib/Support/FileOutputBuffer.cpp b/llvm/lib/Support/FileOutputBuffer.cpp
index 57e5a8d..731740d 100644
--- a/llvm/lib/Support/FileOutputBuffer.cpp
+++ b/llvm/lib/Support/FileOutputBuffer.cpp
@@ -57,6 +57,8 @@
         // FIXME: In posix, you use the access() call to check this.
       }
       break;
+    case sys::fs::file_type::directory_file:
+      return errc::is_a_directory;
     default:
       if (EC)
         return EC;