diff --git a/clang/lib/Basic/FileManager.cpp b/clang/lib/Basic/FileManager.cpp
index 45c4bf0..6fc00d9 100644
--- a/clang/lib/Basic/FileManager.cpp
+++ b/clang/lib/Basic/FileManager.cpp
@@ -157,7 +157,7 @@
       DirName != llvm::sys::path::root_path(DirName) &&
       llvm::sys::path::is_separator(DirName.back()))
     DirName = DirName.substr(0, DirName.size()-1);
-#ifdef LLVM_ON_WIN32
+#ifdef _WIN32
   // Fixing a problem with "clang C:test.c" on Windows.
   // Stat("C:") does not recognize "C:" as a valid directory
   std::string DirNameStr;