diff --git a/llvm/lib/Object/ArchiveWriter.cpp b/llvm/lib/Object/ArchiveWriter.cpp
index 28955e1..1a0137e 100644
--- a/llvm/lib/Object/ArchiveWriter.cpp
+++ b/llvm/lib/Object/ArchiveWriter.cpp
@@ -207,7 +207,7 @@
   for (auto ToE = sys::path::end(To); ToI != ToE; ++ToI)
     sys::path::append(Relative, *ToI);
 
-#ifdef LLVM_ON_WIN32
+#ifdef _WIN32
   // Replace backslashes with slashes so that the path is portable between *nix
   // and Windows.
   std::replace(Relative.begin(), Relative.end(), '\\', '/');