diff --git a/llvm/lib/Support/Host.cpp b/llvm/lib/Support/Host.cpp
index 5a55e55..f480a24 100644
--- a/llvm/lib/Support/Host.cpp
+++ b/llvm/lib/Support/Host.cpp
@@ -30,7 +30,7 @@
 #ifdef LLVM_ON_UNIX
 #include "Unix/Host.inc"
 #endif
-#ifdef LLVM_ON_WIN32
+#ifdef _WIN32
 #include "Windows/Host.inc"
 #endif
 #ifdef _MSC_VER