diff --git a/clang/unittests/Basic/FileManagerTest.cpp b/clang/unittests/Basic/FileManagerTest.cpp
index a2a6c6a..5b7a7db 100644
--- a/clang/unittests/Basic/FileManagerTest.cpp
+++ b/clang/unittests/Basic/FileManagerTest.cpp
@@ -31,7 +31,7 @@
   llvm::StringMap<FileData, llvm::BumpPtrAllocator> StatCalls;
 
   void InjectFileOrDirectory(const char *Path, ino_t INode, bool IsFile) {
-#ifndef LLVM_ON_WIN32
+#ifndef _WIN32
     SmallString<128> NormalizedPath(Path);
     llvm::sys::path::native(NormalizedPath);
     Path = NormalizedPath.c_str();
@@ -63,7 +63,7 @@
   LookupResult getStat(StringRef Path, FileData &Data, bool isFile,
                        std::unique_ptr<vfs::File> *F,
                        vfs::FileSystem &FS) override {
-#ifndef LLVM_ON_WIN32
+#ifndef _WIN32
     SmallString<128> NormalizedPath(Path);
     llvm::sys::path::native(NormalizedPath);
     Path = NormalizedPath.c_str();
@@ -143,7 +143,7 @@
   statCache->InjectDirectory("/tmp", 42);
   statCache->InjectFile("/tmp/test", 43);
 
-#ifdef LLVM_ON_WIN32
+#ifdef _WIN32
   const char *DirName = "C:.";
   const char *FileName = "C:test";
   statCache->InjectDirectory(DirName, 44);
@@ -161,7 +161,7 @@
   ASSERT_TRUE(dir != nullptr);
   EXPECT_EQ("/tmp", dir->getName());
 
-#ifdef LLVM_ON_WIN32
+#ifdef _WIN32
   file = manager.getFile(FileName);
   ASSERT_TRUE(file != NULL);
 
@@ -225,7 +225,7 @@
 
 // The following tests apply to Unix-like system only.
 
-#ifndef LLVM_ON_WIN32
+#ifndef _WIN32
 
 // getFile() returns the same FileEntry for real files that are aliases.
 TEST_F(FileManagerTest, getFileReturnsSameFileEntryForAliasedRealFiles) {
@@ -295,11 +295,11 @@
   EXPECT_EQ(123, file2->getSize());
 }
 
-#endif  // !LLVM_ON_WIN32
+#endif  // !_WIN32
 
 TEST_F(FileManagerTest, makeAbsoluteUsesVFS) {
   SmallString<64> CustomWorkingDir;
-#ifdef LLVM_ON_WIN32
+#ifdef _WIN32
   CustomWorkingDir = "C:";
 #else
   CustomWorkingDir = "/";