Index: lib/Core/Reproduce.cpp
===================================================================
--- lib/Core/Reproduce.cpp
+++ lib/Core/Reproduce.cpp
@@ -52,9 +52,11 @@
 
 // Converts path to use unix path separators so the cpio can be extracted on
 // both unix and windows.
+#ifdef LLVM_ON_WIN32
 static void convertToUnixPathSeparator(SmallString<128> &Path) {
   std::replace(Path.begin(), Path.end(), '\\', '/');
 }
+#endif
 
 void CpioFile::append(StringRef Path, StringRef Data) {
   if (!Seen.insert(Path).second)
@@ -65,7 +67,10 @@
   // (i.e. in that case we are creating baz.cpio.)
   SmallString<128> Fullpath;
   path::append(Fullpath, Basename, Path);
+
+#ifdef LLVM_ON_WIN32
   convertToUnixPathSeparator(Fullpath);
+#endif
 
   writeMember(*OS, Fullpath, Data);