diff --git a/llvm/lib/Support/Unix/Path.inc b/llvm/lib/Support/Unix/Path.inc
--- a/llvm/lib/Support/Unix/Path.inc
+++ b/llvm/lib/Support/Unix/Path.inc
@@ -409,8 +409,15 @@
   StringRef p = path.toNullTerminatedStringRef(path_storage);
 
   if (::mkdir(p.begin(), Perms) == -1) {
-    if (errno != EEXIST || !IgnoreExisting)
-      return std::error_code(errno, std::generic_category());
+    if (errno == EEXIST && IgnoreExisting) {
+      // Only ignore existing directory.
+      bool is_dir;
+      if (std::error_code ec = is_directory(p, is_dir))
+        return ec;
+      if (is_dir)
+        return std::error_code();
+    }
+    return std::error_code(errno, std::generic_category());
   }
 
   return std::error_code();
diff --git a/llvm/unittests/Support/Path.cpp b/llvm/unittests/Support/Path.cpp
--- a/llvm/unittests/Support/Path.cpp
+++ b/llvm/unittests/Support/Path.cpp
@@ -1012,6 +1012,14 @@
 
   // Restore umask to be safe.
   ::umask(OldUmask);
+
+  // Test create directory on top of a file.
+  int FD;
+  SmallString<64> TempPath;
+  ASSERT_NO_ERROR(fs::createTemporaryFile("prefix", "temp", FD, TempPath));
+  ::close(FD);
+  ASSERT_EQ(fs::create_directory(Twine(TempPath)), errc::file_exists);
+
 #endif
 
 #ifdef _WIN32