diff --git a/llvm/utils/gn/secondary/libcxx/src/BUILD.gn b/llvm/utils/gn/secondary/libcxx/src/BUILD.gn
index 5e0cc6f3831b7c..9ca9d1bc8dd07b 100644
--- a/llvm/utils/gn/secondary/libcxx/src/BUILD.gn
+++ b/llvm/utils/gn/secondary/libcxx/src/BUILD.gn
@@ -115,6 +115,8 @@ config("cxx_config") {
 cxx_sources = [
   "algorithm.cpp",
   "any.cpp",
+  "atomic.cpp",
+  "barrier.cpp",
   "bind.cpp",
   "charconv.cpp",
   "chrono.cpp",