diff --git a/llvm/utils/gn/secondary/libcxx/include/BUILD.gn b/llvm/utils/gn/secondary/libcxx/include/BUILD.gn
index 3349edeb3af05..5ea6f2a1595f7 100644
--- a/llvm/utils/gn/secondary/libcxx/include/BUILD.gn
+++ b/llvm/utils/gn/secondary/libcxx/include/BUILD.gn
@@ -298,6 +298,7 @@ if (current_toolchain == default_toolchain) {
       "__iterator/iter_swap.h",
       "__iterator/iterator.h",
       "__iterator/iterator_traits.h",
+      "__iterator/mergeable.h",
       "__iterator/move_iterator.h",
       "__iterator/next.h",
       "__iterator/ostream_iterator.h",