diff --git a/llvm/utils/gn/secondary/libcxx/include/BUILD.gn b/llvm/utils/gn/secondary/libcxx/include/BUILD.gn
index c9867ccc547ac..700f01b9c5c74 100644
--- a/llvm/utils/gn/secondary/libcxx/include/BUILD.gn
+++ b/llvm/utils/gn/secondary/libcxx/include/BUILD.gn
@@ -152,10 +152,12 @@ if (current_toolchain == default_toolchain) {
       "__algorithm/pstl_backends/cpu_backends/find_if.h",
       "__algorithm/pstl_backends/cpu_backends/for_each.h",
       "__algorithm/pstl_backends/cpu_backends/serial.h",
+      "__algorithm/pstl_backends/cpu_backends/transform.h",
       "__algorithm/pstl_fill.h",
       "__algorithm/pstl_find.h",
       "__algorithm/pstl_for_each.h",
       "__algorithm/pstl_frontend_dispatch.h",
+      "__algorithm/pstl_transform.h",
       "__algorithm/push_heap.h",
       "__algorithm/ranges_adjacent_find.h",
       "__algorithm/ranges_all_of.h",