diff --git a/llvm/utils/gn/secondary/libcxx/include/BUILD.gn b/llvm/utils/gn/secondary/libcxx/include/BUILD.gn
index 7e670c3d6e3e..e76ec39fbbc8 100644
--- a/llvm/utils/gn/secondary/libcxx/include/BUILD.gn
+++ b/llvm/utils/gn/secondary/libcxx/include/BUILD.gn
@@ -98,6 +98,7 @@ if (current_toolchain == default_toolchain) {
       "__ranges/access.h",
       "__ranges/concepts.h",
       "__ranges/enable_borrowed_range.h",
+      "__ranges/size.h",
       "__ranges/view.h",
       "__split_buffer",
       "__sso_allocator",