1 files changed, 4 insertions, 1 deletions
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/types.fail.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/types.fail.cpp
index 56fbc90a63d..ffe14ca8911 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/types.fail.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/types.fail.cpp
@@ -8,9 +8,12 @@
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++98, c++03
-
 // UNSUPPORTED: libcpp-has-no-threads
 
+// Before GCC 6, aggregate initialization kicks in.
+// See https://stackoverflow.com/q/41799015/627587.
+// UNSUPPORTED: gcc-4, gcc-5
+
 // <mutex>
 
 // struct defer_lock_t { explicit defer_lock_t() = default; };