Index: libcxx/test/libcxx/atomics/atomics.align/align.pass.pass.cpp
===================================================================
--- libcxx/test/libcxx/atomics/atomics.align/align.pass.pass.cpp
+++ libcxx/test/libcxx/atomics/atomics.align/align.pass.pass.cpp
@@ -13,6 +13,10 @@
 // std::atomic when used with __attribute__((vector(X))).
 // XFAIL: gcc
 
+// AIX currently fails becase it does not support 16-byte MaxAtomicPromoteWidth
+// while the type is implied to be lock-free.
+// XFAIL: aix
+
 // <atomic>
 
 // Verify that the content of atomic<T> is properly aligned if the type is