diff --git a/libcxx/include/bitset b/libcxx/include/bitset
index 06fd729ef8c4..aa7a596f6625 100644
--- a/libcxx/include/bitset
+++ b/libcxx/include/bitset
@@ -253,7 +253,7 @@ __bitset<_N_words, _Size>::__bitset(unsigned long long __v) _NOEXCEPT
     : __first_{__v}
 #elif __SIZE_WIDTH__ == 32
     : __first_{__v, __v >> __bits_per_word}
-#elif
+#else
 #error This constructor has not been ported to this platform
 #endif
 #endif