[PATCH] libstdc++: Fix UB in atomic_ref/wait_notify.cc [PR101761]

[Thomas Rodgers <rodgert@appliantology.com>]

From: Thomas Rodgers <rodgert@twrodgers.com>

Remove UB in atomic_ref/wait_notify test.

Signed-off-by: Thomas Rodgers <trodgers@redhat.com>

libstdc++-v3/ChangeLog:

	PR libstdc++/101761
	* testsuite/29_atomics/atomic_ref/wait_notify.cc (test): Use
	va and vb as arguments to wait/notify, remove unused bb local.

Tested x86_64-pc-linux-gnu, committed to master.
Ok to backport to releases/gcc-11?

---
 .../testsuite/29_atomics/atomic_ref/wait_notify.cc         | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/libstdc++-v3/testsuite/29_atomics/atomic_ref/wait_notify.cc b/libstdc++-v3/testsuite/29_atomics/atomic_ref/wait_notify.cc
index b75e27617f7..b41d1ac0bb7 100644
--- a/libstdc++-v3/testsuite/29_atomics/atomic_ref/wait_notify.cc
+++ b/libstdc++-v3/testsuite/29_atomics/atomic_ref/wait_notify.cc
@@ -33,15 +33,14 @@ template<typename S>
     if constexpr (std::atomic_ref<S>::is_always_lock_free)
     {
       S aa{ va };
-      S bb{ vb };
       std::atomic_ref<S> a{ aa };
-      a.wait(bb);
+      a.wait(vb);
       std::thread t([&]
         {
-	  a.store(bb);
+	  a.store(vb);
 	  a.notify_one();
         });
-      a.wait(aa);
+      a.wait(va);
       t.join();
     }
   }
-- 
2.31.1