diff --git a/libstdc++-v3/include/std/mutex b/libstdc++-v3/include/std/mutex
index e575a81c138..631c38069d4 100644
--- a/libstdc++-v3/include/std/mutex
+++ b/libstdc++-v3/include/std/mutex
@@ -190,7 +190,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	  return static_cast<_Derived*>(this)->_M_timedlock(__ts);
 	}
 
-#ifdef _GLIBCXX_USE_PTHREAD_MUTEX_CLOCKLOCK
+#if _GLIBCXX_USE_PTHREAD_MUTEX_CLOCKLOCK
       template<typename _Duration>
 	bool
 	_M_try_lock_until(const chrono::time_point<chrono::steady_clock,
@@ -377,7 +377,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       _M_timedlock(const __gthread_time_t& __ts)
       { return !__gthread_recursive_mutex_timedlock(&_M_mutex, &__ts); }
 
-#ifdef _GLIBCXX_USE_PTHREAD_MUTEX_CLOCKLOCK
+#if _GLIBCXX_USE_PTHREAD_MUTEX_CLOCKLOCK
       bool
       _M_clocklock(clockid_t __clockid, const __gthread_time_t& __ts)
       { return !pthread_mutex_clocklock(&_M_mutex, __clockid, &__ts); }
diff --git a/libstdc++-v3/testsuite/30_threads/timed_mutex/121496.cc b/libstdc++-v3/testsuite/30_threads/timed_mutex/121496.cc
new file mode 100644
index 00000000000..d919704b135
--- /dev/null
+++ b/libstdc++-v3/testsuite/30_threads/timed_mutex/121496.cc
@@ -0,0 +1,14 @@
+// { dg-do compile { target { { i?86-*-linux* x86_64-*-linux* } && lp64 } } }
+// { dg-require-effective-target c++11 }
+// { dg-options "-fsanitize=thread" }
+
+// PR libstdc++/121496 no member named '_M_clocklock' with -fsanitize=thread
+
+#include <mutex>
+#include <chrono>
+
+void
+test_pr121496(std::timed_mutex& m)
+{
+  (void) m.try_lock_until(std::chrono::steady_clock::time_point{});
+}