diff --git a/glib/tests/timer.c b/glib/tests/timer.c
index 42ed5a9..243563e 100644
--- a/glib/tests/timer.c
+++ b/glib/tests/timer.c
@@ -30,7 +30,7 @@ static void
 test_timer_basic (void)
 {
   GTimer *timer;
-  gdouble elapsed;
+  volatile gdouble elapsed;
   gulong micros;
 
   timer = g_timer_new ();
@@ -65,7 +65,7 @@ static void
 test_timer_stop (void)
 {
   GTimer *timer;
-  gdouble elapsed, elapsed2;
+  volatile gdouble elapsed, elapsed2;
 
   timer = g_timer_new ();