diff --git a/glib/gatomic.h b/glib/gatomic.h
index 646a30df4..6bf41bb74 100644
--- a/glib/gatomic.h
+++ b/glib/gatomic.h
@@ -85,9 +85,7 @@ G_END_DECLS
 #if defined(G_ATOMIC_LOCK_FREE) && defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
 
 /* We prefer the new C11-style atomic extension of GCC if available */
-/* FIXME: Temporarily disabled on FreeBSD due to CI failures:
- * https://gitlab.gnome.org/GNOME/glib/issues/1940 */
-#if defined(__ATOMIC_SEQ_CST) && !defined(__FreeBSD__)
+#if defined(__ATOMIC_SEQ_CST)
 
 #define g_atomic_int_get(atomic) \
   (G_GNUC_EXTENSION ({                                                       \
@@ -187,6 +185,7 @@ G_END_DECLS
 
 #define g_atomic_pointer_compare_and_exchange(atomic, oldval, newval) \
   (G_GNUC_EXTENSION ({                                                       \
+    G_STATIC_ASSERT (sizeof (oldval) == sizeof (gpointer));                  \
     __typeof__ ((oldval)) gapcae_oldval = (oldval);                          \
     G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer));                 \
     (void) (0 ? (gpointer) *(atomic) : NULL);                                \
diff --git a/glib/tests/atomic.c b/glib/tests/atomic.c
index 5926e3135..3ba7d553f 100644
--- a/glib/tests/atomic.c
+++ b/glib/tests/atomic.c
@@ -83,14 +83,14 @@ test_types (void)
   res = g_atomic_pointer_compare_and_exchange (&vp, &s, &s);
   g_assert_false (res);
   g_assert_true (vp == 0);
-  res = g_atomic_pointer_compare_and_exchange (&vp, 0, 0);
+  res = g_atomic_pointer_compare_and_exchange (&vp, NULL, NULL);
   g_assert_true (res);
   g_assert_true (vp == 0);
 
   g_atomic_pointer_set (&ip, 0);
   ip2 = g_atomic_pointer_get (&ip);
   g_assert_true (ip2 == 0);
-  res = g_atomic_pointer_compare_and_exchange (&ip, 0, 0);
+  res = g_atomic_pointer_compare_and_exchange (&ip, NULL, NULL);
   g_assert_true (res);
   g_assert_true (ip == 0);
 
@@ -98,7 +98,7 @@ test_types (void)
   vp2 = (gpointer) g_atomic_pointer_get (&gs);
   gs2 = (gsize) vp2;
   g_assert_cmpuint (gs2, ==, 0);
-  res = g_atomic_pointer_compare_and_exchange (&gs, 0, 0);
+  res = g_atomic_pointer_compare_and_exchange (&gs, NULL, NULL);
   g_assert_true (res);
   g_assert_cmpuint (gs, ==, 0);
   gs2 = (gsize) g_atomic_pointer_add (&gs, 5);
@@ -191,14 +191,14 @@ G_GNUC_END_IGNORE_DEPRECATIONS
   res = g_atomic_pointer_compare_and_exchange (&vp, &s, &s);
   g_assert_false (res);
   g_assert_true (vp == 0);
-  res = g_atomic_pointer_compare_and_exchange (&vp, 0, 0);
+  res = g_atomic_pointer_compare_and_exchange (&vp, NULL, NULL);
   g_assert_true (res);
   g_assert_true (vp == 0);
 
   g_atomic_pointer_set (&ip, 0);
   ip2 = g_atomic_pointer_get (&ip);
   g_assert_true (ip2 == 0);
-  res = g_atomic_pointer_compare_and_exchange (&ip, 0, 0);
+  res = g_atomic_pointer_compare_and_exchange (&ip, NULL, NULL);
   g_assert_true (res);
   g_assert_true (ip == 0);
 
@@ -206,7 +206,7 @@ G_GNUC_END_IGNORE_DEPRECATIONS
   vp = g_atomic_pointer_get (&gs);
   gs2 = (gsize) vp;
   g_assert_cmpuint (gs2, ==, 0);
-  res = g_atomic_pointer_compare_and_exchange (&gs, 0, 0);
+  res = g_atomic_pointer_compare_and_exchange (&gs, NULL, NULL);
   g_assert_true (res);
   g_assert_cmpuint (gs, ==, 0);
   gs2 = (gsize) g_atomic_pointer_add (&gs, 5);