diff --git a/libnm-core/tests/test-general.c b/libnm-core/tests/test-general.c
index e64f1b2b44..53847b72a3 100644
--- a/libnm-core/tests/test-general.c
+++ b/libnm-core/tests/test-general.c
@@ -3493,7 +3493,7 @@ test_setting_compare_addresses (void)
 	nm_ip_address_unref (a);
 
 	if (nmtst_get_rand_uint32 () % 2)
-		NMTST_SWAP (s1, s2);
+		NM_SWAP (s1, s2);
 
 	success = nm_setting_compare (s1, s2, NM_SETTING_COMPARE_FLAG_EXACT);
 	g_assert (!success);
@@ -3525,7 +3525,7 @@ test_setting_compare_routes (void)
 	nm_ip_route_unref (r);
 
 	if (nmtst_get_rand_uint32 () % 2)
-		NMTST_SWAP (s1, s2);
+		NM_SWAP (s1, s2);
 
 	success = nm_setting_compare (s1, s2, NM_SETTING_COMPARE_FLAG_EXACT);
 	g_assert (!success);
@@ -6820,7 +6820,7 @@ _team_config_equal_check (const char *conf1,
 	gboolean is_same;
 
 	if (nmtst_get_rand_bool ())
-		NMTST_SWAP (conf1, conf2);
+		NM_SWAP (conf1, conf2);
 
 	if (!nm_streq0 (conf1, conf2)) {
 		_team_config_equal_check (conf1, conf1, port_config, TRUE);
diff --git a/shared/nm-glib-aux/nm-macros-internal.h b/shared/nm-glib-aux/nm-macros-internal.h
index d54bb3ddda..758a4ec9aa 100644
--- a/shared/nm-glib-aux/nm-macros-internal.h
+++ b/shared/nm-glib-aux/nm-macros-internal.h
@@ -757,6 +757,17 @@ NM_G_ERROR_MSG (GError *error)
 
 /*****************************************************************************/
 
+#define NM_SWAP(a, b) \
+	G_STMT_START { \
+		typeof (a) _tmp; \
+		\
+		_tmp = (a); \
+		(a) = (b); \
+		(b) = _tmp; \
+	} G_STMT_END
+
+/*****************************************************************************/
+
 static inline gboolean
 _NM_IN_STRSET_streq (const char *x, const char *s)
 {
diff --git a/shared/nm-glib-aux/tests/test-shared-general.c b/shared/nm-glib-aux/tests/test-shared-general.c
index 28aff95c02..54a96ecb5b 100644
--- a/shared/nm-glib-aux/tests/test-shared-general.c
+++ b/shared/nm-glib-aux/tests/test-shared-general.c
@@ -296,7 +296,7 @@ _strv_cmp_fuzz_input (const char *const*in,
 	if (nmtst_get_rand_bool ()) {
 		/* randomly swap the original and the clone. That means, out_s1 is either
 		 * the input argument (as-is) or the sementically equal clone. */
-		NMTST_SWAP (*out_s1, *out_s2);
+		NM_SWAP (*out_s1, *out_s2);
 	}
 	if (nmtst_get_rand_bool ()) {
 		/* randomly make s1 and s2 the same. This is for testing that
diff --git a/shared/nm-utils/nm-test-utils.h b/shared/nm-utils/nm-test-utils.h
index adf2ba1b35..881fdcf89c 100644
--- a/shared/nm-utils/nm-test-utils.h
+++ b/shared/nm-utils/nm-test-utils.h
@@ -1272,15 +1272,6 @@ nmtst_uuid_generate (void)
 
 #endif
 
-#define NMTST_SWAP(x, y) \
-	G_STMT_START { \
-		char __nmtst_swap_temp[sizeof((x)) == sizeof((y)) ? (signed) sizeof((x)) : -1]; \
-		\
-		memcpy(__nmtst_swap_temp, &(y),              sizeof (__nmtst_swap_temp)); \
-		memcpy(&(y),              &(x),              sizeof (__nmtst_swap_temp)); \
-		memcpy(&(x),              __nmtst_swap_temp, sizeof (__nmtst_swap_temp)); \
-	} G_STMT_END
-
 #define nmtst_assert_str_has_substr(str, substr) \
 	G_STMT_START { \
 		const char *__str = (str); \
@@ -2087,14 +2078,14 @@ nmtst_assert_setting_is_equal (gconstpointer /* const NMSetting * */ a,
 	g_assert (NM_IS_SETTING (b));
 
 	if (NM_FLAGS_HAS (r, 0x4))
-		NMTST_SWAP (a, b);
+		NM_SWAP (a, b);
 
 	g_assert (nm_setting_compare ((NMSetting *) a,
 	                              (NMSetting *) b,
 	                              flags));
 
 	if (NM_FLAGS_HAS (r, 0x8))
-		NMTST_SWAP (a, b);
+		NM_SWAP (a, b);
 
 	g_assert (nm_setting_diff ((NMSetting *) a,
 	                           (NMSetting *) b,
diff --git a/src/platform/nm-platform.c b/src/platform/nm-platform.c
index 699c8902fa..9bbc37453c 100644
--- a/src/platform/nm-platform.c
+++ b/src/platform/nm-platform.c
@@ -3831,23 +3831,39 @@ delete_and_next2:
 	return TRUE;
 }
 
-static guint
-ip6_address_scope_priority (const struct in6_addr *addr)
+typedef enum {
+	IP6_ADDR_SCOPE_LOOPBACK,
+	IP6_ADDR_SCOPE_LINKLOCAL,
+	IP6_ADDR_SCOPE_SITELOCAL,
+	IP6_ADDR_SCOPE_OTHER,
+} IP6AddrScope;
+
+static IP6AddrScope
+ip6_address_scope (const NMPlatformIP6Address *a)
 {
-	if (IN6_IS_ADDR_LINKLOCAL (addr))
-		return 1;
-	if (IN6_IS_ADDR_SITELOCAL (addr))
-		return 2;
-	return 3;
+	if (IN6_IS_ADDR_LOOPBACK (&a->address))
+		return IP6_ADDR_SCOPE_LOOPBACK;
+	if (IN6_IS_ADDR_LINKLOCAL (&a->address))
+		return IP6_ADDR_SCOPE_LINKLOCAL;
+	if (IN6_IS_ADDR_SITELOCAL (&a->address))
+		return IP6_ADDR_SCOPE_SITELOCAL;
+	return IP6_ADDR_SCOPE_OTHER;
 }
 
 static int
-ip6_address_scope_cmp (gconstpointer a, gconstpointer b)
+ip6_address_scope_cmp (gconstpointer p_a, gconstpointer p_b, gpointer increasing)
 {
-	const NMPlatformIP6Address *x = NMP_OBJECT_CAST_IP6_ADDRESS (*(const void **) a);
-	const NMPlatformIP6Address *y = NMP_OBJECT_CAST_IP6_ADDRESS (*(const void **) b);
+	const NMPlatformIP6Address *a;
+	const NMPlatformIP6Address *b;
 
-	return ip6_address_scope_priority (&x->address) - ip6_address_scope_priority (&y->address);
+	if (!increasing)
+		NM_SWAP (p_a, p_b);
+
+	a = NMP_OBJECT_CAST_IP6_ADDRESS (*(const NMPObject *const*) p_a);
+	b = NMP_OBJECT_CAST_IP6_ADDRESS (*(const NMPObject *const*) p_b);
+
+	NM_CMP_DIRECT (ip6_address_scope (a), ip6_address_scope (b));
+	return 0;
 }
 
 /**
@@ -3888,7 +3904,7 @@ nm_platform_ip6_address_sync (NMPlatform *self,
 	 * apply the same sorting to known addresses, so that we don't try to
 	 * unnecessary change the order of addresses with different scopes. */
 	if (known_addresses)
-		g_ptr_array_sort (known_addresses, ip6_address_scope_cmp);
+		g_ptr_array_sort_with_data (known_addresses, ip6_address_scope_cmp, GINT_TO_POINTER (TRUE));
 
 	if (!_addr_array_clean_expired (AF_INET6, ifindex, known_addresses, now, &known_addresses_idx))
 		known_addresses = NULL;
@@ -3903,6 +3919,10 @@ nm_platform_ip6_address_sync (NMPlatform *self,
 
 	if (plat_addresses) {
 		guint known_addresses_len;
+		IP6AddrScope cur_scope;
+		gboolean delete_remaining_addrs;
+
+		g_ptr_array_sort_with_data (plat_addresses, ip6_address_scope_cmp, GINT_TO_POINTER (FALSE));
 
 		known_addresses_len = known_addresses ? known_addresses->len : 0;
 
@@ -3954,38 +3974,54 @@ clear_and_next:
 		 * selection will choose addresses in the order as they are reported by kernel.
 		 * Note that the order in @plat_addresses of the remaining matches is highest
 		 * priority first.
-		 * We need to compare this to the order in @known_addresses (which has lowest
-		 * priority first).
+		 * We need to compare this to the order of addresses with same scope in
+		 * @known_addresses (which has lowest priority first).
 		 *
 		 * If we find a first discrepancy, we need to delete all remaining addresses
-		 * from that point on, because below we must re-add all the addresses in the
-		 * right order to get their priority right. */
+		 * with same scope from that point on, because below we must re-add all the
+		 * addresses in the right order to get their priority right. */
+		cur_scope = IP6_ADDR_SCOPE_LOOPBACK;
+		delete_remaining_addrs = FALSE;
 		i_plat = plat_addresses->len;
 		i_know = 0;
 		while (i_plat > 0) {
 			const NMPlatformIP6Address *plat_addr = NMP_OBJECT_CAST_IP6_ADDRESS (plat_addresses->pdata[--i_plat]);
+			IP6AddrScope plat_scope;
 
 			if (!plat_addr)
 				continue;
 
-			for (; i_know < known_addresses_len; i_know++) {
-				const NMPlatformIP6Address *know_addr = NMP_OBJECT_CAST_IP6_ADDRESS (known_addresses->pdata[i_know]);
+			plat_scope = ip6_address_scope (plat_addr);
+			if (cur_scope != plat_scope) {
+				nm_assert (cur_scope < plat_scope);
+				delete_remaining_addrs = FALSE;
+				cur_scope = plat_scope;
+			}
 
-				if (!know_addr)
-					continue;
+			if (!delete_remaining_addrs) {
+				delete_remaining_addrs = TRUE;
+				for (; i_know < known_addresses_len; i_know++) {
+					const NMPlatformIP6Address *know_addr = NMP_OBJECT_CAST_IP6_ADDRESS (known_addresses->pdata[i_know]);
+					IP6AddrScope know_scope;
 
-				if (IN6_ARE_ADDR_EQUAL (&plat_addr->address, &know_addr->address)) {
-					/* we have a match. Mark address as handled. */
-					i_know++;
-					goto next_plat;
+					if (!know_addr)
+						continue;
+
+					know_scope = ip6_address_scope (know_addr);
+					if (know_scope < plat_scope)
+						continue;
+
+					if (IN6_ARE_ADDR_EQUAL (&plat_addr->address, &know_addr->address)) {
+						/* we have a match. Mark address as handled. */
+						i_know++;
+						delete_remaining_addrs = FALSE;
+						goto next_plat;
+					}
+
+					/* plat_address has no match. Now delete_remaining_addrs is TRUE and we will
+					 * delete all the remaining addresses with cur_scope. */
+					break;
 				}
-
-				/* all remainging addresses need to be removed as well, so that we can
-				 * re-add them in the correct order. Signal that, by setting @i_know
-				 * so that the next @i_plat iteration, we won't enter the loop and
-				 * delete the address right away */
-				i_know = known_addresses_len;
-				break;
 			}
 
 			nm_platform_ip6_address_delete (self, ifindex, plat_addr->address, plat_addr->plen);
diff --git a/src/platform/tests/test-route.c b/src/platform/tests/test-route.c
index 707313b4ca..f074ca69cf 100644
--- a/src/platform/tests/test-route.c
+++ b/src/platform/tests/test-route.c
@@ -1239,7 +1239,7 @@ again_uid_range:
 	rr->uid_range.end   = nmtst_rand_select (0u, uids.uid, uids.euid);
 	if (rr->uid_range_has) {
 		if (rr->uid_range.end < rr->uid_range.start)
-			NMTST_SWAP (rr->uid_range.start, rr->uid_range.end);
+			NM_SWAP (rr->uid_range.start, rr->uid_range.end);
 		if (   rr->uid_range.start == ((guint32) -1)
 		    || rr->uid_range.end   == ((guint32) -1))
 			goto again_uid_range;
@@ -1259,7 +1259,7 @@ again_uid_range:
 				range->start = nmtst_rand_select (1u, 0xFFFEu, ((p      ) % 0xFFFEu) + 1);
 				range->end   = nmtst_rand_select (1u, 0xFFFEu, ((p >> 16) % 0xFFFEu) + 1, range->start);
 				if (range->end < range->start)
-					NMTST_SWAP (range->start, range->end);
+					NM_SWAP (range->start, range->end);
 			}
 		}
 	}
diff --git a/src/tests/test-core.c b/src/tests/test-core.c
index 590f7c36a5..b90a8fac69 100644
--- a/src/tests/test-core.c
+++ b/src/tests/test-core.c
@@ -1019,7 +1019,7 @@ _test_connection_sort_autoconnect_priority_one (NMConnection **list, gboolean sh
 	if (shuffle) {
 		for (i = count - 1; i > 0; i--) {
 			j = g_rand_int (nmtst_get_rand ()) % (i + 1);
-			NMTST_SWAP (connections->pdata[i], connections->pdata[j]);
+			NM_SWAP (connections->pdata[i], connections->pdata[j]);
 		}
 	}
 
diff --git a/src/tests/test-ip6-config.c b/src/tests/test-ip6-config.c
index 401d1eee06..efc329832d 100644
--- a/src/tests/test-ip6-config.c
+++ b/src/tests/test-ip6-config.c
@@ -246,7 +246,7 @@ test_nm_ip6_config_addresses_sort_check (NMIP6Config *config, NMSettingIP6Config
 		for (i = 0; i < addr_count; i++) {
 			int j = g_rand_int_range (nmtst_get_rand (), i, addr_count);
 
-			NMTST_SWAP (idx[i], idx[j]);
+			NM_SWAP (idx[i], idx[j]);
 			nm_ip6_config_add_address (copy, _nmtst_ip6_config_get_address (config, idx[i]));
 		}