diff --git a/glib/ghash.c b/glib/ghash.c
index 40a0fb2ca8b77834fbe7320ee5ee245404a4d2c5..f3ed0f3b913d7345fd3042e853f5d3be43c54483 100644
--- a/glib/ghash.c
+++ b/glib/ghash.c
@@ -565,13 +565,12 @@ g_hash_table_remove_node (GHashTable   *hash_table,
 static void
 g_hash_table_setup_storage (GHashTable *hash_table)
 {
-  gboolean small;
+  gboolean small = FALSE;
 
   /* We want to use small arrays only if:
    *   - we are running on a system where that makes sense (64 bit); and
    *   - we are not running under valgrind.
    */
-  small = FALSE;
 
 #ifdef USE_SMALL_ARRAYS
   small = TRUE;
diff --git a/glib/tests/keyfile.c b/glib/tests/keyfile.c
index ccbdadd56751c9212fcc322b275e231189a4ca25..7530bc8c32aea0a373fd3a1089e61fc0df8d22af 100644
--- a/glib/tests/keyfile.c
+++ b/glib/tests/keyfile.c
@@ -1151,6 +1151,7 @@ test_key_names (void)
   check_error (&error,
                G_KEY_FILE_ERROR,
                G_KEY_FILE_ERROR_KEY_NOT_FOUND);
+  g_assert_null (value);
   g_key_file_free (keyfile);
 
   keyfile = g_key_file_new ();
@@ -1160,6 +1161,7 @@ test_key_names (void)
   check_error (&error,
                G_KEY_FILE_ERROR,
                G_KEY_FILE_ERROR_KEY_NOT_FOUND);
+  g_assert_null (value);
   g_key_file_free (keyfile);
 
   keyfile = g_key_file_new ();
@@ -1177,6 +1179,7 @@ test_key_names (void)
   check_error (&error,
                G_KEY_FILE_ERROR,
                G_KEY_FILE_ERROR_KEY_NOT_FOUND);
+  g_assert_null (value);
   g_key_file_free (keyfile);
 
   keyfile = g_key_file_new ();
diff --git a/glib/tests/mainloop.c b/glib/tests/mainloop.c
index 1368e9bc053ffce3f0ce9419653c0f01f1631657..ec96bfa8adc70494d11b7a71c50cdc4fc0aace26 100644
--- a/glib/tests/mainloop.c
+++ b/glib/tests/mainloop.c
@@ -121,6 +121,7 @@ test_maincontext_basic (void)
   g_source_set_funcs (source, &funcs);
   g_source_set_callback (source, cb, data, NULL);
   id = g_source_attach (source, ctx);
+  g_assert_cmpint (id, >, 0);
   g_source_unref (source);
   g_assert_true (g_source_remove_by_user_data (data));
   g_assert_false (g_source_remove_by_user_data ((gpointer)0x1234));
diff --git a/glib/tests/mutex.c b/glib/tests/mutex.c
index e4302fd74a1b6106baa74bc2df8b300fe2c04ebf..a5ba2ea95c5e2b96c24e15df8eef8f0a8e8d7952 100644
--- a/glib/tests/mutex.c
+++ b/glib/tests/mutex.c
@@ -186,14 +186,16 @@ addition_thread (gpointer value)
 static void
 test_mutex_perf (gconstpointer data)
 {
-  gint n_threads = GPOINTER_TO_INT (data);
+  guint n_threads = GPOINTER_TO_UINT (data);
   GThread *threads[THREADS];
   gint64 start_time;
   gdouble rate;
   gint x = -1;
-  gint i;
+  guint i;
+
+  g_assert (n_threads <= G_N_ELEMENTS (threads));
 
-  for (i = 0; i < n_threads - 1; i++)
+  for (i = 0; n_threads > 0 && i < n_threads - 1; i++)
     threads[i] = g_thread_create (addition_thread, &x, TRUE, NULL);
 
   /* avoid measuring thread setup/teardown time */
@@ -204,7 +206,7 @@ test_mutex_perf (gconstpointer data)
   rate = g_get_monotonic_time () - start_time;
   rate = x / rate;
 
-  for (i = 0; i < n_threads - 1; i++)
+  for (i = 0; n_threads > 0 && i < n_threads - 1; i++)
     g_thread_join (threads[i]);
 
   g_test_maximized_result (rate, "%f mips", rate);
@@ -223,15 +225,15 @@ main (int argc, char *argv[])
 
   if (g_test_perf ())
     {
-      gint i;
+      guint i;
 
-      g_test_add_data_func ("/thread/mutex/perf/uncontended", NULL, test_mutex_perf);
+      g_test_add_data_func ("/thread/mutex/perf/uncontended", GUINT_TO_POINTER (0), test_mutex_perf);
 
       for (i = 1; i <= 10; i++)
         {
           gchar name[80];
-          sprintf (name, "/thread/mutex/perf/contended/%d", i);
-          g_test_add_data_func (name, GINT_TO_POINTER (i), test_mutex_perf);
+          sprintf (name, "/thread/mutex/perf/contended/%u", i);
+          g_test_add_data_func (name, GUINT_TO_POINTER (i), test_mutex_perf);
         }
     }
 
diff --git a/glib/tests/regex.c b/glib/tests/regex.c
index ee9cd21cac08be8bd7876181288a5b61b625ff48..1ea6f9288a74d00e7deb62c59e4b17108e37b382 100644
--- a/glib/tests/regex.c
+++ b/glib/tests/regex.c
@@ -712,6 +712,7 @@ test_fetch_all (gconstpointer d)
   l_exp = data->expected;
   for (i = 0; l_exp != NULL; i++, l_exp = g_slist_next (l_exp))
     {
+      g_assert_nonnull (matches);
       g_assert_cmpstr (l_exp->data, ==, matches[i]);
     }
 
@@ -800,6 +801,7 @@ test_split_simple (gconstpointer d)
   l_exp = data->expected;
   for (i = 0; l_exp != NULL; i++, l_exp = g_slist_next (l_exp))
     {
+      g_assert_nonnull (tokens);
       g_assert_cmpstr (l_exp->data, ==, tokens[i]);
     }
 
@@ -883,6 +885,7 @@ test_split_full (gconstpointer d)
   l_exp = data->expected;
   for (i = 0; l_exp != NULL; i++, l_exp = g_slist_next (l_exp))
     {
+      g_assert_nonnull (tokens);
       g_assert_cmpstr (l_exp->data, ==, tokens[i]);
     }
 
@@ -915,6 +918,7 @@ test_split (gconstpointer d)
   l_exp = data->expected;
   for (i = 0; l_exp != NULL; i++, l_exp = g_slist_next (l_exp))
     {
+      g_assert_nonnull (tokens);
       g_assert_cmpstr (l_exp->data, ==, tokens[i]);
     }