diff --git a/target/i386/ops_sse.h b/target/i386/ops_sse.h
index 3cbc36a59d..0bd6bfad8a 100644
--- a/target/i386/ops_sse.h
+++ b/target/i386/ops_sse.h
@@ -2470,6 +2470,8 @@ void helper_vpermdq_ymm(Reg *d, Reg *v, Reg *s, uint32_t order)
         r0 = s->Q(2);
         r1 = s->Q(3);
         break;
+    default: /* default case added to help the compiler to avoid warnings */
+        g_assert_not_reached();
     }
     switch ((order >> 4) & 3) {
     case 0:
@@ -2488,6 +2490,8 @@ void helper_vpermdq_ymm(Reg *d, Reg *v, Reg *s, uint32_t order)
         r2 = s->Q(2);
         r3 = s->Q(3);
         break;
+    default: /* default case added to help the compiler to avoid warnings */
+        g_assert_not_reached();
     }
     d->Q(0) = r0;
     d->Q(1) = r1;