diff --git a/tcg/tcg.c b/tcg/tcg.c
index bdd7a672b..30f3aefe6 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -794,7 +794,9 @@ static char *tcg_get_arg_str_idx(TCGContext *s, char *buf, int buf_size,
 {
     TCGTemp *ts;
 
+    assert(idx >= 0 && idx < s->nb_temps);
     ts = &s->temps[idx];
+    assert(ts);
     if (idx < s->nb_globals) {
         pstrcpy(buf, buf_size, ts->name);
     } else {