Could the following patch be a step toward a fix? (Also attached)

diff --git a/tccgen.c b/tccgen.c
index 1a8ba3d..68fcd19 100644
--- a/tccgen.c
+++ b/tccgen.c
@@ -5750,11 +5750,13 @@ static void block(int *bsym, int *csym, int is_expr)
         for (b = 1; b < sw.n; b++)
             if (sw.p[b - 1]->v2 >= sw.p[b]->v1)
                 tcc_error("duplicate case value");
+        vpushv(&switchval);
         /* Our switch table sorting is signed, so the compared
            value needs to be as well when it's 64bit.  */
-        if ((switchval.type.t & VT_BTYPE) == VT_LLONG)
-            switchval.type.t &= ~VT_UNSIGNED;
-        vpushv(&switchval);
+        if ((switchval.type.t & VT_BTYPE) == VT_LLONG) {
+            switchval.type.t = VT_LLONG;
+            gen_cast(&switchval.type);
+        }
         gcase(sw.p, sw.n, &a);
         vpop();
         if (sw.def_sym)