diff --git a/arm64-gen.c b/arm64-gen.c
index 35538d1..a73018e 100644
--- a/arm64-gen.c
+++ b/arm64-gen.c
@@ -242,17 +242,22 @@ ST_FUNC void gsym_addr(int t_, int a_)
 
 static int arm64_type_size(int t)
 {
+    /*
+     * case values are in increasing order (from 1 to 11).
+     * which 'may' help compiler optimizers. See tcc.h
+     */
     switch (t & VT_BTYPE) {
-    case VT_INT: return 2;
     case VT_BYTE: return 0;
     case VT_SHORT: return 1;
+    case VT_INT: return 2;
+    case VT_LLONG: return 3;
     case VT_PTR: return 3;
     case VT_FUNC: return 3;
+    case VT_STRUCT: return 3;
     case VT_FLOAT: return 2;
     case VT_DOUBLE: return 3;
     case VT_LDOUBLE: return 4;
     case VT_BOOL: return 0;
-    case VT_LLONG: return 3;
     }
     assert(0);
     return 0;
diff --git a/tests/tests2/73_arm64.c b/tests/tests2/73_arm64.c
index 8de61b3..855c476 100644
--- a/tests/tests2/73_arm64.c
+++ b/tests/tests2/73_arm64.c
@@ -230,6 +230,17 @@ void ret(void)
     printf("%.1Lf %.1Lf\n", fr_hfa34().a, fr_hfa34().d);
 }
 
+void*
+va_arg_with_struct_ptr(va_list ap) {
+        /*
+         * This was a BUG identified with FFTW-3.3.8 on arm64.
+         * The test case only checks it compiles.
+         */
+        struct X { int _x; };
+        struct X *x = va_arg(ap, struct X *);
+        return x;
+}
+
 int match(const char **s, const char *f)
 {
     const char *p = *s;