- if (mb != n) {
- /* must be a partBlock */
- ASSERT_AND_RET(mb != NULL && (is_Block(mb) || is_Bad(mb)), "wrong MacroBlock header", 0);
+ ASSERT_AND_RET(is_Block(mb) || is_Bad(mb), "Block node with wrong MacroBlock", 0);
+
+ if (is_Block(mb) && mb != n) {
+ /* Blocks with more than one predecessor must be header blocks */