dj.diff

diff --git a/Zend/Optimizer/zend_cfg.c b/Zend/Optimizer/zend_cfg.c
index badf9d298b..a8f6588f2e 100644
--- a/Zend/Optimizer/zend_cfg.c
+++ b/Zend/Optimizer/zend_cfg.c
@@ -887,6 +887,10 @@ ZEND_API int zend_cfg_identify_loops(const zend_op_array *op_array, zend_cfg *cf
 		}
 		while (zend_worklist_len(&work)) {
 			j = zend_worklist_pop(&work);
+			if (j != 0 && blocks[j].idom < 0) {
+				/* Ignore blocks that are unreachable or only abnormally reachable. */
+				continue;
+			}
 			while (blocks[j].loop_header >= 0) {
 				j = blocks[j].loop_header;
 			}