2469       // If succ is loop head, find outer loop.
2470       while (lp != NULL && lp->head() == succ) {
2471         lp = lp->parent();
2472       }
2473       if (lp == NULL) {
2474         // Infinite loop, it's parent is the root
2475         lp = loop_tree_root();
2476       }
2477     }
2478 
2479     // Check for irreducible loop.
2480     // Successor has already been visited. If the successor's loop head
2481     // has already been post-visited, then this is another entry into the loop.
2482     while (lp->head()->is_post_visited() && lp != loop_tree_root()) {
2483       _has_irreducible_entry = true;
2484       lp->set_irreducible(succ);
2485       if (!succ->is_on_work_list()) {
2486         // Assume irreducible entries need more data flow
2487         add_to_work_list(succ);
2488       }
2489       lp = lp->parent();
2490       assert(lp != NULL, "nested loop must have parent by now");



2491     }


2492 
2493     // Merge loop tree branch for all successors.
2494     innermost = innermost == NULL ? lp : innermost->sorted_merge(lp);
2495 
2496   } // end loop
2497 
2498   if (innermost == NULL) {
2499     assert(blk->successors()->length() == 0, "CFG exit");
2500     blk->set_loop(loop_tree_root());
2501   } else if (innermost->head() == blk) {
2502     // If loop header, complete the tree pointers
2503     if (blk->loop() != innermost) {
2504 #if ASSERT
2505       assert(blk->loop()->head() == innermost->head(), "same head");
2506       Loop* dl;
2507       for (dl = innermost; dl != NULL && dl != blk->loop(); dl = dl->parent());
2508       assert(dl == blk->loop(), "blk->loop() already in innermost list");
2509 #endif
2510       blk->set_loop(innermost);
2511     }

2469       // If succ is loop head, find outer loop.
2470       while (lp != NULL && lp->head() == succ) {
2471         lp = lp->parent();
2472       }
2473       if (lp == NULL) {
2474         // Infinite loop, it's parent is the root
2475         lp = loop_tree_root();
2476       }
2477     }
2478 
2479     // Check for irreducible loop.
2480     // Successor has already been visited. If the successor's loop head
2481     // has already been post-visited, then this is another entry into the loop.
2482     while (lp->head()->is_post_visited() && lp != loop_tree_root()) {
2483       _has_irreducible_entry = true;
2484       lp->set_irreducible(succ);
2485       if (!succ->is_on_work_list()) {
2486         // Assume irreducible entries need more data flow
2487         add_to_work_list(succ);
2488       }
2489       Loop* plp = lp->parent();
2490       if (plp == NULL) {
2491         // This only happens for some irreducible cases.  The parent
2492         // will be updated during a later pass.
2493         break;
2494       }
2495       lp = plp;
2496     }
2497 
2498     // Merge loop tree branch for all successors.
2499     innermost = innermost == NULL ? lp : innermost->sorted_merge(lp);
2500 
2501   } // end loop
2502 
2503   if (innermost == NULL) {
2504     assert(blk->successors()->length() == 0, "CFG exit");
2505     blk->set_loop(loop_tree_root());
2506   } else if (innermost->head() == blk) {
2507     // If loop header, complete the tree pointers
2508     if (blk->loop() != innermost) {
2509 #if ASSERT
2510       assert(blk->loop()->head() == innermost->head(), "same head");
2511       Loop* dl;
2512       for (dl = innermost; dl != NULL && dl != blk->loop(); dl = dl->parent());
2513       assert(dl == blk->loop(), "blk->loop() already in innermost list");
2514 #endif
2515       blk->set_loop(innermost);
2516     }