1.1 --- a/src/share/vm/opto/loopnode.cpp Mon May 25 07:03:06 2020 +0100
1.2 +++ b/src/share/vm/opto/loopnode.cpp Mon May 25 14:24:27 2020 +0800
1.3 @@ -1,5 +1,5 @@
1.4 /*
1.5 - * Copyright (c) 1998, 2017, Oracle and/or its affiliates. All rights reserved.
1.6 + * Copyright (c) 1998, 2020, Oracle and/or its affiliates. All rights reserved.
1.7 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.8 *
1.9 * This code is free software; you can redistribute it and/or modify it
1.10 @@ -1538,10 +1538,18 @@
1.11 // If I am a shared header (multiple backedges), peel off the many
1.12 // backedges into a private merge point and use the merge point as
1.13 // the one true backedge.
1.14 - if (_head->req() > 3 && !_irreducible) {
1.15 + if (_head->req() > 3) {
1.16 // Merge the many backedges into a single backedge but leave
1.17 // the hottest backedge as separate edge for the following peel.
1.18 - merge_many_backedges( phase );
1.19 + if (!_irreducible) {
1.20 + merge_many_backedges( phase );
1.21 + }
1.22 +
1.23 + // When recursively beautify my children, split_fall_in can change
1.24 + // loop tree structure when I am an irreducible loop. Then the head
1.25 + // of my children has a req() not bigger than 3. Here we need to set
1.26 + // result to true to catch that case in order to tell the caller to
1.27 + // rebuild loop tree. See issue JDK-8244407 for details.
1.28 result = true;
1.29 }
1.30
