hg: jdk/sandbox: 8240576: JVM crashes after transformation in C2 IdealLoopTree::merge_many_backedges

[chris.hegarty at oracle.com]

Changeset: 0238badf51bc
Author:    fyang
Date:      2020-03-09 22:31 +0800
URL:       https://hg.openjdk.java.net/jdk/sandbox/rev/0238badf51bc

8240576: JVM crashes after transformation in C2 IdealLoopTree::merge_many_backedges
Reviewed-by: kvn
Contributed-by: hedongbo at huawei.com

! src/hotspot/share/opto/loopnode.cpp
+ test/hotspot/jtreg/compiler/loopopts/TestBeautifyLoops.java