hg: jdk/sandbox: 8219807: C2 crash in IfNode::up_one_dom(Node*, bool)

[chris.hegarty at oracle.com]

Changeset: 332f28c3a105
Author:    thartmann
Date:      2019-04-30 14:49 +0200
URL:       http://hg.openjdk.java.net/jdk/sandbox/rev/332f28c3a105

8219807: C2 crash in IfNode::up_one_dom(Node*, bool)
Summary: Guard against regions degraded to copies.
Reviewed-by: kvn

! src/hotspot/share/opto/ifnode.cpp
+ test/hotspot/jtreg/compiler/c2/TestIfWithDeadRegion.java