hg: jdk/submit: 8224957: C2 compilation fails with assert: Bad graph detected in build_loop_late

[tobias.hartmann at oracle.com]

Changeset: 8e51da27b53a
Author:    thartmann
Date:      2019-08-13 09:56 +0200
URL:       https://hg.openjdk.java.net/jdk/submit/rev/8e51da27b53a

8224957: C2 compilation fails with assert: Bad graph detected in build_loop_late
Summary: Disable walking up the dominator chain for regions with more than 2 input paths.
Reviewed-by: roland, kvn

! src/hotspot/share/opto/c2_globals.hpp
! src/hotspot/share/opto/memnode.cpp
! src/hotspot/share/opto/node.cpp
+ test/hotspot/jtreg/compiler/eliminateAutobox/TestSplitThroughPhi.java