hg: jdk/jdk: 8201367: assert(current != first_mem) failed: corrupted memory graph in superword code

[vladimir.kozlov at oracle.com]

Changeset: a09af8ef8e5c
Author:    roland
Date:      2018-04-26 12:48 -0700
URL:       http://hg.openjdk.java.net/jdk/jdk/rev/a09af8ef8e5c

8201367: assert(current != first_mem) failed: corrupted memory graph in superword code
Summary: don't rely on the RPO order to find the "first" and "last" loads of the pack
Reviewed-by: kvn

! src/hotspot/share/opto/superword.cpp
+ test/hotspot/jtreg/compiler/vectorization/TestUnexpectedLoadOrdering.java