hg: jdk/submit: 8202948: C2: assert(init_offset >= 0) failed: positive offset from object start

[vladimir.kozlov at oracle.com]

Changeset: 1ab701eb7de4
Author:    kvn
Date:      2018-06-15 08:28 -0700
URL:       http://hg.openjdk.java.net/jdk/submit/rev/1ab701eb7de4

8202948: C2: assert(init_offset >= 0) failed: positive offset from object start
Summary: convert the assert into compilation check which will skip superword optimization
Reviewed-by: roland, thartmann

! src/hotspot/share/opto/superword.cpp
+ test/hotspot/jtreg/compiler/loopopts/superword/TestNegBaseOffset.java