RFR 8232008: Shenandoah: C1 load barrier does not match interpreter version

[Roman Kennke]

Looks good. Thanks!

Roman


> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8232008
> Webrev: http://cr.openjdk.java.net/~zgu/JDK-8232008/webrev.00/
> 
> Test:
>   hotspot_gc_shenandoah (fastdebug and release) with x86_64 and x86-32
> JVM on Linux.
> 
> Thanks,
> 
> -Zhengyu
>