RFR (S) [8u] 8155635: C2: Mixed unsafe oop accesses break alias analysis

[Vladimir Kozlov]

Specifying GC in test is 'no-no'. You can have conflict when testing environment pass different GC flag. And I did not 
find in Bug or Review that it is G1 specific problem.

Otherwise looks good.

Thanks,
Vladimir

On 10/19/18 1:15 AM, David Buck wrote:
> Hi!
> 
> May I please get a review of this straightforward backport:
> 
> bug report:
> https://bugs.openjdk.java.net/browse/JDK-8155635
> 
> JDK 9 code review thread:
> http://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2016-August/024250.html
> 
> JDK 9 changeset:
> http://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/bde4bcd58309
> 
> JDK 8 webrev (for review):
> http://cr.openjdk.java.net/~dbuck/jdk8155635_jdk8_ver00/
> 
> The only minor differences from the JDK 9 fix are the different assert message formatting [0] and the following changes 
> to the testcase:
> 
> - use of com.oracle.java.testlibrary.Utils to get Unsafe
> - addition of -XX:+UseG1GC to command line (this is default in JDK 9, so explicit flag was not needed)
> 
> Cheers,
> -Buck
> 
> [0] https://bugs.openjdk.java.net/browse/JDK-8080775