[Ping] Re: Request for Approval: Backport of 8146792 : Predicate moved after partial peel may lead to broken graph

[Andrew John Hughes]

On 06/08/2019 01:35, Yangfei (Felix) wrote:
> Ping...
> 
> This has passed jtreg test with a jdk8u fastdebug x86-64 build.  Is it OK to backport this?
> 
> Thanks,
> Felix
> 
> 
> 
> Hi,
> 
> 
> 
> Please approve the backport of 8146792 to 8u-dev.
> 
> 
> 
> This issue can always be reproduced with jdk built from the latest jdk8u master repo:
> 
> 
> 
> Test case reduced from one fuzz test:
> 
> public class Test {
> 
> 
> 
>     public static void foo() {
> 
>         int iArr1[]   = new int[10];
> 
>         int iArr2[][] = new int[10][10];
> 
> 
> 
>         for (long i = 0; i < 8; ++i) {
> 
>             iArr1[(int)i] = 10;
> 
> 
> 
>             for (int j = 0; j < 16; ++j) {
> 
>                 iArr1 = iArr2[0];
> 
>             }
> 
>         }
> 
>     }
> 
> 
> 
>     public static void main(String[] strArr) {
> 
>         for (int i = 0; i < 256; i++) {
> 
>             foo();
> 
>         }
> 
>     }
> 
> 
> 
> }
> 
> 
> 
> Command line: java -XX:+UseSerialGC -XX:-TieredCompilation -XX:-RangeCheckElimination -XX:-BackgroundCompilation -XX:-UseOnStackReplacement -XX:LoopMaxUnroll=1 -XX:-UseCompressedClassPointers -XX:-UseCompressedOops -XX:CompileCommand=compileonly,Test::foo Test
> 
> 
> 
> JVM crashed due to bad C2 graph.  This issue will not trigger with -XX:-UseLoopPredicate.
> 
> 
> 
>       Bug: https://bugs.openjdk.java.net/browse/JDK-8146792
> 
>       JDK9 Changeset: http://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/2748d975045f
> 
> 
> 
>       This backport is almost clean for the latest jdk8u master repo.
> 
> 
> 
> Thanks,
> 
> Felix
> 

I saw your approval flag in the bug database, but there was no mention
of whether the patch applied cleanly or not. I see no webrev link either
there or in this e-mail. Can you clarify what you mean by "almost clean"
or maybe just provide a webrev for review?

Thanks,
-- 
Andrew :)

Senior Free Java Software Engineer
Red Hat, Inc. (http://www.redhat.com)

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