RFR: 8286451: C2: assert(nb == 1) failed: only when the head is not shared [v2]

Tue Jun 7 15:08:47 UTC 2022

On Tue, 7 Jun 2022 12:40:17 GMT, Christian Hagedorn <chagedorn at openjdk.org> wrote:

> Looks good!

Thanks for the review.

> > nb counts the number of loops that share a single head
> 
> Maybe you also want to rename the variable to make it more clear what it counts.

Done.

> test/hotspot/jtreg/compiler/ciTypeFlow/TestSharedLoopHead.java line 28:
> 
>> 26:  * @bug 8286451
>> 27:  * @summary C2: assert(nb == 1) failed: only when the head is not shared
>> 28:  * @run main/othervm TestSharedLoopHead
> 
> Could be converted to `@run driver TestSharedLoopHead` instead.

Right but the test needs -XX:-BackgroundCompilation

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PR: https://git.openjdk.java.net/jdk/pull/8947