RFR: 8263352: assert(use == polladr) failed: the use should be a safepoint polling

[Vladimir Kozlov]

On Tue, 23 Mar 2021 19:19:13 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> The main reason of this failure has been shown in JDK-8263352.
>> * JDK-8260637 makes a CastPP unpinned, so it can be pull out of inner loop
>> * JDK-8247307 assert use == polladr and makes it crash here.
>> * I think we can only `intrinsify_fill` the array when it is *really* safe here, so I fix this bug by `return` other cases.
>> In this patch, I will give a small test case called `Test8263352.java` to reproduct this failure.
>> Thanks to @vnkozlov , who found this failure for the first time (to me).
>> Thanks to  @nsjian，who found the case which can reproduct this failure everytime.
>> Thanks to @pfustc, who changed notes with us.
>
> Okay. Lets push the fix as suggested in match_fill_loop() and new test.
> And I will file separate RFE for Roland's changes.

I filed https://bugs.openjdk.java.net/browse/JDK-8264063

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PR: https://git.openjdk.java.net/jdk/pull/3061