RFR: 8347006: LoadRangeNode floats above array guard in arraycopy intrinsic

[Aleksey Shipilev]

On Wed, 8 Jan 2025 12:23:50 GMT, Tobias Hartmann <thartmann at openjdk.org> wrote:

>> test/hotspot/jtreg/compiler/arraycopy/TestArrayCopyNoInit.java line 32:
>> 
>>> 30:  *                   compiler.arraycopy.TestArrayCopyNoInit
>>> 31:  * @run main/othervm -XX:-BackgroundCompilation -XX:-UseOnStackReplacement -XX:TypeProfileLevel=020
>>> 32:  *                   -XX:+UnlockExperimentalVMOptions -XX:+UseCompactObjectHeaders -XX:-UseTLAB
>> 
>> You have been able to reproduce this with `-UseCompressedClassPointers`, right? If so, I'd suggest we do a run config with `-UseCCP` instead of `+UseCOH`, because this gives us a cleaner way for backports, if we need one later.
>
>> You have been able to reproduce this with -UseCompressedClassPointers, right?
> 
> No, I was never able to reproduce this with `-XX:-UseCompressedClassPointers`.

OK, I was confused by this in PR body then:

> I was able to reliably reproduce the issue with compiler/arraycopy/TestArrayCopyNoInit.java and -XX:-UseTLAB -XX:+UnlockExperimentalVMOptions -XX:-UseCompressedClassPointers on Linux AArch64 and verified that the fix solves the problem.

But fine, if it reproduces with +UCOH, let it be there.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/22967#discussion_r1907107122