RFR: 8300590: [JVMCI] BytecodeFrame.equals is broken [v2]

[Doug Simon]

On Fri, 20 Jan 2023 03:59:05 GMT, Dean Long <dlong at openjdk.org> wrote:

>> Doug Simon has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   fix compilation error and formatting
>
> src/jdk.internal.vm.ci/share/classes/jdk.vm.ci.code/src/jdk/vm/ci/code/BytecodeFrame.java line 374:
> 
>> 372:         }
>> 373:         if (getClass() != obj.getClass()) {
>> 374:             return false;
> 
> Is this comparison better/faster than instanceof, and allows the compiler to avoid repeating the same check on the checkcast below?

It's what Eclipse auto-generates for `equals`. I can confirm that Graal eliminates the check cast but don't think it's worth worrying about if not all compilers will.

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PR: https://git.openjdk.org/jdk/pull/12084