[lworld] RFR: 8235914: [lworld] Profile acmp bytecode [v6]

[Tobias Hartmann]

On Mon, 12 Oct 2020 13:30:04 GMT, Roland Westrelin <roland at openjdk.org> wrote:

>> This includes:
>> - a new ProfileData structure to profile both inputs to acmp
>> - profile collection at acmp in the interpreter on x86
>> - profile collection at acmp in c1 generated code on x86
>> - changes to c2's acmp implementation to leverage profiling (both existing profiling through type speculation and new
>>   profile data at acmp)
>> - small tweaks to the assembly code generated for acmp
>> - a change to the implementation of LIRGenerator::profile_null_free_array() so it doesn't use a branch (which is
>>   dangerous given the register allocator is not aware of branches added at the LIR level)
>> - new tests
>> 
>> Profile collection happens unconditionally. Leveraging profiling at acmp is under UseACmpProfile which is false by
>> default.
>
> Roland Westrelin has updated the pull request incrementally with one additional commit since the last revision:
> 
>   more review

Thanks for making these changes. Looks good to me.

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Marked as reviewed by thartmann (Committer).

PR: https://git.openjdk.java.net/valhalla/pull/185