[jdk17] RFR: 8268405: Several regressions 4-17% after CHA changes [v2]

[Dean Long]

On Tue, 15 Jun 2021 22:38:03 GMT, Vladimir Ivanov <vlivanov at openjdk.org> wrote:

>> Recevier validation code in `Compile::optimize_inlining()` added by JDK-8267807 is way too strict. In particular, it rejects perfectly valid cases when unique concrete method comes from a superclass ( `receiver_type->klass() <: 
>>  cha_monomorphic_target->holder()`).  
>> 
>> Instead of reworking the validation logic, I decided to completely get rid of it and follow John's @rose00 suggestion [1] to perform receiver checks at runtime when needed. As I described earlier [2], receiver checks should never fail unless there's a product bug lurking in the code. Debug builds will assert if it ever happens (controlled by `-XX:+-VerifyReceiverTypes`), but product builds will deoptimize at the call site instead.
>> 
>> (The fix depends on #55 to avoid assertion failures in `Parse::do_field_access()`.)
>> 
>> Testing:
>> - [x] hs-tier1 - hs-tier6
>> - [x] manual performance runs (dacapo-jython, in particular)  
>> 
>> [1] https://github.com/openjdk/jdk/pull/4212#discussion_r643467030
>> [2] https://github.com/openjdk/jdk/pull/4212#discussion_r644377036
>
> Vladimir Ivanov has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Comments

Marked as reviewed by dlong (Reviewer).

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PR: https://git.openjdk.java.net/jdk17/pull/60