RFR: 8266528: Optimize C2 VerifyIterativeGVN execution time [v2]

[Hui Shi]

On Mon, 17 May 2021 19:37:28 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> Hui Shi has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   update test requires from "vm.flavor == "server"" to vm.compiler2.enabled
>
> src/hotspot/share/opto/node.cpp line 2249:
> 
>> 2247:         }
>> 2248:       }
>> 2249:       if (cnt == 2) {
> 
> I think it should be `cnt > 1`.

previous loop breaks when meet first input which is same with x, so cnt must be 2 if x is duplicated with previous input.

> test/hotspot/jtreg/compiler/debug/TraceIterativeGVN.java line 27:
> 
>> 25: /*
>> 26:  * @test
>> 27:  * @requires vm.debug == true & vm.flavor == "server"
> 
> Use `vm.compiler2.enabled` instead of `vm.flavor == "server"`

Got! updated in new commit.

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PR: https://git.openjdk.java.net/jdk/pull/4045