RFR: 8308994: C2: Re-implement experimental post loop vectorization [v4]

[Pengfei Li]

On Tue, 4 Jul 2023 02:40:51 GMT, Pengfei Li <pli at openjdk.org> wrote:

>> test/hotspot/jtreg/compiler/vectorization/runner/ArrayInvariantFillTest.java line 69:
>> 
>>> 67:     @Test
>>> 68:     @IR(applyIfCPUFeatureOr = {"asimd", "true", "sse2", "true"},
>>> 69:         applyIf = {"OptimizeFill", "false"},
>> 
>> This seems unrelated. Why did you have to add this?
>
> Will cleanup this in JDK-8309697.

This is already fixed in another patch. Will close this comment.

>> test/hotspot/jtreg/compiler/vectorization/runner/VectorizationTestRunner.java line 84:
>> 
>>> 82:         TestFramework irTest = new TestFramework(klass);
>>> 83:         // Add extra VM options to enable more auto-vectorization chances
>>> 84:         irTest.addFlags("-XX:-OptimizeFill");
>> 
>> Aha, you removed this too. Fair enough. But since the runner is currently requiring everything to be `flagless`, now I cannot actually force `-XX:-OptimizeFill` from the outside. And that means that potentially the tests are never actually run with `OptimizeFill` off, and we never actually can check the IR rules. We lose test coverage. That makes me a bit nervous.
>> 
>> Suggestion: if tests actually require the flag off to execute the IR rule, then we should have two scenarios, one where the flag is on, and one when it is off.
>
> Again, will cleanup this in JDK-8309697.

It's already cleaned up in another patch. Will close it.

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PR Review Comment: https://git.openjdk.org/jdk/pull/14581#discussion_r1338288996
PR Review Comment: https://git.openjdk.org/jdk/pull/14581#discussion_r1338289635