[jdk18] RFR: 8279032: compiler/loopopts/TestSkeletonPredicateNegation.java times out with -XX:TieredStopAtLevel < 4

[Fairoz Matte]

On Mon, 10 Jan 2022 08:00:14 GMT, Fairoz Matte <fmatte at openjdk.org> wrote:

> 8279032: compiler/loopopts/TestSkeletonPredicateNegation.java times out with -XX:TieredStopAtLevel < 4

This was my findings before arriving at the suggestion, 
I just reduced test case to make it bit quick, below are the results
```             TestSkeletonPredicateNegation instance = new TestSkeletonPredicateNegation();
-           for (int i = 0; i < 10000; ++i) {
+            for (int i = 0; i < 1000; ++i) {
                 instance.mainTest(args);
             }

Interpreter -Xint -  1843.357 seconds
C1 with TieredStopAtLevel=3 -  1636.454 seconds
C2 (default) -  1.862 seconds

For me it looks like it is not an issue with the C1 or interpreter.

The test case is designed to execute only on C2 

We may need to fix the testcase with @requires vm.compiler2.enabled

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PR: https://git.openjdk.java.net/jdk18/pull/89