[jdk21u-dev] RFR: 8332920: C2: Partial Peeling is wrongly applied for CmpU with negative limit

[Christian Hagedorn]

On Thu, 20 Jun 2024 13:18:02 GMT, Martin Doerr <mdoerr at openjdk.org> wrote:

> @chhagedorn: I'm getting timeouts when trying the new test in JDK 21u:
> 
> ```
> compiler/loopopts/TestPartialPeelAtUnsignedTestsNegativeLimit.java#Xbatch              Error. Program `/jdk21_opt/images/jdk/bin/java' timed out (timeout set to 480000ms, elapsed time including timeout handling was 480262ms).
> compiler/loopopts/TestPartialPeelAtUnsignedTestsNegativeLimit.java#Xcomp-compile-test  Error. Program `/jdk21_opt/images/jdk/bin/java' timed out (timeout set to 480000ms, elapsed time including timeout handling was 480283ms).
> compiler/loopopts/TestPartialPeelAtUnsignedTestsNegativeLimit.java#Xcomp-run-inline    Error. Program `/jdk21_opt/images/jdk/bin/java' timed out (timeout set to 480000ms, elapsed time including timeout handling was 480267ms).
> compiler/loopopts/TestPartialPeelAtUnsignedTestsNegativeLimit.java#vanilla             Passed. Execution successful
> ```
> 
> Do you know if there's a bug or a performance problem? The related issues are already integrated.

The tests use the new `CompileOnly` format which only went into JDK 22 with [JDK-8027711](https://bugs.openjdk.org/browse/JDK-8027711). It looks like with JDK 21u, the `CompileOnly` command is just ignored and none of these test methods get compiled and the tests become really slow when only executing them with the interpreter (we have some iteration-heavy loops in these tests).

I suggest to simply change `CompileOnly` to separate `CompileCommand=compileonly` statements.

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PR Comment: https://git.openjdk.org/jdk21u-dev/pull/728#issuecomment-2180755690