RFR: 8328528: C2 should optimize long-typed parallel iv in an int counted loop [v21]

[Tobias Hartmann]

On Thu, 3 Oct 2024 16:31:15 GMT, Kangcheng Xu <kxu at openjdk.org> wrote:

>> Currently, parallel iv optimization only happens in an int counted loop with int-typed parallel iv's. This PR adds support for long-typed iv to be optimized. 
>> 
>> Additionally, this ticket contributes to the resolution of [JDK-8275913](https://bugs.openjdk.org/browse/JDK-8275913). Meanwhile, I'm working on adding support for parallel IV replacement for long counted loops which will depend on this PR.
>
> Kangcheng Xu has updated the pull request incrementally with one additional commit since the last revision:
> 
>   correctly verify outputs with custom @Run methods

`compiler/loopopts/parallel_iv/TestParallelIvInIntCountedLoop.java` times out in our testing both with `-XX:StressLongCountedLoop=200000000` and with `-XX:+UnlockExperimentalVMOptions -XX:PerMethodSpecTrapLimit=0 -XX:PerMethodTrapLimit=0`:


"main" #1 [2771172] prio=5 os_prio=0 cpu=500187.70ms elapsed=503.08s allocated=6554K defined_classes=227 tid=0x0000ffff9002d550 nid=2771172 runnable  [0x0000ffff972bf000]
   java.lang.Thread.State: RUNNABLE
Thread: 0x0000ffff9002d550  [0x2a48e4] State: _at_safepoint _at_poll_safepoint 1
   JavaThread state: _thread_blocked
	at compiler.loopopts.parallel_iv.TestParallelIvInIntCountedLoop.testIntCountedLoopWithIntIVLeq(TestParallelIvInIntCountedLoop.java:93)
	at compiler.loopopts.parallel_iv.TestParallelIvInIntCountedLoop.runTestIntCountedLoopWithIntIVLeq(TestParallelIvInIntCountedLoop.java:103)
	at java.lang.invoke.DirectMethodHandle$Holder.invokeStatic(java.base at 24-internal/DirectMethodHandle$Holder)
	at java.lang.invoke.LambdaForm$MH/0x0000ffff58460870.invoke(java.base at 24-internal/LambdaForm$MH)
	at java.lang.invoke.Invokers$Holder.invokeExact_MT(java.base at 24-internal/Invokers$Holder)
	at jdk.internal.reflect.DirectMethodHandleAccessor.invokeImpl(java.base at 24-internal/DirectMethodHandleAccessor.java:154)
	at jdk.internal.reflect.DirectMethodHandleAccessor.invoke(java.base at 24-internal/DirectMethodHandleAccessor.java:104)
	at java.lang.reflect.Method.invoke(java.base at 24-internal/Method.java:573)
	at compiler.lib.ir_framework.test.CustomRunTest.invokeTest(CustomRunTest.java:159)
	at compiler.lib.ir_framework.test.AbstractTest.run(AbstractTest.java:98)
	at compiler.lib.ir_framework.test.CustomRunTest.run(CustomRunTest.java:89)
	at compiler.lib.ir_framework.test.TestVM.runTests(TestVM.java:861)
	at compiler.lib.ir_framework.test.TestVM.start(TestVM.java:252)
	at compiler.lib.ir_framework.test.TestVM.main(TestVM.java:165)

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PR Comment: https://git.openjdk.org/jdk/pull/18489#issuecomment-2396187667