RFR: 8361892: AArch64: Incorrect matching rule leading to improper oop instruction encoding

[Yadong Wang]

On Fri, 11 Jul 2025 05:00:25 GMT, Hao Sun <haosun at openjdk.org> wrote:

> Hi. Not a code review. Our internal CI reported a jtreg failure `test/hotspot/jtreg/sources/TestNoNULL.java` with this PR on Nvidia Grace machine.
> 
> * How to reproduce the failure: build one fastdebug JDK and run `make test TEST="test/hotspot/jtreg/sources/TestNoNULL.java"`
> * The snippet of the error log
> 
> ```
> STDERR:
> Error: 'NULL' found in /tmp/src/hotspot/cpu/aarch64/aarch64.ad at line 4563:
>             n->get_ptr_type()->isa_rawptr() != NULL &&
> java.lang.RuntimeException: Test found 1 usages of 'NULL' in source files. See errors above.
>         at TestNoNULL.main(TestNoNULL.java:84)
>         at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
>         at java.base/java.lang.reflect.Method.invoke(Method.java:565)
>         at com.sun.javatest.regtest.agent.MainActionHelper$AgentVMRunnable.run(MainActionHelper.java:335)
>         at java.base/java.lang.Thread.run(Thread.java:1474)
> 
> JavaTest Message: Test threw exception: java.lang.RuntimeException
> JavaTest Message: shutting down test
> 
> 
> TEST RESULT: Failed. Execution failed: `main' threw exception: java.lang.RuntimeException: Test found 1 usages of 'NULL' in source files. See errors above.
> ```
> 
> It seems that the newly added assertion by this PR is hit in this jtreg case. Could you help take a look at this issue? Thanks.

Sure, I will follow Andrew's suggestion, removing immByteMapBase.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/26249#issuecomment-3060852029