RFR: 8366984: Remove delay slot support

Tue Sep 9 09:26:04 UTC 2025

On Tue, 9 Sep 2025 09:04:48 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> SPARC was the only supported architecture that uses a delay slot. The SPARC port was removed in JDK 15, and the code is effectively dead. Let's remove it.
>> 
>> The changes are no-op on all architectures that do not use delay slots. I still tested tier 1-5 on mach5, no related failures.
>
> src/hotspot/cpu/arm/arm.ad line 3383:
> 
>> 3381:     BR     : R;
>> 3382: %}
>> 3383: 
> 
> Where was this used? Or is it an unrelated cleanup?

Removing the comment alone didn't feel quite right, so I removed the following block as well. The block appears to be unused. It was copy-pasted from [SPARC](https://github.com/openjdk/jdk/blob/8153779ad32d1e8ddd37ced826c76c7aafc61894/hotspot/src/cpu/sparc/vm/sparc.ad#L4984), where it was also unused.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27119#discussion_r2332702728