RFR: 8353192: C2: Clean up x86 backend after 32-bit x86 removal [v2]

[Emanuel Peter]

On Mon, 7 Apr 2025 08:47:19 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Piece-wise cleanup of C2 x86 backend. C2_MacroAssembler, x86.ad and related files are the target for this cleanup. 
>> 
>> Additional testing:
>>  - [x] Linux x86_64 server fastdebug, `all`
>>  - [x] Linux x86_64 server fastdebug, `all` + `-XX:-TieredCompilation`
>
> Aleksey Shipilev has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains five additional commits since the last revision:
> 
>  - Cleanup ADLC as well
>  - Revert some accidental removals
>  - Merge branch 'master' into JDK-8353192-x86-c2-backend
>  - Touchup
>  - Fix

Looks reasonable :)

I launched some internal testing just in case, please ping me again in 24h :)

src/hotspot/cpu/x86/x86.ad line 1659:

> 1657:         return false;
> 1658:       }
> 1659:       break;

So just `!VM_Version::supports_bmi2()` is not possible any more?

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PR Review: https://git.openjdk.org/jdk/pull/24300#pullrequestreview-2750807491
PR Review Comment: https://git.openjdk.org/jdk/pull/24300#discussion_r2033680072