RFR: 8366815: C2: Delay Mod/Div by constant transformation [v2]

[Hannes Greule]

On Mon, 27 Oct 2025 18:40:09 GMT, Vladimir Ivanov <vlivanov at openjdk.org> wrote:

>> Hannes Greule has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   expand comments
>
> src/hotspot/share/opto/divnode.cpp line 556:
> 
>> 554:   // Less precise comparisons still work after transform_int_divide, e.g.,
>> 555:   // comparing with >= 21_476 does not conflict with the off-by-one overapproximation.
>> 556:   if (phase->is_IterGVN() == nullptr) {
> 
> `can_reshape == true` is equivalent and IMO a bit clearer than a subtype check.

I'll change it. I didn't use it before due to e.g., https://bugs.openjdk.org/browse/JDK-8255443.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27886#discussion_r2468109400