RFR: 8320725: C2: Add "requires_strict_order" flag for floating-point add-reduction [v10]

[Emanuel Peter]

On Fri, 24 May 2024 08:36:51 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> Bhavana Kilambi has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Modify JTREG IR rules and some style/format changes
>
> test/hotspot/jtreg/compiler/c2/irTests/TestVectorFPReduction.java line 24:
> 
>> 22:  */
>> 23: 
>> 24: package compiler.c2.irTests;
> 
> Would you mind moving the tests away from `c2/irTests`, and into the `loopopts/superword` and `vectorapi` directories, please?  `c2/irTests` is kind of a disorganized "catch-all". We only had this directory at the beginning of the IR-framework before it was widely adapted. Now it makes more sense to sort the tests by "what" they test, rather than "how" ;)

Ah, I see one is already in the `vectorapi` directory, great!

> test/hotspot/jtreg/compiler/c2/irTests/TestVectorFPReduction.java line 32:
> 
>> 30:  * @bug 8320725
>> 31:  * @summary Ensure strictly ordered AddReductionVF/VD nodes are generated on SVE machines
>> 32:  * while being disabled on Neon
> 
> Suggestion:
> 
>  *          while being disabled on Neon

nit: we usually indent the second line with the start of the summary-text of the first line.

> test/hotspot/jtreg/compiler/vectorapi/TestVectorAddMulReduction.java line 42:
> 
>> 40:  * @bug 8320725
>> 41:  * @library /test/lib /
>> 42:  * @requires os.arch == "aarch64"
> 
> I think there is no reason to only run the test on aarch64. We can run the test anywhere, but the applyIf specifies on what platforms the IR rules are executed.

So you can use the `asimd` or `avx...` features for that.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18034#discussion_r1613112462
PR Review Comment: https://git.openjdk.org/jdk/pull/18034#discussion_r1613085012
PR Review Comment: https://git.openjdk.org/jdk/pull/18034#discussion_r1613106185