RFR: 8320725: C2: Add "requires_strict_order" flag for floating-point add-reduction [v8]

[Bhavana Kilambi]

On Mon, 13 May 2024 11:01:30 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> @eme64 Thanks for the clarification. I understand the usage of `counts` in the IR tests. Just that I got a bit confused by some of your earlier statements. We do actually have a test to make sure AddReductionVF/VD and MulReductionVF/VD are not generated on aarch64 NEON machines - `test/hotspot/jtreg/compiler/c2/irTests/TestDisableAutoVectOpcodes.java`. I can modify this test to include UseSVE > 0 case as well and will also add a separate JTREG test for the VectorAPI tests. Hope that's ok..
>
> @Bhavana-Kilambi
> I know we have the tests in `test/hotspot/jtreg/compiler/c2/irTests/TestDisableAutoVectOpcodes.java`, and some other reduction tests. But these do not do the specific think I would like to see.
> 
> I would like this:
> - Add `no_strict_order` vs `requires_strict_order` or similar to `dump_spec`.
> - IR match not just that there is the correct `ReductionNode`, but also that it has the `no_strict_order` or `requires_strict_order` in its dump. You can do that by using a custom regex string, rather than `IRNode.STORE_VECTOR` or similar.
> - Then, create different tests, some where we expect ordered, some unordered vectors. Use Vector API and SuperWord examples.
> 
> Does that make sense?

Hi @eme64 , I have modified the tests as suggested. Please review :)

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PR Comment: https://git.openjdk.org/jdk/pull/18034#issuecomment-2144609426