RFR: 8320622: [TEST] Improve coverage of compiler/loopopts/superword/TestMulAddS2I.java on different platforms

[Fei Gao]

On Mon, 20 May 2024 18:49:25 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

> Are all platforms support both (`true` and `false`) values of `AlignVector`? I see it is only adjusted for x86 and aarch64 in `vm_version_<cpu>.cpp` files.

Thanks for your review @vnkozlov . Yeah, and `AlignVector` only works by the return value here, https://github.com/openjdk/jdk/blob/d6b7f9b170b6ce4f7275cc7595b71b9a3e93c133/src/hotspot/share/opto/superword.hpp#L575. `Matcher::misaligned_vectors_ok()` is architecture dependent. `AlignVector` is `true` by default. When we sets `false` by cmd line, if the platform doesn't support misaligned load/store, `Matcher::misaligned_vectors_ok()` should return `false` and the actual value of `vectors_should_be_aligned()` is still `true` . It should be okay to set `true` or `false` on all platforms. WDYT?

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PR Comment: https://git.openjdk.org/jdk/pull/19305#issuecomment-2122264610