On Mon, 2 Nov 2026 17:55:21 GMT, Stuart Monteith <[email protected]> wrote:
>> @stooart-mon Thanks for clarifying. Given that Linux and Windows on AArch64 >> both assume AAPCS64 I think we can assume the ASIMD feature is present. In >> the RFE mentioned above I recommended adding an assert that the feature is >> present (extra braces to augment the security offered by that belt). > > @adinn agreed, we must assume ASIMD is present. It looks likely that Hotspot > would crash before getting to detecting NEON, I see "movi v4.s, #0" > executing before VM_Version::Initialize is executed, so I don't have a strong > opinion on adding an assert. You could even detect whether "__ARM_NEON" had > been defined at compile time and #error if it isn't present, but that would > be probably going too far. I thought that there were Cortex systems that could be configured without Advanced SIMD instructions, but as @stooart-mon had stated, SIMD instructions are required for standard operating systems running advanced applications (OpenJDK) and that these Cortex systems would not be able to support the latter, I suppose. I support dropping this PR, but would at least like to have an assert gating these instructions. ------------- PR Comment: https://git.openjdk.org/jdk/pull/33661#issuecomment-6591508884
