Properly detect and enable vectorization on ARM

!320 (merged) has the side effect of breaking detection of SVE vectorization support and enablement of SVE in the compiler. My patch should properly fix the underlying problem.

py-cpuinfo is supported on ARM64 and can be used to detect Neon and SVE. However, there was indeed a bug here -- Neon is identified as asimd in /proc/cpuinfo, so we should check for asimd instead of neon.

While -march=native was not supported by Clang before 15, -mcpu=native is supported by GCC 6+ and Clang 7+. Let's use that instead of not adding a flag at all -- otherwise SVE support is not enabled in the compiler even if the hardware supports it.

requested review from @schottenhamml

assigned to @schottenhamml

@schottenhamml can you please take a quick look at these changes

@schottenhamml, have you had a chance to try out whether this fixes the problem you originally tried to solve with !320 (merged)?

added 12 commits

• d01fc61c...e356d3d7 - 10 commits from branch master
• 70afe477 - Merge remote-tracking branch 'origin/master' into arm64
• 8d99d156 - Remove cpuinfo dependency for SIMD detection on non-x86

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added 1 commit

• 6cb620bb - Remove cpuinfo dependency for SIMD detection on non-x86

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@schottenhamml, as per our discussion, I removed the py-cpuinfo dependency on non-x86 architecture. Detection now takes place natively via ELF_HWCAP on Linux on ppc64, ppc64le, armv8, armv9. The same mechanism was already used on riscv. This codepath is now actually tested in CI, except on riscv, where QEMU does not support it yet.

mentioned in merge request !328 (merged)

added 1 commit

• f0e9cd00 - Remove cpuinfo dependency for SIMD detection on non-x86

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added 4 commits

• f0e9cd00...fd1c1259 - 3 commits from branch master
• cede566a - Merge remote-tracking branch 'origin/master' into arm64

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added 4 commits

• cede566a...30b55d00 - 3 commits from branch master
• 267ce6a4 - Merge remote-tracking branch 'origin/master' into arm64

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requested review from @holzer and removed review request for @schottenhamml

requested review from @schottenhamml and removed review request for @holzer

resolved all threads

merged

mentioned in commit 178b4df7