[clang] [llvm] [llvm][AArch64] SVE2 is an optional feature in ARMv9.0a (PR #96007)

[Sander de Smalen via cfe-commits]

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@@ -955,6 +955,11 @@ Arm and AArch64 Support
     * Arm Neoverse-N3 (neoverse-n3).
     * Arm Neoverse-V3 (neoverse-v3).
     * Arm Neoverse-V3AE (neoverse-v3ae).
+- SVE and SVE2 have been moved to the default extensions list for ARMv9.0,
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sdesmalen-arm wrote:

I don't think this note to Clang is required, because the definition of `v9a` is an LLVM-internal concept.
>From an end-user point of view, invoking Clang with `-march=armv9-a` should still enable SVE2.

https://github.com/llvm/llvm-project/pull/96007