[clang] [llvm] [AArch64] Add optional extensions enabled on Grace (PR #127620)

[David Green via cfe-commits]

https://github.com/davemgreen commented:

Thanks - this looks sensible to me if these are always present on Grace (I'm not sure how to check that, I will leave for someone else to review). It currently uses a bit of a mixture of specifying features individually (FeatureAES and FeatureSVEAES) and relying on the dependencies (FeatureSVE2SHA3 will imply FeatureSHA3 but isn't specified directly). It might be good to use one or the other, whichever that is, but It shouldn't alter the result.

https://github.com/llvm/llvm-project/pull/127620