[clang] [llvm] [ARM] Armv8-R does not require fp64 or neon. (PR #88287)

[David Green via cfe-commits]

davemgreen wrote:

Does this disable neon by default for cortex-r52? If so I don't think it should be doing that, it would be a break in the existing behaviour, and should at least be in the release notes.

The general rule for -mcpu options is that they should (roughly) enable the maximum set of features available, and from there can be disabled with -mfpu or +nofp options. Essentially the default is -mfpu=auto. Keeping to this keeps things consistent between cores, so long as people understand the rule. For architectures the default should be without, but as far as I understand we still default to -mfpu=auto.

https://github.com/llvm/llvm-project/pull/88287