[clang] [Clang][AArch64] Add pessimistic vscale_range when sve is in target-f… (PR #137624)

[Eli Friedman via cfe-commits]

efriedma-quic wrote:

Those tests are already generating that warning; I assume the "new" warning is a duplicate?  That seems like a bug in the x86 handling for target features: it should generate a warning at most once per function, and the warning should point to the function in question.  (Currently, it generates three warnings per function with no source location.  CC @phoebewang @e-kud @KanRobert .)

It might make sense to refactor the way getFunctionFeatureMap works; maybe add some kind of cache so we aren't constantly recomputing it.

https://github.com/llvm/llvm-project/pull/137624