[llvm] [RFC][CodeGen] Add generic target feature checks for intrinsics (PR #201470)

[Shilei Tian via llvm-commits]

shiltian wrote:

> > This would require a mutable cache, which is not ideal.
> 
> This is what mutable is for

Do you mean the `mutable` keyword or this cache? The former is because `TargetSubtargetInfo` is mostly used with `const`, and the latter is for performance consideration.

https://github.com/llvm/llvm-project/pull/201470