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

[Matt Arsenault via cfe-commits]

arsenm wrote:

> Unfortunately, I don't have an upstream AMDGPU use case for this right now, but we definitely have one downstream.
> 
> The basic scenario is that an intrinsic requires feature X or feature Y, where X is available on one set of targets, T1, while Y is not supported on T1 but is supported on another set of targets, T2. Technically, if we don't want to support OR syntax, we could introduce a new target feature and enable it on both T1 and T2.

We're definitely underutilizing the Implies field of subtarget features (but I'm not sure which case you mean)




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