target_clones: molehill or everest?

[kinke]

On Tuesday, 7 June 2022 at 14:18:11 UTC, Bruce Carneal wrote:
> Would adding clang's *target_clones* attribute be difficult?

Hmm, it's apparently not supported in LLVM IR directly; the IR 
changes for clang are substantial: 
https://cpp.godbolt.org/z/WT56axqj1

So unless the LLVM API provides a helper (mainly generating the 
resolver with its conditions depending on some 
`__cpu_indicator_init()` and `__cpu_model`), it's probably 
difficult indeed.