[libclc] [libclc] Move fmin/fmax to the CLC library (PR #128506)

[Fraser Cormack via cfe-commits]

frasercrmck wrote:

> These should use the regular builtin fmin / fmax.

Do you mean the AMD implementations, or the CLC ones too? Note there's no vector support for `__builtin_fmin` which is why I chose `__builtin_elementwise_min`. They appear to generate the same code so maybe I'm misunderstanding the difference between the two builtins.

> 
> > I note that the comments around the use of canonicalize mention sNAN, which isn't required by the spec.
> 
> The spec is quite badly written on what's expected of snans here, and the conformance test doesn't test what is written in the spec (hoping to fix that [here](https://github.com/KhronosGroup/OpenCL-CTS/pull/2285)

Thanks for the link. I was going by [7.2](https://registry.khronos.org/OpenCL/specs/3.0-unified/html/OpenCL_C.html#inf-nan-and-denormalized-numbers) but now I see there's also a [footnote](https://registry.khronos.org/OpenCL/specs/3.0-unified/html/OpenCL_C.html#_footnoteref_43).


https://github.com/llvm/llvm-project/pull/128506