[libclc] [libclc] Move conversion builtins to the CLC library (PR #124727)

[Fraser Cormack via cfe-commits]

frasercrmck wrote:

> I think for `clspv`, we would need to invert the condition to skip user-facing functions. By that I mean that `clspv` will need all the `convert_*` functions, and not the `__clc_convert_*_rte`. Then we will need to update `clspv` to support natively the function with the `__clc_` prefix.

Oh dear - thanks for trying out the PR so promptly.

I fear that if clspv doesn't provide (e.g.) `__clc_convert_*_rte` then no other CLC function would be able to call that for its own implementation. The CLC library should be internally self-sufficient. The idea here is that the CLC maths functions will need to make use of CLC conversion functions, and not call out to OpenCL. That's why the current user-facing skips are as they are. It seems that I've missed something fundamental here.

I think I may need to try out clspv for myself so I get a better idea of what's going wrong.

https://github.com/llvm/llvm-project/pull/124727