[libclc] [libclc] Move sign to the CLC builtins library (PR #115699)

[Fraser Cormack via cfe-commits]

frasercrmck wrote:

@arsenm I've just updated this PR. It still moves the `sign` implementation to the CLC library but now also optimizes it for vector types. There's no control flow nor scalarizing for vectors. I trust this will be a good enough default for the scalar form (on GPUs) though I suppose CPUs may prefer the old control flow form. I doubt any would prefer the old vector form, though.

alive2 seems to be happy with the transformation (for `half2`): https://alive2.llvm.org/ce/z/RZ8Dc4

Let me know what you think.

https://github.com/llvm/llvm-project/pull/115699