[SYCL][LIBCLC] Add sqrt for doubles for amdgcn-amdhsa

[npmiller]

No description provided.

[bader]

Does it make sense to add sqrt for fp16 as well?

[npmiller]

Does it make sense to add sqrt for fp16 as well?

Good point, I'll add it as well, it's just that I ran into an application using the double variant.

[bader]

Does it make sense to add sqrt for fp16 as well?

Good point, I'll add it as well, it's just that I ran into an application using the double variant.

Considering that typical built-in implementation for amdgcn-amdhsa target is a simple wrapper around a compiler built-in, adding implementation for all the types seems like a good rule to follow.

[npmiller]

Does it make sense to add sqrt for fp16 as well?

Good point, I'll add it as well, it's just that I ran into an application using the double variant.

Considering that typical built-in implementation for amdgcn-amdhsa target is a simple wrapper around a compiler built-in, adding implementation for all the types seems like a good rule to follow.

So I was testing this a bit further and the current change actually breaks the build, adding fp16 support seems a bit more involved than I thought.

This is because the default build, builds for the tahiti architecture, I reckon to have the lowest common denominator so libclc works on as many GPUs as possible, but that version of the ISA doesn't support fp16, so we'd need to update this version or add a way to change it at build time. In addition it seems that cl_khr_fp16 is defined anyway so we can't really use that right now in the code to skip the half variant for tahiti.

So we should probably leave out the half variant for now until we can setup half support for AMD in libclc properly.

[npmiller]

I just forced pushed to remove the commit adding the fp16 variant as it doesn't work, other commit is untouched, see previous comment for reasoning.