[PATCH] D53927: [AArch64] Enable libm vectorized functions via SLEEF

Tue Dec 11 07:06:35 PST 2018

rengolin added a comment.

In D53927#1326908 <https://reviews.llvm.org/D53927#1326908>, @shibatch wrote:

> > Today, we don't have SVE, so we don't generate SVE bindings, all fine. Say, next year you upstream SVE bindings in SLEEF and then change LLVM to emit those too.
>
> SLEEF already has support for SVE.

I see, but the point is still the same.

Implementation will evolve, new functions will be added, and testing all variants will still lead to the same maintenance issues.

The bottom line is: this is a long term commitment, and I want to make sure everyone involved is aware of that.

> This is also a problem in SVML.

Yes, and Intel has been very forthcoming in maintaining their code.

> My understanding is that this patch is kind of tentative, which will be used until the OpenMP patch ( https://reviews.llvm.org/D54412 ) will be merged.
>  After that, the include file that is contained in the vector math library is referred by the compiler to see which math functions are available. So this problem won't occur.

In that case, I propose we either make this experimental, or we wait until that patch lands and we can change this one accordingly.

I am worried to walk into a situation where we generate OpenMP code where no pragmas were written, as we don't (and shouldn't) include libomp by default.

I know this patch doesn't do that, but some of the comments here and there make allusion to that fact, and we should be careful how we proceed.

I would welcome @hfinkel's opinion.

Repository:
  rL LLVM

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D53927/new/

https://reviews.llvm.org/D53927