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

Wed Dec 12 02:03:52 PST 2018

rengolin added a comment.

In D53927#1328003 <https://reviews.llvm.org/D53927#1328003>, @shibatch wrote:

> > Where, when, how and by whom are these #pragmas inserted? Are they silently inserted by clang? Do they have to be manually inserted in existing code?
> >  What is the effect of these #pragmas? The ARM closed-source commercial compiler requires OpenMP. How will these #pragmas be implemented in the open-source clang? Will they import OpenMP interfaces in the open-source clang as well?
> >  If importing OpenMP interfaces is not triggered by the insertion of these #pragmas, why is the argument to -fveclib called 'openmp'? I would find it baffling to have to type -fveclib=openmp on compile-line, but ending up not using OpenMP.
>
> I think you should post these questions as a reply to the RFC.

Yes, but bear in mind that the proprietary compiler options will always have less weight than other OSS compilers.

Putting it bluntly, if it doesn't work in GCC, people will not use it. Regardless of what any proprietary compiler does, based or not in LLVM.

We already have some clang pragmas for vectorisation, we don't need yet another syntax, and if we do, we should use OpenMPs.

Using OMP pragmas doesn't necessarily means we need to link with OMP libraries, and that's a special case for OMP SIMD.

Any new pragma MUST be done though an RFC process in the llvm-dev list, that's for sure.

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  https://reviews.llvm.org/D53927/new/

https://reviews.llvm.org/D53927