[llvm-dev] [RFC][VECLIB] how should we legalize VECLIB calls?

[Renato Golin via llvm-dev]

On Wed, 10 Oct 2018 at 21:18, Francesco Petrogalli
<Francesco.Petrogalli at arm.com> wrote:
> I am not sure I understand this. Are you saying that the signature of __svml_sin_8 might not conform to the signature that the intel vector function ABI mandates for a 8 lanes version of sin operating on double?
> Or is it just a difference in names that raises concerns for SVML? If the latter, I believe that the problem is easily solvable with OpenMP5.0. If the former, it gets indeed more complicated.

Neither. :)

My point is that GNU, Arm, Intel, IBM (usually) publish documents
outlining their ABIs and they tend to stick to them. Not all library
vendors do, or need to.

Tracking changes in the stable ABIs is a long process and everyone
pays the cost, but tracking (perhaps more frequent and unpredictable)
changes in some other libraries could not only mean trunk (or maybe
even a release) will have broken support for some library (that we
officially support), but also it could increase the cost of
maintaining (and identifying) all past variants and applying the
correct ones.

I don't personally know how stable SVML, SLEEF and others are, and how
much of a standardisation process they have, so the comment may be
moot. But it's a point to consider for all libraries once we introduce
a more "generic" way of replacing functions that still needs compiler
support (ie. not OMP5).

--renato