Re: [Questions] Is there any bit in gimple/rtl to indicate this IR support fast-math or not?

[Hongtao Liu <crazylht@gmail.com>]

On Wed, Jul 14, 2021 at 2:39 PM Matthias Kretz <m.kretz@gsi.de> wrote:
>
> On Wednesday, 14 July 2021 07:18:29 CEST Hongtao Liu via Gcc-help wrote:
> > On Wed, Jul 14, 2021 at 1:15 PM Hongtao Liu <crazylht@gmail.com> wrote:
> > > Hi:
> > >   The original problem was that some users wanted the cmdline option
> > >
> > > -ffast-math not to act on intrinsic production code.
>
> This sounds like the users want intrinsics to map *directly* to the
Thanks for the reply.
I think the users want the mixed usage of fast-math and no-fast-math.
> corresponding instruction. If that's the case such users should use inline
> assembly, IMHO. If you compile a TU with -ffast-math then *all* floating-point
> operations are affected. Yes, more control over where to use fast-math and the
> ability to mix fast-math and no-fast-math without risking ODR violations would
> be great. But that's a larger issue, and one that would ideally be solved in
> WG14/WG21.
hmm, guess it would need a lot of work.
>
> FWIW, this is what I'd do, i.e. turn off fast-math for the function in
> question:
> https://godbolt.org/z/3cKq5hT1o
>
> --
> ──────────────────────────────────────────────────────────────────────────
>  Dr. Matthias Kretz                           https://mattkretz.github.io
>  GSI Helmholtz Centre for Heavy Ion Research               https://gsi.de
>  std::experimental::simd              https://github.com/VcDevel/std-simd
> ──────────────────────────────────────────────────────────────────────────



-- 
BR,
Hongtao