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@xxxxxxxxx> 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 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. 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 ──────────────────────────────────────────────────────────────────────────
