On Mon, 15 Nov 2021 at 08:57, Matthias Kretz <m.kr...@gsi.de> wrote:

> ping. OK to push?
>

Sorry for the delay - this is OK for trunk.



> On Tuesday, 8 June 2021 14:12:23 CET Matthias Kretz wrote:
> > From: Matthias Kretz <kr...@kde.org>
> >
> > Explicitly support use of the stdx::simd implementation in situations
> > where the user links TUs that were compiled with different -m flags. In
> > general, this is always a (quasi) ODR violation for inline functions
> > because at least codegen may differ in important ways. However, in the
> > resulting executable only one (unspecified which one) of them might be
> > used. For simd we want to support users to compile code multiple times,
> > with different -m flags and have a runtime dispatch to the TU matching
> > the target CPU. But if internal functions are not inlined this may lead
> > to unexpected performance loss or execution of illegal instructions.
> > Therefore, inline functions that are not marked as always_inline must
> > use an additional template parameter somewhere in their name, to
> > disambiguate between the different -m translations.
> >
> > Signed-off-by: Matthias Kretz <m.kr...@gsi.de>
> >
> > libstdc++-v3/ChangeLog:
> >
> >       * include/experimental/bits/simd.h: Move feature detection bools
> >       and add __have_avx512bitalg, __have_avx512vbmi2,
> >       __have_avx512vbmi, __have_avx512ifma, __have_avx512cd,
> >       __have_avx512vnni, __have_avx512vpopcntdq.
> >       (__detail::__machine_flags): New function which returns a unique
> >       uint64 depending on relevant -m and -f flags.
> >       (__detail::__odr_helper): New type alias for either an anonymous
> >       type or a type specialized with the __machine_flags number.
> >       (_SimdIntOperators): Change template parameters from _Impl to
> >       _Tp, _Abi because _Impl now has an __odr_helper parameter which
> >       may be _OdrEnforcer from the anonymous namespace, which makes
> >       for a bad base class.
> >       (many): Either add __odr_helper template parameter or mark as
> >       always_inline.
> >       * include/experimental/bits/simd_detail.h: Add defines for
> >       AVX512BITALG, AVX512VBMI2, AVX512VBMI, AVX512IFMA, AVX512CD,
> >       AVX512VNNI, AVX512VPOPCNTDQ, and AVX512VP2INTERSECT.
> >       * include/experimental/bits/simd_builtin.h: Add __odr_helper
> >       template parameter or mark as always_inline.
> >       * include/experimental/bits/simd_fixed_size.h: Ditto.
> >       * include/experimental/bits/simd_math.h: Ditto.
> >       * include/experimental/bits/simd_scalar.h: Ditto.
> >       * include/experimental/bits/simd_neon.h: Add __odr_helper
> >       template parameter.
> >       * include/experimental/bits/simd_ppc.h: Ditto.
> >       * include/experimental/bits/simd_x86.h: Ditto.
> > ---
> >  libstdc++-v3/include/experimental/bits/simd.h | 380 ++++++++++++------
> >  .../include/experimental/bits/simd_builtin.h  |  41 +-
> >  .../include/experimental/bits/simd_detail.h   |  40 ++
> >  .../experimental/bits/simd_fixed_size.h       |  39 +-
> >  .../include/experimental/bits/simd_math.h     |  45 ++-
> >  .../include/experimental/bits/simd_neon.h     |   4 +-
> >  .../include/experimental/bits/simd_ppc.h      |   4 +-
> >  .../include/experimental/bits/simd_scalar.h   |  71 +++-
> >  .../include/experimental/bits/simd_x86.h      |   4 +-
> >  9 files changed, 440 insertions(+), 188 deletions(-)
>
> --
> ──────────────────────────────────────────────────────────────────────────
>  Dr. Matthias Kretz                           https://mattkretz.github.io
>  GSI Helmholtz Centre for Heavy Ion Research               https://gsi.de
>  stdₓ::simd
> ──────────────────────────────────────────────────────────────────────────
>
>
>
>

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