On Mon, 22 Apr 2024 at 16:30, Matthias Kretz <m.kr...@gsi.de> wrote:
>
> Tested on x86_64-linux-gnu, powerpc64le-linux-gnu, aarch64-linux-gnu, arm-
> linux-gnueabihf
>
> OK for trunk and backports?
OK, thanks
>
> ----------------------------- 8< ---------------------------------
>
>
> Avoid
> -Wnarrowing in C code;
> -Wtautological-compare in unconditional static_assert (necessary for
> faking a dependency on a template parameter)
>
> Signed-off-by: Matthias Kretz <m.kr...@gsi.de>
>
> libstdc++-v3/ChangeLog:
>
> * include/experimental/bits/simd.h: Ignore -Wnarrowing for
> arm_neon.h.
> (__int_for_sizeof): Replace tautological compare with checking
> for invalid template parameter value.
> * include/experimental/bits/simd_builtin.h (__extract_part):
> Remove tautological compare by combining two static_assert.
> ---
> libstdc++-v3/include/experimental/bits/simd.h | 8 +++++++-
> libstdc++-v3/include/experimental/bits/simd_builtin.h | 3 +--
> 2 files changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/libstdc++-v3/include/experimental/bits/simd.h b/libstdc++-v3/
> include/experimental/bits/simd.h
> index 03c2e17a326..6ef9c955cfa 100644
> --- a/libstdc++-v3/include/experimental/bits/simd.h
> +++ b/libstdc++-v3/include/experimental/bits/simd.h
> @@ -44,7 +44,12 @@
> #if _GLIBCXX_SIMD_X86INTRIN
> #include <x86intrin.h>
> #elif _GLIBCXX_SIMD_HAVE_NEON
> +#pragma GCC diagnostic push
> +// narrowing conversion of '__a' from 'uint64_t' {aka 'long long unsigned
> int'} to
> +// 'int64x1_t' {aka 'long long int'} [-Wnarrowing]
> +#pragma GCC diagnostic ignored "-Wnarrowing"
> #include <arm_neon.h>
> +#pragma GCC diagnostic pop
> #endif
> #if _GLIBCXX_SIMD_HAVE_SVE
> #include <arm_sve.h>
> @@ -598,6 +603,7 @@ struct __is_bitmask
> constexpr auto
> __int_for_sizeof()
> {
> + static_assert(_Bytes > 0);
> if constexpr (_Bytes == sizeof(int))
> return int();
> #ifdef __clang__
> @@ -663,7 +669,7 @@ struct _Ip
> return _Ip{};
> }
> else
> - static_assert(_Bytes != _Bytes, "this should be unreachable");
> + static_assert(_Bytes == 0, "this should be unreachable");
> }
> #pragma GCC diagnostic pop
>
> diff --git a/libstdc++-v3/include/experimental/bits/simd_builtin.h b/libstdc+
> +-v3/include/experimental/bits/simd_builtin.h
> index af0c4886108..49c7c7e1c70 100644
> --- a/libstdc++-v3/include/experimental/bits/simd_builtin.h
> +++ b/libstdc++-v3/include/experimental/bits/simd_builtin.h
> @@ -278,8 +278,7 @@ __extract_part(const _SimdWrapper<_Tp, _Np> __x)
> __extract_part(const _SimdWrapper<bool, _Np> __x)
> {
> static_assert(_Combine == 1, "_Combine != 1 not implemented");
> - static_assert(__have_avx512f && _Np == _Np);
> - static_assert(_Total >= 2 && _Index + _Combine <= _Total && _Index >= 0);
> + static_assert(__have_avx512f && _Total >= 2 && _Index + _Combine <=
> _Total && _Index >= 0);
> return __x._M_data >> (_Index * _Np / _Total);
> }
>
> --
> ──────────────────────────────────────────────────────────────────────────
> Dr. Matthias Kretz https://mattkretz.github.io
> GSI Helmholtz Centre for Heavy Ion Research https://gsi.de
> stdₓ::simd
> ──────────────────────────────────────────────────────────────────────────
>
