[PATCH] libstdc++: Avoid ill-formed types on ARM

[PATCH] libstdc++: Avoid ill-formed types on ARM

[Matthias Kretz]

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Tested on arm-linux-gnueabihf, powerpc64le-linux-gnu, and aarch64-linux-gnu.

OK for trunk and backports?

----------------------------- 8< --------------------------

This resolves failing tests in check-simd.

Signed-off-by: Matthias Kretz <m.kretz@gsi.de>

libstdc++-v3/ChangeLog:

	PR libstdc++/114750
	* include/experimental/bits/simd_builtin.h
	(_SimdImplBuiltin::_S_load, _S_store): Fall back to copying
	scalars if the memory type cannot be vectorized for the target.
---
 libstdc++-v3/include/experimental/bits/simd_builtin.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)


--
──────────────────────────────────────────────────────────────────────────
 Dr. Matthias Kretz                           https://mattkretz.github.io
 GSI Helmholtz Centre for Heavy Ion Research               https://gsi.de
 stdₓ::simd
──────────────────────────────────────────────────────────────────────────

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diff --git a/libstdc++-v3/include/experimental/bits/simd_builtin.h b/libstdc++-v3/include/experimental/bits/simd_builtin.h
index 28227a5d97f..af0c4886108 100644
--- a/libstdc++-v3/include/experimental/bits/simd_builtin.h
+++ b/libstdc++-v3/include/experimental/bits/simd_builtin.h
@@ -1464,7 +1464,7 @@ _S_broadcast(_Tp __x) noexcept
 		   [&](auto __i) constexpr {
 		     return static_cast<_Tp>(__i < _Np ? __mem[__i] : 0);
 		   });
-	else if constexpr (sizeof(_Up) > 8)
+	else if constexpr (sizeof(_Up) > 8 or __vectorized_sizeof<_Up>() <= sizeof(_Up))
 	  return __generate_vector<_Tp, _SimdMember<_Tp>::_S_full_size>(
 		   [&](auto __i) constexpr _GLIBCXX_SIMD_ALWAYS_INLINE_LAMBDA {
 		     return static_cast<_Tp>(__i < _Np ? __mem[__i] : 0);
@@ -1536,7 +1536,7 @@ _S_masked_load(_SimdWrapper<_Tp, _Np> __merge, _MaskMember<_Tp> __k,
 	    for (size_t __i = 0; __i < _Np; ++__i)
 	      __mem[__i] = __v[__i];
 	  }
-	else if constexpr (sizeof(_Up) > 8)
+	else if constexpr (sizeof(_Up) > 8 or __vectorized_sizeof<_Up>() <= sizeof(_Up))
 	  __execute_n_times<_Np>([&](auto __i) constexpr _GLIBCXX_SIMD_ALWAYS_INLINE_LAMBDA {
 	    __mem[__i] = __v[__i];
 	  });

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Re: [PATCH] libstdc++: Avoid ill-formed types on ARM

[Jonathan Wakely]

On Wed, 17 Apr 2024 at 08:58, Matthias Kretz <m.kretz@gsi.de> wrote:
>
> Tested on arm-linux-gnueabihf, powerpc64le-linux-gnu, and aarch64-linux-gnu.
>
> OK for trunk and backports?

OK, thanks.


>
> ----------------------------- 8< --------------------------
>
> This resolves failing tests in check-simd.
>
> Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
>
> libstdc++-v3/ChangeLog:
>
>         PR libstdc++/114750
>         * include/experimental/bits/simd_builtin.h
>         (_SimdImplBuiltin::_S_load, _S_store): Fall back to copying
>         scalars if the memory type cannot be vectorized for the target.
> ---
>  libstdc++-v3/include/experimental/bits/simd_builtin.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
>
> --
> ──────────────────────────────────────────────────────────────────────────
>  Dr. Matthias Kretz                           https://mattkretz.github.io
>  GSI Helmholtz Centre for Heavy Ion Research               https://gsi.de
>  stdₓ::simd
> ──────────────────────────────────────────────────────────────────────────