* [PATCH] libstdc++: Add missing constexpr to simd_neon
@ 2023-05-23 21:57 Matthias Kretz
2023-05-24 11:02 ` Jonathan Wakely
0 siblings, 1 reply; 2+ messages in thread
From: Matthias Kretz @ 2023-05-23 21:57 UTC (permalink / raw)
To: gcc-patches, libstdc++
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Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
libstdc++-v3/ChangeLog:
PR libstdc++/109261
* include/experimental/bits/simd_neon.h (_S_reduce): Add
constexpr and make NEON implementation conditional on
not __builtin_is_constant_evaluated.
---
.../include/experimental/bits/simd_neon.h | 76 +++++++++----------
1 file changed, 36 insertions(+), 40 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_neon.h b/libstdc++-v3/include/experimental/bits/simd_neon.h
index 637b121b130..8f732d7587b 100644
--- a/libstdc++-v3/include/experimental/bits/simd_neon.h
+++ b/libstdc++-v3/include/experimental/bits/simd_neon.h
@@ -84,50 +84,46 @@ _S_masked_store_nocvt(_SimdWrapper<_Tp, _Np> __v, _Tp* __mem,
// }}}
// _S_reduce {{{
template <typename _Tp, typename _BinaryOperation>
- _GLIBCXX_SIMD_INTRINSIC static _Tp
+ _GLIBCXX_SIMD_INTRINSIC static constexpr _Tp
_S_reduce(simd<_Tp, _Abi> __x, _BinaryOperation&& __binary_op)
{
- constexpr size_t _Np = __x.size();
- if constexpr (sizeof(__x) == 16 && _Np >= 4
- && !_Abi::template _S_is_partial<_Tp>)
- {
- const auto __halves = split<simd<_Tp, simd_abi::_Neon<8>>>(__x);
- const auto __y = __binary_op(__halves[0], __halves[1]);
- return _SimdImplNeon<simd_abi::_Neon<8>>::_S_reduce(
- __y, static_cast<_BinaryOperation&&>(__binary_op));
- }
- else if constexpr (_Np == 8)
- {
- __x = __binary_op(__x, _Base::template _M_make_simd<_Tp, _Np>(
- __vector_permute<1, 0, 3, 2, 5, 4, 7, 6>(
- __x._M_data)));
- __x = __binary_op(__x, _Base::template _M_make_simd<_Tp, _Np>(
- __vector_permute<3, 2, 1, 0, 7, 6, 5, 4>(
- __x._M_data)));
- __x = __binary_op(__x, _Base::template _M_make_simd<_Tp, _Np>(
- __vector_permute<7, 6, 5, 4, 3, 2, 1, 0>(
- __x._M_data)));
- return __x[0];
- }
- else if constexpr (_Np == 4)
- {
- __x
- = __binary_op(__x, _Base::template _M_make_simd<_Tp, _Np>(
- __vector_permute<1, 0, 3, 2>(__x._M_data)));
- __x
- = __binary_op(__x, _Base::template _M_make_simd<_Tp, _Np>(
- __vector_permute<3, 2, 1, 0>(__x._M_data)));
- return __x[0];
- }
- else if constexpr (_Np == 2)
+ if (not __builtin_is_constant_evaluated())
{
- __x = __binary_op(__x, _Base::template _M_make_simd<_Tp, _Np>(
- __vector_permute<1, 0>(__x._M_data)));
- return __x[0];
+ constexpr size_t _Np = __x.size();
+ if constexpr (sizeof(__x) == 16 && _Np >= 4
+ && !_Abi::template _S_is_partial<_Tp>)
+ {
+ const auto __halves = split<simd<_Tp, simd_abi::_Neon<8>>>(__x);
+ const auto __y = __binary_op(__halves[0], __halves[1]);
+ return _SimdImplNeon<simd_abi::_Neon<8>>::_S_reduce(
+ __y, static_cast<_BinaryOperation&&>(__binary_op));
+ }
+ else if constexpr (_Np == 8)
+ {
+ __x = __binary_op(__x, _Base::template _M_make_simd<_Tp, _Np>(
+ __vector_permute<1, 0, 3, 2, 5, 4, 7, 6>(__x._M_data)));
+ __x = __binary_op(__x, _Base::template _M_make_simd<_Tp, _Np>(
+ __vector_permute<3, 2, 1, 0, 7, 6, 5, 4>(__x._M_data)));
+ __x = __binary_op(__x, _Base::template _M_make_simd<_Tp, _Np>(
+ __vector_permute<7, 6, 5, 4, 3, 2, 1, 0>(__x._M_data)));
+ return __x[0];
+ }
+ else if constexpr (_Np == 4)
+ {
+ __x = __binary_op(__x, _Base::template _M_make_simd<_Tp, _Np>(
+ __vector_permute<1, 0, 3, 2>(__x._M_data)));
+ __x = __binary_op(__x, _Base::template _M_make_simd<_Tp, _Np>(
+ __vector_permute<3, 2, 1, 0>(__x._M_data)));
+ return __x[0];
+ }
+ else if constexpr (_Np == 2)
+ {
+ __x = __binary_op(__x, _Base::template _M_make_simd<_Tp, _Np>(
+ __vector_permute<1, 0>(__x._M_data)));
+ return __x[0];
+ }
}
- else
- return _Base::_S_reduce(__x,
- static_cast<_BinaryOperation&&>(__binary_op));
+ return _Base::_S_reduce(__x, static_cast<_BinaryOperation&&>(__binary_op));
}
// }}}
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] libstdc++: Add missing constexpr to simd_neon
2023-05-23 21:57 [PATCH] libstdc++: Add missing constexpr to simd_neon Matthias Kretz
@ 2023-05-24 11:02 ` Jonathan Wakely
0 siblings, 0 replies; 2+ messages in thread
From: Jonathan Wakely @ 2023-05-24 11:02 UTC (permalink / raw)
To: Matthias Kretz; +Cc: gcc-patches, libstdc++
[-- Attachment #1: Type: text/plain, Size: 387 bytes --]
On Tue, 23 May 2023 at 22:57, Matthias Kretz via Libstdc++ <
libstdc++@gcc.gnu.org> wrote:
>
> Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
>
> libstdc++-v3/ChangeLog:
>
> PR libstdc++/109261
> * include/experimental/bits/simd_neon.h (_S_reduce): Add
> constexpr and make NEON implementation conditional on
> not __builtin_is_constant_evaluated.
>
OK
^ permalink raw reply [flat|nested] 2+ messages in thread
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