https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109261
--- Comment #16 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-13 branch has been updated by Matthias Kretz <mkr...@gcc.gnu.org>: https://gcc.gnu.org/g:dad9abd7daa1d977e79af7ac76c17c91464aca08 commit r13-7375-gdad9abd7daa1d977e79af7ac76c17c91464aca08 Author: Matthias Kretz <m.kr...@gsi.de> Date: Thu Mar 23 09:32:58 2023 +0100 libstdc++: Add missing constexpr to simd The constexpr API is only available with -std=gnu++XX (and proposed for C++26). The proposal is to have the complete simd API usable in constant expressions. This patch resolves several issues with using simd in constant expressions. Issues why constant_evaluated branches are necessary: * subscripting vector builtins is not allowed in constant expressions * if the implementation needs/uses memcpy * if the implementation would otherwise call SIMD intrinsics/builtins Signed-off-by: Matthias Kretz <m.kr...@gsi.de> libstdc++-v3/ChangeLog: PR libstdc++/109261 * include/experimental/bits/simd.h (_SimdWrapper::_M_set): Avoid vector builtin subscripting in constant expressions. (resizing_simd_cast): Avoid memcpy if constant_evaluated. (const_where_expression, where_expression, where) (__extract_part, simd_mask, _SimdIntOperators, simd): Add either _GLIBCXX_SIMD_CONSTEXPR (on public APIs), or constexpr (on internal APIs). * include/experimental/bits/simd_builtin.h (__vector_permute) (__vector_shuffle, __extract_part, _GnuTraits::_SimdCastType1) (_GnuTraits::_SimdCastType2, _SimdImplBuiltin) (_MaskImplBuiltin::_S_store): Add constexpr. (_CommonImplBuiltin::_S_store_bool_array) (_SimdImplBuiltin::_S_load, _SimdImplBuiltin::_S_store) (_SimdImplBuiltin::_S_reduce, _MaskImplBuiltin::_S_load): Add constant_evaluated case. * include/experimental/bits/simd_fixed_size.h (_S_masked_load): Reword comment. (__tuple_element_meta, __make_meta, _SimdTuple::_M_apply_r) (_SimdTuple::_M_subscript_read, _SimdTuple::_M_subscript_write) (__make_simd_tuple, __optimize_simd_tuple, __extract_part) (__autocvt_to_simd, _Fixed::__traits::_SimdBase) (_Fixed::__traits::_SimdCastType, _SimdImplFixedSize): Add constexpr. (_SimdTuple::operator[], _M_set): Add constexpr and add constant_evaluated case. (_MaskImplFixedSize::_S_load): Add constant_evaluated case. * include/experimental/bits/simd_scalar.h: Add constexpr. * include/experimental/bits/simd_x86.h (_CommonImplX86): Add constexpr and add constant_evaluated case. (_SimdImplX86::_S_equal_to, _S_not_equal_to, _S_less) (_S_less_equal): Value-initialize to satisfy constexpr evaluation. (_MaskImplX86::_S_load): Add constant_evaluated case. (_MaskImplX86::_S_store): Add constexpr and constant_evaluated case. Value-initialize local variables. (_MaskImplX86::_S_logical_and, _S_logical_or, _S_bit_not) (_S_bit_and, _S_bit_or, _S_bit_xor): Add constant_evaluated case. * testsuite/experimental/simd/pr109261_constexpr_simd.cc: New test. (cherry picked from commit da579188807ede4ee9466d0b5bf51559c96a0b51)
