https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115575
--- Comment #4 from Matthias Kretz (Vir) <mkretz at gcc dot gnu.org> --- The test fails on x86_64 because the effective target selector 'avx512f' is always true. Thus on non-AVX512 systems the test fails with 'illegal instruction(s)'. That's a different issue than on SPARC, where it aborts with a bogus value. On SPARC vectorization of SIMD is actually disabled. Thus an '<int, 4>' mask is a bitmask of 4 bits (a 'fixed_size_simd_mask'). Now, looking back at my fixed_size implementation, the mask stores a _SanitizedBitMask. IOW, it assumes the bit mask padding bits are always zero. Consequently, the memcpy in 'reduce2()' in the new test violates the invariant of fixed_size_simd_mask. The test itself is the bug. necessary changes: 1. compile with '-march=x86_64-v4' only with 'avx512f_runtime'. 2. add another constexpr-if condition in 'reduce2()' to skip fixed_size ABIs
