https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109949
--- Comment #4 from Matthias Kretz (Vir) <mkretz at gcc dot gnu.org> --- With -mcpu=power10 I see the issue. The problem has been there all the time and only surfaced with this test. (It should also have shown on `make check-simd` in libstdc++.)