The r15-4321-gd8ef4471cb9c9f change incorrectly used __value as the member of the __memcpyable_integer trait, but it should have been __width. That meant this overload was not being used for _Tp != _Up.
Also return after doing the loop for the consteval case. The missing return wasn't causing incorrect behaviour because the consteval loop increments the iterator until it equals the end of the range, so the memset isn't done. But it's still better to return and not even try to do the memset. libstdc++-v3/ChangeLog: PR libstdc++/93059 * include/bits/stl_algobase.h (__fill_a1): Fix typo in SFINAE constraint. --- Tested x86_64-linux. Pushed to trunk. libstdc++-v3/include/bits/stl_algobase.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/libstdc++-v3/include/bits/stl_algobase.h b/libstdc++-v3/include/bits/stl_algobase.h index be311b91f53..fc7cc89736a 100644 --- a/libstdc++-v3/include/bits/stl_algobase.h +++ b/libstdc++-v3/include/bits/stl_algobase.h @@ -943,7 +943,7 @@ _GLIBCXX_END_NAMESPACE_CONTAINER inline typename __gnu_cxx::__enable_if<__is_byte<_Up>::__value && (__are_same<_Up, _Tp>::__value // for std::byte - || __memcpyable_integer<_Tp>::__value), + || __memcpyable_integer<_Tp>::__width), void>::__type __fill_a1(_Up* __first, _Up* __last, const _Tp& __x) { @@ -955,6 +955,7 @@ _GLIBCXX_END_NAMESPACE_CONTAINER { for (; __first != __last; ++__first) *__first = __val; + return; } #endif if (const size_t __len = __last - __first) -- 2.48.1