https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120931
--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> --- Started with r15-4473-g3abe751ea86e34 and this is the fix: --- a/libstdc++-v3/include/bits/stl_uninitialized.h +++ b/libstdc++-v3/include/bits/stl_uninitialized.h @@ -376,7 +376,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION std::__niter_base(__last), __x); else - std::__do_uninit_copy(__first, __last, __x); + std::__do_uninit_fill(__first, __last, __x); } // Overload for pointers.