https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105769
--- Comment #11 from Jakub Jelinek <jakub at gcc dot gnu.org> --- struct S { S *p; S *q; S () {} ~S (); }; void bar (S *); void foo () { S a, b; bar (nullptr); { S c; c.p = &a; c.q = &b; bar (&c); } bar (nullptr); } at -O2 gets roughly the same stuff in the IL with taking address of a and b being done before a and b is clobbered, then c being clobbered, initialized, eol clobbered and only then a and b destructed and eol clobbered. But for some reason no stack sharing happens in that case.