https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103562
--- Comment #4 from Martin Liška <marxin at gcc dot gnu.org> --- Honza's investigation on IRC: <honza_home> Looks like inlining did not understand the return slot optimization, so it simply stores the value to <retslot> that is presumably now a normal variable. <honza_home> so I guess missing DECL_BY_REFERENCE flag on the return value decl?