https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62026
--- Comment #14 from Jan Hubicka <hubicka at gcc dot gnu.org> --- I am testing the following for 4.9-branch: Index: cgraphclones.c =================================================================== --- cgraphclones.c (revision 215890) +++ cgraphclones.c (working copy) @@ -310,6 +310,8 @@ duplicate_thunk_for_node (cgraph_node *t if (thunk_of->thunk.thunk_p) node = duplicate_thunk_for_node (thunk_of, node); + cgraph_get_body (thunk); + struct cgraph_edge *cs; for (cs = node->callers; cs; cs = cs->next_caller) if (cs->caller->thunk.thunk_p Index: lto-streamer-out.c =================================================================== --- lto-streamer-out.c (revision 215890) +++ lto-streamer-out.c (working copy) @@ -2077,7 +2077,10 @@ lto_output (void) #endif decl_state = lto_new_out_decl_state (); lto_push_out_decl_state (decl_state); - if (gimple_has_body_p (node->decl) || !flag_wpa) + if (gimple_has_body_p (node->decl) || !flag_wpa + /* Thunks have no body but they may be synthetized + at WPA time. */ + || DECL_ARGUMENTS (node->decl)) output_function (node); else copy_function (node);