http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49749
--- Comment #12 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-07-21 12:04:01 UTC --- + tree arg = gimple_phi_arg (stmt, i)->def; + if (TREE_CODE (arg) == SSA_NAME) + { + gimple def_stmt = SSA_NAME_DEF_STMT (arg); + if (def_stmt + && gimple_bb (def_stmt) arg = gimple_phi_arg_def (stmt, i); if (TREE_CODE (arg) == SSA_NAME && !SSA_NAME_IS_DEFAULT_DEF (arg)) { gimple def_stmt = SSA_NAME_DEF_STMT (arg); ... without the def_stmt != NULL and gimple_bb != NULL check.