https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94041
--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jason Merrill <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:ce0ab8fb46f07b0bde56aa31e46d57b81379fde3 commit r12-6327-gce0ab8fb46f07b0bde56aa31e46d57b81379fde3 Author: Jason Merrill <ja...@redhat.com> Date: Thu Mar 5 15:50:45 2020 -0500 c++: temporary lifetime with aggregate init [PR94041] In C++98 the lifetime of temporaries in aggregate initialization was unclear, but C++11 DR201 clarified that only temporaries created for default-initialization of an array element with no corresponding initializer-clause are destroyed immediately; all others persist until the end of the full-expression. But we never implemented that, and continued treating individual element initializations as full-expressions, such as in my patch for PR50866 in r180442. This blocked my attempted fix for PR66139, which extended the use of split_nonconstant_init, and thus the bug, to aggregate initialization of temporaries within an expression. The longer temporary lifetime creates further EH region overlap problems like the ones that wrap_temporary_cleanups addresses: in aggr7.C, we start out with a normal nesting of A1 c.b1 A2 c.b2 ... ~A2 ~A1 where on the way in, throwing from one of the inits will clean up from the previous inits. But once c.b2 is initialized, throwing from ~A2 must not clean up c.b1; instead it needs to clean up c. So as in build_new_1, we deal with this by guarding the B cleanups with flags that are cleared once c is fully constructed; throwing from one of the ~A still hits that region, but does not call ~B. And then wrap_temporary_cleanups deals with calling ~C, but we need to tell it not to wrap the subobject cleanups. The change from expressing the subobject cleanups with CLEANUP_STMT to TARGET_EXPR was also necessary because we need them to collate with the ~A in gimplify_cleanup_point_expr; the CLEANUP_STMT representation only worked with treating subobject initializations as full-expressions. PR c++/94041 gcc/cp/ChangeLog: * decl.c (check_initializer): Remove obsolete comment. (wrap_cleanups_r): Don't wrap CLEANUP_EH_ONLY. (initialize_local_var): Change assert to test. * typeck2.c (maybe_push_temp_cleanup): New. (split_nonconstant_init_1): Use it. (split_nonconstant_init): Clear cleanup flags. gcc/testsuite/ChangeLog: * g++.dg/init/aggr7-eh.C: New test. * g++.dg/cpp0x/initlist122.C: Also test aggregate variable.
