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From: "cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/98463] [11 Regression] internal compiler error: in output_constructor_regular_field, at varasm.c:5491 by r11-2720 Date: Tue, 26 Jan 2021 20:01:52 +0000 [thread overview] Message-ID: <bug-98463-4-VpbHH7QtuP@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-98463-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98463 --- Comment #13 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jason Merrill <jason@gcc.gnu.org>: https://gcc.gnu.org/g:a4dfd0f089af33f2af57bf422f9859405b9b4a16 commit r11-6918-ga4dfd0f089af33f2af57bf422f9859405b9b4a16 Author: Jason Merrill <jason@redhat.com> Date: Sun Jan 24 00:55:49 2021 -0500 c++: constexpr and empty fields [PR97566] In the discussion of PR98463, Jakub pointed out that in C++17 and up, cxx_fold_indirect_ref_1 could use the field we build for an empty base. I tried implementing that, but it broke one of the tuple tests, so I did some more digging. To start with, I generalized the PR98463 patch to handle the case where we do have a field, for an empty base or [[no_unique_address]] member. This is enough also for the no-field case because the member of the empty base must itself be an empty field; if it weren't, the base would not be empty. I looked for related PRs and found 97566, which was also fixed by the patch. After some poking around to figure out why, I noticed that the testcase had been breaking because E, though an empty class, has an ABI nvsize of one byte, and we were giving the [[no_unique_address]] FIELD_DECL that DECL_SIZE, whereas in build_base_field_1 empty base fields always get DECL_SIZE zero, and various places were relying on that to recognize empty fields. So I adjusted both the size and the checking. When I adjusted check_bases I wondered if we were correctly handling bases with only empty data members, but it appears we do. I'm deferring the cxx_fold_indirect_ref_1 change until stage 1, as I don't think it actually fixes anything. gcc/cp/ChangeLog: PR c++/97566 PR c++/98463 * class.c (layout_class_type): An empty field gets size 0. (is_empty_field): New. (check_bases): Check it. * cp-tree.h (is_empty_field): Declare it. * constexpr.c (cxx_eval_store_expression): Check it. (cx_check_missing_mem_inits): Likewise. * init.c (perform_member_init): Likewise. * typeck2.c (process_init_constructor_record): Likewise. gcc/testsuite/ChangeLog: PR c++/97566 * g++.dg/cpp2a/no_unique_address10.C: New test. * g++.dg/cpp2a/no_unique_address9.C: New test.
next prev parent reply other threads:[~2021-01-26 20:01 UTC|newest] Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-12-28 15:18 [Bug c++/98463] New: [11 Regression] internal compiler error: in output_constructor_regular_field, at varasm.c:5491 romain.geissler at amadeus dot com 2020-12-28 19:55 ` [Bug c++/98463] [11 Regression] internal compiler error: in output_constructor_regular_field, at varasm.c:5491 by r11-2720 hjl.tools at gmail dot com 2020-12-28 20:32 ` redi at gcc dot gnu.org 2020-12-29 13:56 ` romain.geissler at amadeus dot com 2021-01-05 10:41 ` rguenth at gcc dot gnu.org 2021-01-07 12:22 ` jakub at gcc dot gnu.org 2021-01-07 13:08 ` jakub at gcc dot gnu.org 2021-01-07 13:42 ` jakub at gcc dot gnu.org 2021-01-07 16:58 ` jakub at gcc dot gnu.org 2021-01-13 16:29 ` jakub at gcc dot gnu.org 2021-01-14 11:14 ` rguenth at gcc dot gnu.org 2021-01-19 12:52 ` rguenth at gcc dot gnu.org 2021-01-21 21:24 ` mpolacek at gcc dot gnu.org 2021-01-24 5:51 ` jason at gcc dot gnu.org 2021-01-25 15:38 ` cvs-commit at gcc dot gnu.org 2021-01-25 16:12 ` jason at gcc dot gnu.org 2021-01-26 20:01 ` cvs-commit at gcc dot gnu.org [this message] 2021-01-29 16:00 ` cvs-commit at gcc dot gnu.org
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