public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/111284] [11/12/13/14 Regression] Some passing-by-value parameters are mishandled since GCC 9 Date: Tue, 05 Sep 2023 18:00:40 +0000 [thread overview] Message-ID: <bug-111284-4-3Zy5YygJ9W@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-111284-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111284 Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jason at gcc dot gnu.org --- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> --- private isn't needed. struct S { S () = default; constexpr S (const S &) noexcept : s{this} {} constexpr S & operator= (const S &) noexcept { return *this; } constexpr bool foo () const noexcept { return s == this; } S *s = this; }; constexpr bool bar (S x) noexcept { return x.foo (); } static_assert (bar (S {}), ""); static_assert ([] (S x) { return x.foo (); } (S {}), ""); The most important change in that commit was to make a copy of the inline body before it is destructively changed during genericization. On the other side, one of the important changes genericization does is adjust accesses to DECL_BY_REFERENCE PARM_DECLs/RESULT_DECLs. During the evaluation of static assert, I see we are first evaluating bar (&TARGET_EXPR <D.2583, <<< Unknown tree: aggr_init_expr 4 __ct_comp D.2583 (struct S *) <<< Unknown tree: void_cst >>> >>>>); which means that expression is adjusted for the passing of invisiref parms, we are passing there address of D.2583 variable with S type which is constructed. But, later on when trying to constexpr evaluate the body of bar, we see S::foo (&x); call, so passing address of x to the method, where x is PARM_DECL with S type. DECL_BY_REFERENCE even isn't set (yet) on it. I guess we need to somewhere during constexpr evaluation take into account that S pointer/reference has been passed to the function (to an invisiref parm) and the function body still uses it directly rather than changing it into a pointer/reference and dereferencing it.
next prev parent reply other threads:[~2023-09-05 18:00 UTC|newest] Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-09-04 11:16 [Bug c++/111284] New: Some passing-by-value parameters are miscompiled " de34 at live dot cn 2023-09-05 14:37 ` [Bug c++/111284] [11/12/13/14 Regression] Some passing-by-value parameters are mishandled " mpolacek at gcc dot gnu.org 2023-09-05 14:37 ` mpolacek at gcc dot gnu.org 2023-09-05 18:00 ` jakub at gcc dot gnu.org [this message] 2023-09-05 18:04 ` jakub at gcc dot gnu.org 2023-09-05 19:21 ` jakub at gcc dot gnu.org 2023-09-05 19:27 ` jakub at gcc dot gnu.org 2023-09-11 11:32 ` jakub at gcc dot gnu.org 2023-09-11 12:12 ` jakub at gcc dot gnu.org 2024-03-07 18:58 ` [Bug c++/111284] [11/12/13/14 Regression] Some passing-by-value parameters are mishandled since GCC 9, affecting libstdc++'s constexpr std::string jakub at gcc dot gnu.org 2024-03-11 15:12 ` ppalka at gcc dot gnu.org 2024-04-25 18:46 ` cvs-commit at gcc dot gnu.org 2024-04-25 18:48 ` [Bug c++/111284] [11/12/13 " jakub at gcc dot gnu.org 2024-05-09 4:26 ` cvs-commit at gcc dot gnu.org 2024-05-09 8:17 ` [Bug c++/111284] [11/12 " jakub at gcc dot gnu.org
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=bug-111284-4-3Zy5YygJ9W@http.gcc.gnu.org/bugzilla/ \ --to=gcc-bugzilla@gcc.gnu.org \ --cc=gcc-bugs@gcc.gnu.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).