public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/109609] [12/13/14 Regression] tail call for function even when passing a ptr which references a local array still Date: Tue, 25 Apr 2023 07:06:08 +0000 [thread overview] Message-ID: <bug-109609-4-7AmjO1Cmye@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-109609-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109609 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |hubicka at gcc dot gnu.org --- Comment #10 from Richard Biener <rguenth at gcc dot gnu.org> --- On the first testcase reverting the offending rev. shows that it causes <bb 2> [local count: 137085152]: - MEM[(char *)&buf + 12B] = 0; - _19 = *id_8(D); - if (_19 != 0) + _18 = *id_7(D); + if (_18 != 0) thus we DSE the store to the end. The issue is that the fnspec we have for strncpy says the access size is specified by argument 3 but what it specified there is the _maximum_ size read, not the actual size. So instead of "1cO313" it should be "1cO31 " ('1' is somewhat odd then, it says we copy 'src' to 'dst' but we only say the 'dst' write covers arg 3 size - I guess that's OK for points-to analysis, the additional zeros written do not have pointers, but if we use it differently it might be a wrong spec?) I'm scanning other builtins for similar issues.
next prev parent reply other threads:[~2023-04-25 7:06 UTC|newest] Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-04-24 19:34 [Bug c++/109609] New: Invalid strncpy/strncat optimization in GCC 12 gburca-gnu at ebixio dot com 2023-04-24 19:38 ` [Bug middle-end/109609] " pinskia at gcc dot gnu.org 2023-04-24 19:40 ` pinskia at gcc dot gnu.org 2023-04-24 19:47 ` [Bug middle-end/109609] [12/13/14 Regression] " jakub at gcc dot gnu.org 2023-04-24 19:50 ` pinskia at gcc dot gnu.org 2023-04-24 19:52 ` [Bug middle-end/109609] [12/13/14 Regression] tail call for function even when passing a ptr which references a local array still jakub at gcc dot gnu.org 2023-04-24 19:56 ` pinskia at gcc dot gnu.org 2023-04-24 20:30 ` gburca-gnu at ebixio dot com 2023-04-24 20:52 ` jakub at gcc dot gnu.org 2023-04-25 6:30 ` rguenth at gcc dot gnu.org 2023-04-25 7:06 ` rguenth at gcc dot gnu.org [this message] 2023-04-25 7:15 ` rguenth at gcc dot gnu.org 2023-04-25 7:37 ` jakub at gcc dot gnu.org 2023-04-25 7:42 ` jakub at gcc dot gnu.org 2023-04-25 12:54 ` rguenth at gcc dot gnu.org 2023-04-25 14:53 ` cvs-commit at gcc dot gnu.org 2023-04-25 14:53 ` [Bug middle-end/109609] [12/13 " rguenth at gcc dot gnu.org 2023-04-25 16:14 ` gburca-gnu at ebixio dot com 2023-04-26 9:34 ` cvs-commit at gcc dot gnu.org 2023-04-26 10:41 ` cvs-commit at gcc dot gnu.org 2023-04-26 10:43 ` rguenth 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-109609-4-7AmjO1Cmye@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).