public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
From: "segher at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/108757] We do not simplify (a - (N*M)) / N + M -> a / N Date: Sat, 11 Feb 2023 17:55:42 +0000 [thread overview] Message-ID: <bug-108757-4-5n4mF38Iy0@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-108757-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108757 --- Comment #6 from Segher Boessenkool <segher at gcc dot gnu.org> --- No? Take a=59 as counterexample: (a - (N*M)) / N + M = (59 - 2*30)/30 + 2 = ~0UL/30 + 2 but a / N = 59/30 = 1 Integer division in C is division towards zero, almost no normal algebraic simplifications apply there.
next prev parent reply other threads:[~2023-02-11 17:55 UTC|newest] Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-02-10 22:26 [Bug tree-optimization/108757] New: " bergner at gcc dot gnu.org 2023-02-10 22:28 ` [Bug tree-optimization/108757] " bergner at gcc dot gnu.org 2023-02-10 22:33 ` pinskia at gcc dot gnu.org 2023-02-10 22:40 ` pinskia at gcc dot gnu.org 2023-02-11 13:14 ` anlauf at gcc dot gnu.org 2023-02-11 16:38 ` segher at gcc dot gnu.org 2023-02-11 17:32 ` bergner at gcc dot gnu.org 2023-02-11 17:55 ` segher at gcc dot gnu.org [this message] 2023-02-11 18:05 ` bergner at gcc dot gnu.org 2023-02-11 18:15 ` segher at gcc dot gnu.org 2023-02-11 19:45 ` chip.kerchner at ibm dot com 2023-02-11 21:55 ` chip.kerchner at ibm dot com 2023-02-11 22:03 ` chip.kerchner at ibm dot com 2023-02-13 20:13 ` chip.kerchner at ibm dot com 2023-02-13 20:20 ` pinskia at gcc dot gnu.org 2023-02-13 20:27 ` [Bug rtl-optimization/108757] " pinskia at gcc dot gnu.org 2023-02-13 20:36 ` chip.kerchner at ibm dot com 2023-02-13 20:37 ` chip.kerchner at ibm dot com 2023-02-13 20:58 ` [Bug tree-optimization/108757] " pinskia at gcc dot gnu.org 2023-02-13 20:59 ` pinskia at gcc dot gnu.org 2023-02-13 21:01 ` pinskia at gcc dot gnu.org 2023-05-11 13:15 ` guojiufu at gcc dot gnu.org 2023-05-11 17:32 ` pinskia at gcc dot gnu.org 2023-05-12 1:52 ` guojiufu at gcc dot gnu.org 2023-05-12 6:25 ` guojiufu at gcc dot gnu.org 2023-05-12 9:35 ` guojiufu at gcc dot gnu.org 2023-09-04 2:46 ` cvs-commit at gcc dot gnu.org 2023-09-04 3:26 ` guojiufu 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-108757-4-5n4mF38Iy0@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).