public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
From: "nathanael.schaeffer at gmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/114107] New: poor vectorization at -O3 when dealing with arrays of different multiplicity, good with -O2 Date: Sun, 25 Feb 2024 23:40:30 +0000 [thread overview] Message-ID: <bug-114107-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114107 Bug ID: 114107 Summary: poor vectorization at -O3 when dealing with arrays of different multiplicity, good with -O2 Product: gcc Version: 13.2.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: nathanael.schaeffer at gmail dot com Target Milestone: --- A simple loop multiplying two arrays, with different multiplicity fails to vectorize efficiently with -O3. Target is AVX x86_64. The loop is the following, where 4 consecutive values in data are multiplied by the same factor : for (int i=0; i<n; i++) { for (int k=0; k<4; k++) data[4*i+k] *= factor[i]; } See the very poor generated assembly with -O3 on godbolt, while the correct solution of a simple vbroadcastsd is generated by gcc 12.1+ with -O2 https://godbolt.org/z/fWj34bbhq
next reply other threads:[~2024-02-25 23:40 UTC|newest] Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-02-25 23:40 nathanael.schaeffer at gmail dot com [this message] 2024-02-25 23:46 ` [Bug target/114107] " pinskia at gcc dot gnu.org 2024-02-25 23:56 ` pinskia at gcc dot gnu.org 2024-02-26 0:12 ` nathanael.schaeffer at gmail dot com 2024-02-26 0:13 ` nathanael.schaeffer at gmail dot com 2024-02-26 0:27 ` pinskia at gcc dot gnu.org 2024-02-26 0:34 ` nathanael.schaeffer at gmail dot com 2024-02-26 2:51 ` liuhongt at gcc dot gnu.org 2024-02-26 3:28 ` liuhongt at gcc dot gnu.org 2024-02-26 7:42 ` nathanael.schaeffer at gmail dot com 2024-02-26 7:49 ` nathanael.schaeffer at gmail dot com 2024-02-26 7:54 ` liuhongt at gcc dot gnu.org 2024-02-26 8:13 ` nathanael.schaeffer at gmail dot com 2024-02-26 9:10 ` [Bug tree-optimization/114107] " rguenth at gcc dot gnu.org 2024-02-26 14:40 ` rguenth at gcc dot gnu.org 2024-06-13 6:22 ` cvs-commit at gcc dot gnu.org 2024-06-13 7:13 ` 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-114107-4@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).