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 tree-optimization/114009] [11/12/13/14 Regression] Missed optimization: (!a) * a => 0 when a=(a/2)*2 Date: Tue, 05 Mar 2024 13:02:03 +0000 [thread overview] Message-ID: <bug-114009-4-gkQDofBcPw@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-114009-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114009 Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jakub at gcc dot gnu.org --- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Is the regression marker added for the r11-2550-gca2b8c082c4f16919071c9f8de8db0b33b54c405 change: movl %edi, %eax - xorl %edx, %edx + movl $0, %edx shrl $31, %eax addl %edi, %eax + addl $1, %edi andl $-2, %eax - sete %dl - imull %edx, %eax + cmpl $2, %edi + cmova %edx, %eax movl %eax, w(%rip) ret or for the r12-5392-g527e54a431473cc497204226a21f2831d2375e66 change: - movl %edi, %eax - movl $0, %edx - shrl $31, %eax - addl %edi, %eax - addl $1, %edi - andl $-2, %eax - cmpl $2, %edi - cmova %edx, %eax + leal 1(%rdi), %eax + movl %edi, %edx + cmpl $2, %eax + setbe %al + shrl $31, %edx + addl %edi, %edx + movzbl %al, %eax + sarl %edx + imull %edx, %eax + addl %eax, %eax or both? I don't think we ever optimized this without -fwrapv to just 0.
next prev parent reply other threads:[~2024-03-05 13:02 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-02-20 10:16 [Bug tree-optimization/114009] New: " 652023330028 at smail dot nju.edu.cn 2024-02-20 23:50 ` [Bug tree-optimization/114009] " pinskia at gcc dot gnu.org 2024-02-20 23:56 ` [Bug tree-optimization/114009] [11/12/13/14 Regression] " pinskia at gcc dot gnu.org 2024-02-21 0:03 ` pinskia at gcc dot gnu.org 2024-02-22 10:21 ` rguenth at gcc dot gnu.org 2024-03-05 13:02 ` jakub at gcc dot gnu.org [this message] 2024-03-05 14:14 ` jakub at gcc dot gnu.org 2024-03-05 14:24 ` jakub at gcc dot gnu.org 2024-03-07 7:47 ` cvs-commit at gcc dot gnu.org 2024-03-15 9:45 ` 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-114009-4-gkQDofBcPw@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).