From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 626093858430; Mon, 22 Jan 2024 16:55:54 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 626093858430 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1705942554; bh=DFKpouDUiR57nAEF5XoZOGuYcy1GKK4bg5CkNroPFmU=; h=From:To:Subject:Date:In-Reply-To:References:From; b=WF1hEaDXK+KJ9uQXVf66F7VTnCfYIMCz36H+paastdUAPY8Qrpj9Rvo9PhtFiKj8d szEnzZLN81fwtU8ZIB3SUeyEonBI7+NvJK0JzSqu9AUfxMBWiKHad43gqAbMGLMeFV B9QzI2B6I8UKmRG0AXrEdzvCf/wOn7Sw98J1KRBQ= From: "pinskia at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug target/113543] Poor codegen for bit-counting functions (countl_zero, countl_one, countr_zero, countr_one) Date: Mon, 22 Jan 2024 16:55:54 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: target X-Bugzilla-Version: 14.0 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: pinskia at gcc dot gnu.org X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: component Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 List-Id: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D113543 Andrew Pinski changed: What |Removed |Added ---------------------------------------------------------------------------- Component|c++ |target --- Comment #1 from Andrew Pinski --- >Clang does not emit the extra xor instruction. I don't really know why.=20 This is a performance errata in some Intel cores and GCC implements that wh= ile LLVM/clang does NOT. See PR 62011 on that.=