From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id EBD853858C36; Wed, 6 Mar 2024 16:12:07 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org EBD853858C36 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1709741527; bh=YX4+vt0iSWGaCse2FZFSDXCi/JcfUlWnW7ywPmdLni0=; h=From:To:Subject:Date:In-Reply-To:References:From; b=YrvrYahEzVuuncYbiQDhRiDhi9Sgos1T4xuioGYMwleqtRG2Ma1j2r+hHphlNZ0MR P4SvtmYN9zZuifbMPBzPRnAuYb+69juwJR/rsWha+o2AQgsZ7qYRCUZZTZDk52lKp6 HOcOQ+5Yc1+I++R1uZ+TTvhq83CoaJ/5q7nRf8nw= From: "gjl at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug target/114252] Introducing bswapsi reduces code performance Date: Wed, 06 Mar 2024 16:12:07 +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: missed-optimization X-Bugzilla-Severity: normal X-Bugzilla-Who: gjl at gcc dot gnu.org X-Bugzilla-Status: NEW 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: 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=3D114252 --- Comment #5 from Georg-Johann Lay --- (In reply to Richard Biener from comment #4) > So bswap on a value is just register shuffling, right? The point is that there is no need for bswap in the first place, just have a look at the code that v13 generates. It's 4 QI loads and that's it, no shuffling required at all. But v14 dropped that, and the bswapsi (presumably due to previous flawed tr= ee optmizations) is introduced by some tree pass. There's nothing the backend can do about it. So would you explain why you think it's a "target" issue? Maybe the PR title I used is confusing and does not hit the point?=