From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 918B93858C54; Thu, 11 May 2023 14:33:50 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 918B93858C54 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1683815630; bh=Axin9TLP9IZ3TdJSUmSSajuOqvvVvWlYnDhUimsZ6yk=; h=From:To:Subject:Date:In-Reply-To:References:From; b=lIndvnaTzXjU9TsbB1EERHEvqldxilvwcucVLjai+e/afY4Bf6e+T0CVFerYE8BGR war1GSAsi4X/GViggjeC/11dZRvbdPpeFGISPLGpAsEO2jrp5JxyeddVyA63flpwZ6 pd638PWzfZZod/qQwjyy5Ls6QyUFPOw4wmBUXV24= From: "law at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/109592] Failure to recognize shifts as sign/zero extension Date: Thu, 11 May 2023 14:33:50 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: rtl-optimization X-Bugzilla-Version: 13.0 X-Bugzilla-Keywords: missed-optimization X-Bugzilla-Severity: normal X-Bugzilla-Who: law 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=3D109592 --- Comment #6 from Jeffrey A. Law --- I would still rather not introduce special cases for SUBREGs if we can avoid it. I think the question remains whether or not patching simplify-rtx's canonicalize_shift is sufficient to fix this problem (perhaps with the adjustment to fwprop as well). If they are, then they would be much prefer= red over the original patch which special cased SUBREGs.=