From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 5C13F3858C1F; Wed, 12 Jul 2023 09:23:13 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 5C13F3858C1F DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1689153793; bh=VSp/fiNU6miB8XdHowWIIlP8NUg+c3/+p0m+xr2cMls=; h=From:To:Subject:Date:In-Reply-To:References:From; b=f17XYcpQx0j5lQujThuRMKOtwLODdRqN9YLE8xqrVJkR3P4GLxCBpv1xrtGuJP4La wKkd0+Ho5puyj5YOPj0gzvLzPxKidJsyVdxsUfT3PFSV694rUoz5YYOXcyKJr6cdaJ nMTf7pnB5lbm/b4Y8vxoDquKVnOB54Hn1YIj5Ujc= From: "gjl at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug target/110217] [avr] SREG: use BSET and BCLR instead of load/modify/write Date: Wed, 12 Jul 2023 09:23:11 +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: unknown X-Bugzilla-Keywords: missed-optimization X-Bugzilla-Severity: enhancement X-Bugzilla-Who: gjl 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: 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=3D110217 --- Comment #3 from Georg-Johann Lay --- At least CLI / SBI won't glitch at O0, same for ATOMIC_BLOCK. For SBI et al. you are right, they rely on insn combine. The right approach would have been compiler built-ins or API using inline asm. But the time to introduce such interfaces was 20 or so years ago...=