From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 4DB523851C31; Tue, 2 Jun 2020 12:55:09 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 4DB523851C31 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1591102509; bh=CTy+ha28m+C2K7e939vwLiv6Ae0XD9vZssV/NCxhH04=; h=From:To:Subject:Date:In-Reply-To:References:From; b=UrZC/iLtP8BDaTGJ8q/Uf+o8Ro/uVqdPzTGh1IDTAOTgEquTdnKPtyp6bGZLZIXHa 8Pqbcle2SL4Ix9s+3AMZE3MnfA1Tk3PP0EtiD2dxwR+LGhnK3E+xqJKftlsHPQn6Z5 DgDtX78SPZklU4BZRrwqWrqZHidWkSlFi5DSq198= From: "hjl.tools at gmail dot com" To: gcc-bugs@gcc.gnu.org Subject: [Bug target/95237] LOCAL_DECL_ALIGNMENT shrinks alignment, FAIL gcc.target/i386/pr69454-2.c Date: Tue, 02 Jun 2020 12:55:09 +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: 11.0 X-Bugzilla-Keywords: ice-on-valid-code, wrong-code X-Bugzilla-Severity: normal X-Bugzilla-Who: hjl.tools at gmail dot com X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: skpgkp2 at gmail dot com X-Bugzilla-Target-Milestone: 11.0 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 X-BeenThere: gcc-bugs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-bugs mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 02 Jun 2020 12:55:09 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D95237 --- Comment #10 from H.J. Lu --- (In reply to rguenther@suse.de from comment #9) > > The i386 psABI specifies 4 byte alignment for long long. But we want to > > use 8 byte alignment if there is no ABI implication and no stack realig= nment > > is needed. Will ROUND_TYPE_ALIGN always align long long to 8 bytes? >=20 > So what we want here is RTL expansion pad out stack slots if they know > to be aligned but not adjust DECL_ALIGN. Not sure if there's already > a target hook to pad out variables, if not this may be the way to get > what you desire here. >=20 > I guess the actual reason is crossing of cache-lines? If the incoming stack is 4 byte aligned, we can't align long long to 8 bytes without stack realignment.=