From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 8FA213851404; Wed, 26 Jan 2022 17:08:54 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 8FA213851404 From: "rdapp at linux dot ibm.com" To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/104198] [12 regression] ifcvf change breaks 64-bit SPARC bootstrap Date: Wed, 26 Jan 2022 17:08:54 +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: 12.0 X-Bugzilla-Keywords: build, wrong-code X-Bugzilla-Severity: normal X-Bugzilla-Who: rdapp at linux dot ibm.com X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P1 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: 12.0 X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: attachments.created 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: Wed, 26 Jan 2022 17:08:54 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D104198 --- Comment #10 from rdapp at linux dot ibm.com --- Created attachment 52297 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=3D52297&action=3Dedit Tentative patch I now have something that successfully bootstraps on s390x, PowerPC and SPA= RC but I'm not really happy with it. The idea is basically to check if the newly introduced sequence (getting pa= ssed a cc comparison) emits an instruction other than the movcc that reads a register used in the comparison. I'm not sure what backends are supposed to emit for such a sequence but most likely everything is admissible.=20 reg_overlap_mentioned_p does not handle every rtx_code so special handling = is necessary which needs to be exhaustive in order for reg_overlap_mentioned_p= not to ICE. I feel like this is not the best way to achieve what we want and would appreciate some insight. I attached the current full diff to master (inclu= ding the fix for the problem triggered by the or1k backend. It's pretty raw/unpolished/ugly but the idea should come across. A full testsuite run on gcc202 just finished, 83 FAILs, but I haven't yet d= one a comparison run from before the ifcvt changes.=