From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id A56A0384AB76; Tue, 14 May 2024 15:24:51 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org A56A0384AB76 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1715700291; bh=0i15wu1cQecrFqzGVjnTl6gadN/EEvp8DdK92xRL0bA=; h=From:To:Subject:Date:In-Reply-To:References:From; b=dS9FnCTL7uGIEXKnoLmKy0o0qWgyK5O6R9i20p2gkkCT0U5pSpEuRUxnOn08B0NVc 64xjM0qiyiNqk067OBJFf5MVhkCsXjfid5RVjQ3UrroHPW+cXYHycvdypPeh848MSJ cm5lYcbjgDut9hS3dhoDxJOpXV4o+MsPn+ymRhro= From: "rsandifo at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/114635] OpenMP reductions fail dependency analysis Date: Tue, 14 May 2024 15:24:50 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: tree-optimization X-Bugzilla-Version: 14.0 X-Bugzilla-Keywords: missed-optimization, openmp X-Bugzilla-Severity: normal X-Bugzilla-Who: rsandifo at gcc dot gnu.org X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: kugan 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=3D114635 --- Comment #19 from Richard Sandiford --- (In reply to Richard Biener from comment #14) > Usually targets do have a limit on the actual length but I see > constant_upper_bound_with_limit doesn't query such. But it would > be a more appropriate way to say there might be an actual target limit he= re? The discussion has moved on, but FWIW: this was a deliberate choice. The thinking at the time was that VLA code should be truly =E2=80=9Cagnosti= c=E2=80=9D and not hard-code an upper limit. Hard-coding a limit would be hard-coding an assumption that the architectural maximum would never increase in future. (The main counterargument was that any uses of the .B form of TBL would break down for >256-byte vectors. We hardly use such TBLs for autovec though, and could easily choose not to use them at all.) That decision is 8 or 9 years old at this point, so it might seem overly dogmatic now. Even so, I think we should have a strong reason to change ta= ck. It shouldn't just be about trying to avoid poly_ints :)=