From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id D2F603858438; Mon, 3 Oct 2022 17:37:29 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org D2F603858438 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1664818649; bh=03PfyTxYTcVRBoV00AgiNCG86POFyDJ2xFPSoraBuxg=; h=From:To:Subject:Date:In-Reply-To:References:From; b=VJtO8BXkxegcQyGZyB0vCi4uWO/2JWEgKNQW3lEpdyb5VwzRelbTsU7a0PfUyXJYM 37wOZcrJVmqugfdycuw4EcWf+KH40t3PUJq9trYBbH/4Bc64UPGbEILatBjWU8nySd ZErHAVsZHF77V9U42TMHzyo+vickIKVtgRaTm5To= From: "law at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/107114] [13 Regression] Failure to discover range results in bogus warning Date: Mon, 03 Oct 2022 17:37:29 +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: 13.0 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: law at gcc dot gnu.org X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Resolution: X-Bugzilla-Priority: P4 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=3D107114 --- Comment #2 from Jeffrey A. Law --- Which is just uber-weird. The change in question removes a little subloop which becomes unreachable. Why that would cause us to be unable to analyze= the remaining key loop for the IV's range is a complete mystery. Though I guess I'll have to sit down and debug that a bit. VRP is just calling into the l= oop optimizer to to the IV analysis, right? WRT the new blocks -- I strongly suspect they're part of normalization of t= he loop and putting it into LCSSA form. I'm not terribly worried about them.= =20 Typically they're just going to be creating empty loop latches.=