From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 5891 invoked by alias); 3 Dec 2014 10:06:34 -0000 Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org Received: (qmail 5855 invoked by uid 48); 3 Dec 2014 10:06:30 -0000 From: "rguenth at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/64164] [4.9/5 Regression] one more stack slot used due to one less inlining level Date: Wed, 03 Dec 2014 10:06:00 -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: 5.0 X-Bugzilla-Keywords: missed-optimization X-Bugzilla-Severity: normal X-Bugzilla-Who: rguenth at gcc dot gnu.org X-Bugzilla-Status: NEW X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: 4.9.3 X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2014-12/txt/msg00327.txt.bz2 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164 --- Comment #4 from Richard Biener --- That is, it is good # _30 = PHI <0(2), _10(8), value_33(7), value_33(3), value_33(6)> return _30; vs bad # _30 = PHI <0(2), _10(8), _33(7), _33(3), _33(6)> return _30; where it thinks that coalescing _30 and _33 is more important than coalescing _30 and _10 (which looks reasonable). The question is why RTL opts make such large difference out of this.