From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 7484 invoked by alias); 8 Apr 2014 13:09:53 -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 7441 invoked by uid 48); 8 Apr 2014 13:09:50 -0000 From: "matthijs at stdin dot nl" To: gcc-bugs@gcc.gnu.org Subject: [Bug target/60300] [avr] Suboptimal stack pointer manipulation for frame setup Date: Tue, 08 Apr 2014 13:09:00 -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: 4.8.2 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: matthijs at stdin dot nl X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Priority: P3 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: 7bit X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2014-04/txt/msg00551.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60300 --- Comment #3 from Matthijs Kooijman --- Hmm, I don't think the gcc sources support that. AFAICT, they attempt to just find the shortest approach, without caring for speed. For example, look at avr.c, around line 1265, where it says: /************ Use shortest method ************/ emit_insn (get_sequence_length (sp_plus_insns) < get_sequence_length (fp_plus_insns) ? sp_plus_insns : fp_plus_insns); https://github.com/mirrors/gcc/blob/c2e306f5efb32b7eed856a1844487cff09aa86ac/gcc/config/avr/avr.c#L1265-L1270