From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 6595 invoked by alias); 13 Apr 2013 10:32:48 -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 6565 invoked by uid 48); 13 Apr 2013 10:32:46 -0000 From: "mikael at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug fortran/56937] Unnecessarily temporary with array-vector assignments Date: Sat, 13 Apr 2013 10:32:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: fortran X-Bugzilla-Keywords: missed-optimization X-Bugzilla-Severity: normal X-Bugzilla-Who: mikael at gcc dot gnu.org X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 X-SW-Source: 2013-04/txt/msg01337.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56937 --- Comment #5 from Mikael Morin 2013-04-13 10:32:46 UTC --- (In reply to comment #0) > tmp(2) = r(1) + 0.25 ! r(1:4) == 0 > tmp(2) = r(2) + 0.25 > tmp(3) = r(3) + 0.25 > tmp(2) = r(4) + 0.25 > r(2) = tmp(2) ! = 0.25 > r(2) = tmp(2) ! = 0.25 > r(3) = tmp(3) ! = 0.25 > r(2) = tmp(2) ! = 0.25 > -> sum(r) = 0.5 > By the way, it's rather: tmp(1) = r(2) + 0.25 ! r(1:4) == 0 tmp(2) = r(2) + 0.25 tmp(3) = r(3) + 0.25 tmp(4) = r(2) + 0.25 r(2) = tmp(1) ! = 0.25 r(2) = tmp(2) ! = 0.25 r(3) = tmp(3) ! = 0.25 r(2) = tmp(4) ! = 0.25 -> sum(r) = 0.5