From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 10787 invoked by alias); 1 Aug 2005 18:46:54 -0000 Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org Received: (qmail 10640 invoked by uid 48); 1 Aug 2005 18:46:45 -0000 Date: Mon, 01 Aug 2005 18:46:00 -0000 Message-ID: <20050801184645.10639.qmail@sourceware.org> From: "dalej at gcc dot gnu dot org" To: gcc-bugs@gcc.gnu.org In-Reply-To: <20050112133406.19398.uros@kss-loka.si> References: <20050112133406.19398.uros@kss-loka.si> Reply-To: gcc-bugzilla@gcc.gnu.org Subject: [Bug rtl-optimization/19398] secondary reloads don't consider "m" alternatives X-Bugzilla-Reason: CC X-SW-Source: 2005-08/txt/msg00105.txt.bz2 List-Id: ------- Additional Comments From dalej at gcc dot gnu dot org 2005-08-01 18:46 ------- This is very close to the problem I ran into reported here: http://gcc.gnu.org/ml/gcc/2005-07/msg01084.html That one is fixed by the combination of the patch in PR 19653 and the patch here: http://gcc.gnu.org/ml/gcc/2005-07/msg01123.html However that is insufficient to fix this case. The difficulty is that regmove causes the same pseudo to be used for the operands and the result of the multiply. Consider that reg as all one, ST(0) is the best place for it, and you get the extra move. If you turn off regmove, the patches above fix this problem. Maybe we should do that? It seems like the register allocator should be doing what regmove is trying to do. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19398