From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 8948 invoked by alias); 3 Jan 2010 07:07:38 -0000 Received: (qmail 8904 invoked by uid 48); 3 Jan 2010 07:07:27 -0000 Date: Sun, 03 Jan 2010 07:07:00 -0000 Message-ID: <20100103070727.8903.qmail@sourceware.org> X-Bugzilla-Reason: CC References: Subject: [Bug tree-optimization/42586] New: load-modify-store on x86 should be \ single instruction In-Reply-To: Reply-To: gcc-bugzilla@gcc.gnu.org To: gcc-bugs@gcc.gnu.org From: "pinskia at gcc dot gnu dot org" 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 X-SW-Source: 2010-01/txt/msg00235.txt.bz2 ------- Comment #12 from pinskia at gcc dot gnu dot org 2010-01-03 07:07 ------- (In reply to comment #11) > My naive assumption was that the read-modify-write pattern is handled late by > the RTL backend when generating instructions while SRA is somewhere early in > the tree oriented middle end. Well the other issue is that only post-reload-cse deletes the load/stores without SRA doing what needs to be done. And since the deletion happens so late, combine does not combine the three instruction which does the read-modify-write. :). -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42586