From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 29806 invoked by alias); 17 Mar 2004 08:03:44 -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 29786 invoked by uid 48); 17 Mar 2004 08:03:42 -0000 Date: Wed, 17 Mar 2004 08:03:00 -0000 Message-ID: <20040317080342.29785.qmail@sources.redhat.com> From: "kazu at cs dot umass dot edu" To: gcc-bugs@gcc.gnu.org In-Reply-To: <20020506130600.6585.bruno@clisp.org> References: <20020506130600.6585.bruno@clisp.org> Reply-To: gcc-bugzilla@gcc.gnu.org Subject: [Bug optimization/6585] Redundant store/load instruction pairs on ix86 X-Bugzilla-Reason: CC X-SW-Source: 2004-03/txt/msg02071.txt.bz2 List-Id: ------- Additional Comments From kazu at cs dot umass dot edu 2004-03-17 08:03 ------- With -O3 -fnew-ra -march=i686 -mtune=i686 -fomit-frame-pointer, I get: mul: subl $20, %esp movl %esi, 12(%esp) ; save %esi movl 24(%esp), %eax movl 32(%esp), %esi movl 28(%esp), %ecx movl %edi, 16(%esp) ; save %edi movl 36(%esp), %edi movl %eax, (%esp) mull %esi movl %ecx, 4(%esp) movl %ebx, 8(%esp) movl %eax, %ecx movl (%esp), %eax imull %eax, %edi movl 4(%esp), %eax imull %esi, %eax movl 12(%esp), %esi ; restore %esi leal (%edx,%edi), %edi leal (%edi,%eax), %ebx movl 16(%esp), %edi ; restore %edi movl %ecx, %eax movl %ebx, %edx movl 8(%esp), %ebx ; restore %ebx addl $20, %esp ret Note that those "why not" instructions are gone. "USELESS" instructions are gone even without -fnew-ra as of today's mainline. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=6585