From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 9865 invoked by alias); 1 Aug 2008 13:27:07 -0000 Received: (qmail 7949 invoked by uid 48); 1 Aug 2008 13:25:42 -0000 Date: Fri, 01 Aug 2008 13:27:00 -0000 Message-ID: <20080801132542.7948.qmail@sourceware.org> X-Bugzilla-Reason: CC References: Subject: [Bug target/36992] Very stange code for _mm_move_epi64 In-Reply-To: Reply-To: gcc-bugzilla@gcc.gnu.org To: gcc-bugs@gcc.gnu.org From: "hjl dot tools at gmail dot com" 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: 2008-08/txt/msg00042.txt.bz2 ------- Comment #7 from hjl dot tools at gmail dot com 2008-08-01 13:25 ------- (In reply to comment #6) > with -march=core2 it uses > > movd %xmm0, %rax > movq %rax, %xmm0 > Even this isn't necessary. We should just use movq %xmm0,%xmm0 > with -march=opteron (and -march=generic) it uses > > movhps .LC0(%rip), %xmm0 > > ISTR there is some penalty for using movq on opteron? Opteron doesn't like inter-unit move, like movd %xmm0, %rax But it isn't necessary at all. We should use movq %xmm0,%xmm0 anyway. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36992