From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 13947 invoked by alias); 12 May 2011 08:49:58 -0000 Received: (qmail 13938 invoked by uid 22791); 12 May 2011 08:49:58 -0000 X-SWARE-Spam-Status: No, hits=-2.7 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from localhost (HELO gcc.gnu.org) (127.0.0.1) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 12 May 2011 08:49:11 +0000 From: "zuxy.meng at gmail dot com" To: gcc-bugs@gcc.gnu.org Subject: [Bug target/48743] -march=native mis-detects AMD K6-2+ / K6-3 as Athlon - compiled C fails with "illegal instruction" X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: target X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: zuxy.meng at gmail dot com 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 Date: Thu, 12 May 2011 08:59:00 -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 X-SW-Source: 2011-05/txt/msg00997.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48743 --- Comment #3 from Zuxy 2011-05-12 08:27:56 UTC --- Created attachment 24233 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24233 Proposed patch For a brief time AMD produced K6-2+ and K6-3+ processors, targeting mobile market. These processors support Extended 3DNow! but not CMOV or Extended MMX (a subset of SSE) and are detected as Athlon by GCC so GCC will generate CMOV for them, leading to #UD. The patch solves the problem by differentiating K6 and Athlon by Extended MMX rather than Extended 3DNow!.