From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 4243 invoked by alias); 5 Jan 2008 17:08:37 -0000 Received: (qmail 4135 invoked by alias); 5 Jan 2008 17:07:54 -0000 Date: Sat, 05 Jan 2008 21:00:00 -0000 Message-ID: <20080105170754.4134.qmail@sourceware.org> X-Bugzilla-Reason: CC References: Subject: [Bug middle-end/34678] Optimization generates incorrect code with -frounding-math option (#pragma STDC FENV_ACCESS not implemented) In-Reply-To: Reply-To: gcc-bugzilla@gcc.gnu.org To: gcc-bugs@gcc.gnu.org From: "joseph at codesourcery 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: 2008-01/txt/msg00450.txt.bz2 ------- Comment #3 from joseph at codesourcery dot com 2008-01-05 17:07 ------- Subject: Re: Optimization generates incorrect code with -frounding-math option (#pragma STDC FENV_ACCESS not implemented) On Sat, 5 Jan 2008, rguenth at gcc dot gnu dot org wrote: > Sorry, -frounding-math does not help for this case - it assumes the _same_ > rounding mode is in effect everywhere, but doesn't assume it is > round-to-nearest. To be clear: this is a bug in the present implementation of -frounding-math - it *should* disable all the assumptions of same rounding mode (unless it can prove that no function changing the rounding mode is called between the two places where it assumes the same mode), but, as documented in the manual, it's not yet fully implemented. # This option is experimental and does not currently guarantee to # disable all GCC optimizations that are affected by rounding mode. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34678