From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 25025 invoked by alias); 23 Apr 2012 20:03:23 -0000 Received: (qmail 25016 invoked by uid 22791); 23 Apr 2012 20:03:22 -0000 X-SWARE-Spam-Status: No, hits=-4.3 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00,KHOP_THREADED 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; Mon, 23 Apr 2012 20:03:10 +0000 From: "joseph at codesourcery dot com" To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/52907] Underflowing floating point expressions wrongly folded to zero Date: Mon, 23 Apr 2012 20:03:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: tree-optimization X-Bugzilla-Keywords: wrong-code X-Bugzilla-Severity: normal X-Bugzilla-Who: joseph at codesourcery dot com X-Bugzilla-Status: NEW 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 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: 2012-04/txt/msg02010.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52907 --- Comment #2 from joseph at codesourcery dot com 2012-04-23 20:02:50 UTC --- On Tue, 10 Apr 2012, rguenth at gcc dot gnu.org wrote: > Does real.c even communicate this fact? You can identify underflow from the result of multiplication or division being zero or subnormal (unless an operand is zero or infinite), just as overflow is identified from an infinite result. Information about subnormal results may not be conveniently communicated by real.c, but simply handling zero results here would be enough for the use cases in glibc.