From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 3264 invoked by alias); 14 Jan 2014 14:58:09 -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 Received: (qmail 3219 invoked by uid 48); 14 Jan 2014 14:58:04 -0000 From: "vincent-gcc at vinc17 dot net" To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/34678] Optimization generates incorrect code with -frounding-math option (#pragma STDC FENV_ACCESS not implemented) Date: Tue, 14 Jan 2014 14:58:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: middle-end X-Bugzilla-Version: 4.3.0 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: vincent-gcc at vinc17 dot net X-Bugzilla-Status: NEW X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2014-01/txt/msg01470.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D34678 --- Comment #26 from Vincent Lef=C3=A8vre -= -- (In reply to Nick Maclaren from comment #25) > 3.4.3 says: > undefined behavior > behavior, upon use of a nonportable or erroneous program construct > or of erroneous data, for which this International Standard imposes > no requirements >=20 > 4. Conformance, paragraph 2, says: > ... Undefined behavior is otherwise indicated in this International > Standard by the words "undefined behavior" or by the omission of any > explicit definition of behavior. There is no difference in emphasis > among these three; they all describe "behavior that is undefined". >=20 > What "explicit definition of behavior" is there for the case when > STDC FENV_ACCESS is set to "on" but __STDC_IEC_559__ is not set to one? The behavior is defined. The standard says, e.g. for C99: ---- 7.6.1 The FENV_ACCESS pragma The FENV_ACCESS pragma provides a means to inform the implementation when a program might access the floating-point environment to test floating-point status flags or run under non-default floating-point control modes.184) [..= .] 184) The purpose of the FENV_ACCESS pragma is to allow certain optimizations that could subvert flag tests and mode changes (e.g., global common ubexpression elimination, code motion, and constant folding). In general, if the state of FENV_ACCESS is ``off'', the translator can assume that default modes are in effect and the flags are not tested. ---- And there is here no relation at all with __STDC_IEC_559__. > As there is none, it is undefined behaviour. gcc can therefore do > whatever it likes. No. >>From gcc-bugs-return-440329-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Tue Jan 14 15:06:52 2014 Return-Path: Delivered-To: listarch-gcc-bugs@gcc.gnu.org Received: (qmail 7702 invoked by alias); 14 Jan 2014 15:06:52 -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 Delivered-To: mailing list gcc-bugs@gcc.gnu.org Received: (qmail 7582 invoked by uid 48); 14 Jan 2014 15:06:43 -0000 From: "ktkachov at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug target/59787] [ARM] mmx-2.c causes ICE when GCC is configured for cortex-a5/vfpv3-d16-fp16 Date: Tue, 14 Jan 2014 15:06:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: target X-Bugzilla-Version: 4.9.0 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: ktkachov at gcc dot gnu.org X-Bugzilla-Status: NEW X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_status cf_reconfirmed_on cc everconfirmed Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2014-01/txt/msg01471.txt.bz2 Content-length: 647 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59787 ktkachov at gcc dot gnu.org changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Last reconfirmed| |2014-01-14 CC| |ktkachov at gcc dot gnu.org, | |vmakarov at redhat dot com Ever confirmed|0 |1 --- Comment #2 from ktkachov at gcc dot gnu.org --- Adding Vlad to cc, since this seems to be an LRA ICE.