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From: "rguenther at suse dot de" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug fortran/41227] COMMON block, BIND(C) and LTO interoperability issues Date: Mon, 14 Jul 2014 11:46:00 -0000 [thread overview] Message-ID: <bug-41227-4-1BL39T57i2@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-41227-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=41227 --- Comment #19 from rguenther at suse dot de <rguenther at suse dot de> --- On Mon, 14 Jul 2014, burnus at gcc dot gnu.org wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=41227 > > --- Comment #17 from Tobias Burnus <burnus at gcc dot gnu.org> --- > (In reply to Francois-Xavier Coudert from comment #12) > > I disagree with Tobias' reading: it seems to me that the single-variable > > common block should be interoperable with both the single-common C struct > > and C variable. > > Well, Bill Long of Cray seems to agree with my interpretation, cf. > http://mailman.j3-fortran.org/pipermail/j3/2010-February/003358.html But that answer suggests we get it wrong (currenty interoperating with the C struct { int i; } works and with the plain decl it doesn't). The answer specifically doesn't say that only (1) is valid. > > The Intel compiler makes both cases work: > > Well, it also works with gfortran - the question is only whether it works by > chance or by purpose. If it works by chance and is invalid LTO is not required > to support it. Currently it works "by chance" because without LTO the compiler doesn't see both sides. With LTO it notices there is an inconsistency that with a clever testcase will result in wrong code (make a fortran subroutine that assigns sth to the variable, call it from the C main after its assignment of 42, read the var again in main and see it optimized to '42' in case the fortran function call is inlined)
next prev parent reply other threads:[~2014-07-14 11:46 UTC|newest] Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <bug-41227-4@http.gcc.gnu.org/bugzilla/> 2012-01-05 13:38 ` rguenth at gcc dot gnu.org 2014-06-08 16:53 ` fxcoudert at gcc dot gnu.org 2014-06-10 13:06 ` rguenth at gcc dot gnu.org 2014-07-14 10:21 ` fxcoudert at gcc dot gnu.org 2014-07-14 10:36 ` rguenther at suse dot de 2014-07-14 10:45 ` fxcoudert at gcc dot gnu.org 2014-07-14 11:09 ` rguenth at gcc dot gnu.org 2014-07-14 11:20 ` fxcoudert at gcc dot gnu.org 2014-07-14 11:36 ` burnus at gcc dot gnu.org 2014-07-14 11:46 ` rguenther at suse dot de [this message] 2014-07-14 12:05 ` tobi at gcc dot gnu.org 2014-07-14 13:33 ` burnus at gcc dot gnu.org 2015-05-27 23:55 ` hubicka at gcc dot gnu.org 2009-09-02 14:26 [Bug fortran/41227] New: " burnus at gcc dot gnu dot org 2009-09-14 21:05 ` [Bug fortran/41227] " burnus at gcc dot gnu dot org 2009-09-28 19:59 ` tobi at gcc dot gnu dot org 2010-01-29 17:46 ` burnus at gcc dot gnu dot org 2010-02-02 10:29 ` burnus at gcc dot gnu dot org 2010-02-11 16:29 ` burnus at gcc dot gnu dot org 2010-02-23 9:08 ` burnus at gcc dot gnu dot org 2010-02-23 9:33 ` rguenther at suse dot de 2010-06-03 13:49 ` rguenth at gcc dot gnu dot org
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