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From: "felix dot nawothnig at t-online dot de" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/18842] Weak optimization on global references Date: Sun, 05 Dec 2004 19:11:00 -0000 [thread overview] Message-ID: <20041205191059.20812.qmail@sourceware.org> (raw) In-Reply-To: <20041205085537.18842.felix.nawothnig@t-online.de> ------- Additional Comments From felix dot nawothnig at t-online dot de 2004-12-05 19:10 ------- Diagnostics? Both files are 100% valid C++ - but since the C++ standard doesn't enforce implementation of references as pointers they cause ABI-defined (?) behaviour at/after linkage, just as... extern int x; void main() { foo(); assert(x == 5); } --- float x; void foo() { x = 5; } ...isn't guaranteed to "work" either. (but is still valid C) Reading the reference over a pointer would still work because we can't remove the reference itself from the object since someone might do "extern int &y;" in another file - but it's evil. (non-portable) *And* they are guaranteed to be const by the standard. So, yes, safe to optimize. I think. :) -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18842
next prev parent reply other threads:[~2004-12-05 19:11 UTC|newest] Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top 2004-12-05 8:55 [Bug c++/18842] New: " felix dot nawothnig at t-online dot de 2004-12-05 8:58 ` [Bug c++/18842] " felix dot nawothnig at t-online dot de 2004-12-05 14:53 ` steven at gcc dot gnu dot org 2004-12-05 15:00 ` pinskia at gcc dot gnu dot org 2004-12-05 15:14 ` [Bug tree-optimization/18842] " pinskia at gcc dot gnu dot org 2004-12-05 19:11 ` felix dot nawothnig at t-online dot de [this message] 2004-12-05 19:15 ` pinskia at gcc dot gnu dot org [not found] <bug-18842-9734@http.gcc.gnu.org/bugzilla/> 2006-03-05 21:30 ` pinskia at gcc dot gnu dot org 2006-07-16 14:23 ` felix dot nawothnig at t-online dot de 2006-07-16 20:36 ` rguenth at gcc dot gnu dot org 2009-04-22 22:02 ` pinskia at gcc dot gnu dot org
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