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From: "gael.guennebaud at gmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/53900] [regression] Too optimistic on a alignment assert Date: Tue, 10 Jul 2012 11:09:00 -0000 [thread overview] Message-ID: <bug-53900-4-8OrXLeas0U@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-53900-4@http.gcc.gnu.org/bugzilla/> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53900 --- Comment #4 from Gael Guennebaud <gael.guennebaud at gmail dot com> 2012-07-10 11:09:16 UTC --- Created attachment 27770 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27770 Another demonstration of the issue using std::vector Note that when we declare: __attribute__((aligned(16))) float array[4]; we request GCC to give us an aligned array, and we are not telling gcc that array is aligned that is slightly different. I attached another example demonstrating the problem: a simple declaration like: std::vector<Foo> vec(5); generates unaligned arrays that are not caught by assertion because it has been removed by gcc 4.7. Outputs are as follow: $ g++-4.7 -m32 alignedassert.cpp && ./a.out ctor 0xffdc58f0 copy 0x9f72008 copy 0x9f72018 copy 0x9f72028 copy 0x9f72038 copy 0x9f72048 ctor 0xffdc5900 g++-4.6 -m32 alignedassert.cpp && ./a.out ctor 0xff8e19e0 copy 0x98e2008 a.out: alignedassert.cpp:18: Foo::Foo(const Foo&): Assertion `(std::ptrdiff_t(array) % std::ptrdiff_t(16))==0' failed. Aborted
next prev parent reply other threads:[~2012-07-10 11:09 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-07-09 14:57 [Bug c++/53900] New: " gael.guennebaud at gmail dot com 2012-07-09 15:23 ` [Bug c++/53900] [regression] " rguenth at gcc dot gnu.org 2012-07-09 16:12 ` gael.guennebaud at gmail dot com 2012-07-09 16:19 ` rguenth at gcc dot gnu.org 2012-07-10 11:09 ` gael.guennebaud at gmail dot com [this message] 2012-12-28 17:47 ` xarthisius.kk at gmail dot com 2013-01-07 4:27 ` pinskia at gcc dot gnu.org 2013-01-07 10:19 ` chtz at informatik dot uni-bremen.de 2013-01-07 10:22 ` pinskia at gcc dot gnu.org 2015-02-19 15:27 ` jacob.benoit.1 at gmail dot com
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