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From: Peter Dimov (pdimov_at_[hidden])
Date: 2005-05-11 16:14:14

Apparently, g++ 4.0.0 with -O3 manages to optimize out one of the shared_ptr
instances in the example below:

#include <boost/shared_ptr.hpp>
#include <boost/detail/lightweight_test.hpp>

int main()
    boost::shared_ptr<int> pi(new int);
    boost::shared_ptr<void> pv(pi);

    boost::shared_ptr<int> pi2 = boost::static_pointer_cast<int>(pv);

    BOOST_TEST(pi.get() == pi2.get());
    BOOST_TEST(!(pi < pi2 || pi2 < pi));
    BOOST_TEST(pi.use_count() == 3);
    BOOST_TEST(pv.use_count() == 3);
    BOOST_TEST(pi2.use_count() == 3);

    return boost::report_errors();

and the use_count() tests fail.

-O0, 1, 2 are fine, and replacing BOOST_TEST with assert is fine, too.
Printing the use_count() also gives 3, as expected. Must be an interesting
optimizer bug (or feature.)

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