id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
8711	cpp_int fails to construct correctly from minimum negative	Jan Bouwer <JBouwer@…>	John Maddock	"A cpp_int fails to construct correctly with the minimum negative value of a (platform dependent?) signed integral type.

Example:
{{{
template<typename T, class I>
void test_boost_multiprecision()
{
    T negMin = std::numeric_limits<T>::min();
    I test1(negMin), test2( negMin + 1 );
    --test2;
    
    assert( test1 == test2 ); // This fails on my platform for T = long
    assert( test1 != 0 );
    assert( test1 == negMin );
    assert( test2 != 0 );
    assert( test2 == negMin ); // This fails on my platform for T = long
}

test_boost_multiprecision<int64_t, boost::multiprecision::checked_cpp_int>(); // Fails on my platform

// The following hold for my platform: x86_64-apple-darwin12.4.0,
// using: Apple LLVM version 4.2 (clang-425.0.28) (based on LLVM 3.2svn)
// with: -std=c++11 -stdlib=libc++
// static_assert(std::numeric_limits<long long>::min() == std::numeric_limits<int64_t>::min(), ""Ok"");
// static_assert(std::numeric_limits<long>::min() == std::numeric_limits<int64_t>::min(), ""Ok"");
}}}"	Bugs	closed	Boost 1.55.0	multiprecision	Boost 1.53.0	Problem	fixed	cpp_int negative minimum