Using boost::atomic for 128-bit type results in build error with GCC 4.4

[Martin Srom <srom.martin@…>]

When using boost::atomic with 128-bit type it results into a build error with GCC 4.4.

With GCC 4.6 it works fine. With 64-bit type it works fine.

Minimal example:

main.cpp:

#include <boost/atomic.hpp>

int main()
{
    boost::atomic<__int128_t> variable(0);
    variable.load();   
} 

Build command:

g++-4.4 -O3 -mcx16 main.cpp -Iboost_1_57_0/

Error output:

boost_1_57_0/boost/atomic/detail/ops_gcc_x86_dcas.hpp: In function ‘int main()’:
boost_1_57_0/boost/atomic/detail/ops_gcc_x86_dcas.hpp:261: error: impossible constraint in ‘asm’

[Andrey Semashev]

Fixed in ​https://github.com/boostorg/atomic/commit/ff91811c1a2f87748fb36cecfe9da1dc7a596bce.