[Bug c++/56564] New: [4.7 Regression] movdqa on possibly-8-byte-aligned struct with -O3

[lukeocamden at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56564



             Bug #: 56564

           Summary: [4.7 Regression] movdqa on possibly-8-byte-aligned

                    struct with -O3

    Classification: Unclassified

           Product: gcc

           Version: 4.7.2

            Status: UNCONFIRMED

          Severity: normal

          Priority: P3

         Component: c++

        AssignedTo: unassig...@gcc.gnu.org

        ReportedBy: lukeocam...@gmail.com





#include <boost/exception_ptr.hpp>



struct foo { };



int main()

{

  boost::copy_exception(foo());

}



Compiling the above with -O3 results in the following instruction being

emitted:



movdqa  %xmm0,

_ZZN5boost16exception_detail27get_static_exception_objectINS0_10bad_alloc_EEENS_13exception_ptrEvE2ep(%rip)



But that symbol need not be 16-byte aligned (it's a boost::exception_ptr, which

contains a boost::shared_ptr, which is just a pair of pointers).



This crashes if

_ZZN5boost16exception_detail27get_static_exception_objectINS0_10bad_alloc_EEENS_13exception_ptrEvE2ep

comes from another object file where it is declared with 8-byte alignment.



Possible duplicate of 54167? Works fine with 4.6.2



Preprocessed source is attached.