gcc versus g++ optimization of identical C code

[Jules Colding]

Hi,

I've observed that my little side project: 

https://github.com/colding/disruptorC


consistently performs approximately 10% better when compiled with g++ instead of gcc. Just adding "CC=g++" to configure.ac just after AC_PROG_CXX is all it takes. 

Do I do something subtly wrong or is g++ merely much better at generating code then gcc? 

Thanks,
  jules