http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53382
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-05-16 23:12:02 UTC --- Basically C does not specify which order of the two operands of + are evaluated first so both clang and GCC are correct. >Since the + associativity is left-to-right Kinda but the order of evaluation is different from associativity.