[Bug c/26923] New: byte swap incorrect

["behloul dot younes at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

A peace of my code uses the two next macros (SWAP and InvSwap) to swap bytes,
it worked for a long time under gcc-3.3 but not under gcc-4.0.3

under gcc-3.3:
InvWord(0xABCD) = 0xCDAB

under gcc-4-0.3:
InvWord(0xABCD) = 0xCD00   !!!!


############ FILE STARTS HERE  ##################
#define SWAP(x,y)  (x)^=(y)^=(x)^=(y)
#define InvWord(x) SWAP(*((char *)(&(x))),*((char *)(&(x))+1))
int main()
{
unsigned short data_length;
data_length = 0xABCD;
InvWord(data_length);
return 0;
}


############ FILE ENDS HERE  ###################
I've also tried to use __bswap_16 but id did nothing :(

thanks in advance


-- 
           Summary: byte swap incorrect
           Product: gcc
           Version: 4.0.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: behloul dot younes at gmail dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26923