[solved] optimization/8302: -fno-strict-aliasing was missing

[Yaacov Akiba Slama]

Hello,

The following code aborts if "-fstrict-aliasing" is set (and this seems 
to be implied by "-O2") with gcc-3.2 (and newer versions also).
This seems to be the right behavior.
This solves the bug 8302.

// This sample crashes with -fstrict-aliasing (or -O2) but returns 0 
with -fno-strict-aliasing

unsigned char *p;


unsigned char * aux(unsigned char **pBuffer) {
  return *pBuffer + 1;
}

int
test(int a2, unsigned char a3)
{

    unsigned char *Buffer;
    unsigned char * t1;
    unsigned char * t2;

    p = Buffer = (unsigned char *) malloc(30);

    aux(&Buffer);
           
    *(*(( int * * )&Buffer))++ = a2;
       
    t1 = Buffer;

    *Buffer = a3;

    t2 = Buffer; // t2 == t1 when OK.

    return t1-t2; //0 if OK.
}

int main()
{

  int d;

  d = test(0x41414141,'a');

  if (d != 0)
     abort();
  return 0;
}