Performace problems with gcc 3.0.4

[Paulo Pinto]

Hi,

I am sending this on behalf of a friend that
doesn't have access to the mailing list.

According to him, the following code is about
50% slower than the version without structs.

He was tried the ICC (Intel compiler) and it
generates the same code for the two cases but
gcc does not. He played with all optimization
flags that affect numeric code but to no avail.

Does anyone know what might be the problem ?

Thanks in advance,
Paulo Pinto

/* Code with structs */
#include <stdio.h>
int main() 
{
  typedef struct {
    double a;
    double b;
  } twodoubles;

  twodoubles x;
  int i;

  x.a = 0.0;
  x.b = 0.0;
  for (i = 0; i < 100000000; i++) {
    x.a = x.b + 1.0;
    x.b = x.a - x.b + 1.0;
  }

  printf("a: %g\nb: %g\n", x.a, x.b);
  return 0;
}

-------------------------------------------------------
/* Code without structs */
#include <stdio.h>

int main() 
{
  double a, b;
  int i;

  a = 0.0;
  b = 0.0;
  for (i = 0; i < 100000000; i++) {
    a = b + 1.0;
    b = a - b + 1.0;
  }

   printf("a: %g\nb: %g\n", a, b);
   return 0;
}