The program below on gcc 4.1.2 prints:

> gcc4 test.c
> ./a.out
got 0
x
y
done

----------------------------------
The program below on gcc 3.4.4 prints:

> gcc test.c
> ./a.out
got 0
x
y

and then locks up...

----------------------------------

#include <stdio.h>

int main()
{
  unsigned int var102 = 1;
  int a = ( var102 >> 0x1eU & sizeof 290 );
  printf("got %d\n", a); fflush(stdout);

  for ( ; 0; )
  {}
  printf("x\n"); fflush(stdout);
  
  for ( ; a; )
  {}
  printf("y\n"); fflush(stdout);
  
  for ( ; ( var102 >> 0x1eU & sizeof 290 ); ) // Fails here
  {}
  printf("done\n");
  
  return 0;
}