text: #include <stdio.h>
  #include <stdint.h>
  void f(uintptr_t ix) {
    int y=0;
    uintptr_t iy;
      iy = ix - 0x30;  // for O0   - prints y=1
    //iy = ix - 0x20;   // for O2   - prints y=0
    int *py = (int*)iy;
    *py=1;
    printf("&y=%p  iy=0x%lx  equal=%s  ",(void*)&y,iy,(((uintptr_t)&y)==iy)?"true":"false");
    printf("y=%d\n",y); 
  }
  int main() {
    int x=0;
    f((uintptr_t)&x); 
  }
  