1  /* PR rtl-optimization/9771 */
       2  /* { dg-do run } */
       3  /* { dg-require-effective-target ia32 } */
       4  /* { dg-options "-O2 -fomit-frame-pointer -ffixed-ebp" } */
       5  
       6  extern void abort(void);
       7  extern void exit(int);
       8  
       9  register long *B asm ("ebp");
      10  
      11  long x = 10;
      12  long y = 20;
      13  
      14  void bar(void)
      15  {
      16    B = &y;
      17  }
      18  
      19  void foo()
      20  {
      21    long *adr = B;
      22    long save = *adr;
      23  
      24    *adr = 123;
      25  
      26    bar();
      27  
      28    *adr = save;
      29  }
      30  
      31  /* This must not be inlined because main() requires the frame pointer
      32     for stack alignment.  */
      33  void test(void) __attribute__((noinline));
      34  void test(void)
      35  {
      36    B = &x;
      37  
      38    foo();
      39  
      40    if (x != 10 || y != 20)
      41      abort();
      42  
      43    /* We can't return, as our caller may assume %ebp is preserved!  */
      44    /* We could save/restore it (like foo), but its easier to exit.  */
      45    exit(0);
      46  }
      47  
      48  /* main usually performs dynamic realignment of the stack in case
      49     _start would fail to properly align the stack, but for dynamic
      50     stack realignment we need frame pointer which is incompatible
      51     with -ffixed-ebp and the global register var.  So, cheat here
      52     and hide from the compiler that main is really main.  */
      53  #define ASMNAME(cname)  ASMNAME2 (__USER_LABEL_PREFIX__, cname)
      54  #define ASMNAME2(prefix, cname) STRING (prefix) cname
      55  #define STRING(x)    #x
      56  int real_main() __asm (ASMNAME ("main"));
      57  
      58  int real_main()
      59  {
      60    test();
      61    return 0;
      62  
      63  }