gcc/testsuite/gcc.dg/pr9771-1.c

   1 /* PR rtl-optimization/9771 */
   2 /* { dg-do run { target i?86-*-* } } */
   3 /* { dg-options "-O2 -fomit-frame-pointer -ffixed-ebp" } */
   4
   5 extern void abort(void);
   6 extern void exit(int);
   7
   8 register long *B asm ("ebp");
   9
  10 long x = 10;
  11 long y = 20;
  12
  13 void bar(void)
  14 {
  15   B = &y;
  16 }
  17
  18 void foo()
  19 {
  20   long *adr = B;
  21   long save = *adr;
  22
  23   *adr = 123;
  24
  25   bar();
  26
  27   *adr = save;
  28 }
  29
  30 int main()
  31 {
  32   B = &x;
  33
  34   foo();
  35
  36   if (x != 10 || y != 20)
  37     abort();
  38
  39   /* We can't return, as our caller may assume %ebp is preserved!  */
  40   /* We could save/restore it (like foo), but its easier to exit.  */
  41   exit(0);
  42 }
  43