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

   1 /* PR rtl-optimization/9771 */
   2 /* { dg-do run { target i?86-*-* x86_64-*-* } } */
   3 /* { dg-require-effective-target ilp32 } */
   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 int main()
  32 {
  33   B = &x;
  34
  35   foo();
  36
  37   if (x != 10 || y != 20)
  38     abort();
  39
  40   /* We can't return, as our caller may assume %ebp is preserved!  */
  41   /* We could save/restore it (like foo), but its easier to exit.  */
  42   exit(0);
  43 }
  44