gcc/testsuite/gcc.dg/20041106-1.c

   1 /* { dg-do run { target *-*-linux* *-*-gnu* *-*-solaris* } } */
   2 /* { dg-options -O2 } */
   3
   4 #include <sys/types.h>
   5 #include <sys/mman.h>
   6 #include <unistd.h>
   7 #include <stdlib.h>
   8
   9 struct S { long x __attribute__((packed)); }; /* { dg-warning "attribute ignored" "" { target default_packed } } */
  10 volatile long sink;
  11
  12 void foo (struct S *s)
  13 {
  14   sink = s->x;
  15 }
  16
  17 int main ()
  18 {
  19   size_t ps = getpagesize ();
  20   char *ptr, *page;
  21   struct S *s;
  22
  23   ptr = malloc (3*ps);
  24   page = (char *)(((__UINTPTR_TYPE__)ptr + (ps - 1)) & -ps);
  25   munmap (page + ps, ps);
  26
  27   s = (struct S *)(page + ps - sizeof(struct S));
  28   foo(s);
  29
  30   return 0;
  31 }