[Bug target/27234] no way to stop gcc from mucking with the incoming argument stack on ia32

["jakub at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #18 from jakub at gcc dot gnu dot org  2008-04-11 10:25 -------
Seems I forgot to provide the testcase I was talking about.  Here it is:

__attribute__((preserve_stack)) void f1 (int a, int b, int c, int d, int e)
{
  int i;
  for (i = 0; i < 50; i++)
    {
      // Simulate high register pressure, I'm lazy
      asm volatile ("" : : "r" (e) : "%eax", "%ebx", "%ecx", "%edx", "%esi");
      e++;
      asm volatile ("" : : "r" (d) : "%eax", "%ebx", "%ecx", "%edx", "%esi");
    }
}

__attribute__((preserve_stack)) void f2 (int a, int b, int c, int d, int e)
{
  int i;
  for (i = 0; i < 50; i++)
    {
      asm volatile ("" : : "m" (e) : "%eax", "%ebx", "%ecx", "%edx", "%esi",
"%edi");
      e++;
    }
}

extern int fn (int, int);

__attribute__((preserve_stack)) int f3 (int a, int b)
{
  return fn (b, a);
}

__attribute__((preserve_stack)) int f4 (int a, int b)
{
  return fn (a, b);
}


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27234