Re: bug in check for stack growth direction in _AC_LIBOBJ_ALLOCA

[Paul Eggert]

On 06/19/11 12:01, Andy Wingo wrote:
> No, this program also exhibits the same incorrect behavior, for purposes
> of stack growth checking.

Thanks, I guess we'll have to turn it up a notch.  How about the
following test program?

int
find_stack_direction (int *addr, int depth)
{
  int dir, dummy = 0;
  if (! addr)
    addr = &dummy;
  *addr = addr < &dummy ? 1 : addr == &dummy ? 0 : -1;
  dir = depth ? find_stack_direction (addr, depth - 1) : 0;
  return dir + dummy;
}

int
main (int argc, char **argv)
{
  return find_stack_direction (0, argc + !argv + 20) < 0;
}


This program is reflected in my most recent patch, here:

http://git.savannah.gnu.org/cgit/autoconf.git/commit/?id=6cd9f12520b0d6f76d3230d7565feba1ecf29497