[patch] for PR17474

[Zdenek Dvorak]

Hello,

> > this handles just the cases when the base variable does not have
> > a type memory tag; in such case the variable itself acts as an
> > operand in VUSES/VDEFS (well -- I guess; it seems to work this way...)
> >
> If the base variable didn't have an alias tag already, something is
> _very_ wrong.  The base variable is dereferenced, so it must have a tag
> (either type or name).  If that's not the case, the only graceful thing
> you can do here is ICE.

then you are going to ICE very often.  For example in the following
program

int arr[100];

void xxx(void)
{
  int i;

  for (i = 0; i < 100; i++)
    arr[i] = i;
}

arr does not have type memory tag (well, did not have in time I wrote
this piece of code few months ago; perhaps this changed since then?)

Zdenek