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Re: [tree-ssa]: Dominator opts change LHS without changing VDEF's


On Sun, 2003-08-10 at 17:17, Daniel Berlin wrote:

> > > This causes the vdef's to changes, because the memory tag for elt isn't
> > > the same as elt.
> > >
> > They aren't?
> No.
>
But, why?  This only occurs with PTA, why aren't those variables
considered aliased?  They do seem aliased to me.  If they are aliased,
they will get the same memory tag.  In this case they don't get the same
memory tag because alias analysis tells us that they aren't aliased, I
want to know why alias analysis doesn't consider them aliased.

The very fact that we can copy propagate one into the other means that
they are aliased.  If alias analysis is saying that they can't alias,
then alias analysis is wrong.


bitmap_element_free (struct bitmap_element *elt)
{
....
  {
     struct bitmap_element * elt;
     struct bitmap_head_def * head;

     head = head;
     elt = elt;			<-- Here 'elt' points to 'elt'.
  }
}



Diego.


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