[PATCH]: Fix pointer arithmetic handling in tree-ssa-structalias.c

[Richard Guenther]

On 12/13/06, Grigory Zagorodnev <grigory_zagorodnev@linux.intel.com> wrote:
> Daniel,
> Your patch caused cpu2006/gcc to fail (results miscompare) at -O2
> optimization level with 'test' dataset on ia32.
>
> - Grigory
>
> Daniel Berlin wrote:
> > Without this patch, we are currently considering *(p + x) and *(p + y)
> > to point to the same thing, even when x and y are not equal.
> >
> > This is due to a missing else clause.
> >
> > Fixed thusly.

I wonder what we do for MINUS_EXPR there...

  if (TREE_CODE (expr) != PLUS_EXPR
      && TREE_CODE (expr) != MINUS_EXPR)
    return false;

  op0 = TREE_OPERAND (expr, 0);
  op1 = TREE_OPERAND (expr, 1);

  get_constraint_for (op0, &temp);
  if (POINTER_TYPE_P (TREE_TYPE (op0))
      && TREE_CODE (op1) == INTEGER_CST
      && TREE_CODE (expr) == PLUS_EXPR)
    {
      rhsoffset = TREE_INT_CST_LOW (op1) * BITS_PER_UNIT;
    }
  else
    return false;

but all the stuff looks "interesting" anyway ;)  (See PR29716)

Richard.