[PATCH] tree-optimization/103759: Truncate unknown to sizetype on compare

[Jakub Jelinek]

On Sat, Dec 18, 2021 at 02:53:47AM +0530, Siddhesh Poyarekar wrote:
> Since all computations in tree-object-size are now done in sizetype and
> not HOST_WIDE_INT, comparisons after conversion to HOST_WIDE_INT would
> be incorrect.  Instead, truncate unknown (object_size_type) to sizetype
> to compare with the computed size to evaluate if it is unknown.
> 
> gcc/ChangeLog:
> 
> 	PR tree-optimization/103759
> 	* tree-object-size (size_unknown_p): Construct a size_unknown
> 	and compare with VAL.

I think you should instead drop initval and unknown inlines and
rewrite size_unknown, size_initval and size_unknown_p to work
directly on trees.
size_initval to
  return ((object_size_type & OST_MINIMUM)
	  ? TYPE_MAX_VALUE (sizetype) : size_zero_node);
size_unknown to
  return ((object_size_type & OST_MINIMUM)
	  ? size_zero_node : TYPE_MAX_VALUE (sizetype));
and size_unknown_p to:
  return ((object_size_type & OST_MINIMUM)
	  ? integer_zerop (val) : integer_all_onesp (val));

	Jakub