On Fri, 2023-07-07 at 08:15 +0200, Richard Biener wrote:
/* snip */
> > + bool sign_ext = (!TYPE_UNSIGNED (TREE_TYPE (bf_ref)) &&
> > + TYPE_PRECISION (ret_type) > mask_width);
> > + bool widening = ((TYPE_PRECISION (TREE_TYPE (container)) <
> > + TYPE_PRECISION (ret_type))
> > + && !useless_type_conversion_p (TREE_TYPE (container),
> > + ret_type));
>
> the !useless_type_conversion_p check isn't necessary, when TYPE_PRECISION
> isn't equal the conversion is never useless.
I'll drop it.
> I'll also note that ret_type == TREE_TYPE (bf_ref).
No, ret_type == TREE_TYPE (ret), not TREE_TYPE (bf_ref). For something
like
struct Item
{
int x : 30;
int y : 30;
};
Item *p = get();
unsigned long t = p->y;
Then TREE_TYPE (ret) is unsigned long, and TREE_TYPE (bf_ref) is int.
In this case we still need to perform the sign extension: if p->y is -1
we should have -1ul in t. So we need to check the signedness of
TREE_TYPE (bf_ref).
> Can you rename 'widening' to 'load_widen' and 'sign_ext' to 'ref_sext'? As
> they
> are named it suggest they apply to the same so I originally thought sign_ext
> should be widening && !TYPE_UNSIGNED.
I'll rename them.
I'll send a v2 after testing it.
>
--
Xi Ruoyao <xry...@xry111.site>
School of Aerospace Science and Technology, Xidian University
