Re: [PATCH 17/12] _BitInt a ? ~b : b match.pd fix [PR102989]

[Jakub Jelinek <jakub@redhat.com>]

On Tue, Sep 05, 2023 at 02:27:10PM -0700, Andrew Pinski wrote:
> > I admit it isn't really clear to me what do you want to achieve by the
> > above build_nonstandard_integer_type.  Is it because of BOOLEAN_TYPE
> > or perhaps ENUMERAL_TYPE as well?
> 
> Yes I was worried about types where the precision was set but MIN/MAX
> of that type was not over the full precision and would not include
> both 0 and allones in that range.
> There is another match.pd pattern where we do a similar thing with
> calling build_nonstandard_integer_type for a similar reason but
> because we don't know if the type includes 0, 1, and allones in their
> range.

Ah, in that case you should use range_check_type, that is used already
in multiple spots in match.pd for the same purpose.  It can return NULL and
in that case one should punt on the optimization.  Otherwise, that is the
function which ensures that the type is unsigned and max + 1 is min and min
- 1 is max.
And for me, I should add BITINT_TYPE handling to that function.

> > If type is INTEGER_TYPE or BITINT_TYPE, one doesn't really need to create a
> > new type, type already is an integral type with that precision and
> > signedness.  In other places using unsigned_type_for or signed_type_for
> > might be better than using build_nonstandard_integer_type if that is what
> > one wants to achieve, those functions handle BITINT_TYPE.
> 
> Maybe here we should just use `signed_or_unsigned_type_for (type,
> TYPE_SIGN (type));`
> instead of build_nonstandard_integer_type.

No, signed_or_unsigned_type_for (TYPE_UNSIGNED (type), type) will just return
type.
  if (ANY_INTEGRAL_TYPE_P (type) && TYPE_UNSIGNED (type) == unsignedp)
    return type;

	Jakub