On Wed, Jan 05, 2022 at 10:38:53AM +0100, Richard Biener via Gcc-patches wrote:
> On Wed, Jan 5, 2022 at 10:18 AM Zhao Wei Liew <zhaoweil...@gmail.com> wrote:
> >
> > > X >= -1 && X <= 1 is (hopefully?) going to be simplified
> > > as (unsigned)X + 1 <= 2, it might be good to simplify it this way
> > > here as well?
> >
> > Yup, GCC does simplify it that way in the end, so I didn't really bother to
> > simplify it here. That said, I'm open to simplifying it here as well, but
> > I'm not sure how to do the unsigned cast.
>
> You'd do sth like
> (with
> { tree utype = unsigned_type_for (type); }
> (cond (le (plus (convert:utype @0) { build_one_cst (utype); }) {
> build_int_cst (utype, 2); }) ...)
>
> extra tricky will be 1 bit integer types, I guess it might be easiest
> to exclude them
> and special case them separately - X / Y is always X for them I think,
Note, we already have:
/* X / bool_range_Y is X. */
(simplify
(div @0 SSA_NAME@1)
(if (INTEGRAL_TYPE_P (type) && ssa_name_has_boolean_range (@1))
@0))
for those.
Jakub
