On Mon, Jun 20, 2022 at 10:38 AM Jakub Jelinek <ja...@redhat.com> wrote:
>
> On Mon, Jun 20, 2022 at 09:36:28AM +0200, Richard Biener wrote:
> > > --- a/gcc/match.pd
> > > +++ b/gcc/match.pd
> > > @@ -2080,6 +2080,19 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> > > (if (ANY_INTEGRAL_TYPE_P (TREE_TYPE (@0))
> > > && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (@0)))
> > > (op @0 @1))))
> > > +
> > > +/* As a special case, X + C < Y + C is the same as (signed) X < (signed)
> > > Y
> > > + when C is an unsigned integer constant with only the MSB set, and X
> > > and
> > > + Y have types of equal or lower integer conversion rank than C's. */
> > > +(for op (lt le ge gt)
> > > + (simplify
> > > + (op (plus @1 INTEGER_CST@0) (plus @2 INTEGER_CST@0))
>
> Can't one just omit the INTEGER_CST part on the second @0?
Ah, yes.
> > > + (if (INTEGRAL_TYPE_P (TREE_TYPE (@0))
> > > + && TYPE_UNSIGNED (TREE_TYPE (@0))
> > > + && wi::only_sign_bit_p (wi::to_wide (@0)))
> > > + (with { tree stype = signed_type_for (TREE_TYPE (@0)); }
> > > + (op (convert:stype @1) (convert:stype @2))))))
>
> As a follow-up, it might be useful to make it work for vector integral types
> too,
> typedef unsigned V __attribute__((vector_size (4 * sizeof (int))));
> #define M __INT_MAX__ + 1U
> V foo (V x, V y)
> {
> return x + (V) { M, M, M, M } < y + (V) { M, M, M, M };
> }
> using uniform_integer_cst_p.
>
> Jakub
>
