Ughhh, you're right.  Thanks for spotting this.

I'm testing the attached patch and will commit if it passes tests.

Aldy

On Tue, Apr 30, 2024 at 9:46 AM Richard Biener
<richard.guenther@gmail.com> wrote:
>
> On Sun, Apr 28, 2024 at 9:07 PM Aldy Hernandez <aldyh@redhat.com> wrote:
> >
> > Fix some Value_Range's that we know ahead of time will be only
> > integers.  This avoids using the polymorphic Value_Range unnecessarily
>
> But isn't Value_Range a variable-size irange but int_range<2> doesn't
> support more than two sub-ranges?
>
> So it doesn't look obvious that this isn't actually a regression?
>
> Richard.
>
> > gcc/ChangeLog:
> >
> >         * gimple-ssa-warn-access.cc (check_nul_terminated_array): Make Value_Range an int_range.
> >         (memmodel_to_uhwi): Same
> >         * tree-ssa-loop-niter.cc (refine_value_range_using_guard): Same.
> >         (determine_value_range): Same.
> >         (infer_loop_bounds_from_signedness): Same.
> >         (scev_var_range_cant_overflow): Same.
> > ---
> >  gcc/gimple-ssa-warn-access.cc |  4 ++--
> >  gcc/tree-ssa-loop-niter.cc    | 12 ++++++------
> >  2 files changed, 8 insertions(+), 8 deletions(-)
> >
> > diff --git a/gcc/gimple-ssa-warn-access.cc b/gcc/gimple-ssa-warn-access.cc
> > index dedaae27b31..450c1caa765 100644
> > --- a/gcc/gimple-ssa-warn-access.cc
> > +++ b/gcc/gimple-ssa-warn-access.cc
> > @@ -330,7 +330,7 @@ check_nul_terminated_array (GimpleOrTree expr, tree src, tree bound)
> >    wide_int bndrng[2];
> >    if (bound)
> >      {
> > -      Value_Range r (TREE_TYPE (bound));
> > +      int_range<2> r (TREE_TYPE (bound));
> >
> >        get_range_query (cfun)->range_of_expr (r, bound);
> >
> > @@ -2816,7 +2816,7 @@ memmodel_to_uhwi (tree ord, gimple *stmt, unsigned HOST_WIDE_INT *cstval)
> >      {
> >        /* Use the range query to determine constant values in the absence
> >          of constant propagation (such as at -O0).  */
> > -      Value_Range rng (TREE_TYPE (ord));
> > +      int_range<2> rng (TREE_TYPE (ord));
> >        if (!get_range_query (cfun)->range_of_expr (rng, ord, stmt)
> >           || !rng.singleton_p (&ord))
> >         return false;
> > diff --git a/gcc/tree-ssa-loop-niter.cc b/gcc/tree-ssa-loop-niter.cc
> > index c6d010f6d89..cbc9dbc5a1f 100644
> > --- a/gcc/tree-ssa-loop-niter.cc
> > +++ b/gcc/tree-ssa-loop-niter.cc
> > @@ -214,7 +214,7 @@ refine_value_range_using_guard (tree type, tree var,
> >    get_type_static_bounds (type, mint, maxt);
> >    mpz_init (minc1);
> >    mpz_init (maxc1);
> > -  Value_Range r (TREE_TYPE (varc1));
> > +  int_range<2> r (TREE_TYPE (varc1));
> >    /* Setup range information for varc1.  */
> >    if (integer_zerop (varc1))
> >      {
> > @@ -368,7 +368,7 @@ determine_value_range (class loop *loop, tree type, tree var, mpz_t off,
> >        gphi_iterator gsi;
> >
> >        /* Either for VAR itself...  */
> > -      Value_Range var_range (TREE_TYPE (var));
> > +      int_range<2> var_range (TREE_TYPE (var));
> >        get_range_query (cfun)->range_of_expr (var_range, var);
> >        if (var_range.varying_p () || var_range.undefined_p ())
> >         rtype = VR_VARYING;
> > @@ -382,7 +382,7 @@ determine_value_range (class loop *loop, tree type, tree var, mpz_t off,
> >
> >        /* Or for PHI results in loop->header where VAR is used as
> >          PHI argument from the loop preheader edge.  */
> > -      Value_Range phi_range (TREE_TYPE (var));
> > +      int_range<2> phi_range (TREE_TYPE (var));
> >        for (gsi = gsi_start_phis (loop->header); !gsi_end_p (gsi); gsi_next (&gsi))
> >         {
> >           gphi *phi = gsi.phi ();
> > @@ -408,7 +408,7 @@ determine_value_range (class loop *loop, tree type, tree var, mpz_t off,
> >                      involved.  */
> >                   if (wi::gt_p (minv, maxv, sgn))
> >                     {
> > -                     Value_Range vr (TREE_TYPE (var));
> > +                     int_range<2> vr (TREE_TYPE (var));
> >                       get_range_query (cfun)->range_of_expr (vr, var);
> >                       if (vr.varying_p () || vr.undefined_p ())
> >                         rtype = VR_VARYING;
> > @@ -4367,7 +4367,7 @@ infer_loop_bounds_from_signedness (class loop *loop, gimple *stmt)
> >
> >    low = lower_bound_in_type (type, type);
> >    high = upper_bound_in_type (type, type);
> > -  Value_Range r (TREE_TYPE (def));
> > +  int_range<2> r (TREE_TYPE (def));
> >    get_range_query (cfun)->range_of_expr (r, def);
> >    if (!r.varying_p () && !r.undefined_p ())
> >      {
> > @@ -5426,7 +5426,7 @@ scev_var_range_cant_overflow (tree var, tree step, class loop *loop)
> >    if (!def_bb || !dominated_by_p (CDI_DOMINATORS, loop->latch, def_bb))
> >      return false;
> >
> > -  Value_Range r (TREE_TYPE (var));
> > +  int_range<2> r (TREE_TYPE (var));
> >    get_range_query (cfun)->range_of_expr (r, var);
> >    if (r.varying_p () || r.undefined_p ())
> >      return false;
> > --
> > 2.44.0
> >
>