frange: drop endpoints to min/max representable numbers for -ffinite-math-only.

  Similarly to how we drop NANs to UNDEFINED when -ffinite-math-only, I
think we can drop the numbers outside of the min/max representable
numbers to the representable number.

This means the endpoings to VR_VARYING for -ffinite-math-only can now
be the min/max representable, instead of -INF and +INF.

Saturating in the setter means that the upcoming implementation for
binary operators no longer have to worry about doing the right
thing for -ffinite-math-only.  If the range goes outside the limits,
it'll get chopped down.

How does this look?

Tested on x86-64 Linux.

gcc/ChangeLog:

	* range-op-float.cc (build_le): Use vrp_val_*.
	(build_lt): Same.
	(build_ge): Same.
	(build_gt): Same.
	* value-range.cc (frange::set): Chop ranges outside of the
	representable numbers for -ffinite-math-only.
	(frange::normalize_kind): Use vrp_val*.
	(frange::verify_range): Same.
	(frange::set_nonnegative): Same.
	(range_tests_floats): Remove tests that depend on -INF and +INF.
	* value-range.h (real_max_representable): Add prototype.
	(real_min_representable): Same.
	(vrp_val_max): Set max representable number for
	-ffinite-math-only.
	(vrp_val_min): Same but for min.
	(frange::set_varying): Use vrp_val*.
---
 gcc/range-op-float.cc | 12 +++++++----
 gcc/value-range.cc    | 46 ++++++++++++++++++++-----------------------
 gcc/value-range.h     | 30 ++++++++++++++++++++++------
 3 files changed, 53 insertions(+), 35 deletions(-)
  

On Thu, Sep 22, 2022 at 6:49 PM Aldy Hernandez <aldyh@redhat.com> wrote:
>
> Similarly to how we drop NANs to UNDEFINED when -ffinite-math-only, I
> think we can drop the numbers outside of the min/max representable
> numbers to the representable number.
>
> This means the endpoings to VR_VARYING for -ffinite-math-only can now
> be the min/max representable, instead of -INF and +INF.
>
> Saturating in the setter means that the upcoming implementation for
> binary operators no longer have to worry about doing the right
> thing for -ffinite-math-only.  If the range goes outside the limits,
> it'll get chopped down.
>
> How does this look?
>
> Tested on x86-64 Linux.
>
> gcc/ChangeLog:
>
>         * range-op-float.cc (build_le): Use vrp_val_*.
>         (build_lt): Same.
>         (build_ge): Same.
>         (build_gt): Same.
>         * value-range.cc (frange::set): Chop ranges outside of the
>         representable numbers for -ffinite-math-only.
>         (frange::normalize_kind): Use vrp_val*.
>         (frange::verify_range): Same.
>         (frange::set_nonnegative): Same.
>         (range_tests_floats): Remove tests that depend on -INF and +INF.
>         * value-range.h (real_max_representable): Add prototype.
>         (real_min_representable): Same.
>         (vrp_val_max): Set max representable number for
>         -ffinite-math-only.
>         (vrp_val_min): Same but for min.
>         (frange::set_varying): Use vrp_val*.
> ---
>  gcc/range-op-float.cc | 12 +++++++----
>  gcc/value-range.cc    | 46 ++++++++++++++++++++-----------------------
>  gcc/value-range.h     | 30 ++++++++++++++++++++++------
>  3 files changed, 53 insertions(+), 35 deletions(-)
>
> diff --git a/gcc/range-op-float.cc b/gcc/range-op-float.cc
> index 2bd3dc9253f..15ba19c2deb 100644
> --- a/gcc/range-op-float.cc
> +++ b/gcc/range-op-float.cc
> @@ -232,7 +232,8 @@ build_le (frange &r, tree type, const frange &val)
>  {
>    gcc_checking_assert (!val.known_isnan ());
>
> -  r.set (type, dconstninf, val.upper_bound ());
> +  REAL_VALUE_TYPE ninf = *TREE_REAL_CST_PTR (vrp_val_min (type));
> +  r.set (type, ninf, val.upper_bound ());
>
>    // Add both zeros if there's the possibility of zero equality.
>    frange_add_zeros (r, type);
> @@ -257,7 +258,8 @@ build_lt (frange &r, tree type, const frange &val)
>        return false;
>      }
>    // We only support closed intervals.
> -  r.set (type, dconstninf, val.upper_bound ());
> +  REAL_VALUE_TYPE ninf = *TREE_REAL_CST_PTR (vrp_val_min (type));
> +  r.set (type, ninf, val.upper_bound ());
>    return true;
>  }
>
> @@ -268,7 +270,8 @@ build_ge (frange &r, tree type, const frange &val)
>  {
>    gcc_checking_assert (!val.known_isnan ());
>
> -  r.set (type, val.lower_bound (), dconstinf);
> +  REAL_VALUE_TYPE inf = *TREE_REAL_CST_PTR (vrp_val_max (type));
> +  r.set (type, val.lower_bound (), inf);
>
>    // Add both zeros if there's the possibility of zero equality.
>    frange_add_zeros (r, type);
> @@ -294,7 +297,8 @@ build_gt (frange &r, tree type, const frange &val)
>      }
>
>    // We only support closed intervals.
> -  r.set (type, val.lower_bound (), dconstinf);
> +  REAL_VALUE_TYPE inf = *TREE_REAL_CST_PTR (vrp_val_max (type));
> +  r.set (type, val.lower_bound (), inf);
>    return true;
>  }
>
> diff --git a/gcc/value-range.cc b/gcc/value-range.cc
> index 7e8028eced2..e57d60e1bac 100644
> --- a/gcc/value-range.cc
> +++ b/gcc/value-range.cc
> @@ -338,6 +338,18 @@ frange::set (tree min, tree max, value_range_kind kind)
>        m_neg_nan = false;
>      }
>
> +  // For -ffinite-math-only we can drop ranges outside the
> +  // representable numbers to min/max for the type.
> +  if (flag_finite_math_only)
> +    {
> +      REAL_VALUE_TYPE min_repr = *TREE_REAL_CST_PTR (vrp_val_min (m_type));
> +      REAL_VALUE_TYPE max_repr = *TREE_REAL_CST_PTR (vrp_val_max (m_type));
> +      if (real_less (&m_min, &min_repr))
> +       m_min = min_repr;
> +      if (real_less (&max_repr, &m_max))
> +       m_max = max_repr;

I think you want to re-formulate that in terms of real_isinf() and
change those to the max representable values.

> +    }
> +
>    // Check for swapped ranges.
>    gcc_checking_assert (tree_compare (LE_EXPR, min, max));
>
> @@ -371,8 +383,8 @@ bool
>  frange::normalize_kind ()
>  {
>    if (m_kind == VR_RANGE
> -      && real_isinf (&m_min, 1)
> -      && real_isinf (&m_max, 0))
> +      && vrp_val_is_min (build_real (m_type, m_min))
> +      && vrp_val_is_max (build_real (m_type, m_max)))

I think this suggests that keeping +-Inf might be the better choice.
At least you want to change vrp_val_is_min/max to take a REAL_VALUE_TYPE
to avoid building four tree nodes for just this compare?

>      {
>        if (m_pos_nan && m_neg_nan)
>         {
> @@ -385,8 +397,8 @@ frange::normalize_kind ()
>        if (!m_pos_nan || !m_neg_nan)
>         {
>           m_kind = VR_RANGE;
> -         m_min = dconstninf;
> -         m_max = dconstinf;
> +         m_min = *TREE_REAL_CST_PTR (vrp_val_min (m_type));
> +         m_max = *TREE_REAL_CST_PTR (vrp_val_max (m_type));
>           return true;
>         }
>      }
> @@ -706,8 +718,8 @@ frange::verify_range ()
>      case VR_VARYING:
>        gcc_checking_assert (m_type);
>        gcc_checking_assert (m_pos_nan && m_neg_nan);
> -      gcc_checking_assert (real_isinf (&m_min, 1));
> -      gcc_checking_assert (real_isinf (&m_max, 0));
> +      gcc_checking_assert (vrp_val_is_min (build_real (m_type, m_min)));
> +      gcc_checking_assert (vrp_val_is_max (build_real (m_type, m_max)));
>        return;
>      case VR_RANGE:
>        gcc_checking_assert (m_type);
> @@ -732,7 +744,8 @@ frange::verify_range ()
>    // If all the properties are clear, we better not span the entire
>    // domain, because that would make us varying.
>    if (m_pos_nan && m_neg_nan)
> -    gcc_checking_assert (!real_isinf (&m_min, 1) || !real_isinf (&m_max, 0));
> +    gcc_checking_assert (!vrp_val_is_min (build_real (m_type, m_min))
> +                        || !vrp_val_is_max (build_real (m_type, m_max)));
>  }
>
>  // We can't do much with nonzeros yet.
> @@ -779,7 +792,7 @@ frange::zero_p () const
>  void
>  frange::set_nonnegative (tree type)
>  {
> -  set (type, dconst0, dconstinf);
> +  set (type, dconst0, *TREE_REAL_CST_PTR (vrp_val_max (type)));
>
>    // Set +NAN as the only possibility.
>    if (HONOR_NANS (type))
> @@ -3886,23 +3899,6 @@ range_tests_floats ()
>    r0.clear_nan ();
>    ASSERT_FALSE (r0.varying_p ());
>
> -  // The endpoints of a VARYING are +-INF.
> -  r0.set_varying (float_type_node);
> -  ASSERT_TRUE (real_identical (&r0.lower_bound (), &dconstninf));
> -  ASSERT_TRUE (real_identical (&r0.upper_bound (), &dconstinf));
> -
> -  // The maximum representable range for a type is still a subset of VARYING.
> -  REAL_VALUE_TYPE q, r;
> -  real_min_representable (&q, float_type_node);
> -  real_max_representable (&r, float_type_node);
> -  r0 = frange (float_type_node, q, r);
> -  // r0 is not a varying, because it does not include -INF/+INF.
> -  ASSERT_FALSE (r0.varying_p ());
> -  // The upper bound of r0 must be less than +INF.
> -  ASSERT_TRUE (real_less (&r0.upper_bound (), &dconstinf));
> -  // The lower bound of r0 must be greater than -INF.
> -  ASSERT_TRUE (real_less (&dconstninf, &r0.lower_bound ()));
> -
>    // For most architectures, where float and double are different
>    // sizes, having the same endpoints does not necessarily mean the
>    // ranges are equal.
> diff --git a/gcc/value-range.h b/gcc/value-range.h
> index 3668b331187..74879b76b40 100644
> --- a/gcc/value-range.h
> +++ b/gcc/value-range.h
> @@ -593,6 +593,8 @@ extern void dump_value_range (FILE *, const vrange *);
>  extern bool vrp_val_is_min (const_tree);
>  extern bool vrp_val_is_max (const_tree);
>  extern bool vrp_operand_equal_p (const_tree, const_tree);
> +inline void real_max_representable (REAL_VALUE_TYPE *r, const_tree type);
> +inline void real_min_representable (REAL_VALUE_TYPE *r, const_tree type);
>
>  inline value_range_kind
>  vrange::kind () const
> @@ -1009,7 +1011,15 @@ vrp_val_max (const_tree type)
>        return wide_int_to_tree (const_cast<tree> (type), max);
>      }
>    if (frange::supports_p (type))
> -    return build_real (const_cast <tree> (type), dconstinf);
> +    {
> +      if (flag_finite_math_only)
> +       {
> +         REAL_VALUE_TYPE r;
> +         real_max_representable (&r, type);
> +         return build_real (const_cast <tree> (type), r);
> +       }
> +      return build_real (const_cast <tree> (type), dconstinf);

Overall there's too many places affected IMHO.  The above also shows
we're building trees a lot - note that REAL_CST are _not_ shared, so
each time you call build_real a new REAL_CST tree node is allocated
(and later GCed if no longer used).

I thought vrp_val_min/max are legacy by now ...

That said, using trees for the range representation might not be the
very best thing to do, it's unnecessarily wrapping things.

> +    }
>    return NULL_TREE;
>  }
>
> @@ -1023,7 +1033,15 @@ vrp_val_min (const_tree type)
>    if (POINTER_TYPE_P (type))
>      return build_zero_cst (const_cast<tree> (type));
>    if (frange::supports_p (type))
> -    return build_real (const_cast <tree> (type), dconstninf);
> +    {
> +      if (flag_finite_math_only)
> +       {
> +         REAL_VALUE_TYPE r;
> +         real_min_representable (&r, type);
> +         return build_real (const_cast <tree> (type), r);
> +       }
> +      return build_real (const_cast <tree> (type), dconstninf);
> +    }
>    return NULL_TREE;
>  }
>
> @@ -1073,8 +1091,8 @@ frange::set_varying (tree type)
>  {
>    m_kind = VR_VARYING;
>    m_type = type;
> -  m_min = dconstninf;
> -  m_max = dconstinf;
> +  m_min = *TREE_REAL_CST_PTR (vrp_val_min (type));
> +  m_max = *TREE_REAL_CST_PTR (vrp_val_max (type));
>    m_pos_nan = true;
>    m_neg_nan = true;
>  }
> @@ -1133,7 +1151,7 @@ frange::clear_nan ()
>  // Set R to maximum representable value for TYPE.
>
>  inline void
> -real_max_representable (REAL_VALUE_TYPE *r, tree type)
> +real_max_representable (REAL_VALUE_TYPE *r, const_tree type)
>  {
>    char buf[128];
>    get_max_float (REAL_MODE_FORMAT (TYPE_MODE (type)),
> @@ -1145,7 +1163,7 @@ real_max_representable (REAL_VALUE_TYPE *r, tree type)
>  // Set R to minimum representable value for TYPE.
>
>  inline void
> -real_min_representable (REAL_VALUE_TYPE *r, tree type)
> +real_min_representable (REAL_VALUE_TYPE *r, const_tree type)
>  {
>    real_max_representable (r, type);
>    *r = real_value_negate (r);
> --
> 2.37.1
>
  

Ughhh, my bad.  I had reworked this as soon as Jakub said we couldn't
cache the min/max in TYPE_MIN/MAX_VALUE, but forgot to send it.  And
yes...the incessant wrapping was very annoying.  It's all fixed.

Let me know what you think.
Aldy

On Fri, Sep 23, 2022 at 9:04 AM Richard Biener
<richard.guenther@gmail.com> wrote:
>
> On Thu, Sep 22, 2022 at 6:49 PM Aldy Hernandez <aldyh@redhat.com> wrote:
> >
> > Similarly to how we drop NANs to UNDEFINED when -ffinite-math-only, I
> > think we can drop the numbers outside of the min/max representable
> > numbers to the representable number.
> >
> > This means the endpoings to VR_VARYING for -ffinite-math-only can now
> > be the min/max representable, instead of -INF and +INF.
> >
> > Saturating in the setter means that the upcoming implementation for
> > binary operators no longer have to worry about doing the right
> > thing for -ffinite-math-only.  If the range goes outside the limits,
> > it'll get chopped down.
> >
> > How does this look?
> >
> > Tested on x86-64 Linux.
> >
> > gcc/ChangeLog:
> >
> >         * range-op-float.cc (build_le): Use vrp_val_*.
> >         (build_lt): Same.
> >         (build_ge): Same.
> >         (build_gt): Same.
> >         * value-range.cc (frange::set): Chop ranges outside of the
> >         representable numbers for -ffinite-math-only.
> >         (frange::normalize_kind): Use vrp_val*.
> >         (frange::verify_range): Same.
> >         (frange::set_nonnegative): Same.
> >         (range_tests_floats): Remove tests that depend on -INF and +INF.
> >         * value-range.h (real_max_representable): Add prototype.
> >         (real_min_representable): Same.
> >         (vrp_val_max): Set max representable number for
> >         -ffinite-math-only.
> >         (vrp_val_min): Same but for min.
> >         (frange::set_varying): Use vrp_val*.
> > ---
> >  gcc/range-op-float.cc | 12 +++++++----
> >  gcc/value-range.cc    | 46 ++++++++++++++++++++-----------------------
> >  gcc/value-range.h     | 30 ++++++++++++++++++++++------
> >  3 files changed, 53 insertions(+), 35 deletions(-)
> >
> > diff --git a/gcc/range-op-float.cc b/gcc/range-op-float.cc
> > index 2bd3dc9253f..15ba19c2deb 100644
> > --- a/gcc/range-op-float.cc
> > +++ b/gcc/range-op-float.cc
> > @@ -232,7 +232,8 @@ build_le (frange &r, tree type, const frange &val)
> >  {
> >    gcc_checking_assert (!val.known_isnan ());
> >
> > -  r.set (type, dconstninf, val.upper_bound ());
> > +  REAL_VALUE_TYPE ninf = *TREE_REAL_CST_PTR (vrp_val_min (type));
> > +  r.set (type, ninf, val.upper_bound ());
> >
> >    // Add both zeros if there's the possibility of zero equality.
> >    frange_add_zeros (r, type);
> > @@ -257,7 +258,8 @@ build_lt (frange &r, tree type, const frange &val)
> >        return false;
> >      }
> >    // We only support closed intervals.
> > -  r.set (type, dconstninf, val.upper_bound ());
> > +  REAL_VALUE_TYPE ninf = *TREE_REAL_CST_PTR (vrp_val_min (type));
> > +  r.set (type, ninf, val.upper_bound ());
> >    return true;
> >  }
> >
> > @@ -268,7 +270,8 @@ build_ge (frange &r, tree type, const frange &val)
> >  {
> >    gcc_checking_assert (!val.known_isnan ());
> >
> > -  r.set (type, val.lower_bound (), dconstinf);
> > +  REAL_VALUE_TYPE inf = *TREE_REAL_CST_PTR (vrp_val_max (type));
> > +  r.set (type, val.lower_bound (), inf);
> >
> >    // Add both zeros if there's the possibility of zero equality.
> >    frange_add_zeros (r, type);
> > @@ -294,7 +297,8 @@ build_gt (frange &r, tree type, const frange &val)
> >      }
> >
> >    // We only support closed intervals.
> > -  r.set (type, val.lower_bound (), dconstinf);
> > +  REAL_VALUE_TYPE inf = *TREE_REAL_CST_PTR (vrp_val_max (type));
> > +  r.set (type, val.lower_bound (), inf);
> >    return true;
> >  }
> >
> > diff --git a/gcc/value-range.cc b/gcc/value-range.cc
> > index 7e8028eced2..e57d60e1bac 100644
> > --- a/gcc/value-range.cc
> > +++ b/gcc/value-range.cc
> > @@ -338,6 +338,18 @@ frange::set (tree min, tree max, value_range_kind kind)
> >        m_neg_nan = false;
> >      }
> >
> > +  // For -ffinite-math-only we can drop ranges outside the
> > +  // representable numbers to min/max for the type.
> > +  if (flag_finite_math_only)
> > +    {
> > +      REAL_VALUE_TYPE min_repr = *TREE_REAL_CST_PTR (vrp_val_min (m_type));
> > +      REAL_VALUE_TYPE max_repr = *TREE_REAL_CST_PTR (vrp_val_max (m_type));
> > +      if (real_less (&m_min, &min_repr))
> > +       m_min = min_repr;
> > +      if (real_less (&max_repr, &m_max))
> > +       m_max = max_repr;
>
> I think you want to re-formulate that in terms of real_isinf() and
> change those to the max representable values.
>
> > +    }
> > +
> >    // Check for swapped ranges.
> >    gcc_checking_assert (tree_compare (LE_EXPR, min, max));
> >
> > @@ -371,8 +383,8 @@ bool
> >  frange::normalize_kind ()
> >  {
> >    if (m_kind == VR_RANGE
> > -      && real_isinf (&m_min, 1)
> > -      && real_isinf (&m_max, 0))
> > +      && vrp_val_is_min (build_real (m_type, m_min))
> > +      && vrp_val_is_max (build_real (m_type, m_max)))
>
> I think this suggests that keeping +-Inf might be the better choice.
> At least you want to change vrp_val_is_min/max to take a REAL_VALUE_TYPE
> to avoid building four tree nodes for just this compare?
>
> >      {
> >        if (m_pos_nan && m_neg_nan)
> >         {
> > @@ -385,8 +397,8 @@ frange::normalize_kind ()
> >        if (!m_pos_nan || !m_neg_nan)
> >         {
> >           m_kind = VR_RANGE;
> > -         m_min = dconstninf;
> > -         m_max = dconstinf;
> > +         m_min = *TREE_REAL_CST_PTR (vrp_val_min (m_type));
> > +         m_max = *TREE_REAL_CST_PTR (vrp_val_max (m_type));
> >           return true;
> >         }
> >      }
> > @@ -706,8 +718,8 @@ frange::verify_range ()
> >      case VR_VARYING:
> >        gcc_checking_assert (m_type);
> >        gcc_checking_assert (m_pos_nan && m_neg_nan);
> > -      gcc_checking_assert (real_isinf (&m_min, 1));
> > -      gcc_checking_assert (real_isinf (&m_max, 0));
> > +      gcc_checking_assert (vrp_val_is_min (build_real (m_type, m_min)));
> > +      gcc_checking_assert (vrp_val_is_max (build_real (m_type, m_max)));
> >        return;
> >      case VR_RANGE:
> >        gcc_checking_assert (m_type);
> > @@ -732,7 +744,8 @@ frange::verify_range ()
> >    // If all the properties are clear, we better not span the entire
> >    // domain, because that would make us varying.
> >    if (m_pos_nan && m_neg_nan)
> > -    gcc_checking_assert (!real_isinf (&m_min, 1) || !real_isinf (&m_max, 0));
> > +    gcc_checking_assert (!vrp_val_is_min (build_real (m_type, m_min))
> > +                        || !vrp_val_is_max (build_real (m_type, m_max)));
> >  }
> >
> >  // We can't do much with nonzeros yet.
> > @@ -779,7 +792,7 @@ frange::zero_p () const
> >  void
> >  frange::set_nonnegative (tree type)
> >  {
> > -  set (type, dconst0, dconstinf);
> > +  set (type, dconst0, *TREE_REAL_CST_PTR (vrp_val_max (type)));
> >
> >    // Set +NAN as the only possibility.
> >    if (HONOR_NANS (type))
> > @@ -3886,23 +3899,6 @@ range_tests_floats ()
> >    r0.clear_nan ();
> >    ASSERT_FALSE (r0.varying_p ());
> >
> > -  // The endpoints of a VARYING are +-INF.
> > -  r0.set_varying (float_type_node);
> > -  ASSERT_TRUE (real_identical (&r0.lower_bound (), &dconstninf));
> > -  ASSERT_TRUE (real_identical (&r0.upper_bound (), &dconstinf));
> > -
> > -  // The maximum representable range for a type is still a subset of VARYING.
> > -  REAL_VALUE_TYPE q, r;
> > -  real_min_representable (&q, float_type_node);
> > -  real_max_representable (&r, float_type_node);
> > -  r0 = frange (float_type_node, q, r);
> > -  // r0 is not a varying, because it does not include -INF/+INF.
> > -  ASSERT_FALSE (r0.varying_p ());
> > -  // The upper bound of r0 must be less than +INF.
> > -  ASSERT_TRUE (real_less (&r0.upper_bound (), &dconstinf));
> > -  // The lower bound of r0 must be greater than -INF.
> > -  ASSERT_TRUE (real_less (&dconstninf, &r0.lower_bound ()));
> > -
> >    // For most architectures, where float and double are different
> >    // sizes, having the same endpoints does not necessarily mean the
> >    // ranges are equal.
> > diff --git a/gcc/value-range.h b/gcc/value-range.h
> > index 3668b331187..74879b76b40 100644
> > --- a/gcc/value-range.h
> > +++ b/gcc/value-range.h
> > @@ -593,6 +593,8 @@ extern void dump_value_range (FILE *, const vrange *);
> >  extern bool vrp_val_is_min (const_tree);
> >  extern bool vrp_val_is_max (const_tree);
> >  extern bool vrp_operand_equal_p (const_tree, const_tree);
> > +inline void real_max_representable (REAL_VALUE_TYPE *r, const_tree type);
> > +inline void real_min_representable (REAL_VALUE_TYPE *r, const_tree type);
> >
> >  inline value_range_kind
> >  vrange::kind () const
> > @@ -1009,7 +1011,15 @@ vrp_val_max (const_tree type)
> >        return wide_int_to_tree (const_cast<tree> (type), max);
> >      }
> >    if (frange::supports_p (type))
> > -    return build_real (const_cast <tree> (type), dconstinf);
> > +    {
> > +      if (flag_finite_math_only)
> > +       {
> > +         REAL_VALUE_TYPE r;
> > +         real_max_representable (&r, type);
> > +         return build_real (const_cast <tree> (type), r);
> > +       }
> > +      return build_real (const_cast <tree> (type), dconstinf);
>
> Overall there's too many places affected IMHO.  The above also shows
> we're building trees a lot - note that REAL_CST are _not_ shared, so
> each time you call build_real a new REAL_CST tree node is allocated
> (and later GCed if no longer used).
>
> I thought vrp_val_min/max are legacy by now ...
>
> That said, using trees for the range representation might not be the
> very best thing to do, it's unnecessarily wrapping things.
>
> > +    }
> >    return NULL_TREE;
> >  }
> >
> > @@ -1023,7 +1033,15 @@ vrp_val_min (const_tree type)
> >    if (POINTER_TYPE_P (type))
> >      return build_zero_cst (const_cast<tree> (type));
> >    if (frange::supports_p (type))
> > -    return build_real (const_cast <tree> (type), dconstninf);
> > +    {
> > +      if (flag_finite_math_only)
> > +       {
> > +         REAL_VALUE_TYPE r;
> > +         real_min_representable (&r, type);
> > +         return build_real (const_cast <tree> (type), r);
> > +       }
> > +      return build_real (const_cast <tree> (type), dconstninf);
> > +    }
> >    return NULL_TREE;
> >  }
> >
> > @@ -1073,8 +1091,8 @@ frange::set_varying (tree type)
> >  {
> >    m_kind = VR_VARYING;
> >    m_type = type;
> > -  m_min = dconstninf;
> > -  m_max = dconstinf;
> > +  m_min = *TREE_REAL_CST_PTR (vrp_val_min (type));
> > +  m_max = *TREE_REAL_CST_PTR (vrp_val_max (type));
> >    m_pos_nan = true;
> >    m_neg_nan = true;
> >  }
> > @@ -1133,7 +1151,7 @@ frange::clear_nan ()
> >  // Set R to maximum representable value for TYPE.
> >
> >  inline void
> > -real_max_representable (REAL_VALUE_TYPE *r, tree type)
> > +real_max_representable (REAL_VALUE_TYPE *r, const_tree type)
> >  {
> >    char buf[128];
> >    get_max_float (REAL_MODE_FORMAT (TYPE_MODE (type)),
> > @@ -1145,7 +1163,7 @@ real_max_representable (REAL_VALUE_TYPE *r, tree type)
> >  // Set R to minimum representable value for TYPE.
> >
> >  inline void
> > -real_min_representable (REAL_VALUE_TYPE *r, tree type)
> > +real_min_representable (REAL_VALUE_TYPE *r, const_tree type)
> >  {
> >    real_max_representable (r, type);
> >    *r = real_value_negate (r);
> > --
> > 2.37.1
> >
>
  

On Fri, Sep 23, 2022 at 9:21 AM Aldy Hernandez <aldyh@redhat.com> wrote:
>
> Ughhh, my bad.  I had reworked this as soon as Jakub said we couldn't
> cache the min/max in TYPE_MIN/MAX_VALUE, but forgot to send it.  And
> yes...the incessant wrapping was very annoying.  It's all fixed.
>
> Let me know what you think.

Much better.

Thanks,
Richard.

> Aldy
>
> On Fri, Sep 23, 2022 at 9:04 AM Richard Biener
> <richard.guenther@gmail.com> wrote:
> >
> > On Thu, Sep 22, 2022 at 6:49 PM Aldy Hernandez <aldyh@redhat.com> wrote:
> > >
> > > Similarly to how we drop NANs to UNDEFINED when -ffinite-math-only, I
> > > think we can drop the numbers outside of the min/max representable
> > > numbers to the representable number.
> > >
> > > This means the endpoings to VR_VARYING for -ffinite-math-only can now
> > > be the min/max representable, instead of -INF and +INF.
> > >
> > > Saturating in the setter means that the upcoming implementation for
> > > binary operators no longer have to worry about doing the right
> > > thing for -ffinite-math-only.  If the range goes outside the limits,
> > > it'll get chopped down.
> > >
> > > How does this look?
> > >
> > > Tested on x86-64 Linux.
> > >
> > > gcc/ChangeLog:
> > >
> > >         * range-op-float.cc (build_le): Use vrp_val_*.
> > >         (build_lt): Same.
> > >         (build_ge): Same.
> > >         (build_gt): Same.
> > >         * value-range.cc (frange::set): Chop ranges outside of the
> > >         representable numbers for -ffinite-math-only.
> > >         (frange::normalize_kind): Use vrp_val*.
> > >         (frange::verify_range): Same.
> > >         (frange::set_nonnegative): Same.
> > >         (range_tests_floats): Remove tests that depend on -INF and +INF.
> > >         * value-range.h (real_max_representable): Add prototype.
> > >         (real_min_representable): Same.
> > >         (vrp_val_max): Set max representable number for
> > >         -ffinite-math-only.
> > >         (vrp_val_min): Same but for min.
> > >         (frange::set_varying): Use vrp_val*.
> > > ---
> > >  gcc/range-op-float.cc | 12 +++++++----
> > >  gcc/value-range.cc    | 46 ++++++++++++++++++++-----------------------
> > >  gcc/value-range.h     | 30 ++++++++++++++++++++++------
> > >  3 files changed, 53 insertions(+), 35 deletions(-)
> > >
> > > diff --git a/gcc/range-op-float.cc b/gcc/range-op-float.cc
> > > index 2bd3dc9253f..15ba19c2deb 100644
> > > --- a/gcc/range-op-float.cc
> > > +++ b/gcc/range-op-float.cc
> > > @@ -232,7 +232,8 @@ build_le (frange &r, tree type, const frange &val)
> > >  {
> > >    gcc_checking_assert (!val.known_isnan ());
> > >
> > > -  r.set (type, dconstninf, val.upper_bound ());
> > > +  REAL_VALUE_TYPE ninf = *TREE_REAL_CST_PTR (vrp_val_min (type));
> > > +  r.set (type, ninf, val.upper_bound ());
> > >
> > >    // Add both zeros if there's the possibility of zero equality.
> > >    frange_add_zeros (r, type);
> > > @@ -257,7 +258,8 @@ build_lt (frange &r, tree type, const frange &val)
> > >        return false;
> > >      }
> > >    // We only support closed intervals.
> > > -  r.set (type, dconstninf, val.upper_bound ());
> > > +  REAL_VALUE_TYPE ninf = *TREE_REAL_CST_PTR (vrp_val_min (type));
> > > +  r.set (type, ninf, val.upper_bound ());
> > >    return true;
> > >  }
> > >
> > > @@ -268,7 +270,8 @@ build_ge (frange &r, tree type, const frange &val)
> > >  {
> > >    gcc_checking_assert (!val.known_isnan ());
> > >
> > > -  r.set (type, val.lower_bound (), dconstinf);
> > > +  REAL_VALUE_TYPE inf = *TREE_REAL_CST_PTR (vrp_val_max (type));
> > > +  r.set (type, val.lower_bound (), inf);
> > >
> > >    // Add both zeros if there's the possibility of zero equality.
> > >    frange_add_zeros (r, type);
> > > @@ -294,7 +297,8 @@ build_gt (frange &r, tree type, const frange &val)
> > >      }
> > >
> > >    // We only support closed intervals.
> > > -  r.set (type, val.lower_bound (), dconstinf);
> > > +  REAL_VALUE_TYPE inf = *TREE_REAL_CST_PTR (vrp_val_max (type));
> > > +  r.set (type, val.lower_bound (), inf);
> > >    return true;
> > >  }
> > >
> > > diff --git a/gcc/value-range.cc b/gcc/value-range.cc
> > > index 7e8028eced2..e57d60e1bac 100644
> > > --- a/gcc/value-range.cc
> > > +++ b/gcc/value-range.cc
> > > @@ -338,6 +338,18 @@ frange::set (tree min, tree max, value_range_kind kind)
> > >        m_neg_nan = false;
> > >      }
> > >
> > > +  // For -ffinite-math-only we can drop ranges outside the
> > > +  // representable numbers to min/max for the type.
> > > +  if (flag_finite_math_only)
> > > +    {
> > > +      REAL_VALUE_TYPE min_repr = *TREE_REAL_CST_PTR (vrp_val_min (m_type));
> > > +      REAL_VALUE_TYPE max_repr = *TREE_REAL_CST_PTR (vrp_val_max (m_type));
> > > +      if (real_less (&m_min, &min_repr))
> > > +       m_min = min_repr;
> > > +      if (real_less (&max_repr, &m_max))
> > > +       m_max = max_repr;
> >
> > I think you want to re-formulate that in terms of real_isinf() and
> > change those to the max representable values.
> >
> > > +    }
> > > +
> > >    // Check for swapped ranges.
> > >    gcc_checking_assert (tree_compare (LE_EXPR, min, max));
> > >
> > > @@ -371,8 +383,8 @@ bool
> > >  frange::normalize_kind ()
> > >  {
> > >    if (m_kind == VR_RANGE
> > > -      && real_isinf (&m_min, 1)
> > > -      && real_isinf (&m_max, 0))
> > > +      && vrp_val_is_min (build_real (m_type, m_min))
> > > +      && vrp_val_is_max (build_real (m_type, m_max)))
> >
> > I think this suggests that keeping +-Inf might be the better choice.
> > At least you want to change vrp_val_is_min/max to take a REAL_VALUE_TYPE
> > to avoid building four tree nodes for just this compare?
> >
> > >      {
> > >        if (m_pos_nan && m_neg_nan)
> > >         {
> > > @@ -385,8 +397,8 @@ frange::normalize_kind ()
> > >        if (!m_pos_nan || !m_neg_nan)
> > >         {
> > >           m_kind = VR_RANGE;
> > > -         m_min = dconstninf;
> > > -         m_max = dconstinf;
> > > +         m_min = *TREE_REAL_CST_PTR (vrp_val_min (m_type));
> > > +         m_max = *TREE_REAL_CST_PTR (vrp_val_max (m_type));
> > >           return true;
> > >         }
> > >      }
> > > @@ -706,8 +718,8 @@ frange::verify_range ()
> > >      case VR_VARYING:
> > >        gcc_checking_assert (m_type);
> > >        gcc_checking_assert (m_pos_nan && m_neg_nan);
> > > -      gcc_checking_assert (real_isinf (&m_min, 1));
> > > -      gcc_checking_assert (real_isinf (&m_max, 0));
> > > +      gcc_checking_assert (vrp_val_is_min (build_real (m_type, m_min)));
> > > +      gcc_checking_assert (vrp_val_is_max (build_real (m_type, m_max)));
> > >        return;
> > >      case VR_RANGE:
> > >        gcc_checking_assert (m_type);
> > > @@ -732,7 +744,8 @@ frange::verify_range ()
> > >    // If all the properties are clear, we better not span the entire
> > >    // domain, because that would make us varying.
> > >    if (m_pos_nan && m_neg_nan)
> > > -    gcc_checking_assert (!real_isinf (&m_min, 1) || !real_isinf (&m_max, 0));
> > > +    gcc_checking_assert (!vrp_val_is_min (build_real (m_type, m_min))
> > > +                        || !vrp_val_is_max (build_real (m_type, m_max)));
> > >  }
> > >
> > >  // We can't do much with nonzeros yet.
> > > @@ -779,7 +792,7 @@ frange::zero_p () const
> > >  void
> > >  frange::set_nonnegative (tree type)
> > >  {
> > > -  set (type, dconst0, dconstinf);
> > > +  set (type, dconst0, *TREE_REAL_CST_PTR (vrp_val_max (type)));
> > >
> > >    // Set +NAN as the only possibility.
> > >    if (HONOR_NANS (type))
> > > @@ -3886,23 +3899,6 @@ range_tests_floats ()
> > >    r0.clear_nan ();
> > >    ASSERT_FALSE (r0.varying_p ());
> > >
> > > -  // The endpoints of a VARYING are +-INF.
> > > -  r0.set_varying (float_type_node);
> > > -  ASSERT_TRUE (real_identical (&r0.lower_bound (), &dconstninf));
> > > -  ASSERT_TRUE (real_identical (&r0.upper_bound (), &dconstinf));
> > > -
> > > -  // The maximum representable range for a type is still a subset of VARYING.
> > > -  REAL_VALUE_TYPE q, r;
> > > -  real_min_representable (&q, float_type_node);
> > > -  real_max_representable (&r, float_type_node);
> > > -  r0 = frange (float_type_node, q, r);
> > > -  // r0 is not a varying, because it does not include -INF/+INF.
> > > -  ASSERT_FALSE (r0.varying_p ());
> > > -  // The upper bound of r0 must be less than +INF.
> > > -  ASSERT_TRUE (real_less (&r0.upper_bound (), &dconstinf));
> > > -  // The lower bound of r0 must be greater than -INF.
> > > -  ASSERT_TRUE (real_less (&dconstninf, &r0.lower_bound ()));
> > > -
> > >    // For most architectures, where float and double are different
> > >    // sizes, having the same endpoints does not necessarily mean the
> > >    // ranges are equal.
> > > diff --git a/gcc/value-range.h b/gcc/value-range.h
> > > index 3668b331187..74879b76b40 100644
> > > --- a/gcc/value-range.h
> > > +++ b/gcc/value-range.h
> > > @@ -593,6 +593,8 @@ extern void dump_value_range (FILE *, const vrange *);
> > >  extern bool vrp_val_is_min (const_tree);
> > >  extern bool vrp_val_is_max (const_tree);
> > >  extern bool vrp_operand_equal_p (const_tree, const_tree);
> > > +inline void real_max_representable (REAL_VALUE_TYPE *r, const_tree type);
> > > +inline void real_min_representable (REAL_VALUE_TYPE *r, const_tree type);
> > >
> > >  inline value_range_kind
> > >  vrange::kind () const
> > > @@ -1009,7 +1011,15 @@ vrp_val_max (const_tree type)
> > >        return wide_int_to_tree (const_cast<tree> (type), max);
> > >      }
> > >    if (frange::supports_p (type))
> > > -    return build_real (const_cast <tree> (type), dconstinf);
> > > +    {
> > > +      if (flag_finite_math_only)
> > > +       {
> > > +         REAL_VALUE_TYPE r;
> > > +         real_max_representable (&r, type);
> > > +         return build_real (const_cast <tree> (type), r);
> > > +       }
> > > +      return build_real (const_cast <tree> (type), dconstinf);
> >
> > Overall there's too many places affected IMHO.  The above also shows
> > we're building trees a lot - note that REAL_CST are _not_ shared, so
> > each time you call build_real a new REAL_CST tree node is allocated
> > (and later GCed if no longer used).
> >
> > I thought vrp_val_min/max are legacy by now ...
> >
> > That said, using trees for the range representation might not be the
> > very best thing to do, it's unnecessarily wrapping things.
> >
> > > +    }
> > >    return NULL_TREE;
> > >  }
> > >
> > > @@ -1023,7 +1033,15 @@ vrp_val_min (const_tree type)
> > >    if (POINTER_TYPE_P (type))
> > >      return build_zero_cst (const_cast<tree> (type));
> > >    if (frange::supports_p (type))
> > > -    return build_real (const_cast <tree> (type), dconstninf);
> > > +    {
> > > +      if (flag_finite_math_only)
> > > +       {
> > > +         REAL_VALUE_TYPE r;
> > > +         real_min_representable (&r, type);
> > > +         return build_real (const_cast <tree> (type), r);
> > > +       }
> > > +      return build_real (const_cast <tree> (type), dconstninf);
> > > +    }
> > >    return NULL_TREE;
> > >  }
> > >
> > > @@ -1073,8 +1091,8 @@ frange::set_varying (tree type)
> > >  {
> > >    m_kind = VR_VARYING;
> > >    m_type = type;
> > > -  m_min = dconstninf;
> > > -  m_max = dconstinf;
> > > +  m_min = *TREE_REAL_CST_PTR (vrp_val_min (type));
> > > +  m_max = *TREE_REAL_CST_PTR (vrp_val_max (type));
> > >    m_pos_nan = true;
> > >    m_neg_nan = true;
> > >  }
> > > @@ -1133,7 +1151,7 @@ frange::clear_nan ()
> > >  // Set R to maximum representable value for TYPE.
> > >
> > >  inline void
> > > -real_max_representable (REAL_VALUE_TYPE *r, tree type)
> > > +real_max_representable (REAL_VALUE_TYPE *r, const_tree type)
> > >  {
> > >    char buf[128];
> > >    get_max_float (REAL_MODE_FORMAT (TYPE_MODE (type)),
> > > @@ -1145,7 +1163,7 @@ real_max_representable (REAL_VALUE_TYPE *r, tree type)
> > >  // Set R to minimum representable value for TYPE.
> > >
> > >  inline void
> > > -real_min_representable (REAL_VALUE_TYPE *r, tree type)
> > > +real_min_representable (REAL_VALUE_TYPE *r, const_tree type)
> > >  {
> > >    real_max_representable (r, type);
> > >    *r = real_value_negate (r);
> > > --
> > > 2.37.1
> > >
> >