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

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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.

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*.
This commit is contained in:
Aldy Hernandez 2022-09-22 18:20:39 +02:00
parent 76dbbfe62c
commit b7fd7fb501
3 changed files with 94 additions and 45 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

18
gcc/range-op-float.cc
View file

@ -200,8 +200,7 @@ frelop_early_resolve (irange &r, tree type,
static inline void
frange_drop_inf (frange &r, tree type)
{
REAL_VALUE_TYPE max;
real_max_representable (&max, type);
REAL_VALUE_TYPE max = real_max_representable (type);
frange tmp (type, r.lower_bound (), max);
r.intersect (tmp);
}
@ -212,8 +211,7 @@ frange_drop_inf (frange &r, tree type)
static inline void
frange_drop_ninf (frange &r, tree type)
{
REAL_VALUE_TYPE min;
real_min_representable (&min, type);
REAL_VALUE_TYPE min = real_min_representable (type);
frange tmp (type, min, r.upper_bound ());
r.intersect (tmp);
}
@ -242,7 +240,8 @@ 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 = frange_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);
@ -267,7 +266,8 @@ 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 = frange_val_min (type);
r.set (type, ninf, val.upper_bound ());
return true;
}
@ -278,7 +278,8 @@ 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 = frange_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);
@ -304,7 +305,8 @@ 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 = frange_val_max (type);
r.set (type, val.lower_bound (), inf);
return true;
}

46
gcc/value-range.cc
View file

@ -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 = frange_val_min (m_type);
REAL_VALUE_TYPE max_repr = frange_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;
}
// 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))
&& frange_val_is_min (m_min, m_type)
&& frange_val_is_max (m_max, m_type))
{
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 = frange_val_min (m_type);
m_max = frange_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 (frange_val_is_min (m_min, m_type));
gcc_checking_assert (frange_val_is_max (m_max, m_type));
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 (!frange_val_is_min (m_min, m_type)
|| !frange_val_is_max (m_max, m_type));
}
// 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, frange_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.

75
gcc/value-range.h
View file

@ -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 REAL_VALUE_TYPE frange_val_min (const_tree type);
inline REAL_VALUE_TYPE frange_val_max (const_tree type);
inline value_range_kind
vrange::kind () const
@ -1009,7 +1011,10 @@ 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);
{
REAL_VALUE_TYPE r = frange_val_max (type);
return build_real (const_cast <tree> (type), r);
}
return NULL_TREE;
}
@ -1023,7 +1028,10 @@ 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);
{
REAL_VALUE_TYPE r = frange_val_min (type);
return build_real (const_cast <tree> (type), r);
}
return NULL_TREE;
}
@ -1073,8 +1081,8 @@ frange::set_varying (tree type)
{
m_kind = VR_VARYING;
m_type = type;
m_min = dconstninf;
m_max = dconstinf;
m_min = frange_val_min (type);
m_max = frange_val_max (type);
m_pos_nan = true;
m_neg_nan = true;
}
@ -1132,23 +1140,66 @@ frange::clear_nan ()
// Set R to maximum representable value for TYPE.
inline void
real_max_representable (REAL_VALUE_TYPE *r, tree type)
inline REAL_VALUE_TYPE
real_max_representable (const_tree type)
{
REAL_VALUE_TYPE r;
char buf[128];
get_max_float (REAL_MODE_FORMAT (TYPE_MODE (type)),
buf, sizeof (buf), false);
int res = real_from_string (r, buf);
int res = real_from_string (&r, buf);
gcc_checking_assert (!res);
return r;
}
// Set R to minimum representable value for TYPE.
// Return the minimum representable value for TYPE.
inline void
real_min_representable (REAL_VALUE_TYPE *r, tree type)
inline REAL_VALUE_TYPE
real_min_representable (const_tree type)
{
real_max_representable (r, type);
*r = real_value_negate (r);
REAL_VALUE_TYPE r = real_max_representable (type);
r = real_value_negate (&r);
return r;
}
// Return the minimum value for TYPE.
inline REAL_VALUE_TYPE
frange_val_min (const_tree type)
{
if (flag_finite_math_only)
return real_min_representable (type);
else
return dconstninf;
}
// Return the maximum value for TYPE.
inline REAL_VALUE_TYPE
frange_val_max (const_tree type)
{
if (flag_finite_math_only)
return real_max_representable (type);
else
return dconstinf;
}
// Return TRUE if R is the minimum value for TYPE.
inline bool
frange_val_is_min (const REAL_VALUE_TYPE &r, const_tree type)
{
REAL_VALUE_TYPE min = frange_val_min (type);
return real_identical (&min, &r);
}
// Return TRUE if R is the max value for TYPE.
inline bool
frange_val_is_max (const REAL_VALUE_TYPE &r, const_tree type)
{
REAL_VALUE_TYPE max = frange_val_max (type);
return real_identical (&max, &r);
}
// Build a signless NAN of type TYPE.