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* [gcc r13-2741] frange::set_nonnegative should not contain -NAN.
@ 2022-09-20 17:36 Aldy Hernandez
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From: Aldy Hernandez @ 2022-09-20 17:36 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:10d6109fe183d984a0377a7afe2854a0d794ebeb
commit r13-2741-g10d6109fe183d984a0377a7afe2854a0d794ebeb
Author: Aldy Hernandez <aldyh@redhat.com>
Date: Mon Sep 19 09:59:01 2022 +0200
frange::set_nonnegative should not contain -NAN.
A specifically nonnegative range should not contain -NAN, otherwise
signbit_p() would return false, because we'd be unsure of the sign.
PR 68097/tree-optimization
gcc/ChangeLog:
* value-range.cc (frange::set_nonnegative): Set +NAN.
(range_tests_signed_zeros): New test.
* value-range.h (frange::update_nan): New overload to set NAN sign.
Diff:
---
gcc/value-range.cc | 9 +++++++++
gcc/value-range.h | 14 ++++++++++++++
2 files changed, 23 insertions(+)
diff --git a/gcc/value-range.cc b/gcc/value-range.cc
index a8e3bb39bab..dc42b6d3120 100644
--- a/gcc/value-range.cc
+++ b/gcc/value-range.cc
@@ -775,6 +775,10 @@ void
frange::set_nonnegative (tree type)
{
set (type, dconst0, dconstinf);
+
+ // Set +NAN as the only possibility.
+ if (HONOR_NANS (type))
+ update_nan (/*sign=*/0);
}
// Here we copy between any two irange's. The ranges can be legacy or
@@ -3823,6 +3827,11 @@ range_tests_signed_zeros ()
r1.update_nan ();
r0.intersect (r1);
ASSERT_TRUE (r0.known_isnan ());
+
+ r0.set_nonnegative (float_type_node);
+ ASSERT_TRUE (r0.signbit_p (signbit) && !signbit);
+ if (HONOR_NANS (float_type_node))
+ ASSERT_TRUE (r0.maybe_isnan ());
}
static void
diff --git a/gcc/value-range.h b/gcc/value-range.h
index 795b1f00fdc..7d5584a9294 100644
--- a/gcc/value-range.h
+++ b/gcc/value-range.h
@@ -312,6 +312,7 @@ public:
const REAL_VALUE_TYPE &lower_bound () const;
const REAL_VALUE_TYPE &upper_bound () const;
void update_nan ();
+ void update_nan (bool sign);
void clear_nan ();
// fpclassify like API
@@ -1099,6 +1100,19 @@ frange::update_nan ()
verify_range ();
}
+// Like above, but set the sign of the NAN.
+
+inline void
+frange::update_nan (bool sign)
+{
+ gcc_checking_assert (!undefined_p ());
+ m_pos_nan = !sign;
+ m_neg_nan = sign;
+ normalize_kind ();
+ if (flag_checking)
+ verify_range ();
+}
+
// Clear the NAN bit and adjust the range.
inline void
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