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* [gcc r13-3860] Clear NAN when reading back a global range if necessary.
@ 2022-11-09 17:21 Aldy Hernandez
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From: Aldy Hernandez @ 2022-11-09 17:21 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:4eadbe80060ab6c45193a1a57fac84b035e1c328
commit r13-3860-g4eadbe80060ab6c45193a1a57fac84b035e1c328
Author: Aldy Hernandez <aldyh@redhat.com>
Date: Wed Nov 9 16:05:08 2022 +0100
Clear NAN when reading back a global range if necessary.
When reading back from the global store, we must clear the NAN bit if
necessary. The reason it's not happening is because the constructor
sets a NAN by default (when HONOR_NANS). We must be careful to clear
the NAN bit if the original range didn't have a NAN.
I have commented the reason we use the constructor instead of filling
out the fields by hand, because it wasn't clear at re-reading this
code.
PR 107569/tree-optimization
gcc/ChangeLog:
* value-range-storage.cc (frange_storage_slot::get_frange): Clear
NAN if appropriate.
* value-range.cc (range_tests_floats): New test.
Diff:
---
gcc/value-range-storage.cc | 9 ++++++++-
gcc/value-range.cc | 9 +++++++++
2 files changed, 17 insertions(+), 1 deletion(-)
diff --git a/gcc/value-range-storage.cc b/gcc/value-range-storage.cc
index 462447ba250..b57701f0ea1 100644
--- a/gcc/value-range-storage.cc
+++ b/gcc/value-range-storage.cc
@@ -276,13 +276,20 @@ frange_storage_slot::get_frange (frange &r, tree type) const
return;
}
- // Use the constructor because it will canonicalize the range.
+ // We use the constructor to create the new range instead of writing
+ // out the bits into the frange directly, because the global range
+ // being read may be being inlined into a function with different
+ // restrictions as when it was originally written. We want to make
+ // sure the resulting range is canonicalized correctly for the new
+ // consumer.
r = frange (type, m_min, m_max, m_kind);
// The constructor will set the NAN bits for HONOR_NANS, but we must
// make sure to set the NAN sign if known.
if (HONOR_NANS (type) && (m_pos_nan ^ m_neg_nan) == 1)
r.update_nan (m_neg_nan);
+ else if (!m_pos_nan && !m_neg_nan)
+ r.clear_nan ();
}
bool
diff --git a/gcc/value-range.cc b/gcc/value-range.cc
index 859c7fb4af9..852ac09f2c4 100644
--- a/gcc/value-range.cc
+++ b/gcc/value-range.cc
@@ -4051,6 +4051,15 @@ range_tests_floats ()
ASSERT_TRUE (real_isinf (&r0.lower_bound (), true));
ASSERT_TRUE (real_isinf (&r0.upper_bound (), true));
}
+
+ // Test that reading back a global range yields the same result as
+ // what we wrote into it.
+ tree ssa = make_temp_ssa_name (float_type_node, NULL, "blah");
+ r0.set_varying (float_type_node);
+ r0.clear_nan ();
+ set_range_info (ssa, r0);
+ get_global_range_query ()->range_of_expr (r1, ssa);
+ ASSERT_EQ (r0, r1);
}
// Run floating range tests for various combinations of NAN and INF
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