[COMMITTED] Handle NANs in frange::operator== [PR109593]

[Aldy Hernandez via Gcc-patches]

This patch...
        commit 10e481b154c5fc63e6ce4b449ce86cecb87a6015
        Return true from operator== for two identical ranges containing NAN.

removed the check for NANs, which caused us to read from m_min and
m_max which are undefined for NANs.

gcc/ChangeLog:

        PR tree-optimization/109593
        * value-range.cc (frange::operator==): Handle NANs.
---
 gcc/value-range.cc | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/gcc/value-range.cc b/gcc/value-range.cc
index 17f4e1b9f59..97162413727 100644
--- a/gcc/value-range.cc
+++ b/gcc/value-range.cc
@@ -682,6 +682,16 @@ frange::operator== (const frange &src) const
       if (varying_p ())
        return types_compatible_p (m_type, src.m_type);
 
+      bool nan1 = known_isnan ();
+      bool nan2 = src.known_isnan ();
+      if (nan1 || nan2)
+       {
+         if (nan1 && nan2)
+           return (m_pos_nan == src.m_pos_nan
+                   && m_neg_nan == src.m_neg_nan);
+         return false;
+       }
+
       return (real_identical (&m_min, &src.m_min)
              && real_identical (&m_max, &src.m_max)
              && m_pos_nan == src.m_pos_nan
-- 
2.40.0