[gcc r14-174] Handle NANs in frange::operator== [PR109593]

[Aldy Hernandez <aldyh@gcc.gnu.org>]

https://gcc.gnu.org/g:5830953a446959c5d8d9b569ffcd3e3bb16a06dc

commit r14-174-g5830953a446959c5d8d9b569ffcd3e3bb16a06dc
Author: Aldy Hernandez <aldyh@redhat.com>
Date:   Sun Apr 23 08:04:55 2023 +0200

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

Diff:
---
 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