fix for operator< on reverse_keyt in miniBDD, fixing segfault in ebmc

Author: Daniel Kroening

src/solvers/miniBDD/miniBDD.cpp

@@ -339,15 +339,14 @@ mini_bddt mini_bdd_mgrt::mk(
   }
 }
 
-bool mini_bdd_mgrt::reverse_keyt::operator<(
-  const mini_bdd_mgrt::reverse_keyt &other) const
+bool operator < (const mini_bdd_mgrt::reverse_keyt &x,
+                 const mini_bdd_mgrt::reverse_keyt &y)
 {
-  if(var<other.var || low<other.low)
-    return true;
-  if(var>other.var || low>other.low)
-    return false;
-
-  return high<other.high;
+  if(x.var<y.var) return true;
+  if(x.var>y.var) return false;
+  if(x.low<y.low) return true;
+  if(x.low>y.low) return false;
+  return x.high<y.high;
 }
 
 void mini_bdd_mgrt::DumpTable(std::ostream &out) const

src/solvers/miniBDD/miniBDD.h

@@ -123,10 +123,10 @@ class mini_bdd_mgrt
     unsigned var, low, high;
     reverse_keyt(
       unsigned _var, const mini_bddt &_low, const mini_bddt &_high);
-
-    bool operator<(const reverse_keyt &other) const;
   };
 
+  friend bool operator<(const reverse_keyt &, const reverse_keyt &);
+
   typedef std::map<reverse_keyt, mini_bdd_nodet *> reverse_mapt;
   reverse_mapt reverse_map;