fix the parameter evaluation order

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

Author: levnach

src/ast/rewriter/bool_rewriter.cpp

@@ -781,9 +781,18 @@ br_status bool_rewriter::mk_eq_core(expr * lhs, expr * rhs, expr_ref & result) {
             m().is_value(t1) && m().is_value(e1) && m().is_value(t2) && m().is_value(e2)) {
             expr_ref_vector args(m());
             args.push_back(m().mk_or(c1, c2, m().mk_eq(e1, e2)));
-            args.push_back(m().mk_or(m().mk_not(c1), m().mk_not(c2), m().mk_eq(t1, t2)));
-            args.push_back(m().mk_or(m().mk_not(c1), c2, m().mk_eq(t1, e2)));
-            args.push_back(m().mk_or(c1, m().mk_not(c2), m().mk_eq(e1, t2)));
+            {
+                auto a = m().mk_not(c1); auto b = m().mk_not(c2);
+                args.push_back(m().mk_or(a, b, m().mk_eq(t1, t2)));
+            }
+            {
+                auto a = m().mk_not(c1);
+                args.push_back(m().mk_or(a, c2, m().mk_eq(t1, e2)));
+            }
+            {
+                auto a = m().mk_not(c2);
+                args.push_back(m().mk_or(c1, a, m().mk_eq(e1, t2)));
+            }
             result = m().mk_and(args);
             return BR_REWRITE_FULL;
         }