diff --git a/src/ast/rewriter/seq_rewriter.cpp b/src/ast/rewriter/seq_rewriter.cpp
index 7dabfe364..2b9d738c0 100644
--- a/src/ast/rewriter/seq_rewriter.cpp
+++ b/src/ast/rewriter/seq_rewriter.cpp
@@ -3336,6 +3336,15 @@ expr_ref seq_rewriter::mk_regex_union_normalize(expr* r1, expr* r2) {
         result = r1;
     else if (re().is_dot_plus(r2) && re().get_info(r1).min_length > 0)
         result = r2;
+    // (R1 \ R2) U (R2 \ R1) = R1 xor R2
+    else if (false && re().is_intersection(r1, a1, a2) && re().is_intersection(r2, b1, b2) && 
+        is_complement(a1, b2) && is_complement(a2, b1)) {
+        result = re().mk_xor(a1, re().mk_complement(a2));
+    }   
+    else if (false && re().is_intersection(r1, a1, a2) && re().is_intersection(r2, b1, b2) && 
+        is_complement(a1, b1) && is_complement(a2, b2)) {
+        result = re().mk_xor(a1, re().mk_complement(a2));
+    }         
     else {
         // Range ∪ Range: [a,b] ∪ [c,d] = [min(a,c), max(b,d)] when overlapping or adjacent
         unsigned lo1_v = 0, hi1_v = 0, lo2_v = 0, hi2_v = 0;
@@ -3348,17 +3357,7 @@ expr_ref seq_rewriter::mk_regex_union_normalize(expr* r1, expr* r2) {
         else
             result = merge_regex_sets(r1, r2, re().mk_full_seq(r1->get_sort()), test, compose);
     }
-    // (R1 \ R2) U (R2 \ R1) = R1 xor R2
-    else if (false && re().is_intersection(r1, a1, a2) && re().is_intersection(r2, b1, b2) && 
-        is_complement(a1, b2) && is_complement(a2, b1)) {
-        result = re().mk_xor(a1, re().mk_complement(a2));
-    }   
-    else if (false && re().is_intersection(r1, a1, a2) && re().is_intersection(r2, b1, b2) && 
-        is_complement(a1, b1) && is_complement(a2, b2)) {
-        result = re().mk_xor(a1, re().mk_complement(a2));
-    } 
-    else
-        result = merge_regex_sets(r1, r2, re().mk_full_seq(r1->get_sort()), test, compose);
+
     return result;
 }