diff --git a/lib/compress.js b/lib/compress.js
index 1d009726..fd24f333 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -2515,7 +2515,7 @@ merge(Compressor.prototype, {
             self.expression = best_of_expression(expression, self.expression);
         }
         if (compressor.option("dead_code")) {
-            var blocks = Object.create(null);
+            var prev_block;
             var decl = [];
             var body = [];
             var default_branch;
@@ -2544,22 +2544,16 @@ merge(Compressor.prototype, {
                 }
                 var case_side_effects = branch instanceof AST_Case && branch.expression.has_side_effects(compressor);
                 if (aborts(branch)) {
-                    var key = make_node(AST_BlockStatement, branch, branch).print_to_string();
-                    var block;
-                    if (!fallthrough && (block = blocks[key])) {
-                        var insert = body.indexOf(block) + 1;
-                        if (insert == body.length || !case_side_effects) {
-                            block.body = [];
-                            body.splice(insert, 0, branch);
-                        } else body.push(branch);
-                    } else body.push(branch);
+                    var block = make_node(AST_BlockStatement, branch, branch).print_to_string();
+                    if (!fallthrough && prev_block === block) body[body.length - 1].body = [];
+                    body.push(branch);
+                    prev_block = block;
                     fallthrough = false;
                 } else {
                     body.push(branch);
+                    prev_block = null;
                     fallthrough = true;
                 }
-                if (case_side_effects) blocks = Object.create(null);
-                if (!fallthrough) blocks[key] = branch;
             }
             for (; i < len && fallthrough; i++) {
                 branch = self.body[i];
diff --git a/test/compress/switch.js b/test/compress/switch.js
index 546e1613..2025d91b 100644
--- a/test/compress/switch.js
+++ b/test/compress/switch.js
@@ -542,11 +542,11 @@ issue_1680_2: {
         var a = 100, b = 10;
         switch (b) {
           case a--:
-          case a:
             break;
           case b:
             var c;
             break;
+          case a:
           case a--:
         }
         console.log(a, b);