diff --git a/lib/compress.js b/lib/compress.js
index 3a361521..469ba980 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -676,7 +676,7 @@ merge(Compressor.prototype, {
                 statements = handle_if_return(statements, compressor);
             }
             if (compressor.sequences_limit > 0) {
-                statements = sequencesize(statements, compressor);
+                sequencesize(statements, compressor);
             }
             if (compressor.option("join_vars")) {
                 join_consecutive_vars(statements, compressor);
@@ -1093,15 +1093,16 @@ merge(Compressor.prototype, {
         };
 
         function sequencesize(statements, compressor) {
-            if (statements.length < 2) return statements;
-            var seq = [], ret = [];
+            if (statements.length < 2) return;
+            var seq = [], n = 0;
             function push_seq() {
                 if (!seq.length) return;
                 var body = make_sequence(seq[0], seq);
-                ret.push(make_node(AST_SimpleStatement, body, { body: body }));
+                statements[n++] = make_node(AST_SimpleStatement, body, { body: body });
                 seq = [];
-            };
-            statements.forEach(function(stat){
+            }
+            for (var i = 0, len = statements.length; i < len; i++) {
+                var stat = statements[i];
                 if (stat instanceof AST_SimpleStatement) {
                     if (seq.length >= compressor.sequences_limit) push_seq();
                     var body = stat.body;
@@ -1109,18 +1110,18 @@ merge(Compressor.prototype, {
                     if (body) merge_sequence(seq, body);
                 } else {
                     push_seq();
-                    ret.push(stat);
+                    statements[n++] = stat;
                 }
-            });
+            }
             push_seq();
-            ret = sequencesize_2(ret, compressor);
-            CHANGED = ret.length != statements.length;
-            return ret;
+            statements.length = n;
+            sequencesize_2(statements, compressor);
+            CHANGED = statements.length != len;
         };
 
         function sequencesize_2(statements, compressor) {
             function cons_seq(right) {
-                ret.pop();
+                n--;
                 var left = prev.body;
                 if (!(left instanceof AST_Sequence)) {
                     left = make_node(AST_Sequence, left, {
@@ -1130,8 +1131,9 @@ merge(Compressor.prototype, {
                 merge_sequence(left.expressions, right);
                 return left.transform(compressor);
             };
-            var ret = [], prev = null;
-            statements.forEach(function(stat){
+            var n = 0, prev;
+            for (var i = 0, len = statements.length; i < len; i++) {
+                var stat = statements[i];
                 if (prev) {
                     if (stat instanceof AST_For) {
                         try {
@@ -1144,7 +1146,7 @@ merge(Compressor.prototype, {
                             }
                             else if (!stat.init) {
                                 stat.init = prev.body.drop_side_effect_free(compressor);
-                                ret.pop();
+                                n--;
                             }
                         } catch(ex) {
                             if (ex !== cons_seq) throw ex;
@@ -1166,11 +1168,11 @@ merge(Compressor.prototype, {
                         stat.expression = cons_seq(stat.expression);
                     }
                 }
-                ret.push(stat);
+                statements[n++] = stat;
                 prev = stat instanceof AST_SimpleStatement ? stat : null;
-            });
-            return ret;
-        };
+            }
+            statements.length = n;
+        }
 
         function join_consecutive_vars(statements, compressor) {
             for (var i = 0, j = -1, len = statements.length; i < len; i++) {
@@ -1197,8 +1199,7 @@ merge(Compressor.prototype, {
             }
             statements.length = j + 1;
         };
-
-    };
+    }
 
     function extract_functions_from_statement_array(statements) {
         var funs = [];