fix do{...}while(false)

lib/compress.js

@@ -2404,7 +2404,8 @@ merge(Compressor.prototype, {
                     if (node instanceof AST_LoopControl && tw.loopcontrol_target(node) === self)
                         return has_loop_control = true;
                 });
-                self.walk(tw);
+                var parent = compressor.parent();
+                (parent instanceof AST_LabeledStatement ? parent : self).walk(tw);
                 if (!has_loop_control) return self.body;
             }
         }

test/compress/issue-1833.js

@@ -101,3 +101,20 @@ iife_while: {
         }();
     }
 }
+
+label_do: {
+    options = {
+        evaluate: true,
+        loops: true,
+    }
+    input: {
+        L: do {
+            continue L;
+        } while (0);
+    }
+    expect: {
+        L: do {
+            continue L;
+        } while (0);
+    }
+}