tweak do-while loops

- `do{...}while(false)` => `{...}`
- clean up `AST_While` logic

closes #1452

1 files changed, 6 insertions, 10 deletions

diff --git a/lib/compress.js b/lib/compress.js
index 2ba2982e..ee28ee14 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -1813,8 +1813,14 @@ merge(Compressor.prototype, {
                     extract_declarations_from_unreachable_code(compressor, self.body, a);
                     return make_node(AST_BlockStatement, self, { body: a });
                 }
+            } else {
+                // self instanceof AST_Do
+                return self.body;
             }
         }
+        if (self instanceof AST_While) {
+            return make_node(AST_For, self, self).transform(compressor);
+        }
         return self;
     });
 
@@ -1863,16 +1869,6 @@ merge(Compressor.prototype, {
         }
     };
 
-    OPT(AST_While, function(self, compressor) {
-        if (!compressor.option("loops")) return self;
-        self = AST_DWLoop.prototype.optimize.call(self, compressor);
-        if (self instanceof AST_While) {
-            if_break_in_loop(self, compressor);
-            self = make_node(AST_For, self, self).transform(compressor);
-        }
-        return self;
-    });
-
     OPT(AST_For, function(self, compressor){
         var cond = self.condition;
         if (cond) {