diff --git a/.github/ISSUE_TEMPLATE.md b/.github/ISSUE_TEMPLATE.md
new file mode 100644
index 00000000..31ba69d3
--- /dev/null
+++ b/.github/ISSUE_TEMPLATE.md
@@ -0,0 +1,7 @@
+- Bug report or feature request?
+- `uglify-js` version (`uglifyjs -V`)
+- JavaScript input - ideally as small as possible.
+- The `uglifyjs` CLI command executed or `minify()` options used.
+- An example of JavaScript output produced and/or the error or warning.
+
+Note: the release version of `uglify-js` only supports ES5. Those wishing to minify ES6 should use the experimental [`harmony`](https://github.com/mishoo/UglifyJS2#harmony) branch.
diff --git a/.travis.yml b/.travis.yml
index b91a80e9..b2aef3dc 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,10 +1,13 @@
 language: node_js
 before_install: "npm install -g npm"
 node_js:
-    - "0.12"
     - "0.10"
+    - "0.12"
     - "4"
     - "6"
+    - "7"
+env:
+    - UGLIFYJS_TEST_ALL=1
 matrix:
   fast_finish: true
 sudo: false
diff --git a/README.md b/README.md
index 6dab6ff4..4c47a097 100644
--- a/README.md
+++ b/README.md
@@ -75,8 +75,6 @@ The available options are:
   --support-ie8                 Use this flag to support Internet Explorer 6/7/8.
                                 Equivalent to setting `screw_ie8: false` in `minify()`
                                 for `compress`, `mangle` and `output` options.
-                                Note: `--support-ie8` may generate incorrect code
-                                for `try`/`catch` in ES5 compliant browsers.
   --expr                        Parse a single expression, rather than a
                                 program (for parsing JSON)
   -p, --prefix                  Skip prefix for original filenames that appear
@@ -350,6 +348,9 @@ to set `true`; it's effectively a shortcut for `foo=true`).
   comparison are switching. Compression only works if both `comparisons` and
   `unsafe_comps` are both set to true.
 
+- `unsafe_math` (default: false) -- optimize numerical expressions like
+  `2 * x * 3` into `6 * x`, which may give imprecise floating point results.
+
 - `unsafe_proto` (default: false) -- optimize expressions like
   `Array.prototype.slice.call(a)` into `[].slice.call(a)`
 
@@ -390,11 +391,11 @@ to set `true`; it's effectively a shortcut for `foo=true`).
 - `cascade` -- small optimization for sequences, transform `x, x` into `x`
   and `x = something(), x` into `x = something()`
 
-- `collapse_vars` -- default `false`. Collapse single-use `var` and `const`
-  definitions when possible.
+- `collapse_vars` -- Collapse single-use `var` and `const` definitions
+  when possible.
 
-- `reduce_vars` -- default `false`. Improve optimization on variables assigned
-  with and used as constant values.
+- `reduce_vars` -- Improve optimization on variables assigned with and
+  used as constant values.
 
 - `warnings` -- display warnings when dropping unreachable code or unused
   declarations etc.
@@ -426,6 +427,10 @@ to set `true`; it's effectively a shortcut for `foo=true`).
 - `drop_error` -- default `false`.  Pass `true` to discard description
   of Error() calls.
 
+- `expression` -- default `false`.  Pass `true` to preserve completion values
+  from terminal statements without `return`, e.g. in bookmarklets.
+
+
 - `keep_fargs` -- default `true`.  Prevents the
   compressor from discarding unused function arguments.  You need this
   for code which relies on `Function.length`.
diff --git a/bin/uglifyjs b/bin/uglifyjs
index 367d66e2..e39a4b4b 100755
--- a/bin/uglifyjs
+++ b/bin/uglifyjs
@@ -8,7 +8,6 @@ var sys = require("util");
 var yargs = require("yargs");
 var fs = require("fs");
 var path = require("path");
-var async = require("async");
 var acorn;
 var screw_ie8 = true;
 var ARGS = yargs
@@ -27,7 +26,7 @@ mangling you need to use `-c` and `-m`.\
     .describe("source-map-include-sources", "Pass this flag if you want to include the content of source files in the source map as sourcesContent property.")
     .describe("in-source-map", "Input source map, useful if you're compressing JS that was generated from some other original code.")
     .describe("screw-ie8", "Do not support Internet Explorer 6/7/8. This flag is enabled by default.")
-    .describe("support-ie8", "Support non-standard Internet Explorer 6/7/8 javascript. Note: may generate incorrect code for try/catch in ES5 compliant browsers.")
+    .describe("support-ie8", "Support non-standard Internet Explorer 6/7/8 javascript.")
     .describe("expr", "Parse a single expression, rather than a program (for parsing JSON)")
     .describe("p", "Skip prefix for original filenames that appear in source maps. \
 For example -p 3 will drop 3 directories from file names and ensure they are relative paths. \
@@ -319,8 +318,11 @@ var STATS = {};
 var TOPLEVEL = null;
 var P_RELATIVE = ARGS.p && ARGS.p == "relative";
 var SOURCES_CONTENT = {};
+var index = 0;
 
-async.eachLimit(files, 1, function (file, cb) {
+!function cb() {
+    if (index == files.length) return done();
+    var file = files[index++];
     read_whole_file(file, function (err, code) {
         if (err) {
             print_error("ERROR: can't read file: " + file);
@@ -388,7 +390,9 @@ async.eachLimit(files, 1, function (file, cb) {
         });
         cb();
     });
-}, function () {
+}();
+
+function done() {
     var OUTPUT_FILE = ARGS.o;
 
     var SOURCE_MAP = (ARGS.source_map || ARGS.source_map_inline) ? UglifyJS.SourceMap({
@@ -537,7 +541,7 @@ async.eachLimit(files, 1, function (file, cb) {
             }));
         }
     }
-});
+}
 
 /* -----[ functions ]----- */
 
diff --git a/lib/ast.js b/lib/ast.js
index f3df78fe..092a9590 100644
--- a/lib/ast.js
+++ b/lib/ast.js
@@ -91,9 +91,20 @@ var AST_Token = DEFNODE("Token", "type value line col pos endline endcol endpos
 }, null);
 
 var AST_Node = DEFNODE("Node", "start end", {
-    clone: function() {
+    _clone: function(deep) {
+        if (deep) {
+            var self = this.clone();
+            return self.transform(new TreeTransformer(function(node) {
+                if (node !== self) {
+                    return node.clone(true);
+                }
+            }));
+        }
         return new this.CTOR(this);
     },
+    clone: function(deep) {
+        return this._clone(deep);
+    },
     $documentation: "Base class of all AST nodes",
     $propdoc: {
         start: "[AST_Token] The first token of this node",
@@ -199,6 +210,20 @@ var AST_LabeledStatement = DEFNODE("LabeledStatement", "label", {
             this.label._walk(visitor);
             this.body._walk(visitor);
         });
+    },
+    clone: function(deep) {
+        var node = this._clone(deep);
+        if (deep) {
+            var refs = node.label.references;
+            var label = this.label;
+            node.walk(new TreeWalker(function(node) {
+                if (node instanceof AST_LoopControl
+                    && node.label && node.label.thedef === label) {
+                    refs.push(node);
+                }
+            }));
+        }
+        return node;
     }
 }, AST_StatementWithBody);
 
@@ -812,9 +837,6 @@ var AST_SymbolAccessor = DEFNODE("SymbolAccessor", null, {
 
 var AST_SymbolDeclaration = DEFNODE("SymbolDeclaration", "init", {
     $documentation: "A declaration symbol (symbol in var/const, function name or argument, symbol in catch)",
-    $propdoc: {
-        init: "[AST_Node*/S] array of initializers for this declaration."
-    }
 }, AST_Symbol);
 
 var AST_SymbolVar = DEFNODE("SymbolVar", null, {
@@ -962,8 +984,8 @@ TreeWalker.prototype = {
     push: function (node) {
         if (node instanceof AST_Lambda) {
             this.directives = Object.create(this.directives);
-        } else if (node instanceof AST_Directive) {
-            this.directives[node.value] = this.directives[node.value] ? "up" : true;
+        } else if (node instanceof AST_Directive && !this.directives[node.value]) {
+            this.directives[node.value] = node;
         }
         this.stack.push(node);
     },
@@ -991,7 +1013,7 @@ TreeWalker.prototype = {
             for (var i = 0; i < node.body.length; ++i) {
                 var st = node.body[i];
                 if (!(st instanceof AST_Directive)) break;
-                if (st.value == type) return true;
+                if (st.value == type) return st;
             }
         }
     },
diff --git a/lib/compress.js b/lib/compress.js
index c27b2b96..03410eb2 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -54,6 +54,7 @@ function Compressor(options, false_by_default) {
         drop_debugger : !false_by_default,
         unsafe        : false,
         unsafe_comps  : false,
+        unsafe_math   : false,
         unsafe_proto  : false,
         conditionals  : !false_by_default,
         comparisons   : !false_by_default,
@@ -80,6 +81,7 @@ function Compressor(options, false_by_default) {
         drop_console  : false,
         drop_error    : false,
         angular       : false,
+        expression    : false,
         warnings      : true,
         global_defs   : {},
         passes        : 1,
@@ -116,12 +118,18 @@ Compressor.prototype = new TreeTransformer;
 merge(Compressor.prototype, {
     option: function(key) { return this.options[key] },
     compress: function(node) {
+        if (this.option("expression")) {
+            node = node.process_expression(true);
+        }
         var passes = +this.options.passes || 1;
         for (var pass = 0; pass < passes && pass < 3; ++pass) {
             if (pass > 0 || this.option("reduce_vars"))
                 node.reset_opt_flags(this, true);
             node = node.transform(this);
         }
+        if (this.option("expression")) {
+            node = node.process_expression(false);
+        }
         return node;
     },
     warn: function(text, props) {
@@ -178,11 +186,56 @@ merge(Compressor.prototype, {
         return this.print_to_string() == node.print_to_string();
     });
 
+    AST_Node.DEFMETHOD("process_expression", function(insert) {
+        var self = this;
+        var tt = new TreeTransformer(function(node) {
+            if (insert && node instanceof AST_SimpleStatement) {
+                return make_node(AST_Return, node, {
+                    value: node.body
+                });
+            }
+            if (!insert && node instanceof AST_Return) {
+                return make_node(AST_SimpleStatement, node, {
+                    body: node.value || make_node(AST_Undefined, node)
+                });
+            }
+            if (node instanceof AST_Lambda && node !== self) {
+                return node;
+            }
+            if (node instanceof AST_Block) {
+                var index = node.body.length - 1;
+                if (index >= 0) {
+                    node.body[index] = node.body[index].transform(tt);
+                }
+            }
+            if (node instanceof AST_If) {
+                node.body = node.body.transform(tt);
+                if (node.alternative) {
+                    node.alternative = node.alternative.transform(tt);
+                }
+            }
+            if (node instanceof AST_With) {
+                node.body = node.body.transform(tt);
+            }
+            return node;
+        });
+        return self.transform(tt);
+    });
+
     AST_Node.DEFMETHOD("reset_opt_flags", function(compressor, rescan){
         var reduce_vars = rescan && compressor.option("reduce_vars");
+        var toplevel = compressor.option("toplevel");
+        var ie8 = !compressor.option("screw_ie8");
         var safe_ids = [];
         push();
-        var tw = new TreeWalker(function(node){
+        var suppressor = new TreeWalker(function(node) {
+            if (node instanceof AST_Symbol) {
+                var d = node.definition();
+                if (node instanceof AST_SymbolRef) d.references.push(node);
+                d.fixed = false;
+            }
+        });
+        var tw = new TreeWalker(function(node, descend){
             if (!(node instanceof AST_Directive || node instanceof AST_Constant)) {
                 node._squeezed = false;
                 node._optimized = false;
@@ -193,10 +246,14 @@ merge(Compressor.prototype, {
                 if (node instanceof AST_SymbolRef) {
                     var d = node.definition();
                     d.references.push(node);
-                    if (!d.fixed || isModified(node, 0) || !is_safe(d)) {
+                    if (!d.fixed || !is_safe(d)
+                        || is_modified(node, 0, d.fixed instanceof AST_Lambda)) {
                         d.fixed = false;
                     }
                 }
+                if (ie8 && node instanceof AST_SymbolCatch) {
+                    node.definition().fixed = false;
+                }
                 if (node instanceof AST_VarDef) {
                     var d = node.name.definition();
                     if (d.fixed === undefined) {
@@ -206,6 +263,21 @@ merge(Compressor.prototype, {
                         d.fixed = false;
                     }
                 }
+                if (node instanceof AST_Defun) {
+                    var d = node.name.definition();
+                    if (!toplevel && d.global || is_safe(d)) {
+                        d.fixed = false;
+                    } else {
+                        d.fixed = node;
+                        mark_as_safe(d);
+                    }
+                    var save_ids = safe_ids;
+                    safe_ids = [];
+                    push();
+                    descend();
+                    safe_ids = save_ids;
+                    return true;
+                }
                 var iife;
                 if (node instanceof AST_Function
                     && (iife = tw.parent()) instanceof AST_Call
@@ -244,15 +316,19 @@ merge(Compressor.prototype, {
                     return true;
                 }
                 if (node instanceof AST_ForIn) {
-                    if (node.init instanceof AST_SymbolRef) {
-                        node.init.definition().fixed = false;
-                    }
+                    node.init.walk(suppressor);
                     node.object.walk(tw);
                     push();
                     node.body.walk(tw);
                     pop();
                     return true;
                 }
+                if (node instanceof AST_Catch) {
+                    push();
+                    descend();
+                    pop();
+                    return true;
+                }
             }
         });
         this.walk(tw);
@@ -276,18 +352,22 @@ merge(Compressor.prototype, {
         }
 
         function reset_def(def) {
-            def.fixed = undefined;
+            if (toplevel || !def.global || def.orig[0] instanceof AST_SymbolConst) {
+                def.fixed = undefined;
+            } else {
+                def.fixed = false;
+            }
             def.references = [];
             def.should_replace = undefined;
         }
 
-        function isModified(node, level) {
+        function is_modified(node, level, func) {
             var parent = tw.parent(level);
             if (isLHS(node, parent)
-                || parent instanceof AST_Call && parent.expression === node) {
+                || !func && parent instanceof AST_Call && parent.expression === node) {
                 return true;
             } else if (parent instanceof AST_PropAccess && parent.expression === node) {
-                return isModified(parent, level + 1);
+                return !func && is_modified(parent, level + 1);
             }
         }
     });
@@ -477,8 +557,13 @@ merge(Compressor.prototype, {
                     // Constant single use vars can be replaced in any scope.
                     if (var_decl.value.is_constant()) {
                         var ctt = new TreeTransformer(function(node) {
+                            var parent = ctt.parent();
+                            if (parent instanceof AST_IterationStatement
+                                && (parent.condition === node || parent.init === node)) {
+                                return node;
+                            }
                             if (node === ref)
-                                return replace_var(node, ctt.parent(), true);
+                                return replace_var(node, parent, true);
                         });
                         stat.transform(ctt);
                         continue;
@@ -547,10 +632,7 @@ merge(Compressor.prototype, {
             return statements;
 
             function is_lvalue(node, parent) {
-                return node instanceof AST_SymbolRef && (
-                    (parent instanceof AST_Assign && node === parent.left)
-                    || (parent instanceof AST_Unary && parent.expression === node
-                        && (parent.operator == "++" || parent.operator == "--")));
+                return node instanceof AST_SymbolRef && isLHS(node, parent);
             }
             function replace_var(node, parent, is_constant) {
                 if (is_lvalue(node, parent)) return node;
@@ -567,7 +649,7 @@ merge(Compressor.prototype, {
                 // Further optimize statement after substitution.
                 stat.reset_opt_flags(compressor);
 
-                compressor.warn("Replacing " + (is_constant ? "constant" : "variable") +
+                compressor.warn("Collapsing " + (is_constant ? "constant" : "variable") +
                     " " + var_name + " [{file}:{line},{col}]", node.start);
                 CHANGED = true;
                 return value;
@@ -715,7 +797,7 @@ merge(Compressor.prototype, {
                             CHANGED = true;
                             stat = stat.clone();
                             stat.alternative = ret[0] || make_node(AST_Return, stat, {
-                                value: make_node(AST_Undefined, stat)
+                                value: null
                             });
                             ret[0] = stat.transform(compressor);
                             continue loop;
@@ -748,7 +830,7 @@ merge(Compressor.prototype, {
                             && !stat.alternative) {
                             CHANGED = true;
                             ret.push(make_node(AST_Return, ret[0], {
-                                value: make_node(AST_Undefined, ret[0])
+                                value: null
                             }).transform(compressor));
                             ret.unshift(stat);
                             continue loop;
@@ -1005,6 +1087,10 @@ merge(Compressor.prototype, {
         }));
     };
 
+    function is_undefined(node) {
+        return node instanceof AST_Undefined || node.is_undefined;
+    }
+
     /* -----[ boolean/negation helpers ]----- */
 
     // methods to determine whether an expression has a boolean result type
@@ -1035,6 +1121,34 @@ merge(Compressor.prototype, {
         node.DEFMETHOD("is_boolean", func);
     });
 
+    // methods to determine if an expression has a numeric result type
+    (function (def){
+        def(AST_Node, return_false);
+        def(AST_Number, return_true);
+        var unary = makePredicate("+ - ~ ++ --");
+        def(AST_Unary, function(){
+            return unary(this.operator);
+        });
+        var binary = makePredicate("- * / % & | ^ << >> >>>");
+        def(AST_Binary, function(compressor){
+            return binary(this.operator) || this.operator == "+"
+                && this.left.is_number(compressor)
+                && this.right.is_number(compressor);
+        });
+        var assign = makePredicate("-= *= /= %= &= |= ^= <<= >>= >>>=");
+        def(AST_Assign, function(compressor){
+            return assign(this.operator) || this.right.is_number(compressor);
+        });
+        def(AST_Seq, function(compressor){
+            return this.cdr.is_number(compressor);
+        });
+        def(AST_Conditional, function(compressor){
+            return this.consequent.is_number(compressor) && this.alternative.is_number(compressor);
+        });
+    })(function(node, func){
+        node.DEFMETHOD("is_number", func);
+    });
+
     // methods to determine if an expression has a string result type
     (function (def){
         def(AST_Node, return_false);
@@ -1060,7 +1174,7 @@ merge(Compressor.prototype, {
     });
 
     function isLHS(node, parent) {
-        return parent instanceof AST_Unary && (parent.operator === "++" || parent.operator === "--")
+        return parent instanceof AST_Unary && (parent.operator == "++" || parent.operator == "--")
             || parent instanceof AST_Assign && parent.left === node;
     }
 
@@ -1210,14 +1324,7 @@ merge(Compressor.prototype, {
         def(AST_Statement, function(){
             throw new Error(string_template("Cannot evaluate a statement [{file}:{line},{col}]", this.start));
         });
-        // XXX: AST_Accessor and AST_Function both inherit from AST_Scope,
-        // which itself inherits from AST_Statement; however, they aren't
-        // really statements.  This could bite in other places too. :-(
-        // Wish JS had multiple inheritance.
-        def(AST_Accessor, function(){
-            throw def;
-        });
-        def(AST_Function, function(){
+        def(AST_Lambda, function(){
             throw def;
         });
         function ev(node, compressor) {
@@ -1734,6 +1841,7 @@ merge(Compressor.prototype, {
                     }
                     if (drop_vars && node instanceof AST_Definitions && !(tt.parent() instanceof AST_ForIn)) {
                         var def = node.definitions.filter(function(def){
+                            if (def.value) def.value = def.value.transform(tt);
                             if (def.name.definition().id in in_use_ids) return true;
                             var w = {
                                 name : def.name.name,
@@ -1794,14 +1902,17 @@ merge(Compressor.prototype, {
                         }
                         return node;
                     }
-                    if (drop_vars && assign_as_unused
-                        && node instanceof AST_Assign
-                        && node.operator == "="
-                        && node.left instanceof AST_SymbolRef) {
-                        var def = node.left.definition();
-                        if (!(def.id in in_use_ids) && self.variables.get(def.name) === def) {
-                            return node.right;
+                    if (drop_vars && assign_as_unused) {
+                        var n = node;
+                        while (n instanceof AST_Assign
+                            && n.operator == "="
+                            && n.left instanceof AST_SymbolRef) {
+                            var def = n.left.definition();
+                            if (def.id in in_use_ids
+                                || self.variables.get(def.name) !== def) break;
+                            n = n.right;
                         }
+                        if (n !== node) return n;
                     }
                     if (node instanceof AST_For) {
                         descend(node, this);
@@ -1990,7 +2101,15 @@ merge(Compressor.prototype, {
         def(AST_Constant, return_null);
         def(AST_This, return_null);
         def(AST_Call, function(compressor, first_in_statement){
-            if (!this.has_pure_annotation(compressor) && compressor.pure_funcs(this)) return this;
+            if (!this.has_pure_annotation(compressor) && compressor.pure_funcs(this)) {
+                if (this.expression instanceof AST_Function
+                    && (!this.expression.name || !this.expression.name.definition().references.length)) {
+                    var node = this.clone();
+                    node.expression = node.expression.process_expression(false);
+                    return node;
+                }
+                return this;
+            }
             if (this.pure) {
                 compressor.warn("Dropping __PURE__ call [{file}:{line},{col}]", this.start);
                 this.pure.value = this.pure.value.replace(/[@#]__PURE__/g, ' ');
@@ -2133,7 +2252,7 @@ merge(Compressor.prototype, {
                 }
             } else {
                 // self instanceof AST_Do
-                return self.body;
+                return self;
             }
         }
         if (self instanceof AST_While) {
@@ -2314,8 +2433,8 @@ merge(Compressor.prototype, {
             return make_node(self.body.CTOR, self, {
                 value: make_node(AST_Conditional, self, {
                     condition   : self.condition,
-                    consequent  : self.body.value || make_node(AST_Undefined, self.body).optimize(compressor),
-                    alternative : self.alternative.value || make_node(AST_Undefined, self.alternative).optimize(compressor)
+                    consequent  : self.body.value || make_node(AST_Undefined, self.body),
+                    alternative : self.alternative.value || make_node(AST_Undefined, self.alternative)
                 })
             }).transform(compressor);
         }
@@ -2482,12 +2601,28 @@ merge(Compressor.prototype, {
     });
 
     OPT(AST_Call, function(self, compressor){
+        var exp = self.expression;
+        if (compressor.option("reduce_vars")
+            && exp instanceof AST_SymbolRef) {
+            var def = exp.definition();
+            if (def.fixed instanceof AST_Defun) {
+                def.fixed = make_node(AST_Function, def.fixed, def.fixed).clone(true);
+            }
+            if (def.fixed instanceof AST_Function) {
+                exp = def.fixed;
+                if (compressor.option("unused")
+                    && def.references.length == 1
+                    && compressor.find_parent(AST_Scope) === def.scope) {
+                    self.expression = exp;
+                }
+            }
+        }
         if (compressor.option("unused")
-            && self.expression instanceof AST_Function
-            && !self.expression.uses_arguments
-            && !self.expression.uses_eval
-            && self.args.length > self.expression.argnames.length) {
-            var end = self.expression.argnames.length;
+            && exp instanceof AST_Function
+            && !exp.uses_arguments
+            && !exp.uses_eval
+            && self.args.length > exp.argnames.length) {
+            var end = exp.argnames.length;
             for (var i = end, len = self.args.length; i < len; i++) {
                 var node = self.args[i].drop_side_effect_free(compressor);
                 if (node) {
@@ -2497,7 +2632,6 @@ merge(Compressor.prototype, {
             self.args.length = end;
         }
         if (compressor.option("unsafe")) {
-            var exp = self.expression;
             if (exp instanceof AST_SymbolRef && exp.undeclared()) {
                 switch (exp.name) {
                   case "Array":
@@ -2687,16 +2821,24 @@ merge(Compressor.prototype, {
                    self.args = [];
                 }
         }
-        if (compressor.option("side_effects")) {
-            if (self.expression instanceof AST_Function
-                && self.args.length == 0
-                && !AST_Block.prototype.has_side_effects.call(self.expression, compressor)) {
-                return make_node(AST_Undefined, self).transform(compressor);
+        if (exp instanceof AST_Function) {
+            if (exp.body[0] instanceof AST_Return) {
+                var value = exp.body[0].value;
+                if (!value || value.is_constant()) {
+                    var args = self.args.concat(value || make_node(AST_Undefined, self));
+                    return AST_Seq.from_array(args).transform(compressor);
+                }
+            }
+            if (compressor.option("side_effects")) {
+                if (!AST_Block.prototype.has_side_effects.call(exp, compressor)) {
+                    var args = self.args.concat(make_node(AST_Undefined, self));
+                    return AST_Seq.from_array(args).transform(compressor);
+                }
             }
         }
         if (compressor.option("drop_console")) {
-            if (self.expression instanceof AST_PropAccess) {
-                var name = self.expression.expression;
+            if (exp instanceof AST_PropAccess) {
+                var name = exp.expression;
                 while (name.expression) {
                     name = name.expression;
                 }
@@ -2707,12 +2849,6 @@ merge(Compressor.prototype, {
                 }
             }
         }
-        if (self.args.length == 0
-            && self.expression instanceof AST_Function
-            && self.expression.body[0] instanceof AST_Return
-            && self.expression.body[0].value.is_constant()) {
-            return self.expression.body[0].value;
-        }
         if (compressor.option("negate_iife")
             && compressor.parent() instanceof AST_SimpleStatement
             && is_iife_call(self)) {
@@ -2767,23 +2903,41 @@ merge(Compressor.prototype, {
         self.car = self.car.drop_side_effect_free(compressor, first_in_statement(compressor));
         if (!self.car) return maintain_this_binding(compressor.parent(), self, self.cdr);
         if (compressor.option("cascade")) {
+            var left;
             if (self.car instanceof AST_Assign
                 && !self.car.left.has_side_effects(compressor)) {
-                if (self.car.left.equivalent_to(self.cdr)) {
-                    return self.car;
-                }
-                if (self.cdr instanceof AST_Call
-                    && self.cdr.expression.equivalent_to(self.car.left)) {
-                    self.cdr.expression = self.car;
-                    return self.cdr;
-                }
+                left = self.car.left;
+            } else if (self.car instanceof AST_Unary
+                && (self.car.operator == "++" || self.car.operator == "--")) {
+                left = self.car.expression;
             }
-            if (!self.car.has_side_effects(compressor)
-                && self.car.equivalent_to(self.cdr)) {
-                return self.car;
+            if (left) {
+                var parent, field;
+                var cdr = self.cdr;
+                while (true) {
+                    if (cdr.equivalent_to(left)) {
+                        var car = self.car instanceof AST_UnaryPostfix ? make_node(AST_UnaryPrefix, self.car, {
+                            operator: self.car.operator,
+                            expression: left
+                        }) : self.car;
+                        if (parent) {
+                            parent[field] = car;
+                            return self.cdr;
+                        }
+                        return car;
+                    }
+                    if (cdr instanceof AST_Binary && !(cdr instanceof AST_Assign)) {
+                        field = cdr.left.is_constant() ? "right" : "left";
+                    } else if (cdr instanceof AST_Call
+                        || cdr instanceof AST_Unary && cdr.operator != "++" && cdr.operator != "--") {
+                        field = "expression";
+                    } else break;
+                    parent = cdr;
+                    cdr = cdr[field];
+                }
             }
         }
-        if (self.cdr instanceof AST_Undefined) {
+        if (is_undefined(self.cdr)) {
             return make_node(AST_UnaryPrefix, self, {
                 operator   : "void",
                 expression : self.car
@@ -2822,7 +2976,7 @@ merge(Compressor.prototype, {
                 self.expression = e;
                 return self;
             } else {
-                return make_node(AST_Undefined, self);
+                return make_node(AST_Undefined, self).transform(compressor);
             }
         }
         if (compressor.option("booleans") && compressor.in_boolean_context()) {
@@ -2895,8 +3049,14 @@ merge(Compressor.prototype, {
                 right: rhs[0]
             }).optimize(compressor);
         }
-        function reverse(op, force) {
-            if (force || !(self.left.has_side_effects(compressor) || self.right.has_side_effects(compressor))) {
+        function reversible() {
+            return self.left instanceof AST_Constant
+                || self.right instanceof AST_Constant
+                || !self.left.has_side_effects(compressor)
+                    && !self.right.has_side_effects(compressor);
+        }
+        function reverse(op) {
+            if (reversible()) {
                 if (op) self.operator = op;
                 var tmp = self.left;
                 self.left = self.right;
@@ -2912,7 +3072,7 @@ merge(Compressor.prototype, {
 
                 if (!(self.left instanceof AST_Binary
                       && PRECEDENCE[self.left.operator] >= PRECEDENCE[self.operator])) {
-                    reverse(null, true);
+                    reverse();
                 }
             }
             if (/^[!=]==?$/.test(self.operator)) {
@@ -2947,6 +3107,7 @@ merge(Compressor.prototype, {
           case "===":
           case "!==":
             if ((self.left.is_string(compressor) && self.right.is_string(compressor)) ||
+                (self.left.is_number(compressor) && self.right.is_number(compressor)) ||
                 (self.left.is_boolean() && self.right.is_boolean())) {
                 self.operator = self.operator.substr(0, 2);
             }
@@ -3084,7 +3245,10 @@ merge(Compressor.prototype, {
                 }
                 break;
             }
-            if (self.operator == "+") {
+            var associative = true;
+            switch (self.operator) {
+              case "+":
+                // "foo" + ("bar" + x) => "foobar" + x
                 if (self.left instanceof AST_Constant
                     && self.right instanceof AST_Binary
                     && self.right.operator == "+"
@@ -3092,7 +3256,7 @@ merge(Compressor.prototype, {
                     && self.right.is_string(compressor)) {
                     self = make_node(AST_Binary, self, {
                         operator: "+",
-                        left: make_node(AST_String, null, {
+                        left: make_node(AST_String, self.left, {
                             value: "" + self.left.getValue() + self.right.left.getValue(),
                             start: self.left.start,
                             end: self.right.left.end
@@ -3100,6 +3264,7 @@ merge(Compressor.prototype, {
                         right: self.right.right
                     });
                 }
+                // (x + "foo") + "bar" => x + "foobar"
                 if (self.right instanceof AST_Constant
                     && self.left instanceof AST_Binary
                     && self.left.operator == "+"
@@ -3108,13 +3273,14 @@ merge(Compressor.prototype, {
                     self = make_node(AST_Binary, self, {
                         operator: "+",
                         left: self.left.left,
-                        right: make_node(AST_String, null, {
+                        right: make_node(AST_String, self.right, {
                             value: "" + self.left.right.getValue() + self.right.getValue(),
                             start: self.left.right.start,
                             end: self.right.end
                         })
                     });
                 }
+                // (x + "foo") + ("bar" + y) => (x + "foobar") + y
                 if (self.left instanceof AST_Binary
                     && self.left.operator == "+"
                     && self.left.is_string(compressor)
@@ -3128,7 +3294,7 @@ merge(Compressor.prototype, {
                         left: make_node(AST_Binary, self.left, {
                             operator: "+",
                             left: self.left.left,
-                            right: make_node(AST_String, null, {
+                            right: make_node(AST_String, self.left.right, {
                                 value: "" + self.left.right.getValue() + self.right.left.getValue(),
                                 start: self.left.right.start,
                                 end: self.right.left.end
@@ -3137,6 +3303,122 @@ merge(Compressor.prototype, {
                         right: self.right.right
                     });
                 }
+                // a + -b => a - b
+                if (self.right instanceof AST_UnaryPrefix
+                    && self.right.operator == "-"
+                    && self.left.is_number(compressor)) {
+                    self = make_node(AST_Binary, self, {
+                        operator: "-",
+                        left: self.left,
+                        right: self.right.expression
+                    });
+                }
+                // -a + b => b - a
+                if (self.left instanceof AST_UnaryPrefix
+                    && self.left.operator == "-"
+                    && reversible()
+                    && self.right.is_number(compressor)) {
+                    self = make_node(AST_Binary, self, {
+                        operator: "-",
+                        left: self.right,
+                        right: self.left.expression
+                    });
+                }
+              case "*":
+                associative = compressor.option("unsafe_math");
+              case "&":
+              case "|":
+              case "^":
+                // a + +b => +b + a
+                if (self.left.is_number(compressor)
+                    && self.right.is_number(compressor)
+                    && reversible()
+                    && !(self.left instanceof AST_Binary
+                        && self.left.operator != self.operator
+                        && PRECEDENCE[self.left.operator] >= PRECEDENCE[self.operator])) {
+                    var reversed = make_node(AST_Binary, self, {
+                        operator: self.operator,
+                        left: self.right,
+                        right: self.left
+                    });
+                    if (self.right instanceof AST_Constant
+                        && !(self.left instanceof AST_Constant)) {
+                        self = best_of(reversed, self);
+                    } else {
+                        self = best_of(self, reversed);
+                    }
+                }
+                if (associative && self.is_number(compressor)) {
+                    // a + (b + c) => (a + b) + c
+                    if (self.right instanceof AST_Binary
+                        && self.right.operator == self.operator) {
+                        self = make_node(AST_Binary, self, {
+                            operator: self.operator,
+                            left: make_node(AST_Binary, self.left, {
+                                operator: self.operator,
+                                left: self.left,
+                                right: self.right.left,
+                                start: self.left.start,
+                                end: self.right.left.end
+                            }),
+                            right: self.right.right
+                        });
+                    }
+                    // (n + 2) + 3 => 5 + n
+                    // (2 * n) * 3 => 6 + n
+                    if (self.right instanceof AST_Constant
+                        && self.left instanceof AST_Binary
+                        && self.left.operator == self.operator) {
+                        if (self.left.left instanceof AST_Constant) {
+                            self = make_node(AST_Binary, self, {
+                                operator: self.operator,
+                                left: make_node(AST_Binary, self.left, {
+                                    operator: self.operator,
+                                    left: self.left.left,
+                                    right: self.right,
+                                    start: self.left.left.start,
+                                    end: self.right.end
+                                }),
+                                right: self.left.right
+                            });
+                        } else if (self.left.right instanceof AST_Constant) {
+                            self = make_node(AST_Binary, self, {
+                                operator: self.operator,
+                                left: make_node(AST_Binary, self.left, {
+                                    operator: self.operator,
+                                    left: self.left.right,
+                                    right: self.right,
+                                    start: self.left.right.start,
+                                    end: self.right.end
+                                }),
+                                right: self.left.left
+                            });
+                        }
+                    }
+                    // (a | 1) | (2 | d) => (3 | a) | b
+                    if (self.left instanceof AST_Binary
+                        && self.left.operator == self.operator
+                        && self.left.right instanceof AST_Constant
+                        && self.right instanceof AST_Binary
+                        && self.right.operator == self.operator
+                        && self.right.left instanceof AST_Constant) {
+                        self = make_node(AST_Binary, self, {
+                            operator: self.operator,
+                            left: make_node(AST_Binary, self.left, {
+                                operator: self.operator,
+                                left: make_node(AST_Binary, self.left.left, {
+                                    operator: self.operator,
+                                    left: self.left.right,
+                                    right: self.right.left,
+                                    start: self.left.right.start,
+                                    end: self.right.left.end
+                                }),
+                                right: self.left.left
+                            }),
+                            right: self.right.right
+                        });
+                    }
+                }
             }
         }
         // x && (y && z)  ==>  x && y && z
@@ -3169,11 +3451,13 @@ merge(Compressor.prototype, {
             return def;
         }
         // testing against !self.scope.uses_with first is an optimization
-        if (self.undeclared() && !isLHS(self, compressor.parent())
+        if (compressor.option("screw_ie8")
+            && self.undeclared()
+            && !isLHS(self, compressor.parent())
             && (!self.scope.uses_with || !compressor.find_parent(AST_With))) {
             switch (self.name) {
               case "undefined":
-                return make_node(AST_Undefined, self);
+                return make_node(AST_Undefined, self).transform(compressor);
               case "NaN":
                 return make_node(AST_NaN, self).transform(compressor);
               case "Infinity":
@@ -3216,11 +3500,13 @@ merge(Compressor.prototype, {
             var scope = compressor.find_parent(AST_Scope);
             var undef = scope.find_variable("undefined");
             if (undef) {
-                return make_node(AST_SymbolRef, self, {
+                var ref = make_node(AST_SymbolRef, self, {
                     name   : "undefined",
                     scope  : scope,
                     thedef : undef
                 });
+                ref.is_undefined = true;
+                return ref;
             }
         }
         return self;
@@ -3507,7 +3793,7 @@ merge(Compressor.prototype, {
     OPT(AST_RegExp, literals_in_boolean_context);
 
     OPT(AST_Return, function(self, compressor){
-        if (self.value instanceof AST_Undefined) {
+        if (self.value && is_undefined(self.value)) {
             self.value = null;
         }
         return self;
diff --git a/lib/output.js b/lib/output.js
index 4a0a1e0e..767abd4d 100644
--- a/lib/output.js
+++ b/lib/output.js
@@ -46,17 +46,8 @@
 var EXPECT_DIRECTIVE = /^$|[;{][\s\n]*$/;
 
 function is_some_comments(comment) {
-    var text = comment.value;
-    var type = comment.type;
-    if (type == "comment2") {
-        // multiline comment
-        return /@preserve|@license|@cc_on/i.test(text);
-    }
-    return type == "comment5";
-}
-
-function is_comment5(comment) {
-    return comment.type == "comment5";
+    // multiline comment
+    return comment.type == "comment2" && /@preserve|@license|@cc_on/i.test(comment.value);
 }
 
 function OutputStream(options) {
@@ -86,7 +77,7 @@ function OutputStream(options) {
     }, true);
 
     // Convert comment option to RegExp if neccessary and set up comments filter
-    var comment_filter = options.shebang ? is_comment5 : return_false; // Default case, throw all comments away except shebangs
+    var comment_filter = return_false; // Default case, throw all comments away
     if (options.comments) {
         var comments = options.comments;
         if (typeof options.comments === "string" && /^\/.*\/[a-zA-Z]*$/.test(options.comments)) {
@@ -98,12 +89,12 @@ function OutputStream(options) {
         }
         if (comments instanceof RegExp) {
             comment_filter = function(comment) {
-                return comment.type == "comment5" || comments.test(comment.value);
+                return comment.type != "comment5" && comments.test(comment.value);
             };
         }
         else if (typeof comments === "function") {
             comment_filter = function(comment) {
-                return comment.type == "comment5" || comments(this, comment);
+                return comment.type != "comment5" && comments(this, comment);
             };
         }
         else if (comments === "some") {
@@ -400,10 +391,6 @@ function OutputStream(options) {
         return OUTPUT;
     };
 
-    if (options.preamble) {
-        print(options.preamble.replace(/\r\n?|[\n\u2028\u2029]|\s*$/g, "\n"));
-    }
-
     var stack = [];
     return {
         get             : get,
@@ -523,6 +510,17 @@ function OutputStream(options) {
                 }));
             }
 
+            if (comments.length > 0 && output.pos() == 0) {
+                if (output.option("shebang") && comments[0].type == "comment5") {
+                    output.print("#!" + comments.shift().value + "\n");
+                    output.indent();
+                }
+                var preamble = output.option("preamble");
+                if (preamble) {
+                    output.print(preamble.replace(/\r\n?|[\n\u2028\u2029]|\s*$/g, "\n"));
+                }
+            }
+
             comments = comments.filter(output.comment_filter, self);
 
             // Keep single line comments after nlb, after nlb
@@ -547,10 +545,6 @@ function OutputStream(options) {
                         output.space();
                     }
                 }
-                else if (output.pos() === 0 && c.type == "comment5" && output.option("shebang")) {
-                    output.print("#!" + c.value + "\n");
-                    output.indent();
-                }
             });
         }
     });
@@ -783,7 +777,7 @@ function OutputStream(options) {
     DEFPRINT(AST_Do, function(self, output){
         output.print("do");
         output.space();
-        self._do_print_body(output);
+        make_block(self.body, output);
         output.space();
         output.print("while");
         output.space();
@@ -910,10 +904,10 @@ function OutputStream(options) {
 
     /* -----[ if ]----- */
     function make_then(self, output) {
-        if (output.option("bracketize")) {
-            make_block(self.body, output);
-            return;
-        }
+        var b = self.body;
+        if (output.option("bracketize")
+            || !output.option("screw_ie8") && b instanceof AST_Do)
+            return make_block(b, output);
         // The squeezer replaces "block"-s that contain only a single
         // statement with the statement itself; technically, the AST
         // is correct, but this can create problems when we output an
@@ -921,18 +915,7 @@ function OutputStream(options) {
         // IF *without* an ELSE block (then the outer ELSE would refer
         // to the inner IF).  This function checks for this case and
         // adds the block brackets if needed.
-        if (!self.body)
-            return output.force_semicolon();
-        if (self.body instanceof AST_Do) {
-            // Unconditionally use the if/do-while workaround for all browsers.
-            // https://github.com/mishoo/UglifyJS/issues/#issue/57 IE
-            // croaks with "syntax error" on code like this: if (foo)
-            // do ... while(cond); else ...  we need block brackets
-            // around do/while
-            make_block(self.body, output);
-            return;
-        }
-        var b = self.body;
+        if (!b) return output.force_semicolon();
         while (true) {
             if (b instanceof AST_If) {
                 if (!b.alternative) {
@@ -1341,15 +1324,7 @@ function OutputStream(options) {
 
     function force_statement(stat, output) {
         if (output.option("bracketize")) {
-            if (!stat || stat instanceof AST_EmptyStatement)
-                output.print("{}");
-            else if (stat instanceof AST_BlockStatement)
-                stat.print(output);
-            else output.with_block(function(){
-                output.indent();
-                stat.print(output);
-                output.newline();
-            });
+            make_block(stat, output);
         } else {
             if (!stat || stat instanceof AST_EmptyStatement)
                 output.force_semicolon();
@@ -1398,11 +1373,11 @@ function OutputStream(options) {
     };
 
     function make_block(stmt, output) {
-        if (stmt instanceof AST_BlockStatement) {
+        if (!stmt || stmt instanceof AST_EmptyStatement)
+            output.print("{}");
+        else if (stmt instanceof AST_BlockStatement)
             stmt.print(output);
-            return;
-        }
-        output.with_block(function(){
+        else output.with_block(function(){
             output.indent();
             stmt.print(output);
             output.newline();
diff --git a/lib/parse.js b/lib/parse.js
index 9b198ccd..25fe9319 100644
--- a/lib/parse.js
+++ b/lib/parse.js
@@ -558,6 +558,11 @@ function tokenizer($TEXT, filename, html5_comments, shebang) {
     function next_token(force_regexp) {
         if (force_regexp != null)
             return read_regexp(force_regexp);
+        if (shebang && S.pos == 0 && looking_at("#!")) {
+            start_token();
+            forward(2);
+            skip_line_comment("comment5");
+        }
         for (;;) {
             skip_whitespace();
             start_token();
@@ -589,13 +594,6 @@ function tokenizer($TEXT, filename, html5_comments, shebang) {
             if (PUNC_CHARS(ch)) return token("punc", next());
             if (OPERATOR_CHARS(ch)) return read_operator();
             if (code == 92 || is_identifier_start(code)) return read_word();
-            if (shebang) {
-                if (S.pos == 0 && looking_at("#!")) {
-                    forward(2);
-                    skip_line_comment("comment5");
-                    continue;
-                }
-            }
             break;
         }
         parse_error("Unexpected character '" + ch + "'");
@@ -930,11 +928,9 @@ function parse($TEXT, options) {
                     expression : parenthesised(),
                     body       : statement()
                 });
-
-              default:
-                unexpected();
             }
         }
+        unexpected();
     });
 
     function labeled_statement() {
diff --git a/lib/scope.js b/lib/scope.js
index ae0c5777..483503ee 100644
--- a/lib/scope.js
+++ b/lib/scope.js
@@ -97,7 +97,7 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
     var labels = new Dictionary();
     var defun = null;
     var tw = new TreeWalker(function(node, descend){
-        if (options.screw_ie8 && node instanceof AST_Catch) {
+        if (node instanceof AST_Catch) {
             var save_scope = scope;
             scope = new AST_Scope(node);
             scope.init_scope_vars();
@@ -154,12 +154,10 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
         }
         else if (node instanceof AST_SymbolVar
                  || node instanceof AST_SymbolConst) {
-            var def = defun.def_variable(node);
-            def.init = tw.parent().value;
+            defun.def_variable(node);
         }
         else if (node instanceof AST_SymbolCatch) {
-            (options.screw_ie8 ? scope : defun)
-                .def_variable(node);
+            scope.def_variable(node);
         }
         else if (node instanceof AST_LabelRef) {
             var sym = labels.get(node.name);
@@ -209,6 +207,24 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
     });
     self.walk(tw);
 
+    // pass 3: fix up any scoping issue with IE8
+    if (!options.screw_ie8) {
+        self.walk(new TreeWalker(function(node, descend) {
+            if (node instanceof AST_SymbolCatch) {
+                var name = node.name;
+                var refs = node.thedef.references;
+                var scope = node.thedef.scope.parent_scope;
+                var def = scope.find_variable(name) || self.globals.get(name) || scope.def_variable(node);
+                refs.forEach(function(ref) {
+                    ref.thedef = def;
+                    ref.reference(options);
+                });
+                node.thedef = def;
+                return true;
+            }
+        }));
+    }
+
     if (options.cache) {
         this.cname = options.cache.cname;
     }
diff --git a/lib/utils.js b/lib/utils.js
index da663546..fdb20471 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -126,9 +126,11 @@ function merge(obj, ext) {
     return count;
 };
 
-function noop() {};
+function noop() {}
 function return_false() { return false; }
 function return_true() { return true; }
+function return_this() { return this; }
+function return_null() { return null; }
 
 var MAP = (function(){
     function MAP(a, f, backwards) {
diff --git a/package.json b/package.json
index 33bfc236..2ba24c7c 100644
--- a/package.json
+++ b/package.json
@@ -4,7 +4,7 @@
   "homepage": "http://lisperator.net/uglifyjs",
   "author": "Mihai Bazon <mihai.bazon@gmail.com> (http://lisperator.net/)",
   "license": "BSD-2-Clause",
-  "version": "2.8.4",
+  "version": "2.8.12",
   "engines": {
     "node": ">=0.8.0"
   },
@@ -29,7 +29,6 @@
     "LICENSE"
   ],
   "dependencies": {
-    "async": "~0.2.6",
     "source-map": "~0.5.1",
     "uglify-to-browserify": "~1.0.0",
     "yargs": "~3.10.0"
diff --git a/test/benchmark.js b/test/benchmark.js
index dc176a88..c150e5cf 100644
--- a/test/benchmark.js
+++ b/test/benchmark.js
@@ -24,26 +24,57 @@ var results = {};
 var remaining = 2 * urls.length;
 function done() {
     if (!--remaining) {
+        var failures = [];
         urls.forEach(function(url) {
+            var info = results[url];
             console.log();
             console.log(url);
-            console.log(results[url].time);
-            console.log("SHA1:", results[url].sha1);
+            console.log(info.log);
+            var elapsed = 0;
+            info.log.replace(/: ([0-9]+\.[0-9]{3})s/g, function(match, time) {
+                elapsed += parseFloat(time);
+            });
+            console.log("Run-time:", elapsed.toFixed(3), "s");
+            console.log("Original:", info.input, "bytes");
+            console.log("Uglified:", info.output, "bytes");
+            console.log("SHA1 sum:", info.sha1);
+            if (info.code) {
+                failures.push(url);
+            }
         });
+        if (failures.length) {
+            console.error("Benchmark failed:");
+            failures.forEach(function(url) {
+                console.error(url);
+            });
+            process.exit(1);
+        }
     }
 }
 urls.forEach(function(url) {
-    results[url] = { time: "" };
+    results[url] = {
+        input: 0,
+        output: 0,
+        log: ""
+    };
     require(url.slice(0, url.indexOf(":"))).get(url, function(res) {
         var uglifyjs = fork("bin/uglifyjs", args, { silent: true });
-        res.pipe(uglifyjs.stdin);
-        uglifyjs.stdout.pipe(createHash("sha1")).on("data", function(data) {
+        res.on("data", function(data) {
+            results[url].input += data.length;
+        }).pipe(uglifyjs.stdin);
+        uglifyjs.stdout.on("data", function(data) {
+            results[url].output += data.length;
+        }).pipe(createHash("sha1")).on("data", function(data) {
             results[url].sha1 = data.toString("hex");
             done();
         });
         uglifyjs.stderr.setEncoding("utf8");
         uglifyjs.stderr.on("data", function(data) {
-            results[url].time += data;
-        }).on("end", done)
+            results[url].log += data;
+        });
+        uglifyjs.on("exit", function(code) {
+            results[url].code = code;
+            done();
+        });
     });
 });
diff --git a/test/compress/collapse_vars.js b/test/compress/collapse_vars.js
index 5f63488f..558a9ee0 100644
--- a/test/compress/collapse_vars.js
+++ b/test/compress/collapse_vars.js
@@ -344,9 +344,9 @@ collapse_vars_do_while: {
     }
     input: {
         function f1(y) {
-            // The constant do-while condition `c` will be replaced.
+            // The constant do-while condition `c` will not be replaced.
             var c = 9;
-            do { } while (c === 77);
+            do {} while (c === 77);
         }
         function f2(y) {
             // The non-constant do-while condition `c` will not be replaced.
@@ -381,7 +381,8 @@ collapse_vars_do_while: {
     }
     expect: {
         function f1(y) {
-            do ; while (false);
+            var c = 9;
+            do ; while (77 === c);
         }
         function f2(y) {
             var c = 5 - y;
@@ -418,9 +419,9 @@ collapse_vars_do_while_drop_assign: {
     }
     input: {
         function f1(y) {
-            // The constant do-while condition `c` will be replaced.
+            // The constant do-while condition `c` will be not replaced.
             var c = 9;
-            do { } while (c === 77);
+            do {} while (c === 77);
         }
         function f2(y) {
             // The non-constant do-while condition `c` will not be replaced.
@@ -455,7 +456,8 @@ collapse_vars_do_while_drop_assign: {
     }
     expect: {
         function f1(y) {
-            do ; while (false);
+            var c = 9;
+            do ; while (77 === c);
         }
         function f2(y) {
             var c = 5 - y;
@@ -1150,7 +1152,8 @@ collapse_vars_arguments: {
     options = {
         collapse_vars:true, sequences:true, properties:true, dead_code:true, conditionals:true,
         comparisons:true, evaluate:true, booleans:true, loops:true, unused:true, hoist_funs:true,
-        keep_fargs:true, if_return:true, join_vars:true, cascade:true, side_effects:true
+        keep_fargs:true, if_return:true, join_vars:true, cascade:true, side_effects:true,
+        toplevel:true
     }
     input: {
         var outer = function() {
@@ -1309,9 +1312,99 @@ collapse_vars_regexp: {
             };
         }
         (function(){
-            var result, rx = /ab*/g;
-            while (result = rx.exec('acdabcdeabbb'))
+            var result, s = "acdabcdeabbb", rx = /ab*/g;
+            while (result = rx.exec(s))
                 console.log(result[0]);
         })();
     }
 }
+
+issue_1537: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var k = '';
+        for (k in {prop: 'val'}){}
+    }
+    expect: {
+        var k = '';
+        for (k in {prop: 'val'});
+    }
+}
+
+issue_1562: {
+    options = {
+        collapse_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var v = 1, B = 2;
+        for (v in objs) f(B);
+
+        var x = 3, C = 10;
+        while(x + 2) bar(C);
+
+        var y = 4, D = 20;
+        do bar(D); while(y + 2);
+
+        var z = 5, E = 30;
+        for (; f(z + 2) ;) bar(E);
+    }
+    expect: {
+        var v = 1;
+        for (v in objs) f(2);
+
+        var x = 3;
+        while(x + 2) bar(10);
+
+        var y = 4;
+        do bar(20); while(y + 2);
+
+        var z = 5;
+        for (; f(z + 2) ;) bar(30);
+    }
+}
+
+issue_1605_1: {
+    options = {
+        collapse_vars: true,
+        toplevel: false,
+    }
+    input: {
+        function foo(x) {
+            var y = x;
+            return y;
+        }
+        var o = new Object;
+        o.p = 1;
+    }
+    expect: {
+        function foo(x) {
+            return x;
+        }
+        var o = new Object;
+        o.p = 1;
+    }
+}
+
+issue_1605_2: {
+    options = {
+        collapse_vars: true,
+        toplevel: "vars",
+    }
+    input: {
+        function foo(x) {
+            var y = x;
+            return y;
+        }
+        var o = new Object;
+        o.p = 1;
+    }
+    expect: {
+        function foo(x) {
+            return x;
+        }
+        (new Object).p = 1;
+    }
+}
diff --git a/test/compress/dead-code.js b/test/compress/dead-code.js
index cd96d02d..45b7af6e 100644
--- a/test/compress/dead-code.js
+++ b/test/compress/dead-code.js
@@ -123,6 +123,7 @@ dead_code_const_annotation: {
         conditionals : true,
         evaluate     : true,
         reduce_vars  : true,
+        toplevel     : true,
     };
     input: {
         var unused;
@@ -172,6 +173,7 @@ dead_code_const_annotation_complex_scope: {
         conditionals : true,
         evaluate     : true,
         reduce_vars  : true,
+        toplevel     : true,
     };
     input: {
         var unused_var;
diff --git a/test/compress/drop-unused.js b/test/compress/drop-unused.js
index c1ca1b55..9f3bf77d 100644
--- a/test/compress/drop-unused.js
+++ b/test/compress/drop-unused.js
@@ -632,7 +632,7 @@ iife: {
     }
     expect: {
         function f() {
-            ~function() {}(b);
+            b;
         }
     }
 }
@@ -679,3 +679,115 @@ const_assign: {
         }
     }
 }
+
+issue_1539: {
+    options = {
+        cascade: true,
+        sequences: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            var a, b;
+            a = b = 42;
+            return a;
+        }
+    }
+    expect: {
+        function f() {
+            return 42;
+        }
+    }
+}
+
+vardef_value: {
+    options = {
+        keep_fnames: false,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            function g(){
+                return x();
+            }
+            var a = g();
+            return a(42);
+        }
+    }
+    expect: {
+        function f() {
+            var a = function(){
+                return x();
+            }();
+            return a(42);
+        }
+    }
+}
+
+assign_binding: {
+    options = {
+        cascade: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            var a;
+            a = f.g, a();
+        }
+    }
+    expect: {
+        function f() {
+            (0, f.g)();
+        }
+    }
+}
+
+assign_chain: {
+    options = {
+        unused: true,
+    }
+    input: {
+        function f() {
+            var a, b;
+            x = a = y = b = 42;
+        }
+    }
+    expect: {
+        function f() {
+            x = y = 42;
+        }
+    }
+}
+
+issue_1583: {
+    options = {
+        keep_fargs: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        function m(t) {
+            (function(e) {
+                t = e();
+            })(function() {
+                return (function(a) {
+                    return a;
+                })(function(a) {});
+            });
+        }
+    }
+    expect: {
+        function m(t) {
+            (function(e) {
+                t = (function() {
+                    return (function(a) {
+                        return a;
+                    })(function(a) {});
+                })();
+            })();
+        }
+    }
+}
diff --git a/test/compress/evaluate.js b/test/compress/evaluate.js
index 26b6e489..68739503 100644
--- a/test/compress/evaluate.js
+++ b/test/compress/evaluate.js
@@ -640,9 +640,7 @@ call_args: {
     expect: {
         const a = 1;
         console.log(1);
-        +function(a) {
-            return 1;
-        }(1);
+        +(1, 1);
     }
 }
 
@@ -663,9 +661,7 @@ call_args_drop_param: {
     expect: {
         const a = 1;
         console.log(1);
-        +function() {
-            return 1;
-        }(b);
+        +(b, 1);
     }
 }
 
diff --git a/test/compress/functions.js b/test/compress/functions.js
index d3d99b57..a1a515a1 100644
--- a/test/compress/functions.js
+++ b/test/compress/functions.js
@@ -35,9 +35,9 @@ iifes_returning_constants_keep_fargs_true: {
         console.log("okay");
         console.log(123);
         console.log(void 0);
-        console.log(function(x,y,z){return 2}(1,2,3));
-        console.log(function(x,y){return 6}(2,3));
-        console.log(function(x, y){return 6}(2,3,a(),b()));
+        console.log(2);
+        console.log(6);
+        console.log((a(), b(), 6));
     }
 }
 
@@ -71,6 +71,23 @@ iifes_returning_constants_keep_fargs_false: {
         console.log(void 0);
         console.log(2);
         console.log(6);
-        console.log(function(){return 6}(a(),b()));
+        console.log((a(), b(), 6));
+    }
+}
+
+issue_485_crashing_1530: {
+    options = {
+        conditionals: true,
+        dead_code: true,
+        evaluate: true,
+    }
+    input: {
+        (function(a) {
+            if (true) return;
+            var b = 42;
+        })(this);
+    }
+    expect: {
+        this, void 0;
     }
 }
diff --git a/test/compress/issue-1443.js b/test/compress/issue-1443.js
index a2565872..304a71ac 100644
--- a/test/compress/issue-1443.js
+++ b/test/compress/issue-1443.js
@@ -2,6 +2,7 @@
 
 unsafe_undefined: {
     options = {
+        conditionals: true,
         if_return: true,
         unsafe: true
     }
@@ -19,12 +20,7 @@ unsafe_undefined: {
     expect: {
         function f(n) {
             return function() {
-                if (a)
-                    return b;
-                if (c)
-                    return d;
-                else
-                    return n;
+                return a ? b : c ? d : n;
             };
         }
     }
@@ -32,6 +28,7 @@ unsafe_undefined: {
 
 keep_fnames: {
     options = {
+        conditionals: true,
         if_return: true,
         unsafe: true
     }
@@ -57,12 +54,7 @@ keep_fnames: {
                 function n(n) {
                     return n * n;
                 }
-                if (a)
-                    return b;
-                if (c)
-                    return d;
-                else
-                    return r;
+                return a ? b : c ? d : r;
             };
         }
     }
diff --git a/test/compress/issue-1569.js b/test/compress/issue-1569.js
new file mode 100644
index 00000000..5f0bca34
--- /dev/null
+++ b/test/compress/issue-1569.js
@@ -0,0 +1,19 @@
+inner_reference: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        !function f(a) {
+            return a && f(a - 1) + a;
+        }(42);
+        !function g(a) {
+            return a;
+        }(42);
+    }
+    expect: {
+        !function f(a) {
+            return a && f(a - 1) + a;
+        }(42);
+        !void 0;
+    }
+}
diff --git a/test/compress/issue-1588.js b/test/compress/issue-1588.js
new file mode 100644
index 00000000..ff25635c
--- /dev/null
+++ b/test/compress/issue-1588.js
@@ -0,0 +1,87 @@
+screw_ie8: {
+    options = {
+        screw_ie8: true,
+    }
+    mangle = {
+        screw_ie8: true,
+    }
+    input: {
+        try { throw "foo"; } catch (x) { console.log(x); }
+    }
+    expect_exact: 'try{throw"foo"}catch(o){console.log(o)}'
+    expect_stdout: [
+        "foo"
+    ]
+}
+
+support_ie8: {
+    options = {
+        screw_ie8: false,
+    }
+    mangle = {
+        screw_ie8: false,
+    }
+    input: {
+        try { throw "foo"; } catch (x) { console.log(x); }
+    }
+    expect_exact: 'try{throw"foo"}catch(x){console.log(x)}'
+    expect_stdout: "foo"
+}
+
+safe_undefined: {
+    options = {
+        conditionals: true,
+        if_return: true,
+        unsafe: false,
+    }
+    mangle = {}
+    input: {
+        var a, c;
+        console.log(function(undefined) {
+            return function() {
+                if (a)
+                    return b;
+                if (c)
+                    return d;
+            };
+        }(1)());
+    }
+    expect: {
+        var a, c;
+        console.log(function(n) {
+            return function() {
+                return a ? b : c ? d : void 0;
+            };
+        }(1)());
+    }
+    expect_stdout: true
+}
+
+unsafe_undefined: {
+    options = {
+        conditionals: true,
+        if_return: true,
+        unsafe: true,
+    }
+    mangle = {}
+    input: {
+        var a, c;
+        console.log(function(undefined) {
+            return function() {
+                if (a)
+                    return b;
+                if (c)
+                    return d;
+            };
+        }()());
+    }
+    expect: {
+        var a, c;
+        console.log(function(n) {
+            return function() {
+                return a ? b : c ? d : n;
+            };
+        }()());
+    }
+    expect_stdout: true
+}
diff --git a/test/compress/issue-1609.js b/test/compress/issue-1609.js
new file mode 100644
index 00000000..577a3ee1
--- /dev/null
+++ b/test/compress/issue-1609.js
@@ -0,0 +1,56 @@
+chained_evaluation_1: {
+    options = {
+        collapse_vars: true,
+        evaluate: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            var a = 1;
+            (function() {
+                var b = a, c;
+                c = f(b);
+                c.bar = b;
+            })();
+        })();
+    }
+    expect: {
+        (function() {
+            (function() {
+                var c;
+                c = f(1);
+                c.bar = 1;
+            })();
+        })();
+    }
+}
+
+chained_evaluation_2: {
+    options = {
+        collapse_vars: true,
+        evaluate: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            var a = "long piece of string";
+            (function() {
+                var b = a, c;
+                c = f(b);
+                c.bar = b;
+            })();
+        })();
+    }
+    expect: {
+        (function() {
+            var a = "long piece of string";
+            (function() {
+                var c;
+                c = f(a);
+                c.bar = a;
+            })();
+        })();
+    }
+}
diff --git a/test/compress/issue-368.js b/test/compress/issue-368.js
new file mode 100644
index 00000000..5960aa64
--- /dev/null
+++ b/test/compress/issue-368.js
@@ -0,0 +1,55 @@
+collapse: {
+    options = {
+        cascade: true,
+        sequences: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        function f1() {
+            var a;
+            a = typeof b === 'function' ? b() : b;
+            return a !== undefined && c();
+        }
+        function f2(b) {
+            var a;
+            b = c();
+            a = typeof b === 'function' ? b() : b;
+            return 'stirng' == typeof a && d();
+        }
+        function f3(c) {
+            var a;
+            a = b(a / 2);
+            if (a < 0) {
+                a++;
+                ++c;
+                return c / 2;
+            }
+        }
+        function f4(c) {
+            var a;
+            a = b(a / 2);
+            if (a < 0) {
+                a++;
+                c++;
+                return c / 2;
+            }
+        }
+    }
+    expect: {
+        function f1() {
+            return void 0 !== ('function' === typeof b ? b() : b) && c();
+        }
+        function f2(b) {
+            return b = c(), 'stirng' == typeof ('function' === typeof b ? b() : b) && d();
+        }
+        function f3(c) {
+            var a;
+            if ((a = b(a / 2)) < 0) return a++, ++c / 2;
+        }
+        function f4(c) {
+            var a;
+            if ((a = b(a / 2)) < 0) return a++, ++c / 2;
+        }
+    }
+}
diff --git a/test/compress/issue-640.js b/test/compress/issue-640.js
new file mode 100644
index 00000000..dd3f3f21
--- /dev/null
+++ b/test/compress/issue-640.js
@@ -0,0 +1,317 @@
+cond_5: {
+    options = {
+        conditionals: true,
+        expression: true,
+    }
+    input: {
+        if (some_condition()) {
+            if (some_other_condition()) {
+                do_something();
+            } else {
+                alternate();
+            }
+        } else {
+            alternate();
+        }
+
+        if (some_condition()) {
+            if (some_other_condition()) {
+                do_something();
+            }
+        }
+    }
+    expect: {
+        some_condition() && some_other_condition() ? do_something() : alternate();
+        if (some_condition() && some_other_condition()) do_something();
+    }
+}
+
+dead_code_const_annotation_regex: {
+    options = {
+        booleans     : true,
+        conditionals : true,
+        dead_code    : true,
+        evaluate     : true,
+        expression   : true,
+        loops        : true,
+    }
+    input: {
+        var unused;
+        // @constraint this shouldn't be a constant
+        var CONST_FOO_ANN = false;
+        if (CONST_FOO_ANN) {
+            console.log("reachable");
+        }
+    }
+    expect: {
+        var unused;
+        var CONST_FOO_ANN = !1;
+        if (CONST_FOO_ANN) console.log('reachable');
+    }
+}
+
+drop_console_2: {
+    options = {
+        drop_console: true,
+        expression: true,
+    }
+    input: {
+        console.log('foo');
+        console.log.apply(console, arguments);
+    }
+    expect: {
+        // with regular compression these will be stripped out as well
+        void 0;
+        void 0;
+    }
+}
+
+drop_value: {
+    options = {
+        expression: true,
+        side_effects: true,
+    }
+    input: {
+        (1, [2, foo()], 3, {a:1, b:bar()});
+    }
+    expect: {
+        foo(), {a:1, b:bar()};
+    }
+}
+
+wrongly_optimized: {
+    options = {
+        conditionals: true,
+        booleans: true,
+        evaluate: true,
+        expression: true,
+    }
+    input: {
+        function func() {
+            foo();
+        }
+        if (func() || true) {
+            bar();
+        }
+    }
+    expect: {
+        function func() {
+            foo();
+        }
+        // TODO: optimize to `func(), bar()`
+        if (func(), !0) bar();
+    }
+}
+
+negate_iife_1: {
+    options = {
+        expression: true,
+        negate_iife: true,
+    }
+    input: {
+        (function(){ stuff() })();
+    }
+    expect: {
+        (function(){ stuff() })();
+    }
+}
+
+negate_iife_3: {
+    options = {
+        conditionals: true,
+        expression: true,
+        negate_iife: true,
+    }
+    input: {
+        (function(){ return t })() ? console.log(true) : console.log(false);
+    }
+    expect: {
+        (function(){ return t })() ? console.log(true) : console.log(false);
+    }
+}
+
+negate_iife_3_off: {
+    options = {
+        conditionals: true,
+        expression: true,
+        negate_iife: false,
+    }
+    input: {
+        (function(){ return t })() ? console.log(true) : console.log(false);
+    }
+    expect: {
+        (function(){ return t })() ? console.log(true) : console.log(false);
+    }
+}
+
+negate_iife_4: {
+    options = {
+        conditionals: true,
+        expression: true,
+        negate_iife: true,
+        sequences: true,
+    }
+    input: {
+        (function(){ return t })() ? console.log(true) : console.log(false);
+        (function(){
+            console.log("something");
+        })();
+    }
+    expect: {
+        (function(){ return t })() ? console.log(true) : console.log(false), function(){
+            console.log("something");
+        }();
+    }
+}
+
+negate_iife_5: {
+    options = {
+        conditionals: true,
+        expression: true,
+        negate_iife: true,
+        sequences: true,
+    }
+    input: {
+        if ((function(){ return t })()) {
+            foo(true);
+        } else {
+            bar(false);
+        }
+        (function(){
+            console.log("something");
+        })();
+    }
+    expect: {
+        (function(){ return t })() ? foo(true) : bar(false), function(){
+            console.log("something");
+        }();
+    }
+}
+
+negate_iife_5_off: {
+    options = {
+        conditionals: true,
+        expression: true,
+        negate_iife: false,
+        sequences: true,
+    };
+    input: {
+        if ((function(){ return t })()) {
+            foo(true);
+        } else {
+            bar(false);
+        }
+        (function(){
+            console.log("something");
+        })();
+    }
+    expect: {
+        (function(){ return t })() ? foo(true) : bar(false), function(){
+            console.log("something");
+        }();
+    }
+}
+
+issue_1254_negate_iife_true: {
+    options = {
+        expression: true,
+        negate_iife: true,
+    }
+    input: {
+        (function() {
+            return function() {
+                console.log('test')
+            };
+        })()();
+    }
+    expect_exact: '(function(){return function(){console.log("test")}})()();'
+}
+
+issue_1254_negate_iife_nested: {
+    options = {
+        expression: true,
+        negate_iife: true,
+    }
+    input: {
+        (function() {
+            return function() {
+                console.log('test')
+            };
+        })()()()()();
+    }
+    expect_exact: '(function(){return function(){console.log("test")}})()()()()();'
+}
+
+conditional: {
+    options = {
+        expression: true,
+        pure_funcs: [ "pure" ],
+        side_effects: true,
+    }
+    input: {
+        pure(1 | a() ? 2 & b() : 7 ^ c());
+        pure(1 | a() ? 2 & b() : 5);
+        pure(1 | a() ? 4 : 7 ^ c());
+        pure(1 | a() ? 4 : 5);
+        pure(3 ? 2 & b() : 7 ^ c());
+        pure(3 ? 2 & b() : 5);
+        pure(3 ? 4 : 7 ^ c());
+        pure(3 ? 4 : 5);
+    }
+    expect: {
+        1 | a() ? b() : c();
+        1 | a() && b();
+        1 | a() || c();
+        a();
+        3 ? b() : c();
+        3 && b();
+        3 || c();
+        pure(3 ? 4 : 5);
+    }
+}
+
+limit_1: {
+    options = {
+        expression: true,
+        sequences: 3,
+    }
+    input: {
+        a;
+        b;
+        c;
+        d;
+        e;
+        f;
+        g;
+        h;
+        i;
+        j;
+        k;
+    }
+    expect: {
+        // Turned into a single return statement
+        // so it can no longer be split into lines
+        a,b,c,d,e,f,g,h,i,j,k;
+    }
+}
+
+iife: {
+    options = {
+        expression: true,
+        sequences: true,
+    }
+    input: {
+        x = 42;
+        (function a() {})();
+        !function b() {}();
+        ~function c() {}();
+        +function d() {}();
+        -function e() {}();
+        void function f() {}();
+        typeof function g() {}();
+    }
+    expect: {
+        x = 42, function a() {}(), function b() {}(), function c() {}(),
+        function d() {}(), function e() {}(), function f() {}(), typeof function g() {}();
+    }
+}
diff --git a/test/compress/issue-973.js b/test/compress/issue-973.js
index 0e040922..30f886a8 100644
--- a/test/compress/issue-973.js
+++ b/test/compress/issue-973.js
@@ -50,6 +50,7 @@ this_binding_conditionals: {
 this_binding_collapse_vars: {
     options = {
         collapse_vars: true,
+        toplevel: true,
     };
     input: {
         var c = a; c();
diff --git a/test/compress/loops.js b/test/compress/loops.js
index ca05461c..7581e758 100644
--- a/test/compress/loops.js
+++ b/test/compress/loops.js
@@ -213,6 +213,228 @@ evaluate: {
             a();
         for(;;)
             c();
-        d();
+        // rule disabled due to issue_1532
+        do d(); while (false);
     }
 }
+
+issue_1532: {
+    options = {
+        evaluate: true,
+        loops: true,
+    }
+    input: {
+        function f(x, y) {
+            do {
+                if (x) break;
+                foo();
+            } while (false);
+        }
+    }
+    expect: {
+        function f(x, y) {
+            do {
+                if (x) break;
+                foo();
+            } while (false);
+        }
+    }
+}
+
+issue_186: {
+    beautify = {
+        beautify: false,
+        screw_ie8: true,
+    }
+    input: {
+        var x = 3;
+        if (foo())
+            do
+                do
+                    alert(x);
+                while (--x);
+            while (x);
+        else
+            bar();
+    }
+    expect_exact: 'var x=3;if(foo())do{do{alert(x)}while(--x)}while(x);else bar();'
+}
+
+issue_186_ie8: {
+    beautify = {
+        beautify: false,
+        screw_ie8: false,
+    }
+    input: {
+        var x = 3;
+        if (foo())
+            do
+                do
+                    alert(x);
+                while (--x);
+            while (x);
+        else
+            bar();
+    }
+    expect_exact: 'var x=3;if(foo()){do{do{alert(x)}while(--x)}while(x)}else bar();'
+}
+
+issue_186_beautify: {
+    beautify = {
+        beautify: true,
+        screw_ie8: true,
+    }
+    input: {
+        var x = 3;
+        if (foo())
+            do
+                do
+                    alert(x);
+                while (--x);
+            while (x);
+        else
+            bar();
+    }
+    expect_exact: [
+        'var x = 3;',
+        '',
+        'if (foo()) do {',
+        '    do {',
+        '        alert(x);',
+        '    } while (--x);',
+        '} while (x); else bar();',
+    ]
+}
+
+issue_186_beautify_ie8: {
+    beautify = {
+        beautify: true,
+        screw_ie8: false,
+    }
+    input: {
+        var x = 3;
+        if (foo())
+            do
+                do
+                    alert(x);
+                while (--x);
+            while (x);
+        else
+            bar();
+    }
+    expect_exact: [
+        'var x = 3;',
+        '',
+        'if (foo()) {',
+        '    do {',
+        '        do {',
+        '            alert(x);',
+        '        } while (--x);',
+        '    } while (x);',
+        '} else bar();',
+    ]
+}
+
+issue_186_bracketize: {
+    beautify = {
+        beautify: false,
+        bracketize: true,
+        screw_ie8: true,
+    }
+    input: {
+        var x = 3;
+        if (foo())
+            do
+                do
+                    alert(x);
+                while (--x);
+            while (x);
+        else
+            bar();
+    }
+    expect_exact: 'var x=3;if(foo()){do{do{alert(x)}while(--x)}while(x)}else{bar()}'
+}
+
+issue_186_bracketize_ie8: {
+    beautify = {
+        beautify: false,
+        bracketize: true,
+        screw_ie8: false,
+    }
+    input: {
+        var x = 3;
+        if (foo())
+            do
+                do
+                    alert(x);
+                while (--x);
+            while (x);
+        else
+            bar();
+    }
+    expect_exact: 'var x=3;if(foo()){do{do{alert(x)}while(--x)}while(x)}else{bar()}'
+}
+
+issue_186_beautify_bracketize: {
+    beautify = {
+        beautify: true,
+        bracketize: true,
+        screw_ie8: true,
+    }
+    input: {
+        var x = 3;
+        if (foo())
+            do
+                do
+                    alert(x);
+                while (--x);
+            while (x);
+        else
+            bar();
+    }
+    expect_exact: [
+        'var x = 3;',
+        '',
+        'if (foo()) {',
+        '    do {',
+        '        do {',
+        '            alert(x);',
+        '        } while (--x);',
+        '    } while (x);',
+        '} else {',
+        '    bar();',
+        '}',
+    ]
+}
+
+issue_186_beautify_bracketize_ie8: {
+    beautify = {
+        beautify: true,
+        bracketize: true,
+        screw_ie8: false,
+    }
+    input: {
+        var x = 3;
+        if (foo())
+            do
+                do
+                    alert(x);
+                while (--x);
+            while (x);
+        else
+            bar();
+    }
+    expect_exact: [
+        'var x = 3;',
+        '',
+        'if (foo()) {',
+        '    do {',
+        '        do {',
+        '            alert(x);',
+        '        } while (--x);',
+        '    } while (x);',
+        '} else {',
+        '    bar();',
+        '}',
+    ]
+}
diff --git a/test/compress/max_line_len.js b/test/compress/max_line_len.js
index b9e09178..7ad9ee0e 100644
--- a/test/compress/max_line_len.js
+++ b/test/compress/max_line_len.js
@@ -7,7 +7,13 @@ too_short: {
             return { c: 42, d: a(), e: "foo"};
         }
     }
-    expect_exact: 'function f(a){\nreturn{\nc:42,\nd:a(),\ne:"foo"}}'
+    expect_exact: [
+        'function f(a){',
+        'return{',
+        'c:42,',
+        'd:a(),',
+        'e:"foo"}}',
+    ]
     expect_warnings: [
         "WARN: Output exceeds 10 characters"
     ]
@@ -22,7 +28,12 @@ just_enough: {
             return { c: 42, d: a(), e: "foo"};
         }
     }
-    expect_exact: 'function f(a){\nreturn{c:42,\nd:a(),e:"foo"}\n}'
+    expect_exact: [
+        'function f(a){',
+        'return{c:42,',
+        'd:a(),e:"foo"}',
+        '}',
+    ]
     expect_warnings: [
     ]
 }
diff --git a/test/compress/negate-iife.js b/test/compress/negate-iife.js
index f17ae206..9a0b5a46 100644
--- a/test/compress/negate-iife.js
+++ b/test/compress/negate-iife.js
@@ -32,6 +32,19 @@ negate_iife_2: {
     }
 }
 
+negate_iife_2_side_effects: {
+    options = {
+        negate_iife: true,
+        side_effects: true,
+    }
+    input: {
+        (function(){ return {} })().x = 10; // should not transform this one
+    }
+    expect: {
+        (function(){ return {} })().x = 10;
+    }
+}
+
 negate_iife_3: {
     options = {
         negate_iife: true,
@@ -45,6 +58,34 @@ negate_iife_3: {
     }
 }
 
+negate_iife_3_evaluate: {
+    options = {
+        conditionals: true,
+        evaluate: true,
+        negate_iife: true,
+    }
+    input: {
+        (function(){ return true })() ? console.log(true) : console.log(false);
+    }
+    expect: {
+        console.log(true);
+    }
+}
+
+negate_iife_3_side_effects: {
+    options = {
+        conditionals: true,
+        negate_iife: true,
+        side_effects: true,
+    }
+    input: {
+        (function(){ return t })() ? console.log(true) : console.log(false);
+    }
+    expect: {
+        !function(){ return t }() ? console.log(false) : console.log(true);
+    }
+}
+
 negate_iife_3_off: {
     options = {
         negate_iife: false,
@@ -58,6 +99,20 @@ negate_iife_3_off: {
     }
 }
 
+negate_iife_3_off_evaluate: {
+    options = {
+        conditionals: true,
+        evaluate: true,
+        negate_iife: false,
+    }
+    input: {
+        (function(){ return true })() ? console.log(true) : console.log(false);
+    }
+    expect: {
+        console.log(true);
+    }
+}
+
 negate_iife_4: {
     options = {
         negate_iife: true,
@@ -320,3 +375,35 @@ issue_1288: {
         }(0);
     }
 }
+
+issue_1288_side_effects: {
+    options = {
+        conditionals: true,
+        negate_iife: true,
+        side_effects: true,
+    }
+    input: {
+        if (w) ;
+        else {
+            (function f() {})();
+        }
+        if (!x) {
+            (function() {
+                x = {};
+            })();
+        }
+        if (y)
+            (function() {})();
+        else
+            (function(z) {
+                return z;
+            })(0);
+    }
+    expect: {
+        w;
+        x || function() {
+            x = {};
+        }();
+        y;
+    }
+}
diff --git a/test/compress/numbers.js b/test/compress/numbers.js
index 8e32ad02..0b40bb9c 100644
--- a/test/compress/numbers.js
+++ b/test/compress/numbers.js
@@ -17,3 +17,139 @@ hex_numbers_in_parentheses_for_prototype_functions: {
     }
     expect_exact: "-2;(-2).toFixed(0);2;2..toFixed(0);.2;.2.toFixed(0);2e-8;2e-8.toFixed(0);0xde0b6b3a7640080;(0xde0b6b3a7640080).toFixed(0);"
 }
+
+comparisons: {
+    options = {
+        comparisons: true,
+    }
+    input: {
+        console.log(
+            ~x === 42,
+            x % n === 42
+        );
+    }
+    expect: {
+        console.log(
+            42 == ~x,
+            x % n == 42
+        );
+    }
+}
+
+evaluate_1: {
+    options = {
+        evaluate: true,
+        unsafe_math: false,
+    }
+    input: {
+        console.log(
+            x + 1 + 2,
+            x * 1 * 2,
+            +x + 1 + 2,
+            1 + x + 2 + 3,
+            1 | x | 2 | 3,
+            1 + x-- + 2 + 3,
+            1 + (x*y + 2) + 3,
+            1 + (2 + x + 3),
+            1 + (2 + ~x + 3),
+            -y + (2 + ~x + 3),
+            1 & (2 & x & 3),
+            1 + (2 + (x |= 0) + 3)
+        );
+    }
+    expect: {
+        console.log(
+            x + 1 + 2,
+            1 * x * 2,
+            +x + 1 + 2,
+            1 + x + 2 + 3,
+            3 | x,
+            1 + x-- + 2 + 3,
+            x*y + 2 + 1 + 3,
+            1 + (2 + x + 3),
+            2 + ~x + 3 + 1,
+            -y + (2 + ~x + 3),
+            0 & x,
+            2 + (x |= 0) + 3 + 1
+        );
+    }
+}
+
+evaluate_2: {
+    options = {
+        evaluate: true,
+        unsafe_math: true,
+    }
+    input: {
+        console.log(
+            x + 1 + 2,
+            x * 1 * 2,
+            +x + 1 + 2,
+            1 + x + 2 + 3,
+            1 | x | 2 | 3,
+            1 + x-- + 2 + 3,
+            1 + (x*y + 2) + 3,
+            1 + (2 + x + 3),
+            1 & (2 & x & 3),
+            1 + (2 + (x |= 0) + 3)
+        );
+    }
+    expect: {
+        console.log(
+            x + 1 + 2,
+            2 * x,
+            3 + +x,
+            1 + x + 2 + 3,
+            3 | x,
+            6 + x--,
+            6 + x*y,
+            1 + (2 + x + 3),
+            0 & x,
+            6 + (x |= 0)
+        );
+    }
+}
+
+evaluate_3: {
+    options = {
+        evaluate: true,
+        unsafe: true,
+        unsafe_math: true,
+    }
+    input: {
+        console.log(1 + Number(x) + 2);
+    }
+    expect: {
+        console.log(3 + +x);
+    }
+}
+
+evaluate_4: {
+    options = {
+        evaluate: true,
+    }
+    input: {
+        console.log(
+            1+ +a,
+            +a+1,
+            1+-a,
+            -a+1,
+            +a+ +b,
+            +a+-b,
+            -a+ +b,
+            -a+-b
+        );
+    }
+    expect: {
+        console.log(
+            +a+1,
+            +a+1,
+            1-a,
+            1-a,
+            +a+ +b,
+            +a-b,
+            -a+ +b,
+            -a-b
+        );
+    }
+}
diff --git a/test/compress/reduce_vars.js b/test/compress/reduce_vars.js
index e38c317b..bc6c72d4 100644
--- a/test/compress/reduce_vars.js
+++ b/test/compress/reduce_vars.js
@@ -6,6 +6,7 @@ reduce_vars: {
             C : 0
         },
         reduce_vars   : true,
+        toplevel      : true,
         unused        : true
     }
     input: {
@@ -452,22 +453,26 @@ multi_def_2: {
         reduce_vars: true,
     }
     input: {
-        if (code == 16)
-            var bitsLength = 2, bitsOffset = 3, what = len;
-        else if (code == 17)
-            var bitsLength = 3, bitsOffset = 3, what = (len = 0);
-        else if (code == 18)
-            var bitsLength = 7, bitsOffset = 11, what = (len = 0);
-        var repeatLength = this.getBits(bitsLength) + bitsOffset;
+        function f(){
+            if (code == 16)
+                var bitsLength = 2, bitsOffset = 3, what = len;
+            else if (code == 17)
+                var bitsLength = 3, bitsOffset = 3, what = (len = 0);
+            else if (code == 18)
+                var bitsLength = 7, bitsOffset = 11, what = (len = 0);
+            var repeatLength = this.getBits(bitsLength) + bitsOffset;
+        }
     }
     expect: {
-        if (16 == code)
-            var bitsLength = 2, bitsOffset = 3, what = len;
-        else if (17 == code)
-            var bitsLength = 3, bitsOffset = 3, what = (len = 0);
-        else if (18 == code)
-            var bitsLength = 7, bitsOffset = 11, what = (len = 0);
-        var repeatLength = this.getBits(bitsLength) + bitsOffset;
+        function f(){
+            if (16 == code)
+                var bitsLength = 2, bitsOffset = 3, what = len;
+            else if (17 == code)
+                var bitsLength = 3, bitsOffset = 3, what = (len = 0);
+            else if (18 == code)
+                var bitsLength = 7, bitsOffset = 11, what = (len = 0);
+            var repeatLength = this.getBits(bitsLength) + bitsOffset;
+        }
     }
 }
 
@@ -477,12 +482,16 @@ use_before_var: {
         reduce_vars: true,
     }
     input: {
-        console.log(t);
-        var t = 1;
+        function f(){
+            console.log(t);
+            var t = 1;
+        }
     }
     expect: {
-        console.log(t);
-        var t = 1;
+        function f(){
+            console.log(t);
+            var t = 1;
+        }
     }
 }
 
@@ -492,22 +501,20 @@ inner_var_if: {
         reduce_vars: true,
     }
     input: {
-        function f(){
-            return 0;
+        function f(a){
+            if (a)
+                var t = 1;
+            if (!t)
+                console.log(t);
         }
-        if (f())
-            var t = 1;
-        if (!t)
-            console.log(t);
     }
     expect: {
-        function f(){
-            return 0;
+        function f(a){
+            if (a)
+                var t = 1;
+            if (!t)
+                console.log(t);
         }
-        if (f())
-            var t = 1;
-        if (!t)
-            console.log(t);
     }
 }
 
@@ -517,24 +524,22 @@ inner_var_label: {
         reduce_vars: true,
     }
     input: {
-        function f(){
-            return 1;
+        function f(a){
+            l: {
+                if (a) break l;
+                var t = 1;
+            }
+            console.log(t);
         }
-        l: {
-            if (f()) break l;
-            var t = 1;
-        }
-        console.log(t);
     }
     expect: {
-        function f(){
-            return 1;
+        function f(a){
+            l: {
+                if (a) break l;
+                var t = 1;
+            }
+            console.log(t);
         }
-        l: {
-            if (f()) break l;
-            var t = 1;
-        }
-        console.log(t);
     }
 }
 
@@ -544,48 +549,805 @@ inner_var_for: {
         reduce_vars: true,
     }
     input: {
-        var a = 1;
-        x(a, b, d);
-        for (var b = 2, c = 3; x(a, b, c, d); x(a, b, c, d)) {
-            var d = 4, e = 5;
+        function f() {
+            var a = 1;
+            x(a, b, d);
+            for (var b = 2, c = 3; x(a, b, c, d); x(a, b, c, d)) {
+                var d = 4, e = 5;
+                x(a, b, c, d, e);
+            }
             x(a, b, c, d, e);
         }
-        x(a, b, c, d, e)
     }
     expect: {
-        var a = 1;
-        x(1, b, d);
-        for (var b = 2, c = 3; x(1, b, 3, d); x(1, b, 3, d)) {
-            var d = 4, e = 5;
+        function f() {
+            var a = 1;
+            x(1, b, d);
+            for (var b = 2, c = 3; x(1, b, 3, d); x(1, b, 3, d)) {
+                var d = 4, e = 5;
+                x(1, b, 3, d, e);
+            }
             x(1, b, 3, d, e);
         }
-        x(1, b, 3, d, e);
     }
 }
 
-inner_var_for_in: {
+inner_var_for_in_1: {
     options = {
         evaluate: true,
         reduce_vars: true,
     }
     input: {
-        var a = 1, b = 2;
-        for (b in (function() {
-            return x(a, b, c);
-        })()) {
-            var c = 3, d = 4;
+        function f() {
+            var a = 1, b = 2;
+            for (b in (function() {
+                return x(a, b, c);
+            })()) {
+                var c = 3, d = 4;
+                x(a, b, c, d);
+            }
             x(a, b, c, d);
         }
-        x(a, b, c, d);
     }
     expect: {
-        var a = 1, b = 2;
-        for (b in (function() {
-            return x(1, b, c);
-        })()) {
-            var c = 3, d = 4;
+        function f() {
+            var a = 1, b = 2;
+            for (b in (function() {
+                return x(1, b, c);
+            })()) {
+                var c = 3, d = 4;
+                x(1, b, c, d);
+            }
             x(1, b, c, d);
         }
-        x(1, b, c, d);
+    }
+}
+
+inner_var_for_in_2: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+    }
+    input: {
+        function f() {
+            for (var long_name in {})
+                console.log(long_name);
+        }
+    }
+    expect: {
+        function f() {
+            for (var long_name in {})
+                console.log(long_name);
+        }
+    }
+}
+
+inner_var_catch: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+    }
+    input: {
+        function f() {
+            try {
+                a();
+            } catch (e) {
+                var b = 1;
+            }
+            console.log(b);
+        }
+    }
+    expect: {
+        function f() {
+            try {
+                a();
+            } catch (e) {
+                var b = 1;
+            }
+            console.log(b);
+        }
+    }
+}
+
+issue_1533_1: {
+    options = {
+        collapse_vars: true,
+        reduce_vars: true,
+    }
+    input: {
+        function f() {
+            var id = "";
+            for (id in {break: "me"})
+                console.log(id);
+        }
+    }
+    expect: {
+        function f() {
+            var id = "";
+            for (id in {break: "me"})
+                console.log(id);
+        }
+    }
+}
+
+issue_1533_2: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+    }
+    input: {
+        function f() {
+            var id = "";
+            for (var id in {break: "me"})
+                console.log(id);
+            console.log(id);
+        }
+    }
+    expect: {
+        function f() {
+            var id = "";
+            for (var id in {break: "me"})
+                console.log(id);
+            console.log(id);
+        }
+    }
+}
+
+toplevel_on: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel:true,
+        unused: true,
+    }
+    input: {
+        var x = 3;
+        console.log(x);
+    }
+    expect: {
+        console.log(3);
+    }
+}
+
+toplevel_off: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel:false,
+        unused: true,
+    }
+    input: {
+        var x = 3;
+        console.log(x);
+    }
+    expect: {
+        var x = 3;
+        console.log(x);
+    }
+}
+
+toplevel_on_loops_1: {
+    options = {
+        evaluate: true,
+        loops: true,
+        reduce_vars: true,
+        toplevel:true,
+        unused: true,
+    }
+    input: {
+        function bar() {
+            console.log("bar:", --x);
+        }
+        var x = 3;
+        do
+            bar();
+        while (x);
+    }
+    expect: {
+        var x = 3;
+        do
+            (function() {
+                console.log("bar:", --x);
+            })();
+        while (x);
+    }
+}
+
+toplevel_off_loops_1: {
+    options = {
+        evaluate: true,
+        loops: true,
+        reduce_vars: true,
+        toplevel:false,
+        unused: true,
+    }
+    input: {
+        function bar() {
+            console.log("bar:", --x);
+        }
+        var x = 3;
+        do
+            bar();
+        while (x);
+    }
+    expect: {
+        function bar() {
+            console.log("bar:", --x);
+        }
+        var x = 3;
+        do
+            bar();
+        while (x);
+    }
+}
+
+toplevel_on_loops_2: {
+    options = {
+        evaluate: true,
+        loops: true,
+        reduce_vars: true,
+        toplevel:true,
+        unused: true,
+    }
+    input: {
+        function bar() {
+            console.log("bar:");
+        }
+        var x = 3;
+        do
+            bar();
+        while (x);
+    }
+    expect: {
+        for (;;) (function() {
+            console.log("bar:");
+        })();
+    }
+}
+
+toplevel_off_loops_2: {
+    options = {
+        evaluate: true,
+        loops: true,
+        reduce_vars: true,
+        toplevel:false,
+        unused: true,
+    }
+    input: {
+        function bar() {
+            console.log("bar:");
+        }
+        var x = 3;
+        do
+            bar();
+        while (x);
+    }
+    expect: {
+        function bar() {
+            console.log("bar:");
+        }
+        var x = 3;
+        do
+            bar();
+        while (x);
+    }
+}
+
+toplevel_on_loops_3: {
+    options = {
+        evaluate: true,
+        loops: true,
+        reduce_vars: true,
+        toplevel:true,
+        unused: true,
+    }
+    input: {
+        var x = 3;
+        while (x) bar();
+    }
+    expect: {
+        for (;;) bar();
+    }
+}
+
+toplevel_off_loops_3: {
+    options = {
+        evaluate: true,
+        loops: true,
+        reduce_vars: true,
+        toplevel:false,
+        unused: true,
+    }
+    input: {
+        var x = 3;
+        while (x) bar();
+    }
+    expect: {
+        var x = 3;
+        for (;x;) bar();
+    }
+}
+
+defun_reference: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+    }
+    input: {
+        function f() {
+            function g() {
+                x();
+                return a;
+            }
+            var a = h();
+            var b = 2;
+            return a + b;
+            function h() {
+                y();
+                return b;
+            }
+        }
+    }
+    expect: {
+        function f() {
+            function g() {
+                x();
+                return a;
+            }
+            var a = h();
+            var b = 2;
+            return a + b;
+            function h() {
+                y();
+                return b;
+            }
+        }
+    }
+}
+
+defun_inline_1: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            return g(2) + h();
+            function g(b) {
+                return b;
+            }
+            function h() {
+                return h();
+            }
+        }
+    }
+    expect: {
+        function f() {
+            return function(b) {
+                return b;
+            }(2) + h();
+            function h() {
+                return h();
+            }
+        }
+    }
+}
+
+defun_inline_2: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            function g(b) {
+                return b;
+            }
+            function h() {
+                return h();
+            }
+            return g(2) + h();
+        }
+    }
+    expect: {
+        function f() {
+            function h() {
+                return h();
+            }
+            return function(b) {
+                return b;
+            }(2) + h();
+        }
+    }
+}
+
+defun_inline_3: {
+    options = {
+        evaluate: true,
+        passes: 2,
+        reduce_vars: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            return g(2);
+            function g(b) {
+                return b;
+            }
+        }
+    }
+    expect: {
+        function f() {
+            return 2;
+        }
+    }
+}
+
+defun_call: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            return g() + h(1) - h(g(), 2, 3);
+            function g() {
+                return 4;
+            }
+            function h(a) {
+                return a;
+            }
+        }
+    }
+    expect: {
+        function f() {
+            return 4 + h(1) - h(4);
+            function h(a) {
+                return a;
+            }
+        }
+    }
+}
+
+defun_redefine: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            function g() {
+                return 1;
+            }
+            function h() {
+                return 2;
+            }
+            g = function() {
+                return 3;
+            };
+            return g() + h();
+        }
+    }
+    expect:  {
+        function f() {
+            function g() {
+                return 1;
+            }
+            g = function() {
+                return 3;
+            };
+            return g() + 2;
+        }
+    }
+}
+
+func_inline: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            var g = function() {
+                return 1;
+            };
+            console.log(g() + h());
+            var h = function() {
+                return 2;
+            };
+        }
+    }
+    expect: {
+        function f() {
+            console.log(1 + h());
+            var h = function() {
+                return 2;
+            };
+        }
+    }
+}
+
+func_modified: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        function f(a) {
+            function a() { return 1; }
+            function b() { return 2; }
+            function c() { return 3; }
+            b.inject = [];
+            c = function() { return 4; };
+            return a() + b() + c();
+        }
+    }
+    expect: {
+        function f(a) {
+            function b() { return 2; }
+            function c() { return 3; }
+            b.inject = [];
+            c = function() { return 4; };
+            return 1 + 2 + c();
+        }
+    }
+}
+
+defun_label: {
+    options = {
+        passes: 2,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        !function() {
+            function f(a) {
+                L: {
+                    if (a) break L;
+                    return 1;
+                }
+            }
+            console.log(f(2));
+        }();
+    }
+    expect: {
+        !function() {
+            console.log(function(a) {
+                L: {
+                    if (a) break L;
+                    return 1;
+                }
+            }(2));
+        }();
+    }
+}
+
+double_reference: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            var g = function g() {
+                g();
+            };
+            g();
+        }
+    }
+    expect: {
+        function f() {
+            (function g() {
+                g();
+            })();
+        }
+    }
+}
+
+iife_arguments_1: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function(x) {
+            console.log(x() === arguments[0]);
+        })(function f() {
+            return f;
+        });
+    }
+    expect: {
+        (function(x) {
+            console.log(x() === arguments[0]);
+        })(function f() {
+            return f;
+        });
+    }
+}
+
+iife_arguments_2: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            var x = function f() {
+                return f;
+            };
+            console.log(x() === arguments[0]);
+        })();
+    }
+    expect: {
+        (function() {
+            console.log(function f() {
+                return f;
+            }() === arguments[0]);
+        })();
+    }
+}
+
+iife_eval_1: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function(x) {
+            console.log(x() === eval("x"));
+        })(function f() {
+            return f;
+        });
+    }
+    expect: {
+        (function(x) {
+            console.log(x() === eval("x"));
+        })(function f() {
+            return f;
+        });
+    }
+}
+
+iife_eval_2: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            var x = function f() {
+                return f;
+            };
+            console.log(x() === eval("x"));
+        })();
+    }
+    expect: {
+        (function() {
+            var x = function f() {
+                return f;
+            };
+            console.log(x() === eval("x"));
+        })();
+    }
+}
+
+iife_func_side_effects: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function(a, b, c) {
+            return b();
+        })(x(), function() {
+            return y();
+        }, z());
+    }
+    expect: {
+        (function(a, b, c) {
+            return function() {
+                return y();
+            }();
+        })(x(), 0, z());
+    }
+}
+
+issue_1595_1: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function f(a) {
+            return f(a + 1);
+        })(2);
+    }
+    expect: {
+        (function f(a) {
+            return f(a + 1);
+        })(2);
+    }
+}
+
+issue_1595_2: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function f(a) {
+            return g(a + 1);
+        })(2);
+    }
+    expect: {
+        (function(a) {
+            return g(a + 1);
+        })(2);
+    }
+}
+
+issue_1595_3: {
+    options = {
+        evaluate: true,
+        passes: 2,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function f(a) {
+            return g(a + 1);
+        })(2);
+    }
+    expect: {
+        (function(a) {
+            return g(3);
+        })();
+    }
+}
+
+issue_1595_4: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function iife(a, b, c) {
+            console.log(a, b, c);
+            if (a) iife(a - 1, b, c);
+        })(3, 4, 5);
+    }
+    expect: {
+        (function iife(a, b, c) {
+            console.log(a, b, c);
+            if (a) iife(a - 1, b, c);
+        })(3, 4, 5);
+    }
+}
+
+issue_1606: {
+    options = {
+        evaluate: true,
+        hoist_vars: true,
+        reduce_vars: true,
+    }
+    input: {
+        function f() {
+            var a;
+            function g(){};
+            var b = 2;
+            x(b);
+        }
+    }
+    expect: {
+        function f() {
+            var a, b;
+            function g(){};
+            b = 2;
+            x(b);
+        }
     }
 }
diff --git a/test/compress/screw-ie8.js b/test/compress/screw-ie8.js
index 31c448fd..4fbb95c8 100644
--- a/test/compress/screw-ie8.js
+++ b/test/compress/screw-ie8.js
@@ -17,6 +17,26 @@ dont_screw: {
     expect_exact: 'f("\\x0B");';
 }
 
+do_screw_constants: {
+    options = {
+        screw_ie8: true,
+    }
+    input: {
+        f(undefined, Infinity);
+    }
+    expect_exact: "f(void 0,1/0);"
+}
+
+dont_screw_constants: {
+    options = {
+        screw_ie8: false,
+    }
+    input: {
+        f(undefined, Infinity);
+    }
+    expect_exact: "f(undefined,Infinity);"
+}
+
 do_screw_try_catch: {
     options = { screw_ie8: true };
     mangle = { screw_ie8: true };
@@ -46,8 +66,6 @@ do_screw_try_catch: {
 }
 
 dont_screw_try_catch: {
-    // This test is known to generate incorrect code for screw_ie8=false.
-    // Update expected result in the event this bug is ever fixed.
     options = { screw_ie8: false };
     mangle = { screw_ie8: false };
     beautify = { screw_ie8: false };
@@ -64,11 +82,11 @@ dont_screw_try_catch: {
     }
     expect: {
         bad = function(n){
-            return function(n){
+            return function(t){
                 try{
-                    t()
-                } catch(t) {
-                    n(t)
+                    n()
+                } catch(n) {
+                    t(n)
                 }
             }
         };
@@ -104,8 +122,6 @@ do_screw_try_catch_undefined: {
 }
 
 dont_screw_try_catch_undefined: {
-    // This test is known to generate incorrect code for screw_ie8=false.
-    // Update expected result in the event this bug is ever fixed.
     options = { screw_ie8: false };
     mangle = { screw_ie8: false };
     beautify = { screw_ie8: false };
@@ -121,14 +137,84 @@ dont_screw_try_catch_undefined: {
         };
     }
     expect: {
-        function a(o){
+        function a(n){
             try{
                 throw "Stuff"
-            } catch (n) {
-                console.log("caught: "+n)
+            } catch (undefined) {
+                console.log("caught: " + undefined)
             }
-            console.log("undefined is " + n);
-            return o === n
+            console.log("undefined is " + undefined);
+            return n === undefined
         }
     }
 }
+
+reduce_vars: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        screw_ie8: false,
+        unused: true,
+    }
+    mangle = {
+        screw_ie8: false,
+    }
+    input: {
+        function f() {
+            var a;
+            try {
+                x();
+            } catch (a) {
+                y();
+            }
+            alert(a);
+        }
+    }
+    expect: {
+        function f() {
+            var t;
+            try {
+                x();
+            } catch (t) {
+                y();
+            }
+            alert(t);
+        }
+    }
+}
+
+issue_1586_1: {
+    options = {
+        screw_ie8: false,
+    }
+    mangle = {
+        screw_ie8: false,
+    }
+    input: {
+        function f() {
+            try {
+            } catch (err) {
+                console.log(err.message);
+            }
+        }
+    }
+    expect_exact: "function f(){try{}catch(c){console.log(c.message)}}"
+}
+
+issue_1586_2: {
+    options = {
+        screw_ie8: true,
+    }
+    mangle = {
+        screw_ie8: true,
+    }
+    input: {
+        function f() {
+            try {
+            } catch (err) {
+                console.log(err.message);
+            }
+        }
+    }
+    expect_exact: "function f(){try{}catch(c){console.log(c.message)}}"
+}
diff --git a/test/compress/sequences.js b/test/compress/sequences.js
index d93f5237..41cfc726 100644
--- a/test/compress/sequences.js
+++ b/test/compress/sequences.js
@@ -248,6 +248,39 @@ iife: {
     }
     expect: {
         x = 42, function a() {}(), function b() {}(), function c() {}(),
-        function d() {}(), function e() {}(), function f() {}(), function g() {}()
+        function d() {}(), function e() {}(), function f() {}(), function g() {}();
+    }
+}
+
+unsafe_undefined: {
+    options = {
+        conditionals: true,
+        if_return: true,
+        sequences: true,
+        side_effects: true,
+        unsafe: true,
+    }
+    input: {
+        function f(undefined) {
+            if (a)
+                return b;
+            if (c)
+                return d;
+        }
+        function g(undefined) {
+            if (a)
+                return b;
+            if (c)
+                return d;
+            e();
+        }
+    }
+    expect: {
+        function f(undefined) {
+            return a ? b : c ? d : undefined;
+        }
+        function g(undefined) {
+            return a ? b : c ? d : void e();
+        }
     }
 }
diff --git a/test/compress/transform.js b/test/compress/transform.js
new file mode 100644
index 00000000..7b616e40
--- /dev/null
+++ b/test/compress/transform.js
@@ -0,0 +1,129 @@
+booleans_evaluate: {
+    options = {
+        booleans: true,
+        evaluate: true,
+    }
+    input: {
+        console.log(typeof void 0 != "undefined");
+        console.log(1 == 1, 1 === 1)
+        console.log(1 != 1, 1 !== 1)
+    }
+    expect: {
+        console.log(!1);
+        console.log(!0, !0);
+        console.log(!1, !1);
+    }
+}
+
+booleans_global_defs: {
+    options = {
+        booleans: true,
+        evaluate: true,
+        global_defs: {
+            A: true,
+        },
+    }
+    input: {
+        console.log(A == 1);
+    }
+    expect: {
+        console.log(!0);
+    }
+}
+
+condition_evaluate: {
+    options = {
+        booleans: true,
+        dead_code: false,
+        evaluate: true,
+        loops: false,
+    }
+    input: {
+        while (1 === 2);
+        for (; 1 == true;);
+        if (void 0 == null);
+    }
+    expect: {
+        while (!1);
+        for (; !0;);
+        if (!0);
+    }
+}
+
+if_else_empty: {
+    options = {
+        conditionals: true,
+    }
+    input: {
+        if ({} ? a : b); else {}
+    }
+    expect: {
+        !{} ? b : a;
+    }
+}
+
+label_if_break: {
+    options = {
+        conditionals: true,
+        dead_code: true,
+        evaluate: true,
+    }
+    input: {
+        L: if (true) {
+            a;
+            break L;
+        }
+    }
+    expect: {
+        a;
+    }
+}
+
+while_if_break: {
+    options = {
+        conditionals: true,
+        loops: true,
+        sequences: true,
+    }
+    input: {
+        while (a) {
+            if (b) if(c) d;
+            if (e) break;
+        }
+    }
+    expect: {
+        for(; a && (b && c && d, !e););
+    }
+}
+
+if_return: {
+    options = {
+        booleans: true,
+        conditionals: true,
+        if_return: true,
+        sequences: true,
+    }
+    input: {
+        function f(w, x, y, z) {
+            if (x) return;
+            if (w) {
+                if (y) return;
+            } else if (z) return;
+            if (x == y) return true;
+
+            if (x) w();
+            if (y) z();
+            return true;
+        }
+    }
+    expect: {
+        function f(w, x, y, z) {
+            if (!x) {
+                if (w) {
+                    if (y) return;
+                } else if (z) return;
+                return x == y || (x && w(), y && z(), !0);
+            }
+        }
+    }
+}
diff --git a/test/input/invalid/loop-no-body.js b/test/input/invalid/loop-no-body.js
new file mode 100644
index 00000000..07b27428
--- /dev/null
+++ b/test/input/invalid/loop-no-body.js
@@ -0,0 +1 @@
+for (var i = 0; i < 1; i++) 
diff --git a/test/mocha/cli.js b/test/mocha/cli.js
index c07eeee7..2b44c901 100644
--- a/test/mocha/cli.js
+++ b/test/mocha/cli.js
@@ -82,7 +82,7 @@ describe("bin/uglifyjs", function () {
        });
     });
     it("Should work with --keep-fnames (mangle & compress)", function (done) {
-       var command = uglifyjscmd + ' test/input/issue-1431/sample.js --keep-fnames -m -c';
+       var command = uglifyjscmd + ' test/input/issue-1431/sample.js --keep-fnames -m -c unused=false';
 
        exec(command, function (err, stdout) {
            if (err) throw err;
@@ -152,7 +152,7 @@ describe("bin/uglifyjs", function () {
        });
     });
     it("Should process inline source map", function(done) {
-        var command = uglifyjscmd + ' test/input/issue-520/input.js -cm toplevel --in-source-map inline --source-map-inline';
+        var command = uglifyjscmd + ' test/input/issue-520/input.js -mc toplevel --in-source-map inline --source-map-inline';
 
         exec(command, function (err, stdout) {
             if (err) throw err;
@@ -238,4 +238,17 @@ describe("bin/uglifyjs", function () {
             done();
         });
     });
+    it("Should fail with a missing loop body", function(done) {
+        var command = uglifyjscmd + ' test/input/invalid/loop-no-body.js';
+
+        exec(command, function (err, stdout, stderr) {
+            assert.ok(err);
+            var lines = stderr.split(/\n/);
+            assert.strictEqual(lines[0], "Parse error at test/input/invalid/loop-no-body.js:2,0");
+            assert.strictEqual(lines[1], "for (var i = 0; i < 1; i++) ");
+            assert.strictEqual(lines[2], "                            ^");
+            assert.strictEqual(lines[3], "SyntaxError: Unexpected token: eof (undefined)");
+            done();
+        });
+    });
 });
diff --git a/test/mocha/comment-filter.js b/test/mocha/comment-filter.js
index 01580c87..9474e732 100644
--- a/test/mocha/comment-filter.js
+++ b/test/mocha/comment-filter.js
@@ -72,4 +72,12 @@ describe("comment filters", function() {
         assert.strictEqual(UglifyJS.parse("/* ok */ function a(){}").print_to_string(options), "/* ok */function a(){}");
         assert.strictEqual(UglifyJS.parse("/* ok */ function a(){}").print_to_string(options), "/* ok */function a(){}");
     });
+
+    it("Should handle shebang and preamble correctly", function() {
+        var code = UglifyJS.minify("#!/usr/bin/node\nvar x = 10;", {
+            fromString: true,
+            output: { preamble: "/* Build */" }
+        }).code;
+        assert.strictEqual(code, "#!/usr/bin/node\n/* Build */\nvar x=10;");
+    })
 });
diff --git a/test/mocha/glob.js b/test/mocha/glob.js
index c2fc9464..30313656 100644
--- a/test/mocha/glob.js
+++ b/test/mocha/glob.js
@@ -3,17 +3,13 @@ var assert = require("assert");
 
 describe("minify() with input file globs", function() {
     it("minify() with one input file glob string.", function() {
-        var result = Uglify.minify("test/input/issue-1242/foo.*", {
-            compress: { collapse_vars: true }
-        });
+        var result = Uglify.minify("test/input/issue-1242/foo.*");
         assert.strictEqual(result.code, 'function foo(o){print("Foo:",2*o)}var print=console.log.bind(console);');
     });
     it("minify() with an array of one input file glob.", function() {
         var result = Uglify.minify([
             "test/input/issue-1242/b*.es5",
-        ], {
-            compress: { collapse_vars: true }
-        });
+        ]);
         assert.strictEqual(result.code, 'function bar(n){return 3*n}function baz(n){return n/2}');
     });
     it("minify() with an array of multiple input file globs.", function() {
@@ -21,8 +17,8 @@ describe("minify() with input file globs", function() {
             "test/input/issue-1242/???.es5",
             "test/input/issue-1242/*.js",
         ], {
-            compress: { collapse_vars: true }
+            compress: { toplevel: true }
         });
-        assert.strictEqual(result.code, 'function bar(n){return 3*n}function baz(n){return n/2}function foo(n){print("Foo:",2*n)}var print=console.log.bind(console);print("qux",bar(3),baz(12)),foo(11);');
+        assert.strictEqual(result.code, 'var print=console.log.bind(console);print("qux",function(n){return 3*n}(3),function(n){return n/2}(12)),function(n){print("Foo:",2*n)}(11);');
     });
 });
diff --git a/test/mocha/minify.js b/test/mocha/minify.js
index 51c46b28..a4587cb7 100644
--- a/test/mocha/minify.js
+++ b/test/mocha/minify.js
@@ -78,6 +78,7 @@ describe("minify", function() {
         });
         it("Should process inline source map", function() {
             var code = Uglify.minify("./test/input/issue-520/input.js", {
+                compress: { toplevel: true },
                 inSourceMap: "inline",
                 sourceMapInline: true
             }).code + "\n";
diff --git a/test/mocha/release.js b/test/mocha/release.js
new file mode 100644
index 00000000..3b2d9a72
--- /dev/null
+++ b/test/mocha/release.js
@@ -0,0 +1,54 @@
+var assert = require("assert");
+var spawn = require("child_process").spawn;
+
+if (!process.env.UGLIFYJS_TEST_ALL) return;
+
+function run(command, args, done) {
+    var id = setInterval(function() {
+        process.stdout.write("\0");
+    }, 5 * 60 * 1000);
+    spawn(command, args, {
+        stdio: "ignore"
+    }).on("exit", function(code) {
+        clearInterval(id);
+        assert.strictEqual(code, 0);
+        done();
+    });
+}
+
+describe("test/benchmark.js", function() {
+    this.timeout(5 * 60 * 1000);
+    [
+        "-b",
+        "-b bracketize",
+        "-m",
+        "-mc passes=3",
+        "-mc passes=3,toplevel",
+        "-mc passes=3,unsafe",
+        "-mc keep_fargs=false,passes=3",
+        "-mc keep_fargs=false,passes=3,pure_getters,unsafe,unsafe_comps,unsafe_math,unsafe_proto",
+    ].forEach(function(options) {
+        it("Should pass with options " + options, function(done) {
+            var args = options.split(/ /);
+            args.unshift("test/benchmark.js");
+            run(process.argv[0], args, done);
+        });
+    });
+});
+
+describe("test/jetstream.js", function() {
+    this.timeout(20 * 60 * 1000);
+    it("Should install phantomjs-prebuilt", function(done) {
+        run("npm", ["install", "phantomjs-prebuilt@2.1.14"], done);
+    });
+    [
+        "-mc warnings=false",
+        "-mc keep_fargs=false,passes=3,pure_getters,unsafe,unsafe_comps,unsafe_math,unsafe_proto,warnings=false",
+    ].forEach(function(options) {
+        it("Should pass with options " + options, function(done) {
+            var args = options.split(/ /);
+            args.unshift("test/jetstream.js");
+            run(process.argv[0], args, done);
+        });
+    });
+});
diff --git a/test/run-tests.js b/test/run-tests.js
index 15a12c6b..898bb793 100755
--- a/test/run-tests.js
+++ b/test/run-tests.js
@@ -6,6 +6,7 @@ var U = require("../tools/node");
 var path = require("path");
 var fs = require("fs");
 var assert = require("assert");
+var vm = require("vm");
 
 var tests_dir = path.dirname(module.filename);
 var failures = 0;
@@ -165,6 +166,51 @@ function run_compress_tests() {
                         failed_files[file] = 1;
                     }
                 }
+                if (test.expect_stdout) {
+                    try {
+                        var stdout = run_code(input_code);
+                        if (test.expect_stdout === true) {
+                            test.expect_stdout = stdout;
+                        }
+                        if (test.expect_stdout != stdout) {
+                            log("!!! Invalid input or expected stdout\n---INPUT---\n{input}\n---EXPECTED STDOUT---\n{expected}\n---ACTUAL STDOUT---\n{actual}\n\n", {
+                                input: input_code,
+                                expected: test.expect_stdout,
+                                actual: stdout,
+                            });
+                            failures++;
+                            failed_files[file] = 1;
+                        } else {
+                            try {
+                                stdout = run_code(output);
+                                if (test.expect_stdout != stdout) {
+                                    log("!!! failed\n---INPUT---\n{input}\n---EXPECTED STDOUT---\n{expected}\n---ACTUAL STDOUT---\n{actual}\n\n", {
+                                        input: input_code,
+                                        expected: test.expect_stdout,
+                                        actual: stdout,
+                                    });
+                                    failures++;
+                                    failed_files[file] = 1;
+                                }
+                            } catch (ex) {
+                                log("!!! Execution of output failed\n---INPUT---\n{input}\n---OUTPUT---\n{output}\n--ERROR--\n{error}\n\n", {
+                                    input: input_code,
+                                    output: output,
+                                    error: ex.toString(),
+                                });
+                                failures++;
+                                failed_files[file] = 1;
+                            }
+                        }
+                    } catch (ex) {
+                        log("!!! Execution of input failed\n---INPUT---\n{input}\n--ERROR--\n{error}\n\n", {
+                            input: input_code,
+                            error: ex.toString(),
+                        });
+                        failures++;
+                        failed_files[file] = 1;
+                    }
+                }
             }
         }
         var tests = parse_test(path.resolve(dir, file));
@@ -214,6 +260,23 @@ function parse_test(file) {
         }));
     }
 
+    function read_string(stat) {
+        if (stat.TYPE == "SimpleStatement") {
+            var body = stat.body;
+            switch(body.TYPE) {
+              case "String":
+                return body.value;
+              case "Array":
+                return body.elements.map(function(element) {
+                    if (element.TYPE !== "String")
+                        throw new Error("Should be array of strings");
+                    return element.value;
+                }).join("\n");
+            }
+        }
+        throw new Error("Should be string or array of strings");
+    }
+
     function get_one_test(name, block) {
         var test = { name: name, options: {} };
         var tw = new U.TreeWalker(function(node, descend){
@@ -226,12 +289,13 @@ function parse_test(file) {
                 return true;
             }
             if (node instanceof U.AST_LabeledStatement) {
+                var label = node.label;
                 assert.ok(
-                    ["input", "expect", "expect_exact", "expect_warnings"].indexOf(node.label.name) >= 0,
+                    ["input", "expect", "expect_exact", "expect_warnings", "expect_stdout"].indexOf(label.name) >= 0,
                     tmpl("Unsupported label {name} [{line},{col}]", {
-                        name: node.label.name,
-                        line: node.label.start.line,
-                        col: node.label.start.col
+                        name: label.name,
+                        line: label.start.line,
+                        col: label.start.col
                     })
                 );
                 var stat = node.body;
@@ -239,15 +303,16 @@ function parse_test(file) {
                     if (stat.body.length == 1) stat = stat.body[0];
                     else if (stat.body.length == 0) stat = new U.AST_EmptyStatement();
                 }
-                if (node.label.name === "expect_exact") {
-                    if (!(stat.TYPE === "SimpleStatement" && stat.body.TYPE === "String")) {
-                        throw new Error(
-                            "The value of the expect_exact clause should be a string, " +
-                            "like `expect_exact: \"some.exact.javascript;\"`");
+                if (label.name == "expect_exact") {
+                    test[label.name] = read_string(stat);
+                } else if (label.name == "expect_stdout") {
+                    if (stat.TYPE == "SimpleStatement" && stat.body instanceof U.AST_Boolean) {
+                        test[label.name] = stat.body.value;
+                    } else {
+                        test[label.name] = read_string(stat) + "\n";
                     }
-                    test[node.label.name] = stat.body.start.value
                 } else {
-                    test[node.label.name] = stat;
+                    test[label.name] = stat;
                 }
                 return true;
             }
@@ -269,3 +334,17 @@ function evaluate(code) {
         code = make_code(code, { beautify: true });
     return new Function("return(" + code + ")")();
 }
+
+function run_code(code) {
+    var stdout = "";
+    var original_write = process.stdout.write;
+    process.stdout.write = function(chunk) {
+        stdout += chunk;
+    };
+    try {
+        new vm.Script(code).runInNewContext({ console: console }, { timeout: 5000 });
+        return stdout;
+    } finally {
+        process.stdout.write = original_write;
+    }
+}