replace single-use recursive functions (#2659)

fixes #2628

1 files changed, 29 insertions, 10 deletions

diff --git a/lib/compress.js b/lib/compress.js
index bb355423..d890caf7 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -319,6 +319,7 @@ merge(Compressor.prototype, {
             } else {
                 def.fixed = false;
             }
+            def.recursive_refs = 0;
             def.references = [];
             def.should_replace = undefined;
             def.single_use = undefined;
@@ -369,7 +370,7 @@ merge(Compressor.prototype, {
             return compressor.option("unused")
                 && !def.scope.uses_eval
                 && !def.scope.uses_with
-                && def.references.length == 1
+                && def.references.length - def.recursive_refs == 1
                 && tw.loop_ids[def.id] === tw.in_loop;
         }
 
@@ -621,7 +622,9 @@ merge(Compressor.prototype, {
                 d.fixed = false;
             } else if (d.fixed) {
                 value = this.fixed_value();
-                if (value && ref_once(tw, compressor, d)) {
+                if (value instanceof AST_Lambda && recursive_ref(tw, d)) {
+                    d.recursive_refs++;
+                } else if (value && ref_once(tw, compressor, d)) {
                     d.single_use = value instanceof AST_Lambda
                         || d.scope === this.scope && value.is_constant_expression();
                 } else {
@@ -4670,17 +4673,18 @@ merge(Compressor.prototype, {
             if (fixed instanceof AST_Defun) {
                 d.fixed = fixed = make_node(AST_Function, fixed, fixed);
             }
-            if (d.single_use && fixed instanceof AST_Function) {
+            var single_use = d.single_use;
+            if (single_use && fixed instanceof AST_Function) {
                 if (d.scope !== self.scope
                     && (!compressor.option("reduce_funcs")
                         || d.escaped == 1
                         || fixed.inlined)) {
-                    d.single_use = false;
+                    single_use = false;
                 } else if (recursive_ref(compressor, d)) {
-                    d.single_use = false;
+                    single_use = false;
                 } else if (d.scope !== self.scope || d.orig[0] instanceof AST_SymbolFunarg) {
-                    d.single_use = fixed.is_constant_expression(self.scope);
-                    if (d.single_use == "f") {
+                    single_use = fixed.is_constant_expression(self.scope);
+                    if (single_use == "f") {
                         var scope = self.scope;
                         do {
                             if (scope instanceof AST_Defun || scope instanceof AST_Function) {
@@ -4690,9 +4694,24 @@ merge(Compressor.prototype, {
                     }
                 }
             }
-            if (d.single_use && fixed) {
-                var value = fixed.optimize(compressor);
-                return value === fixed ? fixed.clone(true) : value;
+            if (single_use && fixed) {
+                var value;
+                if (d.recursive_refs > 0 && fixed.name instanceof AST_SymbolDefun) {
+                    value = fixed.clone(true);
+                    var defun_def = value.name.definition();
+                    value.name = make_node(AST_SymbolLambda, value.name, value.name);
+                    value.name.scope = value;
+                    var lambda_def = value.def_function(value.name);
+                    value.walk(new TreeWalker(function(node) {
+                        if (node instanceof AST_SymbolRef && node.definition() === defun_def) {
+                            node.thedef = lambda_def;
+                        }
+                    }));
+                } else {
+                    value = fixed.optimize(compressor);
+                    if (value === fixed) value = fixed.clone(true);
+                }
+                return value;
             }
             if (fixed && d.should_replace === undefined) {
                 var init;