diff --git a/examples/micro_bench.php b/examples/micro_bench.php
index b20d0d53..a35288d7 100644
--- a/examples/micro_bench.php
+++ b/examples/micro_bench.php
@@ -16,9 +16,10 @@ function simpleudcall($n) {
 function hallo2() {
 }
 
-function simpleicall($n) {
-  for ($i = 0; $i < $n; $i++)
-    $ret = function_exists('hallo');
+function simpleicall($n)
+{
+    for ($i = 0; $i < $n; $i++)
+        $ret = function_exists('hallo');
 }
 
 class Foo {
@@ -287,14 +288,14 @@ function main()
     empty_loop(N);
     $t = end_test($t, 'empty_loop');
     $overhead = $last_time;
-//    simpleucall(N);
-//    $t = end_test($t, 'func()', $overhead);
-//    simpleudcall(N);
-//    $t = end_test($t, 'undef_func()', $overhead);
+    simpleucall(N);
+    $t = end_test($t, 'func()', $overhead);
+    simpleudcall(N);
+    $t = end_test($t, 'undef_func()', $overhead);
     simpleicall(N);
     $t = end_test($t, 'int_func()', $overhead);
-//    Foo::read_static(N);
-//    $t = end_test($t, '$x = self::$x', $overhead);
+    Foo::read_static(N);
+    $t = end_test($t, '$x = self::$x', $overhead);
 //    Foo::write_static(N);
 //    $t = end_test($t, 'self::$x = 0', $overhead);
 //    Foo::isset_static(N);
diff --git a/src/Php/CompilerBase.php b/src/Php/CompilerBase.php
index d17b0ced..4c386efa 100644
--- a/src/Php/CompilerBase.php
+++ b/src/Php/CompilerBase.php
@@ -763,7 +763,6 @@ class CompilerBase extends \PhpAot\Core\Translator
                 if (!$this->isVarExpr($expr->var)) {
                     $this->fatalError($expr, 'When an assignment expression serves as an rvalue, it must be an assignment of a variable');
                 }
-
                 return $this->parseExpr($expr);
             default:
                 return $this->parseExpr($expr);
diff --git a/src/Php/FuncCallOptimizer.php b/src/Php/FuncCallOptimizer.php
index f1f95807..68276547 100644
--- a/src/Php/FuncCallOptimizer.php
+++ b/src/Php/FuncCallOptimizer.php
@@ -45,7 +45,13 @@ trait FuncCallOptimizer
             return 'php::math::abs(' . $this->parseIdentifier($expr->args[0]->value) . ')';
         }
         if ($name === 'function_exists') {
-            return 'php::fn::function_exists(' . $this->parseIdentifier($expr->args[0]->value) . ')';
+            $funcName = $expr->args[0]->value;
+            if ($this->isScalarString($funcName)) {
+                $funcName = $this->getLiteralString(strtolower(trim($funcName->value, '\\')));
+                return 'php::fn::function_exists(' . $funcName . ', true)';
+            } else {
+                return 'php::fn::function_exists(' . $this->parseIdentifier($funcName) . ')';
+            }
         }
 
         return false;