diff --git a/examples/micro_bench.php b/examples/micro_bench.php
index 325b6a1b..a14d629c 100644
--- a/examples/micro_bench.php
+++ b/examples/micro_bench.php
@@ -18,8 +18,10 @@ function hallo2() {
 
 function simpleicall($n)
 {
-    for ($i = 0; $i < $n; $i++)
-        $ret = function_exists('hallo');
+    for ($i = 0; $i < $n; $i++) {
+//        $ret = function_exists('hallo');
+        $ret = class_exists('Foo2');
+    }
 }
 
 class Foo {
@@ -169,7 +171,6 @@ function create_object($n) {
 
 function read_const($n) {
     for ($i = 0; $i < $n; ++$i) {
-//        $x = TEST;
         $x = TEST_CONST_2;
     }
 }
@@ -280,11 +281,11 @@ function total()
 
 const N = 5000000;
 const TEST = null;
+const TEST_CONST_2 = 1999;
 
 function main()
 {
     global $total, $last_time, $g_var;
-    define('TEST_CONST_2', 1999);
     $g_var = 0;
     $t0 = $t = start_test();
     empty_loop(N);
diff --git a/src/Php/FuncCallOptimizer.php b/src/Php/FuncCallOptimizer.php
index 8490e90e..b3787be2 100644
--- a/src/Php/FuncCallOptimizer.php
+++ b/src/Php/FuncCallOptimizer.php
@@ -109,6 +109,18 @@ trait FuncCallOptimizer
         if ($name === 'function_exists') {
             return $this->genFunctionExists($name, $expr);
         }
+        if ($name === 'class_exists') {
+            $className = $expr->args[0]->value;
+            if ($this->isScalarString($className) and $this->hasClass($className->value)) {
+                return 'true';
+            }
+        }
+        if ($name === 'get_class') {
+            $object = $expr->args[0]->value;
+            if ($this->isVarExpr($object) and $this->isTypedObject($object->name)) {
+                return $this->genCharPtr($this->getObjectType($object->name));
+            }
+        }
         return false;
     }
 
@@ -128,9 +140,15 @@ trait FuncCallOptimizer
     {
         $funcName = $expr->args[0]->value;
         if ($this->isScalarString($funcName)) {
-            $funcName = $this->getLiteralString(strtolower(trim($funcName->value, '\\')));
+            $nameLower = strtolower(trim($funcName->value, '\\'));
+            if ($this->findNativeFunction($nameLower)) {
+                return 'true';
+            }
+            $funcName = $this->getLiteralString($nameLower);
             return 'php::fn::function_exists(' . $funcName . ', true)';
         }
         return 'php::fn::function_exists(' . $this->parseIdentifier($funcName) . ')';
     }
+
+
 }
diff --git a/tests/aot/functions/get_class.phpt b/tests/aot/functions/get_class.phpt
new file mode 100644
index 00000000..141e8683
--- /dev/null
+++ b/tests/aot/functions/get_class.phpt
@@ -0,0 +1,17 @@
+--TEST--
+class const 001
+--FILE--
+<?php
+class Worker
+{
+    public const BAR = "string constant";
+}
+
+function main()
+{
+    $o = new Worker;
+    var_dump(get_class($o));
+}
+?>
+--EXPECT--
+string(6) "Worker"
\ No newline at end of file