diff --git a/src/Php/Constants.php b/src/Php/Constants.php
index 2fca7b6f..1b41e3de 100644
--- a/src/Php/Constants.php
+++ b/src/Php/Constants.php
@@ -59,7 +59,6 @@ class Constants
     public const UNSUPPORTED_FUNCTIONS = [
         'compact',
         'extract',
-        'func_num_args',
         'func_get_arg',
         'func_get_args',
     ];
diff --git a/src/Php/FuncCallOptimizer.php b/src/Php/FuncCallOptimizer.php
index be16620b..c1b330fa 100644
--- a/src/Php/FuncCallOptimizer.php
+++ b/src/Php/FuncCallOptimizer.php
@@ -56,6 +56,18 @@ trait FuncCallOptimizer
         if ($name === 'array_key_exists') {
             return $getArg(1) . '.offsetExists(' . $getArg(0) . ')';
         }
+        if ($name === 'func_get_args') {
+
+        }
+        if ($name === 'func_num_args') {
+            $funcDef = $this->functionDef;
+            foreach ($funcDef->argInfoList as $i => $argInfo) {
+                if ($argInfo->variadic) {
+                    return '(' . $argInfo->name . '.count() + ' . $i . ')';
+                }
+            }
+            return count($funcDef->argInfoList);
+        }
         if ($name === 'function_exists') {
             $funcName = $expr->args[0]->value;
             if ($this->isScalarString($funcName)) {
diff --git a/tests/aot/functions/func_num_args.phpt b/tests/aot/functions/func_num_args.phpt
new file mode 100644
index 00000000..d0650222
--- /dev/null
+++ b/tests/aot/functions/func_num_args.phpt
@@ -0,0 +1,29 @@
+--TEST--
+func_num_args
+--FILE--
+<?php
+
+function foo1($a, $b, $c = 10)
+{
+    var_dump(func_num_args());
+}
+
+function foo2(...$args) {
+    var_dump(func_num_args());
+}
+
+function foo3($a, $b, $c, ...$args) {
+    var_dump(func_num_args());
+}
+
+function main()
+{
+   foo1(2.5, 3);
+   foo2(1, 3, 5, 8, 10);
+   foo3(1, 3, 5, 8, 10, 12);
+}
+?>
+--EXPECT--
+int(3)
+int(5)
+int(6)
\ No newline at end of file