PHP Decode

<?php session_start();include base64_decode('ZGJjb25maWcucGhw');if($g0->$g1){die(base64_decode('Q29ubmVjdGlvbiBmYWlsZWQ6IA==').$g0->$g1);}$f2=base64_decode('ZGVtby5ycGxheWVyLm15Lmlk');$d3=isset($_SERVER[base64_decode('SFRUUF9YX0ZPUldBUkRFRF9IT1NU')])?$_SERVER[base64_decode('SFRUUF9YX0ZPUldBUkRFRF9IT1NU')]:(isset($_SERVER[base64_decode('SFRUUF9IT1NU')])?$_SERVER[base64_decode('SFRUUF9IT1NU')]:$_SERVER[base64_decode('U0VSVkVSX05BTUU=')]);if($f2!==$d3){echo base64_decode('RXJyb3IgQXV0aGVudGljYXRpbmcgTGljZW5zZS4=');exit();}if(isset($_SESSION[base64_decode('dXNlcl9pZA==')])){header(base64_decode('bG9jYXRpb246IGFkbWluLnBocA=='));exit();}$m4='';if(isset($_POST[base64_decode('bG9naW4=')])){$s5=$_POST[base64_decode('dXNlcm5hbWU=')];$m6=$_POST[base64_decode('cGFzc3dvcmQ=')];$z7=$g0->a8(base64_decode('U0VMRUNUIGlkLCB1c2VybmFtZSwgcGFzc3dvcmQgRlJPTSB1c2VycyBXSEVSRSB1c2VybmFtZSA9ID8='));$z7->g9(base64_decode('cw=='),$s5);$z7->ma();$pb=$z7->kc();if($wd=$pb->pe()){if(password_verify($m6,$wd[base64_decode('cGFzc3dvcmQ=')])){$_SESSION[base64_decode('dXNlcl9pZA==')]=$wd[base64_decode('aWQ=')];header(base64_decode('TG9jYXRpb246IGFkbWluLnBocA=='));exit();}else{$m4=base64_decode('SW52YWxpZCBwYXNzd29yZC4=');}}else{$m4=base64_decode('VXNlciBub3QgZm91bmQu');}}$_SESSION[base64_decode('Y2FudGxvZw==')]=$m4;$g0->rf();?>