Opcode Descriptions and Examples
PHP Manual

POST_INC

PHP code

<?php
/*
 * increments variable indicated by value1 by 1 (after performing other operations) and stores in result
 * opcode number: 36
 */
$a++;
?>

PHP opcodes

Function name: (null)

Compiled variables: !0=$a

line#op fetchextreturn operands
60 POST_INC   ~0 !0
 1 FREE     ~0
72 RETURN     1

Opcode Descriptions and Examples
PHP Manual