<?php

/**
 * PHP 5.6.29
 */

var_dump( ~PHP_INT_MAX < -PHP_INT_MAX ); // bool(true)
var_dump( ~PHP_INT_MAX > -PHP_INT_MAX ); // bool(false)

// ksort()
$array = [ -PHP_INT_MAX => 'bar', ~PHP_INT_MAX => 'foo', 0 => 'baz' ];
ksort( $array );
/*
Array
(
    [-9223372036854775808] => foo
    [-9223372036854775807] => bar
    [0] => baz
)
*/

// ksort() with SORT_NUMERIC
$array = [ -PHP_INT_MAX => 'bar', ~PHP_INT_MAX => 'foo', 0 => 'baz' ];
ksort( $array, SORT_NUMERIC );
/*
Array
(
    [-9223372036854775807] => bar <------ WRONG!
    [-9223372036854775808] => foo
    [0] => baz
)
*/

/**
 * PHP 7.0.14
 */

var_dump( ~PHP_INT_MAX < -PHP_INT_MAX ); // bool(true)
var_dump( ~PHP_INT_MAX > -PHP_INT_MAX ); // bool(false)

// ksort()
$array = [ -PHP_INT_MAX => 'bar', ~PHP_INT_MAX => 'foo', 0 => 'baz' ];
ksort( $array );
/*
Array
(
    [-9223372036854775808] => foo
    [-9223372036854775807] => bar
    [0] => baz
)
*/

// ksort() with SORT_NUMERIC
$array = [ -PHP_INT_MAX => 'bar', ~PHP_INT_MAX => 'foo', 0 => 'baz' ];
ksort( $array, SORT_NUMERIC );
/*
Array
(
    [-9223372036854775808] => foo
    [-9223372036854775807] => bar
    [0] => baz
)
*/