$re = '/\w+\s*=\s*(?:"[^"\n]*(?:"|$)|\S+(?=,|$))/m';
$str = 'Include="All Violations", CheckType=MaxTrans
MetricName = PlacedInstances, PlacedOnly = 1
CheckType=Hold, Include="reg2reg,in2reg,in2out,reg2out"
CheckType=Setup, Include="reg2reg,in2reg,in2out,reg2out
MetricName = PlacedInstances, PlacedOnly = 1, PlacedOnly = 1';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php