>>> +# nested likely/unlikely calls >>> + if ($line =~ /\b(?:(?:un)?likely)\s*\(\s*!?\s*(IS_ERR(?:_OR_NULL|_VALUE)?|WARN)/) { >>> + WARN("LIKELY_MISUSE", >> >> How do you think about to use the specification “(?:IS_ERR(?:_(?:OR_NULL|VALUE))?|WARN)” >> in this regular expression? … > IS_ERR > (?:_ <- Another atomic group just to show that '_' is a common prefix? Yes. - I hope that this specification detail can help a bit. > Usually, Perl interpreter is very good at optimizing such things. Would you like to help this software component by omitting a pair of non-capturing parentheses at the beginning? \b(?:un)?likely\s* Regards, Markus