Further analysis required. This may be a non-trivial peephole optimization, i.e., there is a semantic difference between the request time and "now".
agreed, please don't create tickets like this in next roadmap if there is no patch attached; that's OK if it's justified and a patch is there. thanks!
note: in php 5.4.0 alpha 1, $_SERVER['REQUEST_TIME'] was changed to include microsecond precision.