Re: [RFC] [VOTE] Constant scalar expressions

Am 20.11.2013 um 21:06 schrieb Yasuo Ohgaki <yohgaki@ohgaki.net>: > Hi Bob, > > On Thu, Nov 21, 2013 at 1:54 AM, Bob Weinand <bobwei9@hotmail.com> wrote: > >> I just have moved the RFC to vote as there was no negative feedback nor >> unresolved issues. >> >> Find the vote (and the RFC) at: >> >> https://wiki.php.net/rfc/const_scalar_exprs#vote >> >> Vote will last for one week. >> > > It's nice feature, but I concerned about op caching. > Currently, const is "constant". Therefore, constant value can be cached > (i.e. hard coded in ops) > > This feature seems break op caching (or close the door for constant > optimization at least) > > Is this a issue? I would like hear opinions from opcache/apc developers. > > Regards, > > -- > Yasuo Ohgaki > yohgaki@ohgaki.net As noted in the RFC "The patch is ready to be merged. (Opcache support is included, thanks to Dmitry)". So, Dmitry already did the patch for opcache and I assume he has done the best possible for that. Btw. opcache doesn't affect constants if I'm not wrong, because, what would you optimize here (already possible): a.php: if ($argv[1] == "include") include 'b.php'; const B = A; b.php: const A = 10; Here we can't cache anything because the constant B depends on a conditional inclusion: same problem. It's that same way resolved with the current patch. Also constant expressions (like 2+2 without constants involved) are resolved at compile time. So I can't detect any impact related to opcache. Bob