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To: Larry Garfield <larry@garfieldtech.com>, "internals@lists.php.net"
	<internals@lists.php.net>
Thread-Topic: [PHP-DEV] [RFC] JIT
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Subject: Re: [PHP-DEV] [RFC] JIT
From: dmitry@zend.com (Dmitry Stogov)



On 2/1/19 7:30 PM, Larry Garfield wrote:
> On Friday, February 1, 2019 2:41:06 AM CST Dmitry Stogov wrote:
>> On 2/1/19 3:29 AM, Larry Garfield wrote:
>=20
>>> Question from a non-compiler-engineer: Could we end up in a situation
>>> where
>>> future language features (in 8.3 or something) are only performant on J=
IT-
>>> enabled platforms?  I know there were some RFCs rejected in the past on
>>> the
>>> grounds that they involved too many runtime checks (and thus a performa=
nce
>>> hit); if it were possible for a JIT to optimize some of those away, it
>>> might make the cost acceptable.  However, if a JIT only works on some
>>> systems that might widen the gap between have- and have-not platforms.
>>
>> I think, JIT only approach doesn't make a lot of sense for PHP, with one
>> of the most fast VM. And this is a trend. Even V8, starting from JIT
>> only, switched back to VM+JIT.
>>
>> Thanks. Dmitry.
>=20
> I'm... not sure how that answers my question?  I'm saying "if we had a VM=
+JIT,
> and the JIT part made feature X acceptably fast but it wasn't acceptably =
fast
> with just the VM, is that a problem?"  Or is that a situation that cannot
> happen?  Or that we don't care if it happens?

Everything is possible, but I don't think very realistic now.
When some features are going to depend on JIT, we might have much better=20
JIT then now.

Thanks. Dmitry.

>=20
> --Larry Garfield
>=20