Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:83557
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain gmail.com designates 209.85.192.50 as permitted sender)
MIME-Version: 1.0
In-Reply-To: <CAL=_i_kKQSHonHni3GMCNs85eUGm=qYaa9GJoJHdAbU8viYFgg@mail.gmail.com>
References: <2e4694f9805ee81ea0b2c79eab06c2d6@mail.gmail.com>
	<CAAyV7nExeZ1xouJAsACm9AvAGuQw0e-0FgVdEOAyzsC5OEn5_Q@mail.gmail.com>
	<54EA5EDA.8010605@gmail.com>
	<CAAyV7nFt3KL_uH4HuA5xQ7HY+3_3=fq=pg0_U1aMrdirETC6LQ@mail.gmail.com>
	<54EA6A99.5010609@gmail.com>
	<CAAyV7nE2Cfr0ohpPnXWnf5agmyGfeirNH-3UGyHEhsDaMvmsoQ@mail.gmail.com>
	<54EA7F15.9030606@gmail.com>
	<54EA891B.6030405@gmail.com>
	<09b9ee836c04b1750614a91bd39a5bed@mail.gmail.com>
	<54EA97A2.4010701@gmail.com>
	<CAL=_i_nn_az7gsu2Y7Qhp29cP1gJ96T_0SmG60rhY12qKvr6qA@mail.gmail.com>
	<661590f4daa710176268b43c1b950583@mail.gmail.com>
	<CAL=_i_kKQSHonHni3GMCNs85eUGm=qYaa9GJoJHdAbU8viYFgg@mail.gmail.com>
Date: Mon, 23 Feb 2015 10:48:46 +0100
Message-ID: <CAB6YZuwfOTyAkHrqndXhRX_35rWbpwS1cFQaUEUZFHPW6T7EBQ@mail.gmail.com>
To: Joe Watkins <pthreads@pthreads.org>
Cc: Zeev Suraski <zeev@zend.com>, PHP internals <internals@lists.php.net>
Content-Type: text/plain; charset=UTF-8
Subject: Re: [PHP-DEV] JIT (was RE: [PHP-DEV] Coercive Scalar Type Hints RFC)
From: pajousek@gmail.com (=?UTF-8?Q?Pavel_Kou=C5=99il?=)

On Mon, Feb 23, 2015 at 10:28 AM, Joe Watkins <pthreads@pthreads.org> wrote:
> Zeev,
>
>>  If you can infer the type with confidence, you can do away with coercion
> code altogether.
>
> Maybe I'm ignorant of something, but isn't the only way you can begin to
> infer the type with real confidence is by having strict typed parameters ?
>
> This sounds like the kind of strict mode we're talking about, where no
> coercion is necessary because inference is so reliable given a good
> starting place (function entry with strictly typed parameters).
>
>>  If you can't, then you're not obligated to generate optimized paths for
> every possible input - you can just defer to the relevant coerce() function.
>
> If the parameters aren't strict but are typed then you need to travel
> coercion code paths somewhere, optimized inline, calling an API function,
> it makes no real difference.
>
> I guess we are hedging our bets that having to travel those paths will suck
> away so much performance, that it will make all of the effort required to
> make any of this a reality seem, somehow ... wasted.
>
>> JIT might end up being about making PHP viable for more CPU-bound use
> cases ...
>
> This is probably quite realistic.
>
> In case anyone is reading and thinks I'm using any of this to justify dual
> mode, I'm not doing that. The original RFC justified it well enough, I just
> happen to disagree with some of the assertions made in this thread and or
> RFC.
>

Hello,

if I understand the issue correctly, not even strongly typed
parameters won't help you infer types of variables with real
confidence?

Imagine this piece of code:
function foo(int $x) { $x = fnThatReturnsRandomScalarType(); return $x; }

Regards
Pavel Kouril