Re: Move to Fast ZPP?

Hi Pierre, ----- Original Message ----- From: "Pierre Joye" Sent: Thursday, August 06, 2015

On Aug 6, 2015 1:49 PM, "Matt Wilmas" <php_lists@realplain.com> wrote:

Hi Levi, ----- Original Message ----- From: "Levi Morrison" Sent: Thursday, August 06, 2015

Don't know about Windows now... Visual Studio 2008 and 2012 (not much difference) are NOT optimizing away the code (other times it was GCC

with

issues). :-/ Not sure why. Of course they don't support the necessary compound literals anyway, but I was just testing a manual case... I'll

have

to try and check 2015 version soon.

VS 2015 supports compound literals, I believe.

Yes, VS 2013 added, AFAIK. But I was just talking about optimizing the

code that would use them. A compound literal (void *[]), derived from variadic macro, is needed to transform zend_parse_parameters() into a non-varargs inline function call (since va_arg usage prevents inlining).

The problem in the earlier VS versions, which I simulated manually

without compound literals, is that it doesn't want to optimize away all the inlined stuff, leaving only the result. Definitely can't have something creating several KB of extra instructions! :-)

So unless they improved something in the newest versions, this wouldn't

be able to be used there, unless I can work around it somehow. I don't know if macros, instead of inline functions, inside the main inline function would help or not...

Although, it *would* simplify a couple tiny parts if didn't need to

support MSVC... First, detecting a string *literal* (99% of usage): could just use __builtin_constant_p() instead of a macro trick.

And second, using a variable length array, with size set by, well, a

variable, which I think VS still doesn't support from C99, right? (It's for a "variable" in this case, but always the same, so should optimize like a compile-time size.) If you have a piece of self contained code to test it, we can then add it to the VC test repo to valid what we can support with 7+.

Sure! Simply: size_t num = 4; char foo[num]; I wondered about emulating with _alloca(), but a quick check (in 2008!) shows that it doesn't optimize it out even with a true constant value... - Matt