[Piglit] [PATCH 2/3] Use alloca instead of variable length arrays

[Matt Turner]

On Fri, Dec 12, 2014 at 2:13 PM, Jan Vesely <jan.vesely at rutgers.edu> wrote:
> On Fri, 2014-12-12 at 13:37 -0800, Matt Turner wrote:
>> On Fri, Dec 12, 2014 at 1:23 PM, Jan Vesely <jan.vesely at rutgers.edu> wrote:
>> > On Fri, 2014-12-12 at 12:58 -0800, Matt Turner wrote:
>> >> I'm curious what the motivation for removing variably-sized arrays is,
>> >> but if I accept that that's a good thing to do then the first patch
>> >> makes sense, but I don't understand this one.
>> >>
>> >> How is a variably-size array different from using alloca()?
>> >
>> > variable size arrays are a c99 feature not supported by msvc (that's why
>> > there is a warning). I don't know which parts actually do need to build
>> > using msvc, but it seemed like a good idea to reduce warning output (and
>> > improve consistency with code that needs to build using msvc).
>> >
>> > In the first patch I used alloca+free, because it looked nicer than
>> > doing size arithmetic. The other cases allocate byte arrays, and the
>> > only difference is that alloca (_alloca) is supported by msvc.
>>
>> Okay, then this patch doesn't do anything useful, since these tests
>> shouldn't be built with MSVC. dma_bufs are a Linux thing.
>
> yes, I understand that, the point was not to build them using msvc.
>
> the patch usefulness is in enabling switch Wvla to error instead of
> warning. other than that, it just reduces warning output.

Ah, I see. Okay.

For my own curiosity, does this actually change the compiled code?