[LLVMdev] Visual Studio 2010 build warning & errors

[Michael Spencer]

On Sat, Sep 25, 2010 at 10:53 AM, Ahmed Charles <ahmedcharles at gmail.com> wrote:
> Note: static_cast<bool> doesn't make the warning go away or did you check
> that? I just compiled a small test and it didn't work. The recommended
> solution is:
>
> (expression) != 0
>
> http://msdn.microsoft.com/en-us/library/b6801kcy.aspx
>
> It even says: Casting the expression to type bool will not disable the
> warning, which is by design.

I did not check that, sorry (I've not seen the warning). Thanks for
the proper fix :P.

- Michael Spencer

> On Thu, Sep 23, 2010 at 9:18 AM, Nathan Jeffords <blunted2night at gmail.com>
> wrote:
>>
>>
>> On Thu, Sep 23, 2010 at 4:04 AM, Michael Spencer <bigcheesegs at gmail.com>
>> wrote:
>>>
>>> On Thu, Sep 23, 2010 at 2:40 AM, Nathan Jeffords
>>> <blunted2night at gmail.com> wrote:
>>> > here are a couple of patches to address some warnings
>>> > in Microsoft compilers, and a build error in vs2010 in particular
>>> > vs2010-errors.patch:
>>> > In SelectionDAGISel,  std::pairs or pointers are being constructed
>>> > using a 0
>>> > as an initializer causes an error inside the std::pair constructor. I
>>> > think
>>> > changes to language in support of the nullptr keyword caused this
>>> > break.
>>>
>>> Yep, people keep doing this. I've been behind on the trunk for a bit,
>>> but I was surprised to see this come up again. This is the correct
>>> fix, but please make sure you stick within 80 cols.
>>>
>>> > vs2010-warnings.patch:
>>> > This patch fixes a couple of annoying warnings that show up all over
>>> > the
>>> > place because they are in headers. At least for Microsoft compilers,
>>> > conversion of a int to bool requires the compiler to convert non-zero
>>> > to one
>>> > and so the compiler warns of the performance issue. My fix is to
>>> > explicitly
>>> > perform the conversion so the compiler knows I'm aware and doesn't warn
>>> > me.
>>> > I don't know the behavior of other compilers in this respect, so I
>>> > don't
>>> > know if it should be committed. The other solution would be to change
>>> > the
>>> > return type of the accessors function to return ints, though this could
>>> > move
>>> > the warning elsewhere.
>>> > -Nathan
>>>
>>> This fix looks like a case of 3am programming. I think using
>>> static_cast<bool> is clearer.
>>>
>>> - Michael Spencer
>>
>> here are updated versions
>> - Nathan
>>
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>
>
>
> --
> Ahmed Charles
> http://www.ahmedcharles.com
>