[LLVMdev] Visual Studio 2010 build warning & errors

[Ahmed Charles]

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.

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
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