[llvm-dev] Non-void function does not return value

[Sean Silva via llvm-dev]

I think this is the intended use of enable_if, no?

http://en.cppreference.com/w/cpp/types/enable_if
"This metafunction is a convenient way to leverage SFINAE to conditionally
remove functions from overload resolution based on type traits and to
provide separate function overloads and specializations for different type
traits"

-- Sean Silva

On Tue, May 10, 2016 at 11:07 PM, Luo, Xionghu via llvm-dev <
llvm-dev at lists.llvm.org> wrote:

> Hi Chandler,
>
> I scanned the LLVM source code, and found some potential code issues, take
> the piece of code in file ‘./include/llvm/Support/Allocator.h’ for example:
>
>
>
>
>
> 80
>
>   /// \brief Deallocate space for a sequence of objects without
> constructing them.
>
> 81
>
>   *template* <*typename* T>
>
> 82
>
>   *typename* std::enable_if<
>
> 83
>
>       !std::is_same<*typename* std::remove_cv<T>::type, *void*>::value,
> *void*>::type
>
> 84
>
> [image:
> https://otckw.jf.intel.com:8080/review/review/images/folding/collapse_top.png]
>
>   Deallocate(T *Ptr, size_t Num = 1) {
>
> 85
>
>     Deallocate(*static_cast*<*const* *void* *>(Ptr), Num * *sizeof*(T));
>
> 86
>
> [image:
> https://otckw.jf.intel.com:8080/review/review/images/folding/collapse_bottom.png]
>
>   }
>
>
>
>
>
> If the typename T is void, the std::is_same will be FALSE, which means the
> std::enable_if::type is UNDEFIED.
>
> So do you think it need a fix?
>
> Thanks.
>
>
>
>
>
> Luo Xionghu
>
> Best Regards
>
>
>
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>
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