[llvm-dev] Using C++14 code in LLVM

[Joerg Sonnenberger via llvm-dev]

On Mon, Oct 03, 2016 at 10:38:32AM -0700, Justin Bogner via llvm-dev wrote:
> Zachary Turner via llvm-dev <llvm-dev at lists.llvm.org> writes:
> > A thread was started over the summer to discuss the timeline for bumping
> > LLVM up to Visual Studio 2015 to enable the use of various new language
> > features.  Currently the ETA for this is sometime in mid-October, so within
> > 2-3 weeks.
> >
> > With this happening imminently, I thought it would be worth tossing this
> > out there and seeing what people think.
> >
> > With VS on 2015, the major lagging compiler is going to be GCC.  Our
> > minimum GCC requirement is 4.7, which is quite old (almost 4 years for
> > anyone keeping count).  What are the challenges with pushing this forward?
> >
> > With VS2015, the biggest remaining missing C++14 features are variable
> > templates, sized allocation, and extended constexpr.  But it gains generic
> > lambdas, init-captures, decltype(auto) return, and auto return without
> > requiring the trailing -> decltype syntax.
> 
> I'm not convinced that the cost is worth the gain for these features.

That is my concern as well. It seems quite a bit like "Oh new, shinny,
want!" Keep in mind that LLVM is now integral part of the Mesa
toolchain. The requirements here do not only affect developers, but
there are a lot of users impacted directly by the choices made.

Joerg