r261297 - Implement the likely resolution of core issue 253.

[Ismail Donmez via cfe-commits]

Hi,

On Fri, Feb 19, 2016 at 3:52 AM, Nico Weber via cfe-commits
<cfe-commits at lists.llvm.org> wrote:
> Author: nico
> Date: Thu Feb 18 19:52:46 2016
> New Revision: 261297
>
> URL: http://llvm.org/viewvc/llvm-project?rev=261297&view=rev
> Log:
> Implement the likely resolution of core issue 253.
>
> C++11 requires const objects to have a user-provided constructor, even for
> classes without any fields. DR 253 relaxes this to say "If the implicit default
> constructor initializes all subobjects, no initializer should be required."
>
> clang is currently the only compiler that implements this C++11 rule, and e.g.
> libstdc++ relies on something like DR 253 to compile in newer versions.  This
> change  makes it possible to build code that says `const vector<int> v;' again
> when using libstdc++5.2 and _GLIBCXX_DEBUG
> (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60284).
>
> Fixes PR23381.

Since nearly all Linux distros now ship gcc5, it would be nice to have
this fix in 3.8 release.

Thanks,
ismail