[llvm] r280750 - Avoid using alignas and constexpr.

[Rafael Espíndola via llvm-commits]

On 20 October 2016 at 17:18, Reid Kleckner <rnk at google.com> wrote:
> On Wed, Oct 19, 2016 at 12:02 AM, Justin Bogner <mail at justinbogner.com>
> wrote:
>>
>> Rafael Espindola via llvm-commits <llvm-commits at lists.llvm.org> writes:
>> > Author: rafael
>> > Date: Tue Sep  6 15:36:24 2016
>> > New Revision: 280750
>> >
>> > URL: http://llvm.org/viewvc/llvm-project?rev=280750&view=rev
>> > Log:
>> > Avoid using alignas and constexpr.
>> >
>> > This requires removing the custom allocator, since Demangle cannot
>> > depend on Support and so cannot use Compiler.h.
>>
>> Can we use alignas and constexpr now that we're dropping MSVC 2013, or
>> did these also cause problems on other compilers? If 2013 was the
>> bottleneck, should we add back the custom allocator here?
>
>
> Go for it, I tried out the basic constructs with MSVC 2015 and it all works.
> The only question is, do you think the custom arena allocator is worth it?
> For a demangler, it might be.

We can add back any uses of alignas and constexpr, but my
understanding is that we have to at least have the option of using
malloc given how the desire to use this code as the implementation of
abi::__cxa_demangle.

Cheers,
Rafael