[libcxx-commits] [PATCH] D108203: [libc++] Rely solely on using_if_exists for ::aligned_alloc, ::quick_exit and ::timespec_get

[Louis Dionne via Phabricator via libcxx-commits]

ldionne added a comment.

In D108203#2950077 <https://reviews.llvm.org/D108203#2950077>, @dim wrote:

> In D108203#2949462 <https://reviews.llvm.org/D108203#2949462>, @ldionne wrote:
>
>> Expand the change to timespec_get and quick_exit.
>>
>> Note that we'll have to wait for a while before we can submit this change, since we need to drop support
>> for Clang 12 (which doesn't support the attribute).
>
> Hm, that's a pity, I wasn't aware that this attribute was introduced so relatively recently. We have clang (and libc++) 11.0.1 in FreeBSD 12.x, which is going to be supported for a while, still. FreeBSD 13.0 and later have clang/libc++ 12.0.1.

FWIW, I think that's fine. We have a compiler support policy and we should stand by it. We negotiated that policy so it would be reasonable for both users of libc++ and the libc++ project itself, waiting approximately a year before ripping out this workaround is really not a big deal. What's important is that we can do it in a reasonable time frame, and I think that's enough.

For the time being, I'm about to check-in a patch that bypasses this whole logic whenever the compiler supports `using_if_exists`, so from our perspective, this code won't be used anymore anyways.


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https://reviews.llvm.org/D108203