[PATCH] D53207: Fix bug 26547 - alignof should return ABI alignment, not preferred alignment

[Louis Dionne via Phabricator via cfe-commits]

ldionne added subscribers: dexonsmith, ldionne.
ldionne added a comment.

I'm surprised that nobody discussed the potential for ABI breakage of this change, which changes the result of the `alignof` operator. I'm trying to evaluate what to do in libc++ as a result of this change (now `std::alignment_of` does not match `alignof`) for PR39713 <https://bugs.llvm.org/show_bug.cgi?id=39713>, and I'm wondering whether this issue was considered here. I'm not saying this is a bad change, by the way, I'd simply like to understand what the implications are and find good arguments to convince me to follow the lead in libc++. Pinging @dexonsmith for awareness.


Repository:
  rL LLVM

https://reviews.llvm.org/D53207