[PATCH] D45015: [Preprocessor] Allow libc++ to detect when aligned allocation is unavailable.

[Richard Smith - zygoloid via Phabricator via cfe-commits]

rsmith added a comment.

In https://reviews.llvm.org/D45015#1105372, @vsapsai wrote:

> What when compiler has `__builtin_operator_new`, `__builtin_operator_delete`? If I build libc++ tests with recent Clang which has these builtins and run tests with libc++.dylib from old Darwin, there are no linkage errors. Should we define `__cpp_aligned_allocation` in this case?


I don't see why that should make any difference -- those builtins call the same functions that the new and delete operator call. Perhaps libc++ isn't calling the forms of those builtins that take an alignment argument yet?


Repository:
  rC Clang

https://reviews.llvm.org/D45015