[PATCH] D131727: Enable -Wctad-maybe-unsupported in LLVM build

[Mark de Wever via Phabricator via llvm-commits]

Mordante accepted this revision.
Mordante added a comment.
This revision is now accepted and ready to land.

In D131727#3722154 <https://reviews.llvm.org/D131727#3722154>, @dblaikie wrote:

> In D131727#3721466 <https://reviews.llvm.org/D131727#3721466>, @jloser wrote:
>
>> `libc++` doesn't always use the just-built clang. We keep support for the last two versions of clang, so the compiler compatibility checks would be needed, right? Was the flag added in llvm14 or llvm15?
>
> ah, OK. Looks like this is supported back to Clang 9: https://godbolt.org/z/5rzMoKoEv (unknown name on Clang 8, no warning on Clang 9)

Thanks for looking. It would be even safe when it was added in Clang 15, see my review comment.
The libcxx CI failure is not due to this patch, the time-out for the test seems to be too short.

Can you update the commit summary to reflect the current state of the patch?

LGTM from libc++'s point of view, but please wait for other reviewers to look at the LLVM side.



================
Comment at: libcxx/CMakeLists.txt:591
   if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
     target_add_compile_flags_if_supported(${target} PRIVATE
       -Wno-user-defined-literals
----------------
Even if Clang 14 wouldn't support the new flag it would be safe, this CMake macro only adds the flag when it's supported by the compiler.


Repository:
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https://reviews.llvm.org/D131727