Not sure if there is a problem here. But I don't have time to look further, and probably better to get somebody to double check.

In

, it seems to default to use "This diagnostic flag exists for GCC compatibility, and has no effect in Clang." in some situations. I don't fully understand the details, but I have observed a few warnings with this message in the documentation that I don't think gcc ever had.

So sure, -Wabi may be there for gcc compatibility. It was there even in the clang 4.0.0 documentation.

But then you get things as -Wexport-unnamed. Which,

• I can't find in any version of the gcc documentation.
• Was documented as a normal, valid, warning in the clang 16.0.0 documentation.

-Wexport-unnamed was removed in e5c7904, which just says "This patch removes these diagnostics". It doesn't say anything about being kept as a flag for GCC compatibility.

Is it possible some warnings have not been properly removed, and ended up marked as "for GCC compatibility" incorrectly?
If so, I can list the following suspects (there may be more, specially if removed recently):

• https://clang.llvm.org/docs/DiagnosticsReference.html#wauto-import was https://releases.llvm.org/14.0.0/tools/clang/docs/DiagnosticsReference.html#wauto-import
• http://clang.llvm.org/docs/DiagnosticsReference.html#wexport-unnamed was https://releases.llvm.org/16.0.0/tools/clang/docs/DiagnosticsReference.html#wexport-unnamed
• https://clang.llvm.org/docs/DiagnosticsReference.html#wgnu-empty-initializer was https://releases.llvm.org/16.0.0/tools/clang/docs/DiagnosticsReference.html#wgnu-empty-initializer
• https://clang.llvm.org/docs/DiagnosticsReference.html#wignored-pragma-optimize was https://releases.llvm.org/14.0.0/tools/clang/docs/DiagnosticsReference.html#wignored-pragma-optimize
• https://clang.llvm.org/docs/DiagnosticsReference.html#wreturn-std-move was https://releases.llvm.org/12.0.0/tools/clang/docs/DiagnosticsReference.html#wreturn-std-move
• https://clang.llvm.org/docs/DiagnosticsReference.html#wgnu-binary-literal was https://releases.llvm.org/18.1.0/tools/clang/docs/DiagnosticsReference.html#wgnu-binary-literal
• https://clang.llvm.org/docs/DiagnosticsReference.html#wgnu-offsetof-extensions was https://releases.llvm.org/18.1.0/tools/clang/docs/DiagnosticsReference.html#wgnu-offsetof-extensions