https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113904
--- Comment #4 from sandra at gcc dot gnu.org --- Dynamic selectors are completely broken on mainline, since the patches that at least partially implements this feature for metadirectives has not been approved or committed yet. I'm also very much aware that there is not even a proposed patch to make this work for "declare variant" yet, although the metadirectives work provides the underlying primitives that ought to be adaptable for "declare variant" as well. I suggest not messing around with incremental fixes meanwhile that would step on the already-posted patches which cannot be considered until GCC 14 has branched. https://gcc.gnu.org/pipermail/gcc-patches/2024-January/642005.html