https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111436
--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> --- Please re-read the notice that was shown before you created this bug: "Before reporting a bug, please read the bug writing guidelines, please look at the list of most frequently reported bugs, and please search for the bug." "Before reporting that GCC compiles your code incorrectly, compile it with gcc -Wall -Wextra and see whether this shows anything wrong with your code. Similarly, if compiling with -fno-strict-aliasing -fwrapv makes a difference, your code probably is not correct." Your code produces the expected results with -fno-strict-aliasing and as it says, that means your code is probably not correct. In this case, it's definitely not correct. The reason std::bit_cast doesn't allow more general types is because C++ doesn't support doing it. You can't just reinterpret_cast and expect it to work.
