https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96717
--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Jonathan Wakely from comment #1) > Created attachment 49085 [details] > Preprocessed source for a.cc This was prepared on x86_64-pc-linux-gnu. Compile it with -O2 to see the ud2 insn in the .s output.