https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78695
--- Comment #4 from Bill Schmidt <wschmidt at gcc dot gnu.org> ---
The offending line appears to be
rtx_insn *and_insn = DF_REF_INSN (base_def_link->ref);
which would seem to indicate an inconsistency in the dataflow information at
this point. It would be good to be able to reproduce this...
