https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66714
--- Comment #15 from vries at gcc dot gnu.org --- My guess at this point is that the problem is that in replace_block_vars_by_duplicates, we replace the old decls in the block with new decls, but that the value-exprs that we copy from the old to the new decls still contain the old decls.