https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68785
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> --- I believe this can happen when native_encode_expr encodes less than the requested number of bytes (thus the program invokes undefined behavior). In this case we read 4 bytes from "" (an empty string). I'm placing some asserts to see what the program does and where.