https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91310
--- Comment #6 from Thomas Koenig <tkoenig at gcc dot gnu.org> --- Comment on attachment 46648 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=46648 test case 1 Oops, correction. If len is small enough, the test case can be valid (well, it could be if str was ever assigned). Digging further...