https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103950
--- Comment #1 from Thorsten Otto <ad...@tho-otto.de> --- In gimple_fold_builtin_printf(), a call to printf() with a single-character-string is optimized to putchar(). However that is also done with non-ascii-characters, which in the case of printf("\ff") will call putchar with a value of (-1) == EOF. That happens even if -funsigned-char is used.