die immediately but give some kind of intelligable error about too large a string repetition. This is because ~ in perl5 always gives an unsigned number, so ~@; is not -1 but 2**32-1 or 2**64-1. If that's wrong, my second guess is crashing without any message with a fatal signal, like SIGABRT or SIGSEGV.

died with the error message "Out of memory!". Note how unusual this error is: it doesn't have the file, line, and other usual info appended, and it has an excalmation mark.