The result is unpredictable, and I'm puzzled why -- even if Google says that signed integer overflow is "undefined behaviour", but shouldn't result be deterministic, at least?
Not necessarily. I don't know exactly what is happening here, but you might just get some value from a memory address that has not been properly initialized, and could therefore contain anything just being there when you run your program. This may not be very common in Perl, but it does happen in C programs. Just my two cents worth, I don't know enough about PDL to be more helpful.

In reply to Re: [maybe OT] What kind of bug was that? Non-deterministic result with C integer overflow? by Laurent_R
in thread [maybe OT] What kind of bug was that? Non-deterministic result with C integer overflow? by vr

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