Re: luajit 2.0 jit bug with and/or expression?

[Mike Pall <mikelu-1204@...>]

Felix Wu wrote:
> The following function ran fine with JIT off (-joff) for both LuaJIT
> 2.0 beta 8 and 9, but got erroneous results with JIT on. Is this a
> known bug?
> 
> (1) with -joff
> 
>     > function fib(n) return (n < 2) and 1 or fib(n-1)+fib(n-2) end
>     > = fib(10)
>     89
>     > =fib(20)
>     10946
> 
> (2) without -joff
> 
>     > function fib(n) return (n < 2) and 1 or fib(n-1)+fib(n-2) end
>     > = fib(10)
>     79
>     > = fib(20)
>     stdin:1: attempt to perform arithmetic on a nil value

Thank you for the bug report and the test case! Fixed in git HEAD.

[That was a wrong data flow optimization hint in the bytecode.
That's why it's of rather basic nature, but only shows up under
very specific circumstances, when the code is JIT-compiled.]

--Mike