[Bug tree-optimization/78312] [7 Regression] wrong code probably due to VRP of multiplication

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78312

--- Comment #2 from Zdenek Sojka <zsojka at seznam dot cz> ---
(In reply to Richard Biener from comment #1)
> Hmm.
> 
> So [0, 1] * ~[1, 65534] gets
> 
> MEET ([0, 1] * [0, 0] == [0, 0],
>       [0, 1] * [65535, 65535] == ~[1, 65534]) == ~[1, 65534]
> 
> that looks ok to me.
> 
> And then ~[1, 65534] * ~[1, 65534] is [0, 1], also ok.
> 

Thanks, I didn't realize that ((65535 * 65535) & 0xffff) == 1.