[Bug tree-optimization/55157] Missed VRP with != 0 and multiply

[aldyh at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55157

--- Comment #5 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
(In reply to Aldy Hernandez from comment #4)

> +  // Reflect the mask as a simple range.  For example, a mask of
> +  // 0xff00 could be represented as [0,0][0x100, 0xffff].
> +  if (TYPE_UNSIGNED (type ()) && prec > 1)

Bonus points for making it work with signed.  I'm not smart enough to do that
:).