[Bug tree-optimization/118657] Missed optimization (unreachable branch could be pruned after taking into account the possible values of a constexpr lookup table)

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118657

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andi Kleen from comment #3)
> I don't think you need range analysis for this, just the constexpr array
> lookup needs to supply a constant.

In the simplified testcase, saying all values of the array is the same and zero
is OK for that but as mentioned below the referenced simplified testcase was
simplified too much. Having a full range of the values inside the array would
improve other code besides bounds checking too.